Arc extinguishing principle of high voltage vacuum circuit breaker

Arc quenching is a process that exists in all circuit breakers. Once the arc extinguishing work is not good, it will cause damage to the lines of electrical equipment, and seriously endanger the safety of life and property. We usually use four methods: mechanical arc extinguishing, slit arc extinguishing, magnetic blowing arc extinguishing and grid arc extinguishing.

1. Mechanical arc extinguishing

By using the limit device to quickly elongate the arc to achieve the purpose of arc extinguishing, this release is commonly used in switching appliances.

2. Magnetic blowing arc extinguishing

Under the influence of the magnetic field generated by the magnetic blowing coil connected in series with the contact, the arc is rapidly elongated under the influence of the magnetic field, and is pulled into the arc extinguishing cover containing the solid medium, and the arc is cooled and extinguished by contact with the solid material.

3. Grid arc extinguishing

When the contacts are separated, the arc is propelled into a set of metal grids under the action of electric power and is divided into several segments. Each of the metal grids insulated from each other becomes an electrode, so there will be a lot of cathode and anode voltage drops. For AC arcs, when close to the cathode, the arc zero-crossing will have a dielectric strength of 150 volts to 250 volts, causing the arc to be unsustainable and extinguished. Because the grid arc extinguishing effect is better in AC appliances than DC appliances, it is widely used in AC appliances.

4. Narrow slit arc extinguishing

Under the action of the magnetic field formed by the arc, the arc is elongated into the narrow slits of the arc extinguishing cover. Several slits divide the arc into several sections and then contact with the solid arc extinguishing material, so that the arc is quickly extinguished. Slit arc extinguishing is mostly used in AC contactors.