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Operation principle of power relay contact

PostTime: 2022-11-01 Views: 878

Operation principle of power relay contact

The action process of the contact can be divided into two parts: contact closing and contact opening, that is, the pull in and release process of the relay. They are cyclically switched at a certain frequency to form contact opening and closing phenomena. In the process of contact closure and disconnection, there will be many special physical and chemical phenomena, such as contact resistance, contact jitter and arc.


Action principle when the contact is closed


When the moving contact and the static contact of the relay collide with each other, contact bounce will occur, that is, uncontrolled intermittent opening and closing. At this time, the arc and Joule heat generated by the energized current greatly affect the opening and closing capacity of the relay.


Action principle when the contact is disconnected


When the contact disconnects and cuts off the load, it will produce dazzling sparks and arcs. The arcs will last until the arc voltage drops below the minimum arc voltage, which will cause greater damage to the contact. However, different contact materials and contact gap size directly affect the emission state of arc electrons and the difficulty of occurrence, so they are important conditions for determining the arc

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