XQ175 Rental Generator Set Caterpillar

Initial Start-Up

Measure the insulation resistance of each winding if the generator was exposed to the following conditions:

• Rapid changes in temperature

• Freezing

• Wet climate during shipment

• Wet climate during storage

Refer to this Operation and Maintenance Manual, "Insulation - Test".

Note: These tests should be conducted prior to any power connections or control connections that are being made.

Starting

1. Make all preliminary engine starting checks.

2. Be sure that the main circuit breaker or the line circuit breaker is open.

3. Start the engine. Allow the engine to warm up.

4. Adjust to the full load engine speed.

5. Close the main circuit breaker.

6. Apply the load. Do not try to apply the full load. Apply the load in increments in order to maintain system frequency at a constant level.

7. Readjust the governor for rated frequency.

Adjust the Voltage

Adjust the voltage regulator in order to obtain the proper voltage. Refer to Operation and Maintenance Manual, "Voltage Regulators" for more information about the voltage regulator.

1. Turn the remote adjustment potentiometer to the center position, if equipped.

2. Connect an analog voltmeter that is calibrated for 100 VDC on terminal E+ and terminal E-.

3. Connect a voltmeter that is calibrated for 300 VAC to 500 VAC or 1000 VAC to the output terminals of the generator.

4. Make sure that the ST3 wire is positioned on the desired frequency. Also, the engine speed must be changed from the factory setting in order to change the frequency of the generator.

5. Turn voltage potentiometer (P2) to a full counterclockwise position.

6. Turn frequency potentiometer (P4) to a full clockwise position.

7. Turn stability potentiometer (P3) counterclockwise to about 1/3 of the total rotation for the potentiometer.

8. Start the engine and set the engine speed to a frequency of 48 Hz for 50 Hz or 58 Hz for 60 Hz.

9. Adjust the output voltage to the correct value with potentiometer P2. This voltage should be the rated voltage UN for single operation or UN plus 2% to 4% for parallel operation with a current transformer. Use potentiometer P3 to make adjustments if the voltage oscillates. Adjust potentiometer P3 in both directions while you observe the voltage between E+ and E-. The voltage between E+ and E- should be approximately 10 VDC. The best response times are obtained at the limit of the instability. Try cutting or replacing the wire ST2 if no stable position can be obtained.

10. Check the LAM operation. ST5 must be closed.

11. Turn potentiometer (P4) slowly counterclockwise until there is a significant voltage drop. The voltage drop should be approximately 15 %.

12. Vary the frequency around 48 Hz or 58 Hz according to the operating frequency. Check the change in the voltage that was previously observed.

Stopping

1. Remove the load in increments.

2. Open the circuit breaker.

3. Allow the engine to run for five minutes in order to cool.

4. Stop the engine.