DOWNLOAD PDF BT Prime-Mover TMX Electric Tow Tractor Service Manual

SERVICE MANUAL Manual Part Number 303047-000 ELECTRIC TOW TRACTOR Effective Serial Number 255600

ISSUED APRIL 1995

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TMX

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TABLE OF CONTENTS

PAGE #

Section 0.0 Maintenance 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Tow Tractor Identification System Operation Specifications Maintenance and Adjustments Troubleshooting Component Removal and Installation Component Repair

0-1 0-2 0-3 0-14 0-20 0-20 0-20

Section 1.0 Transmission 1.1 1.2 1.3 1.4 1.5 1.6 1.7

Component Identification System Operation Specifications Maintenance and Adjustments Troubleshooting Component Removal and Installation Component Repair

1-2 1-6 1-6 1-6 1-7 1-7 1-13

Section 2.0 Electrical 2.1 2.2 2.3 2.4 2.5 2.6 2.7

Component Identification System Operation Specifications Maintenance and Adjustments Troubleshooting Component Removal and Installation Component Repair

2-3 2-10 2-13 2-13 2-19 2-32 2-36

Component Identification System Operation Specifications Maintenance and Adjustments Troubleshooting Component Removal and Installation Component Repair

4-2 4-6 4-6 4-6 4-6 4-6 4-6

Section 4.0 Frame 4.1 4.2 4.3 4.4 4.5 4.6 4.7

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0.0 MAINTENANCE

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0.1

Tow Tractor Identification This service manual covers the following BT Prime-Mover products: TMX ELECTRIC TOW TRACTOR from serial number 255600 and above.

These tow tractors are manufactured by The Prime-Mover Company in Muscatine, Iowa, USA. The Prime-Mover Company reserves the right to change the information and specifications contained within this manual at any time without incurring any obligation relating to such changes.

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0.2

System Operation Federal and State laws require that operators be completely trained in the safe operation of lift trucks.

An Operator's Manual is attached to every BT Prime-Mover electric tow tractor when it is manufactured. If the Operator's Manual is missing from the tow tractor a new manual may be obtained by contacting The Prime-Mover Company, 3000 North Highway 61, Muscatine, Iowa, 52761-5810, (319) 2627700.

This is a service manual is not a training manual. The information contained in this manual is intended as a guide to help the authorized technician safely service the truck.

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0.3

Specifications

0.3.1 Transmission Gear ratio

14.8:1

Oil type

GL5 85W90

Oil capacity

Approx. 1 liter

Drive tire size

10.5 X 5 X 6.5 "

0.3.2 Electrical Battery amp draw: At top speed empty

95 amps

Drive Motor: Min. brush length

.75"

New spring tension

56 oz.

Min. commutator diameter

2.625"

Towing capacity

6000 lbs

Top travel speed empty

7.5 mph

Top travel speed loaded

6.0 mph

Load wheel size

7" x 4"

Lubricating grease

Texas Refineries C & C #880

0.3.3 Frame

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INCH (SAE) AND METRIC FASTENERS

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Threaded fasteners like bolts, nuts, capscrews and studs are made to specifications that describe the mechanical strength and hardness of the fastener. A fastener used in a design application is selected according to its specifications. The Prime-Mover Company buys parts from many countries. There are several standards used by these countries in the manufacture of threaded fasteners. Many of these fasteners are similar, but cannot be used as direct replacement.

Service persons must use replacement fasteners that have the same specifications.

Fasteners made to each specification have identification marks for that specification.

This specification is commonly called "Grade" for SAE standards and "property" for metric standards. This section describes the identification of some common fasteners.

The metric system used by BT Prime-Mover is described as SI (International System of Units, also called SI in all languages). The SI system of measurement is described in ISO Standard 1000, 1973.

NOMENCLATURE, THREADS The thread design is specified by a series of numbers and letters for inch and metric fasteners. (See Figure 1). The diameter of the shank of the fastener is shown first in the series [M12=12mm, M20=20mm (1/2=1/2 inch, 3/4=3/4 inch)].

The number of threads per inch is normally not shown for inch nomenclature and only the UNC (Unified National Coarse) or UNF (Unified National Fine) is shown. This number of threads per inch is not shown because a UNC or UNF fastener has a standard number of threads per inch for a specific diameter.

The length of a shank is often indicated as part of the description of a fastener. This length is shown in inches for inch fasteners and in millimeters for metric fasteners.

A capscrew will have the following description:

A= B= C= D=

INCH

METRIC

1/2 x 13 UNC x 1-1/2 A B C D

M12 x 1.75 x 50 A B C

SHANK DIAMETER NUMBER OF THREADS PER UNIT OF LENGTH TYPE OF THREAD SHANK LENGTH

A= B= C=

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THREAD SIZE PITCH LENGTH

FIGURE 1 - THREAD DESIGN

STRENGTH IDENTIFICATION The most common property classes for metric fasteners are 8.8 and 10.9. The property class is marked with a number on the head of the capscrew or on a nut.

Property classes less then 8.8 are often not marked. Grades for inch bolts go from 2 to 8. Grade 2 fasteners normally do not have marks. The following tables show the marks that identify the grades and property classes for different fasteners.

When fasteners must be replaced, the new fasteners must be of the same strength or greater then the original fasteners. The new fasteners must also be the correct size.

NOTE: IDENTIFICATION MARKS ARE ACCORDING TO BOLT STRENGTH. THE HIGHER THE NUMBER OR THE INCREASE IN THE NUMBER OF MARKS INDICATES INCREASED BOLT STRENGTH.

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TABLE 1 - BOLTS AND SCREWS

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TABLE 2 - STUDS AND NUTS

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TABLE 3 - TORQUE NUTS

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TABLE 4 - TORQUE NUTS WITH NYLON INSERT

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TABLE 5 CONVERSION TABLE FOR METRIC AND ENGLISH UNITS AREA MULTIPLY BY

TO GET

MULTIPLY BY

TO GET

inches²

6.452

centimeters² (cm²)

centimeters²

0.155

inches² (in²)

feet²

0.093

meters² (m²)

meters²

10.764

feet² (ft²)

LINEAR MULTIPLY BY

TO GET

MULTIPLY BY

TO GET

inches

25.4

millimeters (mm)

millimeter

0.039

inches (in)

feet

0.305

meters (m)

meter

3.281

feet (ft)

yards

0.914

meters (m)

meter

1.094

yards (yd)

miles

1.609

kilometers (km)

kilometer

0.621

miles (mi)

MASS MULTIPLY BY

TO GET

MULTIPLY BY

TO GET

ounces (oz)

28.35

grams (g)

grams

0.035

ounces (oz)

pounds (lb)

0.454

kilograms (kg)

kilograms

2.205

pounds (lb)

tons (2000 lb)

907.18

kilograms (kg)

kilograms

0.001

tons (2000 lb)

tons (2000 lb)

0.907

metric ton (t)

metric ton

1.102

tons (2000 lb)

POWER MULTIPLY BY horsepower

0.746

TO GET

MULTIPLY BY

kilowatts (kW)

kilowatts

1.34

TO GET horsepower (hp)

PRESSURE MULTIPLY BY

TO GET

MULTIPLY BY

TO GET

pounds/in²

6.895

kilopascal (kPa)

kilopascals

0.145

pounds/in² (psi)

pounds/in²

0.007

megapascal (MPa)

megapascals

145.04

pounds/in² (psi)

TEMPERATURE

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MULTIPLY BY (°Fahrenheit-32)

0.56

TO GET

MULTIPLY BY

° Celsius (C)

(°Celsius x 1.8)

TO GET

+32

°Fahrenheit (F)

MULTIPLY BY

TO GET

TORQUE MULTIPLY BY

TO GET

pound inches

0.113

Newton meter (N.m)

Newton meter

8.851

pound inches (lbf in)

pound feet

1.356

Newton meter (N.m)

Newton meter

0.738

pound feet (lbf in)

VELOCITY MULTIPLY BY miles/hour

1.609

TO GET

MULTIPLY BY

kilometer/hour (km/h)

kilometer/hour

0.621

TO GET miles/hour (mph)

VOLUME MULTIPLY BY

TO GET

MULTIPLY BY

TO GET

inches³

16.387

centimeters³ (cm³)

centimeters³

0.061

inches³ (in³)

inches³

0.016

liters

liters

61.024

inches³ (in³)

quarts, U.S.

0.946

liters

liters

1.057

quarts, U.S (qt)

quarts, U.S.

0.83

quarts, Imp. (qt)

quarts, Imp.

1.205

quarts, U.S. (qt)

gallons, U.S.

3.785

liters

liters

0.264

gallons, U.S.

gallons, U.S.

0.83

gallons, Imp. (gal)

gallons, Imp.

1.205

gallons, U.S. (gal)

ounces

29.57

milliliters (ml)

milliliters

0.034

ounces (oz)

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TABLE 6 TORQUE VALUES FOR COARSE THREADED METRIC FASTENERS

Property, Class

Size and Pitch

8.8*

Property, Class

10.9**

Property, Class

12.9***

N.m

lbs ft

N.m

lbs ft

N.m

lbs ft

M5 x 0.8 M6 x 1

5-6 8-10

lbs in.

44-53 71-88

7-8 12-14

lbs in 62-71 106-124

8-10 14-16

lbs in 71-88 124-142

M8 x 1.25

20-25

30-35

lbs ft 22-26

34-40

lbs ft 26-30

M10 x 1.5

40-45

177-221 lbs ft 30-33

60-65

44-48

70-75

52-55

M12 x 1.75 M14 x 2

70-80 110-125

30-33 52-59

100-110 155-180

74-81 114-133

115-130 180-210

85-96 133-155

M16 x 2 M20 x 2.5

170-190 340-380

125-140 251-280

240-270 450-500

177-199 332-369

280-320 550-600

207-236 406-443

M24 x 3

580-650

428-479

800-900

590-664

900-1050

664-774

M30 x 3.5

11501300

848-959

16001800

1180-1328

1850-2100

13641549

M36 x 4

20002250

14791660

28003150

2065-2323

3250-3700

23972729

* Property class 8.8, Protective Treatment CMHC Specification "H" (zinc phosphate), apply also to internally threaded fasteners made of property class 8 material. **Property class 10.9, Protective Treatment CMHC Specification "H" (zinc phosphate), apply also to internally threaded fasteners made of property class 10 material. *** Property class 12.9, Protective Treatment CMHC Specification "H" (zinc phosphate), apply also to internally threaded fasteners of property class 12 material.

