Bench Testing: Armature
- Inspect commutator for dirt or burn spots. Correct with sandpaper or lathe as necessary.
- Using DVOM, check for grounded circuit. Check for continuity between commutator and armature coil core. See Fig 1. Continuity should not be present between commutator and armature coil core. If continuity exists, replace armature.
- Using DVOM, check for an open circuit. Check for continuity between each individual commutator segment at commutator end of armature. See Fig 1. Continuity should exist between each individual commutator segment. Replace armature if continuity does not exist between any 2 segments.
- Support armature between "V" blocks. Using dial indicator, check armature runout at commutator end of armature. Normal armature runout should be less than .002" (.05 mm). Replace armature if armature runout exceeds .015" (.40 mm).NOTE: Bent commutator/armature must be replaced.
- Using caliper, measure commutator outside diameter at center of commutator. Replace armature if commutator outside diameter is not within specification. See STARTER SPECIFICATIONS .
- Measure insulator depth at grooves between commutator segments. See Fig 2. Replace armature if insulator depth is not within specification. See STARTER SPECIFICATIONS .