ISF fault Emotron VSB Drive indicates Input power supply abnormal. This means there is an issue with the incoming AC power supply, such as severe phase imbalance or a wiring issue.
Possible Causes:
1: Serious voltage imbalance among three phases of power supply.
2: Abnormal bus capacitance.
3: Abnormal input wiring of power supply.
Solutions:
1: Check power grid voltage.
2: Seek services.
3: Check power supply input wiring.