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0.4

Maintenance and Adjustments

0.4.1 Maintenance Planned Maintenance is a critical part of safe electric tow tractor operation. By following a regular schedule of planned maintenance procedures the correct and safe functioning of the electric tow tractor can be better assured. A good planned maintenance program will alert you to the need for adjustments and minor repairs and will greatly reduce the potential for unexpected failures.

An effective planned maintenance program will include a daily inspection to be made by the operator prior to each operating shift. This should include a visual inspection for damage, leaks, and fluid levels as well as testing for the correct operation of safety devices.

In addition to the operator's daily inspection a regular scheduled planned maintenance service should be performed by a qualified BT Prime-Mover technician. This service should include a thorough visual inspection, lubrication of service points, operational checks and minor adjustments.

The basic planned maintenance visit should be made every 200 operating hours or once every three months. Heavy truck usage is estimated at 200 hours per month, more detailed service should be performed once a year. A comprehensive schedule of planned maintenance operations and detailed planned maintenance procedures are in the sections that follow.

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PLANNED MAINTENANCE SCHEDULE SERVICES TO BE PERFORMED DAILY OR AT EACH 8 HOUR OPERATING SHIFT ITEM BATTERY FRAME/SHEET METAL WHEELS/TIRES FUNCTIONS/OPERATIONS

SERVICE TO BE PERFORMED CHARGE AND CHECK WATER INSPECT FOR LOOSE, DAMAGED, OR MISSING PARTS INSPECT FOR DAMAGE AND FOR TRASH IN BEARINGS TEST FOR PROPER OPERATION OF ALL FUNCTIONS

NOTES EQUALIZE CHARGE ONCE A WEEK ALL SHIELDS MUST BE IN PLACE SAFETY DEVICES MUST FUNCTION

SERVICES TO BE PERFORMED EVERY THREE MONTHS OR EVERY 200 OPERATING HOURS ITEM DAILY INSPECTION TRANSMISSION BRAKES BATTERY ELECTRICAL CONNECTIONS CONTACTOR TIPS FRAME LUBE PIVOT POINTS DRIVE MOTOR

SERVICES TO BE PERFORMED PERFORM DAILY INSPECTIONS CHECK FLUID LEVEL ADJUST AS NEEDED CHECK SPECIFIC GRAVITY CHECK FOR TIGHT AND CLEAN INSPECT FOR ARCING AND PITTING LUBRICATE ALL GREASE FITTINGS LUBRICATE ALL PIVOT POINTS BLOW OUT DRIVE MOTOR VENTS

NOTES

DO NOT FILE TIPS DRIP LUBE WITH 10 WT MACHINE OIL COMPRESSED AIR USED FOR CLEANING MUST BE REDUCED TO LESS THAN 30 PSI AND THEN ONLY WITH EFFECTIVE CHIP GUARDING AND PERSONAL PROTECTIVE EQUIPMENT

SERVICES TO BE PERFORMED EVERY 2000 OPERATING HOURS ITEM DAILY INSPECTION MONTHLY INSPECTION TRANSMISSION BATTERY BRAKES

SERVICE TO BE PERFORMED PERFORM DAILY INSPECTIONS PERFORM 200 HOUR INSPECTIONS DRAIN, FLUSH AND REFILL REMOVE FROM TRUCK AND CLEAN INSPECT BRAKE SHOE WEAR

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ALSO CLEAN BATTERY COMPARTMENT

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0.4.3 Planned Maintenance Procedures This section describes how to perform the services listed in the Schedule of Planned Maintenance Operations. As with the "Schedule" this section is subdivided into service intervals.

SERVICES TO BE PERFORMED DAILY OR AT EACH 8 HOUR OPERATING SHIFT:

The daily inspection is to be made by the operator prior to each operating shift.

It is the operator's responsibility to report any defects to the proper authorities and the truck should not be operated until it has been inspected and repaired by a qualified technician. The operator is ultimately responsible for the safe operation of this electric tow tractor.

Battery -

The battery should be charged when it reaches the 80% discharged level. This is indicated on the optional Battery Discharge Indicator when the single red LED bar on the far left is illuminated. A warning will be given at the 70% discharged level by means of the two red LED bars flashing alternately on and off. If the truck is equipped with the optional Speed Interrupt then speed reduction will occur at the 80% discharged level. If the optional Battery Discharge Indicator is not mounted then the battery should be charged after 6 to 8 operating hours.

Frame/Sheet Metal -

Inspect the electric tow tractor for loose, damaged or missing parts. All shields must be in place and functional. Report any problems to the proper authorities and do not operate the truck until it has been inspected and repaired by a qualified technician.

Wheels/Tires -

Inspect wheels and tires for wear and damage. Trash wrapped around wheels and axles will cause premature tire wear and bearing damage. Any trash should be removed before operating the electric tow tractor and the floors should be kept clear of trash to prevent damage to the wheels and tires.

Functions/Operations -

Test the electric tow tractor for the proper operation of all functions; including the travel controls and the brakes. Safety devices must be operational. Report any problems to the proper authorities and do not operate the electric tow tractor until it has been inspected and repaired by a qualified technician.

SERVICES TO BE PERFORMED MONTHLY OR EVERY 200 OPERATING HOURS:

The monthly planned maintenance service should be performed by a qualified technician.

Daily Inspection -

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All of the services and inspections listed above for the daily inspection should be performed at this time. The inspection procedure should be more thorough and minor deficiencies should be corrected.

Transmission -

Check the transmission fluid level. The level check point is a plug on the side cover of the transmission about 100 mm (4") above the bottom of the transmission case. Remove the plug and inspect the level of the fluid inside the transmission case. The fluid level should come to about 10 mm (3/8") below the plug and should never be above the level of the plug.

Brakes -

The brakes should hold fully loaded electric tow tractor from rolling on a 10% incline. The brakes should fully release when the brake control handle is in the release position. Adjust the brake linkage as required.

Battery -

At the 200 hour or monthly service interval, the specific gravity of the battery should be measured with a battery hydrometer. The difference in the highest cell and lowest cell readings should not be greater then 20 (.020) points.

An average battery will have a specific gravity of 1.170 at the 80% discharged level. However, there are many different batteries on the market and only the battery manufacturer can accurately determine the fully charged and 80% discharged levels. Contact the battery manufacturer for this information.

Electrical Connections -

All electrical connections should be checked that they are clean and tight.

Plug-in connectors should be unplugged and plugged back in to clean the terminals. If the truck is equipped with any of the cold-storage, freezer, or corrosive environment application packages then the di-electric compound in the plug-in connectors should be renewed. This compound is available through the parts department of your authorized dealer.

Contactor Tips -

Inspect contactor tips for arcing, pitting, or burning. Minor pitting of the tips is not a problem, however, if the tips are pitted through the tip to the copper bar the tips should be replaced. DO NOT file tips. Replace tips only in complete sets. Some contactors have concealed tips or are fully sealed so that tips cannot be replaced.

Drive Motor -

Blow out the drive motor fan and vents. Check for any signs of oil on the drive motor fan and air vents. Check for any damage to the fan or air vents.

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Compressed air used for cleaning MUST be reduced to less than 30 p.s.i., and then only with effective chip-guarding and personal protective equipment.

Frame Lube -

The pressure type grease fittings (zerk fittings) should be lubricated with Texas Refineries #880 Crown and Chassis lubricating grease. Look for grease fittings on the load wheels.

Pivot Points -

There are some pivot points and other items that need to be lubricated but do not have grease fittings. These include, but are not limited to, brake control linkage. Lubricate these non-greasable wear points with a drip oil can using 10 wt. machine oil.

SERVICES TO BE PERFORMED ANNUALLY OR EVERY 2000 OPERATING HOURS.

The annual planned maintenance service will take a longer period of time to complete then does the monthly service. This would be a good time to arrange other repairs that have been noted on the monthly service.

Daily Inspection and Monthly Inspection -

All of the services and inspections listed above for the daily and monthly inspection should be performed at this time. The inspection procedure should be more thorough and minor deficiencies should be corrected.

Transmission -

The transmission fluid should be drained. The drain port is the lower left hand bolt holding the side cover in place. Remove the bolt to drain the transmission fluid. Flush the transmission case with safety solvent by pouring clean solution into the level check plug in the side cover and allowing it to run out of the drain port while the transmission is running with the drive tire off the ground. Stop the flushing when the solution is running clean. Allow the solvent to drain well before replacing the drain plug bolt. Replace the drain plug bolt. Refill the transmission with the proper oil before operating truck.

Battery -

At the 2000 hour, or annual service interval it is recommended that the battery be removed from the truck for cleaning. Use fresh water to wash the battery and a soft, non-conductive brush to scrub the battery. Soda may be used to neutralize acid on the outside of the battery but care must be taken so that soda and water do not enter the battery cells. Also clean the battery compartment in the truck.

About every three years the battery should be inspected and serviced by the battery manufacturer's authorized service center.

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Brakes -

Remove brake drum and inspect brake shoe linings and brake drum for wear.

If the brake drum is damaged or worn a new drum should be fitted. The brake shoes should be replaced if the linings have worn down so much that the brakes will not meet stopping and holding specifications. See the procedures for adjusting brakes before replacing the brake shoes.

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Troubleshooting See individual sections on transmission, electrical, and frame for troubleshooting.

0.6

Component Removal and Installation See individual sections on transmission, electrical, and frame for component removal and installation.

0.7

Component Repair See individual sections on transmission, electrical, and frame for component repair.

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1.0 TRANSMISSION

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FIGURE # 1.1 TRANSMISSION ASSEMBLY

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1-2

FIG ITEM # # 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 19 19 19 19 19 20 21 21 21 21 21 21 22 23 24 25 26 27 28 29 30 31 32

# FOR ASSY.

NAME Seal, felt Bearing Seal, felt Bearing Case, gear Dowel Key Pinion, gear Nut (Torque 50 ft./lbs.)

