Rotor Assembly
- Check slip ring surfaces for contamination or roughness. If roughened, sand surface of slip rings with fine sand paper. If contaminated, clean with cloth saturated with alcohol.
- Measure outside diameter of slip rings. Replace rotor if slip ring diameter is not between 1.18-1.24" (30-31.5 mm).
- Connect ohmmeter leads to each slip ring. See Fig 1. Resistance should be 4.2 ohms at 68°F (20°C). If no continuity exists, coil is open and rotor assembly must be replaced.
- If resistance is substantially lower than specification, coil is shorted and rotor assembly must be replaced.
- Connect ohmmeter leads to either slip ring and rotor core. See Fig 2. If continuity exists, coil is grounded and rotor assembly must be replaced.
- Check front and rear bearings for wear or roughness and replace if necessary.