Cause : DC Bus Undervoltage comes when the voltage level on the DC bus of the drive has fallen below the acceptable threshold.

1. One of the following conditions occurred while the drive was running:

• The DC bus voltage is ≤ L2-05 208-240Vac: Trip point is ≤ 190Vdc 480Vac: Trip point is ≤ 380Vdc

2. Input power phase loss

• The main circuit drive input power is wired incorrectly.
• Correct the wiring.

3. One of the drive input power wiring terminals is loose

• Ensure there are no loose terminals.
• Apply the tightening torque specified in this manual to fasten the terminals

4. There is a problem with the voltage from the drive input power

• Check the voltage.
• Correct the voltage to be within the range listed in drive input power specifications.
• If there is no problem with the power supply to the main circuit, check for problems with the main circuit magnetic contactor.