CIRCUIT BREAKER

摘要

PROBLEM TO BE SOLVED: To provide a circuit breaker which can be manufactured inexpensively and its current contact can be protected from injury due to arc. SOLUTION: The circuit breaker is equipped with an arc extinction chamber 2 filled with a sulfur hexafluoride gas and extended to the longitudinal axis 3. The arc extinction chamber 2 is operated by a drive rod 4 which moves a central contact pin 14 and a rated current contact 11. The drive rod 4 is arranged so that the contact pin 14 stays at a first dead center at the beginning of the cutoff process. Thereafter, the contact pin 14 can move in the cutoff direction at a middle speed faster than that of the rated current contact 11. The contact pin 14 can reach the cutoff point after the rated current contact 11 completes its cutoff motion. While the connection arc is early ignited at the beginning of the connection process, the rated current contact 11 stays at a second dead center and therefore is protected from the damage due to arc.