OC2

What does 012 mean?

One of the motor phases has made contact with earth (ground), indicating an earth fault. This suggests an insulation breakdown in the motor cable or the motor windings.

• Insulation breakdown in the motor cable due to mechanical stress (chafing, crushing) or chemical/moisture ingress.
• Internal short circuit or insulation failure within motor windings, often caused by overheating, contamination, or age.
• Improper grounding of the motor frame or drive enclosure, creating an unintended current path to earth.
• Accumulation of conductive dust, metal particles, or moisture on motor terminals or inside the terminal box, bridging phases to ground.

Click steps to track your progress.

1. 1

   1. Disconnect the motor power cables (U, V, W) from the drive's output terminals.

2. 2

   2. Using a megohmmeter (insulation resistance tester), measure insulation resistance between each motor phase (U, V, W) and the motor frame ground terminal. A reading below 1 Megohm (1MΩ) indicates a fault.

3. 3

   3. If motor insulation is good, measure insulation resistance between each conductor of the motor cable and the cable shield/earth conductor.

4. 4

   4. Visually inspect the motor cable along its entire length for signs of damage (cuts, abrasions, crushing) and check the motor terminal box for moisture or debris.

5. 5

   5. If a cable or motor winding fault is confirmed, isolate the faulty component for repair or replacement.