Motor Overcurrent

What does Over curr F mean?

This fault indicates that the current drawn by the motor has exceeded its rated limit, typically during acceleration, steady-state operation, or sudden load changes. Causes can include excessive mechanical load, a short circuit in the motor or cable, or incorrect motor parameters. High currents generate excessive heat, which can quickly damage motor windings, cables, and the VSD's output stage.

• Excessive mechanical load on the motor (e.g., jammed machinery, worn bearings, misaligned coupling, product blockage).
• Short circuit or phase-to-ground fault within the motor windings or the motor power cables (U, V, W).
• Incorrect motor parameters (e.g., P1-04 motor rated current, P1-06 motor rated voltage) entered into the VSD.
• Acceleration ramp time (e.g., P1-02) set too short, causing high inrush current during start-up.
• Failure of VSD output IGBTs or the internal current measurement circuit.

Click steps to track your progress.

1. 1

   Measure the mechanical torque required to turn the driven equipment manually or with a dynamometer. Compare to motor rated torque.

2. 2

   Perform an insulation resistance test (Megger test) on motor windings to ground and phase-to-phase. Expected value >1 MOhm.

3. 3

   Verify VSD parameters P1-04 (motor rated current), P1-05 (motor rated speed), P1-06 (motor rated voltage) match the motor nameplate exactly.

4. 4

   Increase the acceleration ramp time parameter (e.g., P1-02) by 20% and retest. Monitor actual motor current (AOUT) on the VSD display.

5. 5

   Disconnect the motor, run the VSD in 'no motor' mode (if supported). If the fault persists, use an oscilloscope to check VSD output phases U, V, W for balanced voltage.