| 摘要 |
A circuit breaker includes a fixable contact unit , a movable contact unit opposing the fixable contact unit, a switch unit actuating the movable contact unit and a trip unit blocking a main circuit through the swtich unit when an abnormal current occurs. The trip unit includes an instant dial and an instant spring, the instant dial including a magnet, an armature opposing the magnet, a temporary adjustment unit, an instant bar actuating the temporary adjustment unit and a cam being in contact with the instant bar and the instant spring connecting one side of the temporary adjustment unit and one side of the armature. The cam includes a plurality of local depressions, each corresponding to an instantaneous value and adjusts a moment arm length between the instant spring and the armature through the plurality of the local depressions. Therefore, the circuit breaker may adjust an instantaneous current as a predetermined percent of a rated current through a simple operation of an instant dial and the instantaneous current being a main circuit blocking current when an abnormal current occurs in a circuit breaker, may adjust a moment arm length between an instant spring and an armature through a plurality of local depressions, each corresponding to instantaneous value of an instant dial and adjusting an instantaneous current where a trip occurs as a wide percent range of a rated current and may detect an abnormal current when an abnormal current occurs in a circuit breaker to automatically actuate a switch and to block a main circuit for main circuit protection. |
