FIRE EXTINGUISHER GP 1871517 - Caterpillar

Illustration 1 g02222375
PMPE Generator wiring diagram (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
TOOLS NEEDED    
Quantity     Part Number     Description    
1     142-5055     Insulation Tester
Megohmmeter    
Personal injury or death can result from electrocution.The megohmmeter is applying a high voltage to the circuit.To avoid electrocution, do not touch the instrument leads without first discharging them. When finished testing also discharge the generator windings.
The following materials will cause the winding insulation to deteriorate:
Moisture (water)
Dust
Grease
Other foreign matter within the generatorThis deterioration reduces the resistance of the insulation. This test will measure the resistance of the winding insulation. The insulation tester (megohmmeter) produces a high potential voltage between the test leads. A small current will flow during the test. The tester converts this current to a resistance reading.The insulation test is performed as part of periodic maintenance in order to detect the deterioration of the winding insulation. When there is a rapid decrease in the insulation resistance in a short amount of time, the generator needs to be cleaned.Note: For information on generator cleaning, refer to Special Instruction, SEHS9124.Moisture can accumulate in generators that have not been in use. The insulation test should be performed on generators that have been idle. If moisture is known to exist, the windings must be dried prior to testing. Refer to the Testing and Adjusting, "Generator - Dry" section of this publication.After the windings are cleaned and dried, the windings must be reconditioned or replaced if the measured insulation resistance falls below the specified amount.The specified insulation resistance is an approximate value. The generator can be operated with less than the specified value. However, a generator that has a low winding insulation resistance will be more likely to have a failure.
Personal injury or death can result from improper troubleshooting and repair procedures.The following troubleshooting and repair procedures should only be performed by qualified personnel familiar with this equipment.
The insulation test gives accurate results only when the generator windings are free of moisture and the generator windings are at ambient temperature.The rule in this paragraph applies to generators with rated voltage of 1 kV or less. If the insulation resistance test shows a reading of less than 1 megohm of resistance, a substantial loss of insulation capacity has occurred. The unit should not be started and should be removed for cleaning and drying.Use the following formula to determine the absolute minimum resistance value for generators with rated voltage of 1 kV or more.
Illustration 2 g02352787
Main Stator L4
Remove the load from the generator by either opening the line circuit breaker or the load connections to (T1) , (T2) , (T3) , and (T0) . Prevent these wires from coming into contact with each other and prevent these wires from contacting ground.
Isolate main stator (L4) from the voltage regulator by disconnecting the voltage