Cover Screw, socket head (Torque 14 ft./lbs.)

Plug, drain/fill pipe Bearing Washer, sealing Set, gear Bearing Ring Seal Wheel, Flat rubber drive Wheel, Urethane drive Wheel, Non-marking XLC drive Wheel, Traction-lug drive Wheel, Grip rubber shell drive Wheel, Siped rubber Wheel, drive Tire, Flat rubber Tire, Urethane Tire, Non-marking XLC drive Tire, Traction-lug drive Tire, Grip rubber shell drive Tire, Siped rubber Nut, flanged (Torque 250 ft./lbs.)

Bracket, brake cable Motor, drive Drum, brake Brake assembly Cam Plate Lever Ring, retainer Spring Shoe

1-3

1 1 1 1 1 2 2 1 2 1 18 2 2 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2

Flat rubber Urethane Non-marking Traction-lug Grip rubber Siped rubber Flat rubber Urethane Non-marking Traction-lug Grip rubber Siped rubber

FIGURE # 1.2 STEERING STEM ASSEMBLY

CONNECT TO BRAKE

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1-4

FIG ITEM # # 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

# FOR ASSY.

NAME Stem, handle Screw, socket flat head Pin, yoke Cotter, internal Link, pivot Bushing, flanged Washer, shim (.030) Pin, groove Pin, spring Bracket, hand brake Control head assy. with Picking Knob Control head assy. without Picking Knob Cover Handle, brake Grip Bushing, sleeve Pivot Screw, socket head Spring Clevis Nut, jam Bar, brake link Screw, socket head Joint, ball Nut Handle, park brake Nut, clip Screw, socket flat head Knob Cover, brake Spring Nut, jam Anchor, spring Cable, brake Pin with cotter pin Screw, socket head

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1 6 1 1 1 2 4 2 2 1 1 1 1 1 2 2 2 2 2 1 1 1 1 1 1 1 2 2 1 1 1 1 1 1 1 6

1.2

SYSTEM OPERATION The transmission is of the double reduction type. The gears are a combination of helical and straight cut gears for strength and low noise. The final drive gear is mounted on opposing tapered roller bearings and the intermediate gear is mounted on ball bearings.

Gears and bearings are enclosed in an oil filled case. The drive motor is mounted externally with the drive motor pinion gear mounted on the armature shaft. The brakes are on the drive motor.

1.3

SPECIFICATIONS Gear Ratio Oil Type Oil Capacity Drive Tire Size

1.4

14.8:1 GL5 85W90 Approximately 1 liter 10.5" x 5" x 6.5"

MAINTENANCE AND ADJUSTMENTS Maintenance of the transmission is limited to the planned maintenance checks of the transmission fluid level and periodic changes of the transmission fluid. If the transmission fluid is discolored or has evidence of metal contamination then it is recommended that the transmission be inspected further to determine the cause.

The brake mechanism is connected directly to the drive motor and is covered in this section.

BRAKE THEORY OF OPERATION The brake in the TMX electric tow tractor is a cable operated design. The brake has a drum that is mounted on the drive motor armature shaft. The brake shoes are mounted on a backing plate that is bolted directly to the drive motor. This design gives excellent braking and long life since the drum and shoes are protected from dirt and other abrasive materials. Braking is accomplished by operating either one of two levers on the control handle. The levers are connected via a cable to the brake arm on the brake backing plate. The brake arm operates a cam that forces the brake shoes against brake drum.

This action clamps the brake shoes against drum and provides braking any time the handle lever is operated. When the lever is released a spring inside the brake drum returns the brake shoes and linkage to the "brake released" position.

The control handle stem has a parking brake lever mounted on the side towards the operator compartment. The parking brake is applied by lifting the lever and latching it in the slot provided. It is released by lifting the lever out of the latching slot and allowing it to go back down.

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BRAKE ADJUSTMENT

1.5

1.

Disconnect battery, block drive wheel off floor and open front access door.

2.

Place the parking brake linkage in the "brake released" position.

3.

Loosen the cable sheath mounting nuts at the bracket by the drive motor and adjust cable to increase or decrease braking action. To increase braking action move the cable sheath away from the bracket. (Move the mounting nuts toward the end of the cable.) To decrease the braking action move the cable sheath towards the bracket. (Move the mounting nuts to allow more of the threaded end of the cable to be exposed.)

4.

After the proper cable adjustment is made, tighten the mounting nuts to prevent the cable sheath from moving.

5.

Adjust brake interlock switch so that it operates as brakes are released and applied. The switch should close when the brakes are released.

6.

The brake drum may be removed and the operating lever moved one spline to compensate for brake shoe wear.

TROUBLESHOOTING Because of the uncomplicated nature of this transmission, troubleshooting is limited to identifying whether problems are mechanical or electrical in nature. Fluid leaks are obviously mechanical in nature and can be found by visual inspection. Unusual noise and/or slow running could be mechanical or electrical in nature. Generally speaking, if the problem is caused internally in the transmission then metal contamination will be evident in the oil. If there is a mechanical problem outside of the transmission then it will become evident by inspecting the drive motor and brakes.

1.6

COMPONENT REMOVAL AND INSTALLATION 1.6.1 TRANSMISSION REMOVAL AND INSTALLATION (ref. Figure #1.1 and #1.2).

OVERHEAD LIFTING DEVICE CAPABLE OF LIFTING 4000 LBS. IS REQUIRED. REMOVAL 1.

Disconnect the battery.

2.

Open access door on front of electric tow tractor and lift door off hinge.

3.

Remove cover on front of electric tow tractor.

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4.

Disconnect power cables from drive motor, label and remove from transmission case and housing. Cables may be left attached to control panel on electric tow tractor.

5.

Remove the cotter pin and the pin attaching the brake cable to the brake lever at the motor. Remove the wires to the brake interlock switch and detach the brake cable bracket.

6.

Remove the six (6) socket head screws (#36) that secure handle stem to transmission pivot tube. Lift handle stem from transmission.

Caution: Transmission assembly is secured to electric tow tractor frame with bolts that mount control handle tube.

7.

Use overhead lifting device to lift electric tow tractor off of transmission.

Bearing (Figure #1.1; item #2) may be tight on transmission tube.

Transmission must be supported to keep it from falling over when tube clears electric tow tractor frame.

8.

Remove transmission from under electric tow tractor.

INSTALLATION (Refer to Figure # 1.1) 1.

Place bearing cup (#4) into bore in bottom of electric tow tractor frame (shown in dashed lines). Bearing cup is a slip fit and may be retained using a dab of heavy grease between cup and frame.

2.

Place new felt seal material (#3) into groove formed by bearing cup and frame.

3.

Press bearing cone (#4) onto transmission case. Seat bearing tight on case. Using an inductive bearing heater will facilitate this operation.

Prelube bearing after installation.

4.

Raise electric tow tractor frame with overhead lifting device and position transmission under frame. Carefully lower frame onto transmission. Be careful to not dislodge bearing cup or felt seal.

5.

Install upper bearing cup and cone assembly (#2) and felt seal material (#1) on top of transmission tube. Prelube bearing cone.

6.

Route power cables and wires to the break interlock switch through transmission housing tube (#5). Connect cables to drive motor.

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7.

Install brake cable bracket, install brake interlock switch wires and attach cable to brake lever.

8.

Install handle stem, using six (6) socket head screws (#36).

9.

Install floor plate.

10.

Install door.

1.6.2 DRIVE WHEEL REMOVAL AND INSTALLATION REMOVAL The drive wheel can be removed without removing the transmission by following these steps: 1.

Disconnect the battery, block electric tow tractor with drive tire off floor (about 1 inch).

2.

Open front door and remove floor plate on front of electric tow tractor.

3.

Remove axle hub and wheel retaining nut. Pull tire and wheel from axle.

4.

Press drive tire from wheel hub. This is usually done in the same process as pressing on a new tire. See INSTALLATION.

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INSTALLATION 1.

Press drive tire in wheel hub. This is usually done while pressing off old tire. Press hub to center of tire.

2.

Install drive tire and hub on axle. The drive tire retaining nut should be torqued to 250 ft./lbs.

1.6.3 AXLE SEAL REMOVAL AND INSTALLATION REMOVAL The drive axle seal can be replaced without removing the gear case cover by following these steps: Before starting disassembly of any parts thoroughly clean outside of assembly with safety solvent or other non-corrosive cleaning fluid. Air dry all parts.

1.

Drain transmission oil.

2.

Disconnect the battery, block electric tow tractor with drive tire off floor (about 1 inch).

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3.

Open front door and remove floor plate from front of electric tow tractor for access.

4.

Remove drive wheel. See Section 1.6.2 above.

5.

Remove axle seal with seal puller or pry out with pry bar. Take care not to damage sealing surface or mounting bore.

INSTALLATION 1.

Check thread on hub and nut for damage.

2.

Install new oil seal.

3.

Install drive wheel and tire. The drive wheel retaining nut should be torqued to 250 ft./lbs.

4.

Lower electric tow tractor off blocks.

5.

Refill transmission case with new oil.

6.

Install floor plate and close front door.

1.6.4 BRAKE SHOE REMOVAL AND INSTALLATION REMOVAL 1.

Disconnect battery and block electric tow tractor with drive tire off floor (about 1 inch).

2.

Open front door for access to drive motor and brake drum.

3.

Loosen nut.

4.

Release parking brake.

5.

Remove brake drum.

6.

Lift brake shoes away from backing plate so that shoes come together in center and springs relax. Shoes can now be removed from backing plate together.

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7.

If the entire brake assembly with backing plate is to be replaced then disconnect brake cable and remove bolts holding backing plate to drive motor.

INSTALLATION 1.

If a new backing plate is to be fitted it comes with new brake shoes. Do not remove the brake shoes from the backing plate. Verify that the brake lever is mounted at the proper angle of 41° as shown below. A clip on the shaft retains the brake lever. Place backing plate with brake shoes attached into place on the drive motor. Raise each brake shoe individually and install mounting bolt into drive motor. Reconnect brake cable.

