ROTOR
Using a DVOM, check for continuity between rotor slip rings. Ensure continuity is present. Replace rotor assembly if continuity is not present. Check for continuity between any rotor slip ring and rotor core. Continuity should not be present. Replace rotor assembly if continuity is present. Ensure slip ring diameter exceeds minimum specification. See SLIP RING MINIMUM DIAMETER table.
| Application | In. (mm) |
|---|---|
| Hitachi | 1.024 (26.0) |
| Mitsubishi | .870 (22.1) |
SLIP RING MINIMUM DIAMETER
STATOR
Using a DVOM, check for continuity between stator core leads. Ensure continuity is present. If continuity is not present, replace stator. Check for continuity between stator core and each stator lead. Continuity should not be present. If continuity is present, replace grounded stator.
DIODES
Note. Separate stator and diode assembly by unsoldering connecting wires. Use just enough heat to melt solder. Excessive heat will damage diodes.
Using DVOM, connect positive lead to positive diode plate, and negative lead to any diode terminal. Reverse test leads. Continuity should exist in only one direction. Repeat test procedure for each remaining diode. If continuity exists in both directions, or continuity does not exist in either direction, replace entire diode assembly.
BRUSHES
Inspect brushes for free movement in holder. Clean brush holder if necessary. Check brushes for cracks and wear. Check brush springs for corrosion or damage. Ensure brushes are not worn beyond minimum length (limit mark scribed on brush). If brushes do not have scribed minimum length mark, ensure brush length exceeds minimum specification. See MINIMUM BRUSH LENGTH table.
| Application | In. (mm) |
|---|---|
| Hitachi | .236 (6.0) |
| Mitsubishi | .197 (5.0) |
MINIMUM BRUSH LENGTH