Output Ground Fault

What does GF mean?

The Drive has detected an output grounding current exceeding 50% of its rated output current (L8-09 = 1 enabled), indicating a current leakage to ground. This is typically caused by a short in the motor leads, motor windings, or a defective internal current sensor. A persistent ground fault poses a safety risk and can lead to damage to the motor or Drive components.

• Motor cable insulation breakdown due to aging, abrasion, or mechanical damage, causing a phase-to-ground short.
• Water ingress or contamination in the motor terminal box causing a short to the motor frame.
• Internal motor winding insulation failure, resulting in a short to the motor casing.
• Incorrectly terminated motor cables, where a conductor accidentally contacts the conduit or motor frame.
• Damaged Drive output IGBT (Insulated Gate Bipolar Transistor) to heatsink insulation.

Click steps to track your progress.

1. 1

   1. Power down the Drive immediately. Disconnect all three motor leads (U, V, W) from the Drive output terminals.

2. 2

   2. Use a megohmmeter (insulation resistance tester) to test the insulation resistance of each motor phase (U, V, W) to ground. Readings should be above 1 Megohm (1MΩ).

3. 3

   3. Visually inspect the entire length of the motor cable for any signs of damage, cuts, or abrasions on the outer jacket.

4. 4

   4. Open the motor terminal box and inspect for moisture, contamination, or loose/frayed wiring that could be contacting the motor frame.

5. 5

   5. If insulation resistance tests pass for the motor and cable, reconnect the motor and verify parameter L8-09 (Ground Fault Detection) is enabled (set to '1').