Starter Armature: Testing and Inspection

Armature Inspection:

1. Inspect the armature for wear or damage due to contact with the field coil magnets.

Checking The Commutator Diameter:

Commutator Diameter Specifications:

2. A dirty or burnt commutator surface may be resurfaced with emery cloth or a lathe within the following specifications.

Checking The Commutator Runout:

Commutator Runout Specifications:

3. If the commutator runout and diameter are within limits, check the commutator for damage or for carbon dust or brass chips between the segments.

Cleaning Up The Commutator Surface:

4. If the surface is dirty, recondition it with a #500 or #600 sandpaper.

Mica Depth Check:

Commuter Mica Depth Specification:

5. Check for mica depth. If necessary, undercut mica with a hacksaw blade to achieve proper depth.

Commutator Continuity Check:

6. Check for continuity between each segment of the commutator. If an open circuit exists between any segment, replace the armature.

Armature Testing:

7. Place the armature on an armature tester. Hold a hacksaw blade on the armature core. If the blade is attracted to the core or vibrates while the core is turned, the armature is shorted. Replace the armature.

Commutator And Armature Continuity Check:

8. Check with an ohmmeter that no continuity exists between the commutator and armature coil core, and between the commutator and armature shaft. If continuity exists, replace the armature.