Cause : DC Bus Undervoltage comes when there is a phase loss in the drive input power. Correct errors with the wiring for main circuit drive input power.

1. Voltage in the DC bus fell below the undervoltage detection level (L2-05).
   • For 200 V class drives: approximately 190 V.
   • For 400 V class drives: approximately 440 when using input voltages 460 V or higher (350 V when E1-01 is less than 400, and 380 V when 400V ≤ E1-01 < 460 V ).
2. The fault is output only if L2-01 is set to 0 or 1 and the DC bus voltage has fallen below the level set to L2-05 for longer than the time set to L2-02.