Abstract: A molded case circuit breaker is taught with a housing base and a primary cover disposed on the housing base. The primary cover has a recess therein for an auxiliary module which is disposed in the recess. A secondary cover is disposed on the primary cover for covering the recess when the auxiliary module is disposed therein. In order to secure the auxiliary module underneath the secondary cover in the recess of the primary cover, the module has deposed thereon a locking protrusion which is complimentary with a locking opening in the primary cover. The locking protrusion is flexible and has a longitudinal central bulge so that as the protrusion is pressed inwardly into the opening, the bulge causes the flexible protrusion to reduce diameter due to the presents of longitudinal slots therein until the bulge has passed the opening in which case it springs outwardly toward its normal position thus securing the protrusion in the base.

Abstract: A circuit breaker includes a housing, an operating mechanism and separable main contacts, and a rotatable crossbar which rotates to open and close the contacts. The crossbar interacts by way of a protrusion thereon with a rotatable, positive off-link. A handle mechanism is disposed in the housing and has a handle protruding from the housing which is normally movable from a closed to open disposition. However, if the operating mechanism has reacted in such a way as to open the separable main contacts but, in fact, they have not opened because, for example, they are welded shut, the protrusion on the crossbar will interact with the positive off-link and prevent the handle mechanism from moving to the opened position thus warning personnel that the contacts have not opened.

Abstract: A motor operator unit for an electrical switch is pivotally mounted on a bracket to swing between a closed, operative position in which an actuator in the motor operator unit engages the switch handle for electrical operation of the switch handle and an open position in which the switch handle is freely accessible for direct manual operation. The compliant actuator which is translated by a motor driven threaded shaft overtravels at each end of its reciprocal path after actuation of the switch handle to toggle a single power switch which determines both direction and shutoff of motor operation. A lockout plate mechanically prevents electrical and manual operation of the switch handle and carries an interlock switch which only enables motor operation when the motor operator unit is in the operative position and not locked out.

Abstract: A circuit breaker has an electrically conductive blow open latch which forms part of the power circuit so that only short flexible shunts are needed between the latch and trip mechanism. Load current can be conducted from the contact arm to the electrically conductive latch solely through the interface between the latch and the blow open camming surface on the contact arm, and/or through additional short flexible shunts between the latch and the contact arm, preferably adjacent the pivot of the contact arm.

Abstract: A miniature ground fault circuit breaker having a housing assembled from molded sections has stiff conductors supporting the toroidal coils of the ground fault circuit in position in one molded section and aligning connectors secured to the stiff conductors for easier assembly of the molded housing sections.

Abstract: Apparatus is provided for an electrical circuit breaker for preventing the handle thereof from being moved to the OFF position when the electrical contacts of the circuit breaker are welded closed. This apparatus mechanically limits the travel of the operating handle so that it may not be moved to the OFF position when the electrical contacts are closed. This restrictor apparatus as it is called is mechanically connected to, but out of direct contact with the handle arm of the circuit breaker. The mechanical linkage between the operating handle and the contact arm of the circuit breaker includes a projection. During the foregoing condition, the projection will interact with a crossbar assembly for the contact arm of the circuit breaker.

Abstract: An electric operator having a reciprocally mounted actuator is adapted to be mechanically coupled to an operating handle from a molded case circuit breaker or a molded case switch for moving the operating handle between an open position or, alternatively, to a closed position. The electric operator includes an electric motor for driving the actuator and allowing the circuit breaker to be controlled from a remote location and a mechanical crank assembly which alternatively allows for manual operation of the actuator in the event of a loss of electric power to the electric motor.

Abstract: A crossbar assembly is formed from an elongated metal bar. A pair of contact arm carriers are slid onto the metal bar and welded in place. Molded electrically insulated sleeves are sliding received at each of the crossbar. The insulated sleeves can be either molded directly on the crossbar or molded separately, in which case, the sleeves are glued with epoxy and pinned to the crossbar to prevent axial movement of the sleeves with respect to the crossbar. The insulated sleeves are formed with a pair of plates disposed at each end. A pair of oppositely disposed slots formed in the plates is used to receive the ends of a cam roll pin assembly. Since the crossbar in accordance with the present invention does not require wrapping with insulating paper, the possibility of dielectric failure due to cracking of the insulating paper is eliminated.

Abstract: A laminated contact assembly formed from a plurality of contact arm subassemblies includes a contact arm portion, for carrying a movable main or arcing contact, and a stationary conductor portion. A flexible shunt, form wound from a flat electrical conductor, is used to connect the contact arm portion to the stationary conductor portion. The flexible shunt is formed into a V-shape defining two depending legs. The free ends of the shunt defining bulb portions are inserted into keyholes formed in the contact arm portion and the stationary conductor portion. A pin is inserted into a central portion of the bulb portion to exert radially outward forces against the interior surface of the keyhole to increase the contact force between the bulb portions and the keyholes to form joints having a lower electrical resistance. The pin may be inserted into the central portion of the bulb portion by orbital riveting.

