Rotor: Testing and Inspection
ROTOR1. Slip ring surface:
Inspect the slip rings for contamination or any roughness of the sliding surface. Repair the slip ring surface using a lathe or sand paper.
2. Slip ring outer diameter:
Measure the slip ring outer diameter. If the slip ring is worn replace the rotor assembly.
Slip ring outer diameter:
Standard 22.7 mm (0.894 in)
Limit 22.1 mm (0.870 in)
3. Continuity test:
Check the resistance between slip rings using a circuit tester.
If the resistance is not within specification, replace the rotor assembly.
4. Insulation test:
Check the continuity between slip ring and rotor core or shaft. If the resistance value is below 1 Ohm, the rotor coil is grounded, and so replace the rotor assembly.
5. Ball bearing (rear side):
1. Check the rear ball bearing. Replace if it is noisy or if the rotor does not turn smoothly.
2. The rear bearing can be removed by using a common bearing puller.