Overspeed

What does OS mean?

An Overspeed (OS) fault occurs when the motor speed feedback, typically from the PG, exceeds the configured overspeed detection level (F1-08) for a duration longer than the delay time (F1-09). This indicates the motor is running faster than its allowed maximum, potentially due to incorrect control parameters, regenerative load conditions, or an encoder issue. Unresolved overspeed can lead to mechanical damage to the motor or driven equipment, and create safety hazards.

• Excessive load inertia or overhauling load causing the motor to accelerate beyond the commanded speed and exceed the F1-08 threshold.
• Incorrect setting of parameter F1-08 (Overspeed Detection Level) or F1-09 (Overspeed Detection Delay Time), making the detection too sensitive.
• Faulty or noisy speed feedback signal from the encoder (PG), leading to erratic speed readings that momentarily exceed the overspeed limit.
• Malfunction in the drive's speed control loop, causing it to lose control and allow the motor to accelerate freely.
• Incorrect scaling of the encoder feedback (e.g., F1-02 Pulses per Revolution) or motor parameters, resulting in an inaccurate representation of actual motor speed.

Click steps to track your progress.

1. 1

   Monitor the motor's actual speed (e.g., 'PG Feedback Speed' monitor) on the drive's operator panel and compare it against the commanded speed and the F1-08 (Overspeed Detection Level) setting.

2. 2

   Adjust parameter F1-08 (Overspeed Detection Level) to a value slightly above the maximum expected operating speed, ensuring it provides adequate margin for normal operation.

3. 3

   Adjust parameter F1-09 (Overspeed Detection Delay Time) to account for momentary speed fluctuations during acceleration or load changes.

4. 4

   Inspect the encoder and its cabling for proper mounting, secure connections, and shielding integrity to prevent signal noise.

5. 5

   Perform a drive auto-tune (if not recently done) and verify motor parameters (E1-01, E1-02, F1-02) are correctly configured to ensure accurate speed control.