PDF Download: Yale A824 Forklift (ESC020_25_030AB) Service Manual

Curtis Motor Controller--ESC AB CURTIS MOTOR CONTROLLER - GENERAL The electrical system of the ESC-AB truck model has undergone continuous improvement and modernization. This manual contains maintenance information for late production models equipped with the Curtis Transistorized Motor Controller and associated components. Check the truck model code and serial number before performing any work to determine the proper procedures and maintenance information applicable to the truck to be repaired.

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 truck. 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.

WARNING: The capacitor in the motor 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 motor 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. Refer to the Maintenance Manual or Operating Manual for instructions on how to put a lift truck on blocks. The blocks must prevent the lift truck from falling and causing injury or damage.

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.

NOTE: Refer to the wiring diagrams and schematics at the end of this section for additional information.

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

CHECKS 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 lift truck half of the battery connector and a clean connection on the frame. Remove any circuit paths between the connector 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 battery half of the battery connector 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.

Curtis Motor Controller--ESC AB

Figure 1 - Basic Traction Motor Circuit

Curtis Motor Controller--ESC AB

Figure 2- Control Panel

Curtis Motor Controller--ESC AB

Figure 3 - Transistor Motor Controller

TRANSISTOR MOTOR CONTROLLER General The traction motor is controlled by a Curtis Transistor Motor Controller also known as a MOSFET or PMC controller.

The controllers used in trucks covered by this manual will vary depending on truck voltage. Refer to the appropriate parts manual to identify the specific motor controller used on the truck to be serviced.

The motor controller is used to regulate the speed of the traction motor. The motor controller applies battery voltage in short fast pulses to the DC motor to control the speed. The direction of rotation of the traction motor is controlled by forward and reverse contactors.

The motor controller is sealed in an aluminum case and cannot be repaired. The complete unit must be replaced if correct troubleshooting methods indicate that the unit is damaged.

In addition to controlling the movement of the truck the motor controller performs the following functions: a. Monitors temperature to provide high and low temperature protection to the motor controller. b. Checks that an operator follows the correct starting sequence to help prevent unexpected operation. This function is called "Static-Return-To-Off" (SRO). c.

Checks the traction circuit for malfunctions and 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.

Refer to the Wiring Diagrams and Schematics at the rear of this section for connection information.

Control The control circuit receives operator inputs from the key switch the brake switch and the accelerator potentiometer.

The circuit receives internal inputs from the power circuit for thermal protection plugging sensing low voltage protection and motor current (current limit). The control circuit regulates speed control current limit and plugging strength.

Plugging The plugging circuit provides smooth electrical braking and saves wear and tear on the drive tires and the drive unit gears. Plugging occurs when the truck is traveling in one direction and the operator switches the directional control to the opposite direction. Avoid plugging the drive motor when the drive wheel is jacked off the ground.

The plugging function is designed to allow the truck to travel 1 to 2 times the length of the lift truck before the truck reverses direction after the directional control is switched to the opposite direction. The plugging distance is adjustable. Refer to ADJUSTMENTS this section.

Curtis Motor Controller--ESC AB Static-Return-To-Off (SRO) The SRO function prevents the operation of the lift truck when the starting sequence is not performed in the correct order. The starting sequence is as follows: a. Turn the key switch to the ON position. b. Step on the brake pedal to release the brake and close the brake switch. 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 steps (a.) and (b.) are done the truck will not move in either direction. The key switch and brake switch must close before either direction switch closes. If the switches do not close in the proper sequence the truck will not operate.

High Pedal Disable The HPD function prevents the lift truck from operating when the accelerator potentiometer is engaged above creep speed prior to the closing of the key switch and brake switch. The circuit will return to normal operation when the signal from the accelerator potentiometer is reduced to the creep speed range or below.

Thermal Protection If the temperature sensor in the motor controller become too hot or too cold for correct controller operation the control circuit will decrease current to the controller. The lift truck will operate at a slower speed to permit movement out of the work area. When the controller temperature returns to the normal range full power is restored.

Low Voltage Protection The motor controller and the battery are protected from a low voltage condition. For example a 24 volt motor controller requires at least 16 volts to function properly. The battery current drain increases as the battery voltage decreases. If the battery voltage is low the control circuit decreases the current drain. The truck will operate enough to move it for battery charging or replacement.

Current Limit The control circuit limits the traction motor current to a maximum value to protect the motor controller motor and battery. The maximum value is set by the manufacturer.

Motor Controller Replacement Identify and disconnect the wires and cables from the motor 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 motor controller. Install the replacement controller on the lift truck. Connect the wires and cables to the same terminals as identified during the removal procedure.

Curtis Motor Controller--ESC AB

Figure 4- 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 Motor controller is damaged at FWD or REV terminal.

Curtis Motor Controller--ESC AB

FAULT NUMBER 2.

DIRECTIONAL CONTACTORS WILL NOT CLOSE FOR OPERATION IN EITHER DIRECTION Possible Causes: • Battery not connected • Control fuse is damaged • FIR switch is damaged • Motor controller is damaged • Static-Return-to-Off (SRO) invoked of control fuse • Key switch or brake switch is damaged • Traction reverse switch is damaged • Battery voltage is low • Wires in circuit are open

Curtis Motor Controller--ESC AB

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 • Accelerator potentiometer damaged or needs adjustment • Damaged (open) traction motor cables • Motor controller is damaged • Hi-Pedal Disable (HPO) invoked

Curtis Motor Controller--ESC AB

FAULT NUMBER 4.

DIRECTIONAL CONTACTORS CLOSE, LIFT TRUCK ACCELERATES TO FULL SPEED IMMEDIATELY. Possible Causes: • Motor controller is damaged • Accelerator potentiometer damaged or needs adjustment

Curtis Motor Controller--ESC AB

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 truck. 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.

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.

Curtis Motor Controller--ESC AB 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. Adjust the motor controller as required using a small insulated screwdriver. e. Install the socket head screws after the proper adjustments have been made. Install the compartment cover and connect the battery cable. Test the truck for proper operation before returning the truck to service.

WARNING: The capacitor in the motor 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 motor controller.

Plugging Adjustment Turn the plugging (braking) adjustment screw clockwise to increase the plugging effect and stop the lift truck in a shorter distance. Turn the adjustment screw counterclockwise to decrease the plugging effect. The traction motor generates more heat and the motor brushes wear at a faster rate when the motor controller is adjusted for a shorter stopping distance (increased plugging). The default or factory setting is obtained when the adjustment screw is set in the one o'clock position.

Acceleration Adjustment Turn the adjustment screw counterclockwise to decrease the rate of acceleration. Turn the acceleration adjustment screw clockwise to increase the acceleration rate. The traction motor generates more heat and the motor brushes wear at a faster rate when the motor controller is adjusted for an increased acceleration rate. The default or factory setting is obtained when the adjustment screw is set in the twelve o'clock position.

Current Limit Adjustment The current limit adjustment is factory-set at the maximum 400 amps. Increasing the current limit can cause damage to the motor controller or the traction motor and can cause the truck to run at a higher than normal speed especially when driven unloaded. Decreasing the current limit can affect the starting torque and can cause the truck to run at less than top speed when fully loaded. The current limit setting should remain at the factory setting. If necessary turn the current limit adjustment screw counterclockwise to decrease the current limit or clockwise to increase the current limit.

If it 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. b. Remove the compartment cover and discharge the capacitor. c.

Remove the 3 mm (o.12 in) socket head screws to access the adjustment screws.

d. Adjust the motor controller as required using a small insulated screwdriver. e. Install the socket head screws after the proper adjustments have been made. Install the compartment cover and connect the battery cable. Test the truck for proper operation before returning the truck to service.

Curtis Motor Controller--ESC AB

Figure 5- Motor Controller Adjustment Locations

DIRECTIONAL AND SPEED SWITCH ASSEMBLY Accelerator Potentiometer Adjustment 1. Move the key to the OFF position. Disconnect the battery.

2. Mark the wires for identification before disconnecting the wires from the switches. Remove the connector to the potentiometer and the connector to the switches.

3. Remove the control handle from the truck.

4. Test the potentiometer using an ohmmeter (RX100 scale). 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 and then to the reverse direction. The meter should indicate less than 100 ohms at maximum travel in either direction.

5. Center the potentiometer using the ohmmeter as follows: Position the control in neutral. Loosen the setscrews retaining the gear on the potentiometer. Insert a narrow blade screwdriver through the front wall of the potentiometer mounting bracket and into the slotted end of the potentiometer shaft. Rotate the potentiometer shaft slowly clockwise then slowly counterclockwise until the midpoint of the potentiometer is located. Tighten the retaining setscrews when the midpoint is obtained. If the correct readings cannot be obtained the potentiometer must be replaced.

6. Install the two connectors.

7. Install the control handle in the truck. Install the cover.

Curtis Motor Controller--ESC AB 8. Connect the battery turn the key to the ON position and test the lift truck for proper operation before returning the truck to service.

Cam Adjustment 1. Move the key to the OFF position. Disconnect the battery.

2. Mark the wires for identification before disconnecting the wires from the switches. Remove the connector to the potentiometer and the connector to the switches.

3. Remove the control handle from the truck.

4. Center the cams as follows: Position the control in neutral. Loosen the setscrews retaining the actuator to the shaft. Insert a narrow blade screwdriver through the rear wall of the potentiometer mounting bracket and into the slotted end of the shaft. Rotate the shaft slowly clockwise then slowly counterclockwise until both switches are in the "off" position. Check that the same amount of angular travel of the shaft is required to actuate both switches.

Tighten the retaining setscrews.

Figure 6- Directional and Speed Switch Assembly

CONTACTORS A contactor is a switch controlled by an electromagnetic coil used to close or open a power circuit. Electronic drivers in the motor controller send electric current to the electromagnetic coil in the contactor. The electromagnetic field produced by the current flow to the coil causes the power circuit contacts to move against spring pressure to open or close the power circuit of the contactor. When the electromagnetic coil is deenergized the spring pressure moves the power circuit back to the original or normal position. Power circuit contacts of a contactor are called Normally Open (NO) or Normally Closed (NC) referring to the position of the contacts when the electromagnetic coil of the contactor is not energized. When spring pressure holds the power circuit contacts in the open position the circuit is called Normally Open. When spring pressure holds the power circuit contacts in the closed position the circuit is called Normally Closed (NC). When the contactor coil is energized the spring pressure is overcome by the electromagnetic field to switch the contacts from their normal position to the opposite position. A single contactor may contain both normally open and normally closed power circuit contacts.

The power circuit contacts are made of special silver alloy. The contacts normally look black and rough. This condition does not indicate problems with the contactor nor does it affect the operation of the lift truck. Cleaning is

Curtis Motor Controller--ESC AB 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.

The direction of rotation of the traction motor is controlled by the FORWARD/REVERSE contactor assembly. The contactor assembly consists of two contactors one forward and one reverse. Each contactor has two sets of normally open (NO) contacts two sets of normally closed (NC) contacts and an electromagnetic coil. 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.

Testing Contactors WARNING: Parts of this procedure requires working on the lift truck with full electric current present. Do not wear any rings watches or other jewelry while working around the contactor panel. Use a properly insulated tool when manually closing a contactor with power connected.

1. Block the lift truck so that the drive wheels are off the floor. Refer to the Operator's Manual for specific instructions. Make certain that the hydraulic controls are in the neutral position.

2. Remove the drive unit compartment cover.

WARNING: Never operate the traction motor at full speed for more than a few seconds when the drive wheels are off the floor. A series wound DC motor will continue to accelerate indefinitely until it exceeds the designed maximum rpm at which point it will self-destruct. Personal injury or damage to the lift truck can occur.

3. Check the condition of the battery. If it is not fully charged replace the battery with a fully charged battery.

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 should not be loose.

7. Visually check the tips for pitting burning or wear.

8. Disconnect the battery. Disconnect the contactor coil wires. Measure the resistance of the 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 when measured in one direction compared with the other direction. Measure the resistance in each direction. Use the highest resistance indication. When testing the coils for the forward and reverse contactors the ohmmeter should read 18 ohms 10%. When testing the coils for the lift and lower contactors the ohmmeter should read 50 ohms 10%. Replace the coil if the resistance readings indicate a short-circuit or an open circuit in both directions.

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 bus 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 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 or incorrect size or mismatched tips.

Curtis Motor Controller--ESC AB

Figure 7- Power Steer Contactor

Curtis Motor Controller--ESC AB

Figure 8 - Lift Pump Contactor Contactor Replacement 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.

WARNING: The capacitor in the motor 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 motor controller.

Curtis Motor Controller--ESC AB NOTE: Make an identification of wires before disconnecting to ensure the wires are connected properly after checks or repairs are performed.

1. If the lift truck has an "EE" rating, remove the cover of the contactor box for access to the contactor terminals.

2. Make an identification of the wires and cables and disconnect them from the contactor assembly.

3. Remove the mounting screws and replace the contactor assembly.

4. 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 the coil of a contactor need to be replaced, replace the complete contactor as described above. Replace all of the contacts for any contactor if any contact needs replacing.

1. Remove the contactor as described in CONTACTOR REPLACEMENT. 2. Make an identification of the bus bars for correct installation. Remove the bus bars and nuts that fasten to the fixed contacts.

3. Remove the two screws that fasten the cover to the contactor. Remove the cover of the contactor. Do NOT lose the plunger springs.

4. Replace the four fixed contacts in the contactor cover.

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

6. If the coil will be replaced, remove the cover base. Remove the screws that fasten the coil frame to the mount bracket. Remove the coil and frame. Remove the bushing part of the plunger and the armature cap from the coil. Install these parts on the replacement coil.

7. Install the coil and frame on the mount bracket.

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

9. Install the contactor cover.

10. Install the contactor on the lift truck.

11. Install the contact carrier, the lower fixed contact bars and the lower clamps.

Curtis Motor Controller--ESC AB

Figure 9- Forward and Reverse Contactor

Curtis Motor Controller--ESC AB

Figure 10 - Wiring Schematic 5850561-00 - Curtis Transistor Control - Type "E"

Curtis Motor Controller--ESC AB

Figure 11 - Wiring Diagram 5850561-00 - Curtis Transistor Control - Type "E"

Curtis Motor Controller--ESC AB

Figure 12 - Options Diagram 5850561-00 - Curtis Transistor Control - Type "E"

Curtis Motor Controller--ESC AB

Figure 13 - Wiring Schematic 5850569-00 - Curtis Transistor Control - Type "EE"

Curtis Motor Controller--ESC AB

Figure 14 - Wiring Diagram 5850569-00 - Curtis Transistor Control - Type "EE"

Curtis Motor Controller--ESC AB

Figure 15 - Options Diagram 5850569-00 - Curtis Transistor Control - Type "EE"

Curtis Motor Controller--ESC AB

Figure 16-Wiring Schematic 5850571-00—Freezer/Cold Storage/Corrosion Modification

Curtis Motor Controller--ESC AB

Figure 17-Wiring Diagram 5850571-00—Freezer/Cold Storage/Corrosion Modification

Curtis Motor Controller--ESC AB

Figure 18-Options Diagram 5850571-00—Freezer/Cold Storage/Corrosion Modification

Sheet 8: Battery Charging System

BATTERY AND CHARGING SYSTEM INSTALLATION AND OPERATING INSTRUCTIONS 1.

Placing in Service

Remove vent caps from each cell and determine whether. electrolyte level in all cells is at least half way between the element protector and the bottom of the cell cover vent well. If electrolyte has been lost, replace with electrolyte of the same specific gravity as found in other cells of the battery. Replace vent caps and give battery a freshening charge of 3 to 6 hours or by continuing the charge until there is no increase in specific gravity for three hydrometer readings taken at one hour intervals. The normal fully charged specific gravity is 1.280 to 1.290 at 77°F. 2.

3.

Safety a.

Wear rubber apron, gloves, boots and goggles or face shield when handling, checking, filling, charging or repairing batteries.

b.

Keep open flames away from storage batteries; do not check electrolyte level with a cigarette lighter or match. Use flashlight or permanent lights. Do not smoke or create sparks.

c.

Lift batteries with hoist, crane, lift truck or similar equip-ment; move batteries on industrial trucks, conveyors or rollers.

When handling batteries without covers, a rubber mat or similar insulating material should be placed across the top of the battery to prevent acci-dental shorts. Make sure rifling equipment is of ample strength and properly installed. Do not use chain or wire rope slings.

d.

Never lay metal tools such as wrenches or other material on top of a battery.

e.

Disconnect battery from the truck when performing maintenance and repair on motors or electrical system.

f.

When work on the battery and battery charger circuits is required, disconnect the A. C. and D. C. power. If the battery connectors are replaced, keep the positive and the negative terminals separate and insulated from one another.

Even momentarily touching them together could cause an explosion or damage to the battery.

g.

Keep water readily available for flushing spilled electrolyte from eyes. Use plain water only and obtain medical attention immediately. Special deluge showers and eye wash basins are required.

h.

Apply strong neutralizer like baking soda when acid is spilled on the floor; clean up promptly.

i.

Familiarize yourself with batteries and rules for charging, handling and maintenance.

j.

Only properly trained personnel should be assigned to battery and charger care.

k.

Review your company safety regulations and familiarize yourself with industry and government guidelines (OSHA, ANSI, etc.) to help reduce accidents and equipment damage.

Operation

Batteries are rated in ampere hours and are selected to perform a specific work load within an established period of time.

Increasing the work load or time period could result in overdischarging, thus shortening battery life. Limit discharging of battery so that specific gravities do not go below 1.140 to 1.100.

If 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.

A battery should always be recharged immediately follow-ing a complete discharge. Never allow it to remain in a discharged condition, since permanent damage may result.

4.

Charging

When recharging a fully discharged battery, the starting charge rate may be 3 to 5 times higher than the finish charge rate indicated on the battery nameplate. The charge rate should taper down to the finish charge rate by the time the battery is 85% charged and may be even lower when fully charged. High "on charge" temperatures or frequent need for water additions are

Sheet 8: Battery Charging System indications of overcharging. Consult your Yale dealer on specific charging problems. Keep vent caps in place during use and charging.

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 (.030) or more; otherwise, give a freshening charge every three months.

5.

Maintenance (Cleaning)

The top of the battery should be kept clean and dry. Remove vent caps only to observe levels, make water additions, take temperatures or take specific gravity readings with a hydrometer. The battery can be washed off with water if dusty. Keep vent caps in place. If electrolyte has accumulated on top, wash with a neutralizing solution of soda and water (one pound of baking or commercial soda ash to one gallon of water). Follow with a rinse using clear water.

Figure 8-1—BATTERY CONNECTOR ITEM DESCRIPTION 1.

2.

3.

6.

Battery Connector Case Contacts Spring Retainers

Water Additions

Maintain the electrolyte levels half way between the element protector and the bottom of the cell cover vent well, but never below the protector or higher than the bottom of the vent well. Add only distilled or approved water. Check electrolyte level daily, prior to charging on at least one cell, and weekly on all cells.

7.

Service

Additional information and assistance can be obtained from your Yale dealer.

BATTERY CONNECTOR SERVICE Removal of the contacts from the case is accomplished by depressing the spring retainer with a small screwdriver and pul-ling on the wire. Remove one contact at a time to prevent acci-dental shorts. The two halves are interchangeable and can be color coded to the battery charger. The wires should be soldered in completely to ensure a good electrical connection.

When installing battery connectors to battery cables, do one side at a time. This will help to prevent the possible accidental shorting of the positive and negative terminals.

BATTERY INSPECTION The battery case should be examined for rough handling and leaking. Check the battery for proper electrolyte level and state of charge. The electrolyte level should cover the top of the per-forated shield just below the vent well.

A fully charged lead acid battery has a specific gravity of 1.280. Verify that the voltage at the battery plug is correct in both magnitude and polarity. Be sure the battery fits properly in its compartment. Check water levels daily. Add only approved or distilled water.

Keep open flames and sparks away from the battery, especially during charge, as gases given off are explosive. Batteries should be kept clean and dry at all times. Information relating to the care and maintenance of the batteries can also be found in the literature shipped with the battery.

Sheet 8: Battery Charging System Battery should be fully charged and electrolyte should be at the proper level. If battery is not in the truck when received, care should be exercised when placing battery in its compartment. See that it sits solidly within the compartment. Be certain polarity of battery is correct. Join the battery connector with that of truck mounted on battery compartment. Be sure connectors are pushed down to full extent to ensure proper contact. This is important, as loose connectors will produce heat and burn the contacts.

BATTERY CHARGERS The storage battery that powers your lift truck normally will be placed on charge after each shift. If you are responsible for con-necting and disconnecting the truck to the charger, follow these suggestions: 1.

Be sure the charger is turned off before touching the charger cable. Attempting to disconnect the cable while the charger is operating may result in damage to the cable and injury to you.

2.

If the charger is still on when you are ready to begin your duty cycle, the battery may not have received the proper charge.

3.

When you are sure the charger is off, disconnect the bat-tery from the charger. Before connecting the battery lead to the truck receptacle, make sure the truck controls are in neutral and that the connector is firmly in place.

For complete charging instructions, refer to the manual supplied with the battery charger.

SAFETY TIPS FOR HANDLING INDUSTRIAL TRUCK BATTERIES 1.

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.

2.

Keep open flames away from batteries—do not check electrolyte level with a cigarette lighter or match. USE A FLASHLIGHT OR ADEQUATE PERMANENT LIGHTS. 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 that is flammable and can explode.

3.

Be sure water is readily available in case electrolyte acci-dentally 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.

4.

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.

5.

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 screw driver or other sharp tool. DO NOT ALLOW COMPOUND TO IGNITE BY TOO RAPID HEATING.

WHY—The hot liquid may squirt up and burn your hands, 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.

6.

Remove vent caps from nearby cells when preparing to reassemble 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.

7.

Be sure to shut off the power when changing or repair-ing plugs or receptacles that are connected to the charg-ing equipment. This will prevent a short circuit and arcing.

Sheet 8: Battery Charging System WHY—A short circuit may injure you. Arcing may cause explo-sion and fire.

8.

Before removing the terminal lugs from the receptacles when repairing a damaged or dirty plug or receptacle connected to a battery, the battery circuit must be open-ed or "broken. "

WHY—The leads that 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.

9.

When mixing acid to prepare electrolyte ALWAYS POUR ACID SLOWLY INTO WATER and never water into acid. Always store acid in plastic or glass containers.

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.

10. Always lift batteries with mechanical equipment such as a hoist, crane or lift truck. Move batteries horizon-tally with power trucks, conveyors or rollers. Make sure that hoist hooks, spreader bars and other tools are of ample strength and properly installed. Cover top of bat-tery 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.

11. Make sure that charging plugs and receptacle are pro-perly locked and all other connections tight, secure and free from friction.

WHY—A loose connection may mean sparking or even arcing with attendant danger of gas explosion.

