Alternator Components, Check
Check phases of stator winding for short circuit to ground.
Hold test probes of ohmmeter to bare metal point on stator housing and to each phase end.
Test value: infinite resistance.
If nominal value is not attained, replace stator completely.
Check phases of stator winding for passage with ohmmeter.
Measure resistance of two phases. Hold test probes alternately to winding ends.
Test value: Approx. 0.1 ohms at 20 �C/68 �F.
If nominal value is not attained, replace stator completely.
Check excitation winding for short circuit to ground with ohmmeter.
Touch probes to armature and slip ring.
Test value: infinite resistance.
If the field winding has a short circuit to ground, replace rotor completely.
Check field winding for passage with ohmmeter (see illus.).
Measure the winding resistance from slip ring to slip ring.
Nominal value: Approx. 3.6 ohms at 20 �C/68 �F.
If the nominal value is not attained, replace rotor.
Clamp rotor in lathe (see illus.) Clean and polish slip rings with fine emery cloth (P500-600).
If out-of-round, slip rings can be turned down to minimum dimension "I" = 30 mm/1.18 in.
When turning down, remove as little material as possible. Then polish and blow through slip rings.
If the slip rings are worn to below the minimum dimension "I" = 30 mm/1.18 in., replace rotor.