SRMP Electric Power Generation SRMP Generator Caterpillar

Illustration 1	g00874841
PMG Generator Wiring Diagram (CR1-C6) Diodes (CR7) Varistor (L1) Exciter Field (Stator) (L2) Exciter Armature (Rotor) (L3) Main Field (Rotor) (L4) Main Armature (Stator) (L5) Pilot Exciter Armature (PM) Permanent Magnet (RFA) Rotating Field Assembly (CT1) Optional Voltage Droop Transformer (T0, T1, T2, T3, T7, T8, T9) Generator Terminals

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 armature windings havevery 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 armature windings.

Exciter Armature (Rotor) (L2) - less than 0.1 ohm

Main armature (Stator) (L4) - less than 0.1 ohm

Pilot Exciter Armature (L5) - less than 0.1 ohm

Use a multimeter to measure the resistance of field windings (L1) and (L3).

Exciter Field (Stator) (L1) - approximately 3.0 ohms to 6.0 ohms

Main Field (Rotor) (L3) - approximately 0.75 ohms to 2.0 ohms

Note: There should be no continuity between any winding and ground. There should be no continuity between any winding and another winding.