What is an electromagnetic relay used for

Relay is an electronic control device, it has a control system (also known as an input loop) and a controlled system (also known as an output loop), usually used in automatic control circuits, it is actually a kind of "automatic switch" to control a larger current with a smaller current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit. 1. The working principle and characteristics of electromagnetic relays Electromagnetic relays are generally composed of iron cores, coils, armature irons, contact reeds, 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 to attract the core, thereby driving the dynamic contact of the armature to engage with the static contact (normally open contact). When the coil is de-energized, the electromagnetic suction force disappears, and the armature returns to its original position under the reaction force of the spring, so that the moving contact engages with the original static contact (normally closed contact). In this way, it is engaged and released, so as to achieve the purpose of conduction and cutting in the circuit.

For the "normally open, normally closed" contacts of relays, they can be distinguished as follows: the static contacts that are in the open state when the relay coil is not energized are called "normally open contacts"; Static contacts that are turned on are called "normally closed contacts". 2. The working principle and characteristics of the thermal reed relay The thermal reed relay is a new type of thermal switch that uses thermal magnetic materials to detect and control the temperature.

It consists of a temperature-sensing magnetic ring, a constant magnetic ring, a reed switch, a thermally conductive mounting sheet, a plastic substrate and some other accessories. Thermal reed relays do not use coil excitation, but are driven by the magnetic force generated by the constant magnetic ring. Whether the constant magnetic ring can provide magnetic force to the reed switch is determined by the temperature control characteristics of the thermosensitive magnetic ring.

3. The working principle and characteristics of the solid-state relay (SSR) The solid-state relay is a four-terminal device with two terminals as the input terminal and the other two terminals as the output terminal, and the isolation device is used in the middle to realize the electrical isolation of the input and output. Solid state relays can be divided into AC type and DC type according to the type of load power supply. According to the switch type, it can be divided into normally open type and normally closed type.

According to the isolation type, it can be divided into hybrid type, transformer isolation type and optoelectronic isolation type, with the optoelectronic isolation type being the most.

It is a large power switch, which uses a small current to control the switch through a large current switch.

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.); There is an actuator (output part) that can realize "on" and "off" control of the controlled circuit; 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.

.As a control element, in summary, the relay has the following functions:

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

.2) Zoom in. For example, sensitive relays, intermediate relays, etc., can control a very large power circuit with a very small amount of control.

.3) Composite signals. For example, when a plurality of roll control deficit signals are input into a multi-winding relay in the prescribed form, a predetermined control effect is achieved after comparison and synthesis.

.4) Automatic, remote control, monitoring. For example, relays on automatic devices, together with other electrical appliances, can form a program control circuit to achieve automatic operation.

The factory specializes in the production of all kinds of time relays, electromagnetic relays, electronic relays, high-power relays, liquid level relays, solid-state relays, high-power relays, small relays, timers, counters, relays, etc.

A relay is a device that uses the on/off of low-voltage and weak-current circuits to indirectly control high-voltage and high-current circuits. Electromagnetic relay is a kind of switch that uses electromagnets to control the working electric filial piety.

When the protected element of the power system fails, the relay protection device should be able to automatically, quickly and selectively remove the faulty component from the power system, so as to ensure that the fault-free part quickly recovers normal operation and prevents the faulty element from continuing to suffer damage. reduce the scope of power outages; By the early 90s, the development, production and application of integrated circuits and large-scale integrated circuit protection were in a dominant position, and the era of computer relay protection for intelligent information processing is currently being studied.