12. 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.

13. Enclose all bare wires and bus bars in the battery room with wire guards, guard rails or other means of isola-tion from general plant traffic.

WHY—Any open high current transmission equipment is a possible hazard to you, other workers and equipment.

14. Disconnect the battery from the truck when doing maintenance and repair work on the motors or electrical system.

WHY—The live current may cause arcing or a short circuit with attendant damage to equipment or injury.

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 cor-rosion of the steel tray and related equipment. Continuous flow of leaking electrolyte can cause a ground path for current that reduces battery life and capacity.

17. When batteries are disposed of as scrap at the end of useful life, drain electrolyte and flush out cells with water.

WHY—Junk dealers are not familiar with batteries and use rough methods to break up batteries for lead content. 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 bat-teries 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.

NOTE: Your company, industry and government safety regula-tions should be reviewed to help reduce accidents and damage to equipment.

Sheet 8: Battery Charging System CAUTION: Keep vent plugs in the cells at all times, except when taking hydrometer readings, adjusting specific gravity and electrolyte levels, ~ troubleshooting or reassembling a repaired cell.

STATE OF CHARGE—DISCHARGE The energy of a battery, or the work that it can perform, is measured in kilowatt-hours. The kilowatt-hour rating of a battery is the product of the voltage, multiplied by the ampere-hours and divided by 1000. A 36-volt, 600 ampere-hour battery can deliver 36 x 600 -1000 = 21.6 kilowatt-hours(abbreviated KWH). One kilowatt-hour is equivalent to 2, 654, 000 ft. Ibs. of work or 1.34 horsepower hours.

If a battery is discharged beyond a certain limit, damage to the plates will result and battery life will be severely shortened. It is important, therefore, to be able to measure the state of charge of a cell.

As a cell is discharged, its voltage decreases. A fully-charged cell measures about 2.1 volts; a discharged cell measures about 1.75 volts. Measuring the battery voltage, then, provides a means of determining state of charge. Although not as accurate as other means, it is a convenient measurement. It is used in most discharge indicators found on fork lift trucks. In these devices, when the battery voltage reaches a certain level, a light is energized to signal the operator.

A more accurate measure of state of charge is specific gravity, often referred to as SG. As a cell is discharged, the acid content of the electrolyte is decreased and the water content increased. Specific gravity is a measure of the ratio of the weight of a given

Figure 8-2—Typical Cell Construction

Sheet 8: Battery Charging System

Figure 8-3—Battery Hydrometer amount of electrolyte to the weight of the same amount of water. At full charge, the specific gravity is usually 1.280 (sometimes referred to as SG of twelve-eighty). A discharged cell would have an SG of 1.120. Specific gravity is measured with a device called a hydrometer (see Figure 8-3). Electrolyte is drawn up into a glass tube that contains a float. The float has a graduated scale on its stem. For high specific gravity liquids the float will ride high in the solution. The specific gravity can be read from the scale at the surface of the solution.

Specific gravity changes with temperature, and a correction must be made if the temperature is different from that for which the hydrometer was calibrated (usually 80 F.). For each 1 0°F below this, 0.004 must be subtracted.

CHARGING A lead-acid battery is a secondary battery. It is capable of being charged and used again. To charge a battery, it is necessary to supply electric current to it from a power source having a voltage somewhat higher than the battery voltage, so that the direction of current flow is opposite to that during discharge. Because of losses, it is usually necessary in charging to supply 20% more ampere-hours than were removed during discharge.

Charging of a battery creates heat within the cells. It is important to limit this heat to a safe level to prevent internal damage to the battery. This is accomplished by limiting the charging cur-rent. The recommended starting rate is .225 amperes for each ampere-hour of capacity.

The recommended finishing rate is .05 amps per ampere-hour. A 600-ampere-hour battery, then, should have an initial charg-ing current of .225 x 600 or 135 amps, and a final charging cur-rent of .05 x 600 or 30 amps.

During battery charging, chemical action is reversed; the sulfuric acid content of the electrolyte increases the specific gravity.

Cell voltage increases also. When the charge is approximately 80% complete, a sharp rise can be observed in the cell voltage.

This occurs at about 2.35 charging volts. At this time "gassing" occurs: oxygen and hydrogen are liberated. Because of explosive nature of these gases, no open flames should be allowed in a charging area. When gassing starts, the charge rate should be reduced.

BATTERY CHARGERS—Constant Potential There are two basic types of chargers: constant potential and constant current. In the constant potential charger, a fixed voltage is applied to the battery. The charging current is determined by the difference between battery voltage and charger voltage, and the resistance of the circuit between them. As the battery voltage increases during charging, the charging current decreases. As it nears the end of charge, the current reduces to the finishing rate. Often this is done when the gassing voltage is sensed; the current is then changed abruptly to the finishing rate.

Constant Current

Sheet 8: Battery Charging System The constant current charger provides a fixed charging current, starting at about the recommended starting rate and cutting back to the finishing rate when gassing voltage is sensed. Both types of chargers are equipped with timers to prevent excess charg-ing. Usual charging time is 8 hours. An occasional 1 2-hour charge at a low rate is recommended to equalize the charge between cells.

BATTERY CARE The following is a list of items for proper battery care: 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 ex-plosive 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 amperehour 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.

9.

When moving batteries, be careful not to short-circuit battery terminals.

BATTERY TROUBLESHOOTING CONDITION CORRECTION

POSSIBLE CAUSE

Sheet 8: Battery Charging System

Sheet 8: Battery Charging System

Sheet 8: Battery Charging System

BATTERY TROUBLESHOOTING

Sheet 8: Battery Charging System

BATTERY DISCHARGE INDICATOR Curtis 933 Service Information A. Purpose: To ensure that a fully charged battery is installed in the truck.

To provide maximum work time on the shift without damaging truck components or reducing battery life.

Sheet 8: Battery Charging System To provide early warning indications of battery and truck component malfunctions.

B. What does it tell the operator?

1.

Automatic Reset tests for fully-charged battery. The "Fuel" gauge resets only if the battery is fully charged. A potentiometer on the controller allows the user to select a reset level within the range of 70% charge to full charge, to accommodate special user circumstances.

2.

"Fuel" Gauge displays the battery's state of charge, providing the operator and supervision with informa-tion on which to base their operations decisions.

3.

Reserve Warning Light indicates to the driver that the "energy reserve" point has been reached. Approx-imately 5% of battery capacity is available prior to the lift being locked out. The need for a battery charge is signalled at the optimum point in the discharge cycle, to maximize battery life and reduce maintenance and energy costs.

4.

Lift Lockout prevents damage to the battery and the truck due to the discharge of the battery beyond its "energy reserve. "

C. What should the operator do?

1.

Gauge Fails to Reset: This means the battery is not fully charged and should not be used. Have maintenance personnel check the battery and the charger. If possible, use a different battery.

2.

Warning Light Blinks: Normally return to charger station for a fully charged battery. However, the 5% "Energy Reserve" before lift lockout will permit com-pletion of urgent tasks.

D. Troubleshooting the Curtis 933/3 Battery Discharge Indicator.

Equipment required: a.

Digital Voltmeter with a minimum of .5% accuracy.

b.

Curtis #1142 Tester — Voltage ranges 12-18V, 20-48V & 50-80V are available. *

c.

(Optional)Curtis 1141 Fastest Accessory— when used with Curtis 1142 Tester, discharge testing is reduced from 30 minutes to 1 minute.

'These testers may be ordered from Yale Materials Handling Corporation—Attention Customer Service.

Request current pricing when ordering. Specify desired voltage range when ordering Model 1142 Tester.

Directions for meter usage are supplied with meter.

1.

SYMPTOM: Gauge does not reset to "full, " with a fully charged battery. a.

Check battery voltage across controller terminals 1 and 8 (see Figure 8 4). No current should be flow-ing from the battery at the time. For example, if the voltage is greater than 25.3 volts, for a 24-volt battery or 38 volts for a 36-volt battery, the gauge should reset.

b.

Before replacing the controller, check that the reset potentiometer is at "B". If not, set the potentio-meter to "B", disconnect the battery for 15 seconds and reconnect. If reset is not achieved, replace the controller.

c.

If battery voltages are less than the values above, the following problems can exist: 1.

Sulfuric acid levels In the battery may be below those recommended by the manufacturer.

2.

Insufficient time on the charger to bring the battery up to full charge.

3.

Battery has shorted cell or cells.

d.

While corrective action is being taken, the battery can be used but with reduced capacity and shorter work time for the truck.

e.

To use the battery, proceed as follows.

1.

Turn reset potentiometer to "A".

Sheet 8: Battery Charging System 2.

Disconnect the battery for 15 seconds.

3.

Reconnect the battery. The gauge will go to "full" if the battery voltage is greater than 2.06 volts per cell (1210 SG).

CAUTION: After corrective action has been taken with the battery or charger, be sure to turn the controller reset potentiometer to "B".

2.

SYMPTOM: Lift is not locked out. a.

Remove the wire from pin 6 of the controller and operate the hoist lever.

b.

If hoist works, the problem is in the truck wiring.

c.

If hoist does not work, replace the wire on pin 6. Connect the 1142 or 1141 and 1142 tester.

d. Run the gauge to empty (red ball). Verify gauge light is blinking. Hoist should not work. If it does. replace the controller and gauge.

3.

SYMPTOM: Gauge moves erratically or bounces. a.

The probable cause is noise pickup from an unsup-pressed contactor coil. Check suppression circuits on all contactor coils, and replace any defective circuits.

b. If all suppressor circuits check out all right, replace the controller and gauge.

4.

SYMPTOM: Lift lockout occurring unusually early. a.

The condition is only pertinent after the truck has been operating successfully for several months with the fuel gauge.

It's a report from the driver or maintenance people that conditions have changed.

b.

High resistance in the truck to battery connector.

c.

1.

Run the lift motor and check the voltage at ter-minals 1 and 8 of the controller.

2.

The readings should be within .5 volts of each other. If not, locate and replace components causing excessive voltage drop.

Excessive current draw in the lift motor or traction motor.

1.

Under standard conditions, measure the pump motor current and the traction motor current and compare with the truck ratings. If high, check for:

A. Worn Brushes B. Partial motor winding C. Shorts to the truck frame. d.

e.

Significant changes in the way the truck is being used.

1.

Verify that the work cycle of the truck has not been changed significantly. The harder the truck is worked, the earlier lift lockout will be obtained.

2.

An example of a significant change is where a warehouse is being rearranged and inven-tory is being removed from one set of racks to another. This would involve an abnormal amount of lifting as compared to day-to-day operation, and the gauge would respond accordingly.

3.

If the new work cycle is permanent, see ADJUSTMENTS for how to proceed.

Loss of battery capacity.

1.

Sometimes overwatering the batteries will pre-vent them from being as fully charged as they were previously.

Instead of getting 1.285 (1285) specific gravity at full charge, 1.260 (1260) is obtained. This will result in a loss of useful capacity of 10% to 20%. For example, if the battery were being worked down to 1.175 (1175) SG, there would be 110 points of SG change when starting from 1.285 (1285), but only 85 points of SG when starting from 1.260 (1260).

Sheet 8: Battery Charging System 2. f.

If loss of capacity is suspected, contact Yale Service Engineering for guidance.

Defective fuel gauge.

When items 1 to 4 have checked out, replace the fuel gauge.

Figure 8-4—Battery Controller Wiring

ADJUSTMENTS Two potentiometers are available for adjustment. These adjust-ments should be made by authorized personnel under the circumstances described in adjustment procedures.

The RESET potentiometer determines the level to which the battery must be charged before the gauge will swing to "full. " It is factory set at B. Batteries with open circuit voltages greater than 2.09 volts per cell will cause the gauge needle to go to "full" (green ball position). 2.09 volts per cell corresponds approx-imately to 1.245 (1245) specific gravity.

Turning the RESET potentiometer from B towards E increases the voltage at which the battery is accepted (battery charged to higher specific gravity than 1.245).

Turning the RESET potentiometer from B towards A decreases the voltage at which the battery is accepted (battery charged to lower specific gravity than 1.245).

If the battery is not fully charged, the gauge will remain at its original position before the batteries were changed. For instance, if the truck was brought in with the gauge at lockout (needle next to red ball, red light blinking), and a different improperly charged battery is then installed, the needle will remain next to the red ball and the red light will continue to blink until a fully charged battery is installed.

All units are shipped from the factory set to full. No matter what the state-of-charge of the first battery the unit is connected to, the gauge will read full. Thereafter, the gauge will continue to read the state-of-charge of the last battery when used on the truck, if the replaced battery is not fully charged.

The DISCHARGE potentiometer determines the level at which lift lockout takes place. It Is factory set at N which corresponds to 1.73 volts per cell.

Going from N towards K will cause the battery to be more deeply discharged at lockout.

Going from N toward P will cause the battery to be less deeply discharged at lockout.

The following table give the NOMINAL voltage settings corres-ponding to the letter labeling of the DISCHARGE and RESET pots.

TABLE OF POT SETTING AND ASSOCIATED VOLTAGES PER CELL

Sheet 8: Battery Charging System

To find voltage settings for your battery, multiply volts per cell by number of cells. Example: 36 volt battery has 18 cells. N setting = 18 x 1.73 = 31.14.

WHAT THE GAUGE MEASURES In order to properly protect the battery and truck, the gauge must not only respond to how much energy is removed from the battery, but also the rate at which it is removed.

From standard battery discharge tests, it is well known that the higher the current, the smaller the number of ampere hours that can be removed from the battery before its voltage drops below an acceptable level. Low battery voltage causes contactors to chatter, causes motor starts to become sluggish and causes internal heating of the battery which shortens its life.

When the truck does heavy work consisting of a lot of lifting and little driving, the gauge will not permit as much total energy to be removed from the battery as when the truck does light work.

This will be evidenced in two ways: 1.

Lockout will occur sooner.

2.

The specific gravity of the battery at lockout will be higher.

Only when the occurrence of lockout interferes with the work schedule should adjustments be made. This should be done only after Yale Service Engineering has been contacted for guidance to ensure the equipment is not damaged and warranties invalidated.

Precise details of when to adjust and how to adjust are given in Adjustment Procedures.

ADJUSTMENT PROCEDURES Adjustments may be required for the following reasons and should be done only by authorized personnel.

1.

SYMPTOM: The truck comes in too soon for a battery charge.

If the battery is being charged, the reset potentiometer is set at B and the truck is being worked hard, the gauge will lock out at what appears to be earlier than normal. More time on the floor can be obtained by turning the discharge potentiometer towards K from N. Before making the adjustment, the specific gravity at the point where the meter light goes on should be checked Under no circumstances should the adjustment be made if the specific gravity corresponds to more than 80% discharge at the 6 hour rate, since the specific gravity (typically 1.140) can vary from 1.100 to 1.180 from cell type to cell type. Yale Service Engineering should be consulted in interpreting the reading obtained if needed.

2.

SYMPTOM: The specific gravity at lockout is very low.

This can occur with a lightly worked truck where there is very little lifting and a lot of travel. Most commonly, it happens with walkie pallet trucks.

Typically, the battery will be used for several shifts before being recharged. The discharge rate of the battery will be approximately 10 to 20 hours.

THIS CONDITION MUST BE CORRECTED Make a coarse adjustment by turning the discharge potentio-meter from N to P and measure the specific gravity after each of several cycles of operation.

Fine tune, if necessary, by turning back towards O if specific gravity is too high.

Sheet 3: Drive Unit

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

(See Figure 3-1.)

The drive unit gear box is mounted on a larger diameter ring bear-ing to provide easy steering. The ring bearing is adjustable to compensate for wear and to maintain the proper steering effort. All rotating parts of the drive unit are mounted on ball or roller bearings. Lubrication is provided by maintaining a specified level of 90 weight gear oil in the bottom of the drive unit.

Drive Motor Assembly The motor is mounted vertically on the top of the drive unit. The armature shaft extends out the top of the assembly to accommodate the top-mounted brake.

The motor is Yale-made with class H insulation, and sealed ball bearings. The motor is series-wound to provide high starting torque. A spiral bevel pinion gear is mounted to the armature shaft, which extends into the upper housing. For removal of the drive motor, see below.

Upper Housing The upper housing of the unit supports the drive motor and contains the spiral bevel ring, which mates with the motor pinion.

The shaft on which the ring gear is mounted has spur gear teeth machined on one end to transfer motion down to the lower housing gears.

Lower Housing The lower housing contains the idler gear, which meshes with the cross shaft in the upper housing. The idler gear transfers the motion to the 2nd reduction gear, which is keyed to the drive wheel shaft. An inspection cover on the side of the lower housing contains a drain plug, and a plug in the center, to check the drive unit oil level. A machined surface around the center of the lower housing provides the mounting for the inner race of the ring bearing.

REMOVE AND REPLACE DRIVE MOTOR Remove 1.

Disconnect the battery.

2.

Remove the compartment cover to expose the drive unit.

3.

Tag and disconnect motor wires and harness clamps on motor.

4.

Remove four screws that hold the motor to the drive unit.

5.

Lift motor off drive unit. (See Figure 3-2.)

Sheet 3: Drive Unit

Figure 3-1 Drive Unit

Figure 3-2 Motor Removal

Sheet 3: Drive Unit

Figure 3-3 Drive Unit Assembly ITEM DESCRIPTION 1. Drive motor assembly 2. Hex screw 3/8-16 3. Lock washer 3/8 4. Breather 5. Gasket 6. Shim (select) 7. Bevel gear and pinion 8. Shim for bevel gear 9. Ball bearing 10. Shim .005 11. Bearing retainer 12. Hex screw 13. Washer 14. Castle nut 5/8-18 15. Cotter pin -1/8x1" Ig. 16. Hex nut 17. Hex screw 1/2-13x2" Ig. gd.5 Hex screw 1/2-13x2-3/41g. gd.5 Socket hd. screw 18. Lockwasher 1/2" 19. Upper housing 20. Set screw 21. Hex bolt 5/8-18x4" Ig. 22. Shield 23. Outer race 24. Inner race

Sheet 3: Drive Unit 25. Steel ball 26. Tire & wheel assembly 27. Clamp plate 28. Hardened washer 29. Wheel bolt 30. Dowel pin 31. Gasket 32. Drive axle shaft 33. Oil seal 34. Roller bearings 35. Lower housing 36. Ball bearing 37. Retaining ring 38. Shim .003 39. 2nd reduction gear 40. Cotter pin 1/8x3" Ig. 41. Key 42. Nut 43. Hex screw 3/8-16x1-1/8 44. Magnetic pipe plug 45. Pipe plug 1/4 46. Cover 47. Gasket 48. Idler gear shaft 49. O ring 50. Retaining ring 51. Ball bearing 52. Idler gear 53. Spacer 54. Dowel pin 1/4" dia. x 5/8" lg.

Dowel pin 1/4" dia. x 7/8" lg.

55. Hex nut 5/8-18 56. Lube fitting 57. Expansion plug 58. Ball bearing 59. Upper housing cross-shaft 60. Key—for bevel gear 61. "O" ring 6.

Remove shims (6), pinion (7), and lock nut (16) from armature shaft. (See Figure 3-3)

7.

Inspect components for damage and replace as necessary.

8.

Remove old gasket (5) from housing and discard.

Replace 9.

Install shims (6), pinion (7), and lock nut (16) on the armature shaft.

10. Install a new gasket (5) on the housing.

11. Place motor on drive unit.

12. Install screws (2) and lockwashers (3). Tighten screws evenly.

REMOVE AND REPLACE DRIVE UNIT Remove 1.

Raise and block front of the truck approximately 12 inches off the floor.

2.

Attach a sling and overhead hoist to the drive unit.

3.

Remove the four bolts and locknuts from the ring bearing.

Sheet 3: Drive Unit 4.

Lower drive unit to the floor, remove sling, and roll out from under truck.

Replace 5.

To replace the drive unit reverse steps 1-4.

NOTE: When replacing the drive unit do not tighten the ring bear-ing mounting bolts until final adjustment of the ring bearing is made. See adjustment procedure.

REMOVE AND REPLACE THE DRIVE WHEEL REFER TO FIGURE 3-3 Remove 1.

Loosen and remove the five wheel bolts (29) and washers (28) securing the wheel (26) to the drive axle shaft.

2.

Remove clamp plate (27) from wheel hub.

3.

Remove wheel.

Replace 4.

Mount the wheel on the drive axle shaft.

5.

Replace the clamp plate.

6.

Replace and tighten wheel bolts with their washers.

7.

Torque wheel bolts to 140-160 ft. Ibs.

DISASSEMBLE AND ASSEMBLE THE DRIVE UNIT REFER TO FIGURE 3-3 Disassemble 1.

Remove brake assembly.

2.

Remove the drive motor (see appropriate procedure).

3.

Remove the drive unit from the truck (see appropriate procedure).

4.

Remove the drive wheel (see appropriate procedure).

5.

Move drive unit to a clean work area.

WARNING: The drive unit could contain asbestos dust from the brake linings. If using compressed air for cleaning, always wear a mask.

6.

Before disassembling drive unit, wash and thoroughly clean the outside of the drive unit. Do not allow cleaning fluid to get in the drive motor or on the brake linings. Blow dry with an air hose when compressed air is available. Place drive unit on a bench or stand, and securely block in an upright position. Remove drain plug (44) and drain oil in a pan if not already done. Replace plug.

7.

To remove the upper housing (19):

8.

a.

Remove four screws (17) and lockwashers (18) secur-ing upper (19) and lower (35) housings.

b.

Separate and remove the upper housing from the lower housing (35).

To remove the upper housing cross shaft: a.

Remove cotter pin (15), nut (14).

b.

Remove four screws (12), lockwashers (3), bearing retainer (11) and shim (10).

c.

Using a plastic hammer, tap threaded end of cross shaft (59) out opposite end far enough to remove expansion plug

Sheet 3: Drive Unit (57), bearing (9), shims (8) and gear (7). d.

9.

Remove key (60), shaft (59), bearing (58) and "O" Ring (61).

To remove idler (intermediate) gear assembly a.

Remove dowel pins (30 and 54).

b.

Insert, /2"-20 bolt into idler gear shaft (48) to pull shaft. A slide hammer will make this task easier.

c.

Remove idler gear shaft (48), idler gear (52) and spacer (53).

d.

Remove and discard "O" ring (49).

e.

Remove one retaining ring (50) and bearing (51) from idler gear (52).

10. To remove axle shaft assembly from the lower housing (See Figure 3-4): a.

Remove four screws (43) and lockwashers (3) securing cover (46) to lower housing (35). Remove cover (46) and gasket (47).

b.

Remove five bolts (29) and washers (28). Remove clamp plate (27) and wheel (26).

c.

Remove cotter pin (40) and nut (42) from axle shaft (32).

d.

