Classification of vibration sensors
There are 5 types of vibration sensors
The first is the inductive vibration sensor
The electric sensor is based on the principle of electromagnetic induction, that is, when the moving conductor cuts off the magnetic field line in a fixed magnetic field, the electromotive force will be induced at both ends of the conductor. Therefore, the sensor produced by this principle is called an inductive vibration sensor, also known as a magnetoelectric vibration sensor. vibration sensor.
From the point of view of the mechanical receiving principle, the magnetoelectric sensor is a displacement sensor. Since the law of electromagnetic induction is applied to the principle of electromechanical conversion, its electromotive force is proportional to the measured vibration speed, so it is actually a speed sensor. Its output form is usually AC voltage or converted into current output by the circuit. This kind of sensor is generally installed with direction requirements, and the cost is low.
2nd, eddy current vibration sensor
The principle is: the vibration sensor based on the eddy current effect is a non-contact sensor. When the eddy current vibration sensor is working, the vibration parameter of the object is measured according to the displacement through the change of the distance between the sensor end and the measured object. Its precision is high, and the resolution can reach 0.1um (root sensitivity related). It is mainly used for the measurement of vibration displacement. During use, it is necessary to pay attention to the influence of the surrounding electromagnetic field on it. If the electromagnetic field changes strongly, it will have a great impact on the result. influences.
3rd, capacitive vibration sensor
The variable capacitance is obtained by changing the gap or the common area, and then the capacitance is measured to obtain the mechanical vibration parameters. Everyone knows the principle of capacitance. In this way, it is not difficult for us to understand that this kind of capacitive vibration sensor can be divided into variable gap type And variable common area type. The former can be used to measure linear vibration displacement, and the latter can be used to measure angular displacement of torsional vibration. No matter which part of the object is changing, we can measure it. Capacitive vibration sensors have strict requirements on the environment .Generally speaking, they are used in a clean environment, because impurities will affect the change of the capacitance medium.
Fourth, resistance strain vibration sensor
It is a kind of vibration sensor, which represents the mechanical vibration of the measured object through the change of resistance. There are many ways to realize the resistance strain vibration sensor, which can be applied to various sensing elements, among which the resistance strain gauge is more common. It Usually used to measure deformation, but is greatly affected by temperature.
No. 5, piezoelectric vibrationAccelerometer
The sensor uses the piezoelectric effect of the crystal to complete the vibration measurement. When the vibration of the measured object forms a pressure on the piezoelectric vibration sensor, the crystal element will generate a corresponding charge, and the charge number can be converted into a vibration parameter. The initial signal from the sensor is the acceleration The signal can also be converted into velocity or displacement through an integrating circuit. Vibration analysis generally uses acceleration signals. But the low frequency response of this sensor is poor.