Section 93 (Starting System & Charging System (H4DO)): Generator: Inspection: Rotor

WARNING: This page is about a different car, the 2012 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.

Slip ring surface
Inspect the slip rings for contamination or any roughness on the sliding surface. Repair the slip ring surface using a lathe or sand paper.
Slip ring outer diameter
Measure the slip ring outer diameter. Replace the rotor if the slip ring is worn.

Slip ring outer diameter:

Standard

22.7 mm (0.894 in)

Limit

22.1 mm (0.870 in)
Continuity test
Using a circuit tester, check the resistance between slip rings. If the resistance is not within the standard, replace the rotor.

Standard:

Approx. 2.0 - 2.4 Ω

Fig 1: Checking Resistance Between Slip Rings Using Circuit Tester
Courtesy of SUBARU OF AMERICA, INC.
Insulation test
Check the continuity between slip ring and rotor core or shaft. If there is continuity, replace the rotor because the rotor coil is grounded.

Fig 2: Checking Continuity Between Slip Ring, Rotor Core And Shaft
Courtesy of SUBARU OF AMERICA, INC.
Bearing
Check the bearings. If there is any noise, or the rotor does not rotate smoothly, replace the bearings.