Cause : Power Supply Undervoltage Pre-Alarm comes when the input power supply voltage became equal to or lower than the Input Power Supply Undervoltage Detection Level.

1. 200 V Class: Approximately 150 Vac
2. 400 V Class: Approximately 300 Vac
3. The converter enters the baseblock state during pre-alarm.
4. When the input supply voltage is restored during the pre-alarm, the converter will release the base block and continue to operate.
5. The power supply voltage is low. Increase the power supply voltage.
6. A phase loss occurred in the input power supply.
7. Check the input power supply for phase loss or an imbalance in the interphase voltages.
8. Investigate and correct the cause and reset the fault.