Motor Lost/Disconnected

What does Motor Lost mean?

This fault indicates that the variable speed drive has detected that the motor is no longer connected or that its output current has dropped below a critical threshold while the drive is commanded to run. This can be caused by a broken motor cable, a disconnected motor, or a severe motor internal fault (e.g., open winding). Operating without a motor or with a disconnected motor can lead to unstable control and potential damage to the VSD output stage, though typically less severe than a short circuit.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Verify the motor windings for open circuits using a multimeter to check phase-to-phase continuity.

2. 4

   Ensure the motor is properly connected and not mechanically uncoupled from the driven equipment.