Model 6210 Maintenance Manual
Section 7. Component Procedures
Electrical Components
DC Motors, General
Terminal Nuts
Polishing the Commutator
Do not attempt to repair power cable terminal lugs without approved tools. If a power cable has worn or damaged lugs, either replace the cable or replace the lugs using the procedure described in “Power Cable Repair” on page 7-45. Do not substitute other kinds of nuts for the flanged nuts. Failure to use correct cables, flanged nuts, and torque values can result in overheating and damage to components. Figure 7-74.
Motor Terminal Nuts
Terminal Stud Motor Cable Securing Nut
Split Lock Washer
Stud Terminal Securing Nut
Motor Housing
NOTE: Wrap the stone with narrow (1/2 to 3/4 inch wide) masking tape in a spiral configuration. Leave only enough stone exposed to make contact with the commutator. As the length of the stone becomes shorter with use, peel back and remove portions of the tape.
Make sure loose clothing and hair are tied back. Do not wear jewelry. Wear insulated gloves to protect your hands during this procedure. 1. If the motor has four or more brushes, remove an accessible brush from the motor with the motor still installed in the truck. If the motor only has 2 brushes or the commutator is not accessible with the stone, the armature must be installed in a lathe or replaced. If so, go to step 4. 2. Activate the motor.
Whenever you disconnect and reconnect any power cables to the motors or traction amplifier, always tighten the cable securing nuts with a torque wrench to prevent over-tightening them and damaging the motor or traction amplifier. Check these torques each time you check the motors and the traction amplifier. Use two wrenches to avoid twisting the terminal stud. See Figure 7-74. Stud Size
Motor Cable Securing Nut
3/8 in. (M10)
60 to 84 in. lb. (6.8 to 9.5 Nm)
Publication: 1146947, Revised: 12 Jan 2017
3. With the motor turning, carefully insert the commutator stone into the brush box area. 4. Using minimal pressure, run the stone back and forth across the commutator until it is polished. Do not pass the stone over the ends of the commutator segments. 5. Thoroughly blow out the motor with compressed air. 6. Inspect the commutator. Reinstall the armature or brush and any removed covers. 7. Check operation.
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