5081 Auxiliary Fan Broken fault in ABB ACS880 Drive

5081 Auxiliary Fan Broken in the ABB ACS880 Drive indicates that an auxiliary cooling fan connected to the fan connectors on the control unit is either stuck, disconnected, or not operating correctly. The ACS880 continuously monitors the status of auxiliary cooling fans through their feedback signals. If a fan stops rotating or its feedback is lost, the drive generates Fault 5081 to protect the drive and associated equipment from insufficient cooling.

The auxiliary fault code identifies which fan has failed:

  • Auxiliary Code 1 – Auxiliary Fan 1
  • Auxiliary Code 2 – Auxiliary Fan 2

Possible Causes

  • Auxiliary cooling fan failure.
  • Auxiliary fan seized or mechanically stuck.
  • Auxiliary fan disconnected from the control unit.
  • Loose or damaged fan connector.
  • Broken or damaged fan wiring.
  • Dust or debris preventing fan rotation.
  • Auxiliary fan power supply failure.
  • Faulty fan feedback signal.
  • Defective auxiliary fan control circuit.
  • Front cover of the drive module not installed correctly.
  • Front cover not tightened properly.
  • Parameter 31.36 Aux Fan Fault Bypass not enabled during commissioning when operating with the front cover removed.
  • Internal control unit hardware fault.
  • Aging or worn auxiliary cooling fan.

Solutions

  • Check the identified auxiliary cooling fan for proper operation.
  • Verify that the fan rotates freely without obstruction.
  • Inspect the fan for dust or debris and clean it if necessary.
  • Check all fan connectors and ensure they are securely connected.
  • Inspect fan wiring for loose, broken, or damaged connections.
  • Verify the auxiliary fan power supply voltage.
  • Replace the faulty auxiliary cooling fan if it is not operating correctly.
  • Check the fan feedback signal to the control unit.
  • Ensure the front cover of the drive module is correctly installed and tightened.
  • During commissioning, if the front cover must remain removed, activate Parameter 31.36 – Aux Fan Fault Bypass within 2 minutes after the control unit reboots to temporarily suppress the fault.
  • Inspect the control unit if the fan and wiring are normal.
  • Replace the control board if an internal hardware fault is confirmed.

Additional Information

The ABB ACS880 can use one or more auxiliary cooling fans connected directly to the control unit to improve cooling of the drive module or cabinet.

The drive continuously monitors these fans for proper operation. If a fan becomes disconnected, stops rotating, or fails to provide a feedback signal, the drive trips with:

5081 – Auxiliary Fan Broken

This protection prevents overheating caused by inadequate cooling and helps protect the drive's power electronics.

The auxiliary fault code indicates which fan requires inspection:

  • 1 = Auxiliary Fan 1
  • 2 = Auxiliary Fan 2

During drive commissioning, removing the front cover may temporarily interrupt airflow and auxiliary fan monitoring. ABB recommends enabling:

Parameter 31.36 – Aux Fan Fault Bypass

within 2 minutes after the control unit restarts if the front cover must remain off during commissioning.

Once commissioning is complete, reinstall and tighten the front cover and disable the bypass so that normal fan monitoring resumes.

Common Symptoms

  • Drive trips with Fault 5081.
  • Auxiliary cooling fan is not rotating.
  • One auxiliary fan operates while another remains stopped.
  • Reduced airflow inside the drive cabinet.
  • Abnormal fan noise before failure.
  • Drive enclosure temperature gradually increases.
  • Fault occurs immediately after power-up if the fan is disconnected.
  • Fault appears after removing the drive front cover during commissioning.
  • Fault reappears after reset until the defective fan is repaired.

Recommended Troubleshooting Sequence

  1. Identify the faulty fan using the auxiliary fault code.
  2. Verify that the auxiliary fan is rotating.
  3. Inspect the fan blades for blockage.
  4. Clean dust and debris from the fan.
  5. Check fan connectors for secure connection.
  6. Inspect fan wiring for damage.
  7. Measure the auxiliary fan supply voltage.
  8. Verify the fan feedback signal.
  9. Replace the faulty auxiliary fan if required.
  10. Ensure the drive front cover is properly installed and tightened.
  11. During commissioning, activate Parameter 31.36 – Aux Fan Fault Bypass if operating with the front cover removed.
  12. Inspect the control unit if the fault persists.
  13. Replace the control board if necessary.

Auxiliary Fan Check Table

Check PointAction
Auxiliary fanVerify proper operation
Auxiliary fault codeIdentify Fan 1 or Fan 2
Fan rotationEnsure fan rotates freely
Fan bladesRemove dust and obstructions
Fan connectorCheck secure connection
Fan wiringInspect for damage
Fan supply voltageVerify correct voltage
Fan feedbackConfirm feedback signal is present
Front coverEnsure properly installed and tightened
Parameter 31.36Enable Aux Fan Fault Bypass during commissioning if required
Control unitInspect if the fault persists
Control boardReplace if internal hardware failure is confirmed

Preventive Maintenance Tips

  • Inspect auxiliary cooling fans during scheduled maintenance.
  • Clean fan blades and ventilation passages regularly.
  • Replace aging or noisy auxiliary fans before failure.
  • Check fan connectors and wiring for secure connections.
  • Keep the drive front cover properly installed during normal operation.
  • Maintain a clean cabinet environment to prevent dust buildup.
  • Periodically verify auxiliary fan operation using drive diagnostics.
  • Ensure adequate airflow around the drive and inside the cabinet.
  • Use Parameter 31.36 – Aux Fan Fault Bypass only during commissioning when the front cover must be removed.
  • Replace auxiliary fans according to ABB's recommended maintenance schedule.

Proper inspection of auxiliary cooling fans, secure electrical connections, regular cleaning, correct installation of the drive front cover, and timely replacement of faulty fans will help prevent recurring 5081 Auxiliary Fan Broken faults in ABB ACS880 drives, ensuring reliable cooling and long-term protection of the drive's power electronics.

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