4-50. TRACTION MOTOR BRUSHES AND BRUSH HOLDERS
This task covers:
Tool kit SC4940-97-CL-E16
1/8 inch (3.17 mm) diameter drill rod
Small spring scale
(Item 27, Appendix E)
The traction motor can use two types of brushes. One is all carbon; the other is metal sheaved.
1. Inspect carbon brushes for more than 1/8 inch (3.2 mm) clearance between spring fingers and brush holder
Inspect metal-sheaved brushes for more than 1/4 inch (6.4 mm) clearance between end of brush and metal
Use spring scale and check for spring tension of between 8 and 10 pounds (3.6 and 4.5 kg).
Make sure brushes are not sticking, oily, or broken.
Make sure there is a clearance of 1/8 inch (3.2 mm) between brush holder and commutator.
6. If required disconnect latch (1) and remove top cover (2). Remove four capscrews (3) and lockwashers (4) and
remove bottom cover (5).
If only the brushes are unserviceable, they can be
replaced without removing the brush holders.
Remove screw (6), lockwasher (7), and flat washer (8). Release spring (9) and remove brushes (10).
If required disconnect electrical lead from brush holder (14). Remove bolt (11), lockwasher (12), and clamp (13).
Remove brush holder.