VR6 Voltage Regulator Caterpillar

Illustration 1	g00779342
VR6 Voltage Regulator (1) Knee frequency adjustment (2) Voltage adjustment

Illustration 2	g01021519

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The Cat VR6 presents an electrical shock/electrocution hazard. This hazard will cause serious injury or death. Service by trained personnel only. The terminals and heat sinks are live at hazardous voltages when power is applied and for up to 8 minutes after power is removed.

Operation at 60 Hz

1. Adjust the generator frequency for 60 Hz.

2. Turn the knee frequency adjustment (1) fully counterclockwise (CCW) or until voltage does not increase with further turning.

3. Turn the voltage adjustment (2) until the voltage is at 240 VAC on terminals 20, 22, and 24.

4. Slowly turn the knee frequency adjustment (1) clockwise (CW) until the voltage begins to decrease.

5. Turn the knee frequency adjustment (1) CCW until the voltage just returns to 240 VAC. The knee frequency is now set just below the nominal operating frequency.

   Note: Further rotation in the CCW direction will lower the frequency at which underfrequency compensation begins.

6. Connect a jumper from terminal 8 to terminal 6A in order to provide an underfrequency slope of 1 V/Hz. No connection to terminal 8 will result in an underfrequency slope of 2 V/Hz.

7. Start the generator.

8. Run the generator at no load.

9. Decrease the engine RPM and observe the frequency at which the voltage starts to decrease. If the knee frequency is lower than 5 Hz below the rated frequency, readjust the knee frequency.

Operation at 50 Hz

Illustration 3	g01021519

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The Cat VR6 presents an electrical shock/electrocution hazard. This hazard will cause serious injury or death. Service by trained personnel only. The terminals and heat sinks are live at hazardous voltages when power is applied and for up to 8 minutes after power is removed.

1. Adjust the generator frequency for 50 Hz.

2. Turn the knee frequency adjustment (1) fully counterclockwise (CCW) or until voltage does not increase with further turning.

3. Turn the voltage adjustment (2) until the voltage is at 200 VAC on terminals 20, 22, and 24.

4. Slowly turn the knee frequency adjustment (1) clockwise (CW) until the voltage begins to decrease.

5. Turn the knee frequency adjustment (1) CCW until the voltage just returns to 200 VAC. The knee frequency is now set just below the nominal operating frequency.

   Note: Further rotation in the CCW direction will lower the frequency at which underfrequency compensation begins.

6. Connect a jumper from terminal 8 to terminal 6A in order to provide an underfrequency slope of 1 V/Hz. No connection to terminal 8 will result in an underfrequency slope of 2 V/Hz.

7. Start the generator.

8. Run the generator at no load.

9. Decrease the engine RPM and observe the frequency at which the voltage starts to decrease. If the knee frequency is lower than 5 Hz below the rated frequency, readjust the knee frequency.