2.

If only new shoes are to be fitted install springs to brake shoes before installing shoes on backing plate. Place brake shoes and springs over backing plate and press into position. Use caution to prevent springs from flying out of place.

3.

Install brake drum and torque retaining nut to 25 ft. lbs.

4.

Adjust brake linkage and brake interlock switch (see Section 1.4.)

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1.7

COMPONENT REPAIR 1.7.1 TRANSMISSION DISASSEMBLY AND ASSEMBLY DISASSEMBLY After draining gear case lubricant, thoroughly clean outside with safety solvent or other non-corrosive cleaning fluid. Air dry all parts and proceed with disassembly of transmission as follows: 1.

Remove transmission from electric tow tractor. See Section 1.6

2.

Remove gear case cover.

3.

Block transmission with gear case side down. Allow room for gears to drop between blocks.

4.

Heat retaining collar with propane torch and press drive axle through collar and bearing. Drive axle and intermediate gear will come out together.

5.

Remove old bearings and races from gears and case. Clean transmission case.

ASSEMBLY Heat bearing cone on bearing heater to facilitate installation.

1.

Install new bearings on intermediate gear.

2.

Install new inner bearing cone on drive axle.

3.

Install new bearing cups in transmission case.

4.

Position transmission on work bench with gear case side up. Place drive axle and intermediate gear in case as a unit with gears meshed. Because of gear size and bearing interference these pieces cannot be installed separately.

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5.

Use Loctite #515 "gasket eliminator" on mating surface and install gear case side cover. Be sure that two dowel pins are in case to position cover.

Torque cover bolts to 14 ft./lbs.

6.

Reposition transmission case so that it rests on gear case cover.

7.

Install drive motor in transmission case.

8.

Install outer drive axle bearing cone and retaining collar:

9.

a.

Place bearing cone over shaft. Use a standard 1" x 14 nut, or reuse old nut, and bearing installation tool to push bearing on drive axle. At this time the bearing will not seat on shoulder of drive axle. Remove nut and pusher.

b.

Install drive axle seal in transmission case.

c.

Install collar on drive axle. Use bearing installation tool and nut to press collar on shaft. This should also press bearing down to seat on shoulder. Turn axle shaft while you torque nut to 250 ft./lbs. Control the drive axle turning by holding brake lever on drive motor.

Transmission assembly is now complete.

Install transmission in electric tow tractor and reinstall control handle. Route electric cables and control wiring through pivot tube. Liberally grease top and bottom bearing cones on pivot bearing. Bottom cup of pivot bearing is a slip fit in mounting frame, be certain that bearing cup has not fallen out of frame.

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2.0 ELECTRICAL

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THIS PAGE BLANK

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2.1

Component Identification The TMX electric tow electric tow tractors use the Curtis PMC transistor controller for travel speed control. This system allows the operator infinite variable speed control.

Electrical schematic and diagrams are shown on the following pages.

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FIGURE # 2.1 ELECTRICAL SCHEMATIC

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2-4

FIGURE # 2.2 ELECTRICAL SCHEMATIC SYMBOLS

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2-5

FIGURE # 2.3 ELECTRICAL ASSEMBLY

NOTE: USE HEAT CONDUCTING MATERIAL DOW #340 BETWEEN PANEL ASSEMBLY AND FRAME.

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2-6

FIG ITEM # # 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

# FOR NAME

ASSY.

Panel assembly Screw, socket flat head Harness, wiring Switch, emergency disconnect Switch, key Motor, drive Connector assembly Screw, Flat head Nut Screw, round head Nut, twin Sleeve ( 3 Feet) Clamp Plate, dash Cable Cable Screw, cap Plug, diode Plug, resistor 2.2K Plug, suppressor Filter, horn Nut Lockwasher Switch, overtravel Fitting, male disconnect tab Switch, sealed Clamp Alarm, travel Screw, thread form Gauge, HM/BDI/Speed Dropout Harness, speed dropout Fitting, wire splice Plug, resistor 1.5K Gauge, HM/BDI

2-7

1 4 1 1 1 1 1 2 2 4 2 As Req'd.

2 1 1 3 3 2 1 2 1 3 1 1 4 1 1 1 2 1 1 2 1 1

FIGURE # 2.4 ELECTRICAL PANEL ASSEMBLY

NOTE: USE HEAT CONDUCTING MATERIAL DOW #340 BETWEEN CONTROLLER AND PANEL PLATE.

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2-8

FIG ITEM # # 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

# FOR ASSY.

NAME Panel Controller Contactor Breaker, control Screw, socket head Suppressor, 15 OHM Screw, cap Horn Breaker, power (150 amp) Relay Contactor assembly, forward & rearward Nut Lockwasher Screw, cap Screw, thread form Screw, cap Lockwasher Fitting, male wire tab Resistor assembly Spacer, horn Screw, cap Screw, cap Bracket, switch Bar, buss Bar, buss Bar, buss Bar, buss Screw, cap Suppressor Bar, buss Bar, buss Resistor, field weakening Contactor assembly, field weakening Contactor assembly, 1A Delay, 1 second time Cable Cable Decal, DO NOT STEAM CLEAN

2-9

1 1 1 1 1 1 1 1 2 1 1 4 8 7 2 6 6 6 1 1 17 2 1 1 1 1 1 4 2 2 1 1 1 1 1 1 1 1

2.2

System Operation The BT Prime-Mover TMX electric tow electric tow tractors use a Curtis PMC transistor control to supply power to the series wound drive motor. This allows the operator infinite variable speed control.

These electric tow tractors are equipped with key switches for security, emergency disconnects for safety, and brake interlock switches to prevent drive operation if the brakes are applied.

During normal operation the following circuits are activated.

Battery connected and emergency disconnect push button switch pulled out to "run" position.

Battery positive voltage will be available via the battery positive cable, battery connector, and power cable to the positive side of the 150 amp drive motor circuit breaker. A buss bar connects the negative side of the drive motor circuit breaker to the positive side of the line contactor. Since the line contactor is not energized no current is flowing, but voltage can be read across the 250 ohm resistor.

Battery voltage is also available from the positive side of the 150 amp circuit breaker via wire #28, 12 amp circuit breaker, wire #26, emergency disconnect push button switch, and wire #27 to positive side of the key switch and battery discharge indicator input on optional BDI/HM. Because the BDI/HM display is connected directly to battery negative via wire #13 the battery discharge indicator will be illuminated to indicate the state of the battery charge.

Key switch turned "on"

With the key switch turned "on" positive battery voltage is available via the key switch and wire #6 to the brake interlock switch. Because the parking brake is not released the brake interlock switch will be open and no current will flow.

Positive battery voltage is also available via the key switch and wire #6 to the horn switches in the control handle.

Positive battery voltage is also available via the key switch and wire #6 to the hour meter display and to the optional cold storage heater circuit. The hour meter will display the hours used but will not begin accumulating hours until the electric tow tractor is operated.

Parking brake released and brake interlock switch closed.

With the brake interlock switch closed positive battery voltage will be available via wire #7 to the line contactor coil. Wire #13, battery negative, is connected to the other side of the line contactor coil therefore the line contactor coil is energized and the line contactor will close.

When the line contactor closes positive battery voltage is available through the line contactor to the B+ terminal on the Curtis PMC controller and to the A1 terminal on the drive motor.

Wire #7 also supplies voltage to the 1A bypass contactor coil, and to a terminal on 2-10

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the Curtis PMC controller to turn on the controller. Wire #7 is connected to the time delay for the field weakening contactor coil. Although the electric tow tractor is not moving the Curtis PMC controller has been turned on to recognize SRO signal inputs.

Reverse travel switch is closed.

When the reverse switch is closed to make the electric tow tractor travel in reverse direction positive battery voltage is made available via wire #3 to the reverse contactor coil. Wire #3 also supplies battery positive voltage to the PMC controller to signal it that a direction has been selected.

Wire #3 also supplies voltage through a diode to wire #37 and on to the hour meter run input on the hour meter/BDI. Battery negative for the reverse coil is supplied via wire #21 through the PMC controller. When the controller has satisfied its safety circuits the reverse contactor coil is energized and the reverse contactor will close. At this time the Curtis PMC controller will start "pulsing" power to the drive motor at a rate based on the accelerator potentiometer position. The PMC power circuit and the accelerator potentiometer circuit are described later.

Forward travel (control handle direction) switch is closed.

When the forward switch is closed to make the electric tow tractor travel in the control handle direction positive battery voltage is made available via wire #2 to the forward contactor coil. Wire #2 also supplies battery positive voltage to the PMC controller to signal it that a direction has been selected.

Wire #2 also supplies voltage through a diode to wire #37 and on to the hour meter run input on the hour meter/BDI. Battery negative for the forward coil is supplied via wire #21 through the PMC controller. When the controller has satisfied it safety circuits the forward contactor coil is energized and the forward contactor will close. At this time the Curtis PMC controller will start "pulsing" power to the drive motor at a rate based on the accelerator potentiometer position. The PMC power circuit and the accelerator potentiometer circuit are described later.

Curtis PMC controller power circuits.

When either the forward or reverse contactors are closed current will flow from the battery positive terminal through the battery cable, through the 150 amp circuit breaker, through the line contactor to the B+ terminal on the Curtis PMC controller.

From the B+ terminal through the drive motor armature, A1 to A2, through the normally open (now closed) contacts of the chosen direction contactor; through the drive motor field coils (S1 to S2 or S2 to S1 depending on direction), through the normally closed contacts of the opposite direction contactor, to the M- terminal of the Curtis PMC controller.

The current flowing into the M- terminal will be connected internally in the Curtis PMC controller to the B- terminal which is connected directly to the battery negative terminal.

Inside the Curtis PMC controller a high power semi-conductor switch, consisting of 2-11

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an array of paralleled power MOSFET transistors, controls the current through the drive motor. The transistors are turned on and off at the rate of 15,000 times per second by the control circuitry, while the ratio of the on and off times is regulated by the input of the accelerator potentiometer. This is called Pulse Width Modulation. When the transistors are on, current flows through the drive motor and builds up energy in the motor's magnetic field. When the transistors turn off, this stored energy continues to flow in the drive motor through the freewheel, or flyback diode. Thus, the average motor current is greater then the average battery current and smooth, stepless control of the power delivered to the drive motor is achieved with very little power loss in the control components.

