Cause : Mech brake opening failed comes when the drive has detected an issue with releasing the mechanical brake on the motor.

The fault code 71A3 in your ABB ACS880 drive indicates a mechanical brake opening failed issue. This means the drive detected a problem with the system responsible for stopping the motor when needed, which is crucial for safety.

1. Check mechanical brake connection.
2. Check mechanical brake settings in parameter group 44 Mechanical brake control.
3. Check that acknowledgement signal matches actual status of brake.