Output Phase Loss

What does LF mean?

This fault occurs when one of the inverter's output phases to the motor is lost, typically detected if the RMS current value for a phase drops below a detection level for 10 seconds. This indicates a potential disconnection, break in motor wiring, or a fuse blown on one phase. Operating with phase loss can lead to motor overheating, vibration, and uneven wear, severely damaging the motor.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Measure the resistance of each motor winding to ensure they are balanced and continuous.

2. 4

   Verify that the output phase loss protection (L8-07) is enabled and set appropriately for the application.

3. 5

   If contactors are present between the inverter and motor, check their contacts for pitting or failure.