Accelerator Potentiometer Circuits

The accelerator potentiometer is used to signal the Curtis PMC controller of the desired motor speed. By controlling the position of the accelerator potentiometer the operator can control the travel speed of the electric tow tractor.

The accelerator potentiometer is connected between terminals 2 and 3 on the Curtis PMC controller. When in neutral the resistance through the accelerator potentiometer is high, approximately 5200 ohms. As the electric tow tractor controls are operated to a higher travel speed the resistance through the accelerator potentiometer decreases. The resistance should decrease to below 50 ohms at full speed.

The resistance of the accelerator potentiometer is used to regulate the voltage potential on terminals 2 and 3 of the Curtis PMC controller. In neutral with a high resistance through the accelerator potentiometer the voltage potential, with respect to battery negative will be 1.85 volts +/- 10% on terminal 3 and 5.20 volts +/- 10% on terminal 2. When the controls are operated to high speed and the resistance through the accelerator potentiometer is at a minimum the voltage potential, with respect to battery negative, will equalize at 4.3 volts +/- 10% on both terminals 1 and 2.

Because the accelerator potentiometer is not polarity oriented it does not matter which lead of the potentiometer is connected to either terminal 2 or 3.

A platform switch is connected in the accelerator potentiometer circuit to limit travel speed in reverse. When the platform switch is not depressed the accelerator circuit is forced to go through an additional resistor. This causes the accelerator circuit to not go to high speed. When the operator is standing on the platform the switch is closed and travel speed is reduced in reverse (tow coupler leading).

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2.3

Specifications 2.3.1 Fuse and Circuit Breaker Ratings Control Circuit Breaker Power circuit breaker (auto reset)

12 amp 150 amp

2.3.2 Amp Draws (battery amps) Travel - full speed - empty

95A

2.3.3 Motor repair specifications Drive motor: Minimum brush length New brush spring tension 56oz Minimum commutator diameter 2.4

.75" 2.625"

Maintenance and Adjustments 2.4.1 Maintenance The electrical system requires little maintenance. Connections must be kept clean and tight and electrical components should be protected from moisture. Motor brushes should be inspected for minimum length at each month planned maintenance service and the motors should be cleaned using an approved compressed air blower. If the electric tow tractor is equipped with cold storage, freezer, or corrosive environment application package then the di-electric compound in the plug-in connectors should be renewed periodically. This compound is available through the parts department of your authorized dealer.

2.4.2 Adjustments Accelerator Potentiometer

The accelerator potentiometer is accessible inside the control handle head by removing the switch plate. The accelerator potentiometer operates off a gear toothed shaft (rack) that is moved when the travel controls are twisted.

To adjust the accelerator potentiometer: 1. Disconnect the battery.

2. Remove the six (6) outside screws securing the horn switch plate to the control handle head. Do not remove the center screw on the switch plate.

Remove the switch plate and lay it over to one side.

3. The accelerator potentiometer leads must be disconnected from the controller before connecting an ohmmeter for adjusting.

Remove the sheet metal console cover and disconnect wires #9 and #22 from the controller.

4. Connect ohmmeter leads to the accelerator potentiometer leads.

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5. In neutral the ohmmeter reading should be 5200 to 6000 ohms and will reduce to below 50 ohms as the travel controls are operated to high speed.

6. Loosen the mounting screws for the accelerator potentiometer mounting bracket and slide bracket up or down as necessary to make adjustments.

Hold the bracket snug against the handle housing while taking measurements.

If the slotted holes in the bracket do not allow enough adjustment then the bracket may be lifted slightly and the potentiometer drive gear can be rotated by one tooth.

7. Tighten bracket mounting screws and reassemble switch plate and covers.

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Brake Interlock Switch

The brake interlock switch is located on the brake cable bracket at the drive motor. It is activated by the brake lever. Its purpose is to shut off electrical power to the control of the drive motor when the brake is applied by opening the control circuit. To adjust the interlock switch: 1. Turn steering fully to left for access to brake interlock switch.

2. Disconnect battery.

3. Apply parking brake.

4. Loosen the two (2) bolts holding switch to bracket.

5. Adjust switch so that it is just opened.

6. Test switch operation. Switch should close when brakes are released.

Hourmeter with battery discharge indicator and speed reduction.

The speed reduction controller is built into the combination hour meter and BDI gauge. On the back of the gauge are two adjusting potentiometers labeled "discharge" and "reset". Adjustment is made by using a small screwdriver to rotate these potentiometer to the desired setting. The alphabetic settings and the linear markings are accurately calibrated and are precision repeatable from unit to unit.

The RESET potentiometer on all units leaves the factory set at RESET "B" which means the gauge will reset to "Full" if the voltage of a newly installed battery is above 2.09 VPC (volts per cell).

Turning the potentiometer clockwise from "B" to "E" increases the voltage per cell required to reset the gauge. Turning it counter-clockwise toward "A" decreases the voltage per cell required to reset the gauge.

Example: With the new generation batteries, particularly those of the high acid type, open circuit voltage can be a bit higher then in lower acid batteries. In such cases, to properly align the unit to the particular battery characteristics, simply adjust the RESET potentiometer to a level above the "C" marking for reset to occur when the battery's voltage is above 2.12 VPC, the higher open circuit voltage.

Example: In those circumstances when shutdowns cannot be tolerated because of the negative effect on productivity and it is necessary to use a partially charged battery, the gauge reset level can be decreased from 2.09 VPC to as low as 2.00 VPC. Though the gauge initially reads "Full" once it resets, as the equipment is used it will quickly catch up with the battery and provide a correct reading of the actual state-of-charge of the partially charged battery.

Keep in mind that RESET adjustments must be made prior to connecting the battery to the equipment. RESET adjustments made after battery/equipment 2-15

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connection have no effect. The RESET action is instantaneous. The gauge will reset or not within seconds. If reset does not occur and it is necessary to readjust the potentiometer setting, first unplug the battery and equipment, wait at least 10 seconds, adjust potentiometer to new setting and reconnect the battery.

The DISCHARGE potentiometer on all units leaves the factory set at DISCHARGE "N", which means the discharge profile is set for a final end point of 1.73 VPC, where speed reduction will occur. This profile has proven to be average.

Turning the potentiometer clockwise from "N" to "P" decreases the depth of discharge and, in turn, the operating time of the equipment. Turning it counterclockwise from "N" to "K" increases the depth of the discharge and, in turn, the operating time of the equipment.

Example: On occasion, equipment is required for work beyond its normally assigned work cycle and time does not permit changing of battery. In these cases, speed reduction can be delayed by increasing the depth of discharge from the standard 1.73 VPC ("N" setting) to as low as 1.56 VPC (beyond "K" setting).

Example: Equipment and battery are sized for the type of work they are used for. On occasion, equipment designated for heavy work might be used for light tasks. Lighter work means low-current drain which, in turn, means the recommended 80% depth of discharge lockout point will be at a higher voltage level. In these cases, to properly align the low-current work profile and the required higher speed reduction point, the DISCHARGE potentiometer can be adjusted to the "O" (1.78 VPC) or the "P" (1.82 VPC) settings.

It is important to note that adjustments of the DISCHARGE potentiometer can be made at any time during a work cycle prior to speed reduction. However, DISCHARGE potentiometer adjustments made late in a work cycle have little or no effect in delaying speed reduction in that particular work cycle. Once speed reduction does occur, the gauge must be reset before DISCHARGE potentiometer adjustments can have an effect.

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TABLE OF POTENTIOMETER SETTINGS AND ASSOCIATED VOLTAGES PER CELL

DISCHARGE

RESET

P

1.82 VPC*

E

2.18 VPC

O

1.78

D

2.15

N factory set

1.73

C

2.12

M

1.68

B factory set

2.09

L

1.63

A

2.06

K

1.57

Beyond A

2.00

Beyond K

1.56

*The DISCHARGE voltage of the unit is not an instantaneous voltage, nor a measure of the open circuit voltage at the time of speed reduction.

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Controller adjustments

This figure shows the locations of the adjustment potentiometer on the PMC controller.

To make the adjustments: 1. Remove the socket head screw (1/8" Allen) for the adjustment you want to make.

2. Adjust the small internal potentiometer with a small trim potentiometer adjustment tool. These are 270 degree turn potentiometers.

NOTE: If the proper tool is NOT used to adjust these potentiometers, it is possible to damage the printed circuit board causing the controller to fail.

3. Replace the socket head screw and nylon seal washer. Tighten to 8 inch/pounds.

4. These adjustments can be made to suit the operator.

Higher plugging current will mean a shorter stopping distance when plugging.

This distance should not be less than 10 feet.

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2.5

Troubleshooting Troubleshooting can be broken down into individual circuits. By knowing the exact symptoms of the electric tow tractor operation many hours of troubleshooting time can be saved. If the proper contactor operates for the chosen direction and speed then the problem can be found in the power circuit of that function. If a particular contactor does not operate when a function is chosen then the problem can generally be found in the control circuit of that function.

Only the travel functions are controlled by the transistor controllers. Horn function operates separately.

To use this troubleshooting guide locate the failure symptom in the index on the following pages then go to the expanded outline and follow the testing procedures described.

Voltage tests are made with the negative lead of the volt meter connected to battery negative. If the negative lead is connected to a negative terminal on the electrical panel you must first verify the negative connection to the battery by touching the positive meter lead to the positive battery post. The battery voltage must be at least 25.2 volts for a 24 volt system. If the battery voltage is below 22 volts (no load) then the controller may not operate properly. You will then have to charge the battery before starting the troubleshooting procedures.

When testing voltage, the "POSITIVE SIDE" of any component refers to the terminal on that component that is closest electrically to the battery positive terminal. The "NEGATIVE SIDE" of any component refers to the terminal on that component that is farthest electrically from the battery positive terminal. It is possible, and in many cases desirable, to measure battery voltage on the negative side of a component.

