When the circuit breaker cuts and closes, an arc is generated between the moving and static contacts. The arc temperature is very high. If it cannot be extinguished within a limited range as soon as possible, nearby parts will be damaged. For high voltage arcs, due to the high recovery voltage , It is very difficult to simply cut off the arc in the air, so all high voltage circuit breakers are equipped with various arc extinguishing devices. The function of the arc extinguishing device is to rapidly increase the strength of the arc gap medium and extinguish the arc as soon as possible.
At the moment when the contacts of the electrical device are opened and closed, if the load power is large, the arc will appear. If there is no arc extinguishing device to cut off the arc or cool it out, the arc short circuit or grounding may occur, which is very dangerous, so the arc extinguishing device Is used to extinguish the arc,
The arc extinguishing methods generally include: slit arc extinguishing, cooling arc extinguishing, magnetic blowing arc extinguishing, rapid pull arc extinguishing and other forms.