Some knowledge about auto relay you might not know

Automotive relays play the role of switches in the electrical automation industry, which is the intermediate link that controls the on and off of the next circuit by controlling the on and off of one circuit. Therefore, the role of the automotive relay is to control the size and on-off of the current.


A relay is an automatic control device whose output will change leaps and bounds when the input (electricity, magnetism, sound, light, and heat) reaches a certain value. Automotive relays are relays used in automobiles. This type of relay has high switching load power, high shock resistance and vibration resistance.


When a certain voltage or current is applied to the two ends of the electromagnetic relay coil, the magnetic flux generated by the coil passes through the magnetic circuit composed of the core, yoke, armature, and the working air gap of the magnetic circuit. Under the action of the magnetic field, the armature is attracted to the pole surface of the core. Thus, the normally closed contact of the contact is pushed to open, and the normally open contact is closed; when the voltage or current at both ends of the coil is less than a certain value, and the mechanical reaction force is greater than the electromagnetic attraction, the armature returns to the initial state, and the normally open contact is disconnected. The normally closed contact is turned on.


Then, the automobile relay can be regarded as an assembly composed of two parts: the control circuit of the coil and the main circuit of the contact. In the control circuit of the relay, there is only a small working current. This is because the contact capacity of the control switch is small, and it cannot be used to directly control the load with large electricity consumption. It can only be controlled by the contact of the relay On and off.


The relay is not only a control switch, but also a control object (actuator). Take the fuel pump relay as an example, it is the control switch of the fuel pump, but the coil of the fuel pump relay can only form a loop through the grounding point of the electronic control unit when the driving transistor in the electronic control unit is turned on.

Post time: Sep-27-2021