Download PDF: Service Manual for Yale A803 (MPC LC_SC) Forklift

Sheet 1: Operating Instructions

OPERATING INSTRUCTIONS OPERATING INSTRUCTIONS-GENERAL Before attempting to operate this truck, carefully read and understand these operating procedures.

Make sure the truck is in proper operating condition. Visually inspect the entire truck for any damage that may have occurred during shipment.

NOTE: Throughout this manual the terms right, left, front and rear relate to the viewpoint of an operator walking with or riding on the truck with the forks trailing.

Familiarize yourself with the information contained on the nameplate which is located on the drive unit top plate. Information on this nameplate is as follows: Serial Number This is an identification number assigned to this particular truck and should be used when ordering service parts or when requesting any information from your Yale industrial truck dealer. The serial number is a six digit number preceded by a letter and is stamped on the truck frame and on the nameplate.

Model Code The model number and the serial number should be used when requesting information. An explanation of the model code is located on Page B of this manual.

Truck Weight This is the approximate weight of the truck without a load on the forks. This weight plus the weight of the load to be moved must be considered when operating on elevated floors, elevators, etc.

Capacity Rating This rating shows the maximum load capacity of this truck. Personal injury and damage to the truck can occur if the capacity is exceeded.

This truck meets all applicable mandatory requirements of ANSI B56.1-Safety Standard for Powered Industrial Trucks at the time of manufacture. In addition, these trucks are classified by Underwriters' Laboratories, Inc. and/or approved by Factory Mutual Engineering Corporation for the type designation shown on the nameplate. Consult UL Index of Classified Products and FM Approval Guide.

No additions, omissions or modifications should be made that will affect compliance to the previously stated requirements or in any way minimize the effectiveness of the safety devices.

Safety and informational labels are located in conspicuous locations on this truck and should be strictly followed. Check the nameplate of each truck before operation. These safety and informational labels must be replaced immediately if missing or defaced. Labels will vary with type of truck and equipment installed. Refer to the Parts Manual for part number and location for all labels.

Sheet 1: Operating Instructions

Figure 1-1 - Serial Number, Nameplate, and Warning Label Locations (MAW, MLA and MPE) 1.

2.

3.

4.

LABEL, DIRECTION ARROW LABEL, OPERATOR WARNING SERIAL NUMBER, FRAME SERIAL NUMBER, NAMEPLATE

Figure 1-2 - Serial Number, Nameplate, and Warning Label Locations-MPC 1.

2.

3.

4.

LABEL, DIRECTION ARROW LABEL, OPERATOR WARNING SERIAL NUMBER, FRAME SERIAL NUMBER, NAMEPLATE

Sheet 1: Operating Instructions

Figure 1-3 - Serial Number, Nameplate, and Warning Label Locations-MTR 1.

2.

3.

4.

LABEL, DIRECTION ARROW LABEL, OPERATOR WARNING SERIAL NUMBER, FRAME SERIAL NUMBER, NAMEPLATE

Figure 1-4 - Safety and Informational Labels 1.

2.

LABEL-DIRECTIONAL ARROW PLATE-BATTERY SIZE

Sheet 1: Operating Instructions 3.

4.

5.

6.

7.

PLATE-U.L. APPROVAL LABEL-PARKING BRAKE LABEL-COAST CONTROL LABEL-FAST SPEED LABEL-NO RIDERS

OPERATOR PRE-CHECKS AND INSPECTION Before each shift, every 8 hours, it is the operator's responsibility to carry out the following checks and inspections before beginning truck operation. Do not operate truck if it is in need of repair, if it is in an unsafe condition, or might contribute to an unsafe condition. Remove the key and report the condition to the proper authority. If the truck becomes unsafe in any way while you are operating it, STOP operating the truck and report the matter immediately to the proper authority.

Basic maintenance information and the Recommended Schedule of Maintenance are in the Operational Maintenance Manual, Part Number 5192938-04, located in the document holder on the compartment cover. Also refer to Section 2 of this manual.

1.

Make sure all capacity, safety and informational plates or labels are attached. This truck is not considered safe to use without a legible, properly filled out nameplate. Contact Yale Materials Handling Corporation or your local dealer for Yale Industrial Trucks if the nameplate is not present and legible. See the Operating Manual for label and plate locations.

2.

Inspect truck for any damage that might have occurred during the previous shift.

3.

Inspect truck before and after operating, for any signs of external leaking of the battery, hydraulic system, etc.

4.

Check hydraulic hoses for leaking, chafing, cuts or reinforcement showing through the outside of the hose.

5.

Operate brakes, all hydraulic controls, reversing switch, direction and speed control and steering. Make sure they operate freely and return to their proper positions (if equipped).

6.

Inspect condition of wheels and tires.

7.

Inspect forks for any damage (if equipped).

8.

Test horn and any other accessories. Make sure they are properly mounted and in good working order.

9.

Operate truck and make sure all gauges and meters are functioning properly.

10. Make sure any unusual noises are investigated immediately.

OPERATING PROCEDURE-GENERAL Practice with an empty truck until you (the operator) have achieved satisfactory smoothness in all operations, traveling, lifting, etc.

• •

Never ride a truck that is designed for walk operation.

Watch clearances, especially around forks. Watch tail swing. The driver must be aware that the forks can sometimes extend beyond the load. This may cause the operator to hit an object or lift another load.

•

Do not permit passengers to ride on the truck.

•

Look in the direction of travel and keep a clear view of the path of travel.

• • •

If visibility is impaired by the load, operate truck with the forks trailing and face in the direction of travel or use extreme caution.

The high speed control should only be used when riding on the truck.

Stop, start, travel, steer and brake smoothly. Slow down for turns and on uneven or slippery surfaces that could cause truck to overturn or slide.

Sheet 1: Operating Instructions

• •

Before entering trucks or trailers, be certain the brakes on the truck or trailer are applied and wheel chock(s) are in place. If trailers are not coupled to a tractor, supports may be needed to prevent upending or corner dipping. Check the flooring of trucks, trailers and railroad cars for breaks and weakness before driving onto them.

Before driving over a dockboard or bridge plate, be certain that it is properly secured. Drive carefully and slowly across the dockboard or bridge plate and never exceed its rated capacity.

•

Maintain a safe distance from the edge of ramps or platforms. Do not use this truck for opening or closing freight doors.

•

Do not run over objects on the roadway surface as truck stability and steering could be adversely affected.

•

Do not push extra loads with the truck.

• •

When approaching cross-aisles, slow down, sound horn and keep to the right side of aisle. Operate truck under all conditions at a speed that will permit it to be brought to a stop in a safe manner.

On inclines, travel with the load or forks downhill. If the operator should lose footing or control of the lift truck, the operator will not be in the path of travel. Do not turn on an incline. For stability reasons, a lift truck must not be driven across an incline. Motorized Hand lift trucks are not intended for operation on grades greater than 10% (a grade that changes 1 foot in elevation for every 10 feet of horizontal travel).

•

Operate truck on all grades with the forks downhill.

•

Yield the right of way to pedestrians.

•

Observe all traffic regulations, including authorized plant speed limits. Under normal traffic conditions, keep to the right.

Maintain a safe distance from the truck ahead (approximately three truck lengths), and keep the truck under control at all times.

•

Report all accidents involving personnel, building structures and equipment to the proper authority.

•

Avoid any abrupt moves. Be a professional. "HANDLE WITH CARE."

•

Do not remove load backrest extension, if so equipped, unless specifically authorized.

•

Make sure that fork length is at least 2/3 of load length.

•

Carry the load flush against the battery or load backrest.

•

Allow no one under or near load or lifting mechanism.

•

Watch that your load does not exceed the capacity rating of the truck. The truck capacity is posted on the nameplate which is attached to the truck at the factory.

•

Do not handle unstable or loosely stacked loads.

•

Center the forks under the skid or bin to be handled.

•

Do not start or operate this truck or any of its functions or attachments if you are not in the designated operator's position.

•

Never allow anyone to ride on your truck and never allow anyone other than a qualified professional to operate your truck.

SHUT DOWN PROCEDURE

Sheet 1: Operating Instructions When leaving truck unattended, fully lower forks, shut off power, set brake, set coast control to off (when equipped), neutralize controls and remove key. If you park the truck on an incline, chock the wheels.

SAFETY AND OPERATIONAL CHECK LIST A "Daily Check List" similar to the one shown on the next page should be used every day before operating the truck. The check lists are available in tablet form with 50 sheets per tablet and can be obtained from your local Yale industrial truck dealer for a nominal fee.

Both this manual and the Operating Manual contain the Recommended Schedules of Maintenance which should be used as a guide along with the Lubrication Instructions.

A professional operator should also be familiar with the information contained in the American National Safety Standard for Powered Trucks-ANSI B56.1.

NOTE: This Daily Check List is available for the Operator. Some items on this list may not be applicable to your truck.

This convenient check list is in tablet form and can be ordered through your Yale Industrial Truck Dealer. Form Number 944-6418-A.

Sheet 1: Operating Instructions

Sheet 1: Operating Instructions

Figure 1-5 - Motorized Hand Trucks and Tractor

OPERATING CONTROLS-CONTROL HANDLE The controls and configuration of the handle will vary by model. The control handle has the following functions. Direction and speed of travel are controlled by a butterfly switch on the MPW models and by the handle grips on all other models. Buttons control lift, lower and horn. A reversing button is on the end of the control handle on the MPW, MLW and MPE models. The brakes are applied by fully raising or fully lowering the control handle on the MPW, MLW and MPE models. The brakes are applied by hand pressure on MPC and MTR units.

Sheet 1: Operating Instructions The MPC and MTR units also have a parking brake which is mounted at the base of the control handle. These units also have a three position tilt control to adjust the height of the control handle to the operator's preference.

The MLW platform truck is available with a 6 inch or 9 inch high platform and a variety of lengths to accommodate a wide range of bins and skids.

The callouts listed in Figure 1-6 through Figure 1-8 are described in the following paragraphs.

Figure 1-6 - Control Handle-MPW

Figure 1-7 - Control Handle-MPE

Figure 1-8 - Control Handle-MPC and MTR Reversing Button.

1.

The reversing button is designed to help protect the operator from being pinned between the control handle and another

Sheet 1: Operating Instructions object. If the button contacts the operator and is pushed, when the control handle is in the operating position, the truck will move away from the operator as long as the button is pressed. Once the button is released, the truck cannot be driven toward the operator until the switch is "reset", by moving the control handle to a "brake on" position. There is no reversing button on the MPC or MTR models.

WARNING: The reversing button will cause rapid acceleration of the truck away from the operator.

Horn Button.

2.

Press the horn button to operate the horn when the key switch is on. Alert pedestrians or other operators of your presence. Use Wisely!

Direction and Speed Control 3.

The butterfly switch on the MPW models or the handle grips on all other models control the direction and speed of the truck. Lower the control handle to the "brake off" position. Press the butterfly switch or turn the handle grips in the desired direction of travel. The degree of movement or rotation will determine the speed at which you travel.

The operator can change the direction of travel while the lift truck is moving, by moving the direction control in the opposite direction. The lift truck will come to a stop and then accelerate in the opposite direction. This action is called "PLUGGING".

Lift Button 4.

Press the button to raise the forks.

Lower Button 5.

Press the button to lower the forks.

Brakes 6.

Used on MPC and MTR models only. Apply brakes by hand pressure on the brake levers located on either side of the control handle.

Sheet 1: Operating Instructions

Figure 1-9 - Hand Brake Levers-MPC and MTR

BRAKING Several methods of stopping are available. One method of stopping and direction changing is plugging. Plugging means reversing the direction control while traveling, causing the unit to slow to a stop. Return the control to the OFF position to remain stopped. If the control is not returned to OFF, the lift truck will accelerate in the opposite direction.

If the battery is low or if power to the motor has been interrupted plugging will not be effective.

On the MPW, MLW and MPE trucks a second method of stopping is by fully raising or lowering the control handle. This will operate the mechanical brake. The brake drum is mounted on the bevel gear shaft of the drive unit. Applying the brake shuts off the drive motor.

Figure 1-10 - Braking Application-MPW, MPE and MLW A third method of stopping the lift truck is to use normal friction (coast) by moving the speed control to OFF. The brakes on the MPC and MTR are mounted on the control handle and are applied by pressure to the hand brake levers. The brakes can be operated with either hand. See Figure 1-9.

PARKING BRAKE A parking brake is mounted at the base of the control handle column on the MPC and MTR units.

Sheet 1: Operating Instructions

Figure 1-11 - Parking Brake-MPC and MTR The parking brake is not automatically applied. Set the parking brake whenever you leave the truck. Lift up on parking brake knob to engage the parking brake. The parking brake when properly adjusted, will hold the truck on a 10% grade. See the Maintenance Manual for adjusting procedures.

STEERING On the MPW, MLW and MPE models, turn the lift truck to the right or left by moving the control handle in the desired direction of travel.

Make sure there is adequate turning clearance. When traveling in reverse (forks first) the lift truck will move to the side when turning. This movement is called "tailswing". The operator must be aware of tailswing and always check to make sure the tail swing area is clear before turning.

Figure 1-1 - Steering Directions-MPW, MLW and MPE To steer the MPC units move the control handle away from the intended direction of travel.

Sheet 1: Operating Instructions

Figure 1-2 - Steering Directions-MPC To steer the MTR unit move the control handle away from the intended direction of travel.

Figure 1-3 - Steering Directions-MTR

BATTERY CONNECTOR The battery connector is located on top of the truck. One half of the connector is attached to the battery cables. The other half of the connector is attached to the truck's electrical system. Be sure both halves of the connector are pushed completely together for proper contact. This is important, as loose connectors will produce heat and burn the contacts. To disconnect, pull up on the connector.

CAUTION: Do not disconnect the connector by pulling on the cable.

Sheet 1: Operating Instructions

Figure 1-4 - Battery Connector

BATTERY INDICATOR AND HOURMETER (OPTIONAL) A combination battery indicator/hourmeter or separate battery indicators and hourmeters are available for this truck as optional equipment.

Figure 1-5 - Battery Indicator/Hourmeter The battery indicator features a 10 LED (Light Emitting Diode) display of state-of-charge. As the battery's state-of-charge decreases, successive LED's light up. Only the LED indicating the state-of-charge is illuminated. At 70% of discharge an LED will flash, indicating "energy reserve". At 80% of discharge both bottom LED's will alternately flash, indicating "empty". The battery should now be recharged.

The hourmeter continually displays total operation hours. The primary function of the hourmeter is to determine maintenance intervals as outlined in the Recommended Schedules of Maintenance located in the Operational Maintenance Manual.

HANDRAIL CONTROL-MPE The handrail controls are available for the operator when riding on the platform. The controls are similar to those on the control handle, lift lower and horn. The handrail control has one additional button, the fast speed button.

Sheet 1: Operating Instructions

Figure 1-6 - Handrail Controls-MPE Fast Speed Button -This button only needs to be pushed once and it locks into a higher speed range. To discontinue use of the Fast Speed Button, return the direction/speed control to neutral. Use this control only when the operator is riding on the truck.

FAST SPEED CONTROL-MPC AND MTR High speed is controlled by a foot switch for long distance travel. The switch is on the floor of the rider compartment. The truck will operate in the higher speed range as long as the operator's foot is on the switch.

Figure 1-7 - Fast Speed Control-MPC and MTR

PICK ASSIST - MPE (OPTIONAL) The pick assist option is designed to be used with the coast control option. The operator must walk alongside and stay clear of the truck. With coast control set to the "coast" position, depress the inside handle grip and press the button with thumb to travel in the forward direction (forks trailing). Release the button and the truck will coast to a stop. Be sure the path of travel is clear before operation.

Sheet 1: Operating Instructions

Figure 1-8 - Pick Assist-MPE

COAST CONTROL-MPE (OPTIONAL)

WARNING: When coast control is set the brake is not automatically applied when control handle is released.

A coast control feature is available for the MPE truck as optional equipment. To coast, set the coast control selector to the COAST position When set, the coast control holds the steer handle in the BRAKE OFF position. When the control handle is released the brake is not automatically applied and the truck will coast. To apply the brake, when using the coast control, push the handle to the vertical position and hold. To discontinue use of the coast control, set the coast selector to the BRAKE position. The control handle will return to the brake on position when released for parking or automatic braking. The coast control should only be used when the operator is using the truck as a walkie model.

Figure 1-9 - Coast Control-MPE

TILT CONTROL The control handle column is equipped with a three position tilt control. To adjust the tilt angle, loosen both knobs and move the control handle to the desired position. After the desired position has been selected tighten both knobs before operating truck.

Sheet 1: Operating Instructions

Figure 1-10 - Tilt Control-MPC and MTR

DESIGNATED OPERATOR POSITION The proper operator position for Walkie motorized hand trucks is shown in Figure 1-11 through Figure 1-15.

Travel with forks trailing when possible. Steering the truck is easier with the forks trailing. Walk ahead of the truck and to one side. Lead the truck with either side of the control handle. Operate the speed/direction control with one hand. Always look in the direction of travel.

Figure 1-11 - Forks Trailing Position Operate forks first when entering a confined area or elevator. Operate with the forks downhill when traveling on an incline.

Keep both hands on the control handle and within the handle guards. Always look in the direction of travel.

Figure 1-12 - Forks First Position When traveling facing the forks on the MPW and MPE units; place both hands on the steering handle. When traveling with the forks to the rear of the operator, use one hand and walk to one side of the truck. Should the truck fail to stop for any reason, you (the operator) will not be in the path of the truck.

Sheet 1: Operating Instructions Keep your arm straight. If the truck moves away from you, your stiff arm will force the handle down into a braking position. If the truck moves toward you, a stiff arm forces the handle up into the braking position.

Figure 1-13 - Rider Position-MPE On the MPE models, the operator should stand to one side of the steering handle, place one hand on the steering handle and one hand on the handrail. The handrail control for high speed should only be used when traveling from the riding position. The operator should always face in the direction of travel.

When traveling on the MPC and MTR units the operator should stand in the operator's compartment and face in the direction of travel.

Figure 1-14 - Rider Position-MPC Operate forks first when entering a confined area or elevator. Operate with the forks downhill when traveling on an incline.

Keep both hands on the control handle and within the handle guards. Always look in the direction of travel.

Sheet 1: Operating Instructions

Figure 1-15 - Rider Position-MTR

OPERATING PROCEDURES 1.

Apply power to the truck by connecting both halves of the battery connector. Turn the key switch to the ON position.

2.

On the MPW, MLW and MPE trucks move the control handle downward away from the upright position. This will energize the electrical system and release the brakes. The brakes are automatically applied when the steering handle is in the extreme upper or lower position.

Release the parking brake on the MPC and MTR trucks.

3.

Depress the butterfly switch or turn the handle grip in the desired direction of travel and rotate until the desired speed is reached. The operator can change the direction of travel while the lift truck is moving, by moving the direction control in the opposite direction. The lift truck will come to a stop and then accelerate in the opposite direction. This action is called "PLUGGING".

4.

The speed/direction control and the brakes can be operated with either hand on the MPC and MTR models. Travel with forks or coupler trailing whenever possible. Steering the lift truck is easier with the forks or coupler trailing.

5.

When the coast control on the MPE truck set to the coast position, the steer handle in the BRAKE OFF position. When the control handle is released the brake is not automatically applied and the truck will coast. To apply the brake, when using the coast control, push the handle to the vertical position and hold. To discontinue use of the coast control, set the coast selector to the BRAKE position. The control handle will return to the brake on position when released for parking or automatic braking.

WARNING: Always come to a complete stop before leaving the truck. Set the parking brake.

SAFE MAINTENANCE PROCEDURES Your Yale Industrial Truck, as manufactured, meets all the applicable mandatory requirements of ANSI B56.1-Safety Standard for Powered Industrial Trucks. In addition, all standard trucks conform to the Underwriters' Laboratories requirements for the Type Designation shown on the nameplate. The truck is also equipped with certain safety devices as standard equipment. For example, all high lift trucks are equipped with a load backrest extension and high lift rider trucks with an operator's overhead guard. When remote elevating control is specified, an operator's work platform is supplied.

No additions, omissions or modifications should be made that will affect compliance to the above requirements or in any way minimize the effectiveness of the safety devices.

The following instructions have been prepared for your safety and the safety of your fellow workers during maintenance operations and should be strictly followed. Carefully read and understand the maintenance procedures before attempting to repair the truck. When in doubt of any maintenance procedure, contact your local Yale industrial truck dealer.

Sheet 1: Operating Instructions 1.

Powered industrial trucks may become hazardous if maintenance is neglected. Therefore, adequate maintenance facilities, personnel and procedures should be provided.

2.

The Recommended Schedules of Maintenance should be used as a guide for inspection of the truck.

3.

Only qualified and authorized personnel should be permitted to maintain, repair, adjust and inspect the truck.

4.

The work area should be properly ventilated. Keep shop clean and floor dry.

5.

Avoid fire hazards and have fire protection equipment present. Do not use an open flame to check level of electrolyte.

Do not use open pans of fuel or flammable cleaning fluids for cleaning parts.

6.

Raise the lift truck only if it is on a solid level floor. Use solid one piece blocks or other positive truck positioning devices to support the truck. Chock the wheels to prevent movement of the truck.

7.

Disconnect the battery. Attach a DO NOT OPERATE tag to the control handle.

8.

Before removing any component from the truck, make sure that the lifting mechanism (hoist) and slings are of the proper capacity and in good condition.

9.

When working on the hydraulic system, be sure the power is turned off and the hydraulic pressure is relieved in hoses and tubes.

10. Brakes, steering mechanisms, control mechanisms, warning devices, guards and safety devices should be inspected regularly and maintained in a safe operating condition.

11. All parts of lifting mechanisms should be carefully and regularly inspected and maintained in a safe operating condition.

12. All hydraulic systems should be regularly inspected and maintained in conformance with the maintenance schedules. Lift cylinders, valves and other similar parts should be checked to assure that "drift" has not developed to the extent that it would create a hazard.

13. Special trucks or devices designed and approved for hazardous area operation should receive special attention to ensure that maintenance preserves the original, approved safe operating features.

14. Modifications and additions which affect capacity and safe truck operation should not be performed by the customer or user without the manufacturers prior written approval. Capacity, operation and maintenance instruction plates, tags or labels should be changed accordingly.

15. Capacity, operation and maintenance instruction plates, tags and labels should be maintained in legible condition.

16. The truck should be kept in clean condition to minimize fire hazards and facilitate detection of loose or damaged parts.

17. Checking the performance of the truck or attachments should be conducted in an authorized safe area.

18. Always use Yale replacement parts to be sure they are interchangeable with the original parts and are of a quality equal to that provided in the original equipment.

You should also be familiar with additional maintenance safety instructions contained in the following publications: 1.

ANSI B56.1-Safety Standard for Powered Industrial Trucks

This booklet can be obtained from: Society of Mechanical Engineers 345 E. 47th Street New York, NY 10017 2.

ANSI/NFPA 505-Type Designations, Area of Use, Maintenance and Operation of Powered Industrial Trucks

This booklet can be obtained from: National Fire Protection Assoc.

Batterymarch Park Quincy, MA 02269

Sheet 1: Operating Instructions 3.

Code of Federal Regulations Title 29, Chapter XVII, Section 1910.178 (OSHA) Powered Industrial Trucks

This booklet can be obtained from: Superintendent of Documents U.S. Government Printing Office Washington, D.C.

MOVING A DISABLED LIFT TRUCK Motorized hand trucks are not normally towed. If the drive motor or drive unit will not operate, make repairs at the location if possible. If the lift truck must be towed, tow the lift truck in the direction of the control handle, forks trailing.

Never attempt to tow the lift truck by fastening any towing device to the control handle. Carefully attach the tow chain completely around the motor compartment and battery compartment. Make sure the tow chain is installed on the lift truck so that the chain will not cause damage. Make sure the control handle is in the operating position to release the brake during towing (MPW, MLW and MPE trucks). Make sure the hand brake is released (MPC, MTR trucks). Steer the lift truck with the control handle while it is being towed. On the MPW, MLW and MPE lift trucks use one hand and walk to one side of the truck. Do not get between the towing vehicle and the lift truck.

WARNING: Be sure to stay clear of the tow chain, towing vehicle and the lift truck during the towing operation to prevent injury.

WARNING: Travel slowly and do not tow on grades. NEVER tow the lift truck faster than a normal walking speed. Always tow smoothly without sudden starts or stops.

WARNING: Until repairs are complete keep a tag on the control handle stating-DO NOT OPERATE. Remove the key.

HOW TO PUT A LIFT TRUCK ON BLOCKS

WARNING: Do not put the lift truck on blocks if the surface is not solid, even and level. Make sure that any blocks used to support the lift truck are solid, one-piece units. Put a block in front and back of the tires touching the ground to prevent movement of the lift truck.

WARNING: Do not raise the lift truck by attaching an overhead crane to areas that will be damaged. Some of these points are not designed to support the weight of the lift truck. The lift truck can be damaged or it can fall on someone causing serious injury. Attach the chain or sling to a support structure of the lift truck frame.

Sheet 1: Operating Instructions

Figure 1-16 - Blocking MPW, MLW and MPE Models MPW SHOWN, MPE AND MLW SIMILAR

HOW TO RAISE DRIVE TIRE 1.

Put blocks on both sides (front and back) of the load wheels to prevent movement of the lift truck.

2.

Use a special low clearance hydraulic jack, crane or another lift truck to raise the drive tire. Make sure that the jack, crane or other lift truck has the correct capacity rating. The capacity must equal at least 2/3 the weight of the lift truck including the battery. See the nameplate.

3.

Raise the lift truck only enough to suspend the drive tire. Install additional blocks on each side of the truck under the drive unit frame. See Figure 1-16 through Figure 1-18.

HOW TO RAISE LOAD WHEELS 1.

Put blocks on both sides (front and back) of the drive tire to prevent movement of the lift truck.

WARNING: Never raise the forks any higher than necessary to change the load wheels. Always raise both forks at the same time. Raising the forks too high or uneven can make the lift truck tip over and cause damage or possible injury.

2.

Use a hydraulic jack, crane or another lift truck to lift the forks. Make sure that the jack, crane or other lift truck has a capacity equal to at least half the weight of the lift truck including the battery. See the nameplate.

3.

Put blocks under the forks at the rear of the load wheel to support the lift truck. See Figure 1-16 through Figure 1-18.

Sheet 1: Operating Instructions

Figure 1-17 - Blocking MPC Models

Figure 1-18 - Blocking MTR Models

PRECAUTIONS FOR TRUCKS IN STORAGE Experience has taught that complications can arise as a result of improper handling of trucks during periods of storage. The main areas of concern are electric motors, hydraulic components and electric truck batteries. Electric powered trucks can best be protected by being operated for a short period of time each month.

Before placing any truck in storage, you must choose an area which is clean, dry and free from airborne contaminants.

Electric drive motors must be exercised to keep them free of rust and contamination caused by condensation built up over periods of inactivity. Operate the truck with the motor at its normal temperature for at least five minutes. This exercise period will also allow the transistor control to expel any moisture accumulation.

Prior to operating a truck each month, make a visual inspection for leaks or signs of deterioration. Take corrective action

Sheet 1: Operating Instructions immediately. Also, check the fluid level in the hydraulic system.

Electric trucks should be stored without batteries, therefore you will have to provide a fully charged battery for the exercise period.

When a truck is returned to service, it should be given the 200 hour inspection shown in the Recommended Schedule of Maintenance found in Section 2.

CAUTION: Do not use a battery charger as a power source for any reason. Damage to the transistorized controller could result from this practice.

All hydraulic cylinders should be cycled several times each month to keep the seals active and to coat the interior walls with oil.

Actuate each cylinder, in both directions, until the stops are reached. With the power off, actuate each control button to relieve hydraulic pressure. Forks are to be stored fully lowered. Coat any exposed portion of all cylinder rods with fresh high grade SAE 30 or 40 weight engine oil.

PRECAUTIONS FOR BATTERIES IN STORAGE Batteries should be placed on a wooden pallet and stored in a dry, moderately cool area. Lead acid batteries will slowly "self discharge" over a period of time due to their chemical make-up. This "self discharge" is due to a chemical reaction; therefore, that chemical reaction can be accelerated by heat resulting in a more rapid "self discharge". The rate of discharge can amount to an average of about 0.001 point drop in specific gravity per day. If the self discharge is left uncontrolled, excessive sulfating can occur which is difficult to reduce and may damage the plates. A discharged battery with a specific gravity of 1.100 will freeze at +18°F. A fully charged battery with a specific gravity of 1.280 will freeze at -87° The following procedure should be followed when placing a battery in storage or when not in operation for more than 30 days. a.

Give equalizing charge prior to placing new batteries in storage. Used batteries are to be fully charged and allowed to balance for approximately three more hours.

b.

If a greasy film forms on the top of a battery, it is acid and must be neutralized. Neutralize and clean with a solution of 16 ounces of baking soda in one (1) gallon of water.

c.

