PUMP GP-PISTON 2578470 - Caterpillar

Illustration 1 g01388839
PMPE Generator wiring diagram for the family of 1800 frames
(CR1-C6) Diodes
(CR7) Varistor
(L1) Exciter stator
(L2) Exciter rotor
(L3) Main rotor
(L4) Main stator
(L5) Permanent magnet generator 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 room 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) - Refer to Table 2.Main 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) - Refer to table 2.Main 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.
Table 2
L1 Exciter Field L2 Exciter Rotor Main Field for the Rotor
1800 Frame 10.9 ohms 0.05 ohms .9 ohms
3000 Frame 9.6 ohms 0.043 ohms .84 to 1.4 ohms