"Forward" direction refers to travel in the direction of the control handle with the tow coupler trailing. "Reverse" direction refers to travel with the tow coupler leading.

After the final test is completed the electric tow tractor should be repaired and operating properly. If it is not, then you must verify your test results and possibly re-evaluate the failure symptoms. If you still have not repaired the electric tow tractor then you should call your local BT Prime-Mover dealer for assistance. When you call, the following information is required: Electric tow tractor model and serial number, service meter hours, actual battery voltage at open circuit, the precise operating symptoms, and the exact results of the testing you have done. Authorized BT Prime Mover dealers may call the factory directly if necessary.

The first steps of any troubleshooting procedure are to: 1. Inspect the electric tow tractor for physical damage or mechanical malfunction.

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Contactors must be free to move and the tips must not be welded or burnt.

2. Check for ground faults from the electrical system to the frame with an ohmmeter. A minimum of 20,000 ohms resistance from the frame to any and all wiring is acceptable.

3. Check that the battery is fully charged and connected.

4. Operate the electric tow tractor in all modes to determine the exact symptoms. Do not forget that these systems are equipped with safety circuits that prevent operation in the event of improper operating procedures.

The following troubleshooting charts describe a course of testing and repair for each problem listed. If the given test is NOT successful perform the repair listed with the test.

If the given test IS successful, move on directly to the next test or follow the special instructions given.

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TROUBLESHOOTING CHART INDEX 2.5.1 Dead electric tow tractor, nothing operates. No travel, no horn.

2.5.2 No travel, line contactor does not close. The horn function works.

2.5.3 No reverse travel; reverse contactor will not close when travel controls are operated. The horn function works.

2.5.4 No forward travel ; forward contactor will not close when travel controls are operated.

The horn function works.

2.5.5 No reverse travel; reverse contactor does close when travel controls are operated. The horn function works.

2.5.6 No forward travel; forward contactor does close when travel controls are operated. The horn functions work okay.

2.5.7 Electric tow tractor travel speed does not respond to controls properly. Contactors close for chosen direction but electric tow tractor does not have full speed control.

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TROUBLESHOOTING CHARTS 2.5.1 Dead electric tow tractor, nothing operates. No travel, no horn.

Conditions for testing: Electric tow tractor raised and blocked with drive tire off ground.

Battery fully charged and connected to electric tow tractor.

Emergency disconnect pushbutton switch pulled out to the "run" position.

Key switch turned "on".

Test for voltage at: A. Positive side of 150 amp power circuit breaker.

Repair open power cable between battery positive terminal and 150 amp power circuit breaker.

B. Positive side of 12 amp control circuit breaker, wire #28.

Repair open wire #28 between 150 amp power circuit breaker and 12 amp control circuit breaker.

C. Negative side of 12 amp control circuit breaker, wire #26.

Replace 12 amp control circuit breaker.

D. Positive side of emergency disconnect pushbutton switch, wire #26.

Repair open wire #26 between 12 amp control circuit breaker and emergency disconnect pushbutton switch.

E. Negative side of emergency disconnect pushbutton switch, wire #27.

Replace emergency disconnect pushbutton switch.

F. Positive side of key switch, wire #27.

Repair broken wire #27 between emergency disconnect pushbutton switch and key switch.

G. Negative side of key switch, wire #6.

Replace key switch.

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H. If electric tow tractor is not functioning re-evaluate symptoms and troubleshoot individual functions.

2.5.2 No travel, line contactor does not close.

Horn functions okay.

Conditions for testing: Electric tow tractor raised and blocked with drive tire off ground.

Battery fully charged and connected to electric tow tractor.

Emergency disconnect pushbutton switch pulled out to the "run" position.

Key switch turned "on".

Test for battery voltage at: A. Positive side of brake interlock switch, wire #6.

Repair wire #6 between key switch and brake interlock switch.

B. Negative side of brake interlock switch, wire #7.

Adjust or replace brake interlock switch.

C. Positive side of line contactor coil, wire #7.

Repair open wire #7 between brake interlock switch and line contactor coil.

E. Negative side of line contactor coil, wire #13.

Special instructions: If battery voltage is found here then repair open wire #13 to battery negative.

If no battery voltage is found here then replace line contactor coil.

2.5.3 No reverse travel; reverse contactor will not close when travel controls are operated. The horn function works.

Conditions for testing: Electric tow tractor raised and blocked with drive tire off ground.

Battery fully charged and connected to electric tow tractor.

Emergency disconnect pushbutton switch pulled out to the "run" position.

Key switch turned "on".

Travel controls operated to travel in the reverse direction (tow coupler leading).

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Brake released.

Test for battery voltage at: A. Wire #7 terminal on transistor controller.

Repair open wire #7 between brake interlock switch and transistor controller.

B. Positive side of reverse direction control switch, wire #7.

Repair open wire #7 between brake interlock switch and reverse direction control switch.

C. Negative side of reverse direction control switch, wire #3.

Replace reverse direction control switch.

D. Positive side of reverse contactor coil, wire #3.

Repair open wire #3 between reverse direction control switch and reverse contactor coil.

E. Negative side of reverse contactor coil, wire #21.

Repair or replace contactor.

F. Pin #3, wire #21, at seven-pin, plug-in connector on PMC controller.

0 volts - unplug seven-pin connector and retest pin #3, wire #21. If still 0 volts, repair open wire #21 between negative side of rearward contactor coil and pin #3 on sevenpin connector.

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2.5.4 No forward travel; forward contactor will not close when travel controls are operated. The horn function works.

Conditions for testing: Electric tow tractor raised and blocked with drive tire off ground.

Battery fully charged and connected to electric tow tractor.

Emergency disconnect pushbutton switch pulled out to the "run" position.

Key switch turned "on".

Travel controls operated to travel in the forward direction (tow coupler trailing).

Brake released Test for battery voltage at: A. Wire #7 terminal on transistor controller.

Repair open wire #7 between brake interlock switch and transistor controller.

B. Positive side of forward direction control switch, wire #7.

Repair open wire #7 between brake interlock switch and forward direction control switch.

C. Negative side of forward direction control switch, wire #2.

Replace forward direction control switch.

D. Positive side of forward contactor coil, wire #2.

Repair open wire #2 between forward direction control switch and forward contactor coil.

E. Negative side of forward contactor coil, wire #21.

Repair or replace contactor.

F. Pin #3, wire #21, at seven-pin, plug-in connector on PMC controller.

0 volts - unplug seven-pin connector and retest pin #3, wire #21. If still 0 volts, repair open wire #21 between negative side of rearward contactor coil and pin #3 on sevenpin connector.

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2.5.5

No reverse travel; reverse contactor does close when travel controls are operated.

The horn function works.

Conditions for testing: Electric tow tractor raised and blocked with drive tire off ground.

Battery fully charged and connected to electric tow tractor.

Emergency disconnect pushbutton switch pulled out to the "run" position.

Key switch turned "on".

Travel controls operated to travel in the reverse (tow coupler leading) direction with reverse contactor closed.

Test for battery voltage at: A. Positive side of 150 amp circuit breaker.

Repair open power cable between battery positive terminal and 150 amp circuit breaker.

B. Negative side of 150 amp circuit breaker.

Replace 150 amp circuit breaker.

C. Positive side of line contactor tips.

Repair open power cable between 150 amp circuit breaker and line contactor.

D. Negative side of line contactor tips.

Repair or replace line contactor.

E. B+ terminal on transistor controller.

Repair open power cable between line contactor and transistor controller.

F. A1 terminal on drive motor.

Repair open power cable between transistor controller B+ terminal and drive motor A1 terminal.

G. A2 terminal on drive motor.

Repair drive motor.

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H. S1 terminal on drive motor.

Repair open power circuit between drive motor A2 terminal and drive motor S1 terminal. NOTE: This includes the normally open (N.O.) reverse contactor tips.

I. S2 terminal on drive motor.

Repair drive motor.

J. M- terminal on transistor controller.

Repair open power circuit between drive motor S2 terminal and M- terminal on transistor controller. NOTE: This includes the normally closed (N.C.) forward contactor tips.

K. B- terminal on transistor controller.

Special Instructions: If battery voltage is found here then repair open power cable to battery negative.

If no battery voltage is found here then it is possible that the transistor controller has failed. Before replacing the transistor controller perform the tests for the accelerator potentiometer listed in Chart 2.5.7.

2.5.6

No forward travel; forward contactor does close when travel controls are operated.

The horn function works.

Conditions for testing: Electric tow tractor raised and blocked with drive tire off ground.

Battery fully charged and connected to electric tow tractor.

Emergency disconnect pushbutton switch pulled out to the "run" position.

Key switch turned "on".

Travel controls operated to travel in the forward (tow coupler trailing) direction with forward contactor closed.

Test for battery voltage at: A. Positive side of 150 amp circuit breaker.

Repair open power cable between battery positive terminal and 150 amp circuit breaker.

B. Negative side of 150 amp circuit breaker.

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Replace 150 amp circuit breaker.

C. Positive side of line contactor tips.

Repair open power cable between 150 amp circuit breaker and line contactor.

D. Negative side of line contactor tips.

Repair or replace line contactor.

E. B+ terminal on transistor controller.

Repair open power cable between line contactor and transistor controller.

F. A1 terminal on drive motor.

Repair open power cable between transistor controller B+ terminal and drive motor A1 terminal.

G. A2 terminal on drive motor.

Repair drive motor.

H. S2 terminal on drive motor.

Repair open power circuit between drive motor A2 terminal and drive motor S2 terminal. NOTE: This includes the normally open (N.O.) forward contactor tips.

I. S1 terminal on drive motor.

Repair drive motor.

J. M- terminal on transistor controller.

Repair open power circuit between drive motor S2 terminal and M- terminal on transistor controller. NOTE: This includes the normally closed (N.C.) reverse contactor tips.

K. B- terminal on transistor controller.

Special Instructions: If battery voltage is found here then repair open power cable to battery negative.

If no battery voltage is found here then it is possible that the transistor controller has failed. Before replacing the transistor controller perform the tests for the 2-28

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accelerator potentiometer listed in Chart 2.5.7.

