Abstract: A solid state trip circuit is disclosed which uses a shunt path saturable transformer comprised of a current transformer having a relatively high resistance shunt which serves to apply input voltage to the transformer primary winding. The larger the input current the higher the voltage drop across the shunt and the more quickly the transformer iron will become saturated. The saturation time during each half cycle then produces a measure of the current flow in the primary line. The output of the secondary winding of the transformer as well as a direct but resistive connection from the input circuit lines are applied to a solid state trip circuit which operates a circuit breaker trip latch. Energy for tripping at lower overload current is derived directly from the applied voltage from the line. At high overload conditions however, direct tripping occurs through energy derived from the transformer rather than directly from the line voltage.

Abstract: Both undervoltage and shunt trip auxiliary feature modules, adapted to be mounted side-by-side with one or more circuit breaker modules include an electromagnetic trip device having a trip actuator which is biased toward tripping position and is normally latched in a reset position. A lost motion connection interconnects the actuator with a trip member which is in direct driving engagement with the releasable latch for the automatic trip means of the circuit breaker so that when the actuator is released, movement thereof is transmitted through the trip member to the circuit breaker latch for tripping of the latter. Each auxiliary feature module also includes a reset member which acts to automatically reset the actuator after each tripping operation thereof. The reset member is in direct driving engagement with the cradle of the circuit breaker contact operating mechanism so that movement of the cradle towards its tripped position will operate the reset member in a direction to reset the actuator.

Abstract: A compact molded case circuit breaker having a high interrupting capacity is provided with an arc chute constructed of stacked metal plates notched to form a passage for the movable contact as it moves between open and closed circuit position. The stationary contact is at one end of the arc chute and the arc plate at the other end of the arc chute is provided with a tab that extends outside of the arc chute. In its fully open position, the movable contact is positioned so that at least half of it is outside the arc chute, adjacent the free end of the tab on the last contact plate, and slightly spaced therefrom. The movable contact, in the terminal portion of its movement toward full open circuit position, moves generally parallel to the tab of the last arc plate. This construction assures that all of the arc plates will become active almost instantaneously at the time the movable contact reaches the tab.

Abstract: In certain applications, such as solderless cable connectors, a set screw is used to provide the connection between two or more current conductors. The set screw should be tightened to no more than a predetermined tightening torque. This is automatically accomplished by providing a section along the length of the set screw that is weakened to a predetermined extent, which causes the screw to break at the section upon attainment of the predetermined tightening torque. Both portions of the separated screw include means for being engaged for tightening or loosening the screw.

Abstract: A single pole molded case circuit breaker having a spring powered trip free contact operating mechanism including an extendable toggle connected at one end to a releasable cradle and connected at the other end to a movable contact, a latch for holding the cradle in reset position, and an automatic trip means for operating the latch to release the cradle upon the occurrence of predetermined overload conditions, is provided with anti-rebound means which prevents the movable contact from moving toward closed circuit position except under the influence of the operating mechanism. The anti-rebound means includes engaging formations of the cradle and toggle which cooperate to block the toggle from being extended unless the cradle is in its reset position. As the cradle moves to trip position it engages the toggle to kick the contact arm toward open position.

Abstract: A unitized combination motor starter includes a unitized insulating base for an electromagnetic contactor section and a circuit breaker section having automatic trip means. The unitized base is part of a common insulating housing for the contactor and circuit breaker sections and circuit elements serially connecting these sections are disposed within the common housing.

Abstract: A molded case multi-pole circuit breaker is provided with a solid state trip unit constructed to automatically open the breaker responsive to predetermined fault current conditions by actuating a permanent magnet latch. The latch and main conductors of the circuit breaker are constructed and arranged so that at very high short circuit currents, even if the solid state circuitry malfunctions, flux generated directly by current flow in the main conductors will buck the permanent magnet flux sufficiently to actuate the magnetic latch directly.

Abstract: A molded case multi-pole circuit breaker is provided with a solid state trip unit constructed to automatically open the breaker responsive to predetermined fault current conditions by actuating a permanent magnet latch. The circuit breaker is also provided with a thermal-magnetic trip means that acts independently of the solid state trip unit to automatically open the breaker responsive to predetermined fault current conditions.

Abstract: An electric motor for driving a circuit breaker operating handle is connected to the latter by two sets of linkages. The first set of linkages includes a drive arm and a driven arm mounted on fixed spaced centers and interconnected by a cam means. The drive arm is pivoted by connection to the drive motor through gearing and a slip clutch, and mounts a roller entered into a cam slot formed in the driven arm. The second set of linkages consists of a drive link and a main link also mounted on fixed spaced centers with the main link having means for engaging and moving a circuit breaker operating handle. The drive and main links are connected by a roller-slot arrangement, with the roller being positively guided along an arcuate path formed about a center remote from the centers of the links and arms. Positive guidance of this connecting roller causes the effective lengths of the links to change in accordance with different positions of the circuit breaker handle.

