Motor Locked Rotor

What does Locked Rotor mean?

This fault occurs when the motor's rotor is prevented from rotating, either mechanically or due to a severe electrical issue, while the drive attempts to supply power. This condition leads to extremely high current draw, which can quickly overheat and damage the motor windings or the VSD's output stage. Immediate intervention is required to prevent component destruction and fire hazards.

• Mechanical jam in the driven equipment (e.g., gearbox seizure, bearing failure, material buildup).
• Overload condition on the motor significantly exceeding its rated torque.
• Incorrect motor parameters set in the drive (e.g., P2-01 (Motor Rated Current) too low).
• Damaged motor bearings or shaft binding internally.
• Brake failure to fully release, causing residual braking torque.

Click steps to track your progress.

1. 1

   Disconnect motor from mechanical load (if possible) and attempt to turn motor shaft manually; it should rotate freely.

2. 2

   Verify motor parameters (e.g., P2-01 (Motor Rated Current), P2-02 (Motor Rated Speed)) are correctly set according to motor nameplate.

3. 3

   Measure motor winding resistance (U-V, V-W, W-U) to check for shorted windings.

4. 4

   Inspect driven machinery for mechanical binding, foreign objects, or bearing failure.

5. 5

   Increase the drive's current limit (e.g., P2-07 (Overload Current Limit)) if the application requires higher starting torque temporarily (with caution).