Cummins

81 O

UnclassifiedElectrical

What This Code Means

Generator set is operating at a potentially damaging frequency level; Over frequency shutdown; Over frequency warning; Generator set shutdown; Output voltage on any phase exceeds preset values; Voltage on any phase drops below preset value; Generator set output frequency cannot be maintained; Generator set warning; Generator set operating at potentially damaging frequency level; Instantaneous tripping (50mS response to turn off AVR excitation/shutdown generator set); 1-Phase short circuit; 2-Phase short circuit; 3-Phase short circuit; Output voltage on any phase exceeds preset values (105-125% of nominal); Voltage on any phase has dropped below a preset value (50-95% of reference); Generator set output frequency cannot be maintained (2-10 Hz below reference governor set point); 3-Phase short circuit (thermal damage); Voltage on any phase has dropped below a preset value; Over frequency shutdown/warning

Possible Causes

  • •Generator frequency exceeds nominal governor set point by 2-10 Hz for a 1-20 second time delay
  • •Output voltage on any phase exceeds preset threshold (105-125% of nominal voltage)
  • •Voltage on any phase drops below preset threshold (50-95% of reference voltage)
  • •Generator set output frequency drops below reference governor set point (2-10 Hz below)
  • •Generator set is operating at a potentially damaging frequency level
  • •AmpSentry Maintenance Mode (AMM) is active for arc flash reduction when personnel are near the generator set
  • •Fault conditions in the generator set or in the load
  • •Generator frequency exceeds nominal governor set point (by 2-10 Hz)
  • •High AC voltage
  • •Low AC voltage
  • •Under frequency
  • •Over frequency
  • •Short circuit
  • •Voltage on any phase exceeds preset threshold (adjustable from 105 - 125% of nominal voltage)
  • •Voltage on any phase drops below preset threshold (adjustable over a range of 50 - 95% of reference voltage)
  • •Output frequency drops below reference governor set point by adjustable range of 2 - 10 Hz
  • •Generator set is operating above nominal governor set point by adjustable range of 2 - 10 Hz
  • •Generator set operating at 2 - 10 Hz above nominal governor set point

Suggested Actions

  1. 1Adjust over frequency settings (adjustable from 2-10 Hz above nominal governor set point for a 1-20 second time delay)
  2. 2Adjust high AC voltage threshold setting (adjustable from 105-125% of nominal voltage)
  3. 3Adjust time delay (adjustable from 0.1-10 seconds)
  4. 4Adjust low AC voltage threshold setting (adjustable from 50-95% of reference voltage)
  5. 5Adjust time delay (adjustable from 2-20 seconds)
  6. 6Adjust under frequency threshold setting (adjustable from 2-10 Hz below reference governor set point)
  7. 7Adjust time delay (adjustable from 5-20 seconds)
  8. 8Allow downstream protective devices to clear fault conditions using single and three phase fault current regulation
  9. 9Rely on thermal damage curve (3-Phase short) or fixed timer (2 seconds for 1-Phase short, 5 seconds for 2-Phase short) to protect the alternator
  10. 10Adjust over frequency settings (2-10 Hz above nominal governor set point)
  11. 11Adjust time delay settings (1-20 seconds)
  12. 12Shutdown generator set
  13. 13Turn off AVR excitation
  14. 14Warning
  15. 15Instantaneous tripping (if AmpSentry Maintenance Mode is active)
  16. 16Adjust over frequency settings (adjustable from 2 - 10 Hz above nominal governor set point for a 1 - 20 second time delay)

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81 U81O59CODE 4232CODE 4329CODE 4527CODE 4822CODE 57
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