Inverter Output Fault / Earth Fault

What does E.10 mean?

The inverter has detected an output current fault, specifically an earth (ground) fault, on its output side (affecting the motor or connection cable). This indicates a breakdown in insulation, leading to current leakage to ground. An earth fault is a significant safety hazard and can cause severe damage to the motor or inverter if unresolved.

• Deterioration or mechanical damage to motor cable insulation, leading to direct contact with conduit or ground.
• Moisture ingress or contamination within the motor winding, causing a phase-to-ground short circuit.
• Insulation breakdown in the motor terminal box due to loose connections or foreign conductive material.
• Damage to the inverter's output filter (if present) causing leakage current to ground.

Click steps to track your progress.

1. 1

   Power down the inverter and disconnect all motor phases (U, V, W) from the inverter output terminals.

2. 2

   Using a megohmmeter (insulation resistance tester) at 500VDC, measure insulation resistance between each motor phase (U, V, W) and motor frame ground. Verify readings are above 1 MOhm.

3. 3

   Measure insulation resistance of the motor cable between each conductor and the cable shield/ground terminal. Verify readings are above 1 MOhm.

4. 4

   Inspect the motor terminal box for moisture, carbon tracking, or loose connections.

5. 5

   Re-connect only the motor cable to the inverter, leaving the motor disconnected, and run the inverter without a motor (if allowed by model) to isolate the fault to the cable or motor.