Output Open-Phase

What does LF mean?

An open-phase condition has been detected at the Drive's output, where the output current imbalance exceeds 5% (L8-07=1 enabled). This is commonly caused by a broken wire in the motor cable, a broken winding in the motor, or loose output terminal connections. Operating with an open phase can cause motor damage due to imbalanced currents and vibrations, as well as reduced performance.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Verify that the motor's capacity is not less than 5% of the Drive's maximum motor capacity, as very small motors can sometimes trigger this fault.

2. 4

   If a low impedance motor is used, consider adding output impedance (e.g., a line reactor) to help stabilize current and prevent false open-phase detection.