Store in a cool, dry location on a wooden pallet.

d.

Check each cell in the battery at least once every 30 days and boost charge when specific gravity falls below 1.240.

e.

Protect batteries from ambient contamination.

Battery chargers should be disconnected from the AC power source when not in use.

Sheet 2: User Support Information

USER SUPPORT INFORMATION Your investment in a Yale® industrial truck is important to you and to your Yale industrial truck dealer. You measure the return on your investment through the drivers who operate the trucks and the mechanics who service them safely and efficiently.

A "Guide to Lift Truck Use and Maintenance", which addresses lift truck safety in the workplace, good maintenance practices and training programs, is available from your Yale industrial truck dealer. Order manual #2020.

The following information and programs are intended to help you to achieve your investment objectives.

SERVICE PARTS ORDERING INSTRUCTIONS In order to avoid delay, unnecessary correspondence and to have your orders filled correctly, promptly and at the least possible expense, the following is the recommended procedure to use when ordering replacement parts.

Contact your authorized Yale industrial truck dealer and give him the following information: 1.

Your Purchase order number.

2.

Complete invoicing and shipping address.

3.

Specify the method of shipment, otherwise the least expensive method will be used.

4.

Correct part number(s) and description(s). Use your parts manual as a reference.

5.

Model and serial number of the truck.

TECHNICAL PUBLICATIONS Technical literature, with detailed information, is available at a nominal fee to assist users to effectively maintain Yale industrial trucks in a safe, useful condition. Parts Manuals with complete replacement parts identification, Service Maintenance Manuals which provide service and overhaul procedures and additional copies of this Operating Manual, can be obtained from your Yale industrial truck dealer.

PARTS MANUAL-MPW, MPE, MPC, MLW-1604

OPERATING MANUAL- MRW, MSW, MCW-1605 (5192838-06) To provide instructions for safely operating and servicing Yale industrial trucks, each truck is equipped with an Operating Manual.

The Operating Manual describes various operating techniques and safety warnings for the operator. The Operating Manual also contains a guide to safe maintenance practices and recommended schedules for maintenance.

If the Operating Manual is missing from any Yale industrial truck, it should be replaced. Replacement copies are available for a nominal fee from your Yale industrial truck dealer.

OPERATOR TRAINING Yale "Basic Operator Training" program helps industrial truck users increase materials handling productivity and safety through proper lift truck operation training and motivation. The Yale program is based upon real life experience-not theoretical concepts. We developed a "complete" program that is totally self-contained-incorporating the most modern instructional techniques, including elements of self-study, audio-visual support (both video and slides) and classroom study.

SERVICE TRAINING COURSES User and Yale industrial truck dealer service technicians can improve their technical ability for maintaining and repairing Yale Industrial Trucks and reduce down-time and cost by participating in Yale sponsored Service Training courses. A variety of

Sheet 2: User Support Information mechanical, electrical and electronic subjects are offered at published tuition rates. Courses are available at user and Dealer facilities in addition to regularly scheduled courses which are conducted at Yale Corporate Headquarters in Flemington, New Jersey.

SERVICE TRAINING MATERIALS Your own service training efforts are supported through a complete line of Yale Service Training materials. An index is available from your Yale industrial truck dealer which lists textbooks, audio-visual programs, films and their cost which will provide your trainer with everything necessary to conduct service training for your organization.

For additional information or assistance in obtaining these user support publications and programs, contact your Yale industrial truck dealer or the Yale Materials Handling Corporation, 15 Junction Road, Flemington, New Jersey 08822-9499.

Sheet 4: General Electric--Hand Held Controller

ELECTRICAL SYSTEM ELECTRICAL SYSTEM-GENERAL This section describes the electrical systems used on the motorized hand lift trucks. Procedures are outlined for the maintenance, adjustments and repairs that may be required when servicing these lift trucks.

The drive control for the Yale Motorized Hand Trucks is a Curtis Transistor Motor Controller, also known as a MOSFET or PMC system. The controller used in the different lift trucks covered in this manual will vary between models, and will also vary in the same models depending upon the voltage of the lift truck. Make certain to identify the controller before doing any work or testing of the electrical system. REFER TO THE PARTS MANUALS FOR THE PROPER CONTROLLER USED ON A SPECIFIC MODEL.

WARNING: Do not make repairs or adjustments unless you have both authorization and training. Repairs and adjustments that are not correct can create a dangerous operating condition. Do not operate a lift truck that needs repairs. Report the need for repairs to your supervisor immediately. If repair is necessary, put a "DO NOT OPERATE" tag on the control handle. Remove the key from the key switch.

Figure 3-1 - Drive Unit Compartment-MPE (Early Production) 1.

2.

3.

4.

5.

6.

CONTACTOR PANEL KEY SWITCH CONNECTOR FUSE, HYD. 200A., FU 1 CONTACTORS DRIVE MOTOR

Sheet 4: General Electric--Hand Held Controller 7. HORN 8. LIFT LIMIT SWITCH 9. HYDRAULIC UNIT 10. BRAKE LINKAGE 11. LIFT CYLINDER 12. DRIVE UNIT 13. CONTROLLER 14. LIFT LINKAGE 15. FUSE TRACT. 200A., FU-2 16. TERMINAL BLOCK (TB-2) 17. FUSE, CONT. 15A., FU-3 18. RELAY (CR-2) 19. RELAY (CR-1) 20. TERMINAL BLOCK (TB-1)

Figure 3-2 - Drive Unit Compartment-MPE (From S/N 57661 and up) 1.

2.

3.

4.

5.

6.

7.

8.

9.

IGNITION SWITCH BRAKE SYSTEM BATTERY CONNECTOR VARISTOR-LIFT CONTACTOR VARISTOR-SOLENOID VALVE WIRE HARNESS HYDRAULIC SYSTEM HORN SUPPRESSOR

Sheet 4: General Electric--Hand Held Controller 10. MOUNTING BRACKET 11. LIFT LIMIT SWITCH 12. CONTROLLER 13. CONTACTOR PANEL 14. DRIVE UNIT 15. BRAKE SWITCH 16. RELAY CR1 17. RELAY CR2 18. FUSE F1 19. FUSE F2 20. FUSE F3 21. FWD/REV CONTACTORS

CURTIS PMC TRANSISTOR CONTROLLER The description of the current flow in the electrical circuits in this section uses the "Conventional Theory of Current Flow". This theory describes the current as flowing from positive to negative. An electric lift truck uses an insulated electrical system. There is no common ground through the frame. Both the positive supply and the negative return currents flow through wires and cables. There must be a minimum resistance of 50,000 ohms between the electrical circuits and the frame of the lift truck.

The logic of the controller also checks the following functions: a.

Checks the temperature and gives both low and high temperature thermal protection to the controller.

b.

Electrically checks that an operator follows the correct starting sequence to help prevent unexpected operation. This function has been called "Static-Return-To-Off" (SRO).

c.

Electrically checks the traction circuit for certain malfunctions. This function prevents lift truck operation if a failure is sensed.

d.

Checks the current in the motor circuit and automatically decreases the motor voltage to reduce the current and prevent damage. The plugging circuit is also controlled for smoother operation.

Additional information showing how the motor controller is electrically connected in the lift truck is shown on the Wiring Diagrams and Schematics found at the rear of this section.

Sheet 4: General Electric--Hand Held Controller

Figure 3-3 - Drive Unit Compartment-MPW (Early Production) 1. CONTACTOR PANEL 2. KEY SWITCH 3. CONNECTOR 4. FUSE, HYD. 200A., FU 1 5. CONTACTORS 6. DRIVE MOTOR 7. HORN 8. LIFT LIMIT SWITCH 9. HYDRAULIC UNIT 10. BRAKE LINKAGE 11. LIFT CYLINDER 12. DRIVE UNIT 13. CONTROLLER 14. LIFT LINKAGE 15. FUSE TRACT. 200A., FU-2 16. FUSE, CONT. 15A., FU-3 17. RELAY (CR-2) 18. TERMINAL BLOCK (TB-1)

Sheet 4: General Electric--Hand Held Controller

Figure 3-4 - Drive Unit Compartment-MPW (From S/N 576820) 1. IGNITION SWITCH 2. BATTERY CONNECTOR 3. FWD/REV CONTACTOR 4. WIRE HARNESS 5. VARISTOR-SOLENOID VALVE 6. HYDRAULIC SYSTEM 7. SUPPRESSOR 8. HORN 9. VARISTOR-LIFT CONTROL 10. MOUNTING BRACKET 11. LIFT LIMIT SWITCH 12. BRAKE SYSTEM 13. BRAKE SWITCH 14. DRIVE UNIT 15. CONTROLLER 16. LIFT LINKAGE 17. RELAY CR1 18. FUSE FU1 19. FUSE FU2 20. FUSE F3

ELECTRICAL SYSTEM-GENERAL This section describes the electrical systems used on the motorized hand lift trucks. Procedures are outlined for the maintenance, adjustments and repairs that may be required when servicing these lift trucks.

The drive control for the Yale Motorized Hand Trucks is a Curtis Transistor Motor Controller, also known as a MOSFET or

Sheet 4: General Electric--Hand Held Controller PMC system. The controller used in the different lift trucks covered in this manual will vary between models, and will also vary in the same models depending upon the voltage of the lift truck. Make certain to identify the controller before doing any work or testing of the electrical system. REFER TO THE PARTS MANUALS FOR THE PROPER CONTROLLER USED ON A SPECIFIC MODEL.

Figure 3-5 - Drive Unit Compartment-MPC (Early Production) 1. CONTACTOR PANEL 2. KEY SWITCH 3. CONNECTOR 4. FUSE, HYD. 200A., FU 1 5. CONTACTORS 6. DRIVE MOTOR 7. HORN 8. LIFT LIMIT SWITCH 9. HYDRAULIC UNIT 10. BRAKE LINKAGE 11. LIFT CYLINDER 12. DRIVE UNIT 13. CONTROLLER 14. LIFT LINKAGE 15. FUSE TRACT. 200A., FU-2 16. FUSE, CONT. 15A., FU-3 17. TERMINAL BLOCK (TB-1)

Sheet 4: General Electric--Hand Held Controller

CURTIS PMC TRANSISTOR CONTROLLER The description of the current flow in the electrical circuits in this section uses the "Conventional Theory of Current Flow". This theory describes the current as flowing from positive to negative. An electric lift truck uses an insulated electrical system. There is no common ground through the frame. Both the positive supply and the negative return currents flow through wires and cables. There must be a minimum resistance of 50,000 ohms between the electrical circuits and the frame of the lift truck.

Figure 3-6 - Drive Unit Compartment-MPC (From S/N 576761) 1. IGNITION SWITCH 2. BATTERY CONNECTOR 3. FWD/REV CONTACTOR 4. BRAKE SYSTEM 5. VARISTOR SOLENOID VALVE 6. HYDRAULIC SYSTEM 7. SUPPRESSOR 8. HORN 9. VARISTOR-LIFT CONTACTOR 10. MOUNTING BRACKET

Sheet 4: General Electric--Hand Held Controller 11. LIFT LIMIT SWITCH 12. BRAKE SWITCH 13. DRIVE UNIT 14. CONTROLLER 15. LIFT LINKAGE 16. FUSE FU1 17. FUSE FU2 18. FUSE F3

WARNING: Do not make repairs or adjustments unless you have both authorization and training. Repairs and adjustments that are not correct can create a dangerous operating condition. Do not operate a lift truck that needs repairs. Report the need for repairs to your supervisor immediately. If repair is necessary, put a "DO NOT OPERATE" tag on the control handle. Remove the key from the key switch.

The logic of the controller also checks the following functions: a.

Checks the temperature and gives both low and high temperature thermal protection to the controller.

b.

Electrically checks that an operator follows the correct starting sequence to help prevent unexpected operation. This function has been called "Static-Return-To-Off" (SRO).

Figure 3-7 - Drive Unit Compartment-MTR (Early Production) 1.

2.

CONTACTOR PANEL KEY SWITCH

Sheet 4: General Electric--Hand Held Controller 3. CONNECTOR 4. CONTACTORS 5. DRIVE MOTOR 6. HORN 7. BRAKE LINKAGE 8. SUPPORT 9. DRIVE UNIT 10. CONTROLLER 11. TERMINAL BLOCK 12. FUSE,CONT. 15A., FU-3 13. FUSE, TRACT. 200A., FU-2 14. TERMINAL BLOCK (TB-1) c.

Electrically checks the traction circuit for certain malfunctions. This function prevents lift truck operation if a failure is sensed.

d.

Checks the current in the motor circuit and automatically decreases the motor voltage to reduce the current and prevent damage. The plugging circuit is also controlled for smoother operation.

Additional information showing how the motor controller is electrically connected in the lift truck is shown on the Wiring Diagrams and Schematics found at the rear of this section.

Principles of Operation A motor controller for an electric lift truck provides speed control to the traction motor by making a variation in the applied voltage. This controller uses solid-state electronic devices to permit efficient control of the applied voltage.

Figure 3-8 - Drive Unit Compartment-MTR (From S/N 991606)

Sheet 4: General Electric--Hand Held Controller 1. IGNITION SWITCH 2. BATTERY CONNECTOR 3. FWD/REV CONTACTOR 4. WIRE HARNESS 5. BRAKE LINKAGE 6. SUPPRESSOR 7. HORN 8. DRIVE UNIT 9. CONTROLLER 10. CONTACTOR PANEL 11. FUSE FU1 12. FUSE FU3 A motor controller must also generate a high current flow in the traction motor while keeping a low current draw from the battery. A battery is less efficient at a high current draw. A battery will not give all its electrical power at a high current draw.

The traction motor is a series wound motor that generates torque. This torque is proportional to the current moving through the motor. The speed of the motor is controlled by the voltage and the mechanical load connected to the motor. The motor will accelerate until the mechanical load compares equally to the torque. If the current through the motor is increased, the torque will increase. The increased torque will give a higher speed with the same mechanical load.

Figure 3-9 - Drive Unit Compartment-MLW 1.

IGNITION SWITCH

Sheet 4: General Electric--Hand Held Controller 2. FWD/REV CONTACTORS 3. BRAKE SYSTEM 4. RELAY 5. VARISTOR-LIFT CONTACTOR 6. VARISTOR-SOLENOID VALVE 7. WIRE HARNESS 8. HYDRAULIC SYSTEM 9. HORN 10. SUPPRESSOR, HORN 11. CONTROLLER 12. CONTACTOR PANEL 13. DRIVE UNIT 14. BUSS BAR (B*) 15. BUSS BAR (M*) 16. BUSS BAR (B*) 17. BUSS BAR (A2) 18. FUSE (FU1) 19. FUSE (FU2) 20. FUSE (FU3)

TRANSISTOR MOTOR CONTROLLER This motor controller controls the speed of the traction motor. The direction of rotation of the motor is controlled by the Forward/Reverse switch and contactors. See Figure 3-11 through Figure 3-13. The controller is sealed in an aluminum case and no parts can be repaired or replaced. The complete unit must be replaced if correct troubleshooting methods show that the unit is damaged.

External contactors are used to control the direction of rotation of the traction motor. Contactors are electrical switches that use an electromagnet to operate the power contacts of the switch. A small electric signal is used to energize the electromagnet to close the power contacts and control the large current flow needed for the motor circuit. The electromagnetic field in the coil moves the armature against spring pressure to close the power contacts. When the coil is deenergized, the spring pressure moves the armature and opens the contacts. When a spring holds the contacts of a switch open, the switch is called normally open (NO). If the switch spring holds the contacts of a switch closed, the switch is called normally closed (NC).

NOTE: In the following figures, the gray lines on the circuit lines show positive voltage with respect to battery negative. Slash lines show negative voltage with respect to battery positive. The line codes do not always indicate full battery voltage.

The gray tone is used only for the circuits being described. Some parts of the energized circuit are not shown with gray tones or slashes. The thick (bold) lines show the control circuits.

Contactors are used to energize and de-energize motors, but cannot control the speed. The transistor motor controller applies battery voltage in short, fast pulses to a DC motor to control the speed. How this circuit controls the speed of a motor with pulses is described in this section.

The direction and speed control operates the FWD/REV switch to energize the direction contactor. The control also supplies the speed input to the motor controller.

There are two contactors that control the direction of rotation of the traction motor. Each direction contactor has two sets of contacts on the same plunger assembly. Each contactor has a set of NO contacts and a set of NC contacts. When one set of contacts is closed, the other set must be open. This arrangement prevents a wrong sequence of closed contacts that could cause an open circuit. This arrangement of contactors also permits current flow through the motor field in either direction.

See Figure 3-12 and Figure 3-13. One set of contactors causes the motor armature to rotate in one direction. The other set of contacts causes the motor armature to rotate in the opposite direction. Other contactors used for control functions on the lift truck have one set of contacts because a forward and reverse operation is not required. An example is the hydraulic pump motor contactor.

Sheet 4: General Electric--Hand Held Controller

Figure 3-10 - Controller Wire (Control) and Cable (Power) Terminals 1. POWER TERMINAL 2. TERMINAL 2 3. TERMINAL 1 4. POWER TERMINAL 5. POWER TERMINAL 6. KEY SWITCH INPUT 7. F/R CONTACTOR OUTPUT 8. STATIC-RETURN-TO-OFF OR 1A 9. BRAKE OR EMERGENCY REVERSE 10. FORWARD INPUT 11. REVERSE INPUT 12. A2 POWER TERMINAL

Figure 3-1 - Basic Traction Motor Circuit 1.

2.

3.

4.

5.

BATTERY TRACTION MOTOR ARMATURE TRACTION MOTOR FIELD REVERSE CONTACTOR CONTACTS FORWARD CONTACTOR CONTACTS

Sheet 4: General Electric--Hand Held Controller 6.

FET'S SWITCH

Figure 3-2 - Current Flow Through the Field in the FORWARD Direction

Figure 3-3 - Current Flow Through the Field in the REVERSE Direction Basic Controller Operation This transistor motor controller has a power section and a logic section with solid-state electronic circuits that control the operation of a DC motor. The speed of DC motors is controlled by the average applied voltage. The higher the average applied voltage, the faster the motor will rotate. If a switch is put in the traction motor circuit (see Figure 3-4) and the switch is changed to OFF and ON quickly (see Figure 3-4) the traction motor will rotate. The speed of rotation increases as the time the switch is ON increases. The speed of rotation will decrease if the ON time decreases. OFF time will increase at the same time.

The speed of the motor can be controlled using this principle.

This controller uses an electronic device called a Field Effect Transistor (FET) to generate the rapid ON and OFF pulse times. It has no moving parts. The FETs are turned on and off by the logic circuits in the controller to act as the switch. Several power FETs are connected in parallel to carry the necessary motor current.

Field Effect Transistor (FET)

Sheet 4: General Electric--Hand Held Controller A FET is a solid-state device that operates like a very fast switch. A FET is a transistor that has an element called a gate. FETs are electronic devices that permit electricity to flow as long as there is a gate voltage. See Figure 3-4. Electricity flows easily from the input to the output. A FET will only permit current flow when there is a positive voltage at the input, a negative voltage at the output and a positive voltage applied to the gate. A FET will permit electricity to flow from the input to the source as long as there is the signal voltage at the gate. The FET's ON time is the same as the gate pulse ON time. Current flows as shown in Figure 3-4. The FET stops conducting when the signal voltage is removed from the gate.

When FETs are used as a switch: a.

The FETs are ON when the electric current flows through them (gate voltage applied).

b.

The FETs are OFF when the electric current cannot flow through them (no gate voltage).

Motor Circuit that Operates with Pulses A schematic that shows the controller and FETs in a traction circuit is shown in Figure 3-4. When a signal is applied to the gate of the FETs, the FETs are ON and current flows from the battery through the motor. When the gate signal is removed, the FETs are changed to OFF. The battery voltage is applied to the motor in pulses. The pulses of energy through the FETs to the motor are very fast (15,000 on/off cycles per second). The motor cannot follow each pulse, but the motor runs smoothly based on the average voltage generated by the ON and OFF times. The average motor voltage applied to the traction motor is shown in Figure 3-5. The length of the ON TIME of the pulses changes the average motor voltage. As the ON TIME of each pulse increases (OFF TIME decreases), the average motor voltage increases. This change in the ratio of ON TIME to OFF TIME of the pulses is called pulse width modulation.

The control circuit has an oscillator and a pulse width modulator. The oscillator generates a saw tooth waveform at a constant frequency of 15,000 cycles per second (15 kHz). The pulse width modulator uses this saw tooth waveform to generate a pulse output that can be smoothly changed from a full ON to a full OFF condition. This pulse output is used by the gate driver circuit for the high pulse currents needed to turn the FETs ON and OFF. The pulse width modulator controls the ON and OFF times of the FETs through the gate driver. The ratio of ON TIME to OFF TIME sets the average motor voltage and the motor speed. The accelerator potentiometer, at the speed control of the lift truck, produces a voltage that changes as the operator sets the speed of operation. This voltage is an input to the controller and the pulse width modulator. As the voltage changes with the selected speed, a direct change in the ratio of FET ON TIME to FET OFF TIME also occurs. The voltage for maximum speed changes the ratio to pulses with the maximum ON TIME, to produce a maximum average motor voltage. See Figure 3-5. The pulse rate (15 kHz) stays the same for all speeds.

Sheet 4: General Electric--Hand Held Controller

Figure 3-4 - Transistor Control 1.

2.

3.

4.

5.

6.

7.

8.

9.

BATTERY TRACTION MOTOR GATE DRIVE FET INPUT (+) FET OUTPUT (-) FET GATE (+) POSITIVE SUPPLY THROUGH MOTOR POSITIVE GATE SIGNAL NO GATE SIGNAL

Sheet 4: General Electric--Hand Held Controller

Figure 3-5 - Average Motor Voltage Induction Current from the Motor When a DC motor is controlled by a pulsed circuit, the magnetic field in the armature and field windings is continuously expanding and decreasing. The fields expand when voltage is applied (ON TIME) and decreases when the voltage is removed (OFF TIME). The voltage causes an increasing current flow through the windings to make the expanding magnetic field. When the voltage is removed, the decreasing magnetic field causes current to flow in the same direction through the windings. See Figure 3-6 and Figure 3-7. This expansion and decrease of the magnetic field is lost energy for doing work unless the controller is designed to use this energy. A Flyback Diode (sometimes called a "Freewheel" Diode) is in the controller circuit for this purpose.

BEGINNING CONDITIONS AS THE SWITCH IS CLOSED: 1. LARGE CURRENT FLOW FROM BATTERY THROUGH INDUCTOR. 2. INCREASING MAGNETIC FIELD GENERATES REVERSE VOLTAGE WITHIN INDUCTOR. 3. REVERSE VOLTAGE DECREASES CURRENT THROUGH INDUCTOR.

Sheet 4: General Electric--Hand Held Controller

CONSTANT CONDITIONS AFTER SWITCH IS CLOSED FOR A SHORT PERIOD OF TIME: 1. VOLTAGE AND CURRENT FLOW IS THE SAME IN ALL PARTS OF THE CIRCUIT 2. MAGNETIC FIELD IS CONSTANT

ENDING CONDITIONS AS THE SWITCH IS OPENED: 1.

DECREASING MAGNETIC FIELD GENERATES VOLTAGE WITHIN INDUCTOR. 2.

DECREASING MAGNETIC FIELD GENERATES CURRENT FLOW IN ORIGINAL DIRECTION. Figure 3-6 - Inductance

Figure 3-7 - Induction Motor Current

Sheet 4: General Electric--Hand Held Controller 1.

2.

3.

4.

5.

6.

BATTERY MOTOR ARMATURE MOTOR FIELD CONTROLLER FETS ( NOT "ON") FLYBACK DIODE

The Flyback Diode permits the current, from the decreasing magnetic field, to flow through the field and armature again to do work. The torque of a series DC motor is directly proportional to the amount of current flow through it. At slower speeds, the OFF times are longer. When the FETs are OFF, the decreasing magnetic field generates a voltage and current in the motor. This current is often called the "flyback current". The Flyback Diode permits the current to flow through the field and armature again to do work. At slower speeds, the motor current is part battery current and part "flyback current". There is less battery current used for the specific torque requirement. High current draw from the battery is to be avoided, if possible, because it is less efficient. At higher speeds, the OFF time is less, so that less induction current ("flyback current") is generated. Most of the motor current must come from the battery at higher speeds. However, the torque and current requirements are also usually less.

Plugging The plugging circuit is an added feature of the controller that provides smooth electrical braking when the operator wants to change the truck's direction of travel. The plugging feature also saves wear and tear on the drive tires and the drive unit gears.

Figure 3-8 - Plugging Current Circuit 1.

2.

3.

4.

5.

BATTERY MOTOR ARMATURE MOTOR FIELD CONTROLLER PLUGGING DIODE

Plugging occurs when the truck is traveling in one direction but the operator has switched the directional control to the opposite direction. In this instance, the motor armature is rotating in one direction while the magnetic forces of the fields are trying to force the armature the other way. This reaction generates current that is allowed to flow through a loop formed by the plugging diode in the controller. This generated current helps to slow the truck's speed magnetically in the same manner that compression in a gas engine will help to control the speed of an automobile when it is coasting. When a lift truck is in the plugging mode, the pulse rate of the controller must be maintained at a slow rate. To accomplish this the logic section of the controller signals that the truck is in a plugging mode and controls the oscillating rate. The oscillating rate pulses slowly no matter what position the directional control is in.

The plugging function of the controller is designed to allow the truck to travel 1 to 2 times the length of the lift truck after the truck is plugged before it reverses direction. The plugging distance is adjustable. Refer to ADJUSTMENTS, this section.

Sheet 4: General Electric--Hand Held Controller Plugging an electric lift truck is not a harmful practice, however, avoid plugging the drive motor when the drive wheel is jacked off the ground.

During plugging, the pulse rate is also decreased from 15 kHz to 1 kHz. The controller regulates the pulse widths of the pulses to the motor field for the correct amount of plugging. The accelerator circuit is also set to a low speed so that normal acceleration in the opposite direction will occur. The plugging adjustment on the controller changes the amount of motor field current allowed. The plugging adjustment can be changed as needed for an application.

Control Circuit The control circuit has operator inputs from the key and brake switches as well as the accelerator potentiometer. The circuit also has internal inputs from the power circuit for thermal protection, plugging sensing, low voltage protection and motor current (current limit). The control circuit uses these inputs to regulate the ON TIME pulses to the FETs for speed control, current limit and plugging strength.

Static-Return-To-Off (SRO) Function The control circuit includes a function to prevent the operation of the lift truck if the starting sequence is not correct. The function uses the inputs to the control circuit to make sure the operator is ready to operate the controls. The starting sequence is as follows: a.

Turn the key switch to the ON position. The key switch supplies the battery voltage to the brake switch.

b.

The operator must lower the steering handle to release the brake and close the brake switch on motorized hand trucks. Battery voltage is now supplied to the control circuit.

c.

Rotate the Direction/Speed control in the desired direction of travel to select travel direction and speed.

If Step (c.) is done before both steps (a.) and (b.) are complete, the lift truck will not move in either direction. The control circuit must get battery voltage through both the key and brake switches before it gets a speed signal from the accelerator potentiometer. If the starting sequence is not correct, the control circuit will not send a gate pulse to the FETs for traction motor current.

The SRO function also prevents the lift truck from going to full speed operation because of a malfunction in the accelerator circuit. An open circuit in the accelerator circuit is normally sensed as a full speed signal by the control card. If this malfunction exists, the SRO function will prevent the start of traction pulses. If the malfunction occurs during normal operation, the control circuit senses an accelerator potentiometer input of more than 7000 ohms (open circuit) and stops the traction pulses. The circuit will return to normal operation after the malfunction is repaired.

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors Thermal Protection Function

WARNING: Truck performance is reduced during Thermal Protection.

There is a sensor to sense the heat within the controller housing. If the controller gets too hot or too cold for correct operation, the control circuit will reduce the ON TIME of the pulses to decrease the current to protect the controller. The lift truck will still operate at a slower speed to permit it to be moved to a location out of the work area. The controller can then return to a normal operating temperature.

Low Voltage Protection Function

WARNING: Truck performance is reduced during Low Voltage Protection.

This function protects the controller and the battery. The controller will not operate correctly if there is not a minimum voltage from the battery. A 12 volt controller requires at least 9 volts to function properly while a 24 volt controller requires a minimum of 16 volts to function properly. The battery current drain increases as the battery voltage decreases. Too large a battery drain will damage the battery. If the battery voltage is low, the control circuit will decrease the ON TIME of the pulses to decrease the current drain. The battery can still operate the lift truck to move it for battery charging or replacement.

WARNING: Truck performance is reduced during Current Limit Protection.

The control circuit limits the traction motor current to a maximum value to protect the controller, motor and battery. The control circuit will decrease the ON TIME of the motor pulses to keep the motor current less than the maximum value. The maximum value is set by the manufacturer.

