EARTH FAULT / INT. CUR UNBAL xx

What does 2330 mean?

The ABB ACS800 drive has detected an unbalance in the load current, typically indicating an earth fault in the motor or its power cables, or excessive output current unbalance in a specific inverter module (xx refers to module number 1-12) of parallel-connected inverter units. This fault (3.08 AW 1 bit 14, 3.05 FW 1 bit 4, 4.01) protects against insulation breakdown and potential equipment damage or safety hazards, and is controlled by programmable Fault Function 30.17.

• Earth fault in the motor windings or internal motor components.
• Earth fault in the motor power cables connecting the drive to the motor.
• Presence of power factor correction capacitors or surge absorbers incorrectly installed in the motor cable between the drive and the motor.
• Internal fault within a specific inverter module (xx), such as a damaged IGBT or gate drive circuit, leading to current unbalance.

Click steps to track your progress.

1. 1

   Disconnect the motor from the ABB ACS800 drive. Measure insulation resistance between each motor phase (U, V, W) and motor frame (ground) using a megger at appropriate voltage (e.g., 500VDC or 1000VDC); expect values >1 MΩ.

2. 2

   Disconnect the motor cables from both the drive and the motor. Measure insulation resistance between each cable phase and ground, and between phases, using a megger; expect values >1 MΩ.

3. 3

   Verify that no power factor correction capacitors or surge absorbers are connected in the motor cable circuit between the drive and the motor.

4. 4

   Inspect the motor and cable for any visible signs of damage, wear, moisture ingress, or poor terminal connections.

5. 5

   If the fault persists and no external earth fault is detected, note the inverter module number (xx) from the fault message and contact your local ABB representative for further diagnosis of the specific inverter module.