Abstract: An improved circuit breaker includes an inertial time delay mechanism that permits a self-powered trip unit to become fully operational before inputting into the trip unit a signal indicating a change in the state of the circuit breaker. The time delay mechanism includes an inertia member, a first spring, and a second spring, and is activated upon the rotation of a lay shaft of an operating mechanism of the circuit breaker. The first spring extends between the inertia member and a housing of the circuit breaker and biases the inertia member from an initial position toward a terminal position. The second spring extends between the lay shaft and the inertia member and biases the inertia member toward the initial position when the circuit breaker is in an OFF condition. The combined action of the first and second springs on the inertia member provides a time delay using a relatively small inertial mass.

Abstract: A linear actuator which includes a housing assembly, a shaft assembly disposed within the housing assembly, a plurality of flat magnets disposed within said housing about said shaft, and a structure to support the magnets. Because the magnets are flat magnets, the components that support the magnets may be machined with tolerances that virtually eliminate the air gap between the magnets and the support structures.