Caterpillar — No Voltage Droop - Troubleshoot

Testing & diagnosis · Cat Digital Voltage Regulator (CDVR)

From a Caterpillar service manual — check it applies to your exact model before use.

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Procedure

1. Verify the voltage regulator is programmed for droop mode.
2. Verify the droop setting is not adjusted to 0%; increase above 0% if so.
3. Check for an open circuit at terminals P12-1, P12-2 and CT2.
4. Verify connections are correct and CT/PT are not installed backwards or on the wrong phase.
5. Verify the test load is not purely resistive; apply an inductive load and retest.
6. Verify the current sensing transformer is compatible (regulator has a 5 A CT input).
7. Check wiring to the programmable switch input if configured for line loss compensation.
8. Replace the voltage regulator if all prior steps fail to correct the malfunction.

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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