SHAFT 4491781 - Caterpillar

Illustration 1 g02222375
PMPE Generator Wiring Diagram for 1800 Frame Family (CR1-C6) Diodes (CR7) Varistor (L1) Exciter stator (L2) Exciter rotor (L3) Main rotor (L4) Main stator (L5) PMG stator (PM) Permanent magnet (RFA) Rotating field assembly (CT1) Optional voltage droop transformer (T0, T1, T2, T3, T7, T8, T9) Generator terminals
Table 1
Quantity     Needed Tool    
1     Low Ohmmeter    Measure the resistance of the following windings: (L1) , (L2) , (L3) , (L4) and (L5) . The winding that is being tested must be disconnected from the other components before the resistance can be measured. Note: The winding temperature affects the resistance. When the winding temperature increases, the winding resistance increases. When the winding temperature decreases, the winding resistance decreases. Therefore, a correct measurement can be performed only when the winding is at the ambient temperature.The following resistance measurements are approximations. If the measured value is not near the listed approximation, the winding is probably damaged. For a more precise resistance value, consult the Technical Marketing Information (TMI). Refer to the generator arrangement that is in question.The following windings have little resistance: (L2) , (L4) and (L5) . The resistance of these windings will measure near 0 ohms. Use a milliohmmeter to measure the resistance of the windings.Exciter Rotor (L2) - .05 to .06 ohmMain Stator (L4) - less than 0.1 ohmPilot Exciter Stator (L5) - less than 0.1 ohmUse a multimeter in order to measure the resistance of field windings (L1) and (L3) .Exciter Field (Stator) (L1) - Approximately 10 to 11 ohmsMain Field (Rotor) (L3) - Approximately 0.35 ohms to 1.2 ohmsNote: There should be no continuity between any winding and ground. There should be no continuity between any winding and another winding.