Abstract: A circuit interrupter characterized by a movable contact on a contact-carrying arm movable between open and closed positions of a stationary contact mounted on one leg of a U-shaped conductor with another leg secured to the circuit breaker housing with a current throttling resistive element being disposed within the U-shaped conductive element for limiting the amount of fault let through current.

Abstract: A rotary handle operator for a circuit breaker with a linearly movable handle has a housing which is mounted over the circuit breaker handle. A slide carrying a rack engages the circuit breaker handle and is slidable within a chamber in the housing. The rack engages a pinion gear sector mounted on a rotatable shaft which extends through a cover on the housing. A rotating handle mounted on the shaft is rotated to linearly operate the circuit breaker handle or is positioned thereby when the circuit breaker trips. The handle may be locked in the off position by inserting the shackle of a lock through an aperture in a lever arm on the rotating handle to urge a pin on a spring biased locking piece within the handle lever into an aperture in the housing cover, or the shackles of several locks may engage a slot in a shroud surrounding the rotating handle to interfere with rotation of the handle out of the off position.

Abstract: A clip-connected terminal conductor uses a terminal lug for tightening together with a screw the line cable and the conductor end. A channel is provided in the lug for inserting therein, and guided by lateral wall of the channel, a spring-like member having centrally a boss which engages the aperture of the conductor end. The spring-like member has opposite ledges for clipping with the front and the rear edge of the base of the lug and channel.

Abstract: A circuit breaker has a magnetic trip assembly which can be adjusted to trip the breaker for low level overcurrents in the range of five to ten times rated current. The magnet trip includes for each pole of the breaker a helical torsion spring having one torsion arm which biases an armature against an adjusting bar to form a gap between the armature and a stationary magnetic structure in which magnetic flux strong enough to attract the armature and trip the breaker is induced by overcurrent. A second torsion arm of the spring has a first portion which bears against and slides along a pivot member carried by the adjusting bar to adjust the bias force applied to the armature by a given amount per unit travel of the adjusting bar over a low trip current portion of the range of travel of the adjusting bar.

Abstract: A trip interlock assembly trips a circuit breaker any time the circuit breaker is removed from its panel mounting. The trip assembly is adapted to be disposed about a load side terminal and cooperate with the circuit breaker tripping device. In one embodiment, the trip assembly includes a housing and a spring-loaded actuation arm, disposed generally perpendicular to the circuit panel surface. The actuation arm is formed with a cam surface which cooperates with a trip pin adapted to actuate said circuit breaker tripping device. The trip pin acts as a cam follower and rides along the cam surface formed in the actuation arm. When the actuation arm is in an inward position the trip pin is in a normal position. However, when the circuit breaker is removed from the panel, the actuation arm under the influence of a biasing spring moves outwardly. This causes the cam surface on the actuation arm to actuate the trip pin to trip the circuit breaker.

Abstract: A circuit breaker is disclosed having a movable magnetic core provided in the magnetic trip assembly thereof adapted to lower the current levels at which the magnetic trip mechanism will operate. The magnetic trip assembly also includes a pivotally connected armature, a current carrying conductor, a fixed magnetic yoke and a latchable operating mechanism. A primary air gap exists between the armature and the fixed yoke. The movable core is designed to move into an extended position which reduces the primary air gap which in turn increases magnetic flux coupling which allows the magnetic force required for the armature to pivotally rotate to unlatch the operating mechanism and thereby trip the circuit breaker to be generated at a lower current level. This reduction in current is the desired effect of the new design.

Abstract: A molded case circuit breaker includes a clear viewing window through its top cover to enable the position of its internally disposed separable electrical contacts to be externally visually discerned. A manually engagable handle extending through an opening formed in the top cover of the molded case of the circuit breaker has an electrically insulating strip or barrier secured thereto and movable therewith for covering the clear viewing window when the separable contacts are in their CLOSED position to prevent smoke and other arc products resulting from circuit breaker interruptions from obstructing the clear viewing window. The viewing window may be inserted in the top cover during the molding process or may be subsequently disposed in the top cover in the form of an insert fixedly secured thereto.