Cause : Over voltage in constant speed comes when the inverter's internal main circuit DC voltage to reach or exceed the specified value.

0u3 fault in fuji FRENIC MEGA drive indicates Over voltage in constant speed. This means the motor was commanded to run at a steady, constant speed, the DC bus voltage inside the inverter rose above its safe limit.

1. The protection circuit is activated to stop the inverter output.
2. The circuit may also be activated by a surge voltage produced in the power supply system.
3. Power supply abnormal.
4. Check the input power source.
5. Large load inertia.
6. Add suitable braking devices.