The main functions of the intermediate relay include replacing small contactors, increasing the number of contacts, increasing the capacity of contacts, being used as switches, converting voltage, and eliminating circuit interference. There are still many functions of the intermediate relay. Let's explore them together.

中间继电器的主要作用

Main functions of intermediate relay

中间继电器作为继电器的一种，它的原理和交流接触器一样，都是由固定铁芯、动铁芯、弹簧、动触点、静触点、线圈、接线端子和外壳组成。

As a kind of relay, the principle of intermediate relay is the same as that of AC contactor, which is composed of fixed iron core, moving iron core, spring, moving contact, static contact, coil, terminal and shell.

线圈通电，动铁芯在电磁力作用下动作吸合，带动动触点动作，使常闭触点分开，常开触点闭合；线圈断电，动铁芯在弹簧的作用下带动动触点复位。

When the coil is electrified, the moving iron core acts to pull in under the action of electromagnetic force, and the moving contact acts to separate the normally closed contact and close the normally open contact; When the coil is powered off, the moving iron core drives the moving contact to reset under the action of the spring.

一、代替小型接触器

1、 Replace small contactor

中间继电器的触点具有一定的带负荷能力，当负载容量比较小时，可以用来替代小型接触器使用，比如电动卷闸门和一些小家电的控制。

The contact of the intermediate relay has a certain load capacity. When the load capacity is relatively small, it can be used to replace small contactors, such as the control of electric rolling gate and some small household appliances.

优点：不仅可以起到控制的目的，而且可以节省空间，使电器的控制部分做得比较精致。

Advantages: not only can play the purpose of control, but also can save space, so that the control part of electrical appliances do more delicate.

二、增加接点数量

2、 Increase the number of contacts

这是中间继电器最常见的用法，例如，在电路控制系统中一个接触器的接点需要控制多个接触器或其他元件时而是在线路中增加一个中间继电器。

This is the most common usage of the intermediate relay. For example, in the circuit control system, when the contact of a contactor needs to control multiple contactors or other components, an intermediate relay is added to the circuit.

三、增加接点容量

3、 Increase contact capacity

中间继电器的接点容量虽然不是很大，但也具有一定的带负载能力，同时其驱动所需要的电流又很小，(www.dgjs123.com电工技术之家)因此，可以用中间继电器来扩大接点容量。比如一般不能直接用感应开关、三极管的输出去控制负载比较大的电器元件。而是在控制线路中使用中间继电器，通过中间继电器来控制其他负载，达到扩大控制容量的目的。

Although the contact capacity of the intermediate relay is not very large, it also has a certain load capacity, and the current required for its drive is very small（ www.dgjs123.com Therefore, the intermediate relay can be used to expand the contact capacity. For example, the output of inductive switch and triode can not be used to control the electrical components with large load. Instead, the intermediate relay is used in the control circuit to control other loads, so as to expand the control capacity.

四、转换接点类型

4、 Change over contact type

在工业控制线路中，常常会出现这样的情况，控制要求需要使用接触器的常闭接点才能达到控制目的，但是接触器本身所带的常闭接点已经用完，无法完成控制任务。这时可以将一个中间继电器与原来的接触器线圈并联，用中间继电器的常闭接点去控制相应的元件，转换一下接点类型，达到所需要的控制目的。

In the industrial control circuit, such a situation often occurs. The control requires the use of the normally closed contact of the contactor to achieve the control purpose, but the normally closed contact of the contactor itself has been used up, so it is unable to complete the control task. At this time, an intermediate relay can be paralleled with the original contactor coil, and the normally closed contact of the intermediate relay can be used to control the corresponding components, and the contact type can be changed to achieve the required control purpose.

五、用作开关

5、 Used as a switch

在一些控制线路中，一些电器元件的通断常常使用中间继电器，用其接点的开闭来控制，例如如彩电或显示器中常见的自动消磁电路，三极管控制中间继电器的通断，从而达到控制消磁线圈通断的作用。

In some control circuits, intermediate relay is often used to control the on-off of some electrical components, such as the common automatic degaussing circuit in color TV or display. Triode controls the on-off of intermediate relay, so as to control the on-off of degaussing coil.