Uv3
UV3 means Soft Charge Circuit Fault.
It will only apply too larger drives. On an F7 drive 240VAC type, the fault only applies to drives larger than 30kw. For a 480VAC type, the fault will only apply to a drive larger than 55kw.
All drives have a charging resistor to limit current through the DC Bus Capacitors when power is first applied. After the capacitors reach a certain charging level, a relay energizes and closes contacts to short around the charging resistor.
Larger drives have an auxilary contact called the answerback contact which supplies a signal to the control board regarding the state of the relay. The auxilary contact has opened while the drive is running. The inverter thinks the charging resistor is no longer shorted out and current is flowing through this resistor. It will now get hot and could catch on fire.
UV3 means SOFT CHARGE CIRCUIT FAULT
The pre-charge contactor opened while the Drive was running.
Common Causes include:
Contacts on the soft charge contactor were dirty and the soft charge contactor does not function mechanically
Corrective action includes:
Cycle power to the drive. You should be able to hear the contacts on the relay click as the bus capacitors are charging up.
Check the condition of the soft charge contactor. You can measure the resistance across the contacts. Large drives have relays that are replaceable.
If the contacts are making good contact, check the ribbon cable to the gate drive board. Replace the power/gate drive board.
CSH 01-14-09
