Soft Charge Circuit Fault

What does UV3 mean?

The pre-charge contactor, responsible for managing the initial charging of the DC bus capacitors, opened unexpectedly while the drive was running. This often indicates a mechanical issue with the contactor itself, such as dirty or worn contacts, preventing proper mechanical operation or causing premature opening.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   If the contactor is physically damaged or fails to operate correctly, repair or replace the contactor or the associated Power PCB/Gate Drive PCB, which may contain the contactor control circuit.