Overspeed

What does oS mean?

The motor speed feedback exceeded the F1-08 setting, indicating an overspeed condition or excessive overshoot. This can be caused by incorrect speed control parameters, inappropriate speed feedback scaling, or an incorrectly set PG pulse number, leading to unstable or uncontrolled motor speed.

• Motor speed feedback exceeding the value set in Parameter F1-08 (Overspeed Detection Level) due to actual mechanical overspeed.
• Poor tuning of speed control parameters (e.g., C1-01 Proportional Gain, C1-02 Integral Gain) causing instability or excessive overshoot during acceleration/deceleration.
• Faulty or noisy speed feedback signal from the encoder or tachometer, leading to erroneous speed readings detected by the drive.
• Regenerative load condition where the driven machine is forcing the motor beyond the commanded speed (e.g., lowering a heavy load with insufficient braking).
• Parameter F1-08 (Overspeed Detection Level) set too low, triggering a fault under normal operating conditions.

Click steps to track your progress.

1. 1

   Verify the setting of Parameter F1-08 (Overspeed Detection Level) and ensure it is appropriately set above the maximum expected operating speed for the application.

2. 2

   Check the encoder/PG feedback cable for secure connections at both the encoder and drive terminals (e.g., A+, A-, B+, B-) and for proper shielding.

3. 3

   Monitor the actual motor speed feedback value (e.g., U1-07) and the speed reference (e.g., U1-04) using the drive's display or HMI to observe for discrepancies or erratic behavior.

4. 4

   Systematically adjust speed control parameters (e.g., C1-01, C1-02) to improve speed regulation and reduce overshoot, following a structured tuning procedure.

5. 5

   In regenerative applications, confirm the functionality and proper sizing of dynamic braking resistors or regenerative units and check related parameters (e.g., b1-01, b1-02).