Component Testing: Commutator

Inspect commutator segments for roughness, grooves, burns or pitting. If necessary, sand lightly with 500-600 grit crocus cloth. Check commutator for out-of-round and for mica insulators proper undercut depth. Mica depth between commutator segments may be undercut as per specifications. See STARTER SPECIFICATIONS  table. Replace armature if commutator is excessively worn.