Cause : OVER FREQUENCY comes when motor is turning faster than highest allowed speed due to incorrectly set minimum/ maximum speed, insufficient braking torque or changes in load when using torque reference.

Trip level is 50 Hz over operating range absolute maximum speed limit (Direct Torque Control mode active) or frequency limit (Scalar Control active). Operating range limits are set by parameters 20.01 and 20.02 (DTC mode active) or 20.07 and 20.08 (Scalar control active)

1. Check minimum/maximum speed settings.
2. Check adequacy of motor braking torque.
3. Check applicability of torque control.
4. Check need for brake chopper and resistor(s).