Rotor check
1. Check for an open in the field winding.
Using an ohmmeter, measure the resistance between the slip rings.
- Rated resistance - 3.9 - 4.1 Ohm
If resistance goes to infinity (those. open circuit) - replace the rotor.
2. Check if the excitation winding is shorted to "mass".
Using an ohmmeter, measure the resistance between the rotor pole and the slip ring.
If resistance is 0 (circuit is closed), then replace the rotor.
3. Check slip rings.
A) Check the working surfaces of the slip rings. They should not have scuffs or chips.
b) Using a caliper, measure the diameter of the slip rings.
- Nominal diameter - 32.3 - 32.5 mm
- Minimum allowable - 32.1 mm
If the diameter of the slip rings is less than the minimum allowable, then replace the rotor.
Stator check
1. Check for an open in the stator winding.
Using an ohmmeter, measure the resistance between the terminals of the stator winding coils.
If resistance goes to infinity (those. open circuit) - then replace the stator.
2. Check if the stator winding is shorted to "mass".
Using an ohmmeter, measure the resistance between the stator housing and the stator coil leads.
If the resistance is "0" (those. circuit is closed) - then replace the stator.