Intermediate relay is used in relay protection and automatic control system to increase the number and capacity of contacts. It is also used to transmit intermediate signal in control circuit. There are two main delay modes of intermediate relay, which are power on delay and power-off delay. The installation modes are mainly divided into fixed, protruding, embedded and rail type. It generally has no main contact, because the overload capacity is relatively small. So it uses all auxiliary contacts, the number is more.

ABB中间继电器就是个继电器，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。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。

ABB intermediate relay is a relay, which is composed of fixed iron core, moving iron core, spring, moving contact, static contact, coil, terminal and shell. 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.

工业控制线路和现在的家用电器控制线路中，常常会有中间继电器存在，对于不同的控制线路，中间继电器的作用有所不同，其在线路中的作用常见的有以下几种。

Industrial control circuit and the current home appliances control circuit, there are often intermediate relays, for different control circuits, the role of intermediate relays are different, the common role in the circuit are the following.

1、作用之一--代替小型接触器

1. One of the functions -- to replace the 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。这样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。

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

2、作用之二--增加接点数量

2. The second function is to increase the number of contacts

在电路控制系统中，线路中增加一个中间继电器，不仅不会改变控制形式、增加接点数量，而且便于维修。

In the circuit control system, adding an intermediate relay in the circuit not only does not change the control form and increase the number of contacts, but also is convenient for maintenance.

3、作用之三--增加接点容量

3. The third function is to increase the 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，因此可以用中间继电器来扩大接点容量。而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. At the same time, the current required for its drive is very small, so the intermediate relay can be used to expand the contact capacity. The intermediate relay is used in the control circuit to control other loads, so as to expand the control capacity.

4、作用之四--转换接点类型

4. Function 4 -- type of transfer contact

在工业控制线路中，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，可以实现需要使用接触器的常闭接点才能达到控制目的。

In the industrial control circuit, 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, so that the normally closed contact of the contactor can be used to achieve the control purpose.

5、作用之五--用作开关

5. Function 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。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, the on-off of some electrical components often uses the intermediate relay, which is controlled by the opening and closing of its contact. For example, in the common automatic degaussing circuit of color TV or display, the triode controls the on-off of intermediate relay, so as to control the on-off of degaussing coil.

6、作用之六--转换电压

6. Function 6 -- switching voltage

在工业控制线路控制线路中电压是DC24V，而电磁阀的线圈电压是AC220V，安装一个中间继电器，可以将直流与交流、高压与低压分开，便于以后的维修并有利于安 全使用。

In the industrial control circuit, the voltage of the control circuit is DC24 V, while the coil voltage of the solenoid valve is AC220 v. installing an intermediate relay can separate DC from AC, high voltage from low voltage, which is convenient for future maintenance and safe use.

7、作用之七--消 除电路中的干扰

7. The seventh function is to eliminate the interference in the circuit

在工业控制或计算机控制线路中，虽然有各种各样的干扰抑 制措施，但干扰现象还是或多或少地存在着，在内部加入一个中间继电器，可以达到了消 除干扰的目的.

In the industrial control or computer control circuit, although there are various interference suppression measures, the interference phenomenon still exists more or less. Adding an intermediate relay inside can achieve the purpose of eliminating interference