The rotational speed sensor CS-3 is a commonly used speed sensor for steam turbines. It is significantly different from our common CS-1 speed sensor, as it is an active speed sensor. Active refers to the sensor having a built-in electronic signal generator or driver. This type of sensor generates a magnetic field through an excitation circuit and measures the speed of the target object. It uses the magnetoresistive effect to detect changes in the magnetic field on rotating components and convert them into electrical signals for output.

The active electronic signal generator or driver in sensors is usually powered by a separate power source and can actively generate or drive electrical signals. This active signal generator can provide stronger signal output, enabling sensors to have better sensitivity and performance. Therefore, active speed sensors have higher accuracy and reliability in detecting low speed or weak magnetic field changes.
Due to this feature, the active speed sensor CS-3 can be used to measure the speed of the boiler feedwater pump, as the feedwater pump often has zero speed and reverse rotation situations. Moreover, due to the presence of internal electronic circuits, active sensors CS-3 can provide more stable and consistent signal output, reducing the impact of external interference on sensor performance, and making it easier to install and use.

Meanwhile, the sensor CS-3 adopts a stainless steel threaded structure, which has strong anti-interference ability and can also detect impact devices. The stainless steel protective sleeve can isolate it from harmful media and extend its service life.