Earth fault

What does 14 mean?

A discharge (current leakage) from one or more output phases to ground has been detected. This indicates an insulation breakdown in the motor, the motor cables, or potentially the drive's output stage, posing an electrical safety hazard.

• Degraded motor winding insulation (turn-to-turn or phase-to-ground) due to age, moisture, or overheating.
• Damage to the motor cable shielding or conductor insulation allowing current leakage to ground (e.g., conduit, tray).
• Condensation or conductive dust accumulation inside the motor terminal box creating a short to ground.
• Loose or corroded ground connection for the motor or its cable shielding.
• High frequency leakage currents in shielded cables, especially over long cable runs, if common mode chokes are not used.

Click steps to track your progress.

1. 1

   Disconnect the motor cables from the drive output terminals (U, V, W) and power cycle the drive to determine if the fault is external.

2. 2

   Perform an insulation resistance test on the motor windings to ground (motor frame) using a 500VDC Megger, looking for readings above 1 Megaohm.

3. 3

   Perform an insulation resistance test on the motor cables, checking each phase conductor to the cable shield/ground conductor.

4. 4

   Visually inspect the motor terminal box, motor frame, and cable entry points for signs of moisture ingress or physical damage.

5. 5

   Verify the continuity of the motor's protective earth conductor (PE) from the motor frame back to the main earth busbar in the control cabinet.