PF

Input Phase Loss

Yaskawa · VS-616G5 Variable Speed Drive

What does PF mean?

The PF fault occurs when the inverter detects the loss of one or more incoming AC power phases. This is determined by monitoring the DC bus voltage ripple; if the voltage difference (∆V) exceeds a threshold for 0.5 seconds, the fault is declared, and the motor coasts to a stop to prevent damage.

Complete Troubleshooting Guide

  1. 1

    Verify the three-phase input power supply to the inverter using a multimeter; check voltage and current on all phases.

  2. 2

    Inspect all input power wiring, fuses, circuit breakers, and contactors for loose connections, damage, or open circuits.

  3. 3

    Ensure that the input phase loss protection (L8-05) is enabled if this protection is desired. If it's disabled, the inverter will not detect this condition.

  4. 4

    Check for any external power supply issues, such as utility fluctuations or brownouts, that could cause momentary phase loss.