Rotor Assembly

Inspect the slip rings for contamination or any roughness on the sliding surface.
Measure the slip ring outer diameter.
Slip ring outer diameter:

Standard

14.2 - 14.8 mm (0.559 - 0.583 in)

Limit

14.0 mm (0.551 in)
Check the resistance between slip rings.
Specification:

Approx. 2.0 - 2.4 Ω

Fig 1: Checking Resistance Between Slip Rings
Courtesy of SUBARU OF AMERICA, INC.
Check insulation between slip ring and rotor core or shaft. Replace the rotor assembly if continuity exists.

Fig 2: Checking Insulation Between Slip Ring And Rotor Core
Courtesy of SUBARU OF AMERICA, INC.
Check the ball bearings (rotor side). Check the following items and replace the rotor assembly if necessary.
- Check that there is no deformation, rust or other damages.
- Check that there is no resistance or looseness when rotating the ball bearings by hand.
- Check for grease leakage.