Relays are used for control loops. A relay often has several pairs of normally open/closed nodes, which can be used for different control loops. Its nodes can not pass through large currents and are generally not used for power loops. Contactors are similar to circuit breakers, which use weak current to control the switching on or off of strong electricity, mainly for power loops.

Firstly, it is explained that AC contactors are generally divided into main contacts and auxiliary contacts. The main contacts are used to connect and disconnect the main power supply circuit of low-voltage electrical equipment, which has relatively large contact capacity. The auxiliary contacts are used in the control circuit. They are usually open and closed. Because the current in the control circuit is relatively small, the capacity of the auxiliary contacts is much smaller than that of the main contacts.

The relay is only used in control and protection circuits, but it can control high current and high voltage equipment with small current and low voltage in the circuit. It can also expand the capacity of contacts when the capacity and quantity of contacts are insufficient.

According to the different functions of relays, they can play different roles in the control circuit, such as time relay, current relay, voltage relay, intermediate relay, signal relay and so on. The coils of relays can be divided into voltage, current, direct current and alternating current. They are used in different circuits according to the requirements of the circuits. Because the current of these circuits is generally small, the contact capacity of relays is relatively small, so they can not be directly used in the main power circuit.

1. The contact capacity of the relay will not exceed 5A in general. The contact capacity of the small relay is only 1A or 2A in general, and the contact capacity of the contactor is the smallest from 10A to 20A.

2. Relay coils are divided into DC and AC, while contactor coils are AC only; www.diangon.com

3. The contacts of contactors usually have three main contacts and several auxiliary contacts, while the contacts of relays are generally independent of main contacts and auxiliary contacts.

4. The contacts of relays are sometimes set in pairs, i.e. the normally open contacts and the normally closed contacts are combined together, while the main contacts of relays are usually always open contacts, not in pairs.

5. For specific requirements, relays will be combined with other devices to design time relays, pressure relays and so on. They have additional functions, while contactors generally do not have additional functions.

Working Principle: The coil of contactor is connected to the control loop of low voltage equipment. When the voltage of both ends of the coil reaches 70% of the rated value, the core magnetically saturates the armature and drives its main contact point to connect the main power supply to the electrical equipment. When the coil of contactor loses power, the armature is released and the main contact point disconnects and cuts off the main power supply of the equipment.

The coil of relay is connected to the corresponding circuit according to the difference of DC, AC, current and voltage. When the condition of coil suction is satisfied, the armature is sucked in and the corresponding action of its normally open and closed contacts is driven. It plays different roles in the circuit. Some relays can be charged for a long time, while others can not, so some relays in the circuit will not cause the outage of electrical equipment even if they lose power. Transport, and some relays will not cause the start-up operation of the equipment even if the electricity industry.