Using a brass bar tap axle shaft (32) out of drive gear(39) and bearings (34 & 36). Remove shaft (32).

e.

Remove drive gear (36) and key (41).

f.

Remove shim (38), retaining ring (37) and inner bear-ing (36)

g.

Remove oil seal (33) and outer bearing (34).

Figure 3-4 11. To remove the ring bearing assembly from the lower housing: a.

Remove the bearing shield (22).

b.

Remove lock nut (55) and hex bolt (21) from outer bearing block race (23). See Figure 3-5.

Sheet 3: Drive Unit

Figure 3-5 c.

Turn adjusting screw (20) in to spread outer race. Rotate race to let balls drop out of the opening (See Figures 3-6 and 3-7).

Figure 3-6 d.

When all ball bearings are removed from the assembly the outer race (23) will lift off.

Figure 3-7 e.

Spread inner race (24) at joint and work off drive unit assembly (See Figure 3-8).

Sheet 3: Drive Unit

Figure 3-8 Assemble the Drive Unit Refer to Figure 3-3 1.

Before reassembling the drive unit assembly, wash and thoroughly clean all parts in a suitable solvent and dry. Make sure that all gasket material has been removed from the hous-ings 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 block threaded holes for damage.

3.

Check all bearings for excess wear and flat spots. Dip clean bearings in new clean drive unit oil and wrap in a clean lint-free cloth until ready to use.

4.

Check all gears for excess wear, damaged teeth and keyways. Check keys for rounded edges and cracks.

5.

Check all shafts for excess wear and damaged keyways. Check keys for rounded edges and cracks. Check key fit in the proper shaft keyway and if fit is loose, replace key and/or shaft.

6.

Replace all worn or damaged parts. When reassembling use new gaskets, "O" rings, and oil seals. A kit is available that contains all of the gaskets, seals, "O" rings, bearings and other normally replaceable items.

7.

Mount and assemble the ring bearing assembly on the lower housing:

8.

a.

Install inner race (24) on lower housing (35).

b.

Install outer race (23) around inner race and spread just enough to insert the bearing balls (25) between the races. Be sure that 72 balls are installed.

c.

Install bolt (21) and locknut (55) in outer race. Do not overtighten. Adjust set screw (20) to maintain approxi-mately 1/8" gap in ring bearing race.

d.

Final adjustment of the ring bearing cannot be made until the drive unit is mounted in the truck frame.

Install the axle shaft in the lower housing: a.

Install the outer bearing (34) and new oil seal (33) in lower housing bearing bore. Apply a light coat of clean oil to the l. D. of the oil seal.

b.

Install inner bearing (36) and retaining ring (37) with shim (38) to reservoir side of housing.

c.

Insert key (41) in drive gear (39). Position drive gear in housing.

d.

Carefully insert axle (32) through oil seal (33), outer bearing (34), and inner bearing (36). Align keyway in shaft with key and tap axle in place.

e.

Install and tighten nut (42), lining up a slot in the nut with a cotter pin hole in the shaft. Install a new cotter pin (40) and spread. If cotter pin hole in nut does not line up, add or subtract shim (38), as required to tighten screw.

f.

Using a new gasket (47), install cover (40) on lower housing using screws (43) and lockwashers (3).

g.

Mount wheel (26), on axle (32) and secure in place with clamp plate (27), washers (28) and bolts (29). Torque bolts to 140-160 ft. Ibs. dry.

Sheet 3: Drive Unit 9.

Install Idler (Intermediate) Gear: a.

Apply a light coating of grease to a new "O" ring (49) and install on shaft (48).

b.

Install bearing (51) in idler gear (52). Install retaining ring (50) in gear.

c.

Position spacer (53) and gear (52) in housing (35), insert and tap shaft (48) in place. Turn shaft to align dowel pins holes, install both dowel pins (30) and (54) in housing (35) to secure shaft (See Figure 3-9).

Figure 3-9 10. Install upper housing cross shaft and spiral bevel gear:

Figure 3-10 a.

Apply a light coating of Vaseline to a new "O" ring (61) and install in groove on shaft (59).

b.

Install bearing (58) on pinion end of shaft (59). Shield on bearing should face inward to centerline of drive unit.

c.

Insert key (60) in shaft (59).

d.

Position the spiral bevel gear (7) in the upper housing. Insert cross shaft (59) through the block bearing bore and gear.

Align key with keyway machined in the gear (See Figure 3-10).

e.

Tap bearing (58) into the housing. Ensure that the gear (7) is snug against the shaft shoulder. Pinion on the shaft should be snug against the bearing shield (58).

f.

Install shims (8) and ball bearing (9). Use enough shims to prevent lateral movement of the ring gear, but not too many to prevent the bearing retainer from fitting flush on the housing.

g.

Install bearing retainer (11) using four screws (12) and lockwashers (3).

h.

Install washer (13), castle nut (14) and cotter pin (15).

i.

Install a new expansion plug (57) in housing bearing bore.

j.

Put a 1/8" bead of silicon sealer around the outer edge of the expansion plug (57), Welch plug and tap into place.

Sheet 3: Drive Unit 11. Install upper housing: a.

Install a new gasket (31) on the lower housing.

b.

Insert dowel pin (54) in lower housing (See Figure 3-11).

Figure 3-11 c.

Position upper housing over lower housing. Be certain dowel pin holes are properly aligned.

d.

Install screws and lockwashers (17 and 18), tighten screws (See Figure 3-12).

e.

Check that drain plug (44) is in place and tight.

f.

Remove oil level plug (45) if it has not been removed.

g.

Remove breather plug (4) from upper housing. Consult Lubrication Section and add oil through filler hole until it starts to flow from oil level hole. Install and tighten both oil level and breather plugs.

h.

Spin drive wheel by hand to make sure that all gears and bearings rotate freely.

Figure 3-12 12. Install the drive unit on the truck frame (see appropriate procedure).

13. Adjust the ring bearing (see appropriate procedure).

14. Adjust pinion and spiral bevel gears (see appropriate procedure).

15. Mount the drive motor on the upper housing (see appropriate procedure).

RING BEARING ADJUSTMENT

Sheet 3: Drive Unit Proper adjustment of the ring bearing will assure the following: Easy steering effort.

Minimal deflection (side play) of the entire drive unit and motor assembly.

Long bearing life.

Adjustment is made by turning the set screw (20) in the outer bearing race in or out to tighten or loosen the outer race against the ball bearings. Adjusting the outer race too tightly will cause increased steering effort and abnormal wear of the entire ring bearing assembly. A loose adjustment will also cause abnormal wear of the ring bearing, in addition to objectionable deflection and looseness of the entire drive unit within the bearing assembly.

Another consideration that must be kept in mind when making these adjustments is the possibility that the frame platform to which the ring bearing is mounted may be slightly warped. A warped frame will cause stress on the ring bearing and will increase steering effort. Carefully follow the steps outlined in the following procedure.

Figure 3-13 Ring Bearing Adjustment Procedure 1.

First disconnect the battery, then grease ring bearing with a multi-purpose grease. The bearing race should be heavily greased at all times to prevent contamination of the race-way.

2.

Deflection of the drive unit should be measured with no load on the forks. Impose a horizontal force of 45-55 Ibs. The radial deflection of the drive unit must not exceed a total of .090" (.045" in any direction) measured at the top of the drive motor commutator end head. If the deflection is within specifications, skip Steps 3 and 4 and proceed to Step 5. If excessive deflection is determined, proceed to Step 3.

3.

If steering is found to be loose or have excessive play, loosen the four ring bearing mounting bolts and loosen ring bear-ing clamp screw and nut. Turn the set screw counter clockwise until play is removed. Tighten as described below.

4.

Draw the outer bearing race against the truck frame plate by snugging up 3 of 4 ring bearing mounting bolts to seat the race firmly without imposing any distortion into it. Measure the gap at the 4th bolt. If the gap is more than .025, shimming is required together with the standard spacer at that hole. (See table below for shimming guidelines.) Install the required shim(s) and tighten the 4 ring bearing mounting bolts to 75 ft. Ibs. torque.

GUIDELINE FOR SHIMMING DRIVE UNIT OUTER RACE Shim(s) Total Shimpack Gap Req'd Thickness 0"-.025 None 0" .026"-.030" 1-.020" .020" .031"-.050" 2-..020" .040" .051"-..070" 3-.020" .060" .071"-..090" 4-.020" .080" .091"-.110" 5-.020" .100" Check the steering again and repeat the following steps as required.

5.

If steering is found to be too tight, loosen four ring bearing mounting bolts, loosen ring bearing clamp screw and nut. Turn

Sheet 3: Drive Unit set screw clockwise until steering effort is made easier without exceeding the specified deflection limits. Tighten the four ring bearing mounting screws (75 ft. /lbs. torque) before tightening clamp screw. To prevent distortion of the outer race, do not tighten clamp screw excessively.

6.

Recheck the steering effort. Binding indicates that the shim-ming procedure may have to be redone, especially if the steering effort is easier when the four mounting bolts are loosened.

Ring Gear and Pinion Adjustment 1.

Assemble the drive unit (see appropriate procedure).

2.

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

3.

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 shims that must be used.

Example: #1 Old Dimension 1.698" New Dimension 1.693" difference .055" In this example you must use the old shim pack plus an additional .005" shim. #2 Old Dimension 1.698" New Dimension 1.703" difference .005" In this example you must use the old shim pack less a.005" shim.

4.

Check that proper number and dimension of shims have been installed.

5.

Adjust tooth contact. a.

Lightly apply marking compound to eight or nine spiral gear teeth.

b.

Position shims and install motor with socket head screws (see motor installation procedure). Original shims have already been installed between housing cover and retainer.

c.

Apply a small amount of resistance to drive wheel and rotate armature with a wrench. In rotating the gears the marking compound will be squeezed away from the areas of tooth contact. When making adjustments check both sides of the gear teeth. Remove or add shims at motor and retainer as necessary to obtain correct tooth contact. Correct tooth contact will also give proper backlash of .003 to .005 inches.

d.

Note the nature of tooth contact as shown in Figures 3-14 to 3-18. Make necessary adjustments to obtain cor-rect tooth contact as shown in Figure 3-14.

Figure 3-14 indicates proper contact.

Figure 3-15 indicates a high narrow contact. Remove a shim at motor and add one at retainer.

Figure 3-16 indicates a low narrow contact. Add a shim at motor and remove one at retainer.

Figure 3-17 indicates a short toe contact. Remove a shim at motor and add a shim at retainer.

Figure 3-18 indicates a short heel contact. Add a shim at motor and remove one at retainer.

e.

Install shims, motor, lockwasher and socket head screws. Be certain drive unit has been filled with SAE 90 gear oil to proper level (drive unit capacity is approx-imately 1 qt.) after above adjustments have been made.

GEAR ADJUSTMENT (When Original Gears are Reinstalled) Gears that have been in service for long periods form running contacts, therefore gear lash can only be reduced to a point of

Sheet 3: Drive Unit smooth rotation of gears.

1.

Position original shims and install motor with socket head screws. Original shims have already been installed between housing cover and retainer.

2.

Turn armature to check backlash. Smoothness or roughness may be felt by rotating armature. If a slight overlap takes place, rotation will be rough and an additional shim will be necessary at retainer.

3.

Be certain drive unit has been filled with SAE 90EP GEAR OIL to proper level.

TOOTH CONTACT DIAGRAMS

Figure 3-14—Correct Contact

Figure 3-15—High Narrow Contact

Sheet 3: Drive Unit Figure 3-16—Low Narrow Contact

Figure 3-17—Short Toe Contact

Figure 3-18—Short Heel Contact

Sheet 2: Electrical System

ELECTRICAL SYSTEM CABLEFORM SCR—SUPER PC-8 CONTROL UNIT INTRODUCTION The PC-8 ("Pulsomatic") control is different from those used in other Yale trucks in that it incorporates a 1A bypass contactor for full speed operation. The most common application of the ESC truck is narrow aisle warehouse work that requires long runs in top speed. Using a 1 A bypass contactor eliminates the neces-sity of operating for long periods of time with the 1 REC in full conduction. This will prevent the SCR panel from overheating and will allow the truck to travel slightly faster.

The fault detector in the Super PC-8 control is also unique in that it has a look-ahead feature to prevent truck operation if the 1 REC is shorted or the 1A contactor is welded.

GENERAL DESCRIPTION—CONTROL UNIT The Super PC-8 Control Unit provides logic (timing and control) and SCR (high current switching) components in a single com-pact assembly. It is designed for use in controlling the effective voltage applied to, and therefore the speed and torque of, the series-wound drive motor of a battery powered electric forklift truck. Circuitry is provided for the protection of both motor and controller from excessive current, over-temperature (180°/184°F), reversed or discharged battery, and component failure.

Circuitry for control of a by-pass contactor is also provided. Controlled plug braking (plugging) is standard.

CIRCUIT DESCRIPTIONS Refer to the wiring diagram on Page 2-24, and to Figure 2-1 when reading the following circuit descriptions. Figure 2-1 is a partial schematic that shows only the SCR panel components and the control switches. This diagram helps to understand the intercon-nections between the two pin connector strips that are located on the logic card. The 14-pin connector is wired into all of the control switches and the accelerator pot. The 17-pin connector is wired to all of the components on the SCR panel.

Figure 2-1 control circuit does not show the drive motor and contactor cir-cuit, which would be connected to the SW terminal.

The truck wiring diagram on Page 2-24 of this chapter shows these two pin connectors at the top and bottom of the Control Card, with the 17-pin connector at the top designated as 2-1 through 2-17, and the 14-pin connector shown as 1-1 through 1-12 at the bottom.

SPEED CONTROL CIRCUITS Speed control is accomplished mainly by the accelerator potentio-meter. The pot is connected to the logic card pins 1-8, 1-9 and 1-10 via wires 16, 14, and 15. As the accelerator handle is rotated to the full speed position in forward or reverse, the resistance between 1-8 and 1-9 increases from zero to five hundred ohms. As the pot resistance increases, the oscillator output voltage to the 1REC (TH1) from pin 2-17 increases from zero to 1.5 volts to provide a faster pulse rate of the SCR. At the same time, the gate voltage to the 2REC from pin 2-15 decreases from approx-imately 1.5 volts to zero. Voltage to the pot is supplied by the 12-volt regulator circuit through pin 1-10. The voltage is further reduced by a 560 ohm resistor located near the pot. As the ac-celerator pot is rotated, the voltage at pin 1-9 increases from 0 to 5.5 volts.

Another factor that controls the truck's speed is the thermistor (TM1 —see Figures 2-1 and 2-4). The thermistor is a heatsensitive resistor whose resistance increases with the rise in temperature. It is mounted on the heat sink near the 1 REC where it can monitor the temperature of the SCR. If the operating temperature of the 1 REC gets too high, the thermistor reduces the number of pulses out of the oscillator. This will reduce the number of times the 1REC turns on until it cools to a safe operating temperature. The thermistor is in the control circuit only to prevent damage to the 1 REC. Its effect will be noticed any time the duty cycle of the truck operation is demanding enough to cause a damaging heat rise in the 1 REC. The thermistor serves to override the accelerator pot's control on truck speed when the 1REC overheats. Thermal cut-out will begin at 180°to 184°F, with full cut-out at 192°/194°F. POWER CIRCUIT In Figure 2-3 (ESC Drive Control Assembly), the flyback diode is labeled D4 and the plugging diode is labeled D3. The SCR circuit is also similar except for the 1A bypass contactor that is closed when the truck reaches 80 to 90% full speed. When the 1A contactor is closed, the entire SCR circuit is circumvented and full battery voltage can flow through the drive motor.

VOLTAGE REGULATION CIRCUIT Most of the logic card circuits operate on a regulated 1 2-volt supp-ly. This circuit is energized as soon as the key switch is

Sheet 2: Electrical System turned on. Positive battery current flows from the key switch via wire 4, through a 5 amp fuse and then to logic card terminal 1-11. From terminal 1-11 current flows through the logic card to ter-minal 2-4, through a 33-ohm resistor (R1), and then through a 12-volt zone diode (D1) to negative. Since the positive track of the logic card is connected in parallel to the zener diode by pin connection 2-5, the logic card will also operate on 12 volts. The voltage regulator circuit can be easily tested by checking for 12 volts + 1 volt at card terminals 2-5 or 1-10.

Special Equipment For Servicing This Control: a.

Volt-Ohm Meter (Part No. 5180968-30.)

b.

Force Gauge (SCR Units) (Part No. 5183538-48.)

c.

Yale Component Tester (SCR Units) (Part No. 5180968-31).

Sheet 2: Electrical System

Figure 2-1—Super PC-8 Control Circuit DIRECTIONAL COIL CIRCUIT The forward and reverse directional coils are connected to bat-tery positive as soon as the key switch is closed. The negative sides of the coils are connected by the forward and reverse direc-tional switches to the parking and service brake switches and then to logic card terminal 1-3. Current flows through the logic card and then from pin 2-10 to the small 3.15 amp fuse (FS1) located on the panel. The fuse is connected back to the logic card pin 2-9 and the fault detector relay RLA which is closed as

Sheet 2: Electrical System soon as the key switch is closed. From the relay, current flows to pin connector 2-1 and then to the battery negative. This com-pletes the directional coil circuit. The selected coil will now energize to magnetically close the motor contactor. When the forward direction has been selected, the logic card voltage at pin 1-7 becomes negative so that the logic card can begin oscillating to supply a gate signal for the 1 REC (TH1). When the reverse directional coil is energized, pin 1-6 of the logic card becomes negative to begin pulsing of the SCR. Current limit control is a third factor that controls the speed of the truck. The logic card monitors current draw through the SCR panel by wires 6 and 9, which are connected to the shunt. If the current demand rises above 300 amps + 10 amps, the logic card reduces the pulse rate of the 1REC to limit the maximum cur-rent draw to 300 amps. When the truck is in the 1 A mode of opera-tion, the logic card is no longer able to control motor current— so a 300 amp power fuse (FU-1) is used to provide motor protection.

When the truck is in the plugging mode, the logic card senses the current that is generated in the armature and D3 REC loop by wire 10, which is connected to pin 1-1. During normal truck operation, the voltage at pin 1-1 is negative, but during plugging the voltage becomes positive due to the generated voltage. The logic card then reduces the oscillator output to bring the truck to a smooth stop.

Figure 2-2—Accelerator Assembly

Sheet 2: Electrical System

Figure 2-3— ESC Drive Control Assembly

Figure 2-4— Super PC-8 SCR Panel 1A BYPASS OPERATION The 1A bypass circuit provides full speed operation by closing the 1A contactor to shunt the motor current around the SCR control. The circuit is initiated by rotating the accelerator to either extreme position to close the MS-2 switch. When MS-2 is closed, a timer circuit inside the logic card activates—and after a 2 second delay, it allows pin 1-2 to be connected to negative.

Positive current can now flow through the 1A coil to pin 1-2 via wire 23 and then to battery negative to energize the coil and close the 1A contactor. The two second time delay prevents the operator from travailing immediately in full speed by rapidly turning the accelerator handle to close the MS-2 switch. The truck will gradually build up speed for 2 seconds before the 1A contactor closes.

FAULT DETECTOR CIRCUIT The fault detector circuit and relay is contained within the logic card. The relay (RLA) will close with an audible clicking sound whenever the key switch is closed. However, to make sure that the relay contacts are making a good electrical connection, check for continuity between pins 2-9 and 2-1 when the key switch is closed.

Among Pulsomatic controls, the fault detector circuit in the Super PC-8 control is unique in that it has the ability to "look ahead" to determine if certain faults exist in the truck. These faults would be a shorted 1 REC or a welded 1 A contactor. If either of these faults is present the relay (RLA) will not close, which in turn will prevent the directional coils from energizing.

Sheet 2: Electrical System The look ahead" feature prevents the truck from momentarily lurching until the contactor trips if either of these faults occurs.

If there is a fault in the turn-off circuit, the truck will momentarily close the contactors and then the fault relay will open. The turn-off circuit is responsible for shutting off the 1 REC once it has turned on. This circuit consists of the 2REC, capacitor, choke coil, commutating diode and the oscillator section of the card that turns the 2REC on. If any of these components malfunction, the 1 REC will turn on and stay on; however, the fault detector will sense that the 1REC is not pulsing and it will open the fault relay.

Proper functioning of the fault detector circuit can be easily checked by operating the truck in the SCR range with the drive wheel jacked off the floor. Then manually push the 1 A contactor closed. The fault relay should immediately trip out the directional contactor. Also manually close the 1 A contactor and try to operate the truck. The directional contactors should not close. If the commutating diode (D1) lead is removed from the choke coil and the truck is operated, the directional contactor should momentarily close and then immediately open. If any of these tests fail, the logic card should be replaced.

Because of the "look ahead" feature, any "open" in the motor circuit from the SW power connection to the positive armature connection (A5) will also cause the fault detector to trip out when the accelerator pot is rotated. Lack of motor continuity is sens-ed through the SW lead connection to the logic card.

CAUTION: Disconnect the batteries and discharge capacitor(s), using insulated tool, and jack drive wheel off floor before making any adjustments or servicing replacement parts. Only qualified service personnel should work on these electrical systems.

HELPFUL HINTS TO REMEMBER WHILE MAINTAINING OR TROUBLESHOOTING ELECTRICAL CIRCUITS. 1.

Disconnect battery when troubleshooting, or checking cir-cuits with another source of power.

2.

Disconnect or isolate wires when checking continuity of circuits.

3.

Exercise caution when tightening wire connections. Make sure they are torqued properly.

4.

Exercise caution when tightening motor leads, to prevent turning of the stud—this will distort or break internal motor connections.

5.

Prevent oil from getting into the motor when working on hydraulic components.

6.

Periodically blow out drive and pump motors. Make sure no moisture or condensation is in the compressed air.

7.

Check all mechanical parts of contacts. Check the spring for discoloration and loss of tension, the armature pivot points, over-travel of armature and the contactor pigtail.

8.

Remove all dirt and debris before removing the drive motor.

9.

Mark or tag all wire leads prior to motor removal. This will prevent mistakes on rewiring.

10. Cover all open gear cases after motor removal to prevent foreign matter from falling into gear train.

11. Always use a wiring diagram and/or schematic when troubleshooting. These will prevent many hours of needless trial-and-error work.

12. Take extra caution when installing new brushes, making sure they are properly seated (refer to Preparation of Commutator) and all pigtails are connected without grounding against steel components. Brushes should move freely in brush holders.

Brush springs should have the proper tension: 30 oz. for pump motor, 38 oz. for drive motor.

13. Check the specific gravity of the battery using a hydrometer, making sure it does not read below 1.150. A fully charged battery should read 1.275.

WARNING: When truck is EE spark enclosed, make sure covers have been replaced before putting truck into operation.