Power Circuit The power circuit is controlled by the control circuit. The complete power circuit is inside the controller and has the following parts: •

Field Effect Transistors

•

Flyback Diode

•

Plug Diode

•

Filter Capacitors

The parts in the power circuit cannot be replaced by users. Cables connect the battery and traction motor to the power circuit at the controller power terminals "B+", "A2", "M-" and "B-". All of the traction motor current flows through the power circuit of the controller.

ELECTRICAL SYSTEM-CHECKS

WARNING: Do not make repairs or adjustments unless you have both authorization and training. Repairs and adjustments that are not correct can create a dangerous operating condition. Do not operate a lift truck that needs repairs. Report the need for repairs to your supervisor immediately. If repair is necessary, put a "DO NOT OPERATE" tag on the control handle. Remove the key from the key switch.

WARNING: Disconnect the battery and separate the connector before opening the compartment cover or inspecting or repairing the electrical system. If a tool causes a short-circuit, the high current flow from the battery can cause an injury or parts damage.

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors NOTE: All checks, adjustments and repairs in the drive unit compartment are done with the compartment cover removed.

Remove the drive unit compartment cover to access the electrical components. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

WARNING: Some checks require the battery connected. Do not connect the battery until the procedure tells you to connect the battery. Make sure the drive wheel is raised to prevent truck movement and possible injury. Raise the drive wheel.

See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. The blocks must prevent the lift truck from falling and causing injury or damage.

NOTE: The correct meter polarity is necessary for the checks. The voltage checks are made between the point indicated in the troubleshooting chart and battery negative. Connect the meter negative to battery negative.

1.

Check the specific gravity of the battery. If the specific gravity is less than 1.260, the battery is not fully charged or is damaged. A fully charged battery has a specific gravity of 1.270-1.290. A discharged battery has a specific gravity of approximately 1.130.

2.

The Yale electric lift truck has a two-wire system. The frame must not be a common electrical path. Check for 50,000 ohms or more between each terminal of the battery connector for the lift truck and a clean connection on the frame. Remove any circuit paths between the controller and the frame of the lift truck. Carbon dust in a motor or other parts can cause a circuit path. Check for additional equipment that is causing a circuit path to the frame.

3.

Check for voltage between each terminal of the connector that fastens to the battery and a clean connection on the frame.

Normally there is some small voltage (less than 30% of the battery voltage) between the battery and the frame, even if the resistance is very high. A higher voltage can indicate a dirty battery or a battery with damage. Clean the battery and battery compartment as necessary.

4.

Visually check for parts or wires that are loose or damaged.

NOTE: Make an identification of any wires before you disconnect them. The wires must be connected correctly after checks or repairs.

SEQUENCE OF OPERATION-TRACTION CIRCUIT The sequence of operation describes a complete cycle of the transistor traction circuit. A sequence of the beginning conditions and the FET cycle is shown in Figure 3-9.

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors

Figure 3-9 - Sequence of Operation

TROUBLESHOOTING This section describes the most common faults that can occur in trucks with the CURTIS TRANSISTOR CONTROLLER. Follow the General Procedures to make sure that maintenance problems give the correct troubleshooting results. Follow the fault procedure that best describes the problem.

FAULT PROCEDURES The following pages have some common faults of these lift trucks and the procedures for finding the cause.

FAULT NUMBER 1

ONE DIRECTIONAL CONTACTOR WILL NOT CLOSE Possible Causes: •

Damaged (open) wire(s) in control circuit

•

Direction switch is damaged

•

Contactor coil is damaged

•

Transistor controller is damage at FWD or REV terminal.

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors

FAULT NUMBER 2

DIRECTIONAL CONTACTORS WILL NOT CLOSE FOR OPERATION IN EITHER DIRECTION

Possible Causes: • • • • •

Battery not connected Control fuse is damaged F/R switch is damaged Transistor controller is damaged Static Return to Off (SRO) invoked

• Key switch or brake switch is damaged • Traction reverse switch is damaged • Battery voltage is low • Wires in circuit are open

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors

FAULT NUMBER 3.

LIFT TRUCK WILL NOT MOVE IN EITHER DIRECTION. THE DIRECTIONAL CONTACTORS CLOSE NORMALLY. NO POWER WHEN DIRECTION/SPEED CONTROL IS MOVED.

Possible Causes: • Traction fuse is damaged • Open circuit between motor and contactors • Power contacts of direction contactor are damaged • Traction motor is damaged • Hi-Pedal Disable (HPO) invoked

• Accelerator potentiometer is damaged or needs adjustment • Damaged (open) traction motor cables • Transistor controller is damaged

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors

FAULT NUMBER 4.

DIRECTIONAL CONTACTORS CLOSE, LIFT TRUCK ACCELERATES TO FULL SPEED IMMEDIATELY.

Possible Causes: • Accelerator potentiometer damaged or needs adjustment

FAULT NUMBER 5.

• Transistor controller is damaged

TROUBLESHOOTING PMC CONTROLLER

Possible Causes: • Static Return to Off (SRO) invoked • PMC inputs not correct

• B* to M*short in wiring • Bad connection in 6 pin connector to PMC

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors TEST POINTS EXPECTED VALUE Disconnect six pin input to PMC and check the following at the wiring connector.

ADJUSTMENTS

WARNING: Do not make repairs or adjustments unless you have both authorization and training. Repairs and adjustments that are not correct can create a dangerous operating condition. Do not operate a lift truck that needs repairs. Report the need for repairs to your supervisor immediately. If repair is necessary, put a "DO NOT OPERATE" tag on the control handle. Remove the key from the key switch.

WARNING: Disconnect the battery and separate the connector before opening the drive unit compartment cover or inspecting or repairing the electrical system. If a tool causes a short-circuit, the high current flow from the battery can cause an injury or parts damage.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

WARNING: Some checks require the battery connected. Do not connect the battery until the procedure tells you to connect the battery. Make sure the drive wheel is raised to prevent truck movement and possible injury. Raise the drive wheel.

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. The blocks must prevent the lift truck from falling and causing injury or damage.

All checks, adjustments and repairs in the drive unit compartment are done with the drive unit compartment cover removed.

Remove the drive unit compartment cover for access to the electrical components. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION. The controller has three adjustments: Braking (plugging), Current Limit and Controlled Acceleration. The braking (plugging) adjustment adjusts how far the lift truck travels before reversing direction. The direction/speed control can be moved to the maximum speed position from stop or a slow travel speed. The controlled acceleration adjustment allows an adjustment to the maximum rate of acceleration. The current limit adjustment controls the motor current to a preset maximum.

If it is necessary to make any adjustments to the PMC perform the following steps: a.

Turn the key switch to the OFF position and disconnect the battery cable. Refer to the WARNING notes.

b.

Remove the compartment cover and discharge the capacitor.

c.

Remove the 3 mm (0.12 in) socket head screws to access the adjustment screws.

d.

Make adjustments using a small insulated screwdriver.

e.

Replace the socket head screws after the proper adjustments have been made. Install the compartment cover and connect the battery cable. Test operate the truck before returning the truck to service.

f.

Remove the potentiometer. Refer to STEERING HANDLE SWITCHES-REMOVAL.

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors

Figure 3-10 - Controller Adjustment Locations 1.

2.

3.

4.

TRANSISTOR CONTROLLER BRAKING (PLUGGING) ADJUSTMENT SCREW (CW = HARDER BRAKING) CURRENT LIMIT ADJUSTMENT SCREW (CW = HIGHER CURRENT) CONTROLLED ACCELERATION ADJUSTMENT SCREW (CW = FASTER ACCELERATION)

Plugging Adjustment Turning the braking (plugging) adjustment clockwise will increase the plugging effect and stop the lift truck in a shorter distance. Turning the adjustment counterclockwise will decrease the plugging effect. The traction motor brushes have a faster wear rate when the control is set for a shorter stopping distance (increased plugging). More heat is also generated in the traction motor at increased plugging. This adjustment should be set in the one o'clock position.

Acceleration Adjustment Turning the controlled acceleration adjustment clockwise will increase the acceleration rate. Turning the adjustment counterclockwise will give a slower rate of acceleration. The traction motor brushes have a faster wear rate when the control is set for an increased acceleration rate. More heat is also generated at increased acceleration. This setting should be set in the twelve o'clock position.

Current Limit Adjustment Turning the current limit adjustment clockwise will increase the current limit. This setting is factory set at the maximum 400 amps. Increasing this adjustment can cause damage to both the control or traction motor. The truck will also run at a higher than normal speed especially when it has no load. Lowering this adjustment can cause the truck to have limited starting torque and can cause the truck not to run at top speed when fully loaded. This setting should be set at the maximum adjustment

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors position.

Accelerator Potentiometer Adjustment

WARNING: Do not make repairs or adjustments unless you have both authorization and training. Repairs and adjustments that are not correct can create a dangerous operating condition. Do not operate a lift truck that needs repairs. Report the need for repairs to your supervisor immediately. If repair is necessary, put a "DO NOT OPERATE" tag on the control handle. Remove the key from the key switch.

NOTE: It is not normally necessary to remove and disassemble all the components that make up the control section of the steering handle to replace a damaged part. Do only the steps necessary to replace the damaged parts.

1.

Move the key to the OFF position. Disconnect the battery.

2.

Remove the four corner screws and washers retaining the top cover assembly to the base of the control handle. See Figure 3-13.

NOTE: The two center screws retain the mounting bracket assembly to the base.

3.

Hold the reversing button so that it does not fall. Carefully lift the top cover assembly off the base and remove the auto reverse actuator, springs and plunger.

4.

Make certain all wires are identified before disconnecting them from the switches. Disconnect both the connector to the potentiometer and the connector to the lift, lowering, horn and auto reversing switches.

5.

Use an ohmmeter (RX100 scale) to test the potentiometer. Connect the ohmmeter to the potentiometer connector. The ohmmeter should read greater than 3300 ohms when the control lever is in neutral. Move the control lever to the forward, then to the reverse directions. The meter reading should drop to less than 100 ohms at maximum travel in both directions. To center the potentiometer, loosen the set screws retaining the gear on the potentiometer. Use a screwdriver to rotate the potentiometer shaft. Adjust slowly until the potentiometer reading is approximately 3300 ohms. Rotate the potentiometer shaft clockwise, then counterclockwise to locate the midpoint of the potentiometer element. Tighten the set screws. Make certain the controls are in neutral. Recheck the potentiometer reading. The potentiometer is centered at this time. If the correct readings cannot be obtained, the potentiometer must be replaced.

Figure 3-11 - Potentiometer Gear Installation 1.

2.

3.

4.

5.

POTENTIOMETER GEAR SET SCREW ADJUSTMENT SLOT ROLL PIN SPUR GEAR

6.

Remove the potentiometer. Refer to STEERING HANDLE SWITCHES-REMOVAL.

7.

Install a new potentiometer. Refer to STEERING HANDLE SWITCHES-INSTALLATION.

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors 8.

Check the reading of the potentiometer.

9.

Connect the two connectors.

10. Align the plunger, springs and reversing switch actuator and both the top cover and base. Install the four screws and washers to retain the cover to the base.

11. Connect the battery, turn the key to the ON position and test operate the lift truck before returning the truck to service.

REPAIRS

WARNING: Do not make repairs or adjustments unless you have both authorization and training. Repairs and adjustments that are not correct can create a dangerous operating condition. Do not operate a lift truck that needs repairs. Report the need for repairs to your supervisor immediately. If repair is necessary, put a "DO NOT OPERATE" tag on the control handle. Remove the key from the key switch.

WARNING: Disconnect the battery and separate the connector before opening the compartment cover or inspecting or repairing the electrical system. If a tool causes a short-circuit, the high current flow from the battery can cause an injury or parts damage.

All checks, adjustments and repairs in the drive unit compartment are done with the compartment cover removed. Remove the drive unit compartment cover to access the electrical components. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

WARNING: Some checks require the battery connected. Do not connect the battery until the procedure tells you to connect the battery. Make sure the drive wheel is raised to prevent truck movement and possible injury. Raise the drive wheel.

See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. The blocks must prevent the lift truck from falling and causing injury or damage.

Controller Replacement Make an identification and disconnect the wires and cables from the controller. Remove the mounting screws and remove the controller. Apply a thin coating of silicone grease (Yale Part Number 5042232-39) on the bottom of the replacement controller. Install the replacement controller on the lift truck. Connect the wires and cables to the same terminals as identified during the removal procedure.

CONTACTORS Contactors are switches, controlled by electromagnets, that close and open a power circuit. The controller has internal electronic drivers. The electronic drivers control the current to the coils of the electromagnets for the contactors. The electromagnetic field in the coil moves the armature against spring pressure to close the contact. When the coil is deenergized, the spring pressure moves the armature and opens the contacts. When a spring holds the contacts of a switch open, the switch is called normally open (NO). If a spring holds the contacts of a switch closed, the switch is called normally closed (NC).

The contactor contacts are made of special silver alloy. The contacts will normally look black and rough from normal operation. This condition does not cause problems with the operation of the lift truck. Cleaning is not necessary. DO NOT USE A FILE ON THE CONTACTS. DO NOT LUBRICATE THE CONTACTS. Replace the contacts when the silver alloy is worn away to the base support metal.

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors The "FORWARD" and "REVERSE" contactor assembly controls the direction of current flow through the traction motor.

The contactor is a heavy-duty switch that opens and closes the power circuit. The traction circuit has a "FORWARD" and "REVERSE" contactor assembly. Each contactor assembly has the following parts: two sets of normally open (NO) contacts, two sets of normally closed (NC) contacts and a coil. The coil is an electromagnet that moves the NO contacts to the closed position against spring pressure. The coil is in the control circuit. The contactor tips are in the traction circuit. A suppressor is part of each coil.

When a contactor coil is energized, the normally open (NO) contacts close and the normally closed (NC) contacts open. Current flows through the traction motor field in one direction when the "FORWARD" contactor is energized and in the other direction when the "REVERSE" contactor is energized. This action gives direction control to the traction motor. The contacts normally have a long service life because the current flow through the contacts is stopped before the contacts open. The FETs are OFF before the contactor coil is deenergized.

Testing Contactors

WARNING: Parts of this procedure requires working on the lift truck with full electrical current present. Do not wear any rings, a watch or any other jewelry while working around the contactor panel. When manually closing a contactor with the power connected, use a properly insulated tool.

1.

Block the lift truck so that the drive wheels are off the floor. See Section 1-HOW TO PUT THE LIFT TRUCK ON BLOCKS. Make certain that the hydraulic controls are in the neutral position.

2.

Remove the drive unit compartment cover. See Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

CAUTION: Never operate the traction motor at full speed for more than a few seconds without a load when the drive wheels are off the floor. A series wound DC motor will continue to accelerate indefinitely until it exceeds its designed maximum rpm, at which point it will self-destruct.

3.

Check the condition of the battery. If it is not fully charged, charge or replace the battery with a fully charged battery before continuing.

4.

Visually check to see if the contactor closes when the circuit is energized. If the contactor closes, skip to Step 9. If the contactor does not close, proceed to Step 5.

5.

Check the contactor for loose, broken or corroded connections at the contactor.

6.

Check the mechanical function of the contactor. Use an insulated tool, such as an electricians screwdriver to manually close the contactor tips. Check for looseness or binding of the moving parts of the contactor. The parts should move freely, but the parts must not be so loose that the movement is sloppy.

7.

Visually check the tips for pitting, burning or wear.

8.

Disconnect the coil wires. Check the forward or reverse contactor coil with an ohmmeter. A suppressor diode with a resistor in series is part of the coil. The diode will cause the ohmmeter to indicate a difference in resistance in one direction.

Reverse the probes of the ohmmeter to the opposite terminals and measure the resistance. Use the highest resistance indication. Replace the coil if the resistance readings are a short-circuit in both directions or if there is an open circuit in both directions. Make sure the coil wires are connected again to the correct terminals.

Test the contactor coils using an ohmmeter.

The forward and reverse contactors are located on the contactor panel in the drive unit compartment. When testing the coils for the forward and reverse contactors the ohmmeter should read 18 ohms*10%.

The lift and lower contactor is located on the hydraulic pump motor in the drive unit compartment. When testing the coils for the lift and lower contactors the ohmmeter should read 50 ohms *10%.

9.

If the contactor closes but the truck does not work properly, check the electrical function of the high current section of the contactor (the tips and buss bars). With the lift truck battery connected and all switches closed, connect a volt ohmmeter across the high current terminals of the contactor.

Set the high voltage scale of the meter to the lowest range higher than battery voltage (50 volts for a 36 volt battery, etc.). On

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors forward and reverse contactors, with the contactor open, a reading of zero volts should be obtained. As the contactor closes, the meter should jump then immediately drop to zero or close to zero. This is the voltage drop across the contactor. On pump contactors, read the voltage across the contactor with the tips open. Battery voltage should drop to zero or near zero as the tips close.

A high voltage drop (2 volts or more) across the tips indicates a poor contact or high resistance. Check for burned or worn tips, incorrect size or mismatched tips and for an incorrect gap setting on contactors with adjustable point gaps.

Contactor Replacement NOTE: Make an identification of any wires before you disconnect them. The wires must be connected correctly after checks or repairs.

Make sure the battery is disconnected and the capacitor in the controller is discharged. The correct procedure to discharge the capacitor is described in the WARNING at the beginning of this section. If the lift truck has an EE rating, remove the cover of the contactor box for access to the contactor terminals. Make an identification of the wires and cables and disconnect them from the contactor assembly. Remove the mounting screws and replace the contactor assembly. Install the wires and cables as removed. Install the cover of the contactor box on EE units.

Contactor Component Replacement NOTE: If both the contacts and coil of a contactor will be replaced, replace the complete contactor as described in Contactor Replacement. Do only the parts of the procedure necessary to replace the damaged parts you are replacing.

NOTE: All of the contacts for each contactor must be replaced at the same time if any contact needs replacing.

NOTE: The numbers in parenthesis of the following procedure refer to the item numbers in Figure 3-12.

1.

Remove the contactor as described in CONTACTOR REPLACEMENT.

2.

Make an identification of the buss bars (2) for correct installation. Remove the buss bars and nuts that fasten to the fixed contacts.

Figure 3-1 Forward and Reverse Contactor Assembly NOTE: THE POWER CONNECTIONS FOR THE FIXED CONTACTS CAN BE DIFFERENT THAN SHOWN 1.

CAPSCREW

Sheet 5: Adjustment, Fault Finding, Checks, and Contactors 2. BUSS BAR 3. COVER 4. SPRING 5. FIXED CONTACTS 6. PLUNGER ASSEMBLIES AND MOVABLE CONTACTS 7. COVER BASE 8. COIL AND FRAME 9. MOUNT BRACKET 10. ARMATURE CAP 1.

Remove the two screws (1) that fasten the covers for each contactor. Remove the cover (3) of each contactor. Do NOT lose the plunger springs (4).

2.

Replace the four fixed contacts (5) in the contactor covers.

3.

Remove the two plunger assemblies and movable contacts (6) and replace the three fixed contact bars (5). Replace the contacts of the plungers.

4.

If a coil will be replaced, remove the cover base (7). Remove the screws that fasten the coil frame (8) to the mount bracket (9). Remove the coil and frame. Remove the bushing part of the plunger (6) and the armature cap (10) from the coil.

Install these parts on the replacement coil.

5.

Install the coil and frame on the mount bracket.

6.

Install the cover base, fixed contact bars and plungers on the coil frame. Make sure both springs are on both plungers.

7.

Install the covers and electrical bars on the covers as removed during disassembly.

8.

Install the contactor assemblies on the lift truck as described in CONTACTOR REPLACEMENT.

9.

Install the contact carrier (6), the lower fixed contact bars (7) and the lower clamps (8).

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting FUSES

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

The motorized hand trucks use a single 15 amp fuse for the control circuit, and 200 amp fuses for both the hydraulic pump motor and the drive motor. The fuses are located on the contactor panel. Remove and replace as required.

Table 3-1 - Fuses If it cannot be determined visually that any of the fuses have failed, check for continuity using an ohmmeter. To replace either FU-1 or FU-2 loosen the capscrews retaining them.

Install a new fuse and tighten the capscrews. FU-3 is retained by a fuse holder. Make certain that any replacement fuse is of the right amperage before installation.

RELAYS

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

NOTE: No relays are used on the MPC or MTR models.

The MPW60-80 uses one relay. The function of the relay is for automatic reversing. The automatic reversing relay is used to lock out the ability of the lift truck to travel toward the operator after the traction reverse button is depressed. The relay may be reset by moving the control handle to the full up or down position.

Two relays are used on all MPE 060-080 motorized lift trucks. The function of the relays is for automatic traction reversing and for fast speed. The relay is used to lock out the ability of the lift truck to travel toward the operator after the traction reverse button is depressed. The relay may be reset by moving the handle to the full up or down position. The fast speed relay will increase the truck speed when the fast speed button on the handrail is depressed. To discontinue use of the fast speed button, return the directional/speed control to neutral. A third relay is used when the optional pick handle is furnished.

Test the traction reverse relay coil using an ohmmeter and the charts shown. Perform test with the wires disconnected from the relay contact terminals. If a reading other than those listed in Table 3-2 is obtained, replace the relay.

Table 3-2 - Auto Reverse Relay Coil CR-1 MPE, MLW and MPW Only Check the relay contacts by energizing the relay coil. Supply battery + to relay terminal 11 and battery - to relay terminal 10 on the traction reverse relay. If a reading other than those listed in Table 3-3 is obtained, replace the relay.

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting

Table 3-3 - Auto Reverse Relay Contacts CR-1 MPE, MLW and MPW Only Test fast speed relay coil using an ohmmeter and the chart shown. Perform test with the wires disconnected from the relay contact terminals. If a reading other than those listed in Table 3-4 is obtained, replace the relay.

Table 3-4 - Fast Speed Relay Coil CR-2 MPE Only Check the relay contacts by energizing the relay coil. Supply battery*to relay terminal 8 and battery ** to relay terminal 7 on the fast speed relay. If a reading other than those listed in Table 3-5 is obtained, replace the relay.

Table 3-5 - Fast Speed Relay Contacts CR-2 MPE Only Test pick handle relay coil using an ohmmeter and the chart shown. Perform test with the wires disconnected from the relay contact terminals. If a reading other than those listed in Table 3-6 is obtained, replace the relay.

Table 3-6 - Pick Handle Relay Coil CR-3 MPE Only Check the relay contacts by energizing the relay coil. Supply battery*to relay terminal 8 and battery** to relay terminal 7 on the pick handle relay. If a reading other than those listed in is Table 3-7 obtained, replace the relay

Table 3-7 - Pick Handle Relay Contacts CR-3 MPE Only

BRAKE SWITCH

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting Removal and Installation

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

Refer to Section 5-BRAKE SYSTEM for access to the brake switch. Check the brake switch for continuity. If the brake switch must be removed, disassemble the leads from the switch. Make certain that the wires have been identified before removal. Remove the nut retaining the switch to the bracket. Remove the switch.

Position the switch in the bracket and install the nut on the switch to retain the switch to the bracket. Install the wires to the switch.

Connect the battery. Move the brake handle to check that the brake switch closes when the brake is released and opens when the brake is engaged. The brake switch is normally open until the control handle is moved to the operating position. Refer to Section 5-BRAKE ADJUSTMENT to properly adjust the brake switch.

HEIGHT LIMIT SWITCH Removal and Installation The height limit switch is located in the drive unit compartment on the right side of the lift truck on all models except the MTR. The MTR does not require a height limit switch because it has no hydraulic system. The function of the height limit switch is to prevent the hydraulic pump from running against relief after the hydraulic cylinder has reached the maximum extend position by cutting off power to the solenoid.

Check the height limit switch for continuity. If there is no continuity the switch must be replaced. Make certain the leads are properly identified before they are removed. Disconnect the leads to the switch. Remove the two capscrews, lockwashers and nuts retaining the switch to the frame.

Align a new switch with the holes in the frame and install the capscrews, lockwashers and nuts. Connect the leads to the switch.

Connect the battery and test operate the lifting mechanism to determine if the switch is operating properly. The switch is normally closed until the forks reach the maximum height which is 235 mm (9.25 in).

STEERING HANDLE SWITCHES Removal

WARNING: Do not make repairs or adjustments unless you have both authorization and training. Repairs and adjustments that are not correct can create a dangerous operating condition. Do not operate a lift truck that needs repairs. Report the need for repairs to your supervisor immediately. If repair is necessary, put a "DO NOT OPERATE" tag on the control handle. Remove the key from the key switch.

NOTE: It is not normally necessary to remove and disassemble all the components that make up the control section of the steering handle to replace a damaged part. Do only the steps necessary to replace the damaged parts. See Figure 3-2.

1.

Move the key to the OFF position. Disconnect the battery. Remove the key from the key switch.

2.

Remove the four corner screws (37&40) and lockwashers (36) retaining the top cover assembly (4) to the base (41) of the control handle.

NOTE: The two center screws (39) and lockwashers (38) retain the travel switch assembly to the base.

3.

Hold the traction reversing switch actuator (1) so that it does not fall. Carefully lift the top cover assembly (4) off the base and remove the reversing switch actuator, springs (2) and plunger (3).

4.

Disconnect both the connector to the potentiometer (15) and the connector to the horn, auto reversing, lift and lower

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting switches (10). Make certain all wires are identified before disconnecting them from the switches.

NOTE: The horn, auto reversing lift and lower switches, located in the top cover assembly may be tested for continuity without disassembly of the top cover assembly. Make certain that the harness is disconnected when testing for continuity.

Figure 3-2 - Control Head Switches 1. ACTUATOR 2. SPRING 3. RUBBER STOPPER 4. TOP COVER 5. ACTUATOR 6. ACTUATOR 7. ACTUATOR 8. SPRING 9. SWITCH RETAINER 10. SWITCH 11. SWITCH SUPPORT 12. CAPSCREW 13. LOCKWASHER

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting 14. CAPSCREW 15. SWITCH ASSEMBLY 16. POTENTIOMETER 17. STANDOFF 18. NUT PLATE 19. INSULATOR 20. SWITCH 21. SPACER 22. SET SCREW 23. SPUR GEAR 24. CAPSCREW 25. MOUNTING BRACKET 26. CAPSCREW 27. CONTROL LEVER 28. SET SCREW 29. BUSHING 30. TORSION SPRING 31. CAM 32. ROLL PIN 33. SHAFT 34. SPUR GEAR 35. ROLL PIN 36. LOCKWASHER 37. CAPSCREW 38. LOCKWASHER 39. CAPSCREW 40. CAPSCREW 41. BASE 42. COVER 43. COVER 44. BRACKET (OPTIONAL) 45. CAPSCREW (OPTIONAL) 46. RESISTOR (OPTIONAL) 47. LOCKWASHER (OPTIONAL) 48. NUT (OPTIONAL) 5.

Test the switches (10&20) for continuity. Visually inspect the travel switches for broken roller or broken springs. Replace any switch found to be damaged.

NOTE: The travel switches (20) may be replaced individually. It is not necessary to disassemble the mounting bracket from the base only to replace the travel switches. Other than the potentiometer, travel switches and control levers the components attached to the mounting bracket are not serviceable items.

6.

Remove the screws (24&26), nut plate (18), standoff (17), spacer (21) and insulators (19) to disassemble the forward and reverse switches (20) from the mounting bracket.

7.

To remove the control levers (27), remove the set screws (28) retaining the levers to the shaft.

8.

Disassemble the mounting bracket from the base by removing the two screws (39) and lockwashers (38).

NOTE: If the accelerator potentiometer is removed, the potentiometer MUST be adjusted during assembly. See ACCELERATOR POTENTIOMETER ADJUSTMENT 9.

Remove the set screws (22) retaining the potentiometer spur gear (23) and remove the gear. Remove the nut and lockwasher, then remove the potentiometer from the mounting bracket.

10. To remove the shaft from the control head arms. Disassemble the capscrews, washers, lockwashers and handle grips from the shaft. Refer to Section 6-CONTROL HANDLE HEAD-REMOVAL. 11. Disassemble the top cover assembly by removing the retaining screws (12&14) and lockwashers (13). Be careful not to lose the springs (8), covers (42&43) or actuators (5,6&7) when removing the switch assembly from the cover assembly.

Remove the switch retainer (9). The switch retainer is held in position with four spring loaded arms that are part of the switch support (11).

12. Remove the switches (10). Remove the actuators (5,6&7) or covers (42&43) and springs (8) from the steering handle cover.

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting Installation 1.

Install the horn and traction reversing switches in the switch support. Connect the wires to the proper switches.

2.

Assemble the switch retainer to the switch support. Install the actuators, covers and springs in the steering control cover.

Align the switch assembly and cover and install the four screws to retain the switch assembly and cover assembly.

Make certain that the reversing switch is located properly in the switch support before mating the two assemblies.

NOTE: These checks require a volt ohmmeter with a meter movement. Most digital meters will not operate correctly for some of these checks. Specific checks require additional equipment.

