Overspeed

What does SOF mean?

An overspeed condition detected. This means the motor speed has exceeded a predefined maximum limit. This can be caused by an overhauling load, incorrect speed reference, or a feedback error. Overspeed can lead to mechanical damage, safety hazards, and motor/drive failure.

• Motor speed exceeding the maximum defined limit (e.g., Parameter P1-10 set too low, actual speed above P1-08).
• Overhauling load causing the motor to be driven faster than the drive's commanded speed (e.g., vertical lift applications).
• Incorrect speed feedback signal from encoder/resolver, providing an erroneous high speed reading (e.g., scaling issue, P1-15).
• Loss of motor control due to drive malfunction, allowing the motor to run freely or to line speed.

Click steps to track your progress.

1. 1

   1. Verify the maximum speed limit parameter (e.g., P1-08 or P1-10) is set correctly and matches the motor's nominal speed.

2. 2

   2. Monitor actual motor speed (e.g., display parameter d0-01) and compare it to the commanded speed reference.

3. 3

   3. Inspect mechanical system for overhauling loads; consider adding braking resistor or regenerative unit if applicable (P2-20).

4. 4

   4. Check speed feedback scaling parameters (e.g., P1-15 for encoder pulses per revolution) for correct values.

5. 5

   5. Disconnect the motor from its load and test the drive in open-loop control (if supported) to isolate mechanical issues.