CIRCUIT BREAKER HAVING ISOLATION FUNCTION, CONCERNED WITH PREVENTING OPERATION HANDLE'S MOVEMENT FROM ON POSITION TO OFF POSITION WHEN MAIN CIRCUIT CONTACT IS STUCK BY ABNORMAL CURRENT

摘要

PURPOSE: A circuit breaker having an isolation function is provided to prevent an operation handle's movement from an ON position to an OFF position when a main circuit contact is stuck by abnormal current. CONSTITUTION: A circuit breaker includes a fixed contact(4), a movable contact(5) supported by a rotary type contact holder, a switching device(8), an operation handle, and an over-current tripping device. The switching device is operated by the operational handle in order to turn on or off a main circuit contact. The switching device includes a handle lever(11) coupled to the operational handle, a toggle link device(12) including a top toggle link and a bottom toggle link(12b), a tightly stretched spring installed between the handle lever and an arm connection point of the toggle link device, and a side plate(17) for supporting each component. The circuit breaker further includes a device having the first stopper and the second stopper in order to prevent the operation handle's movement from an ON position to an OFF position when the main circuit contact is stuck.