Motor Lost/Disconnected

Was bedeutet Motor Lost ?

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.

• Motor power cables disconnected or broken (e.g., loose terminal connections at VSD or motor, phase loss).
• Open circuit in one or more motor windings (e.g., internal break, burnt winding).
• VSD output contactor (if installed) failed in the open position or its control circuit malfunctioned.
• Incorrectly set motor minimum current threshold parameter (e.g., P1-07 for motor loss detection) causing false trips at low loads.
• Failure of the VSD's internal current sensor or its output power stage (IGBTs).

Klicken Sie auf Schritte, um Ihren Fortschritt zu verfolgen.

1. 1

   Verify motor power cable connections at the VSD output terminals (U, V, W) and at the motor terminal box. Check torque settings.

2. 2

   Perform a continuity test on motor phases (U-V, V-W, W-U) at the motor terminal box. Measure resistance between phases (e.g., 0.1-10 Ohms for a typical motor).

3. 3

   If an output contactor is present, verify its coil voltage and contact continuity when commanded ON by the VSD.

4. 4

   Review VSD parameter P1-07 (Motor Loss Detection Current) and ensure it's set below the motor's expected no-load current but above zero.

5. 5

   Disconnect the motor cables from the VSD. Run the VSD into an inductive load bank (if available) to verify VSD output current sensing.