Cause : Power cable phase loss comes when input supply cables are not connected well or single-phase power is applied to three-phase servo drive.

Er.420 fault in inovance IS650 servo drive indicates Power cable phase loss. This means input supply cable is not connected.

1. Check whether RST cables on servo drive side and non-servo drive side are in good condition and connected securely.
2. Confirm power input specification and actual input voltage.
3. Check whether input voltage of each phase.