Sheet 2: Electrical System CONTACTORS—GENERAL The contactors used on the ESC truck are designed by Cableform for low voltage, intermittent duty operation. The two types used are: 1. Single pole, double throw type (one normally open and one normally closed contact), used for the directional contactors.

2. Single pole, single throw type (one normally open contact), used for the 1A Bypass, the pump, and the power steering contactors.

All these contactors are located on the control panel.

CONTACT TIP MAINTENANCE The most common maintenance required for contactors is contact tip replacement.

Periodic inspection of the contact tips is important. If they show excessive wear or pitting, they should be replaced. Lift truck contactors are designed to have replaceable tips.

Excessive pitting and burning of contact tips makes them prone to welding. The silver in the contact tips contains cadmium oxide to reduce the susceptibility to welding.

1A CONTACTOR DISASSEMBLY 1. Using a 10mm wrench, loosen and remove nuts and lock washers from connection bolts.

2. Remove stationary contact (1 ) and tubular spacer (2) from front molding (3). (The spacer fits around the bolt and is located in the body of the molding.) Using thumb and forefinger, squeeze lower part of front molding to disengage from magnet frame (5). Lift contactor assembly upwards in a rotating movement to remove from base plate molding (4).

3. Depress top spring stud (9) and rotate 90°to disengage from slot in underside of armature plate. Remove stud and spring.

4. Remove free end of braid (6) from rear connection bolt. Using thumb and forefinger, squeeze armature plate re-tainer (8) to release its fixing feet from slots in armature (11 ) and remove moving contact (10) and braid assembly. Remove (with a 7mm wrench) the nut retaining braid onto moving contact.

5. Lift off armature plate and compression spring (7) from center of coil pole piece (12).

6. Coil (13) can now be removed using a 1 Omm wrench on bolt underneath magnet frame.

Sheet 2: Electrical System Figure 2-5—1A Contactor 1. Stationary Contact 2. Tubular Spacer 3. Front Molding 4. Base Plate 5. Magnet Frame 6. Braid Assembly 7. Compression Spring 8. Armature Plate Retainer 9. Stud 10. Moving Contact Assembly 11. Armature Plate 12. Pole Piece 13. Coil Assembly 14. Resistor Diode—24-Volt Contactors 1A CONTACTOR REASSEMBLY 1.

Place rear connection bolt in position in the magnet frame. Fix coil to magnet frame using the 10mm bolt, ensuring that coil connections are facing to front or rear of contactor as required, and snap frame into base plate.

2.

Place one compression spring in the recess in the center pole-piece.

3.

Place armature plate (11) with curved edge forwards and upwards so that compression spring sits in recess underarmature plate, and straight rear edge of plate sits on ledge and under two protrusions on the magnet frame.

4.

Take moving contact (10) and braid assembly holding it with thumb and forefinger at either side of armature plate retainer (8).

5.

Squeeze sides of retainer to allow feet to enter slots in top of armature plate while ensuring that rear protrusions of arm-ature plate retainer are behind magnet frame. Braid can now be placed onto rear connection bolt. Check that feet of ar-mature plate retainer have "clicked" home into position under armature plate.

6.

Place bolt into front molding. Front molding can now be slipped into place on the front of magnet frame, at the same time ensuring that front of moving contact (10) is inside molding.

7.

Fit second compression spring onto top spring stud (12) and slide hammer-shaped end into slot in moving contact and through armature plate. Press and lock with a 90°turn.

8.

Place rear slots in magnet frame under base molding, squeeze front molding to allow assembly to drop down and lock onto base molding.

9.

Replace tubular spacer flange outwards, by sliding onto front connection bolt and into body of molding.

10. Replace stationary contact onto front connection bolt, press-ing contact into recess in front molding, thereby locking molding in position.

11. Replace locking washers and nuts onto connection bolts.

12. Check to ensure that the armature plate is correctly located at hinge end, and that it and the moving contact move freely without binding.

Sheet 2: Electrical System

Figure 2-6—DIRECTIONAL CONTACTOR ITEM

DESCRIPTION

1. Bus Bar 2. Stationary Contact 3. Tubular Spacer 4. Front Molding 5. Base Plate 6. Magnet Frame 7. Braid Assembly 8. Compression Spring 9. Armature Plate Retainer 10. Rear Molding 11. Back Contact 12. Stud 13. Moving Contact Assembly 14. Armature 15. Pole Piece 16. Coil Assembly 17. Resistor Diode—For 24-Volt Contactors DIRECTIONAL CONTACTOR DISASSEMBLY (See figure 2-6) The procedure is the same as the 1A contactor steps 1 through 3 Then take the following additional step: 3a. From rear of contactor, push top (stationary) contact forward in top molding as far as it will travel. With thumb and forefinger, squeeze rear of top molding to disengage from magnet frame and lift clear.

Now proceed with steps 4 through 6 described for 1A contactor.

DIRECTIONAL CONTACTOR REASSEMBLY 6a. Holding two halves of the top molding between thumb and forefinger, slide top (stationary) contact just into slots on inside edge of molding. Engage vertical slots in rear molding inside raised rear horns of magnet frame and slide molding down into position. Slide top (stationary) contact rearwards in slots in molding, at same time depress moving contact to allow silver tips to mate. Rear molding is now locked into position.

Now proceed with steps 7 through 12 of procedure described for 1A contactor.

COMPONENT TEST PROCEDURES (See Page 2-24) Following are test specifications and procedures for checking all of the drive control related components on the ESC. Many components can be checked without removing any leads other than the logic card pin connector plugs. Some components must

Sheet 2: Electrical System have several leads removed and the proper indications will be given for those components. If a component checks bad, isolate the component completely and recheck it since another component in parallel to it could be bad. All components can be checked with a simple volt-ohm meter.

1REC (TH1) Remove 17-pin connector from card.

Remove 10 amp bayont fuse (FU2) located adjusted to key switch.

Remove uppermost capacitor (C1) lead.

Connect positive meter lead to the SW terminal and negative meter lead on the shunt With meter on the R X 10, 000 scale, reading should be more than 100, 000 ohms.

Reverse meter leads from previous step and reading should also be more than 100,00 ohms.

Connect meter on R X 1 scale with negative meter lead on the shunt and positive meter lead pin 2-17.

on

Reading should be between 10 and 80 ohms.

Reverse meter leads from previous step and reading should be more than 5 ohms.

Check for continuity between the shunt and pin 2-16, which is the auxiliary cathode.

2REC (TH2) Remove 1 7-pin connector from card.

Remove uppermost capacitor lead..

Connect positive meter lead to the 2REC pigtail that was removed from the capacitor and negative meter lead to the shunt.

With meter on the RX 10,000 scale, reading should be more than 100,000 ohms.

Reverse meter leads from previous step and reading should also be more than 100, 000 ohms.

Connect negative meter lead to shunt and positive meter lead to pin 2-15.

Meter reading should be between 10 and 80 ohms on the R X 1 scale.

Reverse leads in previous step and reading should be more than 5 ohms.

Check for continuity between the shunt and pin 2-13 to check the auxiliary cathode.

Diodes (D1-D5) and Zener Diode (ZD1) STEP 1 With meter on R X 1, positive meter lead on anode and negative meter lead on cathode, meter reading should be 5 to 25 ohms.

STEP 2 Reverse leads from step 1, and meter reading should be more than 10, 000 ohms on the R X 10, 000 scale.

NOTE 1 The commutating diode D1 and the flyback diode D4 can be checked without removing any leads.

Sheet 2: Electrical System NOTE 2 The plugging diode D3 must have the pigtail disconnected before checking.

NOTE 3 Diode D5 is a combination block of three diodes to operate the hour meter when either of the directional coils or the hydraulic coils are energized. The positive meter lead should be left on terminal wire 27 with the negative lead moved to wires 11, 7, and 28a to check step 1 procedure.

For step 2 of the pro-cedure, connect negative meter lead to wire 27 and move the positive lead to the other three terminals. Disconnect at least three leads from the module before checking.

NOTE 4 ZD1—Connect positive meter lead to the stud end of ZD1 and negative lead to pin 2-5. Then check as outlined in steps 1 and 2.

Capacitor (C1) Remove 17-pin connector from card.

Connect meter on R X 10, 000 scale to capacitor terminals. Meter needle should swing towards zero then increase gradually to above 100, 000 ohms.

Reverse meter leads, and meter should repeat the charging action.

Choke Coil (L1) Meter reading should be close to zero ohms on the R X 1 scale.

Thermistor (TM1) Connect meter on R X 1 scale to pin 2-11 and 2-14 with 17-pin connector removed from card.

Reading should be approximately 100 ohms at room temperature. Cut-out begins at 180°/184°F. Accelerator Pot Remove 14-pin connector.

Connect meter on R X 100 scale to pins 1-8 and 1-9.

Meter reading should increase from 0 to 500 ohms as accelerator pot is rotated in both the forward and reverse directions.

Connect meter from pins 1-9 to 1-10.

Meter reading should decrease from 1000 to 500 ohms as accelerator is actuated.

The accelerator pot can also be checked by testing for voltage at pin 1-9. Voltage should increase from 0 to 5.5 volts as ac-celerator is actuated.

Contactor Coils Disconnect wire from one end of the coil terminal.

Connect meter on the R X 1 scale. Meter should read as follows: Forward & Reverse Coils 1 A CoiI Pump Coil Power Steering Coil Switches

27.1 ohms 27.1 ohms 15.6 ohms 27.1 ohms

Sheet 2: Electrical System Disconnect the 14-pin connector from card when checking the following switches: 1.

KEY SWITCH Connect meter from positive terminal on truck battery plug to pin 1-11.

Should read 0 ohms when key is closed.

This also checks FU-2 and small 5 amp fuse (FU-3).

2.

FORWARD DIRECTIONAL SWITCH Connect meter from pin 1-3 to 1-7.

Should read 0 ohms when forward switch is closed (see Note below).

Will read 32 ohms when the reverse switch is closed, which is checking con-tinuity through both directional coils. If lower reading is obtained, check Diode D5 and both directional coils.

3.

REVERSE DIRECTIONAL SWITCH Connect meter from pin 1-3 to 1-6.

Should read 0 ohms when reverse switch is closed (see Note below).

Should read 32 ohms when the forward switch is closed. If lower reading is obtained, check Diode D5 and both directional coils.

NOTE: If there is no continuity in either the for-ward or reverse switches, check the parking and service brake switches.

4.

MS-2 (1A SWITCH) Connect meter from pins 1-12 to 1-4.

Should read 0 ohms when MS-2 closed.

Varistor This is a spike suppression device con-nected in parallel to each contactor coil. It should normally have a very high resistance on the R X 10, 000 scale.

Logic Card Check for continuity between the follow-ing pairs of pin connections: 1 -11 to 2-4 1 -10 to 2-5—Continuity in one direction and infinity in the other.

1 -8 to 2-11 1-8 to 2-12 1-3 to 2-10 2-1 to 2-9—With battery plugged in and key turned on.

Check for oscillator output by checking for voltage at pin 2-17 while operating the truck through the SCR range.

Voltage should increase from zero to ap-proximately 1.5 volts as accelerator is rotated.

Voltage at pin 2-15 should decrease from 1.5 volts to 0 volts as the accelerator is rotated.

SCR TROUBLESHOOTING GUIDE Following are troubleshooting charts to cover the most common fault symptoms that could occur on the ESC drive control

Sheet 2: Electrical System system. Most all of the tests can be made at the 14-pin and 17-pin logic card connector plugs with a simple volt-ohm meter.

Refer to the previous section on Component Test Procedures when check-ing components. Before troubleshooting, always observe the following procedures and precautions: 1.

Check battery specific gravity.

2.

Check battery plug polarity.

3.

Jack drive wheel off floor.

4.

Check for welded contactors.

5.

Visually inspect wiring, plug connectors, switch operation and accelerator linkage.

SCR TROUBLESHOOTING GUIDE

Sheet 2: Electrical System

Sheet 2: Electrical System

Sheet 2: Electrical System

Sheet 2: Electrical System

Miscellaneous Symptoms Check 1. a. Contactor coils b.

Directional switches c.

Battery voltage at pins 1-7 and 1-6 when forward and reverse switches are closed d.

Contact tips Slower than normal SCR speed 2. a. Accelerator pot bad or out of adjustment. b.

Shorted plugging diode (D3) c.

Open flyback diode (D4) d.

Open #10 wire from logic card pin 1-1 to D3 pigtail e.

Overheated or open thermistor Main power fuse burns rapidly. (Also possible damage to 1 3. a. Flyback diode (D4) shorted REC) Truck stops when MS-2 is closed 4. a. Check 1A contactor for mechanical binding, burnt tips or broken wiring.

Severe (stiff) plugging 5. a. Open diode D3 b.

Replace logic card if D3 is good No SCR, Jumps into 1A 6. Open Thermoprotector

Symptom 1. Motor operates in only one direction

2.

3.

4.

5.

6.

1.

1 REC MOUNTING PROCEDURE—("PRESS-PAK" SCR) All "press-pak" type SCR's require special mounting procedures to ensure good heat and electrical conduction. First, it is

Sheet 2: Electrical System important that the upper and lower heat sinks are mounted parallel to each other; and secondly, the SCR's must have pressure applied to them by the heat sink mounting bolts.

Procedure for the 1REC on the Super PC-8 Panel STEP 1 Ensure that the seating areas are clean and free from surface marks.

STEP 2 Check that the roll pin is in position in the heat sink, and that the pin does not pro-ject more than 1.5 mm (little less than 1/1 6").

STEP 3 Apply a thin layer of heat sink grease to both heat sink mounting surfaces, and position the SCR on the roll pin with the cathode side facing up.

STEP 4 With the SCR positively located between the two heat sinks, place the clamp in position and tighten the nuts evenly until finger tight, then tighten with a wrench an additional 1/2 turn. Place the force indicator gauge (part no. 5183538-48) against the spring so that both ends and the middle are in solid contact. Tighten each bolt 1/4 turn alternately until the two edges of the gauge line up at the HW 1000 position. Refer to Figure 2-7.

NOTE: If excessive force has been applied, loosen nuts and start over. Never try to adjust spring force by backing off the bolts, as spring friction will produce a false reading.

Figure 2-7—Force Indicator Gauge DRIVE AND HYDRAULIC PUMP MOTORS The Best Performance from Electric Motors can be Obtained by Following These Precautions: a.

Periodically blow out all motors with compressed air.

b.

Inspect brushes and commutator.

c.

The commutator should be perfectly smooth and a rich chocolate brown color.

d.

The brushes must be replaced when they are worn down to half their original length.

e.

When ordering motor parts, be sure to state model number of truck, serial number of truck, model number of motor and voltage.

f.

In case the brushes are to be replaced, be sure all brushes are changed and properly seated.

Sheet 2: Electrical System g.

Brushes must not be too tight in brush holders.

h.

Check for oil or dirt in motor.

i.

Check to make sure pole pieces are tight.

j.

Check bearings for retention of lubricant.

WARNING: Make sure motor covers, if used, are replaced before operating truck.

PREVENTIVE MAINTENANCE Preventive maintenance on electric motors is recommended to be performed at 200-hour intervals under normal operating conditions.

Under heavy duty, dusty and dirty conditions, preventive maintenance on electric motors must be performed more fre-quently, depending on the conditions and the environment the electric truck is running in.

Proper electric motor preventive maintenance will aid in detect-ing many problems before they become serious.

Maximum performance from electric motors and reduced maintenance costs can be obtained by performing the following periodic preventive maintenance checks—which can be performed on motors while in the truck: a.

Disconnect battery while checking electrical connections.

b.

Remove cover for access to drive motor.

c.

Remove cover for access to hydraulic pump motor.

1.

Cleanliness

Electric motors must be kept clean and dry internally and exter-nally; free of dust, dirt, grease, oil, chemicals, moisture, water, carbon dust, and metallic chips. Blow off contamination with com-pressed air. If internal oil or grease contamination is present, the motor should be disassembled and the individual parts washed in a suitable cleaning solvent.

2.

Connections

Check every screw, bolt, and nut for tightness. Especially check the pigtails of the brushes, the brush holders, power lead con-nections, and field jumper connections.

3.

Discoloration and Burn Marks.

Discoloration and burn marks usually indicate that the motor or certain components of the motor have been overheated—due to stalled conditions, loose connections, insulation breakdown, or contamination. If signs of overheating are present, determine the cause and perform necessary repairs. The commutator should be smooth, free of burn marks, and have a chocolate brown color.

Inspect the brushes, the brush holders, the brush springs, and the insulation for discoloration.

4.

Brushes

Brushes should be inspected to make certain they are not worn down below half the original length. The brushes must be free to move in the brush holders and should not have too much clearance. Check the brush springs for proper tension. If the brushes have to be replaced, use only specified brushes for a specific motor.

5.

Commutator

Check that carbon dust and other foreign matter is not caked on the undercut mica between the copper bars.

The mica separators should be below the segment face. There should not be any thrown solder from the armature risers.

If grease, oil, or corrosive materials are present, clean with a suitable solvent and take the necessary steps to prevent reappearance.

Sheet 2: Electrical System 6.

Bearings

Check bearings for noise and rough spots while the armature is rotating. Inspect the bearings for damaged seals. Sealed bear-ings with high temperature lubricants should be used if replace-ment is required.

CAUSES OF MOTOR FAILURE 1.

Overload

Motors have a specific rating of voltage and current at which they are designed to operate. Should a motor be subjected to a severe overload for substantial periods of time, overheating will result. Pushing loads, working on ramps of too steep a grade, and attempting to lift loads greater than the capacity of the truck are just a few overload conditions. The end result of this overheating is the throwing out of solder in the commutator riser, and bear-ing failure due to excessive heat.

2.

Shock Loading

Shock loading can result from severe (stiff) plugging of the drive motor. This will cause excessive current draw, as the motor at the time of plugging is at stall point. Breaking of the armature shaft could result from plugging.

3.

Short in Field Coils

A short in the field coil or coils causes excessive current draw, again resulting in too much heat. When the truck runs faster than normal, but with little or no torque, it is an indication of a short in the field coils.

4.

Short in Armature

A shorted armature or coils will increase the current draw. A visual inspection of the commutator will show burn marks on the commutator bars connected to the shorted coil or coils.

5.

Short Brushes

Short brushes cause arcing on the commutator and excessive heat. In addition to brush replacement, turning and undercutting of the commutator may be all that is required, provided the damage is not too great.

6.

High or Low Commutator Bar

When one of the bars is protruding above or lying the normal diameter of the commutator, the result is excessive brush wear and arcing of the brushes. Usually a clicking sound will be heard when armature is rotating.

7.

Open Circuit

An open circuit in the field or armature coils of the motor.

8.

Low Battery Voltage

Low voltage causes excessive current draw and increased heating.

9.

Eccentricity of Commutator

Eccentricity of commutator causes rapid brush wear, excessive sparking of brushes, and increased heating.

10. Over-Speeding Over-speeding of the motor by operating with no load (drive wheels off floor) for more than 30 seconds, or pushing or towing of the truck at more than 5 mph will result in failure of the armature.

MOTOR TESTS When testing electric motors for grounds and shorts in the truck, disconnect armature and field leads from the motor Use an ohmmeter, RX10 or RX100 scale, to check for grounds or shorts in the motor.

The ohmmeter should indicate: 1.

A closed circuit between the armature terminals.

2.

A closed circuit between the field terminals.

Sheet 2: Electrical System 3.

Infinity between the motor housing and the armature terminals.

4.

Infinity between the motor housing and the field terminals.

5.

Infinity between the armature and the field terminals (series wound motors only).

If ohmmeter readings are obtained, further checks should be made by a qualified electric motor repairman to find the problem and make the necessary repairs.

PREPARATION OF MOTOR COMMUTATOR 1.

In order to ensure the best possible operation from newlyfitted brushes, the commutator should be in good condition.

Check the commutator for: A. Dirt or other foreign matter.

B. Eccentricity.

C. High or low bars, roughness or burning.

D. High mica.

E. Grooving of commutator.

If any of the above conditions exist, they should be remedied as follows: 2.

Clean the commutator by holding a piece of dry canvas or other hard non-liming material, which is wound around and securely fastened to a piece of wood, against the commutator.

3.

If the eccentricity or roughness is not too great, it may be possible to polish the commutator with one of the several varieties of dressing stones available on the market. Before stoning, clean grease and oil from the commutator using a cloth saturated with a suitable solution. After stoning, the commutator should be smoothed with a very fine grade of sandpaper, and then polished by using the back of the paper. When the commutator is too rough or eccentric to be stoned down, it is advisable to turn the commutator on a lathe.

4.

Undercut the mica using one of the several types of under-cutting tools available on the market. Undercutting is usually done to a depth of 3/64". It is well to slightly bevel the segment corners.

5.

A commutator that is badly grooved should be ground or turned the same as for roughness or eccentricity. After the commutator has been conditioned, make sure that it is com-pletely cleaned out by suction (preferred), or by blowing out with clean, dry compressed air.

Using undercutting tool removes all traces of insulator along the conducting slots.

Insulator

Using hacksaw may leave ridges of insulator along the edges of the conducting slots, causing arching, chatter, and rapid brush wear.

Insulator

Figure 2-7a

FITTING MOTOR BRUSHES

Sheet 2: Electrical System 1.

Care that is taken to ensure the best possible commutator and brush running conditions, mechanically and otherwise, will pay dividends in longer brush and commutator life along with improved commutation.

2.

Brushes of different qualities should never be run together on the same commutator. Using brushes of improper com-pound, or brushes other than those originally specified and manufactured for a specific motor, will cause commutator damage.

3.

Before installing brushes, inspect the brush holders inside and out for burned spots. Make sure that the brush pigtails are properly secured to the brushes, and that the brushes move freely in the brush holders.

4.

Fit the new brushes to the commutator surface by using a strip of fine sandpaper placed between the face of the brush and the commutator (sand surface against brush). Use several one-direction strokes of the sandpaper, pulled in the direction the commutator rotates with the forward direction of the truck (drive motor), and in the direction in which the commutator rotates while hoisting (hoist pump motor). Only the pressure of the brush should be on the sandpaper when it is fitted in this matter.

5.

Following the installation of new brushes, the motor should be blown out with clean, dry compressed air.

Figure 2-8—Drive Motor Commutator End Head & Brush Assembly DRIVE MOTOR—REMOVAL AND INSTALLATION a. b. c. d. e. f. g. h.

Disconnect battery.

Remove compartment cover.

Tag and disconnect motor wires and brake linkage.

Remove harness clamp from end head, and move harness to the side.

Remove four bolts that secure motor to the drive unit.

Tap motor lightly with a mallet to separate from drive unit.

Lift motor up and off drive unit.

Upon installation, replace gasket between motor and drive unit.

Sheet 2: Electrical System

Figure 2-9—Drive Motor Brush Removal DRIVE MOTOR—BRUSH REMOVAL AND INSTALLATION Refer to Drive Motor and Brush Removal Figures. a.

