The vacuum circuit breaker contains three main parts: vacuum interrupter, electromagnetic or spring-operated mechanism, bracket and other components.
Vacuum interrupter
According to the different switch types, there are external shield type ceramic vacuum interrupter, middle sealed cup type longitudinal magnetic field miniaturized vacuum interrupter, and internal sealed glass bubble interrupter, whose basic structures are as follows.
① gas-tight insulation system (shell)
The gas-tight insulation system made of ceramic, glass or microcrystalline glass, gas-tight insulation cylinder, dynamic end cover, fixed end cover, stainless steel bellows is a vacuum-tight container. In order to ensure the airtightness, in addition to the sealing type to have a strict operation process, but also requires the material itself permeability and internal outgassing is small.
②Conductive system
By the fixed conductive rod, fixed running arc surface, fixed contacts, dynamic contacts, dynamic running arc surface, dynamic conductive rod composition. Contact structure has three kinds: cylindrical contact, transverse magnetic contact with spiral groove running arc surface, longitudinal magnetic contact. At present, the longitudinal magnetic field technology is used, and this interrupter has a strong and stable arc opening capacity.

③Shield system
Shield is an indispensable component in the vacuum interrupter, and there are many kinds of shields around the contact such as main shield, bellows shield and shield for equal pressure. The role of the main shield is to: a prevent arc generation during the arc burning process spattering to the inner wall of the insulation shell, thus reducing the insulation strength of the shell. b improve the uniformity of the electric field distribution inside the interrupter, which is conducive to reducing the local field strength and promoting the miniaturization of the vacuum interrupter. c condensation of arc generation, absorbing part of the arc energy, which helps the recovery of the gap medium strength after the arc.
Operating mechanism
According to the different types of circuit breakers, the operating mechanism used is different. Commonly used operating mechanisms are spring-operated mechanism, CD10 electromagnetic operating mechanism, CD17 electromagnetic operating mechanism, CT19 spring storage operating mechanism, CT8 spring storage operating mechanism.
Other parts
Base, insulation support, insulator, etc.