4P-5820 Automobile Speed Sensor

The Speed Sensor is a sensor that converts the rotational speed of a rotating object into an electrical output. The speed sensor is an indirect measuring device, which can be manufactured by mechanical, electrical, magnetic, optical and hybrid methods. According to different signal forms, speed sensors can be divided into analog and digital.

Working principle: Most of them output pulse signal (approximate sine wave or rectangular wave). The methods for measuring speed with pulse signal include frequency integration method (i.e. F/V conversion method, whose direct result is voltage or current) and frequency operation method (whose direct result is digital).
In automation technology, there are many measurements of rotational motion speed, and the linear motion speed is often measured indirectly through the rotational speed. The DC tachogenerator can convert the rotating speed into electrical signals. The tachometer requires a linear relationship between the output voltage and the speed, a large output voltage gradient, and good time and temperature stability.
The tachometer can generally be divided into DC type and AC type. The rotary speed sensor is in direct contact with moving objects. When the moving object contacts the rotary speed sensor, the friction force drives the roller of the sensor to rotate. The rotation pulse sensor installed on the roller sends out a series of pulses. Each pulse represents a certain distance value, so that the linear velocity can be measured. The electromagnetic induction type is used to install a gear on the rotating shaft, with an electromagnetic coil on the outside. The rotation is due to the passage of the gear tooth clearance, so that the square wave voltage can be obtained, and then the speed can be calculated.
The rotary speed sensor has no direct contact with moving objects. The blade edge of the impeller is pasted with a reflective film, which drives the impeller to rotate when the fluid flows. The optical fiber transmits reflective light once every rotation of the impeller, generating an electric pulse signal. The speed can be calculated from the number of pulses detected.