Cause : Power Supply Undervoltage comes when the input power supply voltage became equal to or lower than the Input Power Supply Undervoltage Detection Level (L2-21).

200 V Class: Approximately 150 Vrms
400 V Class: Approximately 300 Vrms

1. The power supply voltage is low.
2. Increase the power supply voltage.
3. A phase loss occurred in the input power supply.
4. Check the input power supply for phase loss or an imbalance in the interphase voltages.
5. Investigate and correct the cause and then reset the fault.