Earth fault II

What does ALARM 44 mean?

There is an electrical discharge from one of the output phases to ground, either in the cable between the frequency converter and the motor or within the motor itself. This poses a significant safety risk and can cause severe equipment damage.

• Severe insulation breakdown in the motor cables, creating a direct path from a phase conductor to ground.
• Catastrophic motor winding insulation failure, causing a phase-to-ground short circuit within the motor.
• Significant moisture ingress or conductive debris accumulating in the motor terminal box or drive output terminals.
• Incorrect or damaged installation of the drive output filter (if used), leading to ground current leakage.
• Damage to the internal power components (e.g., output IGBTs) leading to a permanent ground fault.

Click steps to track your progress.

1. 1

   Power off the drive and disconnect motor cables from drive terminals (U, V, W). Perform an insulation resistance test (megger) from each motor cable conductor to ground (PE).

2. 2

   Perform an insulation resistance test (megger) from each motor winding terminal (U, V, W) to the motor frame (PE).

3. 3

   Visually inspect the motor terminal box and drive output terminal area for severe contamination, carbon tracking, or rodent damage.

4. 4

   Verify the integrity of the protective earth (PE) connection from the motor frame to the drive's PE terminal and the main power distribution system.

5. 5

   If all external components (motor, cables) pass insulation tests, the fault may indicate an internal drive component failure; contact service.