Overspeed protection switch is suitable for measuring the speed of high-speed shaft and low-speed shaft of wind turbines and providing protection when high-speed shaft and/or low-speed shaft is overspeed. The switch is used to monitor the signals emitted by NPN or PNP proximity switch to achieve its functions.

Has two independent pulse signal processing channels, each channel with its own signal processing flow that does not affect each other. When the input signal frequency exceeds the set value, the switch will output a hardware alarm signal, thus realizing the overspeed protection for the wind turbine generator. The switch adopts two types of signal output: 4-20mA analog and PNP pulse signal, which is convenient for the control system to collect the rotational speed signal.

The signal processing method of the switch adopts algorithms such as pulse width suppression and sliding window mean filtering, which can effectively filter all kinds of interference signals. The alarm determination mechanism has alarm delay and alarm latch functions.