Yaskawa F7 Drive User Manual - Manual (Page 139)

Diagnostics & Troubleshooting 6 - 14
Table 6.2 Alarm Displays and Processing (continued)
Digital
Operator Display
Description Cause Corrective Action
UV2
CTL PS Undervolt
Control Power Supply Undervoltage
Undervoltage of the control circuit when
running.
External load was pulling down
the Drive’s power supplies, or
there was an internal short in the
power/gate Drive board.
Cycle power to the Drive.
Repair or replace the Power PCB/
Gate Drive PCB.
Remove all control wiring and
test Drive.
UV3
MC Answerback
Soft Charge Circuit Fault
The pre-charge contactor opened while the
Drive was running.
Contacts on the soft charge
contactor were dirty and the soft
charge contactor does not
function mechanically.
Cycle power to the Drive.
Check the condition of the soft
charge contactor.
Repair or replace the Power PCB/
Gate Drive PCB.