Overcurrent During Constant Speed

What does E.OC2 mean?

This fault occurs when the inverter's output current reaches or exceeds approximately 230% of the rated current while operating at a constant speed. This activates the protection circuit, causing the inverter output to shut down. Common causes include sudden load changes, output short-circuits, or incorrect control parameters. Repeated overcurrent can lead to motor and inverter damage.

• Excessive continuous mechanical load on the motor, exceeding its rated current capacity.
• Motor winding short circuit (phase-to-phase or phase-to-ground) occurring during operation.
• Incorrect motor parameters (e.g., P0-03 motor rated current, P0-06 motor rated frequency) causing miscalculation of load.
• Intermittent short circuit in motor cables due to insulation damage or vibration.

Click steps to track your progress.

1. 1

   Measure actual motor load current with a clamp meter during constant speed operation and compare to motor nameplate and P0-03.

2. 2

   Inspect driven machinery for mechanical binding, bearing failure, or excessive friction using a torque wrench or by manual rotation.

3. 3

   Perform a motor winding resistance test (phase-to-phase) and insulation resistance test (winding-to-ground) using a multimeter and megohmmeter respectively.

4. 4

   Verify motor control parameters (e.g., P0-03, P0-06) against the motor nameplate data for accuracy.

5. 5

   Check for loose connections or signs of arcing at inverter output terminals (U, V, W) and motor terminal box.