Cummins

81 U

UnclassifiedElectrical

What This Code Means

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); Generator set is operating at a potentially damaging frequency level; 3-Phase short circuit (thermal damage); Shutdown of generator set; Voltage on any phase has dropped below a preset value

Possible Causes

  • •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
  • •High AC voltage
  • •Low AC voltage
  • •Under frequency
  • •Over frequency
  • •Short circuit
  • •Output frequency drops 2-10 Hz below nominal governor set point for a 5-20 second time delay
  • •Generator set frequency rises 2-10 Hz above nominal governor set point for a 1-20 second time delay
  • •Loss of voltage sensing inputs to the control
  • •Field overload condition
  • •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

Suggested Actions

  1. 1Adjust high AC voltage threshold setting (adjustable from 105-125% of nominal voltage)
  2. 2Adjust time delay (adjustable from 0.1-10 seconds)
  3. 3Adjust low AC voltage threshold setting (adjustable from 50-95% of reference voltage)
  4. 4Adjust time delay (adjustable from 2-20 seconds)
  5. 5Adjust under frequency threshold setting (adjustable from 2-10 Hz below reference governor set point)
  6. 6Adjust time delay (adjustable from 5-20 seconds)
  7. 7Allow downstream protective devices to clear fault conditions using single and three phase fault current regulation
  8. 8Rely 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
  9. 9Shutdown generator set
  10. 10Turn off AVR excitation
  11. 11Warning
  12. 12Instantaneous tripping (if AmpSentry Maintenance Mode is active)

Related Cummins Fault Codes

81OCODE 4281 OCODE 4359CODE 4532CODE 4829CODE 5727EMERGENCY STOP
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