Cause : DC Bus Undervolt comes when the main circuit DC voltage is below the Undervoltage Detection Level (L2-05).

200-240 V Class: Approx. 190 V
380-480 V Class: Approx. 380 V

Main Circuit Magnetic Connector Operation Failure The magnetic connector stopped responding during Inverter opera- tion. Applicable Inverter Capacities 200-240 V Class: 30 to 110 kW 380-480 V Class: 55 to 300 kW.

1. An open-phase occurred with the input power supply.
2. A momentary power loss occurred.
3. The wiring terminals for the input power supply are loose. 
4. The voltage fluctuations in the input power supply are too large.
5. Fault occurred in the surge prevention circuit.
6. The magnetic contactor in the control circuit was released (Contact failure in the auxiliary contact).
7. The contact of the magnetic contactor in the control circuit was corroded due to environmental dust or gas.
8. A fuse on the Change Power Tap Circuit Board has blown for a 400 V Class Inverter of 55 kW or higher.
9. Reset the fault after correcting its cause.
10. Improve the power supply environment. (Check to see if the correct power tap is selected.) 
11. Improve the operating environment.
12. Replace the Inverter.