Caterpillar VR6 — Knee Frequency - Adjust

Adjustments · VR6 voltage regulator

For the Caterpillar VR6, from the Caterpillar service manual.

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Procedure

1. Operation at 60 Hz: adjust generator frequency for 60 Hz.
2. Turn knee frequency adjustment fully counterclockwise or until voltage does not increase with further turning.
3. Turn voltage adjustment until voltage is 240 VAC on terminals 20, 22, and 24.
4. Slowly turn knee frequency adjustment clockwise until voltage begins to decrease.
5. Turn knee frequency adjustment counterclockwise until voltage just returns to 240 VAC.
6. Operation at 50 Hz: adjust generator frequency for 50 Hz.
7. Turn knee frequency adjustment fully counterclockwise or until voltage does not increase with further turning.
8. Turn voltage adjustment until voltage is 200 VAC on terminals 20, 22, and 24.
9. Slowly turn knee frequency adjustment clockwise until voltage begins to decrease.
10. Turn knee frequency adjustment counterclockwise until voltage just returns to 200 VAC.
11. Connect a jumper from terminal 8 to terminal 6A for 1 V/Hz underfrequency slope; no connection to terminal 8 results in 2 V/Hz slope.
12. Start generator; run at no load; decrease engine RPM and observe frequency at which voltage starts to decrease.
13. If knee frequency is lower than 5 Hz below rated frequency, readjust knee frequency.

Source: Caterpillar service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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