Abstract: An improved circuit breaker includes an arc extinction system having one or more insulators that generates a desirable gas in the presence of an arc. The exemplary circuit breaker includes gas-generating insulators disposed at three sides of a stationary contact and an arc chute at a fourth side of the stationary contact. The gas promotes the desirable extinction of the arc in a number of exemplary fashions. The presence of the gas on three sides of the stationary contact can resist movement of the arc toward the gas, thereby substantially limiting movement of the arc in a direction other than toward the arc chute. The gas can remove heat from the arc, thereby promoting deionization of the plasma by forming neutral molecular species at a lower temperature state. The presence of the gas can reduce the concentration of ions and electrons within the interior of the circuit breaker and can increase the pressure within the circuit breaker, and these also facilitate extinction of the arc.

Abstract: An improved circuit breaker includes a case, a movable arm, and a bumper retained within a receptacle formed on the case. The bumper is retained in the receptacle by a number of spaced ribs that engage certain portions of the bumper yet permit deformations of other portions of the bumper into an expansion region. By employing a bumper made of a material having a low coefficient of restitution, deformation of the bumper tends to dissipate the energy of a removable arm impacting the bumper. The bumper can be installed, removed, and replaced substantially without requiring the use of an adhesive. The movable arm engages the bumper on a corner of the bumper to provide the bumper with an effectively progressive spring rate.

Abstract: A mounting bracket for a circuit breaker air-core coil includes a unitary body having a generally U-shaped body. The body has at least one retaining form structured to fit over a fastener head. When installed in a typical power air circuit breaker, the air-core coil disposed in the mounting bracket is located above the circuit breakers's load conductor fasteners. These fasteners, and therefore the air-core coil, are located outside of the space in the circuit breaker occupied by a current sensor.

Abstract: A mounting bracket for a circuit breaker air-core coil includes a unitary body having a generally U-shaped body. The body has at least one retaining form structured to fit over a fastener head. When installed in a typical power air circuit breaker, the air-core coil disposed in the mounting bracket is located above the circuit breaker's load conductor fasteners. These fasteners, and therefore the air-core coil, are located outside of the space in the circuit breaker occupied by a current sensor.