Caterpillar — Poor Voltage Regulation - 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
- Verify the voltage regulator chassis is properly grounded at terminal P6-6.
- Check for grounded field leads; isolate from ground if found.
- Check for grounded PMG leads; isolate from ground if found.
- Verify generator frequency is not dropping below the under frequency set point when load is applied.
- Verify regulation is not affected by normal droop operation.
- Verify regulation is not affected by normal line loss compensation; replace regulator if not.
- On new/commissioned applications, check the PID value; reduce Kg then Kp if voltage fluctuates at steady state.
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.