Disconnect battery.

b.

Open compartment covers.

c.

Remove screws securing motor cover plates, if equipped.

d.

Note position of brush and wire assemblies before removing. When installing brush set, be certain to place brush set and wires in same position as removed.

e.

Loosen round head screw and washer securing brush wire to terminal. Remove brush springs and brush set.

f.

Reverse above to install. Refer to Fitting Brushes paragraph in this section.

DRIVE MOTOR BRUSH HOLDER— REMOVAL AND INSTALLATION Refer to Drive Motor and Brush Holder Figures. a.

Disconnect battery.

b.

Remove compartment cover.

c.

Remove brush assemblies.

d.

Scribe motor field ring housing and commutator end head to make certain end head is installed in same posi-tion as removed.

e.

Tag and disconnect drive motor wires from upper 2 terminals.

f.

Remove hex head screws securing end head to field ring. It will be necessary to rotate drive unit for easier access to all screws.

g.

Remove end head assembly.

NOTE: It may be necessary to use a puller to start the end head off the bearing when removing. Do not force, or damage to the end head may result. h.

Remove 3 hex head screws securing brush holder assembly to end head. Inspect all parts for wear or damage, and replace when necessary.

i.

Reverse above to install.

NOTE: Do not drive on end head when installing. Lightly tap using a plastic hammer.

DRIVE MOTOR INSPECTION

Sheet 2: Electrical System 1.

Check commutator for grounds, shorts, and uneven wear.

2.

Check bearings; replace if worn or damaged.

3.

Check field coils.

4.

Check brush holder/assembly.

5.

Replace lock nuts on each end of armature shaft.

Figure 2-10—Drive Motor ITEM DESCRIPTION 1. Bearing 2. Commutator End Head 3. Brush Set 4. Brush Holder Assembly—Only 5. 1/4" -20 x 3/4" Long Hex Screw—Cadmium Plate, 1/4" Flat Washer, 1/4" Lockwasher 6. Terminal Screw Package 7. Brush Spring Set 8. Terminal Assembly Package 9. Drive End Head 10. Pole Piece 11. 3/8" -16 x 1-1/4" Long Hex Screw—Gd. 5, 3/8" Lockwasher 12. Field Coil Set 13. Insulator With Slot, Insulator Without Slot 14. 1/4" -20 x 1" Long Hex Screw—Gd. 5, 1/4" Lockwasher 15. Armature Assembly Shaft 16. Field Ring 17. 3/8" x 2-1/4" Lg. Hex Screw—Gd. 5, 3/8" Lockwasher 18. Bearing Retainer 19. 20 x 1/2" Long Self-Locking Screw 20. 1/4" -20 Elastic Stop Nut 21. Bearing DRIVE MOTOR—DISASSEMBLY AND ASSEMBLY Refer To Drive Motor Figures a.

Clean and punch mark (or scribe) drive and commutator end heads and motor field ring housing to simplify reassembly of the motor.

b.

Remove brushes and spring assemblies.

c.

Remove elastic stop nut (20) and pinion gear and shims, using a socket and impact wrench.

NOTE: When same motor pinion is used, replace shim or shims in same position as removed.

Sheet 2: Electrical System d.

When a new pinion and bevel gear set is used, refer to Drive Unit Section for gear setting.

e.

Remove hex head screws securing commutator end head. Remove end head. It may be necessary to use a puller to remove.

Do not force, or damage to the end head may result.

f.

Remove hex head screws securing drive end head. Tap end head loose using a plastic hammer and remove, complete with armature.

IMPORTANT: Be extremely careful not to damage the field coils, pole pieces or armature when removing. g.

Remove hex head screws securing bearing retainer. Remove bearing retainer from drive end head.

h.

Separate drive end head from armature. End head will come off with bearing. It may be necessary to use a puller to remove. Do not force, or damage to the end head may result.

i.

Remove screws securing brush holder assembly to commutator end head. Remove brush holder assembly.

j.

Remove bearings from end heads when worn or damaged.

k.

Replace field coils when necessary.

l.

Reverse above to install, using new elastic nut to secure motor pinion gear.

Figure 2-11—Hydraulic Pump Motor ITEM DESCRIPTION 1. Cover band 2. Commutator end head 3. Thrust washer package 4. Commutator end ball bearings 5. Brush plate assembly 6. Brush spring set 7. Brush se' 8. Field coil set 9. Terminal stud set 10. Drive end head 11. Drive end ball bearing 12. Fan 13. Armature HYDRAULIC PUMP MOTOR— MAINTENANCE INSTRUCTIONS 1.

Lubrication—Pre-lubricated ball bearings are supplied. Replace only with original equipment.

2.

Motor brushes need periodic inspection and replacement as wear indicates. Brush wear is greatly influenced by indi-vidual application, so it is recommended that the brush wear be checked open to determine future required inspection. Standard brushes have a length of 1-1/4 inches. When the brushes are worn to a length of 5/8 inches, they should be replaced.

Sheet 2: Electrical System 3.

If mechanical or electrical failure occurs, first check for pro-per electrical connections, fusing, or unusual binding of mechanical load. Starting and accelerating torque's of per-manent magnet D. C. motors are considerably higher than the full load torque of the motor. Care should be taken to prevent damage to driven machinery as a result of the higher starting and accelerating torque's.

BRUSH REPLACEMENT (See Figure 2-11) a.

Disconnect battery.

b.

Remove compartment covers.

c.

Mark commutator end head (2) and frame for reassembly.

d.

Remove four cap screws (with 1/4" socket) and end head.

e.

Unclip brush springs (6).

f.

Remove two brush retaining screws.

g.

Remove brushes (7) and inspect armature for welds or raised commutator bars.

h.

To install new brushes, reverse operations.

BRUSH HOLDER REPLACEMENT a.

Follow Brush Replacement steps a, b, c and d above.

b.

Remove cover band (1).

c.

Remove four nuts that hold plate assembly (5) to end head (2).

d.

Remove two brush lead screws.

e.

Mark for reassembly and plate assembly from end head and remove plate assembly.

PUMP MOTOR REMOVAL a.

Disconnect battery.

b.

Operate hydraulics to eliminate pressure.

c.

Remove compartment covers.

d.

Tag and disconnect wires.

e.

Drain and remove hoses.

f.

Remove four pump mounting bolts with 8 mm or 5/16" 12-point box wrench.

g.

Remove motor mounting bolts, and carefully lift motor from pump. Do not lose coupler.

h.

For installation, reverse above procedure. Apply a liberal amount of grease to the coupler and cavity, line up the coupler, and install.

INSPECTION a.

Remove both end heads from motor.

b.

Remove armature and check for opens, shorts and grounds. Refer to Motor Tests on Page 2-17.

c.

Check commutator for wear and raised segments.

d.

Replace bearings and brushes.

e.

Check field coils.

Sheet 2: Electrical System f.

Check brushes and holder; replace worn or defective parts.

MOTOR INSTALLATION 1.

Before making electrical power connections, check for proper grounding of the motor. All electrical contacts and connections must be properly insulated and enclosed. Couplings must be in proper alignment, balanced, guarded, and secured to ensure safe motor operation.

2.

Prior to connecting power, refer to motor name plate for proper voltage and rating information. If rotation must be changed, simply reverse leads.

3.

Motor must be kept dry and provided with adequate ventilation.

POWER STEER MOTOR a.

Read motor nameplate. Take special note of the rated voltage.

b.

Attempt to turn the shaft by hand. If the shaft turns freely go on to step d. If it does not, proceed to step c.

c.

To check if shaft tightness is a temporary condition, apply 24 volts to the motor while observing polarity. Do not connect or disconnect wires with the power on, since arcing at the terminals can occur. This will cause rough threads.

If motor sounds normal go to next step. If noise is excessive, however, repair or replacement will be necessary.

d.

If the motor ran freely with rated voltage applied, connect an ammeter in the circuit as shown in Figure 2-13 with rated voltage applied—24 V and the shaft running free. The ammeter should read 2.6 max. amps. Check speed also—1700 R. P. M. If the motor performs to these specifications it can be assumed the problem is not in the motor. At full load (relief pressure), amp draw will be 39 amps.

CAUTION: This motor should be disassembled in an extremely clean area free of any ferrous metal chips, as the magnet pole pieces will attract them and cause serious damage to the motor.

Figure 2-12—Power Steer Motor 1. Wave Washer 2. Bearing—Commutator End 3. Thru Bolt 4. Terminal Bolt Assembly 5. Frame & Magnet Assembly 6. Armature Assembly 7. Fan 8. Thru Bolt 9. Bearing Spacer 10. Shim 11. Bearing—Drive End 12. Drive End Head 13. Brush Plate Assembly— Includes Brushes & Clips 14. Cover 15. Cover Insulator 16. Commutator End Head

Sheet 2: Electrical System STEER MOTOR DISASSEMBLY a.

Remove screws that retain pump to motor.

b.

Remove brush covers and slip brushes back into their holders.

c.

Remove 4 long screws on top of the commutator endhead. Scribe lines to mark different sections of the motor.

d.

With a plastic mallet gently tap and remove the com-mutator end head.

e.

Remove the hex head bolts that hold the pump drive end head to the armature.

f.

Pull the armature and drive end head out of the motor body and field assembly.

Figure 2-13—Ammeter Connection POWER STEER MOTOR INSPECTION a.

Bearings—Should spin freely, have ample lubrication and be free of corrosion.

b.

Armature—Check for grounds and shorted turns, look for signs of heat.

c.

Brushes—Replace and remove dust or dirt from brush ring. Be sure brushes are free in their holders.

d.

Stator—Check magnets to see if they are securely mounted.

e.

Inspect wire harness and all connections.

CAUTION: The fields in this motor are permanent magnets. Be careful not to place fingers between the drive end head and the field ring since the magnetic pull of the fields will try to pull the armature back into the motor. Remove the armature with one swift, continuous motion.

WIRING DIAGRAM—E

Sheet 2: Electrical System

WIRING DIAGRAM—E ITEM

PART NO.

DESCRIPTION NO. REQD.

A

5040955-00

Harness—Control Switch

Sheet 2: Electrical System 1 B

5169106-00

Harness—Instrument Panel 1

C

5034047-00

Harness—Control 1

POWER WIRE GROUP ITEM

PART NO.

DESCRIPTION NO. REQD.

1

5021649-09

#4Wire—113" Lg 2

0124719-00

Terminal—For 5/16" Dia.

Stud

2 0124740-00

Terminal—For 3/8" Dia.

Stud

2 2

5021649-09

#4 Wire—109" Lg 2 Terminal—For 1/4"

Dia. Stud

2 0124740-00

Terminal—For 3/8" Dia.

Stud

2

3 —SB-350-Red & Gray

5021649-07

#2/0 Wire—23-1/2" Lg. 1

0124722-00

Terminal—For 5/16" Dia.

Stud

1

4 —SB-350-Red & Gray

5021649-07

#2/0 Wire—18-1 /2" Lg. 1

0124722-00

Terminal—For 5/16" Dia.

Stud

1 3

5021649-07

#2/0 Wire—29" Lg. —EC 1

0124722-00 Stud

.

4

Terminal—For 5/16" Dia. 1

5021649-07

#2/0 Wire—24" Lg. —EC 1

0124722-00

Terminal—For 5/16" Dia.

Stud .....

1 5 ...

0116616-00 .

..

#8 Wire—40" Lg ......

1

5020269-02 Stud

Terminal—For 1/4" Dia. 1 Terminal—For 1/4"

Dia Stud

1 6

0116616-00

#8 Wire—48-3/4" Lg 1

5020269-02

Terminal—For 1/4" Dia Stud 1

5020269-03 Stud

Terminal—For 5/16" Dia. 1

7

5021649-08

#2 Wire—42-3/4" Lg 1

0124710-00 Stud

Terminal—For 1 /4" Dia. 1

0124720-00 Stud

Terminal—For 5/16" Dia. 1

8

5021649-08

#2 Wire—38-1 /4" Lg 1

0124710-00 Stud

Terminal—For 1 /4" Dia. 1

0124720-00 Stud

Terminal—For 5/16" Dia. 1

FIELD WEAKENING-OPTIONAL

Sheet 2: Electrical System ITEM

PART NO.

DESCRIPTION NO. REQD.

9

5194818-00

Wire Assembly 1

10

5027752-00

Resistor—Shunt 1

11

5012703-05

12

5027122-00

Contactor 1 Field Weakening Unit 1

5043335-00 13

Bracket 1 Wire Harness

5170196-00 1

Sheet 2: Electrical System

ATTACHMENT & ACCESSORIES WIRING

Sheet 1: General Truck Lubrication

GENERAL TRUCK & LUBRICATION OPERATOR PRECHECKS AND INSPECTION It is the operator's responsibility to carry out the following checks and inspections before beginning truck operations.

Do not operate truck if it is in need of repair. If it is in an unsafe condition, or if it 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.

1.

Make sure overhead guard, load backrest extension, and any other safety devices are attached.

2.

Make sure all capacity, safety, and warning plates or decals are attached.

3.

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

4.

Inspect truck both before and after operating truck, for any signs of external leaking; battery, steering system, or hydraulic system.

5.

Operate service and parking brakes, all hydraulic controls (hoist, tilt, and auxiliary, if equipped), accelerator, shifting linkages and steering system. Make sure they operate freely and return to their proper positions.

6.

Inspect condition of tires.

7.

Inspect forks. Make sure they are properly attached and locking clips are locked in their proper position.

8.

Test horn, lights, and all 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.

SHUTDOWN PROCEDURE When leaving truck unattended, lifting mechanism shall be fully lowered, controls neutralized, power shut off, brakes set, key removed and battery connector disconnected. Block wheels if truck is parked on an incline.

DANGER

WARNING

CAUTION

These symbols are used in all Yale service literature to indicate that special care must be exercised by mechanics before attempting repairs or adjustments. This special care is safety related and must be adhered to in order to insure the safety of all personnel. Our manuals describe the safe way to perform maintenance on our trucks.

CAUTION: Before operating this truck read and observe safety information in your Yale operating instruction booklet. Your Yale truck as manufactured meets all the applicable mandatory requirements of ANSI B56.1-1983 Part III Safety Standard. All Standard Trucks conform to the Underwriters' Laboratories requirements for the type designation shown on the capacity plate.

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 under-stand each one, and read the maintenance procedures before attempting to repair the truck. When in doubt about any maintenance procedure, contact your local Yale dealer.

CAUTION: If this truck is to be operated closer than 1 meter to equipment transmitting in the frequency range of 25 kHz to 150 MHz, or if the transmitter power exceeds 5 watts, additional electromagnetic shielding may be required on the truck to prevent interference with the traction control operation.

Sheet 1: General Truck Lubrication COMPONENT REMOVAL Load Backrest

Figure 1-1—General Truck ITEM

DESCRIPTION

1. High-Visibility Mast Assembly 2. Carriage Assembly 3. Load Wheels 4. Battery 5. Battery Compartment 6. Steer Handle 7. Operator's Compartment 8. Tilt and Auxiliary Handles 9. Hoist and Drive Controller 10. Lift Cylinders 11. Drive and Steer Wheel a.

Remove hex head screws on side of load backrest.

b.

Lift load backrest up and off carriage assembly.

Load Forks a.

Lift lock pin and slide forks one at a time to center of carriage.

b.

Tilt up toe of fork and place block under heel.

c.

Push down on toe and fork should lift off of carriage.

Overhead Canopy Guard a.

Attach overhead hoist to overhead guard.

Sheet 1: General Truck Lubrication b.

Remove hex head bolts on rear canopy legs and hex head bolts and nuts on front canopy legs.

c.

Lift canopy up and off of truck.

Counterweight On the ESC-A, counterweights are part of the frame—and need not be removed.

Battery a.

Disconnect battery plug.

b.

Attach overhead hoist and a proper battery lifter to battery..

c.

Lift up and slide out of battery compartment.

If truck is so equipped, battery may be rolled out of compartment.

COMPONENTS Controls Forward, reverse, speed, Iift, and lower controls are conveniently contained in a single controller handle. The tilt handle is also located within inches for fingertip control. All controls are easily operated even while wearing work gloves.

Electrical Wiring Plug-in wiring harnesses help eliminate shorts, and simplify maintenance.

Load Wheels The large polyurethane or rubber load wheels provide a greater load-bearing surface than most other trucks on the market.

Forks The forks are fabricated from heavy gauge steel and are designed for easy entry and exit from under loads.

Drive Unit Tire class "H" insulated drive unit does not use belts or chains to transfer torque to the drive wheel. The unit is gear-driven and is cradled in a 72-ball bearing race.

Components General Contactors, lift pump, and other components are mounted on a frame plate within the compartment located in front of the battery for easier maintenance.

SYSTEMS IDENTIFICATION Each truck consists of seven systems that power and control truck operation.

• • • • • • •

Electrical System Drive Unit Brake System Control Handle Assembly Mast Assembly and Load Wheels Hydraulic System Battery and Charging System

The systems are described as follows: Electrical System The electrical system operates every system and function on the truck—travel, lifting, and tilting. Electrical power to the drive motor is controlled by a Cableform Super PC-8 SCR system.

Sheet 1: General Truck Lubrication Drive Unit The drive unit generates the power needed to propel the truck through all speeds.

Brake System The brake components mounted on the drive unit and in each load wheel provide the braking power needed to stop truck motion.

Control Handle Assembly The handle contains the control switches and is used during all operations.

Mast Assembly and Load Wheels The mast carriage and uprights transfer hydraulic lift cylinder movement to the forks (lift or lower). The load wheels support the load.

Hydraulic System The hydraulic system generates the hydraulic pressure needed to operate the lift and tilt cylinders. A separate hydraulic system operates the power steer system.

Battery and Charging System The storage battery supplies the electrical power needed to operate all switches, controls, and motors on the truck. The charging system is used to recharge the batteries after prolonged use.

GENERAL MAINTENANCE Read and observe the following before performing any maintenance procedure.

WARNING 1.

Be certain to refer to description of parts on all illustrations to avoid the possibility of stripping threads when replacing screws, studs or nuts.

2.

For all torque specifications, unless otherwise listed, refer to the Torque Specifications Charts on Page 1-12 to 1-14 of this manual.

3.

This electric-powered industrial truck may become hazardous if adequate maintenance is neglected. Therefore, adequate maintenance facilities, personnel, and procedures should be provided.

4.

Refer to the Recommended Schedule of Maintenance found on Page 1-9 to 1-11 of this manual when inspecting and servicing these trucks.

5.

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

6.

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

7.

Brakes, steering mechanism, control mechanism, warning devices, lift and speed limit devices, and guards and safety devices should be inspected regularly and maintained in a safe operating condition.

8.

Before performing any maintenance procedure, raise the drive wheel off the floor and support it in this position using chocks or other positive truck positioning devices. When ap-plicable, the battery should also be disconnected.

9.

The hydraulic system should be inspected regularly and maintained in conformance with good practice. Hoist 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.

10. When working on hydraulic system components, turn off power to the truck, and ensure that the lift cylinder is in its lowered position and that hydraulic pressure has been re-lieved in hoses and tubes.

Sheet 1: General Truck Lubrication 11. Before removing any component from the truck make sure that the lifting mechanism (hoist) and slings used to remove it are of the proper capacity and in good condition.

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

13. Capacity, operation, and maintenance instruction plates, tags, and decals should be maintained in legible condition.

14. Operation to check performance of the truck should be con-ducted in an authorized, safe clearance area.

15. Always use Yale replacement parts in order to ensure interchangeability and component quality.

16. Avoid fire hazards and have fire protection equipment present when performing maintenance on these trucks. Do not use an open flame when checking battery level or when checking for electrolyte leakage. Do not use open pans of fuel or flammable cleaning fluids when cleaning parts.

17. All lift mechanisms and frame members should be carefully and regularly inspected and maintained in a safe operating condition.

18. Special trucks or devices designed and approved for hazardous area operation should receive special attention to ensure continued serviceability.

19. Modifications and additions that affect capacity and safe truck operation should not be performed by the customer or user without the manufacturer's prior written approval. Capacity, operation, and maintenance instruction plates, tags or decals should be changed accordingly.

ASSEMBLY AND DISASSEMBLY OF COVERS AND GENERAL COMPONENTS Drive Unit Cover • Disconnect battery • Remove six screws • Tilt Cover Back • Step down on parking brake pedal • Lift cover up and out SCR Control Cover • Disconnect battery • Loosen two screws • Remove cover Control Handle Covers • Disconnect battery • Remove seven trim screws • Remove control handle links • Remove four cowl screws • Remove wires from key switch • Separate control handle plug • Separate battery discharge indicator plug • Remove handle for service RECOMMENDED SCHEDULE OF MAINTENANCE, ELECTRICAL POWERED TRUCK Timely care and maintenance, commencing upon delivery and installation by a Yale factory trained mechanic, will insure the maximum service life of your Yale lift truck. The recommenda-tions herein are based on our years of experience in serving your material handling needs for maximum safety, productivity and economy.

We recommend that your lift truck operator perform the daily Safety and Operational checks listed, and have a qualified mechanic correct all discrepancies using genuine Yale or Yale approved parts. Unusual noises or problems should be reported immediately by the operator to his supervisor.

The Yale WARRANTY STATEMENT covering new trucks is available from your Yale dealer. To maintain your Yale WARRANTY In good standing you must follow this schedule and perform the daily safety and operational checks as well as the maintenance functions outlined herein. If you require a Warranty Repair, you must contact your Yale dealer for Warranty Service during the periods outlined in the Warranty Statement. Your Yale dealer has complete details on what components are covered and the types of repairs that are warrantable. When in doubt about your warranty coverage, contact your dealer.

Sheet 1: General Truck Lubrication All new Yale trucks will be provided with a STANDARD PARTS MANUAL through your Yale dealer. Additional STANDARD PARTS MANUALS, SPECIAL PARTS MANUALS, and SERVICE MAINTENANCE MANUALS are also available from your Yale dealer for a nominal charge. For the optimum in professional repair and maintenance, we recommend your Yale dealer's factory trained mechanics for Yale service and a Yale Maintenance Agreement.

NOTE: The Occupational Safety and Health Act (OSHA) requires are in safe working order.

that the user examine his trucks before each shift they

The daily SAFETY AND OPERATIONAL CHECKS listed in this publication are available in pad form at a nominal cost from your Yale dealer.

This recommended schedule of maintenance is based on a clean, average single-shift operation. For unusually dusty air, dirty floors, excessive heat or cold, multi-shift or generally more severe opera-tions, maintenance intervals must be more frequent.

Electric-powered trucks require special emphasis in the main-tenance of the battery and the electric motors. The battery, battery compartment, electronic control and drive motors should be kept clean, free of dust and corrosion. All wire connections must be clean and tight. A battery charging and maintenance program should be pursued. Compliance with these requirements will save you money and extend the life of your truck.

