ARMY TM 9-2815-255-24
AIR FORCE TO 38G1-95-2
MARINE CORPS TM 2815-24/4
FIGURE 3-16. Removing Brush Holder Assembly
3-12.4. Inspect and Measure/Repair.
Check armature commutator run-out as follows:
Place armature bearings on V-blocks.
Zero dial indicator on commutator.
Rotate armature and record run-out. Standard is 0.0008 inch (0.02 mm), with a limit of 0.00197 inch (0.5
If run-out exceeds limit, replace armature.
Using a micrometer, measure OD of commutator. If measurement is less than 1.38 inches (35 mm), replace
Measure commutator segment mica depth as shown in FIGURE 3-17. If depth is less than 0.0079 inch (0.2
mm), undercut the mica.
Check commutator surface for bum spots. This usually indicates an open circuit. Remove these spots using
#400 abrasive paper.
Inspect bearings (33 and 34, FIGURE 3-15) for wear and damage. If damaged or worn, replace bearings using a
FIGURE 3-17. Measuring Segment Mica Depth