Abstract: A molded case circuit breaker is provided with a quick change current transformer assembly. The current transformer is used to sense overcurrent conditions and apply a signal to an electronic trip unit to trip the circuit breaker. The quick change assembly includes an insulated removable plate located adjacent an open cavity in the housing in which the current transformer is located. The current transformer is donut-type disposed about a load-side conductor located in a cavity in the housing rigidly fastened to the circuit breaker frame. In order to replace a current transformer, the insulated backplate is removed. Next the load-side conductor is unfastened and removed from the circuit breaker housing. The current transformer is then removed from the circuit breaker housing. In order to install a new current transformer, the steps are reversed. A force transmitting spacer is disposed adjacent a bight portion of a shunt, connected between a pivotally mounted contact arm and a load-side conductor.

Abstract: Apparatus which is mechanically connected to and out of direct contact of the handle arm of an electrical circuit breaker to prevent the operating lever of the circuit breaker from being moved to the off position when the contacts of the circuit breaker are closed, due to a weldment of the contacts or obstruction of the contact arm carriers. In particular, a two part toggle mechanism is provided for opening and closing contacts in conjuction with the movement of the operating lever. The lower toggle link has a protrusion thereon which abuts against the rotatable crossbar mechanism which carries the contact arm of the moveable contacts if the contacts have not separated as the operating lever is moved from the closed to open position. The abutments, however, will rotate free of the crossbar if the contact arm moves in conjunction with the movement of the crossbar as the lever is moved from the open to closed position.

Abstract: A molded case circuit breaker is provided with a toggle assembly having upper toggle links secured to U-shaped members of a cradle assembly with a hardened pin. The pin is formed with annular grooves disposed intermediate the ends forming a center sleeve portion and stop surfaces at each end. The center sleeve portion is slightly longer than the width of the U-shaped member to provide spacing between the upper toggle links and the U-shaped members. The upper toggle links are formed with U-shaped slots disposed at one end which are received in the annular grooves. The U-shaped slots formed at the other end of the toggle links are offset from the longitudinal axis of the toggle links and receive the pin. The upper toggle links are assembled such the offset U-shaped grooves are disposed in opposite directions to help secure the the assembly together.

Abstract: A multipurpose combination barrier and auxiliary current transformer board is provided for a circuit breaker. The board is located at the rear of the circuit breaker housing to close an open portion of the housing and act as a barrier to prevent contact with internal circuit breaker components. Vent holes, provided in the bottom portion of the board, allow heat generated within the circuit breaker to be exhausted to the atmosphere. The top portion of the board serves as a mounting plate for the auxiliary current transformers. The top portion of the board is formed from a printed circuit board having an electric circuit disposed thereon for the connections between the main current transformers, auxiliary transformers and the electronic trip unit. Connectors are provided on the printed circuit board adjacent each auxiliary current transformer to connect the main current transformers to the printed circuit.

Abstract: A molded case circuit breaker is provided with rubber stop assemblies disposed between the contact assemblies adjacent the outside poles and the cover portion of the housing. The rubber stop assemblies are disposed such that they prevent the contact assemblies from damaging the cover. The stop assemblies include a dual purpose U-shaped bracket having two parallel sets of arms. One set of arms is provided with aligned apertures at the free ends for receiving a pin which defines a pivot point for the crossbar assembly. The other set of arms is also provided with aligned apertures at the free end for receiving a metal pin for carrying a cylindrical shock absorber assembly. The shock absorber assembly is mounted adjacent outside poles above the contact carrier but spaced away from the inside of the cover of the circuit breaker. Thus, when the contact arm is opened, it will stop against the shock absorber and not damage the circuit breaker cover.

Abstract: A cam roll pin assembly includes a cylindrical portion having an extending axle at each end for receiving a small roller and a relatively larger roller. The smaller roller is provided for engaging the cam surface on the contact assembly. The larger roller is received within a slot. Retaining rings are used to secure rollers on the axles. With such an arrangement the rollers are able to rotate independently. Thus, during a blow open condition, the contact points of the cam roll pin assembly can rotate in opposite directions without causing relatively large frictional forces on the cam roll pin which can slow down the blow open speed.

Abstract: A circuit breaker with a force generate shunt characterized by a circuit breaker structure between spaced conductors with a fixed contact on one conductor and a movable contact on a contact arm that is movable between open and closed positions. A flexible shunt connected between the arm and the other conductor which shunt includes folded-over shunt portions that generate repulsion magnetic forces for pressing the closed contacts together and for expediting the contact arm open.