CHECKING LIFT TRUCK TRAVEL SPEED Lift truck travel speed should be checked when a problem with acceleration is suspected.

Published travel speeds are determined by tests conducted on a dry concrete track with trucks in good running condition.

Travel speed for an electric-powered unit is affected by battery charge, motor condition, amp draw, electronic control adjustment, tire type, and condition. All tests for electric trucks are at full battery voltage.

Speed can also be affected by dragging brakes, bad wheel bear-ings and floor conditions. All of these items must be corrected before testing.

For safety, the load must be securely chained in place, and warn-ing that a speed test is being performed must be placed to alert other personnel at intersection points.

The following is the recommended procedure for checking travel speed for Yale trucks: 1.

Measure distance of 88' (88' is 1/60 of a mile). Allow a running start of 100 feet before start of test, and allow adequate stopping distances.

2.

Allow the truck to reach full speed before crossing the starting line.

3.

Make three (3) round trips empty and three (3) round trips loaded, checking the time with a stop watch or sweep second hand.

4.

Average the accumulated times.

5.

Divide the number of seconds, in the empty condition, into 60 to obtain the truck speed in M. P. H.

6.

Repeat step 5 for loaded condition.

7.

Record the following: c. d. e. f. g. h. i. j.

Model and Serial number.

Specific gravity of battery (state of charge).

Type of tire—steel, poly, etc. - will affect speed.

Condition of floor.

Average speed loaded (full capacity).

Average speed empty.

Time in seconds empty.

Time in seconds loaded.

Sheet 1: General Truck Lubrication SERVICE CHECK Complete the following service check after initial installation and after maintenance or repairs. All tests are with a rated load in an area clear of potential hazards. Drive carefully and observe all traffic regulations. All unusual noises must be investigated immediately.

General Condition Brakes

Visual check.

Test for stopping and fluid level.

Gear Noises

Check fluid levels.

Acceleration

Refer to "Checking Travel Speed" at left on this page

Inching Lifting (hoist)

Check with rated load Check with rated load at 24-inch load center. Raise load and measure down-ward drift in a 2-minute period: It should not exceed 1 inch. Oil temperature should be approximately 70 degrees F.

Tilt minutes.

Attachment Steering STOPPING DISTANCE

Check with rated load, mast vertical. The drift should not exceed 1 degree in 2 Check for proper operation Look for binding or excessive looseness

Sheet 1: General Truck Lubrication

Figure 1-2—Lube Points MAINTENANCE SCHEDULE EVERY 8 HOURS— Perform all safety and operational checks as outlined in the Recommended Schedule of Maintenance also found in this Section.

Check battery level and add water if necessary to maintain the level that is recommended by the manufacturer. A certain amount of water loss in battery cells is normal. Always replace water at the end of a charge. Use approved tap or distilled water.

Sheet 1: General Truck Lubrication EVERY 200 HOURS— Perform the Service Check shown on previous page.

The following Lubrication instructions are for standard ESC Models Trucks used for special applications may be equipped with extra lubrication fittings, covers, special oils, etc. Consult your nearest Authorized Yale dealer when servicing these models.

Refer to both the Recommended Schedule of Maintenance Charts and these Lubrication instructions when inspecting, lubricating, and servicing these models. Also, read and observe all safety and operational precautions outlined in this manual before performing any work on this truck.

IMPORTANT: The interval of time referred to in this schedule of lubrication is based on normal operating conditions. If the vehicle is operated in areas of high contamination such as dust, corrosive vapors, etc. , the interval of time should be adjusted accordingly.

Refer to the appropriate Lubrication List in this section for the oils and grease that are recommended for use on these models.

Apply lithium base, multi-purpose No. 2 grease with a high pressure gun to the following fittings. Clean lube fittings before and after lubricating.

LOCATION OF LUBE FITTINGS 1.

2.

3.

NO. OF FITTINGS

Drive Unit Ring Bearing....................................................4 Articulating Chain Anchors—Carriage (when equipped)* 2 Tilt Cylinder Rod Ends......................................................1 *When truck is equipped with attachment, apply machine oil with flexible spout at chain end of anchor.

Apply engine oil (SAE 20 or 30) to all friction points of the following with an oil can or spray.

DO NOT OVERLUBRICATE 4.

Steering Linkage & Chain

5.

Control Valve Linkage

6.

Mast Pivot Shaft

7.

Tilt Cylinder Pivot Pin

8.

Brake Linkage

9.

Parking Brake Linkage

10. Controller Linkage 11. Hoist Chains—Wipe off all old oil using a clean cloth, then use compressed air to blow off chains.

With a clean brush, apply SAE 30 or 40 weight oil to the full length of chain. Oil must penetrate chain joints.

12. Steer Chain—Perform the operation outlined in Step 11.

13. Mast and Carriage Wear Plugs (All Models)—Remove old grease from mast channel and l-Beams. Use a brush to apply coat of paratac grease with lime or aluminum base to all friction areas.

14. Brake Master Cylinder—Remove rubber boot from reser-voir and check fluid level. Proper level is 1/4" from top of reservoir. Use SAE J-1703 hydraulic brake fluid. Capacity is approximately 1 pint (.47 liter).

15. Hydraulic Oil Level—Use the dipstick in the tank to check the hydraulic oil level. Check the oil level when the oil is at normal operating temperature and mast is in lowered posi-tion. Check dipstick while filling. DO NOT OVERFILL. NOTE: After first 200 hours of operation, the hydraulic oil filter must be changed; then every 1200 hours thereafter.

16. Hydraulic Reservoir Breather—Clean breather with a suitable solvent, blow dry with compressed air and reinstall. Replace breather if damaged or if it cannot be cleaned.

EVERY 400 HOURS—

Sheet 1: General Truck Lubrication 17. Drive Unit—Remove cover. Remove drive unit oil level plug; oil should run out slightly. To add oil, leave oil level plug out. Remove breather in housing top cover. Clean with a suitable solvent and blow dry with compressed air. Replace breather if it cannot be cleaned or is damaged. Add oil into drive unit until oil runs out oil level hole. Replace level plug and breather. DO NOT OVERFILL. EVERY 1200 HOURS— 18. Wheel Bearings—Remove wheel hubs and bearings. Remove old grease and wash all parts thoroughly with sol-vent and dry. DO NOT rotate bearings while dry. Repack by forcing lubricant between the rollers and inner race, filling the spaces between the rollers. The wheel hub cavity be-tween the bearing cups should be packed with the same lubricant to a level even with the inner diameter of the bear-ing cups. Apply a light coat of grease to the spindle and the finished surface on which the oil seal rides. Install the hubs and bearings using the following instructions: Tighten the wheel adjusting nut while slowly rotating the wheel until it is tight. Back off adjusting nut (turn counter-clockwise) 1/16 to 1/4 turn until slot in locknut lines up with hole in axle shaft. Install cotter pin. Hub should turn freely with .001" to .010" end play.

19. Hydraulic Oil Filter—Remove and discard filter element and install new element. Also, refer to Steps 15 & 16.

EVERY 2400 HOURS— 20. Drive Unit—Remove Cover. Remove drain and oil level plugs to drain oil. Replace drain plug. Remove breather in housing top cover and add flushing oil through breather port. Flush housing and remove drain plug to drain flushing oil.

Replace drain plug. Add gear oil through breather port until oil begins to run out oil level hole. Drive unit capacity 1 quart (.95 liter). DO NOT OVERFILL. 21. Hydraulic Oil Tank—Remove drain plug from bottom of tank to drain oil. Perform Steps 16 and 19 before refilling tank.

After filling tank, capacity approximately 5.5 gallons (20.8 liters), fully elevate and tilt mast while bringing oil to normal operating temperature. Lower mast and check oil with the dipstick. DO NOT OVERFILL. Refer to Recom-mended Hydraulic Oil Chart in this section.

Sheet 1: General Truck Lubrication

Sheet 1: General Truck Lubrication

Sheet 1: General Truck Lubrication

GENERAL GUIDE TO TORQUE VALUES

Sheet 1: General Truck Lubrication

NOTES: 1.

The term lub includes the application of high stress lubricants to the fastener, and fasteners that are plated with luberizing cadmium.

2.

Dry values include screws that are only lightly oiled, such as, with a rust preventive oil.

3.

Torque values shown are minimum. Values 20% higher are permissible.

4.

CAUTION: Zinc plated fasteners must be torqued to a value approximately 10% higher than the dry value.

GENERAL GUIDE TO TORQUE VALUES

Sheet 1: General Truck Lubrication

NOTES: 1. When luberizing cadmium plated screws are used or high stress lubricants are applied to the fastener, reduce the dry values by approximately 20%.

2. Dry values include screws that are only lightly oiled, such as, with a rust preventive oil.

3. Torque values as shown are standard. Values 20% higher are permissible.

4. CAUTION: Zinc plated fasteners must be torqued to a value approximately 10% higher than the dry value. * RECOMMENDED MAXIMUM TORQUE VALUES FOR HYDRAULIC FITTINGS * Torque Values Furnished by Air-Way Manufacturing Co. , Olivet, Mlchigan.

Sheet 1: General Truck Lubrication

NOTE: Values shown are for zinc plated fittings. Values for cadmium plated fittings may vary slightly, but not enough to be of any appreciable difference.

Hydraulic Oils

Sheet 1: General Truck Lubrication

Gear Oils

Sheet 1: General Truck Lubrication

Grease

Sheet 1: General Truck Lubrication

Sheet 7: Hydraulic System

HYDRAULIC SYSTEM GENERAL HYDRAULIC SYSTEM INFORMATION The hydraulic system installed in each truck provides the force required to lift loads.

The system consists of the following individual components: Pump Motor Assembly Hydraulic Pump Assembly Lift Cylinders Tilt Cylinder Control Valve Relief Valve Power Steer Pump 8 Motor Reservoir (Tank) Oil Filter TUBING 1.

All pipes and tubing must be thoroughly cleaned before installation.

2.

Tubing must not be bent too sharply. The recommended radius for bends is three times the inside diameter of the tube. The number of bends should be kept to a minimum, to prevent excessive turbulence and friction.

3.

When making repairs, use the smallest 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 power transmission and lubrication. Using the correct fluid is essential to proper system operation. Refer to the Lubrication Charts in the General Truck & Lubrication section of this manual for the oil that must be used.

Oil 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.

Adding Fluid to the System When hydraulic fluid is added to the system, it should be pumped through a 25 micron filter. If such a filter is not available, or impractical to use in the field, a funnel with a fine wire screen (200 mesh or better) can be used.

It is important that oil be clean and free of all substances that might cause improper operation and excessive wear of the pump or other hydraulic units in the system. Be sure to purge all air from the system.

CLEANLINESS Follow these precautionary steps, to ensure that the hydraulic system always remains clean.

HYDRAULIC SYSTEM 1.

Clean (flush) entire system when a failure is encountered, to make sure all paint, metal chips, welding shot, etc. is removed.

2.

Filter each change of oil to prevent the introduction of contaminants into the system.

3.

Provide continuous oil filtration to remove sludge and pro-ducts of wear and corrosion generated during the life of the system.

4.

Provide continuous protection from air-borne contamination by keeping the breather clean and serviceable.

Sheet 7: Hydraulic System 5.

Work on hydraulic assemblies must be done in a clean work area.

SOUND LEVEL Hydraulic system noise is caused by improperly selected fluid and/or loose or damaged system components.

The primary causes of system noise are: — Hydraulic oil with high or moderately high viscosity. At start-up, low temperatures can cause pump noises due to cavitation, which 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. This results in system noise that is similar to cavitation. Aerated fluid is caused by the ingestion of air through the pipe joints of inlet lines and high velocity discharge lines, as well as cylinder rod packings. Aeration can also be caused by fluid discharging above the fluid level in the reservoir.

INSPECTION Periodic inspection of spool operation, oil condition, and pressure connections saves time-consuming breakdowns and unnecessary parts replacement.

1.

All hydraulic connections must be tight. Loose connections not only allow leakage but also permit air to be drawn into the system resulting in noisy and erratic operation.

2.

Spools should return to neutral automatically when the control is released. The standard centering spring force is approximately 28 pounds with the spool in the neutral position, and approximately 56 pounds with the spool in the shifted position. If more force is necessary, the spool may be binding or control linkage may be faulty.

3.

System filters and reservoir should be checked periodically for foreign particles. If excessive contamination is found, the system should be drained. The reservoir must be cleaned thoroughly before refilling.

SYSTEM OPERATION Lifting A Load A load is lifted when the button on the side of the controller is depressed. Depressing this button switch and pulling back on the controller allows current to flow to the pump motor. This current is converted into mechanical energy or torque by this motor.

This torque is transferred to the pump from the motor through the motor shaft and shaft coupling.

Hydraulic fluid is pumped through the system as the pump begins to turn. A vacuum created inside of the pump draws fluid out of the reservoir through the suction line. Air drawn into the reservoir through the breather displaces the pumped fluid, 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.

Fluid that is pushed out of the pump passes first through a directional (check) valve, which is in a normally opened position.

This valve prevents fluid from flowing back to the pump when lifting ceases, keeping the lift cylinders locked in the raised position until lowered. The directional valve diverts the fluid to the lower part of the lift cylinder, which causes the pressurized fluid to push against the piston enclosed within it.

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.

When the pistons are extended to the end of their stroke, or if the load is too heavy to be lined 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 fluid will continue to be diverted from the lift cylinder to the reservoir until the electrical power is interrupted.

Lowering A Load A load is lowered by depressing the side button on the controller while pushing forward. This moves the spool and opens a path for the trapped fluid to flow from the cylinder back to the reservoir.

Sheet 7: Hydraulic System Tilting A Load Tilt is accomplished by moving the Tilt Lever, which directs oil to either end of the tilt cylinder. Oil pressure builds up to overcome the load resistance, and the piston moves within the cylinder depending upon which way the oil is directed by the valve spool. When the end of the stroke is reached or the load is too heavy to move, the system relief spring pressure is overcome and opens a path to the tank. This prevents damage to the system.

MAINTENANCE PROCEDURES The hydraulic pump and motor assemblies are mechanically joined together as a compact unit combining pump and motor as a single assembly. The pump is located below the motor and is held in place by four bolts.

Hydraulic unit servicing is best performed by cleaning the unit of dirt and grease before removing the unit from the truck to a clean work area. Brush replacement, however, can be easily performed on the truck. (See Section 2.)

There are six basic remove-and-replace procedures to be followed when servicing the hydraulic system. These procedures are: • • • • • •

Remove and Replace the Hydraulic Unit Disassemble and Assemble the Hydraulic Pump Adjust Relief Valve Setting Remove and Replace Control Valve Assembly Remove and Replace the Lift Cylinders Disassemble and Assemble the Lift Cylinders

Refer to the drawings in this section when performing the pro-cedures listed above, and the General Truck & Lubrication section when checking, adding, or replacing fluid, and when removing and cleaning the breather.

Remove and Replace the Hydraulic Unit 1.

Open cover to expose hydraulic unit, and disconnect battery.

2.

Tag all wires to identify location.

3.

Loosen and remove wires from the unit.

4.

Remove, drain and cap hydraulic hoses.

5.

Loosen and remove the mounting bolts securing the unit to the truck. Support the unit as the bolts are removed.

6.

Reverse the procedure when reinstalling the unit. Tighten mounting bolts to proper torque value.

Figure 7-1—Hydraulic Pump ITEM DESCRIPTION 1.

2.

3.

4.

Screw—12 Point Needle Bearing Gear Gear Spacer

Sheet 7: Hydraulic System 5. Woodruff Key 6. Snap Ring 7. Ball Bearing 8. Shim 9. Oil Seal 10. Snap Ring 11. Drive Shaft 12. Dowel Pin 13. Idler Shaft & Gear Assembly 14. Gasket .0010"—Amber Gasket .0075"—Translucent DISASSEMBLE AND ASSEMBLE THE HYDRAULIC PUMP Disassembly: See Figure 7-1.

1.

Remove hydraulic unit from the truck (see above).

2.

Carefully separate the motor from the hydraulic pump, and set aside the coupler unit and motor.

3.

Clean outside of pump thoroughly, and punch or scribe housing for ease in reassembly. Also note and record posi-tion of the outlet (cover) port with respect to the inlet (body) port.

4.

Remove eight 12-point screws (1) from pump body, separate halves of pump.

5.

Remove idler shaft and gear (13).

6.

Remove the snap ring (10) from the drive shaft (11) and tap out the gear (3), shaft, bearing (2) and seal (9).

7.

Inspect all parts for wear or damage, and replace defective parts.

Reassembly: 8.

Reverse the above for reassembly. Use a new seal and gasket (14) between body halves

9.

Reassemble pump to motor, using a liberal amount of grease in the coupler and cavity.

Relief Valve Adjustment (See Figure 7-2) 1.

Clean exterior of valve to remove any contaminants.

2.

Remove pressure hose from fitting (2 in Figure 7-3) and put a "T" into the line that will accept a 3000 lb. gauge.

3.

Raise mast to end of its stroke and hold it there while reading the maximum system pressure with the gauge. Do not locate gauge near your face; if unusually high pressure is present, the glass may shatter.

4.

If pressure is in excess of 2000 p. s. i., lower mast and move handle back and forth to bleed pressure from the valve.

5.

Remove relief valve (4 in Figure 7-2), and while holding it in brass protective jaws of a vise, carefully remove screw, washers, spring, and plunger, while noting their relative posi-tions. If pressure is too high, add washers one at a time until the correct pressure of 2000 p. s. i. is obtained. If pressure is too low remove washers or replace springs if they are broken.

Caution must be exercised not to introduce dirt into the system, or to raise the pressure any higher than the 2000 p. s. i. recommended. Note each .006 (thousands) thickness of shim removed will raise the pressure approximately 100 p. s. i.

CONTROL VALVE REMOVAL (See Figure 7-2.)

1.

Disconnect and remove battery.

2.

Remove hoses from valve.

3.

Remove yoke pins from spool ends.

4.

Remove valve mounting bolts.

5.

Place valve on a clean workbench for disassembly.

Sheet 7: Hydraulic System DISASSEMBLY OF CONTROL VALVE Refer to Figure 7-2, Control Valve.

1.

During disassembly, particular attention should be given to identification of parts for reassembly. Spools are selectively fitted to valve bodies and must be returned to the same bodies from which they were removed. Valve sections must be reassembled in the same order.

2.

Plug holes and clean outside of valve before disassembly and repair.

3.

Remove the four tie studs (7) and nuts (8) and separate the valve sections. Be careful not to destroy or lose spacers if used.

4.

Remove the two screws (12) that secure the spool retainer end cap (13) and remove. If the cap has a detent assembly, unscrew the detent plug and remove the spring and piston. Remove the "O" ring from the cap.

5.

Operating Spools (17)—Slide the spool out of its bore and remove the "O" rings from the groove in the spool and from the valve body around the spool bore. Do not remove the centering spring (15), retainers, or the spool extension (18) unless it is necessary to replace them.

6.

Check Valve—Grip the stem of the check valve plug (11) with pliers and pull it out of the valve body. Remove the "O" ring and back-up ring. Remove the spring (10) and ball (9) from the valve body.

7.

Relief Valve Sub-Assembly—Unscrew the plug (1) that retains the relief valve and remove the "O" ring from the plug.

Remove the spring (3) and the relief valve (4) sub-assembly.

8.

Valve Body—remove the plug and "O" ring from the block-ed cylinder port on models with a single-acting spool. If the alternate discharge port is plugged, it is not necessary to remove the plug unless the body is to be replaced.

Figure 7-2—Three Spool Control Valve ITEM

DESCRIPTION

Sheet 7: Hydraulic System 1. Plug 2. Seal Kit 3. Spring 4. Relief Valve Cartridge (set at 2000 p. s. i.)

5. Shim 6. Outlet Section Assembly (Hoist) 7. Tie Stud (Bolt) 8. Hex Nut 9. Ball 10. Spring 11. Plug 12. Screw 13. Retainer 14. Sleeve 15. Centering Spring 16. "C" Washer 17. Spool 18. Cam 19. Bracket, Single Switch 20. Switch 21. "O" Ring 22. Plug 23. Inlet Section Assembly (Auxiliary) 24. Center Section Assembly (Tilt) ASSEMBLY OF CONTROL VALVE 1.

Discard all old seals. Wash all parts in a clean mineral oil solvent, and place them on a clean surface for inspection.

2.

Carefully remove burrs by light stoning or tapping. Be cer-tain there is no paint or burring on mating surfaces or valve bodies.

3.

Inspect the valve spools and bores for burrs and scoring. If scoring is not deep enough to cause objectionable leakage, the surfaces can be stoned or polished with crocus cloth. If scoring is excessive, the valve body and spool must be replaced.

Check the valve spool for freedom of move-ment in the bore.

4.

Check the relief valve for smooth movement in its bore. The valve should move from its own weight.

NOTE: Coat all parts with clean hydraulic oil to facilitate assembly and provide initial lubrication. Petroleum jelly can be used to hold seal rings in place on assembly.

5.

Valve Body—On models with single-acting spool, install the "O" ring on the port plug and plug the appropriate cylinder port. Tighten the plug securely but DO NOT over-tighten.

6.

Relief Valve—Install the "O" ring on the relief valve plug (1). Place the relief valve assembly (4) in its bore, hex nut end up. Install the spring and plug and tighten the plug securely but DO NOT over-tighten.

7.

Check Valve—Install a new back-up ring and "O" ring on the check valve plug (11 ) with the "O" ring toward the spring and ball (9). Place the ball and spring in the body and install the plug. Be sure the hole in the plug lines up with the stud hole in the body. Check valves are not used in "B" spool sections.

8.

Operating Spool—If the centering spring (15) was removed, install the spring and retainers on the spool. Place the "O" ring in the groove around the spool bore and install the "O" ring on the spool. Install the spool in the bore.

9.

Retainer (13—End Cap)—Install the "O" ring in the end cap groove, and install the cap and attaching screws. Torque the screws securely. On models with detents, grease all the detent parts. Install the end cap and check for proper spool extension alignment. Install the piston, spring and plug. Be sure to screw the plug in all the way.

10. Assembly of Unit—IMPORTANT: Make sure all mating sur-faces of valve bodies are free of burrs and paint.

Install seal rings and the seal ring retainer in the grooves in the body of each inlet and center section. Use petroleum jelly to hold the seals in place. Carefully place the sections together in the same order in which they were removed. Coat the stud threads with "Loctite" or similar sealant, and install the studs. Tighten the nuts to 15 foot pounds torque.

HYDRAULIC TANK—REMOVAL INSTALLATION

Sheet 7: Hydraulic System 1.

Disconnect battery.

2.

Remove Control Compartment Cover.

