Abstract: A circuit breaker includes a cam assembly which holds the load blade in contact with the line strap during normal operation. The cam assembly includes a cam surface on a cam which can slide along the load blade and a bearing surface on the load blade. In normal operation, the cam is biased on the load blade so that the cam surface engages the bearing surface. The force applied by the cam surface to the bearing surface in normal operation is approximately parallel to the force applied by the load blade to the line strap, thus, the cam surface does not tend to slide along the bearing surface during normal operation. When a high overcurrent fault occurs, blow-open forces exerted between the load blade and the line strap cause the cam to pivot to a position where the cam surface no longer engages the bearing surface, allowing the load blade to swing free of the cam and break the contact between the load blade and the line strap.

Abstract: A circuit breaker having a shunting contact structure with low watts loss and high withstand level. The circuit breaker of the present invention comprises an upper contact arm having a first contact disposed thereon and a lower contact arm having second and third contacts thereon with the second contact mating with the first contact. A shunt terminal is provided between the upper contact arm and the lower contact arm. The shunt terminal includes a fourth contact which mates with the third contact on the lower contact arm. The circuit breaker of the current invention has a closed, open and current limiting position. When the circuit breaker is conducting nominal rated current, the first, second, third and fourth contacts remain closed. When the circuit breaker is under fault conditions which are circuit current conditions above the withstand level, the circuit breaker switches to a current limiting mode.

Abstract: The outside poles of a three pole circuit breaker are each provided with a blow open latch which includes a latch hook having an open slot forming jaws pivotally mounted on the contact arm. A torsion spring biases the jaws to a cocked position in which they are aligned for engagement with a fixed stop member toward which the contact arm rotates as it blows open in response to the magnetic repulsion forces generated by a short circuit. As the jaws engage the stop member, the latch hook is rotated to mechanically latch the latch hook on the stop member thereby preventing rebound and reclosing of the contacts. A leaf spring mounted on the crossbar holds the latch hook in mechanical engagement with the stop member. As the circuit breaker responds to the overcurrent condition and rotates the crossbar, the leaf spring disengages from the latch hook so that the torsion spring can rotate the latch hook back to the cocked position for disengagement from the stop member upon reclosing of the circuit breaker.

Abstract: A switch has at least one fixed and one moving contact located on a contact arm. The fixed contact is connected to a loop-shaped conductor segment, such that when current flows through the conductor segment, there is an electrodynamic magnetic force which acts on the contact arm. The force, above a specified current intensity, results in an opening movement of the contact arm. To open the moving contact more rapidly and in a simple manner the loop-shaped conductor segment is realized so that it is wound in a coil shape, and consists of at least two turns, and that the coil axis of the coil segment runs perpendicular to the longitudinal axis of the contact arm.

Abstract: An electric motor control apparatus includes an electrical current control apparatus which is operable to limit current to an electric motor. When the electric motor is a three-phase motor, three current limiting switch assemblies are provided in the electric current control apparatus. A single stack of laminations concentrates magnetic fields emanating from conductors in all three current limiting switch assemblies. Each of the current limiting switch assemblies includes two movable contacts which are mounted on contact arms. The contact arms are movable in slots in the stack of laminations. A first series of splitter plates is disposed in an array along a path of movement of the contact on the first movable contact arm and a second series of splitter plates is disposed along a path of movement of the contact on the second contact arm for each of the current limiting switch assemblies. A short circuit splitter plate conducts electrical current between the two series of splitter plates.

Abstract: The helical contact compression springs of a circuit breaker are preassembled in a contact clip for easier assembly of the circuit breaker. The bottom wall of an elongated trough formed by the clip is pierced by holes forming cylindrical protrusions extending into the trough. The clip is placed over the springs supported in a row in a fixture. A die head presses on the spring clip to compress all the springs and then simultaneously insert punches into the holes in the clip to expand the protrusions and secure the springs to the clip. The fixture includes a slide mounted on guides for movement between a loading position and an operating position under the die head. A support block is pivoted on the slide to present one of two sets of spring recesses for circuit breakers having different current ratings with the slide in the loading position.

Abstract: A circuit breaker contact arm (56) contains a straight elongate through-slot (112) that runs generally lengthwise of the contact arm and is closed at both lengthwise ends. Adjacent each slot, a respective side wall (106, 108) of a cross bar (58) contains a bent slot (114) having a knee (116). A respective cylindrical blow-open pin (118) passes through all three of these slots. A small helical coiled spring (120) occupies the contact arm through-slot and is compressed between the blow-open pin and the end of the contact arm slot that is proximate a cross bar/contact arm hinge pin (110). The spring is laterally confined by the adjacent side walls of the cross bar so as to remain in the contact arm slot about which the contact arm swings. The spring acts between the blow-open pin and the contact arm to bias the blow-open pin in a direction away from the cross bar/contact arm hinge axis.

