According to different switch types, there are external shield type ceramic vacuum interrupter, intermediate sealed cup-shaped longitudinal magnetic field miniaturized vacuum interrupter, and inner sealed glass bubble interrupter. The basic structure is as follows:
1. airtight insulation system (outer casing)
The hermetic insulation system consisting of a gas-tight insulating cylinder made of ceramic, glass or glass-ceramic, a movable end cover, a fixed end cover, and a stainless steel bellows is a vacuum-tight container. In order to ensure airtightness, in addition to the strict operation process in the sealing type, the material itself is required to have a gas permeability and a small amount of internal gas discharge.
2. conductive system
It consists of a fixed conductive rod, a fixed running surface, a fixed contact, a moving contact, a moving running surface, and a moving conductive rod. There are roughly three types of contact structures: cylindrical contacts, transverse magnetic field contacts with spiral groove running surfaces, and longitudinal magnetic field contacts. At present, the longitudinal magnetic field technology is adopted, and the arc extinguishing chamber has a strong and stable arc breaking capability.
3. shielding system
The shield is an indispensable component in the vacuum interrupter, and has a plurality of main shields, bellows shields, and shroud shields surrounding the contacts. The function of the main shield is to prevent the arc product from splashing onto the inner wall of the insulating casing during the arcing process, thereby reducing the insulation strength of the casing. b Improve the uniformity of the electric field distribution inside the arc extinguishing chamber, which is beneficial to reduce the local field strength and promote the miniaturization of the vacuum interrupter. c Condensing the arc product, absorbing a part of the arc energy, contributing to the recovery of the strength of the medium after the arc gap.