Relay contact action principle

Update:19-10-2019
Summary:

The action of the contact can be divided into two parts […]

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

Principle of action when the contacts are closed

When the moving contact and the static contact of the single-phase relays are in contact with each other, the contact rebound occurs, that is, the uncontrolled gap opening and closing, and the Joule heat and the energizing current generated by the arc are greatly affected at this time. Relay. The ability to open and close.

Principle of action when the contact is opened

When the contacts are opened and the load is cut, dazzling sparks and arcs are generated, and the arc occurs until the arc voltage drops below the minimum arc voltage value, which causes significant damage to the contacts. Different contact materials and contact gap sizes directly affect the radiation state of the arc electrons and the ease with which they occur, so they are important conditions for determining the arc.