Abstract: A remotely controllable circuit breaker device for interrupting current in a circuit path between a source and a load includes local and remote monitoring capabilities and a gear mechanism for reliable remote control of the interruption mechanism. The device includes a first contact and a second contact cooperatively arranged in the circuit path so as to provide current from the source to the load. At least one of the contacts is disposed on a contact carrier which is movable for interrupting the current provided to the load. The gear mechanism includes a motor with a rotatable shaft which responds to open and closed control signals generated from a remote location, and a gear, rotatably responsive to the rotatable shaft, for controlling the contact carrier so that the circuit path is interrupted and established, respectively. The gear mechanism controls the contact carrier using a coupling arrangement, which has a first part coupled to the contact carrier and a second part coupled to the gear.

Abstract: The helical contact compression springs of a circuit breaker are preassembled in a contact clip for easier assembly of the circuit breaker. The bottom wall of an elongated trough formed by the clip is pierced by holes forming cylindrical protrusions extending into the trough. The clip is placed over the springs supported in a row in a fixture. A die head presses on the spring clip to compress all the springs and then simultaneously insert punches into the holes in the clip to expand the protrusions and secure the springs to the clip. The fixture includes a slide mounted on guides for movement between a loading position and an operating position under the die head. A support block is pivoted on the slide to present one of two sets of spring recesses for circuit breakers having different current ratings with the slide in the loading position.

Abstract: A current-limiting apparatus for a circuit breaker which makes it possible to effectively protect an electric load element by quickly blocking an electric flow path when an excessive current flows due to a ground, shortage, etc. at an electric flow path and preventing a re-formation of an electric flow path after the electric flow path is blocked.

Abstract: An apparatus for retaining a movable contact in a circuit interrupter includes a movable element that is displaced by gas pressure within the interrupter housing resulting from arcs generated during initial displacement of the movable element. The movable element may be a spanner extending between two stationary contacts. The apparatus may be configured as a three phase interrupter in which a single carrier or retainer is common to three power phase sections, and is displaced by interruption of a current carrying path for any one power phase section. The retainer may include a retaining pin which extends through the movable element. The movable element is biased into a conducting position and a head of the retaining pin contacts the movable element to hold it in a non-conducting position following a trip event.

Abstract: A circuit breaker device for interrupting current in a circuit path between a source and a load. The device includes a first contact and a second contact cooperatively arranged in the circuit path so as to provide current from the source to the load. At least one of the contacts is disposed on a contact carrier which is movable for interrupting the current provided to the load. A contact status indication arrangement is provided for indicating the status of the contacts. The contact status indication arrangement includes a trip flag, a status insert, a clear plastic lens, a flag guide, and a status flag. The trip flag, status insert and status flag are viewable through the lens, which is disposed in an aperture in the circuit breaker housing. Only one status indicator is viewable through the lens at any one time, each indicating a different circuit breaker status.

Abstract: A circuit breaker device for interrupting current in a circuit path between a source and a load includes a first contact and a second contact cooperatively arranged in the circuit path so as to provide current from a source to a load. A trip mechanism assembly, which includes an armature, a bimetal and a yoke, is provided for interrupting the current. The armature includes an aperture in which a latch point is provided to engage a latching surface of a trip lever for latching the trip lever thereon. The amount of current that is required to cause the trip mechanism to interrupt the circuit path is determined by the amount of overlap between the latching surface and the latch point. This overlap is adjusted by bending a calibration plate by tightening a calibration screw which extends through an aperture in a circuit breaker housing and a slotted aperture in the calibration plate. A substantially square shaped nut secures the calibration screw tightly against the housing.

Abstract: The movable contact arms of a circuit breaker are latched in the blow open position to prevent rebound and possible restrike of the arc in response to the very high magnetic repulsion forces generated by a short circuit in the protected electrical system. Each movable contact arm is mounted on a secondary carrier coupled to a main carrier by a spring loaded cam mechanism which allows the movable contact arm to blow open before the main carrier is rotated to the open position by the spring driven circuit breaker operating mechanism. In one embodiment of the invention, the movable contact arm is latched in the blow open position by a latching detent in the cam surface of the cam mechanism. In a preferred embodiment, the secondary carrier is latched by a detent formed by a leaf spring cantilevered from a fixed support. Subsequent rotation of the main carrier by the operating mechanism releases the latch by rotating the secondary carrier clear of the detent formed by the leaf spring.

Abstract: A thick solid steel slot motor is disposed adjacent a movable conductor to apply a contact closing force on the conductor, augmenting the contact pressure spring, under steady state current conditions, and to reduce the force under high rate of current rise conditions to enhance dynamic separation of the movable conductor from a stationary conductor, reducing the strength requirement of the contact pressure spring.

