Starter Armature: Testing and Inspection

Armature




- Inspect commutator for dirt or burn. Correct with sandpaper or lathe, if necessary.




- Check commutator for uneven wear with armature (1) supported on V-blocks (2). If deflection of dial gauge (4) pointer exceeds limit, repair or replace.

NOTE: The following specification presupposes that the armature is free from bend. Bent armature must be replaced.

Commutator out of round
Standard: 0.05 mm (0.002 in.) or less
Limit: 0.4 mm (0.015 in.)




- Inspect the commutator for wear. If diameter is below limit, replace the armature.

Commutator outside diameter
Standard: 29.4 mm (1.16 in.)
Limit: 28.8 mm (1.13 in.)




- Inspect the commutator (1) for insulator (2) depth. Correct or replace if below limit.

Commutator insulator depth "a"
Standard: 0.4 - 0.6 mm (0.015 - 0.024 in.)
Limit: 0.2 mm (0.008 in.)




- Check the commutator and armature core. If there is continuity, the armature is grounded and must be replaced.




- Check for continuity between segments. If there is no continuity at any test point, there is an open circuit and the armature must be replaced.