The vacuum interrupter is mainly composed of airtight insulation system, conductive system, shielding system and contact system.

1. Outside insulation

Material: The materials of the insulating shell are glass, ceramics and glass-ceramic. Glass-ceramic is expensive, so it has not been practically used; glass has poor structural strength, and its usage has gradually decreased; ceramics have the best comprehensive performance and are therefore the most widely used.

Main function: The insulating shell mainly plays the role of insulating support and participates in forming an airtight insulating system.

2. Bellows

Material: The bellows is mainly made of stainless steel with a thickness of 0.1-0.2mm.

Main function: The bellows is mainly responsible for the movement of the moving electrode within a certain range and the function of high vacuum sealing. Vacuum quenching requires a high mechanical life of the bellows.

3. Shielding cylinder

Material: The shielding cylinder can be made of oxygen-free copper, stainless steel, electrical pure iron or copper-chromium alloy and other materials.

main function:

1) Reduce the contamination of the inner wall of the insulating shell caused by the metal vapor and droplet splashing generated by the contact during the arcing process, so as to avoid the decrease of the insulating strength of the vacuum interrupter shell or the occurrence of flashover.

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

3) Condensation of 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 condensed arc products in the shielding cylinder, the greater the absorbed energy, and the better the breaking capacity of the vacuum interrupter can be improved.