About relay, contactor, electrical contact and contact

Release time：

2022-10-31 09:47

About relays, contactors, electrical contacts and contacts. I believe all electricians are familiar with electromagnetic relays and contactors. The knowledge about these two kinds of electrical equipment has long been shared by many peers. Today, the author only supplements the contact knowledge of electromagnetic relay and contactor.
The contact burning failure of electromagnetic relay and contactor is a problem we often encounter in our work. The reason for this situation is nothing more than two possibilities: first, the load current flowing through the contact is relatively large, very close to the rated value. Although it does not exceed the rated value of the contact, it is easy to burn the contact after long-term use; In addition, for the above two kinds of electrical equipment, especially the contactor, most of their loads are inductive loads. Although the load current is small, when the contacts are disconnected and released, they are easily damaged by the arc released by the inductive load. As far as electromagnetic relay and contactor contact are concerned, series and parallel connection are very popular in some practical applications. In some electrical circuits requiring interlocking and interlocking control, if a single contact of relay or contactor is used, the relay and contactor may act too fast, which will cause the circuit unable to complete the action state switching. At this time, we can eliminate this phenomenon by connecting two or more contacts of relay and contactor in series, and by increasing the action distance of contacts - extending the action switching time accordingly.
Similarly, it can be known that when the contact capacity of relay and contactor is damaged due to large load current, it can be overcome by expanding the contact in parallel. In a word, the causes of contact burning of electromagnetic relay and contactor are relatively centralized and easy to solve. In the electrical control circuit, we can flexibly use contact wire and parallel connection to solve some practical problems.

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