Rotor: Testing and Inspection

INSPECTION

ROTOR

1. Slip ring surface
Inspect slip rings for contamination or any roughness of the sliding surface. Repair slip ring surface using a lathe or sand paper.

2. Slip ring outer diameter
Measure slip ring outer diameter. If slip ring is worn, replace rotor assembly.

Slip ring outer diameter:
Standard 22.7 mm (0.894 in)
Limit 22.1 mm (0.870 in)




3. Continuity test
Check resistance between slip rings using circuit tester.
If the resistance is not within specification, replace rotor assembly.




4. Insulation test
Check resistance is 1 Ohm or less between slip ring and rotor core or shaft. If resistance is 1 Ohm or less, the rotor coil is grounded, and so replace rotor assembly.




5. Ball bearing (rear side)
1. Check rear ball bearing. Replace if it is noisy or if rotor does not turn smoothly.
2. The rear bearing can be removed by using common bearing puller.