Overspeed
Schneider Electric · ATV32HD11N4 Variable Speed Drive
¿Qué significa SOF ?
The motor has exceeded its programmed maximum speed or the drive has detected an unstable speed condition, possibly due to a driving load that forces the motor beyond its setpoint. This can lead to mechanical damage or loss of control.
Causas comunes
- Driving load (e.g., conveyor on incline, centrifuge) overhauling the motor, forcing it to rotate faster than the commanded speed.
- Incorrectly set maximum frequency (Parameter P1-09) or maximum speed limit (P1-10) in the drive, causing a trip when motor speed exceeds this value.
- Faulty speed feedback device (e.g., encoder, resolver) providing erroneous high-speed signals to the drive.
- Unstable control loop (e.g., PID regulator, speed controller gains P2-10, P2-11) allowing speed oscillations that momentarily exceed the overspeed threshold.
- Mechanical fault in the driven equipment causing uncontrolled acceleration (e.g., broken gearbox, detached coupling, free-wheeling load).
Pasos de reparación & Lista de verificación
Haga clic en los pasos para seguir su progreso.
- 1
1. Monitor the actual motor speed or frequency (e.g., r0.3, r1.5) via the drive's diagnostic display and compare it to the commanded speed and the maximum frequency setting (P1-09).
- 2
2. If an encoder is used for speed feedback, verify encoder pulse count and direction on a diagnostic display; check wiring of encoder signals (A, /A, B, /B) at drive terminals.
- 3
3. Adjust the maximum frequency parameter (P1-09) and the maximum motor speed parameter (P1-10) to match the application's true operational limits with a safety margin.
- 4
4. If a regenerative load is suspected, lengthen deceleration ramps (P1-12) or install/verify an external braking resistor (Parameter bC1) to absorb excess energy.
- 5
5. Inspect the mechanical connection between the motor and the load for any slippage, broken components, or free-wheeling conditions.
- 6
6. Review and fine-tune the drive's speed control loop gains (e.g., P-gain P2-10, I-gain P2-11) to improve stability and prevent overshoot during transient conditions.