3.

Install the handle grips onto the shaft. Align the shaft assembly with the control handle arms and install the capscrews, washers and lockwashers to retain the shaft assembly.

4.

Install the control levers on the shaft and install the set screws to retain the levers to the shaft.

5.

Install the potentiometer in the mounting bracket. Install the lockwasher and nut on the opposite side. Install the gear on the potentiometer shaft using the two set screws. Make certain that the potentiometer gear and the sector gear on the mounting bracket are properly engaged. See NO TAG. The gears must be free to rotate through full travel and return to neutral when the control lever is released. Adjust the potentiometer, see ACCELERATOR POTENTIOMETER ADJUSTMENT.

6.

Align the reverse and forward switches, insulators, standoff, spacer and nut plates with the mounting bracket.

Apply adhesive sealant HCE-66 to the capscrews. Install the capscrews and tighten to 0.34-0.45 N*m (3-4 lb. in) torque.

7.

Attach the mounting bracket to the base using the two screws and lockwashers.

8.

Connect the two connectors.

9.

Align the plunger, springs and auto reverse actuator and both the top cover assembly and base. Install the four screws and washers to retain the cover to the base.

10. Connect the battery, install the key, turn the key to the ON position and test operate the lift truck before returning the truck to service.

PICK ASSIST SWITCHES-MPE (OPTIONAL) Removal

WARNING: Do not make repairs or adjustments unless you have both authorization and training. Repairs and adjustments that are not correct can create a dangerous operating condition. Do not operate a lift truck that needs repairs. Report the need for repairs to your supervisor immediately. If repair is necessary, put a "DO NOT OPERATE" tag on the control handle. Remove the key from the key switch.

NOTE: There are two switches located under the grip handle on each side of the pick handle. The two switches are wired in a series and both switches must be replaced if one switch fails. The following information is to remove and replace the switches on one side of the pick handle. Test the switches for continuity. If there is no continuity, replace the switches.

1.

Move the key to the OFF position. Disconnect the battery. Remove the key from the key switch.

2.

Remove the two capscrews and lockwashers that retain the grip cover to the pick handle arm. Remove the grip cover. See Figure 3-3.

3.

Remove the four corner screws Figure 3-2 (37&40) and lockwashers (36) retaining the top cover assembly (4) to the base (41) of the control handle.

NOTE: The two center screws (39) and lockwashers (38) retain the travel switch assembly to the base.

4.

Hold the auto reversing switch actuator (1) so that it does not fall. Carefully lift the top cover assembly (4) off the base and remove the reversing switch actuator, springs (2) and plunger (3).

5.

Locate where the pick handle switches are spliced in the control handle. Tag the wires for identification. Disconnect the wires to the switches that are to be removed.

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting 6.

Remove the two capscrews and lockwashers retaining the switch and bracket to the pick handle arm. Remove the switch from the bracket by removing the hex. nut and lockwasher.

7.

Remove the two capscrews and lockwashers retaining the end guard, button, spring and switch.

Installation 1.

Connect the lead wires furnished with the new switches to the existing splice in the control handle. Carefully run the wires from the control handle to the pick handle arm.

2.

Install the bottom switch in the bracket using a lockwasher and hex. nut. Install the bracket and switch on the pick handle arm using the two capscrews and lockwashers.

3.

Align the upper switch, spring, button and end guard in the pick handle. Install the two capscrews and lockwashers to retain the components to the pick handle arm.

4.

Align the plunger, springs and auto reverse actuator and both the top cover assembly and base. Install the four screws and washers to retain the cover to the base of the control handle.

5.

Align the grip cover with the pick handle arm. Make certain that the wiring to the switches will not interfere with the movement of the grip cover. lnstall the two capscrews and lockwashers to retain the grip cover to the pick handle arm.

6.

Connect the battery, install the key, turn the key to the ON position and test operate the lift truck before returning the truck to service.

Figure 3-3 - Pick Handle Switch Installation 1. PICK HANDLE ARM 2. COVER GRIP 3. CAPSCREW 4. LOCKWASHER 5. CAPSCREW 6. BRACKET 7. SWITCH 8. CAPSCREW 9. SWITCH 10. SPRING 11. BUTTON 12. END GUARD

MOTOR MAINTENANCE-GENERAL

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting This portion of the electrical section describes disassembly and assembly, brush replacement, inspection and checks for malfunction of DC motors. Inspect the commutator and brushes every 200 hours of operation. The commutator is the rotating electric connection between the armature and the electric power supplied by the battery. Brushes made of carbon compounds slide on the rotating commutator and are the path for electricity from the battery to the commutator and the armature. The maintenance of the commutator and the brushes is important to the good operation of a DC motor.

Drive motors and hydraulic pump motors are similar in design. The hydraulic pump motors are smaller than the drive motors, but the disassembly and maintenance of these motors are similar.

Figure 3-4 - Drive Motor

BRUSH AND COMMUTATOR INSPECTION

WARNING: Put blocks under each side of the truck under the drive unit frame. Position blocks on both sides of the load wheels. The blocks must prevent the lift truck from falling and causing injury or damage.

1.

Raise the drive wheel off the floor. Block the lift truck. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. Disconnect the battery.

2.

Remove the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

3.

Discharge the capacitor in the transistor controller.

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting 4.

If used, remove the brush covers to the motor. Wear eye protection. Use a vacuum cleaner or compressed air to remove dirt and "brush dust" from the commutator area.

NOTE: Vacuum cleaning, when possible, is the recommendation of manufacturers of electric motors. The use of compressed air can send dirt particles into the bearings and other areas of the motor that can cause possible damage.

5.

Visually inspect the commutator surface. Refer to Figures 3-20 through 3-28. The commutator wears slowly in normal service. The mica must be cut below the surface of the commutator bars after a long service period or after a commutator has been turned in a lathe. Carefully rotate the armature. DO NOT damage the commutator if you use a tool to rotate the armature.

6.

Inspect the white or gray insulation (mica) between the commutator bars. The mica must not touch the brushes or the brushes will wear very rapidly.

7.

Install the brush covers, when used and the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

8.

Connect the battery. Lower the truck to the floor. Test operate the motorized hand truck before returning the truck to service. Normal Commutator Service

A commutator that has been in service will have a smooth and polished surface with a darker brown color where it rotates under the brushes. A variation of color on the commutator surface between light brown and darker brown is normal. This surface condition is the lubrication between the commutator and the brushes. The brushes will wear rapidly if this surface condition does not develop during the first six to ten hours of operation after a commutator with a new surface is installed.

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting Figure 3-5 - Normal Commutator Surfaces Commutator Problems Commutator problems and motor problems are shown in Figure 3-6 through Figure 3-14. Refer to COMMUTATOR REPAIRS.

Figure 3-6 - Commutator Problems Heavy streaks and fine grooves indicates the beginning of damage to the commutator.

Possible Causes: •

Operation of the motor in dirty and abrasive conditions

•

Continuous operation of a motor with a light load

•

Brush pressure is too low

•

Worn brushes

Figure 3-8 - Commutator Problems Grooves and lines that have followed the heavy streaks and fine grooves shown in Figure 3-7. The armature must be removed from the motor so that the commutator can be repaired. A commutator with this conditions will cause the brushes to wear rapidly.

Possible Causes: •

Operation of the motor in dirty and abrasive conditions

•

Continuous operation of a motor with a light load

•

Brush pressure is too low

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting •

Worn brushes

Figure 3-9 - Commutator Problems Grooves that are the width of the brushes.

Possible Causes: •

Operation of the motor in dirty and abrasive conditions

•

Wrong type of brushes for this motor and operation

•

Brush pressure is too high

Figure 3-10 - Commutator Problems A condition called "copper drag" occurs when copper from the commutator bar is pulled into the slot between the commutator bars. This condition will cause a short-circuit between the commutator bars if it is not corrected. The brushes will wear rapidly.

Possible Causes: •

Operation of the motor in dirty and abrasive conditions

•

Wrong type of brushes for this motor and operation

•

Brush pressure is wrong (too high or too low.)

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting

Figure 3-11 - Commutator Problems Electrical burns on commutator bars on opposite sides of the commutator.

Possible Causes: •

Open armature winding

•

Motor has been stalled

Figure 3-12 - Commutator Problems Copper wears rapidly at at the edge of the commutator bars.

Possible Causes: •

Operation of the motor on dirty and abrasive conditions

•

Wrong type of brushes for this motor and operation.

Sheet 6: Relays, Switches, Motor and Brush Troubleshooting

Figure 3-13 - Commutator Problems 1.

Flashover causes burning of ends of commutator bar.

2.

Open circuit in winding vauses deep burring of adjacent commutator bars.

3.

Overheating causes damage to varnish insulation.

Possible Causes: •

Motor has been too hot. Wrong lift truck for the application

•

Motor has been stalled

•

Open armature winding

•

Open field coil

Figure 3-14 - Commutator Problems Check for loose or high commutator bars.

Possible Causes: •

Motor has been stalled

•

Motor has been too hot

Sheet 7: Brush and Motor Replacement, Diagrams BRUSH REPLACEMENT, DRIVE AND HYDRAULIC MOTORS Worn motor brushes must be replaced before they damage the surface of the commutator. Move the brush spring and remove a brush from the brush holder. Measure the length of the brush as shown in Figure 3-1. Replace all of the brushes if the length of one brush is less than the minimum length. Brushes are made to different specifications for motors used in different applications.

Use only replacement brushes approved by YALE MATERIALS HANDLING CORPORATION. 1.

Move key to OFF position. Disconnect the battery.

2.

Remove the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

3.

Remove the drive unit compartment cover to access the motors. Remove the brush covers to the motor. Wear eye protection. Use a vacuum cleaner or compressed air to remove dirt and "brush dust" from the commutator area.

4.

Make a note of the arrangement and connections of the brush assembly. The replacement brushes must be installed in the same positions as they were removed.

5.

Loosen the screw that fastens the brush wire to its terminal. Remove the brush springs and brushes.

6.

Inspect the brush holders for burns and damage. Make sure the brush holder is fastened tightly to the mounts at the end of the motor. Make sure the new brushes will move freely and smoothly in the brush holders.

7.

Connect the new brush wire to its terminal mount.

NOTE: When the brushes must be replaced, a recommendation is to also replace the brush springs.

8.

Check the brush springs for damage from heat and corrosion. Replace damaged brush springs. Check that the brush springs for approximately equal pressure. Brush springs normally have a spring pressure of approximately 1.0 to 2.0 Newtons per each cm 2 (1.5 to 3.0 lb. per each in 2 ) when measured with a spring scale.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 - Brush Assembly 1.

2.

3.

4.

5.

6.

BRUSH HOLDER (4) BRUSH YOKE BRUSH SPRING (4) BRUSH SET SPRING SURFACE OF BRUSH COMMUTATOR SURFACE OF BRUSH

A brush for a drive motor has an area of approximately 2.1 X 0.5 in = 1.05 in2 (5.33 X 1.27 cm = 6.8 cm2 ). Brush springs for the drive motor normally have a spring force of approximately 2 lbf and 8 ozf. 4 oz (10.2 1.1 Newtons) when measured with a spring scale as shown in Figure 3-3.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 - Brush Removal and Inspection 1.

2.

BRUSH BRUSH SPRING

A brush for a hydraulic pump motor has an area of approximately 1.74 X 0.375 in = 0.653 in 2 (4.42 X 0.95 cm = 4.21 cm 2 ). Brush springs for the hydraulic pump motor normally have a spring force of approximately 1 lb. and 8 oz. *4 ozf (6.3*1.1 Newtons) when measured with a spring scale as shown in Figure 3-3.

NOTE: The brush springs used in motors made by Yale have a constant force design. The force of the brush spring against the brush stays almost constant as the brush wears and becomes shorter in its brush holder.

9.

New brushes must be made to fit the surface of the commutator by an abrasive procedure called "stoning the commutator". Use a Brush Seater and Commutator Stone (No. 23-007M from the Ideal Company or an equivalent brush seater stone). Refer to STONING THE COMMUTATOR.

10. If new brushes are not fitted to the commutator by stoning, the contact surface can be small until the brushes wear to fit the commutator. This small surface can cause burns and a rough surface on the commutator. "Stoning the commutator" is most easily done when the motor rotates slowly. When the motor rotates at higher speeds, the centrifugal force removes the abrasive particles from the commutator more quickly. See Figure 3-6.

Drive Motor-Brush Replacement 1.

Move key to OFF position. Disconnect the battery.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-3 - Check Brush Spring Pressure 1.

2.

3.

4.

2.

SPRING SCALE BRUSH IN BRUSH HOLDER COMMUTATOR BRUSH SPRING

Remove the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

3.

Disconnect the spring and brush holder from the motor. Remove the brushes. Turn the steering handle for easier access to the brushes on the opposite side of the motor. Install new brushes.

4.

Install the brush holders and springs in the drive motor.

5.

Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

6.

Connect the battery, turn the key to the ON position and test operate the lift truck before returning the truck to service.

Hydraulic Pump Motor-Brush Replacement 1.

Move key to OFF position. Disconnect the battery.

2.

Remove the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

3.

It is necessary to loosen the two capscrews retaining the hydraulic unit to the frame and tip the hydraulic unit toward the front of the lift truck. Remove the two capscrews retaining the cover to the motor. Remove the cover.

Sheet 7: Brush and Motor Replacement, Diagrams 4.

Remove the springs and brushes. Inspect the brushes. The brushes should be a minimum of 7 mm (0.275 in) in length at the smallest point. Replace the brushes as a set. Inspect the springs for damage from heat (color changes) and corrosion.

Replace any damaged springs.

5.

Install the cover and the two capscrews to retain the cover.

6.

Tighten the two capscrews that retain the pump to the frame to 49 N*m (36 lb. ft) torque.

7.

Connect the battery, turn the key to the ON position and test operate the lift truck before returning the truck to service.

DRIVE MOTOR Removal

WARNING: Put blocks under each side of the truck under the drive unit frame. Position blocks on both sides of the load wheels. The blocks must prevent the lift truck from falling and causing injury or damage.

1.

Raise the drive wheel off the floor. Block the lift truck. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. Disconnect the battery.

2.

Remove the drive unit compartment cover to access the drive unit. Refer to Section 2-DRIVE UNIT COMPARTMENTREMOVAL AND INSTALLATION.

3.

Remove the control handle. Refer to Section 6 of this manual for the correct removal procedures for the type of motorized hand truck being worked on.

4.

Tag and disconnect the motor wires and the harness clamps on the motor.

5.

Remove the four capscrews that retain the motor to the drive unit housing.

6.

Lift the motor off of the drive unit housing.

7.

Remove the locknut, pinion gear and shims from the armature shaft.

8.

Inspect components for damage and replace as necessary. If the bevel gear is damaged, the bevel pinion must also be replaced. The pinion and gear can only be replaced as a matched set. Refer to Section 4-UPPER HOUSING-REMOVAL.

9.

Remove old sealant from the housing.

Installation 1.

Install shims, bevel gear and lock nut on the armature shaft. Tighten the nut to 53 N*m (39 lbf ft) torque.

2.

Apply sealing compound, Yale part number 5020589-05 or equivalent on the drive unit housing.

3.

Position the motor on the housing.

4.

Install the capscrews and lockwashers to attach the motor to the housing. Tighten the capscrews to 49 N*m (36 lbf ft) torque.

5.

Install the motor wires and harness clamps.

6.

Install the control handle. Refer to Section 6 of this manual for the correct installation procedures.

7.

Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

8.

Connect the battery. Lower the truck to the floor. Test operate the motorized hand truck before returning the truck to service.

Sheet 7: Brush and Motor Replacement, Diagrams HYDRAULIC PUMP MOTOR Removal 1.

Move key to OFF position. Disconnect the battery.

2.

Remove the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

3.

To remove the hydraulic pump motor the complete hydraulic unit must be removed. See Section 8-HYDRAULIC UNIT-REMOVAL.

4.

Remove the two capscrews retaining the motor to the hydraulic pump. Separate the motor from the pump.

5.

Remove the pinion end cover from the armature.

6.

Remove the screws that fasten the brush holder assembly to the commutator end cover.

7.

Disassemble the components of the motor as necessary to make repairs.

Installation 1.

Align the locating pin in the pump and install the hydraulic motor on the pump using the two capscrews to retain the pump and cover.

2.

Install the hydraulic unit to the frame. Refer to Section 8-HYDRAULIC UNIT-INSTALLATION.

3.

Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

4.

Connect the battery. Lower the truck to the floor. Test operate the motorized hand truck before returning the truck to service.

DRIVE AND HYDRAULIC MOTORS Disassembly 1.

Clean the outside surfaces of the motor before disassembly. Make index marks on the ends of the motor and the motor field ring so that the parts will be assembled again in the same positions.

2.

Remove the brush cover, if used. Remove the brushes and spring assemblies.

3.

Remove the capscrews from the commutator end of the motor. Carefully slide the end cover from the motor and armature shaft. Do not damage the parts. A puller is often necessary to separate the end cover from the motor field ring.

CAUTION: The pinion end cover and the armature are heavy components. Work carefully so that the field coils, pole pieces, and the armature are not damaged during disassembly and assembly.

4.

Remove the screws that fasten the pinion end cover to the motor field ring. Remove the end cover and armature. Use a plastic or rubber hammer as necessary to loosen the end cover.

5.

Remove the pinion end cover from the armature.

6.

Remove the screws that fasten the brush holder assembly to the commutator end cover.

7.

Disassemble the components of the motor as necessary to make repairs.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-4 - Typical Drive Motor 1. BRUSH HOLDER ASSEMBLY 2. CAPSCREW 3. TERMINAL SCREW 4. BRUSH SPRING SET 5. TERMINAL SCREW 6. COMMUTATOR END 7. BEARING 8. ARMATURE ASSEMBLY 9. BRUSH SET 10. CAPSCREW 11. FIELD COIL SET 12. CAPSCREW 13. POLE PIECE 14. INSULATOR 15. DRIVE END HEAD 16. BEARING 17. NUT 18. CAPSCREW 19. BEARING RETAINER 20. CAPSCREW 21. FIELD RING Assembly 1.

Make sure all of the components are clean. If the bearings were worn, install new bearings in the end covers.

2.

Make sure the field coils and pole pieces are installed correctly in the motor field ring.

3.

Install the brush holder assembly in the commutator end cover.

4.

Install the pinion end cover on the armature.

5.

Carefully install the armature and pinion end cover in the motor field ring. Make sure the index marks are aligned. Install and tighten the screws.

6.

Carefully install the commutator end cover on the armature and fasten it to the motor field ring. Install and tighten the capscrews.

7.

Install the brushes and spring assemblies. Replace the brush cover, if used. See HYDRAULIC PUMP MOTORBRUSH REPLACEMENT and DRIVE MOTOR-BRUSH REPLACEMENT.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-5 - Hydraulic Pump Motor 1. COVER BAND 2. COVER BAND END HEAD 3. WAVE WASHER 4. BEARING 5. BRUSH HOLDER 6. SPRING 7. BRUSH SET 8. FIELD COIL 9. TERMINAL KIT 10. CAPSCREW 11. MOUNTING BRACKET 12. ARMATURE 13. FAN 14. BEARING 15. END HEAD

COMMUTATOR REPAIRS

WARNING: Wear eye protection. Raise the drive wheel. Operate the motor at low speed. Protect your fingers, Do not use a brush seater stone less than 60 mm (2.5 in) in length.

1.

If the commutator has grooves or other damage, the armature must be removed so that the commutator can be repaired.

Motors are normally repaired by service personnel that have the special equipment required for the repair. Connect the battery so that the motor can be operated. The drive unit compartment cover must be removed for access to the motor. Raise the drive wheel. See Section 2-HOW TO PUT A LIFT TRUCK ON BLOCKS.

CAUTION: Do not permit the brush seater stone to stay in contact with the commutator too long and cause more

Sheet 7: Brush and Motor Replacement, Diagrams wear than necessary.

2.

Operate the motor so that the commutator rotates in the same direction as the long tips of the brushes. Apply the brush seater stone to the moving commutator with light pressure. Move the brush seater stone backward and forward across the surface of the commutator until the marks on the commutator are removed. Apply the brush seater stone to the commutator before each set of brushes so that the brush seater particles have an even distribution.

3.

Turn the key switch to the OFF position and disconnect the battery. Check all brush contact surfaces. The brushes fit correctly when 85% of the brush contact surface touches the commutator. This procedure normally requires approximately 15 to 45 minutes.

4.

When the brushes have the correct contact surface with the commutator, use compressed air to remove the abrasive dust from the commutator area and the motor.

5.

When the installation and checks are complete, install the brush cover. Make sure that the wires to the brushes do not touch any part of the motor case and cause a short-circuit.

Figure 3-6 - Stoning the Commutator NOTE: A brush seater stone can also be fastened to a wood stick with glue as shown in the illustration. This arrangement makes it easier to apply a brush seater stone in small places.

1.

BRUSH SEATER STONE

TESTS Damaged Field and Armature The tests described in the following paragraphs are to help a service person check a motor for damage and determine if it must be sent to a repair service for rebuilt motors. The resistance checks will not normally indicate a short-circuit in a motor winding. A resistance greater than 1 to 2 ohms can indicate a damaged winding. The motor must be removed from the lift truck and disassembled as shown in the illustrations before the tests can be done.

The armature windings in large electric motors normally have less than one ohm of resistance. The two commutator bars for a winding are found 180 degrees apart on the commutator. If a volt-ohmmeter (R*1 scale) is used to check the resistance between the two commutator bars of the winding, a resistance of more than one ohm indicates a problem in that winding. A resistance of infinity (*) indicates an open (damaged) winding.

If the armature has an open circuit, there will normally be two burned commutator bars on opposite sides of the commutator.

These burned areas will cause the brushes to wear rapidly. When the motor operates, large electric sparks and arcs occur as the damaged commutator bars rotate under each brush. See Figure 3-7.

Short-Circuit in an Armature Winding

Sheet 7: Brush and Motor Replacement, Diagrams A short-circuit in a motor winding is difficult to test because of the normal low resistance (less than one ohm) of a good armature. Use a Meggar to check for a short-circuit in a motor winding. A motor with a short-circuit in an armature winding will have a different sound when it begins to operate, but a service person must have experience to hear and understand the difference in sound. A winding with a short-circuit will also run hotter than a good winding and can have indications of heat damage. A winding that shows heat damage when the other windings are normal can have a short-circuit.

Another indication of a short-circuit will be a higher than normal current draw by the motor. A higher than normal current draw can also indicate other problems or needed adjustments and does not always indicate a short-circuit in a motor winding.

Short-Circuit in the Armature A volt-ohmmeter (R*10,000 scale) can be used to test for a short-circuit between an armature winding and the armature shaft.

Put one probe on the armature shaft and the other probe on a commutator bar. See Figure 3-7. A resistance of less than one megohm indicates a problem between a winding and the armature shaft.

NOTE: Clean the dirt and "brush dust" from the commutator area before making a test for a short-circuit.

Figure 3-7 - Test for an Armature Short-Circuit 1.

2.

3.

ARMATURE SHAFT COMMUTATOR PROBES TO OHMMETER

Open Circuit in a Field Coil The field windings in large electric motors normally have less than one ohm of resistance. If a volt-ohmmeter (R X 1 scale) is used to check the resistance between the two terminals of the winding, a resistance greater than one ohm indicates a problem in that winding or corrosion in the terminal connection. See Figure 3-8.

Short-Circuit in a Field Coil A short-circuit in a motor field winding is difficult to test because of the normal low resistance (less than one ohm) of a good field. A Meggar can be used to check for a short-circuit in a motor winding. A motor with a short-circuit in a field winding will have a different sound when it begins to operate, but a service person must have experience to hear and understand the difference in sound. A winding with a short-circuit will also run hotter than a good winding and can have indications of heat damage.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-8 - Test for an Open Field Circuit 1.

2.

FIELD COIL TERMINAL OHMMETER

Another indication of a short-circuit will be a higher than normal current draw by the motor. A higher than normal current draw can also indicate other problems or needed adjustments and does not always indicate a short-circuit in a motor winding.

Short-Circuit Between Field and Motor Case A volt-ohmmeter (R X 10,000 scale) can be used to test for a short-circuit between the field and the motor case. Put one probe on the motor case and the other probe on a field terminal. Check the resistance between the field terminal and the motor case. A resistance of less than one megohm indicates a problem between the field terminal and the motor case. Make sure that carbon dust has been cleaned from the motor before making this test.

Brush Holder Make sure the carbon dust has been removed from the brush holders. Use a volt-ohmmeter (R X 10,000 scale) to measure the resistance between the brush holder and the motor case. The correct resistance should be infinity (*).

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 Schematic 5045797-00 Type "E"-MPE-Up to S/N 575825 NOTES: 1.

USE WIRE #48C ON THIS MODEL (MPE). DO NOT USE WIRE #400 ON THIS TRUCK MODEL. TIE ALL UNUSED WIRES TO MAIN WIRE HARNESS

2.

FOR PROPER OPERATION OF B.D.I. WITH HOUR METER CONNECT WIRE #12A AS FOLLOWS:12 VOLT TRUCK CONNECT TO TERMINAL #1 AND 24 VOLT TRUCK CONNECT TO TERMINAL #5.

ALL DEVICES ARE SHOWN IN THE NORMAL POSITION WHEN THE UNIT IS STOPPED WITH NO OPERATOR. "REVERSE" IS TRAVEL IN THE DIRECTION OF THE FORKS.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 Schematic 5045797-00 Type "E"-MPE-Up to S/N 575825 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 Schematic 5046247-00 Type "E" -MPC-Up to S/N 575825

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 Schematic 5046247-00 Type "E" -MPC-Up to S/N 575825 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1-Schematic 5048747-00 Type "E"-MTR-From S/N 576843 ALL DEVICES ARE SHOWN IN THE NORMAL POSITION WHEN THE UNIT IS STOPPED WITH NO OPERATOR

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1-Schematic 5048747-00 Type "E"-MTR-From S/N 576843 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 Schematic 5048727-00-Type "E" -MPW-From S/N 575961 NOTE 1.

ON 12 VOLT TRUCK CONNECT WIRE #12A TO TERMINAL #1 AND ON 24 VOLT TRUCK CONNECT TO TERMINAL #5 ON BATTERY DISCHARGE INDICATOR WITH HOUR METER

ALL DEVICES ARE SHOWN IN THE NORMAL POSITION WHEN THE UNIT IS STOPPED WITH NO OPERATOR. "REVERSE" IS TRAVEL IN THE DIRECTION OF THE FORKS.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 Schematic 5048727-00-Type "E" -MPW-From S/N 575961 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 Schematic 5047437-00 Type "EE"-MPE NOTES: 1. USE WIRE #48C ON THIS MODEL (MPE). DO NOT USE WIRE #400 ON THIS TRUCK MODEL. TIE ALL UNUSED WIRES TO MAIN WIRE HARNESS. 2.

FOR PROPER OPERATION OF B.D.I. WITH HOUR METER CONNECT WIRE #12A AS FOLLOWS, 12 VOLT TRUCK CONNECT TO TERMINAL #1 AND 24 VOLT TRUCK CONNECT TO TERMINAL #5.

ALL DEVICES ARE SHOWN IN THE NORMAL POSITION WHEN THE UNIT IS STOPPED WITH NO OPERATOR. "REVERSE" IS TRAVEL IN THE DIRECTION OF THE FORKS.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 Schematic 5047437-00 Type "EE"-MPE (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 -Schematic 5048037-00-Type "EE"-MPC NOTE: 2. FOR PROPER OPERATION OF B.D.I. WITH HOUR METER CONNECT WIRE #12A AS FOLLOWS. 12 VOLT TRUCK CONNECT TO TERMINAL #1 AND 24 VOLT TRUCK CONNECT TO TERMINAL #5.

ALL DEVICES ARE SHOWN IN THE NORMAL POSITION WHEN THE UNIT IS STOPPED WITH NO OPERATOR. "REVERSE" IS TRAVEL IN THE DIRECTION OF THE FORKS.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-1 -Schematic 5048037-00-Type "EE"-MPC (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 Wiring Diagram 5045797-00-Type "E"-"MPE-Up to S/N 575825

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 Wiring Diagram 5045797-00-Type "E"-"MPE-Up to S/N 575825 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 Wiring Diagram 5048747-00 type "E"-MTR From S/N 576843

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 Wiring Diagram 5048747-00 type "E"-MTR From S/N 576843 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 -Wiring Diagram 5046247-00-Type "E" -MPC-Up to S/N 575825

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 -Wiring Diagram 5046247-00-Type "E" -MPC-Up to S/N 575825 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 - Wiring Diagram 5047437-00- Type "EE"- MPE

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 - Wiring Diagram 5047437-00- Type "EE"- MPE (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 -Wiring Diagram 5048037-00 -Type "EE" -MPC

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 -Wiring Diagram 5048037-00 -Type "EE" -MPC (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 Wiring Diagram 5048727-00 Type "E" -MPW- From S/N 575961

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-2 Wiring Diagram 5048727-00 Type "E" -MPW- From S/N 575961 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-3 -Options Diagram 5045797-00 -Type "E" -MPE- Up to S/N 575825

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-3 -Options Diagram 5048727-00 -Type "E" -MPW- From S/N 575961

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-3 Options Diagram 5048747-00 Type "E" MTR - From S/N 576843

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-3 - Options Diagram 5046247-00 Type "E" -MPC -Up to S/N 575825

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-3 Options Diagram 5047437-00 Type "EE" -MPE

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-3 - Options Diagram 5048037-00 Type "EE"- MPC

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-4 - Schematic 7524767-00 -Type "E" -MLW NOTE: 1.

