As an Automotive Relay Factory, there is some information to share with you. 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 allows 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 Automotive Relay consists of a magnetic circuit system, a contact system, and a recovery mechanism. The magnetic circuit system consists of iron core, yoke iron, armature, coil and other parts. The contact system consists of static springs, moving springs, contact bases and other components. The restoration mechanism consists of a recovery reed or a tension spring.
(1) Simple method for judging the working performance of relays
Turn on the ignition switch, then use the ear or stethoscope to listen to the presence or absence of the sound in the control relay, or feel the vibration of the relay by hand. If yes, the relay is working normally. The appliance does not work because of other causes. Otherwise, the relay is malfunctioning.
It is also possible to unplug the relay for testing, for example, if the air conditioner compressor does not work, the engine can be started, and then the blower switch and the air conditioner switch can be turned on. Then remove the connector of the air conditioner compressor relay to judge. If the sound of the relay is heard, and the engine speed drops significantly when the relay is unplugged, the engine speed increases when the relay is inserted, indicating that the relay of the air conditioner compressor and its control line are normal.
Regarding the position of the relay, any relays and fuses marked with a dotted line on the schematic diagram are generally arranged in the central power distribution box.
(2) Common barriers to relays
1 The relay coil burned out. In order to prevent this from happening, if the temperature may exceed 80 °C during maintenance, maintenance and electric welding, the temperature-sensitive relay and electronic control unit should be removed.
2 contact ablation. For example, the Jinbei Haishi sedan (using the 491Q-ME engine) relay of the air conditioner condenser fan is just below the glass cleaning spray pipe. If the spray pipe is broken, the cleaning fluid will leak to the relay, making the relay normally open. If the contact is rusted and cannot be disconnected, it will cause the air conditioner condenser fan to keep turning off. Therefore, the relay should be strictly prevented from entering the water.
(3) Try to reduce the contact resistance of the relay contacts
The contact resistance existing between the relay contacts of the vehicle is mainly composed of two parts: a shrinkage resistance and a surface film resistance. The contact resistance of the contacts is related to the contact form of the contacts, material properties and surface processing. It can be seen that to reduce the contact resistance of the relay contacts, it is possible to improve the contact state and improve the contact material when the contact pressure is constant.
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