Relays and contactors are electromagnetic switching devices, but the former belong to switching devices working in the control circuit, while the latter belong to switching devices working in the main circuit.
Definition of relay: NB90 Relay is an automatic electrical appliance. It is suitable for long-distance connection and disconnection of AC and DC small capacity control circuits, and is used for control, protection and signal conversion in electric drive systems. The input quantity of the control relay is usually electricity such as current and voltage, and it can also be non-electric quantity such as temperature, pressure, and speed. The output quantity is the electrical signal or parameter change of the output circuit when the contact operates. The characteristic of the relay is that when its input quantity changes to a certain program, the output quantity will change stepwise.
Let me tell you as a Power Relay Manufacturer.
1. The effect is different:
The primary function of a relay is for signal detection, transmission, conversion, or disposal. The circuit current of the relay is generally small, and it is generally used in control circuits to control weak signals.
The primary function of the contactor is to connect or disconnect the main circuit. The main circuit refers to whether a circuit is working or not is marked by whether the circuit is on or off. The main circuit concept corresponds to the control circuit. Generally, the current passed by the main circuit is larger than that of the control circuit.
Large-capacity contactors are generally equipped with arc extinguishing hoods. The contact capacity of the relay generally does not exceed 5A, the contact capacity of small relays generally only needs 1A or 2A, and the smallest contactor has a contact capacity of 9A; the contactor's contacts generally have three pairs of main contacts (main contact The heads are always open contacts) There are also several pairs of auxiliary contacts.
The contacts of the relay are generally not divided into main and auxiliary; the contacts of the relay are sometimes arranged in pairs, that is, the normally open contacts and the normally closed contacts are combined, and the contactors are not arranged in pairs; the relays will meet specific needs. Combined with other equipment to plan time relays, counters, pressure relays, etc., have additional functions, while contactors generally do not.
2. Contact opening and closing are different:
In addition, the contactor is used to connect or disconnect the load with higher power. It is used in the (power) main circuit. The main contact can have interlocking contacts to indicate the opening and closing of the main contact. Relays are generally used in electrical control circuits to expand the contact capacity of miniature or small relays to drive larger loads.
For example, the contacts of a relay can be used to switch on or off the contactor's coil. Generally, the relay has more opening and closing contacts. Of course, the relay can also perform certain special functions, such as logic operations, through proper connection.
3. There is one arc extinguishing device: In fact, the most important difference between contactors and relays is that the contactors have arc extinguishing devices, while the relays do not.
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