ON 12 VOLT TRUCK CONNECT WIRE #12A TO TERMINAL #1 AND ON 24 VOLT TRUCK CONNECT TO TERMINAL #5 ON BATTERY DISCHARGE INDICATOR WITH HOUR METER

ALL DEVICES ARE SHOWN IN THE NORMAL POSITION WHEN THE UNIT IS STOPPED WITH NO OPERATOR. "REVERSE" IS TRAVEL IN THE DIRECTION OF THE FORKS.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-4 - Schematic 7524767-00 -Type "E" -MLW (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-4 Schematic 5048737-00 Type "E" -MPC From S/N 575826 NOTES: 2. FOR PROPER OPERATION OF B.D.I. WITH HOUR METER CONNECT WIRE #12A AS FOLLOWS. 12 VOLT TRUCK CONNECT TO TERMINAL #1 AND 24 VOLT TRUCK CONNECT TO TERMINAL #5.

ALL DEVICES ARE SHOWN IN THE NORMAL POSITION WHEN THE UNIT IS STOPPED WITH NO OPERATOR. "REVERSE" IS TRAVEL IN THE DIRECTION OF THE FORKS.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-4 Schematic 5048737-00 Type "E" -MPC From S/N 575826 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-4 Schematic 5048687-00 Type "E" MPE From S/N 575826 NOTES: 1.

USE WIRE #48C ON THIS MODEL (MPE). DO NOT USE WIRE #400 ON THIS TRUCK MODEL. TIE ALL UNUSED WIRES TO MAIN WIRE HARNESS.

FOR PROPER OPERATION OF B.D.I. WITH HOUR METER CONNECT WIRE #12A AS FOLLOWS. 12 VOLT TRUCK CONNECT TO TERMINAL

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-4 Schematic 5048687-00 Type "E" MPE From S/N 575826 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-4 Schematic 5047447-00 Type "EE" -MPW NOTE: 2. FOR PROPER OPERATION OF B.D.I. WITH HOUR METER CONNECT WIRE #12A AS FOLLOWS: 12 VOLT TRUCK CONNECT TO TERMINAL #1 AND 24 VOLT TRUCK CONNECT TO TERMINAL #5.

ALL DEVICES ARE SHOWN IN THE NORMAL POSITION WHEN THE UNIT IS STOPPED WITH NO OPERATOR. "REVERSE" IS TRAVEL IN THE DIRECTION OF THE FORKS.

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-4 Schematic 5047447-00 Type "EE" -MPW (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-4- Schematic 7524767-00-Type "E"-MLW(Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-5 Wiring Diagram 7524767-00 Type "E"- MLW

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-5 Wiring Diagram 7524767-00 Type "E" MLW (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-5 Wiring Diagram 5048737-00 Type "E" -MPC -From S/N 575826

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-5 Wiring Diagram 5048737-00 Type "E" -MPC -From S/N 575826 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-5 Wiring Diagram 5048687-00 Type "E" -MPE -From S/N 575826

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-5 Wiring Diagram 5048687-00 Type "E" -MPE -From S/N 575826 (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-5 Wiring Diagram 5047447-00 Type "EE" -MPW

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-5 Wiring Diagram 5047447-00 Type "EE" -MPW (Continued)

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-6-Options Diagram 75247667-00 Type "E"-MLW

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-6 Options Diagram 5048737-00 Type "E" -MPC- From S/N 575826

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-6 Options Diagram 5048687-00-Type "E" -MPE From S/N 575826

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-6 Options Diagram 5047447-00 Type "EE" -MPW

Sheet 7: Brush and Motor Replacement, Diagrams

Figure 3-6 - Options Diagram 5047447-00 - Type "EE"- MPW

Sheet 8: Drive Unit

DRIVE UNIT DRIVE UNIT-GENERAL The drive system consists of the drive motor assembly, the upper housing, the ring bearing assembly and the lower housing.

The same drive system is installed in all Yale motorized hand trucks.

The drive unit gear box is mounted on a large diameter ring bearing to provide for easy steering. All rotating parts of the drive unit are supported by either ball or roller bearings. Lubrication for the drive unit is provided by maintaining a specified level of gear oil in the lower housing. The ring bearing is lubricated using the grease fittings that are accessible through the openings provided in the drive unit compartment floor plate.

Drive Motor Assembly The drive motor is vertically mounted on top of the drive unit. In some instances it may be necessary to remove the drive motor to work on the drive unit, while in other cases the drive motor may remain attached to the drive unit while repairs are made. The complete drive unit, including the motor may also be removed, if necessary. Determine the extent of disassembly required before proceeding with any repairs. Refer to Section 3 of this manual for a general description, maintenance and repairs of the drive motor.

Upper Housing The upper housing of the drive unit supports the drive motor. A bevel pinion gear is attached to the drive motor shaft. The bevel pinion gear drives the bevel gear which is mounted on a shaft. The shaft is machined with spur gear teeth that drives the idler gear located in the lower housing. The brake drum is also mounted on the bevel gear shaft. The upper housing can be removed from the lower housing without removing the complete drive unit.

Lower Housing The lower housing contains the idler gear which meshes with the bevel gear shaft in the upper housing. The idler gear drives the 2nd reduction gear. The 2nd reduction gear is keyed to the drive wheel shaft. A cover on the side of the lower housing contains both a drain plug and a fill plug. The fill plug is located in the center of the cover and is also used to check the level of gear oil in the drive unit. A machined surface around the center of the lower housing provides the mounting surface for the drive unit bearing.

NOTE: The drive unit bearings used on these models no longer require any adjustment for wear or steering effort.

Figure 4-1 - Drive Unit

Sheet 8: Drive Unit 1.

2.

3.

4.

5.

6.

7.

DRIVE MOTOR UPPER HOUSING LOWER HOUSING BEARING GREASE FITTING FILL PLUG DRAIN PLUG

DRIVE WHEEL Removal

WARNING: Put blocks under each side of the truck under the drive unit frame. Position blocks on both sides of the load wheels. The blocks must prevent the motorized hand truck from falling and causing injury or damage.

1.

Raise the drive wheel off the floor. Block the motorized hand truck. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. Disconnect the battery.

2.

Loosen and remove the five wheel bolts and washers securing the clamp plate and drive wheel to the axle shaft . The clamp plate will be free from the wheel hub after the last wheel bolt is removed.

Remove the drive wheel.

Sheet 8: Drive Unit

Figure 4-2 - Drive Unit Assembly 1. DRIVE MOTOR 2. LOCKWASHER 3. CAPSCREW 4. BREATHER 5. SHIMS 6. BEVEL GEAR AND PINION SET 7. SHIMS 8. BALL BEARING 9. SHIM 10. RETAINER

Sheet 8: Drive Unit 11. CAPSCREW 12. BRAKE DRUM 13. WASHER 14. CASTLE NUT 15. COTTER PIN 16. ELASTIC STOP NUT 17. SOCKET HEAD CAPSCREW 18. CAPSCREW 19. CAPSCREW 20. LOCKWASHER 21. EXPANSION PLUG 22. BALL BEARING 23. SHAFT 24. KEY (5/16 X 1) 25. KEY (5/16 X 1 1/4) 26. O-RING 27. UPPER HOUSING 28. CAPSCREW 29. WASHER, HARDENED 30. BEARING CLAMP REAR 31. WELDMENT BEARING CLAMP-FRONT 32. BEARING SHIELD 33. CAPSCREW 34. SOCKET CAPSCREW 35. SPACER-BEARING 36. LUBE FITTING 37. BEARING-DRIVE UNIT 38. LOCKNUT 39. DOWEL PIN (1/4 X 7/8) 40. DOWEL PIN (1/4 X 5/8) 41. MAGNETIC PIPE PLUG 42. PIPE PLUG 43. COVER 44. IDLER SHAFT 45. O-RING 46. RETAINING RING 47. BALL BEARING 48. IDLER GEAR 49. SPACER 50. NUT 51. KEY 52. COTTER PIN 53. GEAR 54. RETAINING RING 55. BALL BEARING 56. ROLLER BEARING 57. OIL SEAL 58. DRIVE SHAFT 59. TIRE AND WHEEL ASSY. 60. CLAMP PLATE 61. HARDENED WASHER 62. WHEEL BOLT 63. LOWER HOUSING Installation 1.

Mount the drive wheel on the drive axle shaft.

2.

Align the clamp plate with the axle shaft.

3.

Install the washers and wheel bolts. Tighten the wheel bolts to 190-217 N*m (140-160 lbf ft) torque.

4.

Remove the blocks and lower the motorized hand truck to the floor. Connect the battery.

UPPER HOUSING

Sheet 8: Drive Unit Removal

WARNING: Put blocks under each side of the truck under the drive unit frame. Position blocks on both sides of the load wheels. The blocks must prevent the motorized hand truck from falling and causing injury or damage.

1.

Raise the drive wheel off the floor. Block the motorized hand truck. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. Disconnect the battery.

2.

Remove the drive unit compartment cover to access the drive unit. Refer to Section 2-DRIVE UNIT COMPARTMENTREMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

3.

Remove the control handle. Refer to Section 6-CONTROL HANDLE-REMOVAL for the correct removal procedures for the type of motorized hand truck being worked on.

4.

Tag and disconnect the motor wires and the harness clamps on the motor.

5.

Disassemble the brakes. Refer to Section 5 of this manual for the proper procedures.

6.

Remove the drive motor. Refer to Section 3-DRIVE MOTOR-REMOVAL.

7.

Remove the four capscrews retaining the upper housing to the lower housing.

8.

Straighten and remove the cotter pin retaining the castle nut on the brake drum. Remove the castle nut, brake drum and key.

9.

Remove the four capscrews and lockwashers securing the bearing retainer. Remove the bearing retainer and shims.

10. Use a drift pin to drive the bevel gear shaft out of the bearings. The expansion plug should come out of the housing. After the bevel gear shaft is loose, maneuver the bevel gear off of the shaft and out of the housing. Remove bearings, shims, O-ring, key and shaft.

11. Inspect components for damage and replace as necessary. Replace all O-rings, gaskets and cotter pins.

12. If either the bevel gear or pinion are damaged, they must be replaced as a matched set. Refer to BEVEL GEAR AND PINION ADJUSTMENT. Installation 1.

Apply a light coating of Vaseline or equivalent to a new O-ring and install the O-ring in the groove located on the bevel gear shaft. Install the bearing on the end of the bevel gear shaft. The bearing should be installed so that the shield on the bearing faces the centerline of the drive unit. Insert the key for the bevel gear in the shaft.

2.

Record the dimension etched on the back of the pinion. Refer to BEVEL GEAR AND PINION ADJUSTMENT. Position the bevel gear in the upper housing. Insert the shaft through the bearing bore. Align the keyway in the bevel gear with the key on the bevel gear shaft and continue installing the shaft until it protrudes through the other end of the housing.

3.

Tap the bearing previously installed on the bevel gear shaft into the housing. Make certain that the bevel gear is tight against the shaft shoulder.

4.

Install the shims that fit between the bevel gear and the bearing on the brake drum side of the shaft. Use enough shims to prevent any lateral movement of the bevel gear, but not too much to prevent the bearing retainer from fitting flush on the housing. The bevel gear should be tight against the bearing shield.

5.

Install the bearing retainer using the four capscrews and lockwashers. Tighten the capscrews to 36 lbf ft (49 N*m) torque.

6.

Insert the key into the keyway and install the brake drum on the shaft. Install the washer, nut and a new cotter pin. Tighten

Sheet 8: Drive Unit the castle nut to 136 N*m (100 lbf ft) torque before installing the cotter pin.

7.

Install the drive motor on the upper housing. Refer to Section 3-DRIVE MOTOR-INSTALLATION.

8.

Check for proper tooth contact between the bevel gear and pinion. Refer to BEVEL GEAR AND PINION ADJUSTMENT.

9.

Put a 3 mm (0.12 in) bead of silicone sealer around the outer edge of a new expansion plug and tap the plug into place in the housing bore.

10. Apply sealing compound, Yale part number 5020589-05 or equivalent, to the lower housing. Align the upper housing with the dowel pin in the lower housing and install the four capscrews and lockwashers. Tighten the three 1/2"-13 capscrews to 102-115 N*m (75-85 lbf ft) and the 3/8"-16 capscrew to 54-61 N*m (40-45 lbf ft) torque.

11. Assemble and adjust the brakes. Refer to Section 5 of this manual for the proper procedures.

12. Connect the motor wires and install the harness clamps.

13. Install the control handle. Refer to Section 6 of this manual for the correct installation procedures.

14. Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION. 15. Connect the battery. Lower the truck to the floor. Test operate the motorized hand truck before returning the truck to service.

LOWER HOUSING Disassembly The drive shaft, oil seal, bearings, and 2nd reduction gear can be serviced without removing the drive unit from the motorized hand truck.

WARNING: Put blocks under each side of the truck under the drive unit frame. Position blocks on both sides of the load wheels. The blocks must prevent the motorized hand truck from falling and causing injury or damage.

1.

Drain the gear oil from the drive unit into a suitable container. Raise the drive wheel off the floor. Block the motorized hand truck. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. Disconnect the battery.

2.

Remove the drive unit compartment cover to access the drive unit. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

3.

Remove the four capscrews and washers retaining the cover to the lower housing. Remove the cover.

4.

Loosen and remove the five wheel bolts, washers and clamp plate securing the drive wheel to the axle shaft. Remove the drive wheel.

5.

Remove the cotter pin and nut from the axle shaft. Use a brass bar to drive the shaft out of the 2nd reduction drive gear and bearings. Remove the gear and key.

WARNING: Be careful when removing or installing snap rings. These snap rings can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal and installation.

Sheet 8: Drive Unit 6.

Remove the snap ring and inner bearing.

7.

Remove the oil seal and outer bearing.

Assembly 1.

Before assembling the lower housing, wash and thoroughly clean all parts in a suitable solvent and dry. Make certain that all gasket material or sealing compound has been removed from the housings and covers, and that all mating surfaces are smooth.

2.

Check housing for cracks. Check housing bores for damage, especially around snap ring grooves. Check all threaded holes for damage. Check the drive unit breather.

3.

Check all bearings for excessive wear or flat spots. Dip clean bearings in new, clean gear oil and wrap in a clean, lint free cloth until ready for assembly.

4.

Check all gears and shafts for excessive wear, damaged teeth or keyways. Check keys for rounded edges or cracks. Check the keys for proper fit in the keyways of the shafts where they belong. If the keys do not fit properly, replace the key and/or shaft.

5.

Replace all worn or damaged parts. When assembling the drive unit use all new gaskets, O-rings and oil seals.

6.

Install the outer bearing and new oil seal in the lower housing bore. Apply a light coat of gear oil to the I.D. of the oil seal.

WARNING: Be careful when removing or installing snap rings. These snap rings can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal and installation.

7.

Install the inner bearing with the shield toward the reservoir side of the housing. Lock in place using a snap ring.

8.

Insert the key in the drive shaft, position the 2nd reduction gear in the housing and carefully insert the drive shaft through the oil seal, outer bearing, inner bearing and the 2nd reduction gear.

9.

Install the drive axle shaft nut on the shaft. Tighten the nut to 95-122 N*m (70-90 lbf ft) torque. Make certain that the hole in the shaft and nut are aligned and install a new cotter pin.

10. Apply sealing compound, Yale part number 5020589-05 or equivalent, to the cover surface of the housing. Align the cover on the lower housing. Install the four capscrews and lockwashers to retain the cover. Tighten the capscrews to 49 N*m (36 lbf ft) torque.

11. Mount the drive wheel on the axle shaft, install clamp plate, washers, and wheel bolts. Tighten the wheel bolts to 190-217 N*m (140-160 lbf ft) torque.

12. Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION. 13. Lower the truck to the floor. Connect the battery. Test operate the motorized hand truck before returning the truck to service.

DRIVE UNIT Removal

CAUTION: The steering bearing is attached to the frame floor plate and does not support the drive unit. Keep the drive unit supported at all times using a sling and an overhead hoist when removing the drive unit from the motorized hand truck.

Sheet 8: Drive Unit WARNING: Put blocks under each side of the truck under the drive unit frame. Position blocks on both sides of the load wheels. The blocks must prevent the motorized hand truck from falling and causing injury or damage.

1.

Drain the gear oil from the drive unit into a suitable container. Raise the drive wheel off the floor. Block the motorized hand truck. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. Disconnect the battery.

2.

Remove the drive unit compartment cover to access the drive unit. Refer to Section 2-DRIVE UNIT COMPARTMENTREMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

3.

Remove the control handle. Refer to Section 6 of this manual for the correct removal procedures for the type of motorized hand truck being worked on.

4.

Tag and disconnect the motor wires and the harness clamps on the motor.

5.

Disassemble the brakes. Refer to Section 5 of this manual for the proper procedures.

6.

If necessary, remove the drive motor. Refer to Section 3-DRIVE MOTOR-REMOVAL. Attach a sling and an overhead hoist to the drive unit.

7.

Loosen and remove the two capscrews and lockwashers retaining the rear bearing clamp. (The front clamping device is usually removed with the control handle.)

8.

Lower the drive unit to the floor, remove the sling and roll the unit out from under the truck. Move the unit to a clean work area.

9.

Remove the six capscrews and nuts. Disassemble the bearing shield, the bearing spacers and the bearing.

10. Disassemble the upper housing from the lower housing. Refer to UPPER HOUSING-REMOVAL. Remove the dowel pins that retain the idler shaft from the lower housing.

11. Install a 1/2"-20 capscrew or a slide hammer into the idler shaft to remove the shaft. Remove the idler shaft assembly.

WARNING: Be careful when removing or installing snap rings. These snap rings can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal and installation.

12. Disassemble the idler shaft by removing the spacer, snap rings, idler gear, bearing and O-ring. Discard the O-ring.

13. Remove the four capscrews and lockwashers retaining the cover to the lower housing. Remove the cover and gasket.

14. Loosen and remove the five wheel bolts, washers and clamp plate securing the drive wheel to the axle shaft. Remove the drive wheel.

15. Remove the cotter pin and nut from the axle shaft. Use a brass bar to drive the shaft out of the 2nd reduction drive gear and bearings. Remove the gear and key.

WARNING: Be careful when removing or installing snap rings. These snap rings can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal and installation.

16. Remove the snap ring and inner bearing.

Sheet 8: Drive Unit 17. Remove the oil seal and outer bearing.

Installation 1.

Before assembling the drive unit, wash and thoroughly clean all parts in a suitable solvent and dry. Make certain that all gasket material has been removed from the housings and covers, and that all mating surfaces are smooth.

2.

Check housings for cracks. Check housing bores for damage, especially around snap ring grooves. Check all threaded holes for damage. Check the drive unit breather.

3.

Check all bearings for excessive wear or flat spots. Dip clean bearings in new, clean gear oil and wrap in a clean, lint free cloth until ready for assembly.

4.

Check all gears and shafts for excessive wear, damaged teeth or keyways. Check keys for rounded edges or cracks. Check the keys for proper fit in the keyways of the shafts where they belong. If the keys do not fit properly, replace the key and/or shaft.

5.

Replace all worn or damaged parts. When assembling the drive unit use all new gaskets, O-rings and oil seals. Use the kit which contains all the normally replaceable items.

6.

Install the outer bearing and new oil seal in the lower housing bore. Apply a light coat of gear oil to the I.D. of the oil seal.

WARNING: Be careful when removing or installing snap rings. These snap rings can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal and installation.

7.

Install the inner bearing with the shield toward the reservoir side of the housing. Lock in place using a snap ring.

8.

Insert the key in the drive gear, position the drive gear in the housing and carefully insert the axle through the oil seal, outer bearing, inner bearing and the 2nd reduction gear.

9.

Install the drive axle shaft nut on the shaft. Tighten the nut to 95-122 N*m (70-90 lbf ft) torque. Make certain that the hole in the shaft and nut are aligned and install a new cotter pin.

10. Apply sealing compound, Yale part number 5020589-05 or equivalent to the cover surface of the housing. Align the cover on the lower housing. Install the four capscrews and lockwashers to retain the cover. Tighten the capscrews to 49 N*m (36 lbf ft) torque.

11. Mount the drive wheel on the axle shaft, install clamp plate, washers, and wheel bolts. Tighten the wheel bolts to 190-217 N*m (140-160 lbf ft) torque.

12. Apply a light coating of grease to the O-ring and install it on the idler gear shaft.

WARNING: Be careful when removing or installing snap rings. These snap rings can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal and installation.

13. Install the bearing in the idler gear and retain the bearing by installing the two snap rings in the gear.

14. Position the spacer and gear in the housing and install the shaft through the housing, gear and spacer. Tap the shaft into position. Use a screwdriver to turn the shaft to align the holes in the housing and shaft and install the two dowel pins to retain the shaft.

15. Install the upper housing. Refer to UPPER HOUSING-INSTALLATION. 16. Position the steering bearing, bearing spacers and bearing shield on the drive unit housing.

17. Move the drive unit into position under the motorized hand truck and install a sling. Attach the sling to an overhead hoist.

Raise the drive unit into alignment with the motorized hand truck frame. Attach the bearing to the frame using the six capscrews and nuts. Make certain that the socket head capscrews are installed in the countersunk holes of the motorized hand truck to provide steering clearance. Tighten all the capscrews to 76 N*m (56 lbf ft) torque.

Sheet 8: Drive Unit 18. Install the rear bearing clamp and retain using the two capscrews and lockwashers. Tighten the capscrews to 149-163 N*m (110-120 lbf ft) torque.

19. Install the drive motor. Section 3-Refer to DRIVE MOTOR-INSTALLATION. 20. Assemble and adjust the brakes. Refer to Section 5-BRAKE ADJUSTMENT. 21. Connect the motor wires and attach the harness clamps.

22. Install the control handle. Refer to Section 6 of this manual for the correct installation procedures.

23. Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION, .

24. Connect the battery. Lower the truck to the floor. Test operate the motorized hand truck before returning the truck to service.

BEVEL PINION AND GEAR ADJUSTMENT 1.

Record the dimension etched on the head of the old pinion. This dimension represents the distance from the face of the pinion to the center of the bevel pinion shaft.

2.

Compare the dimensions of the old and new pinions. Add or subtract the dimensions on the old pinion from that of the new pinion. Determine the thickness of shims that must be used.

EXAMPLE NO. 1 Old Dimension

43.129 mm (1.698 in)

New Dimension

43.002 mm (1.693 in)

Difference

0.127 mm (0.005 in)

NOTE: In this example the old shim pack plus an additional 0.005 in (0.127 mm) shim pack must be used.

EXAMPLE NO. 2 Old Dimension

43.129 mm (1.698 in)

New Dimension

43.256 mm (1.703 in)

Difference

0.127 mm (0.005 in)

NOTE: In this example the old shim pack less a 0.127 mm (0.005 in) shim must be used.

3.

Check that the proper number and the correct thickness of shims have been installed.

4.

Lightly apply gear marking compound on both sides to eight or nine of the bevel gear teeth.

5.

Rotate the bevel gear shaft in both directions at least one turn. This will squeeze the gear marking compound away from the areas of tooth contact. When making adjustments check both sides of the gear and pinion teeth. Remove or add shims at the motor and retainer as necessary to obtain the correct tooth contact. The correct tooth contact will also provide a proper backlash of 0.076-0.127 mm (0.003-0.005 in).

6.

Note the tooth contact patterns shown in Figure 4-3. Make the necessary adjustments to obtain the correct tooth contact pattern as listed: a.

If the contact pattern indicates a high narrow contact pattern, add a shim at the motor and add one at the retainer.

b.

If the contact pattern indicates a low narrow contact pattern, remove a shim at the motor and remove one at the retainer.

c.

If the contact pattern indicates a short heel contact pattern, add a shim at the motor and remove one at the retainer.

Sheet 8: Drive Unit d.

7.

If the contact pattern indicates a short toe contact pattern, remove a shim at the motor and add a shim at the retainer.

After the proper shims have been installed to obtain the correct tooth contact pattern, tighten the locknut on the armature shaft to 53 N*m (39 lbf ft) torque. Install the drive motor. Refer to Section 3-DRIVE MOTOR-INSTALLATION. Fill the drive unit with the recommended gear oil to the proper level. Refer to Section 2.

ADJUSTMENT OF CORRECT CONTACT PATTERN OF GEAR TEETH STEP 1. Apply gear marking compound to approximately 8 or 9 of the teeth of the bevel gear.

STEP 2. Check the tooth contact pattern on the bevel gear. Check the pattern on the side of the tooth where the pinion teeth apply the force.

STEP 3. Apply a small amount of resistance to the drive wheel and rotate the drive wheel using a wrench. Rotate the wheel so the pinion makes at least one revolution.

CORRECT TOOTH CONTACT PATTERN

WRONG CONTACT PATTERN HIGH NARROW CONTACT If the pattern shows the bevel pinion is too far from the center of the bevel gear, an adjustment in the direction of the arrows is necessary. Adjust the thickness of the shim sets as described in the assembly procedure.

LOW NARROW CONTACT If the pattern shows the bevel pinion is too far from the center of the bevel gear, an adjustment in the direction of the arrows is necessary. Adjust the shim sets at the spiral bevel gear as described in the assembly procedure.

SHORT HEEL CONTACT. If the pattern shows the bevel pinion is too close to the center of the bevel gear, an adjustment in the direction of the arrows is necessary. Adjust the shim sets at the spiral bevel gear as described in the assembly procedure.

SHORT TOE CONTACT If the pattern shows the bevel pinion is too close to the center of the bevel gear, an adjustment in the direction of the arrows is necessary. Adjust the thickness of the shim sets as described in the assembly procedure.

Sheet 8: Drive Unit

Figure 4-3 - Tooth Contact Pattern

Sheet 10: Control Handle

CONTROL HANDLE CONTROL HANDLE-GENERAL The control handle is designed to perform several functions. The handle is used to steer the truck on the MPW, MLW, MPE, MPC and MTR models and to apply the brakes on the MPW, MLW and MPE models. The handle also contains the direction controls, the lift controls and the brake on the MPC and MTR models. The drive unit assembly is turned as the control handle is pushed to the right or left to negotiate a turn. The drive unit is supported by a bearing that is mounted to the frame. This allows the lift truck to be maneuvered easily in any direction. The brakes are operated by linkage connected directly to the handle. The brakes are applied when the handle is in the full up or down position. The truck controls mounted in the handle are linked to the drive unit and hydraulic pump with a wiring harness that passes through the center of the handle. Presently there are three different types of handles being used on the motorized lift trucks.

The bottom mounted control handle assembly is used on the current MPW and MLW series of motorized lift trucks. The handle is designed to be used while the operator is walking with the lift truck. The speed /direction control, as well as the buttons for the horn, lift and lower operations are also found on the control handle. The control handle moves to the left or right to steer the lift truck.

The top mounted control handle assembly is used on the walk/ride lift trucks such as the MPE series of motorized lift trucks. This model is designed to be used while the operator is either walking with the truck or riding on a small platform to the left or right side of the control handle. The speed/direction control, as well as the buttons for the horn, lift and lower operations are also found on the control handle. The control handle moves to the left or right to steer the lift truck.

The third control handle assembly is used on the MPC and MTR models. The control handle on these models does not pivot and is positioned toward the riding platform where the operator stands. The control handle moves to the left or right to steer the lift truck. Brake levers are located on the control handle and are applied by hand pressure. The levers can be operated with either hand. The control handle has a three position tilt control to adjust the height of the handle. A parking brake lever is mounted at the base of the control handle column. The speed /direction control, as well as the buttons for the horn, lift and lower operations are also found on the control handle.

NOTE: The MPC and MTR models do not have an auto reverse feature.

Removal-MPW and MLW 1.

Remove the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

2.

Disconnect the battery. Disconnect the wiring harness plug located in the area of the drive motor. Tag and disconnect the wires to the brake switch.

3.

Remove the lower cover weldment after removing the two acorn nuts, and lockwashers located on the ends of the pivot shaft, and the capscrew and lockwasher located behind the drive motor. Install a regular 1/2"-20 hex. nut on each end of the pivot shaft to retain the pivot shaft supports.

4.

Remove the capscrews and flat washers retaining the left and right pivot shaft supports and control handle to the drive unit housing. The complete handle assembly can be removed from the lift truck.

