Speaking of relays, I believe that students who study electrical appliances are no strangers. It doesn't matter if you don't learn electrical appliances, because now everyone has relays in their homes. From the button switch on the wall to the main switch of the power supply, they are everywhere in our lives. The relay manufacturer tells you that the relay is actually an "automatic switch" that uses a small current to control a large current, and it plays the role of automatic adjustment, safety protection, conversion circuit, etc. in the circuit.
Working principle of relay
When the switch that controls the electromagnetic coil is closed, the electromagnetic coil generates a magnetic field, and the electromagnetic field generates magnetism to generate attraction to the armature and the relative position of the armature changes. This change is transmitted to the transmission device, pushing the movable reed contact to communicate with the static reed contact. is turned on by the control circuit.
When the switch that controls the electromagnetic coil is turned off, the magnetic field of the electromagnetic coil disappears, and the armature returns to its initial state under the action of additional devices (such as springs and shrapnel), the reed contacts are separated, and the control circuit is disconnected.
Working principle of solid state relay
Close the switch K that controls the power supply, the coil is energized, and the coil generates magnetic lines of force in the iron core according to the right-hand spiral rule, and the armature made of ferromagnetic material is sucked down until the air gap is equal to zero. Driven by the armature, the normally open contact of the relay The point is closed, and the normally closed contact is opened, thus completing the closing process of the relay.
Working principle of time relay
The relay manufacturer tells you that the time relay is mainly realized by the electromagnetic principle, and sometimes relays are also realized by the mechanical principle, and the corresponding equipment is controlled by the time relay. When the coil of the time relay is energized, a part of the time relay is first attracted by the iron core, which will directly cause the iron core to move down for an instant, and then realize the function of turning on or off. And when the piston rod in the time relay is under the elastic force of the spring, it will move downward at this time, and then the piston rod will slowly descend under a certain force.
Working principle of intermediate relay
A coil is installed in the u-shaped magnetizer of the intermediate relay. There is an armature on the magnetizer and two rows of contact pieces on both sides. When the armature is not moving, lift the armature up to keep a certain distance between the armature and the magnetizer. gap and balance.
When the electromagnetic torque in the gap exceeds the reaction torque, the armature will attract the guide magnet and press the contact shrapnel to close under the action of the electromagnetic force, separate the normally closed contact from it, and close the normally open contact. When the coil is powered off, the moving contact is reset under the action of the spring. When the circuit is energized, the electromagnetic force and the moving iron core are run in to guide the contacts to start, so that the normally closed contacts of the relay can be separated and the normally open contacts can be closed. When the intermediate relay circuit is de-energized, the internal spring acts to reset the movable contact.
Relay manufacturers share expanded knowledge:
Working principle of magnetic latching relay
The contact of the magnetic latching relay is in a stable state under the influence of the magnetic force of the permanent magnet. If it is necessary to change the switching state of the contact, it is only necessary to apply a DC pulse voltage to the coil.
Working principle of optocoupler relay
The optocoupler relay is a solid-state relay, and the optocoupler is used to drive the thyristor to control the optocoupler end to give a suitable electrical signal. 20mA), in this way, the phototransistor at the other end of the optocoupler gets signal conduction, which drives the thyristor to conduct.
Features of Time Relay
1. The air in the time relay can affect the time relay. The time relay can also swing up and down with a delay according to the resistance generated by a certain volume of air. The time relay has a simple structure and is expensive, but in terms of performance, the time relay is accurate. The degree is very high.
2. The delay time of some time relays is very short, as short as even a few tenths of a second. Compared with such time relays, the structure is generally simpler in general, and they are usually used in DC circuits.
3. There is a time delay that is electric. The principle of this time relay is similar to the current clock and watch. The internal motor of the electric time relay can effectively drive the reduction gear to realize the functions of other time relays. Compared with other time relays, this kind of relay has high delay accuracy, and the corresponding price is relatively expensive.
4. The transistor-type time relay has the characteristics of small size, and because it is super convenient to use, it is the most common one now.
If some friends don’t have a deep understanding of time relays, they don’t know that time relays have a history of decades. From the initial disadvantages of large size, bulkiness, troublesome operation, and high price, it has developed into today's various time relays, and while continuously improving product quality, the volume of time relays is also constantly decreasing. We hope that more and better products will appear in our field of vision in the future. The above is the introduction of some relevant information about relays by relay manufacturers. I hope it will be helpful to you.