The vacuum interrupter is mainly used in power transmission and distribution control system, also used in metallurgy, mining, petroleum, chemical, railway, broadcasting, communications, industrial high-frequency heating and other power distribution systems. It has the characteristics of energy saving, material saving, fire prevention, explosion-proof, small size, long life, low maintenance cost, reliable operation and no pollution.

The airtight insulating shell made of glass or ceramics, the moving end cover, the fixed end cover, and the stainless-steel bellows form an airtight insulating system.

The stainless-steel bellows can not only isolate the vacuum state inside the vacuum interrupter from the external atmospheric state, but also enable the moving contact and the moving conductive rod to move within a specified range to complete the closing and breaking operations of the vacuum switch.

1. Prevent the contacts from producing a large amount of metal vapor and droplet splashing during the arcing process, polluting the inner wall of the insulating housing, and avoiding the reduction of the insulating strength of the vacuum interrupter housing or flashover.

2. Improve the electric field distribution inside the vacuum interrupter, which is beneficial to the miniaturization of the vacuum interrupter insulation shell, especially for the miniaturization of the high-voltage vacuum interrupter.

3. Absorb part of the arc energy and condense arc products. Especially when the vacuum interrupter is breaking short-circuit current, most of the heat energy generated by the arc is absorbed by the shielding system, which is beneficial to improve the recovery strength of the medium between the contacts. The greater the amount of arc products absorbed by the shielding system, the greater the energy absorbed by the shielding system, which has a good effect on increasing the breaking capacity of the vacuum interrupter.

1. High breaking capacity. The material itself is required to have high electrical conductivity, small thermal conductivity, large heat capacity and low thermionic emission capability.

2. High breakdown voltage. The higher the breakdown voltage, the higher the dielectric recovery strength, which is beneficial to arc extinguishing.

3. High resistance to electrical corrosion. That is, it can withstand the ablation of the arc, and the amount of metal evaporation is small.

4. Anti-welding ability.

5. Low cut-off current value, hopefully below 2.5A.

6. Low gas content. Among them, low gas content is a requirement for materials used inside all vacuum interrupters. Especially for copper, oxygen-free copper with low gas content must be required for special processing. The solder, etc. are made of silver and copper alloys.

The contact materials of vacuum interrupters for circuit breakers are mostly copper-chromium alloys, with copper and chromium each accounting for 50%. A copper-chromium alloy sheet is welded on the butt surfaces of the upper and lower contacts, and the thickness is generally 3mm. The rest is called the contact seat, which can be made of oxygen-free copper.

The vacuum interrupter is an electric vacuum device that uses a high vacuum working insulating arc extinguishing medium and relies on a pair of contacts sealed in the vacuum to realize the on-off function of the power circuit.