1. Different in nature
1. The nature of the automotive relay: an automatic control device whose output will change in leaps and bounds when the input (electricity, magnetism, sound, light, heat) reaches a certain value.
2. The nature of the fuse: a non-resettable one-time thermal protection device.
Two, the role is different
1. Automobile relay function: mainly used for overload protection. If the fuse is placed correctly in the circuit, when the current rises abnormally to a certain height and generates heat, the fuse will cut off the current by itself, thus protecting the safe operation of the circuit.
2. Fuse function: When the circuit fails or is abnormal, with the current rising, the increased current may damage some important components in the circuit, or burn the circuit, or even cause a fire. If the fuse is correctly placed in the circuit, when the current rises abnormally to a certain height and generates heat, the fuse will cut off the current by itself to protect the safe operation of the circuit.
Automotive relays consist of a magnetic circuit system, a contact system and a recovery mechanism. The magnetic circuit system is composed of magnetic core, yoke, armature, coil and other components. The contact system is composed of static reed, dynamic reed, contact seat and other parts. The recovery mechanism is composed of a recovery reed or an extension spring.
The installation methods of automotive relays include PCB board type, ISO socket installation type, ISO socket installation type, shell fixing, and snap-in installation methods. For relays that are small in size and not frequently replaced, the PCB board type is generally used, and for relays that are frequently replaced, the socket installation method is used.
How to judge whether the car relay is good or bad?
The method of judging the quality of automotive relays is as follows:
1. Use the manual start method of the motor. If the motor can start, it means that there is something wrong with the start relay.
2. For the starting relay of the same model, please connect the circuit according to the figure below, and conduct a power-on test. If the compressor runs normally, it means that there is a problem with the starter. If it should not run, it means that the compressor or the motor is faulty.
3. For the one-arm starting relay, if the starting contact is sucked down after the power is turned on, the armature cannot be picked up automatically within 0.5-3 seconds, and the armature can be screwed up with a screwdriver to see if the motor can run normally. If it works normally, it means that there is something wrong with the starting relay. If the starting contact cannot be sucked in after the power is turned on, use a screwdriver to gently press the armature to see if it can be picked up automatically after being sucked down. If the motor runs normally at this time, it also indicates that there is a problem with the starter relay.
Working principle of automobile main relay
When a certain voltage or current is applied to both ends of the electromagnetic relay coil, the magnetic flux generated by the coil passes through the magnetic circuit composed of the iron core, yoke iron, armature, and magnetic circuit working air gap.
Under the action of the magnetic field, the armature is attracted to the pole surface of the iron core, thereby pushing the normally closed contact of the contact to open, and the normally open contact to close; when the voltage or current at both ends of the coil is less than a certain value, when the mechanical reaction force is greater than the electromagnetic attraction force, The armature returns to the initial state, the normally open contact is disconnected, and the normally closed contact is connected.
English
