The role of the car relay, the role of the relay, the r […]
The role of the car relay, the role of the relay, the relay function is to use the switch to control the relay coil, then the relay working contact is closed or open, the contact is connected to the main line current, and the other end is connected to the electrical appliance to be controlled to achieve small The current controls the large current to prevent the switch from being a large current that causes the switch to burn out. Protects lines and switches.
A relay is an automatic control device that changes the output when the input quantity (electricity, magnetism, sound, light, heat) reaches a certain value. The car relay is a relay used in the car. This type of relay has high load switching power and high impact and vibration resistance. The power supply in the car is mostly 12V, and the coil voltage is designed to be 12V. Because the battery is powered, the voltage is unstable; the environmental conditions are bad, the suction voltage V≤60%VH (fixed working voltage); the coil overvoltage is allowed to reach 1.5VH. The coil consumes a large amount of power, generally 1.6 to 2 W, and the temperature rise is high. Environmental requirements are quite demanding: in the engine compartment, the ambient temperature range is -40 ° C ~ 125 ° C, other locations ambient temperature range is -40 ° C ~ 85 ° C; relays used in the engine compartment to withstand sand, water, salt Oil damage; vibration and impact are quite harsh.
The role of automotive relays
The simplest car relay is to change the control circuit. It is equivalent to one switch, and the other is to increase the current. In fact, the function of the car relay is consistent with the function of the general relay, mainly playing the role of "switch".
1 protection control switch
The control switch only controls the on and off of the relay coil, and the electromagnetic force generated by the relay coil turns on and off the circuit to be controlled by the control switch. After the relay is added, the control switch only flows through the smaller relay coil current, so the switch is not easily damaged and the service life is prolonged.
2 achieve automatic control
Some miniature relay coil currents are controlled by a certain operating voltage in the automotive circuit. When the controlled voltage in the circuit reaches the set relay operating voltage, the relay contacts change the working state, thereby achieving automatic control. For example, the starter drive protection relay can generate electricity after the engine is started, and the relay contact is opened by the midpoint voltage of the generator, and the circuit of the electromagnetic switch of the starter is automatically disconnected.
For the role of automotive relays, we can sum up the point that automotive relays can control large currents with very small currents. Automotive relays are often used to control headlights, horns, air conditioners, ignition, etc。