What Is The Difference Between Contactor And Relay?

Contactors and relays are often confused, but they are still different.

The main function of the contactor is to connect or disconnect the main circuit. The main circuit here refers to whether the circuit is connected and working. The main circuit concept here corresponds to the control circuit.

The main function of the relay is signal detection, transmission, conversion or processing. Its switching circuit current is usually small, that is, it is usually used in control circuits.

In short, the contactor belongs to the main circuit element, and its task is to control the on-off of the main circuit. The relay is an auxiliary circuit component, and its task is to perform signal transmission and control the main circuit components.

Typically, the current through the main circuit is greater than the current through the control circuit. Therefore, high-capacity contactors usually have an arc chute. If the working current of a main circuit is very small, it is entirely possible to use a relay as a device for making and breaking the main circuit.

However, if the operating current of a certain main circuit is so large that the capacity of the contactor using that main circuit is very large, the current that makes this contactor work will also be very large, which means that current flows in its control circuit It is very large, and its control circuit is difficult to open and close with ordinary relays. At this time, the contactor can be selected as the switch of the control circuit.

There are many types of relays, mainly used for secondary protection contactors of high current, first of all ferromagnetic coils and main contacts. When the contact capacity of the relay cannot meet the requirements, a contactor can also be used. When the auxiliary contact of the contactor is not enough, a relay can be added as an auxiliary contact to realize various controls.

A relay is an electrical control device, generally speaking, a switch is turned off or turned on when the conditions are met. A relay is actually an automatic switch that uses a smaller current to control a larger current. It plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit. It is widely used in remote control, telemetry, communication, automatic control, mechatronics and power electronic equipment, and is one of the most important control components.

Its basic principle is to use the electromagnetic effect to control the mechanical contact to achieve the purpose of on-off, energize the coil with iron core - the coil current generates a magnetic field - the magnetic field attracts the armature to act on and off the contact.

There are many types of relays, which can be divided into voltage monitoring relay, current monitoring relay, time relay, liquid level relay, phase sequence loss phase relay, etc. according to the input quantity. According to the working principle, they can be divided into electromagnetic relays, inductive relays, electric relays, electronic relays, etc. According to the purpose, it can be divided into control relay, protection relay, etc., according to the change of input quantity, it can be divided into with or without relay and measuring relay.