Cause : Low-voltage at constant speed comes when the DC bus voltage within the drive has fallen below a set limit when the motor is  running at constant speed.

The Lvn fault in delta drive indicates a Low-voltage at constant speed. This means the DC bus voltage within the drive has fallen below a set limit when the motor is stopped or at constant speed.

1. Improve power supply condition.
2. Adjust voltage to the power range of the drive.
3. Check the power system.
4. Increase the capacity of power equipment.
5. Reduce the load.
6. Increase the drive capacity.