What is an intermediate relay ?

Relay is a small yet important electrical device in electrical circuits. There are different types of the relay. In this article, we will learn basic information about the intermediate relay.

what is an intermediate relay?

Intermediate relay is a small electromagnetic relay device. They have the function of switching control signals or amplifying tasks. In the control scheme, the intermediate relay is normally installed in the intermediate position. It is between small power control devices and larger capacity devices.

Types of intermediate relay

Currently, on the market you can easily find the following intermediate relay types:

  • 5V , 12V, 24V (DC) intermediate relay
  • 8 pin, 14 pins intermediate relay

Relay trung gian Idec RU4S-D24

Idec RU4S-D24 intermediate relay

Structure and operation principle of the intermediate relay

Here, we will learn about the structure and operation principles of intermediate relay for proper use.

The structure of the intermediate relay

This electromagnet device has a design including dynamic steel core, static steel core and a coil. The inner coil can be an intensity coil, voltage coil, or both. The steel core is driven by the spring and positioned by an adjustment screw. The contact mechanism includes forward contact and reverses contact.

Mô hình hoạt động của relay trung gian

the intermediate relay inside a circuit

Principle of operation

The current flowing through the intermediate relay will run through the inner coil. It creates a magnetic field. This suction magnetic field acts on an internal lever. This phenomenon closes or opens electrical contacts. From there it will change the state of the relay. The number of electrical contacts changed maybe 1 or more, depending on the design.

Relay has 2 independent circuits that work. A relay control coil: Is the current running through the coil (or does it mean relay control in the ON or OFF state). A control circuit should be controlled whether or not the current goes through the relay based on the ON or OFF status of the relay.

Nguyên lí hoạt động của relay trung gian

Operation principle of an intermediate relay

Uses of the intermediate relay

The use of the intermediate relay is to do the  “intermediate” task of relaying the circuit to another device. For example, the refrigerator protector. When the power is low, the relay will disconnect the power, not for the cabinet. When electricity is stable, it will power again normally. In the motorbike and car battery charger, when the generator is strong enough, the intermediate relay will close the charging circuit for the battery.

Application of intermediate relay in nowaday

The intermediate relay has a lot of contacts (4-6 contacts). These contacts can be both open and closed. So this device is often used to transmit signals when the main relay does not guarantee the ability to close or interrupt. In addition, the intermediate relay is also used to divide signals to many other parts from a main relay in the control circuit diagram.

Bảng mạch điện tử tích hợp relay trung gian

Electronic circuit board integrated the intermediate relay

In addition, the intermediate relay is also often used to transmit signals to the rear
circuit unit by making the output element. On the other hand, they can also isolate different voltages between the actuator and the controller. The Executive part is usually AC. It has a high voltage (220V – 380V). The control part is usually DC voltage. It has a low voltage (9V – 24V).
People often use only the intermediate relay for signal or current transmission that is worth several ampere or less. For larger streams (several tens of ampere becomes) with an integrated arc chamber, we must use a contactor.
Hopefully, the information on the intermediate relay helps you better understand this device. See you later in the following articles.