Do you know the relay? Some people may not know the name of the product, but they often see it in daily electricity consumption, and there are many brands of relays, such asFinder intermediate relay, is a brand product in the industry. Today, I'd like to introduce you to the knowledge of relays and some commonly used relays. The relay is an electrical control device. When the change of input quantity meets the specified requirements, the controlled quantity in the electrical output circuit changes within the predetermined steps. It has an interactive relationship between the control system (also known as input loop) and the controlled system (also known as output loop). Usually used in automatic control circuit, it is actually an "automatic switch", which uses low current to control high current operation. It plays the role of automatic regulation, safety protection, conversion circuit, etc,

　　There are many kinds of relays

According to the input quantity, it can be divided into voltage relay, current relay, time relay, speed relay, pressure relay, etc

According to the working principle, it can be divided into electromagnetic relay, inductive relay, electrical relay, electronic relay, etc

According to the change form of input quantity, it can be divided into: control relay, protection relay, etc.

The relay is composed of coil, magnetic circuit, reaction spring and contact. After the coil is energized, it can generate electromagnetic suction, drive the armature of the magnetic circuit to engage, and generate displacement and contact. The magnetic circuit is composed of iron core, choke and armature. Its task is to establish a magnetic circuit channel for the magnetic flux generated by the coil. The function of the reaction spring is to provide the armature with a repulsive force in the opposite direction of action. When the coil is de energized, it can help the armature and contact reset. The contact is used for external control output and consists of normally closed contact and normally open contact. After the coil is energized and the relay is pulled in, the normally closed contact opens and the normally open contact closes. After the coil is powered off and released, the normally closed contact and the normally open contact are reset to the initial state.

We take the most commonly used finder intermediate relay as an example. Finder intermediate relay is usually used to transmit signals and control multiple circuits at the same time. It can also be used to directly control small capacity motors or other electric actuators. Finder intermediate relay is essentially a voltage relay, but it has a large number of contacts and small capacity. It is an electric appliance used as a control switch. The electrical part of finder intermediate relay is composed of coil and contact. The power supply of finder intermediate relay solenoid coil is DC and AC. In relay protection and automatic control system, it can be used to expand the number of control contacts and increase the capacity of contacts. In the control circuit, it can be used to transmit signals and control multiple lines at the same time

　　Generally speaking, finder intermediate relay has the following purposes:

① Replace the small contactor

② Increase the number of contacts

③ Increase contact capacity

④ Change over contact type

⑤ Used as a small capacity switch

⑥ Overvoltage change

⑦ Eliminate interference in the circuit

The structure and principle of finder intermediate relay are basically the same as that of AC contactor, but there are differences. What is the difference between finder intermediate relay and contactor? As we all know, the general circuit is usually divided into two parts: the main circuit and the control circuit. The relay is mainly used for the control circuit, and the contactor is mainly used for the main circuit; The relay can realize the function of using one control signal to control another or more signals, and complete the control of start, stop and linkage. The main control object is contactor; The strong current carrying capacity of the contactor is realized by providing strong current to the weak current control object

Finder intermediate relay usually includes 8-pin, 11 pin and 14 pin finder intermediate relay. Here, let's compare the intermediate relays of 8-pin, 11 pin and 14 pin finder to see the difference between them. For example, the 8-pin finder intermediate relays 13 and 14 are the coils of the relay, which are used to connect the power supply. The other six pins 1, 5, 9 and 4, 8 and 12 are two sets of contacts respectively. The difference between the relay and the 14 pin finder intermediate relay is the lack of two sets of contacts. Generally speaking, the voltage level and wiring mode are displayed on the finder intermediate relay. No guidance is required. Generally, 13 and 14 wiring rings are used, and other contacts can be connected according to the mark. 11 pins are slightly different (coils are 10 and 11), but 11 pins are used less.