Working Principle of Vacuum Circuit Breakers
Body:
The core principle of a vacuum circuit breaker is to use vacuum as the arc-quenching and insulating medium. After the contacts separate, the arc is quickly extinguished to interrupt the current.
Working Process:
Closed state: Moving and fixed contacts are in tight contact; current flows normally through the contacts; no arc in vacuum.
Opening starts: The operating mechanism drives the moving contact rapidly away from the fixed contact; the contact gap increases quickly.
Vacuum arc generation: When contacts just separate, current cannot instantly become zero, so an arc forms between the contacts.
Arc extinction at current zero: For AC, each cycle passes through a current zero. At current zero, metal vapor condenses quickly, charged particles decrease rapidly, and the arc extinguishes.
Rapid insulation recovery: The dielectric recovery speed in vacuum is very fast; electric field strength recovers quickly, and high insulation strength is restored between contacts to prevent arc re-ignition and interrupt the current.
Advantages: Strong arc-quenching capability, good interrupting performance. Relatively simple structure, long service life. Low maintenance, reliable operation. Oil-free design eliminates fire and explosion risks.
CNYIHU manufactures vacuum circuit breakers and related power equipment. Our products undergo routine power frequency withstand tests, lightning impulse tests, and partial discharge tests to ensure reliable performance.
