Inspection

1. ARMATURE
1. Check commutator for any sign of burns of rough surfaces or stepped wear. If wear is of a minor nature, correct it by using sand paper.




2. Run-out test
Check the commutator run-out and replace if it exceeds the limit.
Commutator run-out:
Standard
0.02 mm (0.0008 in), or less
Service limit
Less than 0.05 mm (0.0020 in)




3. Depth of segment mold
Check the depth of segment mold.
Depth of segment mold:
0.6 mm (0.024 in)
Limit
0.2 mm (0.008 in)




4. Armature short-circuit test
Check armature for short-circuit by placing it on growler tester. Hold a hacksaw blade against armature core while slowly rotating armature. A short-circuited armature will cause the blade to vibrate and to be attracted to core. If the hacksaw blade is attracted or vibrates, the armature, which is short-circuited, must be replaced or repaired.




5. Armature ground test
Using circuit tester, touch one probe to the commutator segment and the other to shaft. There should be no continuity. If there is a continuity, armature is grounded.
Replace armature if it is grounded.




2. YOKE
Make sure pole is set in position.




3. OVER RUNNING CLUTCH
Inspect teeth of pinion for wear and damage.
Replace if it is damaged. Rotate pinion in direction of rotation (clockwise). It should rotate smoothly.
But in opposite direction, it should be locked.

CAUTION: Do not clean overrunning clutch with oil to prevent grease from flowing out.

4. BRUSH AND BRUSH HOLDER




1. Brush length
Measure the brush length and replace if it exceeds the service limit.
Replace if abnormal wear or cracks are noticed.
Brush length:
Standard
15 mm (0.59 in)
Service limit
10 mm (0.39 in)

2. Brush movement
Be sure brush moves smoothly inside brush holder.




3. Insulation resistance of brush holder Be sure there is no continuity between brush holder and its plate.

4. Brush spring force
Measure brush spring force with a spring scale. If it is less than the service limit, replace brush spring.

Brush spring farce:
Standard
18.6 N (1.9 kg, 4.2 lb) (when new)
Service limit
6.9 N (0.7 kg, 1.5 lb)

5. BEARING
1. Rotate bearing by hand; no binding should exist.




2. Rotate bearing rapidly; no abnormal noise should be heard.