They can find out what purpose, principle of operation and device of the intermediate relay. Very often this device is used in circuits, but not everyone has an idea of ​​​​how it works and what it is used for. So let's take a closer look at each question.

Purpose

Intermediate relays are widely used in automation and control systems (see photo below). These devices switch control signals, control powerful devices, separate control circuits from power circuits and perform no less important role than power relays.

The intermediate relay got its name because of its position in the automation and control circuits. They are located between the source of the task and the actuator, such as a contactor, so it becomes clear why the relay was called that.

You can get more information about the purpose and varieties of products by watching this video:

Description of the range

Device

These devices come in all types and sizes. From miniature relays with two contacts, to several dozen in a repeater relay. In all of them, the constructive principle is the same. Intermediate relay device is presented ean electromagnetic control coil, a magnetic circuit, a spring mechanism and a group of contacts. You can learn more about the design of the device by viewing the picture below:

The industry produces a wide range of devices for a variety of control voltages from 5 volts to 220. They can be designed for alternating "AC" voltage and constant "DC".

Outwardly, they are practically no different. The difference is only in the design of the magnetic circuit. For alternating current, it is recruited from a group of plates, and for direct current, it is one-piece. This is done to reduce heating losses in the magnetic circuit during the passage of alternating current.

As for the technical characteristics of devices, they are different for each type. For example, for the RE series, they will look like:

For industrial purposes, pads are made for intermediate relays with installation on. Relays and sockets for them are also available with a wide range of connector types. This is done for ease of operation within the same device, when there are models of different voltages, and due to inattention, one type has not been replaced by another.

Principle of operation

It is equally important to know how the intermediate relay works. The principle of operation is as follows: when voltage is applied to the control coil, the magnetic flux that appears in the core draws in the contact mechanism. The latter, in turn, change position, and switch, while opening or closing the contacts.

You can learn more about the principle of operation by watching this video:

How REC 73/3 works

Application area

Intermediate relays are used in control circuits for switching power circuits from a low current source. They are also needed to assemble a contact retention circuit, signal repetition and output to indicators, duplication to remote control panels, etc.

Very often, these devices are used in emergency systems, industrial equipment, relay protection devices and electric power facilities.

For example, let's take a control circuit for an asynchronous motor, with control of the presence of a phase. This circuit is assembled on intermediate relays of the type 1RN, 2RN, 3RN, 1RP, 2RP, as well as with repetition on the light indicators of the state of the phases. By the way, immediately pay attention to the symbol of this element on the diagram.