2.5.7

Electric tow tractor travel speed does not respond to controls properly. Contactors close for chosen direction but electric tow tractor does not have full speed control.

NOTE: There are two series of tests for the accelerator potentiometer circuits. The first series will test the resistance through the potentiometer circuit and the second series will test the control voltages on the transistor controller.

Resistance testing

Conditions for testing: Battery disconnected from electric tow tractor.

Electric tow tractor blocked to prevent it from rolling.

Wires #9 and #22 removed from transistor controller.

Access cover removed from control handle to allow access to accelerator potentiometer.

Test Procedure A: Connect an ohmmeter with at least a 10K ohm scale to wires #9 and #10 that are connected to accelerator potentiometer. The purpose is to test the resistance through the accelerator potentiometer as the travel controls are operated through their full range in both directions. Operate travel controls slowly and smoothly to full speed in both directions; read ohmmeter.

Test Results: In neutral the resistance should be approximately 5000 ohms through the accelerator potentiometer. As the controls are operated to high speed the resistance through the accelerator potentiometer should drop smoothly to below fifty (50) ohms.

Recommended Action: If the test indicates an open circuit between wires #9 and #10 then replace the accelerator potentiometer.

If the test indicates zero (0) ohms resistance between wires #9 and #10 then replace the accelerator potentiometer.

Test Procedure B:

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Connect one lead of the ohmmeter to wire #9 at the accelerator potentiometer and the other lead of the ohmmeter to wire #9 that was removed from the transistor controller.

Test Results: The ohmmeter should indicate zero (0) ohms resistance in wire #9.

Recommended Action: If the ohmmeter indicates significant resistance in this wire than repair or replace wire #9. Be sure to check wiring harness connectors for corrosion when repairing wire.

Test Procedure C: Conditions for testing: Same as for test A and B, except with battery plugged-in so high speed relay can be energized when the platform switch is closed.

Connect one lead of the ohmmeter to wire #10 at the accelerator potentiometer and the other lead of the ohmmeter to wire #22 that was removed form the transistor controller. Read resistance indicated on meter and then press the high speed "platform" switch, read resistance measured on meter again.

Test Results: The first resistance reading should be in the neighborhood of 1800 ohms and when the "platform" switch is pushed the resistance should drop to zero (0) ohms.

Recommended Action: If the resistance readings are not correct than repair or replace wire #10 or #22, or repair or replace the High speed "rabbit" switch or 1800 ohm resistor in parallel with the switch.

Voltage Testing

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Conditions for testing: Wires #9 and #22 reconnected to transistor controller.

Electric tow tractor raised and blocked with drive tire off ground.

Battery fully charged and connected to electric tow electric tow tractor.

Emergency disconnect pushbutton switch pulled out to the "run" position.

Key switch turned "on".

Test Procedure: Connect a volt meter with at least a 20 volt DC scale to the terminals on the transistor controller with wires #9 and #22 connected. The purpose is to test the voltage differential between wires #9 and #22 as the travel controls are operated through their full range. Operate travel controls slowly and smoothly to full speed: read volt meter.

Test Results: In neutral the voltage difference should be 6 to 7 volts DC. As the controls are operated to high speed the voltage should drop to close to zero (0) volts difference.

Recommended Action: If the test indicates proper accelerator voltage then replace the transistor controller.

NOTE: Some mechanical problems, such as brake adjustment, could cause the same symptoms. Be sure that this is not the case before replacing the transistor controller.

If the test indicates improper accelerator voltage then verify correct resistance tests before replacing transistor controller.

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2.6

COMPONENT REMOVAL AND INSTALLATION 2.6.1 DRIVE MOTOR REMOVAL AND INSTALLATION REMOVAL 1. Disconnect the battery, block unit from moving and remove cover door.

2. Disconnect brake linkage at clevis and remove brake cable bracket from case.

3. Disconnect power cables and note their proper position.

4. Remove four (4) motor mounting bolts (motor will be loose when bolts are removed).

5. Place drive motor assembly on a bench to continue disassembly.

6. Remove locknut and pinion gear from motor armature shaft.

7. Remove locknut and brake drum from motor armature shaft.

By lifting one brake shoe of the brake assembly at a time the mounting bolts can be removed without disassembling the brake assembly.

8. Clean gasket eliminator from face of motor and transmission housing.

Surfaces must be thoroughly cleaned.

9. To disassemble motor see the section in this manual covering the motor assembly.

INSTALLATION The drive motor can be reinstalled without removing the gear case cover by following these steps: 1. Thoroughly clean all parts with safety solvent or other non-corrosive cleaning fluid. Air dry all parts.

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2. Install brake assembly by lifting one brake shoe at a time and installing mounting bolts.

NOTE: LOCATION OF ACTIVATING LEVER SHOULD BE AS SHOWN. 3.

Install brake drum on the armature shaft over the key.

4.

Install pinion gear on drive motor over the key and tighten locknut.

Placing a wrench on both locknuts tighten nut to 30 ft./lbs.

5.

Apply gasket eliminator (Loctite 515) on mating faces of motor and transmission.

6.

Slide drive motor in gear case and work it around until the pinion gear lines up with intermediate gear.

7.

Install the four (4) motor mounting bolts and torque to 35 ft./lbs.

8.

Connect the power cables to their proper terminal.

9.

Install brake cable bracket and linkage.

10.

Reinstall cover door.

11.

Remove blocks, connect battery and test operation of unit.

2.6.2 DRIVE MOTOR BRUSH REMOVAL AND INSTALLATION REMOVAL 1.

Disconnect battery before beginning work.

2.

Remove the shields around motor end cover to expose brushes.

4.

Remove screw holding brush lead.

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5.

Lift spring off brush, remove brush from holder.

INSTALLATION 1.

Place new brushes in holder in same orientation that old brushes were removed and tighten screws on brush leads.

2.6.6 CONTACTOR TIPS CONTACTOR TIP REMOVAL AND INSTALLATION SHOCK HAZARD!!! Disconnect battery before doing any work on/or around contactor panel assembly.

CONTACTOR TIP/BAR REPLACEMENT 1.

Contactor tips are the only serviceable part of contactors. The bars should be replaced when tips have worn through the silver contact in any area.

2.

Disconnect buss bars from contactors.

3.

Remove screws holding contactor cover in place.

4.

Remove cover, being careful not to drop springs.

5.

Install new bars and tips.

6.

Install cover with springs in correct place.

2.6.7 DIRECTION CONTROL SWITCHES The direction control switches are mounted in the control handle head. It is not necessary to remove the head to change the switches.

1.

Remove the screws around the outer edge of the switch cover plate on the control handle head. Do not remove the center screw. Lay cover to side.

2.

Remove two screws holding forward/reverse switch bracket to housing and remove bracket.

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3.

Remove switch wires from wire harness plug and remove switches and bracket.

4.

The switches may now be replaced by unbolting them from the bracket.

5.

Reconnect switch wires and reinstall bracket in housing.

6.

Test switch operation and adjust bracket before installing switch cover plate.

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2.7

COMPONENT REPAIR 2.7.1 DRIVE MOTOR DISASSEMBLY 1.

Remove motor brushes.

2.

Remove four screws holding brush end bell to field housing.

3.

Separate end bell from field housing. The armature will come out with end bell.

Troubleshooting When a motor has trouble in operation, a reasonable decision has to be made as to the proper corrective course of action. We have reviewed many troubleshooting guides, and have reduced them to a few which seem to be the most effective Symptom\Cause relationships.

Table 1 - Indications, Causes and Correction of Unsatisfactory Brush Performance.

Table 2 - Primary Sources of Unsatisfactory Brush Performance.

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TABLE 1 INDICATIONS, CAUSES AND CORRECTION OF UNSATISFACTORY BRUSH PERFORMANCE INDICATIONS IMMEDIATE CAUSES PRIMARY FAULTS

Sparking

Commutator surface condition Over-commutation Under-commutation Too rapid reversal of current Faulty machine adjustment Mechanical fault in machine Electrical fault in machine Bad load condition Poor equalized parallel operation Vibration Chattering of brushes Wrong brush grade Fluctuating contact drop

Etched or Burned Bands on Brush Face

Pitting of Brush Face

20-21-28-29 25-27-28-29 38-39-40-41-42 7-13-23-34 51-52 See "Chattering or Noisy Brushes" 55-57-59 50

Glowing

See "Glowing at Brush Face" See "Copper in Brush Face"

Commutator surface condition

7-12-30-32

See specific surface fault in evidence.

Also 50.

See "Sparking" 11-14-15-16-51-52 54-58

Embedded copper

See "Copper in Brush Face"

Faulty machine adjustment Severe load condition Bad service condition Wrong brush grade

7-12 38-39-41-42 46-47 57-61-62

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6-14-15-16-17-18-19-

7-12-31-33 7-12-30-32

Severe sparking Imperfect contact with commutator Wrong brush grade Glowing at Brush Face

7-12-30-32 8-9-11

Over-commutation Under-commutation Too rapid reversal of current

Embedded copper Rapid Brush Wear

1-2-3-43-44-45-46-4959-60 7-12-31-33 7-12-30-32

Copper in Brush Face

Commutator surface condition Bad service condition Wrong brush grade

2-3 43-46-47-48-49 59-61

Flashover at Brushes

Machine condition Bad load condition Lack of attention

14-35 38-39-41-53 5-11

Chattering or Noisy

Commutator surface condition Looseness in machine Faulty machine adjust High friction Wrong brush grade

See specific surface fault in evidence 15-16-17 10-11 6-43-45-49-52-58-59 55-58-59

INDICATIONS APPEARING AT COMMUTATOR SURFACE

INDICATIONS Brush Chipping or Breakage

IMMEDIATE CAUSES Commutator surface condition Looseness in machine Vibration Chattering

See specific surface fault in evidence 15-16-17 52 See "Chattering or Noisy Brushes"

