Bench Testing: Rotor

Using DVOM, measure the resistance between the slip rings. See Fig 1. If resistance is 2.5-2.9 ohms at 68°F (20°C), go to next step. If resistance is not 2.4-2.9 ohms at 68°F (20°C), replace rotor.
Using DVOM, verify there is no continuity between the slip ring and core. See Fig 2. If continuity does not exist, go to next step. If continuity exists, replace the rotor.
Inspect the slip ring surface condition. If slip ring surface is rough, use a lathe or fine sandpaper to repair.

Fig 1: Measuring Resistance Between Slip Rings (Typical)

Courtesy of SUBARU OF AMERICA, INC.

Fig 2: Checking For Continuity Between Slip Ring & Core (Typical)

Courtesy of SUBARU OF AMERICA, INC.