What is the working principle of the relay and what should be paid attention to when working

The permanent magnet is kept in a released state, and after the working voltage is added, the electromagnetic induction causes the armature and the permanent magnet to produce attraction and repulsion moments, resulting in downward motion, and finally reaching the state of engagement. Relay is a kind of contact (or circuit) that turns on or off AC and DC small-capacity control loops when the input quantity changes to a certain value.

The relay consists of an iron core, a coil, an armature, a contact reed, etc. As long as a certain voltage is added to both ends of the first circle, a certain current will flow through the coil, resulting in an electromagnetic effect, and the armature will overcome the tensile force of the return spring under the action of electromagnetic force attraction and attract to the iron core, thereby driving the dynamic contact of the armature to engage with the static contact (normally open contact).

The safety relay is composed of several relays and circuits, in order to complement each other's abnormal defects, to achieve the complete function of the relay wide grinder with correct and low malfunction, so that the lower the error and failure value, the higher the safety factor, so it is necessary to design a variety of safety relays to protect different levels of machinery, the main goal is to protect the mechanical operators who are exposed to different levels of danger.

The so-called "safety relay" is not a "relay without a fault", but a regular action in the event of a fault, and it has a forced guide contact structure to ensure safety in the event of contact fusion, which is completely different from general relays.

The main spike of the relay should be divided into the coil part and the contact part, when the coil guess part is energized, it will produce magnetic force, so as to attract the contact part to move, and the contact is equivalent to the switch being turned on.

The working principle of the relay is that when an input quantity (such as voltage, current, temperature, speed, pressure, etc.) reaches a predetermined value, it will be made to act to change the working state of the control circuit, so as to achieve the established purpose of control or protection. In this process, the relay mainly plays the role of transmitting signals.

The role of the relay:

1. Expand the control range: for example, when the control signal of the multi-contact relay reaches a certain value, it can be changed, interrupted and connected to multiple circuits at the same time according to the different forms of the contact group.

2. Amplification: For example, sensitive relays, intermediate relays, etc., can control very high-power circuits with a very small control quantity.

3. Comprehensive signal: for example, when a plurality of control signals are input into a multi-winding relay in the specified form, the predetermined control effect is achieved after comparative synthesis.

4. Automatic, remote control and monitoring: For example, the relay on the automatic device can be combined with other electrical appliances to form a program control circuit, so as to achieve automatic operation.

The main working principle of the relay is: when the change of the input quantity (excitation quantity) reaches the specified requirements, it is an electrical appliance that makes the controlled quantity change in the electrical output circuit with a predetermined step change. It has an interactive relationship between the control system (also known as the input loop) and the controlled system (also known as the output loop).

Usually used in the control circuit of automation, it is actually a kind of "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

The relay is an automatic switching element with isolation function, which is widely used in remote control, telemetry, communication, automatic control, mechatronics and power electronic equipment, and is one of the most important control components.

Relays generally have an induction mechanism (input part) that can reflect certain input variables (such as current, voltage, power, impedance, frequency, temperature, pressure, speed, light, etc.); Between the input and output parts of the relay, there is also an intermediate mechanism (drive part) that couples and isolates the input quantity, processes the function, and drives the output part. (Photo by Zhang Xia 1 of Pacific Automobile Network).

What is the working principle and function of relays? Intermediate Relay: Used in relay protection and automatic control systems to increase the number and capacity of contacts.

It is composed of a fixed iron core, a moving iron core, a spring, a moving contact, a static contact, a coil, a terminal block and a housing. After the coil is energized, the moving iron core moves and engages under the action of electromagnetic force, driving the action of the moving contact, separating the normally closed contacts and closing the normally open contacts; The coil is de-energized, the moving iron core drives the moving contact to reset under the action of the spring, and the working principle of the relay is that when a certain input quantity (such as voltage, current, temperature, speed, pressure, etc.) reaches a predetermined value, it will act to change the working state of the control circuit, so as to achieve the established purpose of control or protection. It is used to transmit intermediate signals in control circuits.

For example, in a circuit, a certain contactor of the Quehui type only has two sets of normally open auxiliary contacts, but this circuit needs to use three sets of normally open auxiliary contacts of this contactor, which is not enough, what should I do? You can add an intermediate relay with a plurality of normally open contacts, use one of the groups of normally open contacts of the contactor to control the intermediate relay coil, when the contactor is energically engaged, the normally open contact is closed, and the intermediate relay will be engaged, and then the normally open contact of the intermediate relay is used as the auxiliary contact of the contactor. This is an increase in the number of contacts.

In fact, the structure and principle of intermediate relays and contactors are basically the same, and their main differences are: the contactor has a main contact that can pass through a larger current, and can control the main loop current of the motor and other loads. The contact capacity of the intermediate relay is generally small, in other words, there is no main contact, because the overload capacity is relatively small, all are auxiliary contacts, and the characteristic is that there are more contacts.

Therefore, Bizhi, intermediate relays are generally used in control loops. Generally, it is powered by DC power supply. A few use AC power.