4-46. TRACTION MOTOR BRUSHES AND BRUSH HOLDERS
This task covers:
Tool kit SC4940-97-CL-E16
1/8-inch (3.2 mm) diameter
Small spring scale
drill rod (Item 21, Appendix E)
Remove rings, bracelets, wristwatches, and neck chains before working around the
locomotive. Jewelry can catch on equipment and cause injury, or may short across an
electrical circuit and cause severe burns or electrical shock.
High voltage is used in the operation of equipment. Do not be misled by the term LOW
VOLTAGE. Potentials as low as 50 volts may cause death.
There are two commutator inspection plates or covers. Two covers are located on the side of
the motor. The covers are secured with latches. Brushes can be replaced without removing
The traction motor uses carbon brushes.
Open electrical equipment cabinet door and set battery switch to OPEN
Check for sticking, broken, or cracked brushes. Check carbon brushes for wear more than 3/4 inch (19 mm)
below top of brush holder. Check metal sheaved brushes for wear of more than 1/2 inch below top of brush
holder. Replace brushes, if either of these limits will be reached before next inspection
Use spring scale and check spring for spring tension of between 7.9 and 8.5 pounds (3.6 and 3.7 kg).