Output Phase Loss

What does LF mean?

The drive has detected a loss of one or more phases at its output terminals, typically indicating a motor cable break, poor connection, or motor winding issue. This prevents proper motor operation.

Click steps to track your progress.

1. 1

   Inspect motor power cables and terminal connections for physical damage, insulation breakdown, and ensure all connections at both the drive output (U, V, W) and motor terminal box are tight and free from corrosion.

2. 2

   Measure the resistance between each motor phase (U-V, V-W, W-U) and from each phase to ground after disconnecting the motor from the drive. Compare readings for balance and ensure no phase-to-ground faults.

3. 3

   Verify the drive's output parameter settings (motor nominal voltage, current, frequency) against the connected motor's nameplate data to ensure correct configuration.

4. 4

   Measure the continuity of each individual phase conductor of the motor cable from end to end after disconnecting the cable from both the drive and the motor, to confirm no internal breaks.