5.

Unscrew the rubber bushing and washers. Remove the mounting block by removing the capscrew and flat washer retaining the block to the drive unit housing.

WARNING: The return springs used on the control handle has tension and can release with enough force to cause injury.

6.

Carefully remove the pivot shaft supports, springs, pivot shaft and brake cam.

Sheet 10: Control Handle 7.

Drive the pivot shaft bushings from the control handle.

Installation-MPW and MLW 1.

Install the bushings in the control handle. Align the brake cam and the control handle and install the pivot shaft. Position the springs on the shaft.

NOTE: The smaller of the two springs must be installed on the right side when facing the drive unit.

2.

Align the pivot shaft supports and springs and position the supports on the shaft. Temporarily install two 1/2"-20 hex. nuts on the shaft to retain the supports.

3.

Install the mounting block on the drive unit housing using the capscrew and flat washer. Install the washers and rubber bumper on the mounting block.

4.

Align the pivot shaft supports with the drive unit housing and install the two capscrews and flat washers. Tighten the capscrews to 49 N*m (36 lbf ft) torque.

Figure 6-1 - Control Handle Mounting-MPW and MLW 1. CAP NUT 2. LOCKWASHER 3. LOWER COVER WELDMENT 4. CAPSCREW 5. LOCKWASHER 6. PIVOT SHAFT SUPPORT 7. PIVOT SHAFT SUPPORT 8. CAPSCREW 9. HARDENED WASHER 10. PIVOT SHAFT 11. TORSION SPRING 12. TORSION SPRING

Sheet 10: Control Handle 13. STEER HANDLE WELDMENT 14. BUSHINGS 15. LUBE FITTING 16. WIRE HARNESS 17. BRAKE CAM 18. RUBBER BUMPER 19. FLAT WASHERS 20. MOUNTING BLOCK 21. CAPSCREW 22. FLAT WASHER 5.

Remove the two nuts that were temporarily installed on the pivot shaft. Align and install the lower cover weldment and install the two acorn nuts and lockwashers. Install the capscrew and lockwasher to retain the cover to the rear of the drive housing.

6.

Install the wires to the brake switch. Connect the wiring harness plug.

7.

Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

8.

Connect the battery and test operate the truck prior to returning the lift truck to service.

Removal-MPE 1.

Disconnect the battery. Remove the drive unit compartment cover to access the wiring and control handle mounting. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

2.

Disconnect the wiring harness plug located under the control handle steer disc (pivot). Tag and disconnect the wires to the brake switch. Remove the clamps retaining the control handle harness to the motor and control handle bracket. Be certain to note the routing of the wiring before disconnecting any wiring. The wiring must be routed properly at assembly to prevent steering problems and prevent chafing of the harness.

3.

Remove the two setscrews retaining the handle to the pivot pin. Note that the setscrews are positioned one behind the other in the same hole. Remove the pivot pin from the control handle pivot. Remove the control handle assembly from the control handle pivot. Remove the cam, spacers and the spring from the control handle assembly.

4.

Remove the cotter pin and clevis pin retaining the brake linkage to the bellcrank. Remove the three capscrews and lockwashers retaining the control handle pivot to the support weldment. Remove the control handle pivot.

5.

Disassemble the nut, lockwasher and screw retaining the bumper to the control handle pivot. Remove the bushings from the control handle pivot. Remove the two jam nuts, capscrew and adjusting bracket.

6.

Disassemble the four capscrews and lockwashers retaining the support weldment to the drive motor. Remove the two capscrews and lockwashers retaining the bracket to the drive unit housing and remove the support weldment.

Installation-MPE 1.

Align the support weldment with the tapped holes in the drive unit housing and install the capscrews and lockwashers.

Tighten the capscrews to 149-163 N*m (110-120 lbf ft) torque.

2.

Install the capscrews and lockwashers to retain the support weldment to the drive motor. Tighten the capscrews to 49 N*m (36 lbf ft) torque.

3.

Install the bushings in the control handle pivot. Install the bumper on the control handle pivot with the capscrew, lockwasher and nut. Align the control handle pivot on the support weldment and install the capscrews and lockwashers. Tighten the capscrews to 49 N*m (36 lbf ft) torque.

4.

Align the control handle assembly, spacers, spring, cam and the control handle pivot and install the pivot pin. Install the setscrews, one behind the other to retain the pivot pin.

5.

Align the brake linkage to the bellcrank and install the clevis pin. Install new cotter pin in the clevis pin.

6.

Install the clamps to retain the wiring harness. Connect the wires to the brake switch and connect the wiring harness plug.

Make certain that the wiring is properly routed to prevent steering problems and chafing of the harness.

Sheet 10: Control Handle 7.

Install the adjusting bracket on the control handle pivot. Check the brake spring adjustment before adjusting the tension of the control handle spring. Refer to Section 5-BRAKE ADJUSTMENT. To adjust the tension of the control handle spring by loosen the jam nuts and turn the capscrew. Turning capscrew in will apply more tension to the spring, causing the control handle to return to the upright position with more force. Loosening the capscrew will lessen the tension on the spring. After the spring tension has been adjusted to an acceptable level, lock the jam nuts. The maximum handle pull down effort is 5.4 kg (12 lbs).

Figure 6-2 - Control Handle Mounting-MPE 1. STEER HANDLE WELD. 2. BRAKE CAM 3. SETSCREW 4. SPACER 5. TORSION SPRING 6. CLAMP 7. FLAT WASHER 8. LOCKWASHER 9. SCREW, PAN HD. 10. PIN 11. BELLCRANK 12. SUPPORT WELDMENT 13. SCREW, BUTTON HD. 14. LOCKWASHER 15. ADJUSTER 16. CAPSCREW 17. LOCKNUT 18. CAPSCREW 19. COTTER PIN 20. SCREW, BUTTON HD. 21. RUBBER BUMPER 22. JAM NUT 23. PIVOT SHAFT 24. BUSHING 25. STEER DISC

Sheet 10: Control Handle 26. NUT 27. LOCKWASHER 28. LUBE FITTING 8.

Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

9.

Connect the battery and test operate the truck prior to returning the lift truck to service.

CONTROL HANDLE HEAD Removal The control handle head mechanical components can be removed and replaced when necessary. There are minor differences between models. Make certain to follow the instructions for the model of lift truck being worked on. See Figure 6-3, Figure 6-4, Figure 6-5, Figure 6-6 or Figure 6-7.

1.

Remove the drive unit compartment cover to access the wiring harness. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

WARNNG: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

2.

Disconnect the wiring harness plug located in the area of the drive motor.

3.

Remove the four screws and washers retaining the top cover to the base.

NOTE: The two center screws retain the travel switches to the base. Remove the top cover assembly and the auto reverse actuator, springs, and plunger.

4.

Remove the button head capscrews, washers and lockwashers from both ends of the handle. Remove the handle grips and the shaft.

5.

Remove the nuts and lockwashers retaining the plate on the eyebolts. Remove the plate.

6.

Disassemble the capscrews, flat washers, lockwashers and nuts that retain the two arms to the control handle.

Remember to retain the eyebolts when removing the capscrews so that they do not fall into the handle.

NOTE: To further disassemble the control handle refer to Section 3-STEERING HANDLE SWITCHES-REMOVAL. Installation NOTE: Make certain that the steering handle switches have been installed before installing the control handle head. Refer to Section 3-STEERING HANDLE SWITCHES-INSTALLATION. Make certain to follow the instructions for the model of lift truck being worked on. See Figure 6-3, Figure 6-4, Figure 6-5, Figure 6-6 or Figure 6-7.

1.

Align the bottom holes in both arms with the holes in the control handle and install the lower capscrew, flat washer, lockwasher and nut. Align the two eyebolts with the slots in the control handle and the two upper holes in the arms and install the capscrews, flat washers, lockwashers and capscrew. Tighten the capscrews to 31 N*m (20 lbf ft) torque.

2.

Install the plate, flat washers and nuts on the eyebolts. Tighten the nuts to 16 N*m (12 lbf ft) torque.

3.

Install the handle grips and align the shaft and grips with the holes in the arms and install the button head capscrews, flat washers and lockwashers. Tighten the button head capscrews to 31 N*m (23 lbf ft) torque.

4.

Align the top and bottom covers and position the plunger, spring, and traction reversing actuator between the covers. Install the four screws and washers.

5.

Connect the wiring harness plug.

Sheet 10: Control Handle 6.

Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

7.

Connect the battery and test operate the truck prior to returning the lift truck to service.

8.

Install the bushings in the control handle pivot. Install the adjusting bracket, capscrew and jam nuts on the bottom of the pivot and assemble the bumper to the pivot using the screw, lockwasher and nut. Attach the pivot to the control handle bracket using the three capscrews and lockwashers. Tighten the capscrews to 49 N*m (36 lbf ft) torque.

CONTROL HANDLE AND TOWER Removal-MPC and MTR NOTE: To disassemble the control handle tower refer to Section 5-BRAKE LINKAGE-DISASSEMBLY. 1.

Disconnect the battery. Remove the drive unit compartment cover to access the wiring harness. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

2.

Disconnect the wiring harness plug located in the area of the drive motor.

3.

Remove the two capscrews retaining the front cover to the tower and remove the cover.

4.

Remove the cotter pin and pin retaining the upper brake linkage to the bellcrank. The bellcrank is attached to the disc.

5.

Remove the four capscrews, lockwashers and nuts retaining the tower to the disc. The control head and the tower can be removed from the lift truck as a complete unit.

Installation-MPC and MTR 1.

Align the tower and control head to the holes located in the steer disc. Install the four capscrews, lockwashers and nuts.

2.

Align the upper brake rod and the bellcrank attached to the steer disc and install the pin. Install a new cotter pin.

3.

Align the front cover on the tower and install the two capscrews to retain the cover.

4.

Connect the wiring harness plug.

5.

Install the drive unit compartment cover.

6.

Connect the battery.

Sheet 10: Control Handle

Figure 6-3 - Control Handle Head-MPW and MLW 1. ACTUATOR 2. SPRING 3. RUBBER STOPPER 4. TOP COVER ASSEMBLY 5. ACTUATOR 6. ACTUATOR 7. ACTUATOR 8. SPRING 9. SWITCH RETAINER 10. SWITCH 11. SWITCH SUPPORT 12. CAPSCREW 13. LOCKWASHER 14. CAPSCREW 15. TOP COVER 16. CAPSCREW 17. CAPSCREW 18. FLAT WASHER 19. LOCKWASHER

Sheet 10: Control Handle 20. NUT 21. BUTTON HD. SCREW 22. LOCKWASHER 23. FLAT WASHER 24. ARM 25. PLATE 26. EYE BOLT 27. HANDLE GRIP 28. SHAFT 29. SWITCH ASSEMBLY 30. POTENTIOMETER 31. STANDOFF 32. INSULATOR 33. SWITCH 34. PLATE, SPACER 35. NUT PLATE 36. CAPSCREW 37. MOUNTING BRACKET 38. SETSCREW 39. SPUR GEAR 40. CAPSCREW 41. CONTROL LEVER 42. SETSCREW 43. ROLL PIN 44. SPUR GEAR 45. SHAFT 46. BUSHING 47. TORSION SPRING 48. CAM 49. ROLL PIN 50. CAPSCREW 51. LOCKWASHER 52. CAPSCREW 53. CAPSCREW 54. LOCKWASHER 55. BASE 56. STEER HANDLE WELDMENT 57. LOCKNUT 58. FLAT WASHER 59. HEATER BRACKET (OPT.) 60. RESISTOR ASSY (OPT.) 61. CAPSCREW (OPT.) 62. LOCKWASHER (OPT.) 63. NUT (OPT.)

Sheet 10: Control Handle

Figure 6-4 - Control Handle Head-MPE 1. ACTUATOR 2. SPRING 3. RUBBER STOPPER 4. TOP COVER ASSEMBLY 5. ACTUATOR 6. ACTUATOR 7. ACTUATOR 8. SPRING 9. SWITCH RETAINER 10. SWITCH 11. SWITCH SUPPORT 12. CAPSCREW 13. LOCKWASHER 14. CAPSCREW 15. TOP COVER

Sheet 10: Control Handle 16. CAPSCREW 17. CAPSCREW 18. FLAT WASHER 19. LOCKWASHER 20. NUT 21. CAPSCREW 22. LOCKWASHER 23. FLAT WASHER 24. ARM 25. PLATE 26. EYE BOLT 27. HANDLE GRIP 28. FLANGED BUSHING 29. SLEEVE WELDMENT 30. SHAFT 31. COTTER PIN 32. LINK ROD 33. SWITCH ASSEMBLY 34. POTENTIOMETER 35. STANDOFF 36. NUT PLATE 37. INSULATOR 38. SWITCH 39. PLATE, SPACER 40. SETSCREW 41. SPUR GEAR 42. CAPSCREW 43. MOUNTING BRACKET 44. CAPSCREW 45. CONTROL LEVER 46. SETSCREW 47. ROLL PIN 48. SPUR GEAR 49. SHAFT 50. BUSHING 51. TORSION SPRING 52. CAM 53. ROLL PIN 54. BASE 55. CAPSCREW 56. LOCKWASHER 57. CAPSCREW 58. LOCKWASHER 59. CAPSCREW 60. STEER HANDLE WELDMENT 61. LOCKNUT 62. FLAT WASHER 63. HEAT SHIELD (OPT.) 64. CAPSCREW (OPT.) 65. RESISTOR ASSY (OPT.) 66. LOCKWASHER (OPT.) 67. NUT (OPT.)

Sheet 10: Control Handle

Figure 6-5 - Control Handle Head-MPC 1. COVER-BLANK 2. FILLER 3. TOP COVER ASSEMBLY 4. LABEL 5. ACTUATOR 6. ACTUATOR 7. ACTUATOR 8. SPRING 9. SWITCH RETAINER 10. SWITCH 11. SWITCH SUPPORT 12. CAPSCREW 13. LOCKWASHER 14. CAPSCREW 15. TOP COVER 16. CAPSCREW 17. CAPSCREW 18. FLAT WASHER 19. LOCKWASHER 20. NUT 21. CAPSCREW 22. LOCKWASHER

Sheet 10: Control Handle 23. FLAT WASHER 24. ARM 25. PLATE 26. EYE BOLT 27. HANDLE GRIP 28. FLANGED BUSHING 29. SLEEVE WELDMENT 30. SHAFT 31. COTTER PIN 32. LINK ROD 33. SWITCH ASSEMBLY 34. POTENTIOMETER 35. STANDOFF 36. NUT PLATE 37. INSULATOR 38. SWITCH 39. PLATE, SPACER 40. SETSCREW 41. SPUR GEAR 42. CAPSCREW 43. MOUNTING BRACKET 44. CAPSCREW 45. CONTROL LEVER 46. SETSCREW 47. ROLL PIN 48. SPUR GEAR 49. SHAFT 50. BUSHING 51. TORSION SPRING 52. CAM 53. ROLL PIN 54. BASE 55. CAPSCREW 56. LOCKWASHER 57. CAPSCREW 58. LOCKWASHER 59. CAPSCREW 60. STEER HANDLE WELDMENT 61. LOCKNUT 62. FLAT WASHER 63. HEAT SHIELD (OPT.) 64. RESISTOR ASSY (OPT.) 65. CAPSCREW (1/2" LG.) (OPT.) 66. LOCKWASHER (OPT.) 67. NUT (OPT.)

Sheet 10: Control Handle

Figure 6-6 - Control Handle Head-MTR 1. COVER 2. FILLER 3. TOP COVER ASSEMBLY 4. LABEL 5. ACTUATOR-BLANK 6. ACTUATOR-HORN 7. ACTUATOR-BLANK 8. SPRING 9. SWITCH RETAINER 10. SWITCH 11. SWITCH SUPPORT 12. CAPSCREW 13. LOCKWASHER 14. CAPSCREW 15. TOP COVER 16. CAPSCREW 17. CAPSCREW 18. FLAT WASHER 19. LOCKWASHER 20. NUT

Sheet 10: Control Handle 21. CAPSCREW 22. LOCKWASHER 23. FLAT WASHER 24. ARM 25. PLATE 26. EYE BOLT 27. HANDLE GRIP 28. FLANGED BUSHING 29. SLEEVE WELDMENT 30. SHAFT 31. SWITCH ASSEMBLY 32. COTTER PIN 33. LINK ROD 34. BUSHING 35. SHAFT 36. CAM 37. ROLL PIN 38. CONTROL LEVER 39. ROLL PIN 40. SPUR GEAR 41. SHAFT 42. SET SCREW 43. SPUR GEAR 44. CAPSCREW 45. MOUNTING BRACKET 46. CAPSCREW 47. POTENTIOMETER 48. STANDOFF 49. NUT PLATE 50. INSULATOR 51. SWITCH 52. MOUNTING BRACKET 53. CAPSCREW 54. LOCKWASHER 55. CAPSCREW 56. LOCKWASHER 57. CAPSCREW 58. BASE 59. STEER HANDLE WELDMENT 60. FLAT WASHER 61. LOCKNUT

Sheet 10: Control Handle

Figure 6-7 - Control Handle Head-MLW 1. ACTUATOR 2. SPRING 3. RUBBER STOPPER 4. TOP COVER ASSEMBLY 5. COVER 6. ACTUATOR 7. COVER 8. SPRING 9. SWITCH RETAINER 10. SWITCH 11. SWITCH SUPPORT

Sheet 10: Control Handle 12. CAPSCREW 13. LOCKWASHER 14. CAPSCREW 15. TOP COVER 16. CAPSCREW 17. CAPSCREW 18. WASHER 19. LOCKWASHER 20. NUT 21. CAPSCREW 22. LOCKWASHER 23. WASHER 24. ARM 25. PLATE 26. EYE BOLT 27. HANDLE GRIP 28. SHAFT 29. SWITCH ASSEMBLY 30. TORSION SPRING 31. ROLL PIN 32. SPUR GEAR 33. ROLL PIN 34. SHAFT 35. CONTROL LEVER 36. BUSHING 37. CAM 38. STANDOFF 39. SPUR GEAR 40. SET SCREW 41. MOUNTING BRACKET 42. SET SCREW 43. CAPSCREW 44. NUT PLATE 45. INSULATOR 46. SWITCH 47. POTENTIOMETER 48. NUT PLATE 49. BASE 50. CAPSCREW 51. LOCKWASHER 52. CAPSCREW 53. LOCKWASHER 54. CAPSCREW 55. LOCKWASHER 56. NUT 57. STEER HANDLE WELDMENT 58. HEAT SHIELD (OPT.) 59. RESISTOR (OPT.) 60. CAPSCREW (OPT.) 61. LOCKWASHER (OPT.) 62. NUT (OPT.)

Sheet 11: Lift Linkage Load Wheel

LIFT LINKAGE AND LOAD WHEEL LIFT LINKAGE AND LOAD WHEELS-GENERAL On all motorized lift trucks except the MTR tractor and the MLW platform lift truck, when the lift button on the control handle is depressed the hydraulic pump sends high pressure hydraulic oil to the lift cylinder. This action extends the cylinder, operates the lift linkage and raises the forks. At the same time, the rocker arms and the rear links mounted under the drive unit platform are pulled upwards. This causes the pull rod assembly to be pulled toward the drive end of the truck. The movement of the pull rods in this direction causes the load wheels to pivot down on their pivot pins. The lift linkage is adjustable by removing an access plate and turning adjusting nuts located on the end of the pull rod. Proper adjustment is required to raise and lower the pallet forks evenly.

On the MLW platform lift truck, when the lift button on the control handle is depressed the hydraulic pump sends high pressure hydraulic oil to the lift cylinder. As pressure builds, the cylinder extends, forcing the load wheels downward. The downward motion of the load wheel pushes the link assemblies outward. This causes the platform to rise. At full cylinder extension, the height of the platform above the ground is 6 to 9 inches depending upon the link and the cylinder assembly mounted on the truck. The battery platform of this truck does not raise and lower with the platform.

LOAD WHEELS-MPW, MPE AND MPC Removal 1.

Use the lift button to raise the lift truck to its maximum height.

WARNING: Put blocks under both forks and on both sides of the drive tire. The blocks must prevent the lift truck from falling and causing injury or damage.

2.

Put blocks under both forks and on both sides of the drive tire. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS.

3.

Drive the roll pin retaining the axle shaft to the rear axle link out of the link and axle.

4.

Lower the lift cylinder using the lower button. This will raise the load wheels off the floor.

5.

Use a large screwdriver or drag link adjustment tool to remove the axle shaft. Remove spacers, oil seals, bearings and load wheel from the link. It may be necessary to use a brass or hardwood drift to drive the bearing races out of the wheel. Drive the bearing races out from the opposite sides.

6.

Remove all old lubricant. Clean and inspect all parts. Replace all defective parts.

Installation 1.

Prelubricate the bearings with the recommended grease, refer to Section 2. Install the bearings in the load wheel.

2.

Align the load wheel and bearings, oil seals, and spacers inside the link and insert the axle shaft. Tighten the axle shaft using a large screwdriver or drag link adjustment tool until tight and then back off on the shaft until the roll pin hole in the link aligns with the next slot in the shaft. The load wheel end play should be between 0.13-0.25 mm (0.005-0.010 in).

3.

Install the roll pin in the link and through the axle shaft.

4.

Raise the load wheels. Lubricate the load wheel. Refer to Section 2 this manual.

5.

Remove the blocks from under the forks and from each side of the drive tire. Lower the lift truck.

6.

Test operate the motorized hand truck before returning the truck to service.

Sheet 11: Lift Linkage Load Wheel

Figure 7-1 - Load Wheel Assembly-MPW, MPE and MPC 1.

2.

3.

4.

5.

6.

7.

8.

9.

SPACER OIL SEAL BEARING LOAD WHEEL LINK BUSHING LUBE FITTING (CORROSION ONLY) AXLE SHAFT ROLL PIN

REAR LINKAGE AND LOAD WHEEL ASSEMBLY- MPW, MPE AND MPC Removal 1.

Use the lift button to raise the lift truck to its maximum height.

WARNING: Put blocks under both forks and on both sides of the drive tire. The blocks must prevent the lift truck from falling and causing injury or damage.

2.

Put blocks under both forks and on both sides of the drive tire. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS.

3.

Raise the load wheels off the floor.

4.

Remove the four screws that retain the access cover to the fork. Remove the access cover.

5.

Remove the capscrew and nut retaining the pivot shaft to the yoke assembly. Remove the pivot shaft.

6.

Disassemble the capscrew and lockwasher retaining the pivot pin weldment to the load wheel assembly. Remove the pivot pin weldment and the pallet guide roller and spacer. The load wheel assembly is removed when the pivot pin weldment is removed.

7.

Disassemble the load wheel. See LOAD WHEEL-REMOVAL.

8.

Remove the bushings.

9.

Remove all old lubricant. Clean and inspect all parts for damage. Replace all defective parts.

Sheet 11: Lift Linkage Load Wheel

Figure 7-2 - Lift Linkage-MPW, MPE and MPC 1. LUBE FITTING 2. BUSHING 3. ROLL PIN 4. PIVOT PIN, UPPER LINK 5. UPPER LINK 6. ROLL PIN 7. PIVOT PIN, UPPER LINK 8. LUBE FITTING 9. LUBE FITTING 10. ROCKER ARM 11. BUSHING, UPPER LINK 12. BUSHING, ROCKER ARM 13. CAPSCREW 14. PIVOT PIN, DRIVE FRAME END 15. HEX. NUT 16. LOCKWASHER 17. CAPSCREW 18. PIN, WELDMENT 19. PIVOT PIN, PULL ROD 20. LOCKWASHER 21. CAPSCREW 22. BUSHING, PULL ROD 23. PULL ROD 24. JAM NUT 25. YOKE ASSEMBLY 26. BUSHING, PULL ROD 27. LUBE FITTING 28. PIVOT PIN WELDMENT 29. CAPSCREW 30. LOCKWASHER

Sheet 11: Lift Linkage Load Wheel 31. LOAD WHEEL ASSEMBLY 32. SPACER 33. ROLLER 34. HEX. NUT 35. PIVOT SHAFT, PULL ROD 36. SOCKET HEAD CAPSCREW Installation 1.

Press new bushings into the link. After the bushings are installed, line drill a 3.05 mm (0.12 in) diameter hole through each bushing, using the grease fitting hole as a guide. Install the grease fitting.

2.

Assemble the load wheel. Refer to LOAD WHEEL-INSTALLATION.

3.

Align and install the pallet guide roller, spacer and pivot pin weldment in the rear link. Install the capscrew and lockwasher.

4.

Adjust the pull rods, refer to PULL ROD ADJUSTMENT.

5.

Install the pivot pin through the rear link and yoke assembly and install the capscrew and nut to retain the pivot pin.

6.

Install the access cover on the fork using the four screws to retain the cover to the fork. Tighten the screws to 19 N*m (14 lbf ft) torque.

7.

Raise the load wheels off the floor. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. Lubricate the load wheel. Refer to Section 2.

8.

Remove the blocks from under the forks and from each side of the drive tire. Lower the lift truck.

9.

Test operate the motorized hand truck before returning the truck to service.

PULL ROD-MPW, MPE AND MPC Removal 1.

Use the lift button to raise the lift truck to its maximum height.

WARNING: Put blocks under both forks and on both sides of the drive tire. The blocks must prevent the lift truck from falling and causing injury or damage.

2.

Put blocks under both forks and on both sides of the drive tire. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS.

3.

Lower the lift cylinder using the lower button. This will raise the load wheels off the floor.

WARNING: Batteries are heavy and can cause an injury. Use care to avoid injury. Do NOT put hands, arms, feet and or legs between the battery and a solid object. Make sure the capacity of the lifting device and spreader bar is greater than the weight of the a battery. The weight of the battery is normally shown on the battery case. The maximum battery weight is shown on the lift truck nameplate. The spreader bar must NOT be made of metal or it must have insulated straps.

4.

Move the key to the OFF position. Disconnect the battery. Remove the battery. See Section 2-BATTERY-REMOVAL AND INSTALLATION.

5.

Remove the capscrew and lockwasher retaining the pivot pin weldment to the load wheel assembly. Remove the pivot pin weldment from the pull rod and the load wheel assembly.

6.

Remove the capscrew and lockwasher retaining the pull rod pivot pin through the opening in the battery compartment. Use a drift to drive the pivot pin out of the pull rod and rocker arm.

7.

Disassemble the pull rod from the yoke assembly by removing two jam nuts and the yoke assembly.

Sheet 11: Lift Linkage Load Wheel 8.

Remove the bushings from the yoke assembly and pull rod end.

9.

Remove all old lubricant. Clean and inspect all parts. Replace all defective parts.

Installation 1.

Install new bushings into the yoke assembly and the pull rod end. After the bushings are installed, line drill a 3.05 mm (0.12 in) diameter hole through each bushing, using the grease fitting hole as a guide. Install the grease fitting.

2.

Install the yoke assembly onto the pull rod. Install the jam nuts.

3.

Align and install the pivot pin in the pull rod and rocker arm. Install the capscrew and lockwasher to retain the pivot pin.

4.

Lubricate the grease fittings. Refer to Section 2.

5.

Install the battery in the battery compartment. See Section 2-BATTERY-REMOVAL AND INSTALLATION. Connect the battery.

6.

Remove the blocks from under the forks and from each side of the drive tire. Turn the key to the ON position and use the lower button to lower the lift truck to its minimum height. Adjust the pull rods so the lift truck lifts and lowers evenly. Refer to PULL ROD ADJUSTMENT.

7.

Test operate the motorized hand truck before returning the truck to service.

ROCKER ARM-MPW, MPE AND MPC Removal 1.

Use the lift button to raise the lift truck to its maximum height.

WARNING: Batteries are heavy and can cause an injury. Use care to avoid injury. Do NOT put hands, arms, feet and or legs between the battery and a solid object. Make sure the capacity of the lifting device and spreader bar is greater than the weight of the a battery. The weight of the battery is normally shown on the battery case. The maximum battery weight is shown on the lift truck nameplate. The spreader bar must NOT be made of metal or it must have insulated straps.

2.

Move the key to the OFF position. Disconnect the battery. Remove the battery. See Section 2-BATTERY-REMOVAL AND INSTALLATION.

WARNING: Put blocks under both forks and on both sides of the drive tire. The blocks must prevent the lift truck from falling and causing injury or damage.

3.

Put blocks under both forks and on both sides of the drive tire. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS.

4.

Remove the capscrew and lockwasher retaining the pivot pin weldment to the load wheel assembly. Remove the pivot pin weldment from the pull rod and the load wheel assembly.

5.

Remove the capscrew and nut retaining the drive frame end pivot pin to the rocker arm. Use a drift to drive the pivot pin out of the rocker arm and the drive frame.

6.

Disassemble the capscrew and lockwasher retaining the rocker arm pin weldment to the fork frame. Drive the pin weldment out of the frame using a drift pin.

7.

Remove the bushings from the rocker arm.

8.