3.

Drain hydraulic tank into a suitable container.

4.

Tag and disconnect all hydraulic hoses at tank.

5.

Remove screws and washers securing hydraulic tank to frame.

6.

Remove hydraulic tank assembly.

7.

Reverse above to install, using a new filter and hydraulic oil, and a clean breather.

TANK INSPECTION a.

Drain and flush tank with clean hydraulic oil.

b.

Inspect tank for physical damage such as dents, scrapes, or gouges that may dangerously weaken the tank and make it unsafe for use.

c.

Replace tank when leaking beyond repair. Use the utmost precaution when using a flame around tank. Be certain tank has been removed, is well ventilated, and that there are no fumes.

NOTE: For LIFT CYLINDER MAINTENANCE, see Hi-Vis Mast Publication 1414.

TROUBLESHOOTING—HYDRAULIC CONTROL VALVE

Sheet 7: Hydraulic System TROUBLESHOOTING—HYDRAULIC PUMP

Sheet 7: Hydraulic System

Figure 7-3—Hydraulic System ITEM DESCRIPTION 1 2

Pressure Hose Elbow Fitting

Sheet 4: Load Wheel Brake Systems

LOAD WHEEL & BRAKE SYSTEMS

Figure 4-1—Load Wheel Assembly DESCRIPTION Tire & Wheel Assembly Tire Hub & Brake Drum Hydraulic Brake Assembly Brake & Axle Hex. Hd. Screw 5/8--11x1-1/2" Grade 5 Special Washer 7. Bearing Assembly—Inner 8. Soc. Hd. Screw 7/16--20x1" Hardened Washer 7/16" 9. Soc. Hd. Screw 518--11x1-3/4" Special Washer 10. Dust Shield 11. Bearing Assembly—Outer 12. Slotted Hex Nut 1-1/8"-12 12A. Cotter Pin 3/16-x2" 13. Hub Cap 14. Hex Hd. Screw 5/16--18x1/2" Grade 5 Lockwasher 5/16"

ITEM 1.

2.

3.

4.

5.

6.

CAUTION: When removing the load wheel, should the bearing (7) stay on the axle, remove it and install it into the wheel before reassembly. Failure to do so may result in damage to the oil seal.

REMOVAL OF LOAD WHEEL a.

Remove hub cap screws (14)

b.

Remove cotter pin (12a).

Sheet 4: Load Wheel Brake Systems c.

Remove nut (12).

d.

Rock wheel side-to-side, and remove outer bearing.

e.

Slide wheel off carefully. If inner bearing stays on shaft, damage to the oil seal may occur when wheel is replaced.

REPLACE LOAD WHEEL a.

Clean and inspect both bearings; replace if necessary.

b.

Repack both bearings using clean grease.

c.

Install inner (rear) bearing into wheel and slide wheel onto shaft.

d.

Apply additional grease to shaft.

e.

Push outer bearing into wheel.

f.

Replace nut and tighten securely to seat both bearings. Then back off slightly to align the hole in the nut with the hole in the axle shaft.

g.

Install cotter pin and bend ends over to lock in place.

h.

Reinstall dust shield.

NOTE: It is important to back nut off after tightening, or early failure will occur.

MOUNTING OF PRESSED-ON TIRES The base bands of all pressed-on tires are designed to be slightly smaller in circumference than the circumference of the wheel on which they are mounted. This difference is necessary to ensure that the tire remains on the wheel. Because of this, a hydraulic press is required to force the base band to stretch over the wheel. To ease the pressing of the tire over the wheel, the inside edges of the base band are tapered or rolled to act as a guide.

One or two pressing rings can be used for mounting these tires (See Figure 4-2). The solid ring is used as the base ring and it should be slightly smaller in diameter than the wheel. The split ring is not necessary but desirable to start the breakaway of the tire from the wheel.

The solid ring is placed in the hydraulic press and the wheel is centered over it.

It is suggested the split ring be used to start the removal of the old tire (See Figure 4-3). If the edges of the wheel are scored or damaged such that it would interfere with the tire mounting, the roughened edges should be ground off. Failure to do so could result in off-center or other mounting difficulties, or possible base band damage to the new tire.

Sheet 4: Load Wheel Brake Systems

Figure 4-2

Figure 4-3 BRAKES: GENERAL DESCRIPTION The ESC has two braking systems—the service brakes and the parking brakes.

The service brake system is hydraulically operated, with bonded shoe-type brakes in each load wheel activated by the operator's foot pedal.

The parking brake consists of a drum brake assembly mounted on top of the drive motor, and activated by a cable to a pedal at the left of the operator's compartment. Because the pedal must be depressed to release the parking brake, it is also known as a "dead-man brake. " Both of these brake systems have "micro" switches mounted on their respective linkages. The service brake switch (mounted on the master cylinder linkage) will cut out the SCR drive control. The "dead-man" switch connected to the parking brake pedal will interrupt the SCR control circuit and power steer circuit until the operator stands on the pedal and thus releases the brake.

SERVICE (WHEEL) BRAKE ASSEMBLY Inspection & Service (See Figure 4-4) DISASSEMBLY

Sheet 4: Load Wheel Brake Systems 1.

Remove load wheel assembly.

2.

Disconnect the shoe-to-shoe spring (9) from both shoes.

3.

Disconnect the red shoe hold-down spring (4) from each shoe, and then remove the shoes as an assembly from the support plate (1).

4.

Remove the blue shoe retainer spring (5) from the bottom of the two shoes, and separate the shoes.

5.

Remove the boots (11) from each end of the wheel cylinder. Then remove the pistons, cups and spring from the wheel cylinder bore.

Wheel Cylinder Inspection & Service 1.

Remove 2 screws and wheel cylinder from support plate.

2.

Wash and thoroughly clean inside of cylinder. Black stains, caused by cylinder cup, will do no harm.

3.

A cylinder hone may be used to remove minor marks; replace cylinder when scored or corroded.

4.

Remove all dust and grit by flushing cylinder with alcohol; wipe dry and clean again. Dry with compressed air, then flush with clean new brake fluid.

5.

Boots and piston cups must be replaced when reconditioning cylinder.

6.

Dip all parts in clean new brake fluid.

REASSEMBLY OF SERVICE BRAKES 1.

Loosen the nut (6) on each shoe adjusting eccentric (8), and turn each eccentric so that the low side is outward (toward the brake shoe (3) when installed).

2.

Reassemble the wheel cylinder (10).

3.

Assemble the blue shoe retainer spring (5) to the hole in the bottom of each shoe web.

4.

Position the shoes on the support plate, and secure in place with the red shoe hold-down springs (4).

5.

Be sure that upper end of each shoe web is properly posi-tioned in the wheel cylinder, and install the shoe-to-shoe spring (9) between the shoes.

NOTE: Adjustment is obtained by rotating each shoe-adjusting eccentric to move each shoe outward so that it contacts the rotating drum, and then backing off the eccentric so that there is no drag. The locknut (6) should be tightened so it takes 50 to 150 inch Ibs. of torque to revolve the eccentric bolt. Apply Loctite to the locknut to prevent loosening.

6.

Replace load wheel assembly.

MASTER CYLINDER—REMOVAL AND INSTALLATION (See Figure 4-5) a.

Disconnect battery.

b.

Disconnect brake line at master cylinder.

c.

Straighten and remove cotter pin and pin securing rod end to brake pedal weldment.

Sheet 4: Load Wheel Brake Systems

Figure 4-4—Service Brake ASSEMBLY TOOLS While not required, two tools that will save considerable time are: a. Standard brake spring pliers b. Brake resetting gauge ITEM DESCRIPTION 1. Support Plate 2. Shoe 3. Lining 4. Spring (red) 5. Spring (blue) 6. Hex Locknut 7. Spring Washer (2) 8. Bolt (Eccentric) 9. Spring 10. Cylinder Assembly 11. Piston Seals 12. Bleeder Screw 13. Brass Seat Do not remove for adjusting; if moved, see NOTE above.

Sheet 4: Load Wheel Brake Systems

Figure 4-5—Master Cylinder ITEM DESCRIPTION 1.

2.

3.

4.

5.

6.

7.

Boot (Filler Cap) Push Rod Assembly Piston Cup—Piston Spring Assembly Check Valve Assembly Gasket

d.

Remove screws, lockwashers and hex nuts secur-ing the master cylinder to truck frame.

e.

Remove master cylinder. Move to suitable work area.

f.

Reverse above to install. Bleed brakes and fill reservoir to proper level.

g.

Readjust pedal according to Service Brake Pedal Adjustment on page 4-5.

DISASSEMBLY a.

Clean outside of cylinder thoroughly.

b.

Remove filler cap (boot) and empty fluid from cylinder.

c.

Remove rubber boot and push rod.

d.

Remove lock wire, stop plate and piston.

e.

Remove piston cup, return spring and check valve assembly.

f.

Remove outlet fitting bolt, gasket and fitting.

BLEEDING BRAKES

Sheet 4: Load Wheel Brake Systems Bleeding the hydraulic brake system is necessary whenever fluid level in master cylinder has been permitted to get too low, or when any part of hydraulic system has been disconnected or replaced. Air in the system impairs braking efficiency.

NOTE: Only new, clean and genuine hydraulic brake fluid must be used. a.

Clean dirt from around master cylinder filler cap (boot), then remove cap. Fill reservoir if necessary and maintain fluid in reservoir during bleeding operation. Fluid must be within/ inch of filler opening.

b.

Bleed one wheel cylinder at a time, starting with the one farthest from master cylinder. In order to make sure all air is expelled from system, attach a piece of hose to bleeder valve opening and submerge the loose end of hose in a clean glass container of brake fluid.

c.

Open bleeder valve and press brake pedal slowly through half of its travel. Allow pedal to return to its released position, after which it may again be depressed until fluid runs out of bleeder hose in a continuous stream without air bubbles. Close valve and repeat on remaining cylinder.

SERVICE BRAKE PEDAL ADJUSTMENT 1.

2.

3.

To set pedal height: a.

Remove yoke pin (1) from rod yoke (8) at pedal lever, and push the rod assembly aside.

b.

Loosen pedal height adjusting set screw jam nut (2)

c.

Turn set screw (3) to position pedal 2-3/8" to 2-5/8" (2.4/2.6 inches) above floor plate.

d.

Tighten set screw jam nut.

e.

Replace rod yoke and pin in pedal lever.

To adjust pedal return spring length: a.

Loosen locknut on spring anchor eyebolt (4).

b.

Turn lower hex nut (5) until spring length is 6-7/8" to 7" (6.9/7.1 inches) end-to-end.

c.

Tighten locknut.

To adjust pedal rod assembly yoke end:

Important: The rod length must be set with the pedal in its up (brake released) position, and the bellcrank (11) applying no force on the master cylinder push-rod (6).

4.

a.

Remove yoke pin (1 ) from yoke (8) and pedal lever (9)

b.

Loosen yoke jam nut (7) and back off several turns.

c.

Turn the yoke (8) on the rod until the pin hole aligns with the hole in the brake pedal lever (9). Install the yoke pin (1) and its cotter pin.

d.

Tighten the yoke jam nut (7).

Check the switch above the brake master cylinder (10). The switch must close when the brake pedal is fully released and must open when the pedal is depressed. Adjust the vertical position of the switch if necessary.

Sheet 4: Load Wheel Brake Systems

Figure 4-6—Service Brake Pedal Assembly ITEM DESCRIPTION 1. Yoke Pin 2. Hex Jam Nut 3. Set Screw 4. Eyebolt Locknut 5. Eyebolt Hexnut 6. Master Cylinder Push-rod 7. Yoke Jam Nut 8. Rod Yoke 9. Pedal Lever 10. Micro Switch 11. Bellcrank

Sheet 4: Load Wheel Brake Systems

Figure 4-7—Parking Brake ITEM

DESCRIPTION

1. Locknut 2. Cam Washer 3. Cam Assembly 4. Cam Arm (not shown) 5. Hex nuts (3) 6. Shoe Washers (2) 7. Mounting Plate Assembly 8. Shoe & Lining Assembly (2) 9. Springs (2) 10. Washer 11. Actuator Arms (2) 12. Drive Blocks (2) 13. Drum and hub assembly PARKING BRAKE ASSEMBLY—Inspection & Service (See Figure 4-7)

Assembly

Disassembly 1.

Remove hex nut holding brake drum (10 in Figure 4-8).

2.

Remove hex nut securing ball joint to connecting rod (11, 12 & 13 in Figure 4-8).

3.

Lift drum and hub (13 above) from assembly.

4.

Remove 2 springs (9) and the hex nuts (5) and shoe washers (6), and lift off shoe assemblies (8).

5.

Replace with factory-approved linings when worn.

6.

To remove brake assembly from the Drive Motor: a.

Remove hex nut (1) for access;

Sheet 4: Load Wheel Brake Systems b.

Remove 4 hex bolts that secure the mounting plate (7) to motor.

Assembly 1.

Place brake assembly on Drive Motor and reinstall 4 mount-ing bolts.

2.

Replace the cam assembly locknut (1), being careful not to over-tighten (torque to 18-23 inch-lbs.).

3.

Replace brake shoes, springs, shoe washers and hex nuts.

4.

CAUTION: Torque hex nuts to 30-40 inch-lbs. maximum; over-tightening will make future brake rebuilding very difficult.

5.

Replace the brake drum and hub with the hex nut, and adjust the brake using the procedure that follows.

Sheet 4: Load Wheel Brake Systems ITEM DESCRIPTION 1. Locknut 2. Bronze Screw 3. Cable Yoke 4. Bellcrank 5. Stop screw 6. Eyebolt Hex Nuts 7. Micro Switch 8. Pedal Spring 9. Mounting Bracket 10. Slotted Hex Nut 11. Locknut 12. Ball Joint 13. Connecting Rod 14. Spring 15. Brake Drum PARKING (DEAD-MAN) BRAKE ADJUSTMENT PROCEDURE 1.

Loosen locknut (1) on bronze adjusting screw (2), and back away from contact plate.

2.

Depress pedal to full brake off position and secure it in this position.

3.

Adjust yoke (3) on upper end of cable so that the lever on the bellerank (4) is horizontal within 1/2, degree.

4.

Adjust pedal "up" stop screw (5) to obtain a gap of 5/32 (.15/ 17) in.

5.

Adjust pedal return spring (8) length to 7-314 (7.3817.75) in. by moving nuts (6) on spring anchor eyebolt.

6.

Turn bronze screw (2) until rear of ball joint (12) on brake release rod assembly (13) is 1/16 (.04/.06) in. from inside of mounting bracket (9).

7.

Adjust spring (14) to 1-3/8" (1.38 t.03) in compressed length.

8.

Release pedal to brake "on" position.

9.

Adjust micro-switch (7) so that brake releases before the switch closes, and opens before the brakes drag. The pedal must be a minimum of 3/4 (.75) in. above the floor plate mat when the switch closes. When the pedal is up, the bronze screw (2) should not touch its contact plate.

BRAKE SYSTEM TROUBLESHOOTING

Sheet 4: Load Wheel Brake Systems

Sheet 6: Mast Assembly

MAST ASSEMBLY Refer to Service Publication ITD 1414 for maintenance information on the mast assembly.

Sheet 5: Steer System

STEER SYSTEM GENERAL INFORMATION Power steering is standard on the ESC and manual steering is available as an option.

Power steering is accomplished through a torque generator that is shaft-driven by the steer handle and column. This unit is a power-assist unit: an initial effort by the operator in turning the steer handle opens ports inside the control valve; hydraulic fluid under pressure then flows through the valve to assist in the steering effort.

The output shaft of the torque generator transmits power through a gear system to a chain that traverses beneath the drive motor sprocket and shaft sprocket. The drive unit and motor pivot in the frame in a ball bearing assembly. This assembly can be adjusted to compensate for wear and steer effort. This unit should be lubricated before attempting any adjustments.

The manual steer is identical except that the torque generator is replaced with a simple shaft assembly. Steer effort for manual steering should not exceed 20 Ft. Lbs. If steer effort does exceed 20 Ft. Lbs. , the following items should be checked: 1.

Lack of lubrication of steer gears and chain.

2.

Drive unit bearings not lubricated, or out of adjustment.

3.

Steer chains too tight.

4.

Steer shafts not parallel, causing a binding condition at the steer gears.

STEERING ADJUSTMENTS See Section 3 (Drive Unit) for instructions on drive unit ring bear-ing adjustment.

The steering chain should be adjusted to maintain 1/16 to 3/16 of an inch deflection while applying a 5 lb. force on the approximate center of the chain (10) between the motor sprocket (9) and the steer sprocket (8). (See figure 5-1.)

To adjust chain tension and to align steer shafts (6, 7), it is necessary to slightly loosen the eight steering assembly mounting nuts (11), and move the shaft support brackets in their slots.

Sheet 5: Steer System

Figure 5-1—Power Steering Assembly ITEM DESCRIPTION 1. Steer Knob 2. Steer Handle 3. Upper Pin and Collar 4. Torque Generator (or Shaft) 5. Lower Pin and Collar 6. Gear and Shaft Assembly (Upper) 7. Gear and Shaft Assembly (Lower) 8. Sprocket Assembly 9. Drive Motor and Sprocket Assembly 10. Chain Center-point 11. Assembly Mount Nuts

TORQUE GENERATOR The input and output shafts of the torque generator are directly in line, and the entire unit is less than four times the diameter of shafts commonly used for these purposes. The combination of control and power elements in a single unit provides an economical and trouble-free power steering unit.

Control valving is open center, and the hydraulic fluid circulates through the unit back to the reservoir at very low pressure when the system is not being steered. Manual pressure to the input shaft deflects the internal porting to direct flow from the power source to the gerotor section, producing the powered output.

The power output shaft is connected to gears that are identical to those used for manual steering.

Relative deflection of the input and output shafts is limited mechanically within the unit so that manual emergency steer-ing is

Sheet 5: Steer System still possible in the event of power loss.

For proper operation it is recommended that the unit be installed so that no radial load or thrust load is applied to either the input or output shafts. Misalignment of shafts can cause binding.

TORQUE GENERATOR REMOVAL a.

Remove motor compartment cover.

b.

Remove cowl support plate mounting screws.

c.

Remove hose manifold (2 screws), and cover it to keep dirt out.

d.

Grasp steer handle (2) and pull straight up. The gear and shaft will probably come out with the handle; if not do not lose the Woodruff Key.

e.

Support shaft (6) and drive the roll pins (3, 5) out at each end. The collars can now be slid off the torque generator and Woodruff Keys.

f.

Replace with a new or repaired unit, and reverse disassembly process to reassemble.

DISASSEMBLY Cleanliness is extremely important when repairing a steering con-trol unit. Work in a clean area. Before disconnecting the lines, clean port area of unit thoroughly. Use a wire brush to remove foreign material and debris from around exterior joints of the unit.

TOOLS REQUIRED FOR DISASSEMBLY AND REASSEMBLY •

12 point socket

•

Breaker bar wrench

•

Torque wrench (285 inch pound capacity)

•

Plastic hammer or rubber hammer

•

Needle-nose pliers

Figure 5-2—Torque Generator If a complete tear-down and reassembly of the unit is necessary, clean all paint and surface contamination from the unit at points of separation. This is extremely important at the ports and the power end of the unit, so that no paint flakes or particles will

Sheet 5: Steer System enter these closely fitted parts as they are being reassembled.

To clean the unit adequately, first plug all ports, then wire brush around the gerotor (25) area and rinse and blow away all surface contamination before any disassembly is begun.

Do not use shop cloths or cotton waste to wipe or clean the parts. The lint deposited by these can disrupt function or cause leaks. The clean inside surface of a corrugated container is frequently a very adequate assembly surface.

Assembly is generally easier and more satisfactory with clean dry parts. After parts are rinsed clean in solvent, they may be blown dry with an air hose or placed on a clean paper towel to drain and air dry.

If parts are thus prepared as they are removed, they will be ready for reassembly by the time they are needed.

STEERING SYSTEM NOTE: The following tool isn't necessary for disassembly and reassembly, but is extremely helpful.

ALIGNMENT TOOL (Part No. 600057) This tool is available by contacting: Eaton Corporation Fluid Power Operations Minneapolis Division 15151 Highway 5 Eden Prairie, MN 55344

Figure 5-3—Torque Generator (Exploded View) ITEM DESCRIPTION 1. Point Cap Screw 1/4--20x1" 2. Control End Cap 3. "O" ring 4. Quad Ring 5. Washer—Seals 6. Port Block Kit 7. Soc. Hd. Screw 5/16--18x1 8. Port Block 9. "O" Ring 10. Matched Assembly—Control End 11. Housing—Control End

Sheet 5: Steer System 12. Spool 13. Spring—Centering 14. Pin—Centering 15. Sleeve—Control 16. Drive—Control End 17. 12 Point Cap Screw 1/4"--20x2-3/8" 18. Power End Assembly 19. Housing—Power End 20. Quad Ring 21. Washer—Seal 22. Shaft—Power End 23. Drive—Power End 24. Plate 25. Gerotor (.520" Thick) * Seal Kit

DISASSEMBLY OF TORQUE GENERATOR In the following step-by-step disassembly and reassembly pro-cedure, there are references to the control end and the power end of the torque generator. The end of the unit that is attached to the tiller is the control end. The output side that is connected to the reduction gears and chains is the power end. In reference to Figure 5-3, items 1 through 16 would be part of the control end, and items 17 through 25 would be the power end of the unit.

STEP 1 —Remove seven 1/4" bolts (17) from power end housing (19). Remove power end cap and shaft (22).

Figure 5-4 STEP 2—Remove splined drive (23)

Figure 5-5 STEER SYSTEM

Sheet 5: Steer System STEP 3—Remove separator plate (24).

Figure 5-6 STEP 4—Remove gerotor section (25).

Figure 5-7 STEP 5—Remove control end drive shaft (16)

Figure 5-8 STEP 6—Remove separator plate (24).

Figure 5-9

Sheet 5: Steer System STEP 7—Remove four 1/4" screws (1) from control end cap (11) and slide cap off of shaft (12).

Figure 5-10 STEP 8 Slide spool and sleeve assembly (10) out of control end housing.

NOTE: Pull spool out of housing with an even sliding motion. Twist spool while pulling. It is important to pull the spool out from the shaft end as shown in the photo. If the spool will not come out, it is possible that the spool and sleeve moved towards the power end and the centering pin (14) became lodged in the groove machined into the housing. If so, reach into the power end of the housing with a needle nose pliers and shift the centering pin back and forth until the spool is free to slide out of the housing.

Figure 5-11 STEPS 9—Remove the centering pin (14) that holds the spool and sleeve together.

Figure 5-12 STEP 10—Separate the spool (12) and sleeve (15). Do not remove the centering springs (13) from the spool unless necessary.

