Cause : Loss of synchronism detection comes when the inverter trips when the motor operation is not synchronized. (This function is only available under PM sensorless vector control.)

1. Check that the PM motor is not driven overloaded.
2. Check if a start command is given to the inverter while the PM motor is coasting.
3. Check if a motor is connected under PM sensorless vector control.
4. Set the acceleration time longer.
5. Reduce the load.
6. Check the connection of the IPM motor.