Abstract: A removable and replaceable solid state trip unit assembly for automatically opening a molded case multi-pole circuit breaker, is constructed so as to be interchangeable with a thermal-magnetic trip unit assembly.

Abstract: A molded case multi-pole circuit breaker is provided with a solid state trip unit constructed to automatically open the breaker responsive to predetermined fault current conditions. In addition, a bimetal actuated device sensitive to air temperature within the breaker housing is provided for automatically opening the breaker when air temperature within the housing exceeds a predetermined level.

Abstract: A molded case circuit breaker having a spaced plate arc chute for each pole thereof, with each arc chute having a V-shaped mouth region at one end and having separable arcing contacts positioned at the mouth region and having a space defined opposite the mouth region and between a cover plate region and a terminal bus for obtaining access to terminal mounting bolts, is provided with at least one arc chute extension attached to a cover panel portion. Each arc chute extension consists of a plurality of spaced conductive plates and insulated means for rigidly positioning each of the plates in close planar alignment with a plate of the arc chute to present an increased length serpentine path for extinguishing an arc produced by the interruption of voltages and currents in excess of the original arc chute rating. Arc chute extensions are introduced as a single unit to increase the interruption rating of as many poles of the circuit breaker as is required.

Abstract: An electrical connector is constructed by inserting the end of a stranded cable into a loosely fitted sleeve having diametrically opposed apertures. Thereafter, the sleeve is crimped for securement thereof to the cable. The crimping tool is provided with a punch section that moves through the sleeve apertures and in so doing pierces the cable by spreading the strands thereof, thereby forming a through passage for insertion of a mounting bolt that will be received by a threaded aperture in a terminal. During the crimping operation the sleeve is formed with an extensive flat surface area that will be in intimate contact with the terminal.

Abstract: A rotary handle operator mechanism is fixedly mounted in an enclosure having a circuit interrupter mounted therein on the rear wall thereof. The mechanism includes a main handle disposed outside the enclosure for manual operation and being keyed to a cam unit engaged with the circuit breaker handle. A latch unit, including a cover latch section, is provided with a notch formation and a cam formation that cooperate with a forwardly extending pin of the cam unit to provide a switch interlock and a cover latch release.

Abstract: A rotary handle mechanism for operating a switch device secured to the rear wall of an enclosure is mounted separate from the enclosure cover and extends through a cover opening to be operable from outside of the enclosure when the cover is closed. The mechanism is designed so that the elements thereof may be assembled selectively for operation within an enclosure having a cover that is hinged along one or the other of its edges.

Abstract: A circuit breaker module and a detector module are mounted side by side to form a ground fault interrupter. The detector module includes an electromagnet for mechanical engagement with operation of the automatic trip device of the circuit breaker to open the latter upon the occurrence of predetermined ground fault conditions. An indicator member is pivotally mounted between the detector and circuit breaker modules. When the electromagnet is energized, it moves the indicator member from a retracted to an indicating position. In the latter position a portion of the indicator member is readily visible to indicate that tripping has resulted from a ground fault rather than from an overload.

Abstract: In certain applications, such as solderless cable connectors, a set screw is used to provide the connection between two or more current conductors. The set screw should be tightened to no more than a predetermined tightening torque. This is automatically accomplished by providing a section along the length of the set screw that is weakened to a predetermined extent, which causes the screw to break at the section upon attainment of the predetermined tightening torque. Both portions of the separated screw include means for being engaged for tightening or loosening the screw.

Abstract: A fused GFI unit for manually controlling the application of electrical power to a utilization device while automatically protecting the device and personnel associated therewith from electrical hazards, includes a switch plate unit have an insulated handle for controlling mechanical current interrupting means. Fuse receptacle means is provided in series connection with the switch pole to protect the GFI unit and the power lines against overcurrent hazards. A ground fault detector operates an actuating member in mechanical cooperation with the latched portion of the switch mechanism to enable current interruption by the switch pole in the event an unbalanced current flow is produced in one of a pair of power lines by a personnel hazard. A compact sectionalized structure encasing the switch, the fuse receptacle means and the GFI detector results.

Abstract: A circuit protective arrangement which utilizes a circuit breaker, current limiting fuse and ground fault interruption means in a closely coordinated operation to achieve reliable current interruption in the event that an overcurrent or ground fault hazard occurs. The source voltage is above the voltage rating of both the circuit breaker and current limiting fuse devices and the available current from the source is in excess of the rated current interruption rating of the circuit breaker. A compact sectionalized or modular structure for replacement of an existing circuit breaker is shown.

Abstract: A plurality of single pole circuit breakers stacked side-by-side are interconnected by a tie rod connecting the magnetic armatures of their respective instantaneous trip means. When one pole is caused to trip because of a fault condition, a driving formation on the releasable cradle of the faulted pole delivers a hammerlike blow to a cam means on the magnetic armature. The energy imparted to the armature by this blow causes the latch carried thereby to move in the tripping direction substantially beyond the point required for releasing the cradle latch in the faulted phase. This added movement assures that the tie rod shall transmit sufficient motion to all non-faulted poles to cause tripping thereof.