28 September 2021
USF fault on ATV61/71.Product Line:
Low voltage on drive's DC bus.Resolution:
USF is a mains undervoltage fault that appears when the drive's DC bus goes below a certain value.
Check the Mains voltage on L1, L2, and L3 with a true RMS meter.
Measure DC voltage on drive's DC bus PA (+) and PC(-) with meter.