Overcurrent Fault

What does 12 mean?

This fault is triggered by the hardware trip circuit detecting an excessive current condition at the controller's output. This is a critical fault that can be caused by a short circuit in the motor windings or wiring, or by severe overload conditions. Ignoring this can lead to immediate damage to the controller's output stage or the motor.

• Phase-to-phase short circuit in the motor wiring (U-V, V-W, or U-W) or within the motor windings.
• Phase-to-ground short circuit in the motor wiring (U, V, or W to ground) or within the motor casing.
• Rapid acceleration of a high-inertia load with acceleration time (P1-03) set too short, causing transient current spikes.
• Motor shaft locked mechanically (e.g., severe jam) while attempting to start or run, leading to immediate high current.
• Internal controller output IGBT failure (e.g., shorted leg) causing uncontrolled current flow.

Click steps to track your progress.

1. 1

   1. Immediately disconnect the motor from the controller's output terminals (U, V, W). Test the controller's output in no-load condition (if supported, or use a dummy load).

2. 2

   2. Measure the insulation resistance of the motor windings to ground (U, V, W to motor frame ground) using a megohmmeter (e.g., 500V DC test voltage). It should be >1 MOhm.

3. 3

   3. Measure the resistance between each motor phase winding (U-V, V-W, W-U) using an ohmmeter. Values should be balanced within 5% and match motor specifications.

4. 4

   4. Inspect the motor cables for any signs of insulation damage, crimping, or contact with conductive surfaces that could cause a short circuit.

5. 5

   5. Increase the acceleration time parameter (e.g., P1-03) to a longer duration to reduce inrush current spikes during motor startup.