Drive: Motor overspeed

What does F07901 mean?

The motor's actual speed has exceeded its configured maximum permissible limit, either in the positive or negative direction. This indicates a potential loss of speed control, incorrect parameterization, or an external force driving the motor. Exceeding the motor's rated speed can lead to mechanical failure, rotor damage, or safety hazards.

• Incorrect maximum speed setting in drive parameters (e.g., P1-08 maximum motor speed) that is lower than the application's actual speed demand.
• Loss of motor speed control due to faulty encoder feedback (e.g., broken wires, loose connection, noisy signals) if operating in closed-loop vector control.
• Instability in the speed control loop (e.g., P gain too high, I gain too low in P2-10, P2-11) causing overshoot and oscillations.
• Mechanical uncoupling or gearbox failure, leading to the motor spinning freely at a higher speed than expected for the load.
• Faulty internal speed sensor (e.g., resolver, hall effect) or its associated wiring within the motor or drive.

Click steps to track your progress.

1. 1

   Verify drive parameter P1-08 (Maximum motor speed) against the application's required maximum speed and the motor's physical limits.

2. 2

   Check the actual motor speed using an external tachometer (e.g., laser tachometer) and compare it to the speed displayed in the drive's monitoring parameters (e.g., P2-05).

3. 3

   If closed-loop control is used, inspect the encoder feedback cable for damage, loose connections, or proper shielding at the drive's encoder input (e.g., X3 terminals).

4. 4

   Review speed control loop parameters (e.g., P2-10 speed controller P gain, P2-11 speed controller I gain) for appropriate tuning relative to the load inertia.

5. 5

   Check for mechanical integrity between the motor and the driven load (e.g., coupling, gearbox) to ensure no slippage or uncoupling has occurred.