Caterpillar — Adjustments for Crosscurrent Compensation

Adjustments · Voltage regulator / crosscurrent compensation

From a Caterpillar service manual covering: APM 300, SR4, VR3. Check it applies to your exact model before use.

Applies to: Caterpillar SR4

Procedure

1. Adjust governor setting for proper kW balance before attempting to adjust reactive kVAR unbalance (kW load sharing is a function of the engine governor only).
2. Turn the gain potentiometer to the full CCW position.
3. Turn the droop potentiometer to the full CCW position.
4. On each generator, adjust the voltage level potentiometer to the rated no load voltage.
5. Apply full rated load with 0.8 pf to the individual generator.
6. Adjust the gain potentiometer to compensate for voltage drop due to governor speed droop at rated load, if the governor is not isochronous.
7. Adjust the droop potentiometer to obtain 5% droop when operating as a single unit at full load 0.8 pf.
8. Remove the load.
9. Parallel the generators at no load and adjust for minimum circulating current, if any, using the voltage level potentiometer.
10. Apply full rated resistive and reactive loads.
11. Adjust to minimum circulating current using the droop potentiometer.

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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