Abstract: A circuit breaker includes a compressive turning spring hung between a movable contact arm pivoted at an end to a handle rotatably mounted to a first reference position and a cradle pivotably mounted to a second reference position and disengageably locked to an abnormal current detection and trip mechanism. Under normal operation of the breaker, the turning spring exerts a contact pressure between movable and fixed contacts. Upon detection of an abnormal current, the turning spring is caused to turn so as to open the contacts. With this arrangement, the dispositions of constituent elements and their interlocking assembly can be simplified.

Abstract: A circuit interrupter includes an arc extinction assembly for magnetically driving or blowing out an arc formed between a stationary contact and a movable contact. The assembly comprises a pair of coaxial windings which are disposed in proximity to the contacts so that the internal lines of magnetic force generated by and passing inside of the windings can act directly on the arc for magnetically driving the arc in one direction. A magnetic flux diverting yoke is provided in association with the windings to diverse therethrough the external lines of magnetic force generated by and passing outside of the windings such that the arc and a portion of the movable contact arm carrying the same will not be under the influence of the external lines of magnetic force even when the contact separation proceeds to a stage where the arc is extended past the region which is totally under the influence of the internal lines of magnetic force.