Cause : Main circuit overvoltage comes when main circuit input voltage is too high or power supply is instable or affected by the lightning strike.

Er.400 fault in inovance IS650 servo drive indicates Main circuit overvoltage . This means the main circuit voltage has exceeded the permissible limit.

1. Check whether power supply is instable, affected by lightning strike or satisfies preceding specification.
2. Check power input specification of servo drive.
3. Measure RST input voltage on servo drive side and check whether input voltage complies with the following specification.