Cause : Power unit lost comes when connection between the drive control unit and the power unit is lost.

The fault code 5682 in your ABB ACS880 drive indicates a power unit lost - connection between the control unit and the power unit is lost.

1. This means the communication link between the drive's control unit, which manages the operation, and the power unit, which handles power conversion and delivery to the motor, has been disrupted.
2. Check the connection between the control unit and the power unit.