Sluggish brush movement

14

Rough or Uneven Surface

1-2-3-4-17

Dull or Dirty Surface

5-44-60

Eccentric Surface

1-19-22-52

High Commutator Bar

Sparking

17

Low Commutator Bar Streaking or Threading of Surface

Sparking Copper or foreign material in brush face Glowing

2-25 43-44-45-46-49-59

Bar Etching or Burning

Sparking Flashover

2-3-7-12-30-31-32-33 5-11-14-35-38-39-41-53

Bar Marking at Pole Pitch Spacing

Sparking

25-37

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PRIMARY FAULTS

2-3-46-47-48-61 See "Glowing at Brush Face"

Bar Marking at Slot Pitch Spacing

Sparking

7-12-30-57-60

Flat Spot

Sparking Flashover Lack of attention

19-23-25-41-53 5-11-14-35-38-39-41-53 1-5-11

Discoloration of Surface

High temperature

See "Heating at Commutator" 44-46 60

Atmospheric condition Wrong brush grade Raw Copper Surface

Embedded copper Bad service condition Wrong brush grade

See "Copper in Brush Face" 43-45-47-49 59-61

Rapid Commutator Wear with Blackened Surface

Burning Severe Sparking

2-3-11-14 See "Sparking"

Rapid Commutator Wear with Bright Surface Copper Dragging

Foreign material in brush face Wrong brush grade Brush vibration

43-45-47-49 61 39-52-58-59

INDICATIONS APPEARING AS HEATING

INDICATIONS Heating in Windings

Heating at Commutator

IMMEDIATE CAUSES Severe load condition Unbalanced magnetic field Unbalanced armature currents Poorly equalized parallel operation Lack of ventilation

38-41-42-53

Severe load condition Severe sparking High friction

38-41-42 7-8-9-12-20-33-45-57 10-11-36-43-45-49-5859 See specific surface fault in evidence 6-24

Poor commutator surface Depreciation High contact resistance

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PRIMARY FAULTS

18-19-20-21-27-28-29 8-19-22-25-27-28-29-37 7-13-23-34

56

Heating at Brushes

Severe load condition Faulty machine adjustment Severe sparking Raw streaks on commutator surface Embedded copper Wrong brush grade

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38-41-42 7-10-11-12-26 See "Sparking" See "Streaking or Threading of Surface" See "Copper in Brush Face" 57-58-59-61-62

TABLE 2 PRIMARY SOURCES OF UNSATISFACTORY BRUSH PERFORMANCE PREPARATION AND CARE OF MACHINE 1.

2.

3.

4.

5.

6.

Poor preparation of commutator surface High mica Feather-edge mica Bar edges not chamfered after undercutting Need for periodic cleaning Clogged ventilating ducts

MACHINE ADJUSTMENT 7.

8.

9.

10.

11.

12.

13.

Brushes in wrong position Unequal brush spacing Poor alignment of brushholders Incorrect brush angle Incorrect spring tension Interpoles improperly adjusted Series field improperly adjusted

MECHANICAL FAULT IN MACHINE 14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

Brushes tight in holders Brushes too loose in holders Brushholders loose at mounting Commutator loose Loose pole pieces or pole-face shoes Loose or worn bearings Unequal air gaps Unequal pole spacing Dynamic unbalance Variable angular velocity Commutator too small

ELECTRICAL FAULT IN MACHINE 25.

26.

27.

28.

29.

Open or high resistance connection at commutator Poor connection at shunt terminal Short circuit in field or armature winding Ground in field or armature winding Reversed polarity on main pole or interpole

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MACHINE DESIGN 30.

31.

32.

33.

34.

35.

36.

37.

Commutating zone too narrow Commutating zone too wide Brushes too thin Brushes too thick Magnetic saturation of interpoles High bar-to-bar voltage High ratio of brush contact to commutator surface area Insufficient cross connection of armature coils

LOAD OR SERVICE CONDITION 38.

39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

Overload Rapid change of load Reversing operation of non-interpole machine Plugging Dynamic braking Low average current density in brushes Contaminated atmosphere "Contact poisons" Oil on commutator or oil mist in air Abrasive dust in air Humidity too high Humidity too low Silicone contamination

DISTURBING EXTERNAL CONDITION 51.

52.

53.

54.

55.

56.

57.

58.

59.

60.

61.

62.

Loose or unstable foundation External source of vibration External short circuit or very heavy load surge "Commutation factor" too high "Commutation factor" too low Contact drop of brushes too high Contact drop of brushes too low Coefficient of friction too high Lack of film forming properties in brush Lack of polishing action in brush Brushes too abrasive Lack of carrying capacity

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DISASSEMBLY 1.

Remove the cover band from the commutator end of the motor (if equipped).

2.

Use a brush hook to reach into the motor and lift the brush springs. Pull the brushes out of the brush holders. Either position the brushes outside the motor or remove the brush retaining screws and remove the brushes from the motor.

3.

Scribe or center punch locating marks in the end head and the frame.

Although locating marks are not always necessary because of locating pins in some motors, they can save a lot of time when the motor does not have locating pins.

4.

Remove the commutator end head retaining screws. Almost all motors have a slip fit bearing at the commutator end, and the end head can be removed with very little trouble.

On motors that have a shaft extension on both ends of the armature, the attachment on the commutator end of the shaft must be removed before the end head can be separated from the motor.

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5.

6.

Remove the drive end head retaining screws, if necessary. Some of the smaller pump motors retain the drive end head with the motor through bolts. Separate the armature and drive end head as an assembly from the frame and field coil assembly.

Separate the armature from the drive end head. This operation is usually done by pressing the armature out of the drive end bearing. On some of the larger motors, the end head and bearing will have to be removed with a puller.

When a puller is used, protect the end of the armature shaft with a nut or a thick flat washer. If the shaft, coupling, or spline is damaged when removing the end head, the armature or the drive spline usually has to be replaced. Use caution and do not damage the armature.

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7.

Separate the bearing from the end head. On larger motors, the bearing is retained with a snap ring. Remove the snap ring. Then press the bearing out of the end head.

PRESSING END HEAD BACK ON ARMATURE SHAFT

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8.

The ventilation fans are cast aluminum. Once these fans have been pressed onto the armature, they must be heated to be removed without damage.

A puller is installed and a slight pressure exerted against the fan.

Use a small propane torch to heat the area of the fan around the shaft. When the fan becomes loose on the shaft, as evidenced by the puller becoming loose, it should be removed as quickly as possible.

9.

When the fan is reassembled on the shaft, make sure it is a tight fit.

Use "Loctite Retaining Compound 40" or equivalent on the inside of the fan hub when reassembling fan.

10.

After the motor has been separated into all its major subassemblies, the components should be cleaned and inspected for wear or damage.

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2.7.2 CONTROLLERS No internal repairs can be made to the transistor controllers. Contact the parts department for exchange units.

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4.0

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FRAME

FIGURE # 4.1 SHIELDS AND GUARDS

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4-2

FIG ITEM # # 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

# FOR ASSY.

NAME Screw, flat head Screw, button head Nut, clip Bracket, hitch Pad, platform Plate, platform Screw, socket head Angle, platform Cover Door, TMX Latch Plate, latch Screw, locking Cover, plate Screw, thread form Bumper, door Pad, knee Panel, backrest Cushion, backrest

4-3

13 3 3 1 1 1 4 1 1 1 1 1 2 1 2 2 1 1 1

FIGURE # 4.2 CONTROL HEAD ASSEMBLY WITH PICKING KNOB

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4-4

FIG ITEM # # 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2

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* 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

NAME

# FOR ASSY.

Handle With twist grip assembly Cover Spring Bracket Screw, thread form Pin, roll Cam Return Spring Housing, switch Bushing Shaft, cam Control, thumb Pin, threaded Block Coupler Pin, roll Grip, handle Pin Screw, socket (not part of handle assy.)

Knob assembly Shaft Ring, retainer Knob Screw, flat head Guard, wide Bolt, shoulder Pin, roll Potentiometer and wires Gear Bracket, potentiometer Screw, machine Switch, forward Spacer Switch, rearward Nut Lockwasher Bracket, forward & rearward Heater, freezer pkg.

Screw, flat head Cover Switch, horn Spring Bracket, switch Nut Clamp, cable Harness, wiring

1 1 4 1 6 3 1 1 1 1 2 1 2 2 2 2 2 2 2 2 2 1 1 1 8 1 1 1 1 1 1 2 1 1 1 2 2 1 1 9 1 1 2 1 1 1 1

4-5

4.3

SPECIFICATIONS Load wheel dimensions Drive tire dimensions

4.4

7x4 10.5 x 5 x 6.5 inches

MAINTENANCE AND ADJUSTMENTS Normal maintenance of the electric tow tractor frame consist of lubricating the transmission pivot bearing and the load wheels. See Planned Maintenance Schedule. In wet or corrosive environments it will be necessary to reduce the time between planned maintenance intervals.

4.5

TROUBLESHOOTING Very little troubleshooting is necessary on the frame assembly. Most faults can be found by visual inspection.

4.6

COMPONENT REMOVAL AND INSTALLATION 4.6.1 Control handle head Remove the six screws around the outer edge of the front switch bar cover on the control handle head. Do not remove the center screw. Lift the cover off. Remove two socket head screws accessible from inside the head assembly that bolt the head to the handle. Lift the head assembly away from the handle and disconnect the wiring harness plug before removing head from handle. Reassembly in reverse order.

4.6.2 LOAD WHEELS 1.

Park machine on level surface and disconnect battery.

2.

Jack machine high enough so that particular load wheel barely clears floor. Block machine securely.

3.

Remove socket screw, washer and string guard.

4.

Remove wheel, inner string guard and spacer.

5.

Remove bearings from wheel and grease fitting, replace bearings if damaged.

6.

Clean and re-pack bearings. Install bearing and grease fitting in new wheel.

7.

Clean axle and remaining parts. Replace if damaged.

8.

Install spacer and string guard on axle. Install wheel, outer string 4-6

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guard, washer, and socket screw. Torque to 75 to 80 foot pounds.

9.

Grease wheel, lower machine and check operation.

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THE PRIME-MOVER CO. 3000 NORTH US HIGHWAY 61 MUSCATINE, IOWA 52761-5810

PROUDLY Made in AMERICA

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