Remove all old lubricant. Clean and inspect all parts. Replace all defective parts.

Installation

Sheet 11: Lift Linkage Load Wheel 1.

Install new bushings into the rocker arm. After the bushings are installed, line drill a 3.05 mm (0.12 in) diameter hole through each bushing, using the grease fitting hole as a guide. Install the grease fitting.

2.

Align the rocker arm with the fork frame and install the rocker arm pin weldment. Install the capscrew and lockwasher to retain the pin weldment.

3.

Align the rocker arm with the drive frame and install the drive frame pivot pin. Install the capscrew and nut to retain the drive frame pivot pin.

4.

Align the pull rod and the rocker arm and install the pivot pin weldment. Install the capscrew and lockwasher to retain the pivot pin.

5.

Lubricate the grease fittings. Refer to Section 2, this manual.

6.

Remove the blocks from under the forks and from each side of the drive tire.

7.

Install the battery in the battery compartment, see Section 2, this manual. Connect the battery.

8.

Turn the key to the ON position and use the lower button to lower the lift truck to its minimum height. Adjust the pull rods so the lift truck lifts and lowers evenly. Refer to PULL ROD ADJUSTMENT.

9.

Test operate the motorized hand truck before returning the truck to service.

UPPER LINK-MPW, MPE AND MPC Removal 1.

Disconnect the battery.

WARNING: Put blocks under both forks and on both sides of the drive tire. The blocks must prevent the lift truck from falling and causing injury or damage.

2.

Put blocks under both forks and on both sides of the drive tire. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS.

3.

Remove the drive unit compartment cover to access one end of the upper link.

4.

Use a drift pin to remove the roll pin retaining the pivot pin to the drive unit frame. Drive the pivot pin out of the frame and upper link.

5.

Use a drift pin to remove the roll pin retaining the pivot pin to the fork frame (at the rear of the battery box). Drive the pivot pin out of the fork frame and upper link.

6.

Remove the bushings from the upper link.

Installation 1.

Install new bushings into the upper link. After the bushings are installed, line drill a 3.05 mm (0.12 in) diameter hole through each bushing, using the grease fitting hole as a guide. Install the grease fitting.

2.

Align the pivot pin with the fork frame and upper link and install the pivot pin. Install a roll pin to retain the pivot pin.

3.

Align the pivot pin with the drive unit frame and the upper link and install the pivot pin. Install a roll pin to retain the pivot pin.

4.

Install the drive unit compartment cover.

5.

Remove the blocks from under the forks and from each side of the drive tire. Connect the battery.

6.

Test operate the motorized hand truck before returning the truck to service.

Sheet 11: Lift Linkage Load Wheel ADJUSTMENTS -MPW, MPE AND MPC Pull Rod The pull rods must be adjusted so that the machined surface on top of the rear link is flush to the frame when the lift truck is in the lowered position. If the rear link machined surface is not flush to the fork frame or if the load wheels are not carrying the load equally, an adjustment must be made. Make certain to check both forks and both load wheels.

1.

Position a flat bar across one of the forks. Use a tape rule or a ruler to measure the distance from the floor to the top of the fork. Record the dimension.

2.

Move the flat bar to the other fork and make the same measurement. Record the second measurement.

Figure 7-3 - Measuring Fork in Lowered Position 3.

Turn the key to the ON position and raise the fork to its maximum height.

4.

Place the flat bar across the first fork that was measured and take a measurement with the fork in the raised position. Record the dimension.

Figure 7-4 - Measuring Fork in Raised Position 5.

Move the flat bar to the other fork and take a measurement of the second fork.

6.

Compare the measurements taken. If the measurements taken are not within 4.6 mm (0.18 in) of each other or if the load wheels are not carrying the load equally an adjustment is required. The lowered fork height at the load wheel end should be 81.03 to 85.60 mm (3.19 to 3.37 in).

7.

Remove the four capscrews retaining the access covers on each fork.

CAUTION: Improper adjustment to the pull rods can cause excessive wear to one of the load wheels and poor

Sheet 11: Lift Linkage Load Wheel pallet entry and exit. When making any adjustments be certain that the measurements are the same on both forks. If an equal measurement cannot be obtained, the problem may be a twisted frame. A twisted frame must be replaced.

8.

There are two nuts on either side of the rear link and load wheel assembly. Loosen both outer jam nuts and make the necessary adjustment to the inner jam nuts. To lower the lift wheels, turn the inner nuts clockwise. This will shorten the working length of the pull rods. To raise the lift wheels, turn the inner nuts counterclockwise. The working length of the pull rod will be increased.

9.

After the adjustments have been made, tighten the jam nuts to 176 N*m (130 lbf ft) torque.

10. Install the covers and secure them using the four access cover capscrews.

11. Test operate the motorized lift truck before returning the truck to service.

Figure 7-5 - Adjusting Pull Rod Rear Forks NOTE: This adjustment is available only on lift trucks that have alligator forks. (Alligator forks are double pallet length forks.)

1.

Position a flat bar across one of the forks at the battery end. Use a tape rule or a ruler to measure the distance from the floor to the top of the fork. Record the dimension.

2.

Move the flat bar to the other fork and make the same measurement. Record the second measurement.

3.

Turn the key to the ON position and raise the fork to its maximum height.

4.

Place the flat bar across the first fork that was measured and take a measurement with the fork in the raised position. Record the dimension.

5.

Move the flat bar to the other fork and take a measurement of the second fork.

6.

Compare the measurements taken. If the measurements taken are not within 4.6 mm (0.18 in) of each other, an adjustment is required. The lowered fork height at the battery box end should be 82.80 to 88.90 mm (3.26 to 3.50 in).

7.

Loosen the nuts retaining the capscrews on both sides of the frame between the battery box and the drive unit frame. Adjust the capscrew to obtain the proper dimension when the forks are lowered. Tighten the nuts to retain the capscrews.

8.

Test operate the motorized lift truck before returning the truck to service.

CASTER WHEELS-MPE AND MPC Removal

Sheet 11: Lift Linkage Load Wheel WARNING: Put blocks under both forks and on both sides of the drive tire. The blocks must prevent the lift truck from falling and causing injury or damage.

1.

Raise the drive wheel off the floor. Block the lift truck. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. Disconnect the battery.

2.

Remove the four countersunk screws and nuts retaining the caster and spacer to the frame. Remove the caster wheel.

3.

Repeat the same procedure for the other caster, if necessary.

Installation 1.

Align the caster and spacer with the holes in the frame and install the four countersunk screws and nuts. Tighten the nuts to 115 N*m (85 lbf ft) torque.

2.

Repeat Step 1 to install the other caster, if necessary.

3.

Remove the blocks from under the lift truck and lower the truck to the floor. Test operate the truck prior to returning the truck to service.

Replacement NOTE: The caster wheel does not have to be removed from the lift truck frame to replace the wheel or the wheel axle. To replace the wheel or wheel axle follow the steps outlined.

WARNING: Put blocks under both forks and on both sides of the drive tire. The blocks must prevent the lift truck from falling and causing injury or damage.

1.

Raise the drive wheel off the floor. Block the lift truck. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS. Disconnect the battery.

2.

Remove the locknut retaining the wheel on the wheel axle. Drive the wheel axle out of the arms and remove the wheel.

3.

Align the wheel between both arms and install the wheel axle. Install the nut on the wheel axle. Tighten the nuts to 34-47 N*m (25-35 lbf ft) torque.

4.

Remove the blocks from under the lift truck and lower the truck to the floor. Test operate the truck prior to returning the truck to service.

Disassembly 1.

Remove the caster wheel from the frame. Refer to CASTER WHEELS-REMOVAL.

2.

Remove the locknut retaining the wheel on the wheel axle. Drive the wheel axle out of the arms and remove the wheel.

3.

Remove the locknut retaining the spacer between the arms. Remove the capscrew, washers and spacer.

4.

Remove the locknuts retaining the spacers and springs. Remove the spacers, springs and capscrews.

Sheet 11: Lift Linkage Load Wheel

Figure 7-6 - Caster Wheels 1. YOKE ASSEMBLY 2. BUSHING 3. PIN 4. PIN 5. CAPSCREW W/NUT 6. RETAINING RING 7. ARM 8. WHEEL AXLE W/NUT 9. WHEEL 10. SPACER 11. SPRING 12. CAPSCREW W/NUT 13. BUSHING 14. WASHER 15. SPACER 16. CAPSCREW 17. SPACER 18. NUT 5.

Remove one of the E-rings retaining the pin and bushings between the arms. Disassemble the pin, bushings and arms.

6.

Remove one of the E-rings retaining the pin and bushings to the yoke. Disassemble the pin and bushings from the yoke.

Assembly 1.

Align the bushings in the yoke and install the pin. Install the E-rings on the pin to retain the pin and bushings to the yoke.

2.

Align the arms, spacer and washers in the yoke and install the capscrew and locknut. Tighten the locknut to 0-4 N*m (0-3 lbf ft) torque.

3.

Align the spacer between the arms and install the E-rings on the pin to retain the bushings and pin to the arms.

4.

Align the holes in the pins and install the capscrews, springs, spacers and locknuts. The springs should be preloaded to 1.75 MPa (250 lbs). Install Caster Spring Adjustment Tool 5180968-99 over the caster spring. Tighten the nuts until the edge of the spring is even with the edge of the adjustment tool. The final spring length should range between 48.00 and 48.51 mm (1.890 and 1.910 in).

Sheet 11: Lift Linkage Load Wheel 5.

Align the wheel between the arms and install the wheel axle. Tighten the nuts to 34-47 N*m (25-35 lbf ft) torque.

6.

Remove the blocks from under the lift truck and lower the truck to the floor. Test operate the truck prior to returning the truck to service.

LOAD WHEELS-MTR AND MLW The load wheels used on these models are as listed in Table 7-1. The removal and installation for the different load wheels will be the same for all of these models.

Table 7-1 - Tire Size and Composition Removal

WARNING: Put blocks under both sides of the truck frame by the load wheels. Place blocks on both sides of the drive tire. The blocks must prevent the lift truck from falling and causing injury or damage.

1.

Put blocks under both sides of the frame near the load wheels. Place blocks on both sides of the drive tire. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS.

2.

Remove the three capscrews retaining the hub cap. Remove the hub cap.

3.

Straighten and remove the cotter pin retaining the castle nut on the axle. Remove the castle nut.

4.

Remove the load wheel, flat washers, dust collar, felt washer, bevel washer and bearings from the axle.

5.

Clean and inspect all parts. Remove all old lubricant. If the bearings are worn or damaged, remove the bearings from the wheel.

Installation 1.

Pack the bearings and load wheel cavity with grease. Refer to Section 2 for the recommended grease. Install the bearings in the load wheel.

2.

Install the beveled washer on the axle shaft. The beveled edge of the washer must face the axle shoulder. Install the dust collar and flat washer.

3.

Carefully install the load wheel on the axle shaft. Install the flat washer and castle nut. Tighten the castle nut while turning the load wheel by hand. The load wheel should turn freely. The wheel bearing end play should be 0.13-0.25 mm (0.005-0.010 in). If necessary, back off on the castle nut to align the castle nut with the hole in the axle shaft. Install a new cotter pin.

4.

Align the hub cap on the load wheel and install the capscrews to retain the hub cap.

5.

Remove the blocks from under the lift tractor and lower the tractor to the floor. Test operate the truck before returning the tractor to service.

Sheet 11: Lift Linkage Load Wheel LOAD WHEEL AXLE-MTR, MLW Removal

WARNING: Put blocks under both sides of the truck frame by the load wheels. Place blocks on both sides of the drive tire. The blocks must prevent the lift truck from falling and causing injury or damage.

1.

Put blocks under both sides of the frame near the load wheels. Place blocks on both sides of the drive tire. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS.

2.

Remove the load wheels. See LOAD WHEEL-REMOVAL.

3.

Disassemble the nut, lockwasher, flat washer and capscrew retaining the axle to the tractor frame. Remove the axle from the frame.

4.

Inspect and repair or replace the axle as required.

Figure 7-7 - Load Wheel and Axle-MTR and MLW 1. CAPSCREW 2. HUB CAP 3. CASTLE NUT 4. FLAT WASHER 5. ROLLER BEARING, OUTER 6. LOAD WHEEL 7. ROLLER BEARING, INNER 8. WASHER 9. DUST COLLAR 10. FELT WASHER 11. BEVELED WASHER 12. NUT 13. LOCKWASHER 14. FLAT WASHER 15. CAPSCREW 16. LOAD AXLE

Sheet 11: Lift Linkage Load Wheel 17. COTTER PIN Installation 1.

Install and align the axle with the mounting hole in the tractor frame. Install the capscrew, flat washer, lockwasher and nut to retain the axle to the tractor frame. Tighten the nut to 41 N*m (30 lbf ft).

2.

Install the load wheels. Refer to LOAD WHEEL-INSTALLATION. 3. Remove the blocks from under the lift tractor and lower the tractor to the floor. Test operate the truck before returning the tractor or lift truck to service.

3.

Remove the blocks from under the lift tractor and lower the tractor to the floor. Test operate the truck before returning the tractor or lift truck to service.

Figure 7-8 - Load Platform Lift Linkage-MLW 1.

2.

3.

LOAD PLATFORM HEX. NUT SPRING

Sheet 11: Lift Linkage Load Wheel 4. LINK ASSEMBLY 5. BUSHINGS 6. LUBE FITTING 7. COTTER PIN 8. PIVOT ROD 9. SETSCREW 10. ROLL PIN 11. SHAFT 12. FLAT WASHER 13. BUSHING 14. PIN-LIFT CYLINDER LOWER 15. COTTER PIN 16. SNAP RING 17. LIFT CYLINDER 18. PIN-LIFT CYLINDER UPPER 19. PIVOT ROD 20. ROLL PIN 21. SHAFT

LOAD PLATFORM LINKAGE-MLW Removal

WARNING: Put blocks under both sides of the truck frame by the load wheels. Place blocks on both sides of the drive tire. The blocks must prevent the lift truck from falling and causing injury or damage.

1.

Put blocks under both sides of the frame near the load wheels. Place blocks on both sides of the drive tire. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS.

2.

Disconnect the battery. Use a suitable lifting device to remove the battery from the lift truck.

3.

Remove the breather from the hydraulic unit and the breather from the drive unit. Install pipe plugs in the hydraulic unit and the drive unit. Use a suitable lifting device to raise the lift truck and lay the lift truck on its side. Support the lift truck while it is positioned on its side to keep the lift truck from falling.

4.

Measure and record the distance that the thread of the spring protrudes beyond the nut.

5.

Remove the nut. Unhook the spring from the frame of the lift truck.

6.

Remove the cotter pins retaining the pivot rod to the link assembly. Remove the setscrew retaining the pivot rod.

Remove the roll pin retaining the shaft to the link assembly. Use a drift pin to drive the shaft and pivot rod out of the link assembly. Remove the link assembly and flat washers between the frame and the link assembly.

7.

Repeat the procedure to remove the other link assembly. Remove the lift platform.

8.

Inspect the shafts, pivot rods, link assemblies and spring for damage. Replace any part found to be damaged. Inspect the bushings in the link assemblies. If damaged or worn, remove the bushings.

9.

If the lift cylinder must be removed, refer to Section 8-HYDRAULIC CYLINDER-REMOVAL.

Installation 1.

Install the bushings in the link assembly, if removed.

2.

Align the lift platform with the frame. Lubricate the shafts with oil or light grease. Align the link assembly with the load platform, align new flat washers and install the shaft. Use the slot in the end of the shaft and align the shaft with the hole in the load platform. Install the roll pin to retain the shaft to the load platform.

3.

Align the pivot pin in the opposite end of the link assembly and install the pivot pin in the link assembly and load platform.

Install new cotter pins at each end of the pivot pin. Install the setscrew to retain the pivot rod.

4.

Repeat the procedure for installing the other link assembly.

Sheet 11: Lift Linkage Load Wheel 5.

Hook the spring in the hole provided in the load platform. Install the nut. Tighten the nut to obtain the dimension previously recorded. (The length of thread of the spring that protrudes beyond the nut.)

6.

Use a suitable lifting device to return the lift truck to the normal operating position. Position blocks under the load wheels.

7.

Use a suitable lifting device and install the battery in the lift truck.

8.

Remove the plugs from the drive unit and the hydraulic unit. Check the oil level in both units. If necessary add the recommend oil to the proper level. Refer to Section 2. Install the breather in both the drive unit and the hydraulic unit.

9.

Remove the blocks from under the load wheels. Test operate the lift truck before returning the lift truck to service.

Sheet 12: Hydraulic System

HYDRAULIC SYSTEM HYDRAULIC SYSTEM-GENERAL The hydraulic system provides the force required to lift the loads on all walkie/rider lift trucks except the MTR. The hydraulic system on the motorized hand truck consists of the following individual components: •

Pump Motor Assembly

•

Hydraulic Pump Assembly

•

Solenoid Release Valve

•

Flow Control Valve

•

Pilot Relief Valve

•

Lift Cylinder

•

Hydraulic Tank

SYSTEM OPERATION Lifting a Load To lift, pull the lift control handle back. Moving this lever will turn on the pump motor. The electrical energy is converted into mechanical energy by the motor. This torque is transferred to the pump from the motor through the motor shaft and shaft coupling.

Hydraulic oil is pumped through the system as the pump begins to turn. A vacuum created inside of the pump draws oil out of the reservoir through the suction line. Air which is drawn into the reservoir through the breather displaces the pumped oil allowing it to be sent through the system. If the breather is clogged or blocked in any way the ability of the system to lift a load will be greatly reduced.

Oil which is pushed out of the pump passes first through a one-way check valve, then to the lift cylinder. The check valve prevents oil from flowing back to the pump when lifting ceases, keeping the lift cylinder in the raised position until lowered.

The piston will begin to lift the load when fluid pressure acting against it is high enough to overcome the weight of the load at rest on the forks/platform.

When the piston is fully extended to the end of its stroke or if the load is too heavy to be lifted by this particular truck, pressure will continue to build inside of the cylinder against the piston until the rated pressure needed to operate the relief valve is reached. When this occurs, the relief valve, which is normally closed, is forced back against its spring. This creates a path for the fluid to flow back to the reservoir.

Once relief valve pressure is reached, hydraulic oil will continue to be diverted from the lift cylinder to the reservoir until the lift button is released or electrical power is interrupted.

Lowering a Load A load is lowered by depressing the lower button. When the lower button is depressed electric current is sent to the normally closed solenoid lowering valve which causes it to change position and open a path for the trapped hydraulic oil to flow from the cylinder back to the reservoir.

The hydraulic pump and motor assemblies are mechanically joined together as a compact unit combining the reservoir, the pump, and the motor together as a single assembly. The pump is located inside of the hydraulic tank and coupled to the motor by an adapter plate, coupler drive and four capscrews.

Hydraulic unit servicing is best performed by removing the unit from the truck to a clean work area. Brush replacement for the motor can be easily performed with the pump installed on the truck. Refer to Section 3.

Sheet 12: Hydraulic System

Figure 8-1 - Hydraulic Schematic Hydraulic Lines 1.

All hydraulic lines must be thoroughly cleaned before installation.

2.

When making repairs use the least number of fittings and connections to minimize flow resistance and the possibility of leakage.

Hydraulic Oil The hydraulic oil in the system performs the dual function of the power transmission and lubrication. Using the correct fluid is essential to proper system operation. Refer to the Lubrication Charts for the recommended Hydraulic Oil to be used.

The level in the reservoir should be checked first when troubleshooting lifting problems. Low oil levels will make it appear that a problem exists with the battery or hydraulic system.

Cleanliness Adhere to the following precautionary steps to insure that the hydraulic system remains clean.

1.

Clean (flush) the entire system when a failure is encountered to make sure all paint, metal chips, welding shot and debris is removed.

2.

Filter each change of oil to prevent the introduction of contaminants into the system.

3.

Provide continuous protection from airborne contamination by keeping the breather clean and serviceable.

Sound Level Hydraulic system noise is caused by both improperly selected oil and loose or damaged system components.

•

Hydraulic oil with high or moderately high viscosities-At startup, temperatures can cause pump noises due to cavitation and also impedes the release of trapped air. Air does not have sufficient time to purge itself from the fluid while in the reservoir before recycling through the system.

•

Aerated Hydraulic Oil-Results in system noise that is similar to cavitation. Aerated oil is caused by the ingestion of air through the pipe joints of the inlet lines and high velocity discharge lines as well as cylinder rod packing. Aeration can also be caused by oil discharging above the fluid level.

HYDRAULIC UNIT Removal

Sheet 12: Hydraulic System

CAUTION: Make certain all the hydraulic cylinders are fully collapsed.

WARNING: Batteries are heavy and can cause an injury. Use care to avoid injury. Do NOT put hands, arms, feet and or legs between the battery and a solid object. Make sure the capacity of the crane and spreader bar is greater than the weight of the a battery. The weight of the battery is normally shown on the battery case. The maximum battery weight is shown on the lift truck nameplate The spreader bar must NOT be made of metal or it must have insulated straps.

1.

Move the key to the OFF position. Disconnect the battery. Use a spreader bar and lifting device to remove the battery. Do not let the battery move from side to side. Make sure the battery cables have clearance.

Figure 8-2 - Hydraulic System 1.

2.

3.

4.

5.

6.

7.

LIFT CYLINDER ASSEMBLY ELBOW ELBOW W/O-RING HYDRAULIC POWER UNIT HOSE ELBOW W/O-RING HOSE ASSEMBLY

WARNING: Put blocks under each side of the truck under the drive unit frame. Position blocks on both sides of the load wheels. The blocks must prevent the lift truck from falling and causing injury or damage.

2.

Raise the drive wheel off the floor and put blocks under both sides of the drive unit frame. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS.

3.

Remove the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

Sheet 12: Hydraulic System WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

4.

Discharge the capacitor in the transistor controller.

5.

Tag and disconnect all electrical wires to the hydraulic unit.

6.

Disassemble and plug the hydraulic lines to the hydraulic unit.

7.

Loosen and remove the two capscrews retaining the hydraulic unit to the frame. Support the hydraulic unit as the capscrews are being removed.

Figure 8-3 - Hydraulic Unit 1.

2.

3.

LIFT PUMP MOTOR CONTACTOR COUPLING

Sheet 12: Hydraulic System 4. ADAPTER 5. O-RING 6. RELIEF VALVE SEAT 7. RELIEF VALVE PLUNGER 8. RELIEF VALVE SPRING 9. GASKET 10. RELIEF VALVE CAP 11. O-RING 12. RELIEF VALVE ADJ. SCREW 13. RETAINER 14. CAPSCREW (SELF TAPPING) 15. O-RING 16. PUSH-ON RING 17. SHIM 18. RETURN TUBE 19. O-RING 20. PUSH-ON RING 21. WASHER 22. RETURN TUBE 23. O-RING 24. CAPSCREW (12 POINT) 25. BREATHER CAP 26. CAPSCREW (SELF TAPPING) 27. RESERVOIR 28. MAGNET 29. STRAINER 30. INLET TUBE 31. O-RING 32. O-RING RETAINER 33. LOCK RING RETAINER 34. CAPSCREW (SELF TAPPING) 35. HYDRAULIC PUMP 36. O-RING 37. O-RING 38. O-RING 39. SOLENOID RELEASE VALVE KIT 40. FLOW CONTROL VALVE 41. FLOW CONTROL VALVE SPRING 42. CHECK VALVE KIT 43. O-RING 44. DOWEL PIN 45. FILTER (24V ONLY) Installation 1.

Align the hydraulic unit with the mounting holes in the frame and install the two capscrews. Tighten the hydraulic unit mounting capscrews to 36 lbf ft (49 N*m) torque.

2.

Install the hydraulic lines to the hydraulic unit.

3.

Connect all the electrical wires to the hydraulic unit.

4.

Remove the blocks and lower the lift truck to the floor.

5.

Remove the breather and add the recommended hydraulic oil until the oil is visible in the fitting for the breather/fill plug.

Replace the breather. If too much hydraulic oil is added, the oil will leak from the breather during operation.

6.

Install the battery. See Section 2-BATTERY-REMOVAL AND INSTALLATION. Connect the battery. Operate the lift truck until the hydraulic oil reaches operating temperature.

Remove the breather and check the hydraulic oil level. If necessary add additional oil. Check for hydraulic oil leaks.

7.

Install the drive unit compartment cover. Test operate the lift truck prior to returning the truck to service.

HYDRAULIC PUMP

Sheet 12: Hydraulic System Removal 1.

Remove the hydraulic unit from the lift truck. Refer to HYDRAULIC UNIT-REMOVAL.

2.

Clean the reservoir and pump area to prevent contaminants from entering the hydraulic system.

3.

Remove the four capscrews retaining the reservoir to the hydraulic unit. Tap around the perimeter to break the seal and separate the reservoir from the motor assembly.

4.

Remove the spring retaining screw from the suction tube.

5.

Remove the suction tube and strainer by pulling down and out.

6.

Remove the four capscrews retaining the pump to the drive motor.

7.

Disassemble the pump assembly and coupling from the adapter.

Installation NOTE: When servicing the hydraulic pump always replace all seals and O-ring. Clean or replace the strainer as required.

1.

Clean and lubricate all components using clean hydraulic oil.

2.

Replace all O-rings and seals.

3.

With the motor resting with the adapter plate up, grease the coupler and coupler cavity. Align the pump mounting holes with the holes in the motor. Insure that the tang is seated into the motor.

4.

Install the four capscrews and tighten to 10 to 12 lbf ft (13.6 to 16.3 N*m) torque.

5.

Install the O-rings into the pump cavities. Apply grease to the return tubes. Insert tubes into pump cavities and O-rings.

Grease the suction tube and insert into locking device with hole. Install and tighten the spring retaining screw to secure the suction tube.

6.

Make certain the magnet is clean. Install the magnet into the reservoir.

7.

Remove the retainer and replace the O-ring. Lightly grease the O-ring before installation.

8.

Align the reservoir so the hose connections will be in the same position as they were prior to removal. Install the four capscrews to retain the reservoir.

9.

Install the hydraulic unit. Refer to HYDRAULIC UNIT-INSTALLATION.

10. Remove the breather and fill the reservoir with the recommended oil. Refer to Section 2 this manual. Add oil until the oil is visible in the tee fitting for the breather. If too much oil is added, the oil will leak from the breather during operation.

If too much oil has been added, drain the excess or use a suction device to remove some of the oil.

11. Jog the pump motor three or four times to insure that the pump draws oil and the pump components are lubricated.

Operate the forks up and down three or four times to remove air from the system. Operate the lift truck until the hydraulic oil reaches operating temperature. Remove the breather and check the hydraulic oil level. If necessary add additional oil. Check for hydraulic oil leaks.

12. Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION. Test operate the motorized hand truck before returning the truck to service.

HYDRAULIC PUMP RESERVOIR Removal The reservoir of the hydraulic pump unit can be removed without removing the complete hydraulic unit.

CAUTION: Make certain the hydraulic cylinder is fully collapsed.

Sheet 12: Hydraulic System 1.

Move the key to the OFF position. Disconnect the battery.

2.

Remove the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION.

WARNING: The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and injury, discharge the capacitor before inspecting or repairing any component in the drive unit compartment. Wear safety glasses. Make certain the battery has been disconnected. Use a screwdriver or jumper wire to make a short-circuit across the B+ and B- terminals of the transistor controller.

3.

Discharge the capacitor in the transistor controller.

4.

Disassemble and plug the hydraulic lines to the hydraulic unit.

NOTE: The reservoir must be lowered below the suction tube before attempting to move the reservoir away from the lift truck.

Remember the reservoir may contain hydraulic oil. Dispose all used oil in accordance with local regulations.

5.

Remove the four capscrews retaining the reservoir to the hydraulic unit. Carefully remove the reservoir.

6.

Clean the reservoir, the magnet and the suction screen. Inspect the screen for damage and replace if necessary.

Installation 1.

Lubricate a new O-ring using clean hydraulic oil and install into the pump body.

2.

Align the reservoir in the proper position and install the four capscrews to retain the reservoir to the hydraulic unit.

3.

Install the hydraulic lines to the hydraulic unit.

4.

Remove the blocks and lower the lift truck to the floor.

5.

Remove the breather and add the recommended hydraulic oil until the oil is visible in the fitting for the breather/fill plug.

Replace the breather. If too much hydraulic oil is added, the oil will leak from the breather during operation. If too much oil has been added, drain the excess or use a suction device to remove some of the oil.

6.

Connect the battery. Jog the pump motor three or four times to insure that the pump draws oil and the pump components are lubricated. Operate the forks up and down three or four times to remove air from the system. Operate the lift truck until the hydraulic oil reaches operating temperature. Remove the breather and check the hydraulic oil level.

If necessary add additional oil. Check for hydraulic oil leaks.

7.

Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION. Test operate the lift truck prior to returning the truck to service.

HYDRAULIC CYLINDER Repacking 1.

Raise the motorized lift truck forks/platform to one half its maximum height.

