Input Phase Failure

What does -PHF mean?

This fault indicates a loss or significant imbalance of one or more input phases to the drive controller. Common causes include blown line fuses, loose connections, or an issue with the utility supply. Using a 3-phase drive on a single-phase supply without proper configuration can also trigger this. Operating with missing phases can lead to motor and drive damage due to unbalanced currents.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Confirm that all input power connections are tight and secure at the drive terminals, main disconnect, and upstream distribution panel. Ensure the drive is supplied with proper 3-phase power if required by its model.