Overcurrent

What does OCF mean?

This fault indicates that the current drawn by the motor has exceeded the drive's maximum permissible limit. Common causes include incorrect drive or motor parameters, excessive mechanical load, or a mechanical locking of the driven equipment. An overcurrent condition can quickly damage both the motor windings and the drive's output power stage (IGBTs).

• Excessive mechanical load on the motor (e.g., jammed conveyor, seized bearing, binding mechanism).
• Incorrect motor nameplate parameters entered in the drive (e.g., P0-02 Rated Voltage, P0-03 Rated Current).
• Short circuit in the motor windings (e.g., phase-to-phase, phase-to-ground) or motor cable.
• Drive output phase imbalance due to internal IGBT failure or damaged output filter components.
• Too short acceleration ramp time (e.g., Parameter P1-03) for the connected load and motor inertia.
• Faulty internal current sensor within the drive providing an inaccurate measurement.

Click steps to track your progress.

1. 1

   1. Disconnect the motor from the load and check if the motor shaft can rotate freely by hand.

2. 2

   2. Verify all motor nameplate data (e.g., P0-02, P0-03, P0-04, P0-05) are accurately entered in the drive parameters.

3. 3

   3. Perform a motor insulation resistance test (Megger test) on motor windings and motor cable for shorts.

4. 4

   4. Increase the acceleration ramp time (e.g., Parameter P1-03) to reduce the initial current surge.

5. 5

   5. Measure output currents on all three phases (U, V, W) using a clamp meter during startup to check for imbalance.

6. 6

   6. Temporarily reduce the maximum current limit (e.g., Parameter P1-54) to see if the fault can be avoided (for testing only).