2.

Place blocks under the forks. Block the drive wheel. Refer to Section 1, this manual for the recommended blocking procedure.

3.

Remove the drive unit compartment cover. Refer to Section 2, this manual.

4.

Relieve pressure from the hydraulic cylinder.

5.

Drive the roll pin retaining the top clevis pin out of the frame and clevis pin. Remove the top clevis pin.

6.

Manually collapse the piston into the cylinder while depressing the lower switch.

7.

Move the cylinder toward the rear of the truck. Loosen the gland nut. Extract the piston, gland nut and rod from the cylinder.

Sheet 12: Hydraulic System 8.

Disassemble the nut and piston from the cylinder rod. Remove the spacers, if used, and slide the rod out of the gland nut.

9.

Replace all seals, packing and O-rings.

CAUTION: Lubricate the seals, packing and O-rings with clean hydraulic oil before assembling. Make certain to install spacers, if any were removed.

10. Install the seals, packing and O-rings as necessary into the gland and piston after coating them with clean hydraulic oil.

11. Carefully install the rod through the gland nut. Install the piston, spacer (if necessary), and the locknut. Tighten the locknut (lubricated) to 110 lbf ft (150 N*m) torque.

CAUTION: Make certain that none of the sealant gets into the cylinder. Allowing sealant to get into the hydraulic system may cause damage to the components within the hydraulic system.

12. Carefully install the rod assembly into the cylinder. Apply sealant 5017029-02 or equivalent to the threads of the gland nut.

Tighten the gland nut to 20 lbf ft (27 N*m) torque.

13. Align and install the top clevis pin into the frame and cylinder rod. Install the roll pin to retain the clevis pin in the frame.

14. Remove the blocks and lower the lift truck to the floor.

15. Remove the breather and add the recommended hydraulic oil until the oil is visible in the fitting for the breather/fill plug.

Replace the breather. If too much hydraulic oil is added, the oil will leak from the breather during operation. If too much oil has been added, drain the excess or use a suction device to remove some of the oil.

16. Jog the pump motor three or four times to insure that the pump draws oil and the pump components are lubricated.

Operate the forks up and down three or four times to remove air from the system. Operate the lift truck until the hydraulic oil reaches operating temperature. Remove the breather and check the hydraulic oil level. If necessary add additional oil. Check for hydraulic oil leaks.

17. Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION. Test operate the lift truck prior to returning the truck to service.

Sheet 12: Hydraulic System

Figure 8-4 - Hydraulic Cylinder 1.

2.

3.

4.

5.

6.

7.

8.

LOCKNUT PISTON CYLINDER TUBE PISTON ROD PISTON HEAD BUSHING SEAL ROD

Removal 1.

Raise the motorized lift truck forks/platform to one half of its maximum height.

WARNING: Put blocks under each fork. Position blocks on both sides of the drive wheel. The blocks must prevent the lift truck from falling and causing injury or damage.

2.

Place blocks under the forks. Block the drive wheel. See Section 1-HOW TO PUT A LIFT TRUCK ON BLOCKS.

3.

Remove the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

4.

Relieve pressure from the hydraulic cylinder.

5.

Drive the roll pin retaining the top clevis pin out of the frame and clevis pin. Remove the top clevis pin.

WARNING: Be careful when removing or installing snap rings. These snap rings can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection

Sheet 12: Hydraulic System during removal and installation.

6.

Disassemble the snap ring retaining the bottom clevis pin. Remove the bottom clevis pin and the hydraulic cylinder.

Installation 1.

Align the bottom of the cylinder with the frame and install the bottom clevis pin.

WARNING: Be careful when removing or installing snap rings. These snap rings can come loose during removal or installation with enough force to cause an injury. Always use the correct snap ring pliers and wear eye and face protection during removal and installation.

2.

Install the snap ring to retain the clevis pin.

3.

Align the top of the cylinder rod with the frame and install the top clevis pin. Install the roll pin to retain the clevis pin.

4.

Remove the blocks and lower the lift truck to the floor.

5.

Remove the breather and add the recommended hydraulic oil until the oil is visible in the fitting for the breather/fill plug.

Replace the breather. If too much hydraulic oil is added, the oil will leak from the breather during operation. If too much oil has been added, drain the excess or use a suction device to remove some of the oil.

6.

Jog the pump motor three or four times. Operate the forks up and down three or four times to remove air from the system.

Operate the lift truck until the hydraulic oil reaches operating temperature. Remove the breather and check the hydraulic oil level. If necessary add additional oil. Check for hydraulic oil leaks.

7.

Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION. Test operate the lift truck prior to returning the truck to service.

RELIEF VALVE ADJUSTMENT

WARNING: Do not make repairs or adjustments unless you have both authorization and training. Repairs and adjustments that are not correct can make a dangerous operating condition. Do not operate a lift truck that needs repairs. Report the need for repairs to your supervisor immediately. If repair is necessary, put a "DO NOT OPERATE" tag on the control handle. Remove the key from the key switch.

1.

Remove the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT-REMOVAL AND INSTALLATION.

2.

Clean any build up of dirt from around the hydraulic unit.

3.

Relieve pressure from the hydraulic cylinder.

4.

Disassemble the supply line from the pump and install a tee. Install the supply line and a pressure gauge of the proper capacity or Yale Special Tool 5180968-12 Quadrigauge with an adapter.

5.

The relief valve adjustment screw is covered with a silicone sealant to prevent unauthorized adjustments. Remove the sealant. Adjust the relief valve by turning the adjusting screw until the proper setting is obtained on the gauge. The relief pressure should be taken with the pump running and the forks or platform fully raised. It may be necessary to stop the pump, make a minor adjustment and take the pressure reading again. The pressure readings should be:

Sheet 12: Hydraulic System 6.

Remove the pressure gauge and tee from the supply line. Apply a small amount of sealant over the adjustment screw.

7.

Remove the breather and add the recommended hydraulic oil until the oil is visible in the fitting for the breather/fill plug.

Replace the breather. If too much hydraulic oil is added, the oil will leak from the breather during operation. If too much oil has been added, drain the excess or use a suction device to remove some of the oil.

8.

Jog the pump motor three or four times. Operate the forks up and down three or four times to remove air from the system.

Operate the lift truck until the hydraulic oil reaches operating temperature. Remove the breather and check the hydraulic oil level. If necessary add additional oil. Check for hydraulic oil leaks.

9.

Install the drive unit compartment cover. Refer to Section 2-DRIVE UNIT COMPARTMENT COVER-REMOVAL AND INSTALLATION. Test operate the lift truck prior to returning the truck to service.

TROUBLESHOOTING-LIFT ASSEMBLIES

TROUBLE SHOOTING-HYDRAULIC CYLINDERS

TROUBLESHOOTING-HYDRAULIC PUMP

Sheet 12: Hydraulic System

Sheet 13: Battery Charging System

BATTERY AND CHARGING SYSTEM BATTERY AND CHARGING SYSTEM-GENERAL This section describes selection and maintenance of large batteries used in electric lift trucks. This information pertains to the service personnel that maintain industrial truck batteries.

SAFETY TIPS FOR HANDLING INDUSTRIAL TRUCK BATTERIES

1.

WARNING: Disconnect the battery from the lift truck when doing maintenance and repair work.

Why-The live current may cause arcing or a short circuit with attendant damage to equipment or injury.

2.

WARNING: Wear rubber apron, gloves, boots and goggles, when handling, checking, filling, charging or repairing batteries.

Why-To protect yourself against burns resulting from accidental spillage of electrolyte - a mixture of sulfuric acid and water.

3.

WARNING: Keep open flames away from batteries - do not check electrolyte level with a cigarette lighter or match. USE A FLASHLIGHT OR PERMANENT LIGHT. Do not smoke or create sparks.

Why-The space between the underside of the cover and the top of the electrolyte in the cell usually contains a hydrogen oxygen mixture which is explosive when ignited.

4.

WARNING: Be sure water is readily available in case electrolyte accidentally splashes on your skin or clothing. Extreme care should be taken in flushing electrolyte from the eye. Use plain water only and obtain medical attention immediately.

Why-Volumes of water applied quickly and continuously will prevent serious injury to the skin. Quick medical attention is necessary to assure proper care and treatment.

5.

WARNING: Apply strong neutralizer such as baking soda when acid is spilled on the floor and clean up promptly.

Why-Baking soda will neutralize the acid and make it safe to clean or flush from the floor.

6.

WARNING: Take proper care in melting the sealing compound when preparing to seal a battery. Avoid puncturing the hard surface of partially melted compound with a screwdriver or other sharp tool. Compound may ignite if it is heated too rapidly.

Why-The hot liquid may squirt up and burn your hand, face or body. If it should catch fire it creates the hazard of an open flame. Burning consumes oil in the compound and impairs its useful characteristics.

Sheet 13: Battery Charging System

Figure 9-1 - Lead-Acid Industrial Truck Battery 7.

Remove vent caps from nearby cells when preparing to assemble a repaired cell into the battery. Cover the vent holes with layers of damp cloth before using lead burning equipment on the intercell connectors in order to integrate the cell into the battery circuit. Also, use dark glasses to protect the eyes.

Why-To prevent a possible hydrogen oxygen concentration from exploding when a flame is lit.

8.

Be sure to shut off the power when changing or repairing plugs or receptacles that are connected to the charging equipment. This will prevent a short circuit and arcing.

Why-A short circuit may injure you. Arcing may cause explosion and fire.

9.

Before removing the terminal lugs from the receptacle when repairing a damaged or dirty plug or receptacle connected to a battery, the battery circuit must be opened or "broken".

Why-The leads which terminate in the receptacle are live or "hot" with the total voltage of the battery existing across the terminals. If the terminal lugs are accidentally touched together a short-circuit or arcing will occur with its attendant danger.

10.

WARNING: When mixing acid to prepare electrolyte, ALWAYS POUR ACID SLOWLY INTO WATER and never water into acid. Always store acid in plastic or glass container.

Why-If water should be added to acid it will not readily mix and will splash the acid due to the great difference in the specific gravity of the two liquids. The effect of splashed acid is dangerous.

11.

WARNING: Always lift batteries with mechanical equipment such as a hoist, crane or lift truck. Move batteries horizontally with power tracks, conveyors or rollers. Make sure that hoist hooks, spreader bars and other tools are of ample strength and properly installed. Cover top of battery with rubber mat or other insulating material to prevent external short-circuits from chains or cables falling on top of battery.

Why-Batteries are a heavy concentrated load and might easily cause painful strains or injury to your feet or hands. Batteries may be seriously damaged or electrolyte spilled if the battery is dropped.

12. Make sure that charging plugs and receptacle are properly locked and all other connections tight, secure and free from friction.

Sheet 13: Battery Charging System Why-A loose connection may mean sparking or even arcing with attendant danger of gas explosion.

13. Allow only authorized personnel (qualified by training and experience) in the battery room.

Why-An untrained or inexperienced person may unknowingly break normal rules for proper handling, causing injury to themselves and damage to batteries and equipment.

14. Enclose all bare wires and buss bars in the battery room by wire guards, guard rails or other means of isolation from general plant traffic.

Why-Any open high current transmission equipment is a possible hazard to you, other workers and equipment.

15. Never lay metal tools such as wrenches or other material on top of an open battery.

Why-Sparking and short-circuiting will occur and the battery will quickly be discharged or may explode.

16. Check batteries for cracks or leaks. Repair at once.

Why-Electrolyte will spill on floor or equipment, causing corrosion of the steel tray and related equipment. Continuous flow of leaking electrolyte can cause a ground bath that reduces battery life and capacity.

17. When batteries are disposed of as scrap at the end of useful life, they should be sent to a authorized recycling center or salvage dealer.

Why-Even an old battery no longer capable of useful life may have enough residual voltage left to cause a spark if filled with electrolyte.

18. Familiarize yourself as completely as possible with batteries and the proper rules for their charging, handling and maintenance.

Why-Full knowledge of batteries and the dangers of improper handling will pay dividends in the elimination of injuries and damage.

CAUTION: Keep vent plugs in the cells at all times, except when taking hydrometer readings, adjusting specific gravity and electrolyte levels, troubleshooting or assembling a repaired cell.

NOTE: Your company, industry and government safety regulations should be reviewed to help reduce accidents and damage to equipment.

NOTE: If batteries are not in use, keep them charged. Check specific gravities monthly and give a freshening charge (3 to 4 hours at the finish rate) if the gravities have fallen 30 points (0.030) or more, otherwise, give freshening charge every three months.

LEAD-ACID BATTERIES A lead-acid battery converts chemical energy into electrical energy. The battery is discharged when the chemical reaction has occurred and the battery will not supply its rated voltage and current. A reverse chemical action must occur so that the battery can be used again. The batteries can be charged by an electric voltage and current from an outside source to provide the reverse chemical action. The lead-acid chemicals store the electrical energy until needed.

A lead-acid battery is made from several lead-acid batteries called cells. Each cell has positive and negative plates with dielectric spacers between each plate. All of the plates are in a solution of electrolyte.

Specific Gravity The strength of the electrolyte is measured in points of specific gravity. For example, a solution of sulfuric acid has a specific gravity of 1.835. Water has a specific gravity of 1.000. Electrolyte is 27% acid and 73% water and has a specific gravity of 1.275.

CAUTION: NEVER pour water into acid. The quick production of heat can cause the acid to boil and splash out

Sheet 13: Battery Charging System of the container. ALWAYS pour acid into water when making a dilute solution of acid.

Figure 9-2 - Fully Charged Cell Chemical Reaction The cell generates a voltage (potential difference) when two different types of metal are in the electrolyte. The two metals in a lead-acid cell are lead peroxide (Pb03) for positive plates, and sponge lead (Pb) for negative plates. A potential difference of approximately two volts per cell is generated. The potential difference does not vary according to the size of the cell.

During the discharging of the cell, lead peroxide and sponge lead mix with sulfuric acid to make lead sulfate (PbS04) on both plates. This action decreases the voltage in the cell. When the sulfuric acid is removed from the electrolyte, the specific gravity of the electrolyte decreases. The potential difference of a discharged cell is approximately 1.75 volts.

Figure 9-3 - Cell Discharging When a direct current is applied to a discharged cell, the lead sulfate is changed into lead and sulfuric acid. The lead goes to the positive plate and stays as lead and to the negative plate and stays as lead peroxide. The concentration of sulfuric acid in the electrolyte increases. The specific gravity of the electrolyte increases as the concentration of sulfuric acid increases. In a fully charged cell, the positive plate again contains the lead peroxide and the negative plate contains the sponge lead.

Sheet 13: Battery Charging System In a fully charged cell, the electrolyte has a specific gravity of 1.270 to 1.130. NEVER discharge a battery below a specific gravity of 1.130. The battery can have permanent damage if discharged below 1.130.

Figure 9-4 - Discharged Cell

Figure 9-5 - Cell Charging

HOW TO SELECT THE BATTERY The battery needed to operate a period of eight hours depends on many conditions. Operations that require the lift truck to go up ramps or require the use of additional attachments increases the use of power from the battery. Some work conditions require that more than one battery must be used during a work period. The number of eight hour work periods per day is normally equal to the number of batteries needed. The capacity of the battery you need is found as follows:

Sheet 13: Battery Charging System •

The size of the lift truck and the attachments.

•

The type of work. Heavy duty operation or normal operation for one eight hour work period.

The battery voltage you need is found as follows: •

Will your lift truck operate on more than one voltage?

•

If you have more than one lift truck in operation, do the battery voltages need to be the same?

Lift trucks are available in various voltage ranges. The small "Motorized Hand" trucks are normally 12 to 24 volts. Larger "Sit-Down Rider" lift trucks are normally 24 to 48 volts.

Voltage of a Battery To reach the necessary battery voltage, the cells are connected in series. For example: •

24 volts 12 cell battery

•

36 volts 18 cell battery

•

48 volts 24 cell battery

Figure 9-6 - Cell Voltage Battery Ratings The ratings of batteries are measured in ampere-hours (AH) and kilowatt-hours (KWH) at a constant rate of discharge. The number and size of plates increases the amp-hour rating. A rating of six hours is the standard. Ampere-hours is the measurement of battery capacity. To calculate ampere-hours, multiply amperes by hours. For example, 5 amperes times 5 hours is 25 ampere-hours. You cannot change the potential difference of a cell. You can increase the ampere-hour rating by increasing the number of plates in a cell, or by installation of larger plates. The constant rate of discharging can be compared to a measurement of the battery capacity and ampere-hours. For example, a battery with a rating of 600 ampere-hours during a work period of six hours will generate 100 amperes per hour for six hours. (The same battery cannot generate 300 amperes for two hours. The heat generated with the battery will damage the battery.)

Kilowatt Hours

Sheet 13: Battery Charging System A kilowatt is 1000 watts. A watt is a measure of electric power. The capacity in kilowatt-hours is the total power generated by the battery. Watt-hours are measured by multiplying the voltage by ampere-hours. To measure the kilowatt-hours, divide the watt-hours by 1000.

To calculate the kilowatt-hours for a battery that has a rating of 600 ampere-hours and a 48 volt system, use this formula.

All the electrical operations figure a specific watt-hours in electric energy. These operations include distances, loads, ramps, lifting heights, attachments, etc. The watt-hours can be converted to kilowatt-hours to indicate the battery needed for the operation. Always select the correct type of battery. Remember, a battery that has a rating of 300 ampere-hours will not do the same job as a battery that has a rating of 600 ampere-hours. Do not permit the specific gravity to go below the limits shown in the manual.

THE BATTERY AS A COUNTERWEIGHT On electric lift trucks that use the battery as part of the counterweight, the battery is part of the capacity of the lift truck to lift loads. The minimum weight of the battery is shown on the nameplate. If the battery is not the minimum weight, the capacity of the lift truck is reduced. If the battery used in the lift truck is less than the size of the battery compartment, blocks and spacers must be installed to hold the battery in position. The maximum allowable movement of a battery is 12.7 mm (0.5 in) from side to side and 12.7 mm (0.5 in) fore and aft. (Reference ANSI B-56.1.)

Inspect every new battery for damage. Make sure the electrolyte in each of the cells is at the correct level. Charge the battery for six hours or until the specific gravity is correct. Some new batteries may require cycling 7 to 10 times before the battery accepts a full charge. (Cycling is charging and then discharging the battery at a prescribed rate. Refer to the instructions shipped with the battery.) Make sure the battery is correctly installed in the lift truck. Use a correct spreader bar with slings to lift and move the battery.

CAUTION: Always use a spreader bar and slings that lift vertically on the lifting eyes of the battery. DO NOT use a chain or sling without a spreader bar or you will damage the battery.

Use the correct blocks or spacers to hold the battery in position in the lift truck. Make sure that the battery compartment is clean and dry. All of the vents caps must be in position when the battery is in service. If the vent caps are not installed, the electrolyte will leak, causing corrosion of the battery case and in the battery compartment.

Sheet 13: Battery Charging System

Figure 9-7 - Lifting the Battery

BATTERY MAINTENANCE Battery maintenance must include a good battery charger, a clean battery, keeping the electrolyte at the correct level, and keeping a record of the battery.

1.

Keep batteries clean and free of acid spills.

2.

Do not over discharge. Excessive discharge shortens battery life.

3.

Do not overcharge. Overcharging produces corrosion of positive grids and excessive gassing, which loosens the active material of the plates.

4.

Charge batteries in a well ventilated area to remove the explosive gases and acid fumes.

5.

Maintain electrolyte at the proper level. If low, add water. Before charging, make sure tops of plates are covered; after charge, fill to recommended level. Do not add acid.

6.

Keep batteries from freezing.

7.

Keep batteries in a charged state.

8.

Do not charge a battery with a charger that has an ampere-hour rating higher than that of the battery. This will give too high a charging current and excessive heating. Charging with a lower ampere-hour charger will cause no harm, but may require longer than 8 hours to fully charge.

Maintenance Records Always complete the Battery Inspection Report and the Daily Battery Report.

NOTE: Follow the same sequence when you record the cell number. Always begin the record with a positive cell. Follow a sequence so that the last cell is always the cell for the negative cable.

Record the beginning ampere reading of the charger each time the battery is charged. Any difference in the daily ampere reading can indicate a problem with the battery or the charger.

Sheet 13: Battery Charging System

Figure 9-8 - Battery Inspection Report

Figure 9-9 - Daily Battery Record Cleaning the Battery Keep the battery compartment clean and dry. Use a clean cloth to wash the battery with water. Dry with compressed air.

CAUTION: Do not clean the battery with steam or hot water. Do not use a high pressure hose.

Remove any electrolyte from the battery compartment to prevent corrosion. If there is electrolyte on the top of the battery, apply a solution of bicarbonate of soda. Mix a solution containing 1.1 lb (0.5 kg) of soda for every 4.22 qts (4 litres) of water. Apply the solution, then flush the solution from the battery with clean water. Wash the battery and battery compartment as needed. Six months between cleaning is the maximum recommended interval.

NOTE: If the top of the battery is wet from electrolyte, check to see if the electrolyte level is too high or the battery charger is not operating correctly.

Adding Water Some water is lost from the electrolyte of each cell during the charge and discharge cycle when the battery is in service. Check the electrolyte level daily. Some service persons check some of the cells each day so that all of the cells are checked each week.

Sheet 13: Battery Charging System If the level of the electrolyte goes below the level of the top of the separators for the plates, the cell can be damaged.

NOTE: Keeping the electrolyte level within the correct limits is the most important item of battery maintenance. Always use distilled water. If you add distilled water, wait five minutes before measuring the specific gravity with a hydrometer. Do not add distilled water to a cell during the charging cycle. The electrolyte can flow out of the cell through the fill hole. Figure 9-10 shows a general rule for the incorrect electrolyte level. See the instructions from the manufacturer of your battery for the operating level of the electrolyte.

Table 9-1 - Electrolyte Level

Figure 9-10 - Electrolyte Level Hydrometer Use a hydrometer to measure the specific gravity of the battery. Make sure there is enough electrolyte in the battery cells. A high level or low level of the electrolyte can change the specific gravity measurement. When the electrolyte level is low, the percent of sulfuric acid in the electrolyte increases. When the electrolyte level decreases by 3 mm (0.12 in) the specific gravity measurement can increase by 3 to 5 points.

When using the hydrometer, make sure there is enough liquid in the barrel to let the float move freely. The float must not touch the side, top, or bottom of the barrel for the correct method of reading the hydrometer.

Figure 9-11 - Hydrometer

Sheet 13: Battery Charging System Battery Temperature The temperature of the electrolyte will change the reading of the specific gravity. When the temperature increases approximately 6o C (10o F), the specific gravity will decrease by 0.003 points. Refer to Figure 9-12 for making specific gravity corrections.

Table 9-2 - Specific Gravity Corrections

Figure 9-12 - Battery Thermometer Never charge or discharge a battery at a rate that will raise the temperature of the electrolyte above 500°C (120° F). A temperature above this amount will damage the battery. The cells in the center of the battery are normally at the highest temperature. If the battery temperature is too hot, make sure the ventilation of the battery is increased and make sure that the charge or discharge rate is not too high. A recommendation for a battery in service is 8 hours of use (discharge), followed by 8 hours of cooling, followed by 8 hours of charging.

The normal electrolyte temperature is 25o C (77o F). At this temperature the electrolyte has a specific gravity of 1.285-1.295 with no correction for temperature. If the hydrometer you are using does not have a temperature correction, you will have to use a thermometer. Special battery thermometers are available that will indicate the correction factor directly and add or subtract the correct number of points.

CHARGING THE BATTERY

Sheet 13: Battery Charging System WARNING: Batteries produce explosive hydrogen gas when charging. Always open the battery cover or hood and provide good ventilation when charging.

To charge the battery, a direct current must pass through the cells in the opposite direction to the discharging current. The ampere-hours must be equal to the discharging ampere-hours plus the energy lost as heat. This additional amount of charge will vary according to the battery and the temperature, but the average additional charge is 12%. When the battery is nearly charged, the final charging must be at a low rate. A charging rate that is too high will cause heating in the battery and a high loss of water from the electrolyte. The charging of the battery must be done correctly or the service life of the battery will be decreased.

NEVER discharge a battery below 1.130 to 1.110. Discharging a battery beyond the design limits will decrease the service life of the battery.

If lift truck operation results in only partial discharges (50% or less) and specific gravities are 1.210 to 1.220 or more at the end of the shift, recharging may be deferred and the battery used for another shift providing the work load is not expected to increase. Hydrometer readings and experience will disclose the frequency of charge intervals under these circumstances.

CAUTION: A battery should always be recharged immediately following a complete discharge. Never allow it to remain in a discharged condition, since permanent damage may result.

Types of Battery Charges 1.

DAILY CHARGE-This charge is normally eight hours and will keep the battery fully charged if the battery is not discharged below the limit.

2.

EQUALIZING CHARGE-This charge is at a low rate and balances the charge in all of the cells. The equalizing charge is normally given approximately once per week and is three hours at a low rate in addition to the regular charging cycle. The most accurate specific gravity measurements for a charged battery will be after an equalizing charge.

NOTE: Sometimes the capacity of a battery is not enough to complete a work period. Check for the following conditions: •

The battery is too small for the job.

•

The battery is not fully charged.

•

The battery charger is not operating correctly.

•

The battery is near the end of its service life.

Methods of Charging There are three methods of charging a battery.

1.

GRADUAL CHARGE-This method uses a solid state automatic battery charger. The charging rate begins at 20-25 amps/100 amp-hours and decreases to less than 5 amps/100 amp-hours when the battery is 80% charged. The charging current decreases when the voltage across the cell increases during the charging cycle. The increase in the voltage from the charger is approximately the same as the increase in the specific gravity in the cells.

2.

MODIFIED CONSTANT VOLTAGE-This method uses a generator to generate a constant voltage that is controlled by a resistor. When the charging current decreases, the voltage across the resistor causes an increasing voltage at the battery terminals. The charging is similar to the gradual charge. The resistor must be correctly set or the charging rate will be wrong.

3.

TWO-RATE CHARGE-This method also uses a high charging rate at the beginning followed by a lower rate. Two resistors control the charging rate. One resistor controls the charging rate at the beginning of the cycle and a second resistor reduces the charging rate when the voltage in the cells reach 2.37 volts. A relay automatically controls the second resistor.

Troubleshooting the Charger Battery chargers normally operate automatically without constant attention. It is necessary to make a periodic check to determine if the charger is operating correctly. Check for the following conditions:

Sheet 13: Battery Charging System 1.

Battery temperature is too high-The temperature in a battery will not normally rise more than 14o C (25o F) during an eight hour charging period. Higher temperatures indicate that the charging rate needs adjustment.

2.

Continuous operation of the charger-Check the automatic controls on the charger. Check the charging rate. A low charging rate can be the problem.

3.

Continuous operation of a charger at a high rate-Normally, the charging rate begins at a high rate and decreases as the battery becomes charged. If the rate does not decrease, the control need repair or adjustment.

WARNING: Always connect the positive cable to the positive terminal and connect the negative terminal. Any other connection will cause injury and damage.

WARNING: Always charge the battery at the end of the work period (shift). Never let the specific gravity reach a level less than the limits shown in the manual.

WARNING: Always deenergize the charger before you connect or disconnect the charger from the battery.

How to Know when the Battery is Fully Charged 1.

During charging, the voltage increases slowly. When the battery is fully charged, the voltage level is constant.

2.

Remove a vent cap and look in the opening. If you see bubbles in the electrolyte, the battery is either fully charged or in the final stage of charging.

3.

The specific gravity reading is constant and within the limits of a charged battery. If the temperature increases after the battery is charged, the specific gravity will decrease a small amount.

4.

Constant meter indications on the charger will indicate the end of the charging cycle.

Battery Charging Area To increase the service life and reduce maintenance, a special area is needed for charging the batteries. The following information should be considered when setting up an area.

1.

Location of power supply.

2.

Ventilation. Hydrogen gas comes from the batteries during charging.

3.

Drains for cleaning the batteries.

4.

Type and size of the batteries.

5.

Type of lift truck.

6.

Distances that the lift trucks must travel for service.

7.

Safety regulations and instructions.

Equipment Needed •

A lifting device to remove the battery from the lift truck.

•

Racks to hold the batteries during charging and storage. These racks must be made of wood and must not be metal unless the metal racks are covered with an insulating material.

•

A battery charger that will charge your batteries.

•

Tools for maintenance.

Sheet 13: Battery Charging System •

An area with a drain for cleaning batteries and battery compartments.

•

Distilled water.

•

Air and water supplies for cleaning.

•

Maintenance records.

•

A work bench.

•

Spare parts and repair equipment.

•

Protective clothing and safety equipment for handling batteries.

•

Water sources for washing eyes and preventing acid burns.

•

Install a NO SMOKING sign in the service area.

•

Keep the charger in a clean, dry area with good ventilation.

TROUBLESHOOTING-BATTERY

Sheet 13: Battery Charging System

Sheet 13: Battery Charging System