Core Component: Vacuum Interrupter
Acting as the "heart" of the circuit breaker, this is a fully sealed, high-vacuum component. It maintains an internal vacuum level typically below 1.3 × 10⁻² Pa and utilizes the high dielectric strength of the vacuum medium to achieve rapid arc extinction.
Airtight Insulation System:Composed of a ceramic or glass housing, metal end caps, and a stainless steel bellows; it isolates the interior from the atmosphere to maintain the high vacuum while allowing the moving contact to perform linear reciprocating motion.
Conductive and Contact System:The moving and fixed contacts are made of copper-chromium alloy, balancing electrical conductivity with resistance to contact welding. They often feature a cup-shaped structure with a longitudinal magnetic field, enabling rapid dispersion of metal vapor and arc extinction at current zero-crossing.
Shielding System: A shielding cylinder surrounding the contacts absorbs metal vapor generated during arcing, preventing it from condensing on the inner wall of the insulating housing-which would degrade insulation performance-while also ensuring a uniform internal electric field distribution.
Power Core: Operating Mechanism
Serving as the power source for the circuit breaker, there are two mainstream types, both ensuring precise and reliable opening and closing operations.
Spring Operating Mechanism: Releases energy stored in springs to drive the linkage for opening and closing operations. The closing process simultaneously stores energy for the opening spring. It offers a mechanical lifespan of up to 10,000 operations and is a mature, widely applied technology.
Permanent Magnet Operating Mechanism: Uses high-performance permanent magnets to maintain the open or closed state and electromagnetic coils to control operation. It contains fewer than 40% of the parts found in spring mechanisms, offers a mechanical lifespan of up to 100,000 operations, and is essentially maintenance-free.
Insulation and Support System
Utilizes insulating cylinders, insulating pull rods, and pole assemblies made from cast epoxy resin or SMC (Sheet Molding Compound) insulating materials to form insulation barriers against ground and between phases. These components offer excellent arc resistance, weatherability, and mechanical strength, making them suitable for complex indoor operating environments. Mainstream "solid-sealed pole" designs encapsulate the entire interrupter within the insulating body, further enhancing insulation reliability and the degree of protection.