Abstract: A combination motor-starter circuit breaker comprising a single set of separable contacts and providing the function of motor starting, circuit interruption, and current limiting. The combination employs three separate means for separating the contacts to provide these functions; a solenoid, an overcurrent trip mechanism, and a magnetic drive device for high overcurrent conditions. Arc rails and spaced conductive plates are provided to aid in extinguishing any arcs established. Movable contacts are mounted on a bridging contact arm which can be provided with two open positions, a first position for use during motor control wherein the contacts are separated by a relatively small distance and a second position for use during circuit interruption and current limiting.

Abstract: A motor controller providing a disconnect and a single set of movable contacts, to provide operation and protection of a motor and associated circuitry over a complete range of possible currents. Plug-in modules for a circuit disconnect, a solid state overload relay, and an instantaneous trip unit are provided. The disclosed integral modular motor controller consists of five major components: (1) an isolator switch, (2) arc chambers, (3) a linear slot motor drive, (4) a drive operator, and (5) a solid state control. For a normal motor starting operation and for fault currents up to a predetermined value, such as 1200 amperes, an electromagnetic actuator is used to open the contacts a relatively small distance such as 0.25 inch. For higher fault currents a drive or linear slot motor opens the contacts to a greater separation such as 1 inch.

Abstract: A latch for a circuit interrupter is provided wherein a movable member having a contact attached thereto is latched in a selected position by a spring member which is deflected by the movable member until a predetermined distance is exceeded at which time the spring member moves into a latching position with respect to a latching surface provided on the movable member. In its simplest form the latch uses a single piece of spring wire. As a movable member moves past, the spring wire moves aside and once the movable member has completely passed the wire, the wire springs back into place preventing the contacts from reclosing. A reset is provided which permits the contact arms to be closed by moving the spring member to one side. The disclosed latch is very fast acting, can be independently actuated for each phase, and can be positioned so as to not interfere with low current operation of the switching device on which it is employed.

Abstract: An improved low-voltage circuit-breaker, adaptable for both alternating-current and direct-current is provided having small contact separation, when opened, and a pair of adjoining arcing-rails arranged in generally-parallel relationship, and having only a small gap therebetween of the order of 1/4 inch or less. Preferably, at the ends of the parallel-arranged arcing-rails are a pair of diverging arc-horns, constituting integral extensions of the parallel-arranged arcing-rails, and resulting in considerable elongation of the established arc upon its movement onto the diverging portions of the arcing-rails.