Output Phase Loss

What does LF mean?

An LF fault signifies that one or more of the output phases to the motor has been lost. The drive monitors the RMS current value for each phase and triggers the fault if the current decreases to or below an internal detection level for 10 seconds. This can be caused by a broken motor lead, a loose connection at the motor or drive, or an internal motor winding failure. Operating with an output phase loss can lead to motor overheating, damage to the motor and drive, or severe process disruptions.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Verify that the motor is correctly wired (e.g., star/delta configuration) and that all connections are secure and robust.

2. 4

   Check for any external disconnects or contactors in the motor circuit that might be open or faulty.

3. 5

   Ensure drive parameters related to output phase loss detection and motor protection are correctly configured.