If it is necessary to remove the springs, a special align-ment tool, part number 600057, is extremely helpful for reassembly. This tool is available from Eaton Corporation

Sheet 5: Steer System

Figure 5-13 REASSEMBLY Before reassembly, clean all parts thoroughly and lightly oil to assist in reassembly. Do not handle the spool and sleeve too long or body heat will expand the metal so that reassembly will be difficult.

Reassembly is basically the same as disassembly except for the following important steps.

STEP 11—Replace the quad ring, seal washer and "O" ring (3, 4, 5) in the control end cap with new parts before assembly.

Figure 5-14 STEP 12—Make sure that the spline end of the drive shaft rests above the separator plate or proper alignment will not be possible.

Figure 5-15 STEER SYSTEM STEP 13—It is necessary to properly align the centering pin, control drive shaft, and gerotor section with respect to the main body during assembly. Failure to do so will cause the valve to be out of time, and the tiller, upon initial start up, will move by itself to one side and lock-up in that position.

Sheet 5: Steer System With the port side of the body facing as shown, align the centering pin and drive shaft in a parallel manner as indicated by lines B C, and D. The gerotor section should then be aligned so that the star valleys will also be parallel as indicated by line A. Also at the twelve o'clock position, one tooth of the gerotor will be centered in the valley of the outer ring.

Figure 5-16 STEP 14—Replace the quad ring and seal washer (20, 21) in the power end cap.

Figure 5-17 STEP 15—Torque all end cap bolts to 280 inch-pounds or 23 foot-pounds.

Sheet 5: Steer System

Figure 5-18

POWER STEER MOTOR—GENERAL The power steer motor is a permanent magnet type. Unlike conventional motors, it has permanent magnet pole pieces in place of field coils.

STEER PUMP AND MOTOR REMOVAL a.

Tilt mast all the way back, and place blocks under the fixed (stationary) sections; then tilt forward to raise front of truck.

b.

Raise forks, and block front of truck for safety. Front wheels should be approximately 12" off floor.

c.

Disconnect and remove battery and drip (support) plate.

d.

Remove inlet and outlet hoses on pump. Allow hoses to drain into an oil pan, and plug them to prevent contamination.

e.

Tag and remove both motor wires.

f.

Remove four motor mounting bolts from the assembly, and support it to prevent its falling.

g.

Lower pump and motor to floor and slide out for service.

h.

Reverse the procedure above for replacement, and check hydraulic oil level.

Sheet 5: Steer System

Figure 5-19—Steer Pump and Motor ITEM DESCRIPTION 1. Motor Assembly' * 2. Gasket 3. Coupling 4. Pump Assembly 5. Point Screw 5/16--18x3/4" Lockwasher 5/16" *See Section 2 (Electrical System) for Motor and Coupling Service information.

Figure 5-20—Power Steer Pump ITEM

DESCRIPTION

Sheet 5: Steer System 1.

2.

Screw—12 Point Gasket .0010"—Amber Gasket .0075"—Translucent 3. Needle Bearing 4. Snap Ring 5. Gear 6. Spacer—Gear 7. Steel Ball 8. Spring 9. Adjusting Screw 10. Copper Gasket 11. Cap Nut 12. Oil Seal 13. Key 14. Drive Shaft 15. Idler Shaft & Gear Assembly 16. Dowel Pin 17. Plug W/"O" Ring POWER STEER PUMP—DISASSEMBLY (Refer to Figure 5-20—Power Steer Pump) NOTE: Pump should never be disassembled (other than for leakage at oil seal) unless it is not working properly. Be certain motor and coupling are working properly before pump is disassembled. a.

Remove eight 12 point screws (1) holding pump halves together. Note position, and separate halves.

b.

Remove idler shaft and gear assembly (15). Remove drive shaft (14) and gear assembly.

c.

Check bearings and gears for signs of wear or galling. Replace when worn or damaged.

d.

Remove cap nut (11), gasket, adjusting screw, spring and spring and ball assembly. Note position of adjusting screw by counting the number of turns when removing to facilitate reassembly.

e.

It is always good policy to replace oil seal (12) whenever pump is disassembled.

POWER STEER PUMP—ASSEMBLY a.

Install a new oil seal and tap in place.

b.

Position bearings (3) in both halves (two in each half).

c.

Install a new gasket (2) on pump housing.

d.

Install drive shaft assembly (14) at oil seal end. Use ex-treme care when shaft is placed through oil seal.

e.

Install idler shaft and gear assembly.

f.

Position remaining half of housing. Install and tighten eight 12 point screws securing both halves of pump housing.

g.

Install spring and ball assembly, spring, adjusting screw, gasket and cap nut.

h.

Be certain pump drive shaft turns freely by hand when assembled.

RELIEF VALVE ADJUSTMENT—POWER STEER PUMP a.

Install pressure gauge into pump pressure line.

b.

Remove cap nut (11, Figure 5-20).

c.

Turn tiller to its fullest extent.

d.

Turn adjusting screw (9) until the gauge reads 400 p. s. i.

e.

Reinstall cap nut.

Sheet 9: User Support Information

USER SUPPORT INFORMATION Your investment in a Yale Industrial Truck is important to you and to your Yale Dealer. You measure the return on that investment through the performance of these trucks, and of the drivers who operate and the mechanics who service them safely and efficiently. The following information and programs are intended to help you to achieve your investment objectives:

SERVICE PARTS ORDERING INSTRUCTIONS HOW TO ORDER SERVICE PARTS In order to avoid delay and 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.

WHEN ORDERING PARTS Contact your authorized Yale Industrial Truck Dealer providing the following information: 1.

Your Purchase Order number.

2.

Complete invoicing and shipping address.

3.

Specify the method of shipment; otherwise the least expen-sive 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.

TECHNICIANS SERVICE PUBLICATIONS Maintenance Manual ITD-1432 This Maintenance Manual has been designed to assist every user to effectively maintain his Yale Industrial Truck in a safe and useful condition, with complete procedures for service and overhaul.

Service Parts Manual ITD-1421 The Service Parts Manual contains complete replacement parts identification, and is divided into major sections to correspond with this Maintenance Manual.

Operator's Manual—ITD-1428 Part No. 5195948-01 To provide instructions for safely operating and servicing Yale Industrial Trucks, each truck is equipped with an operator's manual. It describes various operating techniques and safety precautions to the operator. It contains a guide to safe maintenance practices and recommended schedules for maintenance. If the operator's manual is missing from any Yale Industrial Truck, it should be replaced. Replacement copies are available for a nominal fee from your Yale Dealer.

OPERATOR TRAINING Yale "Handle With Care" program helps industrial truck users increase materials handling productivity and safety through proper lift truck operation training and motivation. Motion pictures, supporting manuals and exercises instruct users in safe, skillful operating techniques.

MAINTENANCE SAFETY TRAINING Yale "Service With Care" program does for lift truck maintenance personnel what "Handle With Care" does for operators—it provides safety motivation training. It also consists of motion pictures and supporting safety-oriented literature.

SERVICE TRAINING COURSES User and Yale 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 mechanical,

Sheet 9: User Support Information electric and electronic subjects are offered at published tuition rates. Courses are available at user and Dealer facilities in addition to regularly scheduled courses conducted at Yale Corporate Headquarters in Flemington, New Jersey.

SERVICE TRAINING MATERIAL Your own service training efforts are supported through a com-plete line of Yale Service Training materials. An Index is available from your Yale Dealer that lists textbooks, audio-visual programs, films and their costs—to provide your Trainer with everything necessary to conduct service training for your organization. Text-books available are: Stl-1347 Pulsomatic SCR Stl-1250 Tune-up & LPG Stl-1207 General Electric SCR Stl-1212 Transmission Stl-1209 Hydraulics For additional information or assistance in obtaining these user support publications and programs, contact your Yale Dealer or the Yale Materials Handling Corporation, Routes 523 & 31, Flemington, New Jersey 08822.

SAFETY AND OPERATIONAL CHECK LIST A "Daily Check List" similar to that shown in the illustration 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 by ordering Form #E162-6418 from your local Yale Dealer for a nominal fee.

Sheet 9: User Support Information

1432 9/86 SUPPLEMENT

INTRODUCTION EV-100 SCR CONTROLS The G.E. EV-l 00 SCR control panel replaces the EV-1A and EV.1B panels. The EV-100 will be used in all 2,000 Lb. to 5,000 Lb. electric trucks with the exception of the ERC 060 HB model. The ERC 06-120 HB and the ERC 100-150 KB will continue to use the EV-1 C panel. Almost all of the operational characteristics, component test procedures card adjustments and troubleshooting procedures are exactly the same as the EV.1 controls.

However. following are some of the minor differences which you should be aware of when working on EV-100 equipped vehicles. .

—The EV-100 panel uses a reactor (inductive coil) instead of a transformer to charge the capacitor to a substantially higher voltage than battery voltage. The reactor is labeled T4-T3 on the wiring diagram and is connected between the capacitor (IC) and the 5 Rec. — Four filters are use a on the EV-100 panel to protect against voltage spikes. They are labeled the 22 Rec. 25 Rec. 23 Fil and 24 Fil; and they protect the 2 Rec 5 Rec. Rec and 4 Rec respectively .

An MS-4 or 1A switch is not used to activate the 1A by-pass function within the control card,. The 1 A circuit is activated when the accelerator potentiometer voltage decreases to 0.5 volts or less. If the control, Panel is in thermal cutback. the 1A

Sheet 9: User Support Information function will be inhibited. On trucks equipped with Cableform accelerators. particularly in applications involving steep ramps, there may be problems with the accelerator voltage decreasing to less than 0.5 volts.. To overcome this problem and to get full power in 1 A to climb a ramp. a jumper wire should be inserted into the plug position opposite wire #45.. This will allow the 1 A switch in the accelerator box to be used as a parallel circuit around the accelerator potentometer to assure that the voltage at card terminal TB-1 decreases to less than 0.5 volts to activate the 1 A circuit.

The plugging seventy is related to the position of the accelerator potennometer. Thus if the truck is plugged when the accelerator is at minimal travel the plugging seventy will be slight. and if the accelerator is at the full speed position during plugging the plugging will be more severe.

Following are component identification. location and test procedures. card adjustment specifications and troubleshooting charts to assist in fault finding.

Component Test Specifications Following is a quick reference list of test specifications and illustrations of components use a on the GE EV-100 SCR control.

A volt-ohm meter equipping with R X 1 R X 1,000 and R x 10,000 scales is recommended for testing EV-l 00 components. The component Tester (5180968-31 ) is also recommended for testing most of these components. Refer to the test procedures that are supplied with the tester.

Capacitor 1.

2.

3.

4.

5.

Switch meter to highest resistance scale.

Attain meter leads to capacitor terminals.

Needle should deflect towards zero ohms and then rise to above 500.000 ohms.

Switch meter leads and meter should repeat action of step 3.

Should read infinity between either terminal and case.

SCR's 1.

2.

3.

4.

Meter—R x 1 0.000 Red lead on anode ( + ) Black lead on catnode ( - ) Meter should read more than 500.000 ohms Reverse leads of step 1 and reaching should be more than 500,000 ohms.

Meter on R x 1 Red lead on gate - Black lead on cathode Meter reading—10 to 80 ohms Reverse meter leads of step 3 and meter reading should be more than 5 ohms.

Sheet 9: User Support Information

NOTE: Disregard the + and - symbols molded into the plastic case. SCR is wired opposite to markings .

Reactor 0-1 ohms from T3 to T4 Choke Coil 0-1 ohms from T3 to T5

23 Filter 24 Fitter 1 2 3 4 5

22 Rec Snubber 25 Rec Snubber

Switch meter to highest resistance scale.

Attach meter leads to capacitor terminals.

Needle should deflect towards zero ohms and then rise to above 500,000 ohms.

Switch meter leads and meter should repeat action to step 3.

Should read infinity between either terminal and case.

Diodes 5-25 ohms pos. to neg.

Anode ( + ) Cathode ( - ) More than 500.000 ohms on the R x 10.000 scale from neg. to pos.

Sheet 9: User Support Information

Sensor 0-1 ohms (check from yellow to green wire at card plug terminals 3 and 4).

Thermoprotector 100-200 ohms at room temperature (check at gray and black leads at the card plug terminals 1 and 5).

Filter Junction Block Dotted Lines Show Which Terminals Are Connected Internally

Sheet 9: User Support Information

Three Individual Terminals Are Insulated Mounting Points NOTE. Black wire from capacitor (1C-2) passes through slot in case of junction block to reactor T-3 without making any electrical connections.

WIRING FOR EV100T SCR CONTROL

Sheet 9: User Support Information

NOTES: 1.

2.

3.

4.

Terminal TB1 Wire 29 TB2 Wire 15

ALL #22 TERMINALS MUST BE OF INSULATION GRIP TYPE TWIST GREEN AND YELLOW LEADS OF SHUNT SENSOR THEN TWIST WITH BROWN NEGATIVE LEADS THEN CONNECT TO DESIGNATED PLUG TERMINALS TWIST BLACK AND GRAY LEADS OF THERMAL PROTECTOR THEN CONNECT TO DESIGNATED PLUG TERMINALS Function of EV.100 Card Terminal Description Condition Accelerator Potentiameter Key on and accelerator at creep speed input Key on and accelerator at top speed Accelerator and brake switch Key, seat, accelerator & brake switch closed input

Voltage 3.0-4.0 0.5-0.0 B.V.

Sheet 9: User Support Information TB3 Wire 2 TB4 Wire 10 TB5 Wire 6 TB6 Wire 8 PB1 PB2

Seat switch input

Key & seat closed

B.V.

Key switch input

Key closed

B.V.

Forward directional switch input Reverse directional switch input % on time output

Key, seat, start, brake and directional "F" switch closed.

Key, seat, start brake and directional "R" switch closed.

Creep speed Top speed No current 500 amps average motor current 1A closed, high speed All switches closed top SCR speed Potentiometer Voltage less than 0.5 V Not plugging mode Plugging mode

B.V.

PB3 PB4 PB5

Motor current sensor Output FW drive output Output to PMT driver 1A driver output

PB6

Plugging output

EV - 100 Control Card

B.V. 2.5 6.5 1.80 3.30 2.0 2.0 2.0 0.0 12.0

Sheet 9: User Support Information

CARD ADJUSTMENT PROCEDURE FOR EV-100 PANELS INTRODUCTION There are five standard potennometers on all EV-100 cards that can be adjusted to assure optimum performance or to compensate for applications on various size vehicles. These pots should be adjusted when installing a new or rebuilt card or if the truck is performing unsatisfactorily. The pots are located under a door on the top face to the carat The five pots are labeled Creep. C/A (Controlled Acceleration). C/L (Current Limit) 1A Time and Plugging. Some cards will have two additional pots if the card is used on trucks equipped with feld Weakening. They are labeled FWPU (Field Weakening Pick-Up) and FWDO (Field Weakening Dropout). Each pot can only be turned from 1 to 9. there are no multiple turn pots. Adjustment is simple since no special tools or test instruments are required. Following are brief descriptions of the function to each pot and the corresponding adjustment procedure.

Sheet 9: User Support Information

CREEP— The creep speed pot controls the rate of drive motor rotation when the start or MS-1 switch is first closed. Heavier vehicles will require a higher setting while lighter vehicles will require a lower setting. Setting the pot below 2 will prevent any drive wheel rotation.. Adjust the pot to achieve a satisfactory creep speed with the truck in Its normal operating condition.

C/A—CONTROLLED ACCELERATION— This pot determines how test the vehicle will accelerate to the top SCR speed when the accelerator activated to the full-on position. A setting of 9 is recommend for all Yale lift trucks.

C/L—CURRENT LIMIT— The current limit function of the card protects the SCR panel from excess loads when the truck is operating in the SCR range.

The current limit amperage is basically fixed by the design of the card however a small variation can be obtained by adjusting the C/L pot. A setting to 9 Is recommended for all Yale trucks.

1A TIME DELAY— This pot determines the time delay for closure to the 1 A contactor after the accelerator voltage drops below 0 5 volts Proper adjustment to this pot assures that the truck will at least accelerate for a few seconds in the SCR range before jumping into full speed when the 1A contactor closes. A setting of 3 will give a 1-1/2 second time delay which is the recommended minimum operation time In SCR range.

CARD ADJUSTMENT PROCEDURE FOR EV 100 PLUGGING— The plugging feature provides smooth reversal of the truck when the operator suddenly changes direction while in motion.

Adjustment to the pot will vary the distance the truck will travel before reversal when the directional switch is moved from one position to the other. Adjust the pot to obtain a minimum travel distance to 1-1/2 truck lengths.

FIELD WEAKENING PICK-UP— This pot controls the closing of the Field Weakening contactor. A setting of 9 will assure that this contactor will not close until the current load in the motor has dropped to a safe value such as when cruising in 1A speed.

FIELD WEAKENING DROPOUT— This feature will open (dropout) the Field Weakening contactor if there is a sudden increase in current draw while cruising such as when starting up a ramp. The truck will then revert back to normal 1A or SCR operation for full power capability. A setting. of 9 is recommended for this feature.

EY-100 Troubleshooting Guide Before troubleshooting the truck, observe the following precautions and preliminary checks: 1.

2.

Check battery specific gravity.

Check battery polarity.

Sheet 9: User Support Information 3.

4.

5.

Jack drive wheels off floor.

Check for weided contactors.

Visually inspect wiring, plug connections. switch operation and accelerator pot linkage.

The following troubleshooting guide contains eight Tables of common symptoms or malfunctions that can occur on an EV-l 00 controlled lift truck. Under each table are lists of procedures and components that would have to be checked to locate the source of the problem.

These are the main Tables or categories of symptoms that are common on the EV-l OO trucks.

Table 1 Directional Contactors Do Not Close No SCR, No 1A. Table 2 Dlrectlonal Contactors Close No SCR, No 1A. Table 3 Dlrectlonal Contactors Close Little or No Power, Low SCR Hum, No. 1A Table 4 Dlrectlonal Contactors Double Trip Table 5 Miscellaneous SCR Problems Table 6

Normal or Slow SCR Speed No 1A

Table 7

Mlsoperatlon of PMT Functions

Table 8 Miscellaneous Symptoms Table 1 Symptom—Directional Contactors Do Not Close, No SCR. No 1A

Sheet 9: User Support Information

Table 2 Symptom—Directional Contactors Close No SCR. No 1A Note: Items 1-4 can be quickly checked by manually closing the 1 A ancherner the forward or reverse contactor.

If truck does not run. check items 1-4. It truck does run. skip 1-4 a,,a check items 5-10.

Check: 1.

Main power fuse 2.

Motor armature and fields 3.

Contact tips 4.

Power wiring and sensor 5.

Accelerator (check output voltage at TB-1 which should be from 4 volt down to less than .5 volt).

6.

Rec (open or no gate signal from card) 7.

2 Rec (open or no gate signal from card) 8.

Control card Table 3 Symptom—Directional Contactors Close, Little Or No Power,Low SCR Hum, No 1A. Check: 1.

Accelerator pot

Sheet 9: User Support Information 2.

3.

4.

4 Rec (shorted) 2 Rec (shorted) 22 Rec (shorted)

Table 4 Symptom—Directlonal Contactors Double.Trip Check: 2.

3.

4 5.

6.

7 8.

1 5 Rec 2 Rec 25 Rec 22 Rec Capacitor 1C 1X choke coil (T5 to T3) Reactor (T3 - T4) Control card

Note: If all of the above Items check good. try inter-changing the positions of the 22 and 25 Rec. Table 5 Miscellaneous SCR Problems.

Symptom 1. Contactor close.

Reduced SCR Speed.

Abnormal high pitch SCR hum.

2. 2.Contactors close.

Full SCR Speed immediately with audible hum No PMT trip.

3. SCR speed higher than normal.

Current values uncontrollable with C/L pot.

4.

PMT trips contactors when accelerator is returned to SCR range from 1 A speed.

5.

One directional contactor closes.

SCR speed in that direction only.

Check a.

3 Rec (open) a. b.

Accelerator pot out of adjustment Faulty control card

a. b. a

Yellow or green sensor lead open Faulty control card A dropout too long because of bad 1 A diver bad 1 A coil or wrong coil Check voltage at TB-5 and TB 6 of card (also connections of TB terminal to card).

Should be battery voltage.

Check ohm value of directional coils. Should be approximately 25 ohms.

Check for battery voltage at terminal 3 or 4 of the PMTD when the appropriate switches are closed.

Replace PMTD if all of the above check good.

Check Directional Switch.

Make sure both sides of the normally open contact tips of the nonfunctioning directional contact are closed properly when the coil is energized (see note) Make sure that the normally closed tips of the functioning contactor are making good contact (see note)

a. b. c.

6.

Both directional contactors operate normally.

SCR speed in one direction only.

d. e. a.

b.

Note: When the forward directional contactor is closed. motor contact flows through the normally open tips of the forward contactor. through the field windings and then through the normally closed tips of the reverse contactor to reach the armature. The opposite is true when the reverse contactor is closed.

7.

90th contactors close at the same time.

No SCR speed.

Table 6 Symptom—Normal Or Slow SCR Speed. No. 1A.

a. b.

Direction switches Hour meter diodes

Sheet 9: User Support Information Check voltage from PB-S to negative (should be approximately 2V)

All switches must be activated and accelerator must be depressed to the full speed position.

A.

If voltage is 7~8V. check: 1.

Continuity of wire 34 from PB-5 to terminal 1 of the 1 AD 2.

Continuity of negative wire to terminal 2 of the 1 AD 3.

If both wires 34 and neg. are good. replace the 1 AD

B.

If voltage is OV. check: 1.

2.

3.

4.

Thermoprotector (check for voltage at gray lead. if above 3.4 volts the control is in thermal cutback, M~4 switch Accelerator pot adjustment RepIace card if items 1 through 4 are good

Table 7 Misoperation Of PMT Function.

Symptom 1.1A contactor closes when key switch is closed.

2.PMTD does not trip contactors when a fault occurs

Check Check for short between terminals 3 and 2 of 1 AD if shorted. b.

Replace 1 AD if shorted. a.

Replace PMTD if there are shorts between terminals 3 or 4 to 2 of the PMTD. b.

Replace card if PMTD is not shorted. a.

Table 8 Miscellaneous Symptoms.

Symptom 1.

Severe Plugging

2.

Soft reversal when plugging

3

Blown power fuse Burnt power wiring

Check a.

Plugging adjustment of card b.

4 Rec (open, c.

Replace control card d.

Green & yellow wire from snunt sensor a.

Plugging adjustment of card b.

Replace control card a.

3 Rec shoned (also possible damage to 1 Rec and transformer) b.

4 Rec (shorted) c.

Low battery voltage d.

Abnormal operating conditions— steep ramps. pushing loads. etc.

Typical EV-100 Wiring Diagram

Sheet 9: User Support Information