Abstract: A circuit breaker includes a first section and a second section with independently operating pairs of contact assemblies in each respective section. In the first section, at least one of the contact assemblies is constructed and arranged to interrupt the current by moving from a normally closed position to a blown-open position and latching with the contact assemblies separated. The second section has a biasing extension spring for biasing the contact assemblies of the second section so as to permit interruption of the current in response to a blow-open force, which causes the contacts to separate only momentarily and then return to a normally closed position. The first and second pairs of contact assemblies separate substantially simultaneously in response to the blow-open force, and only the first section reacts to lower-level over-current conditions. In addition to the contact assemblies, the second section of the circuit breaker is designed to operate using only a spring which is "Z-axis" mountable.

Abstract: A switch includes a moving element having a traveling contact at one end thereof, and a repelling element having a repelling contact at one end thereof and extending substantially parallel to the moving element, and the repelling contact capable of making and breaking contact with the traveling contact, and the switch further comprising a conductor connecting the repelling element to the side of a power source system, and the conductor including a first conductor portion positioned within the limits of the traveling contact and said repelling contact when said moving element and the repelling element are opened so as to be connected to the side of the power source system, and a second conductor portion connecting the first conductor portion to the repelling element at an end on the side opposed to the repelling contact.

Abstract: A circuit breaker including a base having an operating mechanism mounted thereon, a line contact blade assembly coupled to the operating mechanism for movement between open and closed positions, and a load contact blade assembly pivotally supported by a terminal strap for movement between an open and closed position with respect to the line contact blade is disclosed herein. A load blade return spring is positioned to bias the load contact blade assembly into engagement with the line contact blade. Furthermore, a multi-force spring device is disposed to apply a first force to the load contact blade while the load contact blade is in the closed position and a second force to the load contact blade in the blow open position, wherein the first force is greater than the second force.

Abstract: The protective device for protecting against over currents in electric circuits includes at least one electrically conductive body and two electrodes which function to supply circuit current through the conductive body and which lie against the conductive body at corresponding positions either directly or through the medium of an intermediate part. An abutment pressure is applied to the electrode so that the electrodes are maintained in abutment at the corresponding positions of the conductive body. When the devices are subjected to high short circuiting currents, the current density in the deformed abutment surfaces of the conductive body will increase, thus increasing the resistance of the device.

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: An electric switch includes a plurality of moveable contacts and a plurality of stationary contacts which firmly contact with the moveable contacts in a normal closed position by a spring, such as a leaf spring or a compression spring. The electric switch further includes a locking member which is disposed between two adjacent moveable contacts. When a "fault" current passes through the moveable contacts and the stationary contacts, a repulsive force is caused at the contact tips such that it tends to open the contact between the moveable and stationary contacts. The "fault" current also causes adjacent moveable contacts to attract to each other thus has tendency to open the contact. The locking member which is disposed between the neighboring moveable contacts engages with the moveable contacts so as to maintain the contact between the moveable contacts and the stationary contacts. The locking member has two oblique surfaces, one on each side, to face to the moveable contacts.

Abstract: A circuit breaker with an insulation device is formed of a molded case having side walls to form a chamber, a stationary contact member situated in the chamber and fixed on the molded case, a moving contact member movably connected to the molded case, a U-shaped magnetic driving core attached to the stationary contact member and having a pair of arms projecting outwardly from the stationary contact member, and an insulation cover. The side walls has slots therein, and the arms are situated inside the slots so that the outer surfaces of the arms are covered by the side walls of the molded case. The insulation cover has arm-shaped and board-shaped parts and is attached onto the outer surface of the stationary contact member. The board-shaped part covers the outer surface of the stationary contact member except the contact point, and the arm-shaped parts covers the inner surfaces of the arms of the magnetic driving core so that the inner and outer surfaces of the magnetic driving core are completely covered.

Abstract: An integral electrical circuit controller apparatus selectively connects a load to a power source and includes an electrical contactor having contacts, a circuit breaker having separable contacts connected in series with the electrical contactor and a trip mechanism responsive to current flowing through the separable contacts for tripping the contacts open in response to predetermined current conditions, and a current throttle impedance for limiting short circuit current. The trip mechanism and the electrical contactor independently interrupt current flowing through the electrical contactor and the circuit breaker. The current throttle impedance limits short circuit current flowing through the electrical contactor and the circuit breaker until current is interrupted. The electrical contactor may include an overload relay. The current throttle may include a coiled conductor of nichrome or iron wire enclosed in a dielectric housing.

Abstract: A switch having at least one power switching pole includes a contact bridge cooperating with fixed contacts and adapted to be maneuvered either by mobile parts of a solenoid or by a tripping mechanism. The contact bridge is rotatable and the mobile parts of the solenoid operate the contact bridge through the intermediary of a transmission mechanism.

