Abstract: A circuit breaker contact operating structure characterized by a circuit breaker operating mechanism having separable contacts of which one is mounted on a contact carrying arm. The arm being mounted on a one leg of a U-shaped flexible conductor. A guide link is pivotally mounted and connected to the arm to maintain the contacts in alignment during their separation. The operating mechanism having a latch for latching the arm in the closed-contact position of the arm and having a trip device for unlatching the latch in response to an overcurrent condition. The mechanism link is so placed on the contact arm structure as to effect a blow-on force on the contact structure during the duration of high overcurrent. At a preset current level, the mechanism link is prevented from applying the balancing force to the contact structure, thus allowing the blow-off forces due to the current in the contact structure to separate the contacts rapidly, and to effect current limitation and subsequent circuit interruption.

Abstract: A circuit breaker characterized by first and second main contacts and first and second arcing contacts. The first main and arcing contacts are mounted on a first contact carrying arm. The second arcing contacts are mounted on a second contact carrying arm. The second main contacts are mounted on a third contact arm. The first contact carrying arm is mounted on a first pivot and the second and third contact carrying arms are mounted on a second pivot. A spring for biasing the second main contact against the first main contact and in the closed position. A second spring for biasing the second arcing contact against the first arcing contact until after the first and second main contact separate.