SR4 HV and SR4B HV Generators Caterpillar

Illustration 1	g00935076
PMPE Generator Wiring Diagrams for 2400, 2500, 2800, and 2900 frames (CR1-CR6) 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 (CST) Customer supplied transformer (B) External 12 Volt DC Power Source

Illustration 2	g00935050
PMPE Generator Wiring Diagrams for 2600 frames (CR1-CR6) 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 (CST) Customer supplied transformer (B) External 12 Volt DC Power Source

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Dangerous voltages are present at both the generator and the system bus. Under no circumstances should any attempt be made to connect instrumentation to these points until you are certain all power is off. All instruments must be connected to the generator and the system bus through potential transformers, which provide a maximum of 600 volts to the instruments. Failure to follow instructions will result in death or serious injury.

Dangerous voltages are present at the generator's output terminals. Until the power is verified to be OFF, there should not be any device that is connected to the following terminals: (T1), (T2) and (T3). The voltmeter must be connected to the generator through potential transformers. Potential transformers provide a maximum of 600 volts to the voltmeter.

The generator set functional test is a simplified test that can be performed in order to determine if the generator is functional. The generator set functional test should be performed on a generator set that is under load.

The generator set functional test determines if the following statements happen:

• A phase voltage is being generated.

• The phase voltages are balanced.

• The phase voltages change relative to engine speed.

The generator set functional test consists of the following steps:

1. Stop the generator. Connect the potential transformer's high voltage winding to the generator terminals (T1) and (T2). Connect the voltmeter to the low voltage winding. If two transformers are available, connect the high voltage winding of the second transformer to the generator terminals (T1) and (T3). Connect the secondary terminals that correspond to generator terminal (T2) of both transformers together.

2. Disconnect wires "F1+" and "F2-" from the voltage regulator. Disconnect the generator from the load.

3. Connect a 12 Volt DC power source to wires "F1+" and "F2-"for 2600 frames. Connect a 12 Volt DC power source to wires "F1-" and "F2+"for all other frames.

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NOTICE
Do not operate the generator set at a speed that is higher than one-half of the rated speed. Higher speeds under these test conditions can cause damage to the system.

4. Operate the generator set at half the rated speed.

5. Measure the AC voltage across the low voltage terminals of the transformer that correspond to the following generator terminals: "T1" and "T2", "T2" and "T3" and "T3" and "T1". Record the voltages.

6. Monitor the voltage between any two of the locations in step 5. Decrease the generator set speed by 10%. Increase the generator set speed by 10%.

7. The voltages that were measured in Step 5 should be nearly equal. These voltages should measure a minimum of 85 VAC.

8. When the generator set speed is decreased by 10%, the voltages that were measured in Step 6 should decrease by 10%. When the generator set speed is increased by 10%, the voltages that were measured in Step 6 should increase by 10% .