Cause : Electronics thermal relay 1 protection comes when the internal temperature of the drive's electronic components responsible for controlling motor current (likely involving IGBTs) has exceeded a safe operating limit.

The EoL1 error code on your Delta MS300 drive indicates an Electronic thermal relay 1 overload protection has been triggered. This means the drive's internal thermal protection circuit has detected that the electronics (specifically, relay 1) are over heating.

1. Reduce the load.
2. Increase the setting values for Pr.01-12–01-19 (accel./decel. time).
3. Reset to the correct motor rated frequency.
4. Reset to the correct motor rated current.
5. Check the status of the fan, or replace the fan.