Vacuum circuit breaker consists of three parts: the vacuum interrupters, magnetic or spring operating mechanism, brackets and other parts.
According to switch type of different external shield-ceramic vacuum interrupter, miniaturization of sealing Cup-type axial magnetic field vacuum interrupters, sealed in glass bubble interrupters, its basic structure is as follows:
① air-tight insulation system (shell)
Made of ceramic, glass or air-tight insulation made of glass-ceramic cylinders, end caps, fixed cover panels, stainless steel bellows air-tight insulation system is made up of a vacuum sealed container. In order to ensure air tightness, in addition to strict operation in sealing technology, also requested material permeability, and internal volume small.
② conductive system
By conducting rod, run ARC, constant contact, the moving contact, dynamic run ARC, conductive pole. Contact structure there are basically three types: cylindrical contact, with spiral grooves running ARC surface magnetic contact, the axial magnetic field contact. Currently using longitudinal magnetic field technology, this interrupter has a strong and stable electric arc, breaking capacity.
③ shielding system
Shielding is the indispensable element in vacuum interrupters, and around the contact of the main shield, corrugated pipe shield and shield and so on. Shield's role is: a to prevent arcing process of arc spray insulation within the wall of the shell, thus reduce the dielectric strength of the shell. B improve the arc indoor electric field distribution uniformity, helps to reduce the local electric field, miniaturization of vacuum interrupter. C condensation of arc, absorb part of arc energy, help to back-arc gap dielectric strength recovery.