Starter Armature: Testing and Inspection

Armature Inspection And Test:

1. Inspect the armature for wear or damage due to contact with the permanent magnet. If there is wear or damage, replace the armature.

Armature Inspection And Test:

2. Check commutator surface and diameter.

If the surface is dirty or burnt, resurface with emery cloth or a lathe within the following specifications, or recondition with #500 or #600 sandpaper.

- If commutator diameter is below the service limit, replace the armature.

Armature Inspection And Test:

Commutator Diameter:
Standard (New): 28.0 - 28.1 mm
Service Limit: 27.5 mm

3. Measure the commutator runout.
- If the commutator runout is within the service limit, check the commutator for carbon dust or brass chips between the segments.
- If the commutator runout is not within the service limit, replace the armature.

Armature Inspection And Test:

Commutator Runout:
Standard (New): 0.0 - 0.02 mm
Service Limit: 0.05 mm

4. Check the mica depth. If necessary, undercut the mica with a hacksaw blade to achieve proper depth. If the service limit cannot be maintained, replace the armature.

Armature Inspection And Test:

Commutator Mica Depth
Standard (New): 0.4 - 0.5 mm
Service Limit: 0.15 mm

Armature Inspection And Test:

5. Check for continuity between the segments of the commutator. If an open circuit exists between any segments, replace the armature.

Armature Inspection And Test:

6. 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.

Armature Inspection And Test:

7. 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.