The difference between AC contactor and relay
1, which have the same working principle and control mode.
2. Contactor is usually used as the main actuator of control circuit. Contacts are divided into two parts, the main part and the auxiliary part. The number of contacts is small, the contact capacity is large, and the ability to make and break loads is large. In large capacity, there is usually an arc extinguishing cover to enhance the on-off ability. In addition, it has 1-2 pairs of auxiliary contacts for control.
3. Relays have a large number of normally open and normally closed contacts, small capacity and no distinction between main and auxiliary contacts, and are generally used for continuous conversion in the control loop.
4. The contact capacity of general relays will not exceed 5A, and that of small relays is only 1A or 2A, while the minimum contact capacity of contactors is 10A to 20A. 5. The coil of relay can be divided into DC and AC, while the coil of contactor only has AC; 6. Contactors usually have three main contacts and several auxiliary contacts, while relay contacts generally do not distinguish between main contacts and auxiliary contacts; 7. The contacts of relays are sometimes set in pairs, that is, normally open contacts and normally closed contacts are combined into one, while the main contacts of relays are normally open contacts and will not be set in pairs; 8. According to specific requirements, relays will be combined with other devices to design time relays and pressure relays. , with additional functions, and contactors generally do not have additional functions. Electromagnetic relay and contactor, their working principles should be said to be the same. Sometimes the same device is used as a contactor in this circuit and a relay in another circuit. How to distinguish? The way to distinguish them is to look at their specific uses.
The main function of relay is to detect, transmit, transform or process signals, and the current of its on-off circuit is usually very small, that is, it is generally used in control circuits (with? Main circuit? Contrast).
What's the difference between AC contactor and relay?
1, instead of small contactor
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 electric rolling gates and the control of some small household appliances. This advantage is that it can not only achieve the purpose of control, but also save space and make the control part of electrical appliances more exquisite.
2. Increase the number of contacts
This is the most common use of intermediate relay, for example, when the contact of a contactor needs to control multiple contactors or other components in the circuit control system, an intermediate relay is added to the line.
3, increase the contact capacity
We know that the contact capacity of the intermediate relay is not very large, but it also has a certain load capacity, and the current required for its driving is very small, which can be used to expand the contact capacity. For example, it is usually impossible to directly control electrical components with relatively heavy loads with the outputs of inductive switches and triodes. Instead, an intermediate relay is used in the control circuit to control other loads through the intermediate relay, so as to achieve the purpose of expanding the control capability.
4. Change the contact type
In the industrial control circuit, it often happens that the normally closed contacts of the contactor are needed to achieve the control purpose, but the normally closed contacts of the contactor itself have been used up and the control task cannot be completed. At this time, an intermediate relay can be connected in parallel to 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 to achieve the required control purpose.
5, used as a switch
In some control circuits, the on-off of some electrical components is often controlled by the opening and closing of their contacts, such as the common automatic degaussing circuit in color TV or display. The transistor controls the on-off of the intermediate relay, thus controlling the on-off of the degaussing coil.
6, eliminate the interference in the circuit
In industrial control or computer control lines, although there are various interference suppression measures, the interference phenomenon still exists more or less.
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