Cause : Input Power Supply Fault comes when the fluctuation in the voltage of the input power supply is too large. The voltage balance in the three-phase power supply has broken down. (Detected when L8-69 = 1.)

1. A phase loss occurred in the input power supply
2. The capacity of the power supply is too small.
3. The wiring is too long.
4. The phase imbalance is too large.