Abstract: The contact depression effected between the fixed and moveable contacts in a high ampere-rated circuit breaker is fixed after assembly of the current carrying components by the provision of a multi-dimensional contact carrier support bearing. The selection of the support bearing dimension fixes the height of the movable contact arm and the attached movable contact relative to the subjacent fixed contact. Control of the contact depression improves circuit interruption efficiency and extends the operating life of the circuit breaker contacts.

Abstract: A subframe is coaxially pivotally mounted with a movable frame of the operating mechanism of a molded case circuit breaker and is locked to the frame by a bell crank pawl which is pivotally mounted on the subframe. A leaf spring assembly rigidly attached to the subframe overlies the movable contact finger to engage the same in the circuit ON condition of the circuit breaker to provide desired contact force. The bell crank pawl is released upon an incrementally small amount of initial movement of the movable contact arm in response to blow-open magnetic repulsion forces to release the movable contact finger for pivotal opening movement relative to the movable frame of the circuit breaker operating mechanism.

Abstract: An improved circuit breaker with moving line and load contacts is disclosed herein. The circuit breaker includes an enclosure for the operational components thereof including a line contact arm and associated contact for each phase of the circuit breaker, and an operating mechanism supported within the enclosure to move the contact arm(s) between open and closed positions. The circuit breaker also includes a terminal for each phase pivotally supported within the enclosure, and a load contact arm and associated contact for each phase pivotally connected to the terminal. The contact arms are supported so the contacts are engaged when the line contact arms are in the closed positions. The pivoted load terminal(s) allow the use of multiple connector types with the terminal(s), and the pivoting connection between the load contact arm and associated terminal facilitates a reduction in circuit breaker size for a given rating.

Abstract: A multi-phase circuit breaker including novel crossbar for opening and closing the circuit breaker contact arms. The crossbar is a one-piece plastic component molded to include an operating arm, insulating barriers for separating the contact arms of each phase, and the cam surfaces which interact with the cam followers of the contact arms. The operating arm is linked to the operating mechanism of the circuit breaker so that operation of the mechanism will pivot the crossbar which pivots the contact arms between their open and closed positions.

Abstract: Each breaking module is formed by a parallelepipedic monoblock cartridge made of plastic material, housed in the corresponding compartment of the base plate, said cartridge housing at least a stationary contact, an arc extinguishing chamber, and a pair of connecting strips for connection to a terminal and to the trip module of the same pole. A mechanical actuation module constituted by the switching bar and mechanism assembly, is securedly united to the cover. The rotary trip bar is supported by clipping means, arranged on the bottom face of the cover. A plurality cf recesses and cutouts are arranged in the spacers of the base plate to act as first bearing surfaces respectively for the switching bar and trip bar when the first sub-assembly A composed of the base plate with the set of breaking modules and trip modules, is adjoined with the second sub-assembly B formed by the cover on which the mechanical actuation module, trip bar and latch are fitted.

Abstract: A multipole circuit breaker having a movable contact for each pole, the movable contact being biased by a spirally-wound spring including a feeler part which slides on a bearing surface of the movable contact to modify the application point of a pressure force P in a second active repulsion position, resulting in a decrease of the restoring torque before operation of the mechanism. The movable contact is forked-shaped and is articulated on an eccentric spindle parallel to the rotation axis of the bar. The spirally-wound spring is mounted to float in the recess of the bar, and comprises two helicoidal wire windings.

Abstract: A molded plastic current limiting circuit breaker includes an interrupter assembly that includes an over-molded magnet, arc stack, baffle stack, and a chamber liner in which a trip unit is described.

Abstract: A circuit breaker includes a first section and a second section with substantially independently operating pairs of contact assemblies in each respective section. In the first section, at least one of the contact assemblies is constructed and arranged to interrupt the current by moving from a normally closed position to a blown-open position and latching with the contact assemblies separated. The second section has a biasing extension spring for biasing the contact assemblies of the second section so as to permit interruption of the current in response to a blow-open force, which causes the contacts to separate only momentarily and then return to a normally closed position. The first and second pairs of contact assemblies separate substantially simultaneously in response to the blow-open force, and only the first section reacts to lower-level over-current conditions.

Abstract: A contact arrangement for a circuit breaker utilizes magnetic attraction between parallel conductors in the movable contacts to open the contacts during a short circuit, high current condition. An elongated, pivotable, main contact arm includes a movable main contact at a first end that engages a fixed main contact in a closed circuit position. An elongated, arcing contact arm, pivotable in the same plane as the main contact arm, includes a movable arcing contact at a first end that engages a fixed main contact in a closed circuit position. The contact arms are spring biased in the closed circuit position such that a gap is defined between the arms. An attractive electromagnetic force tends to keep the first end of the arcing contact arm in contact with the fixed arcing contact until after the main contact arm has lifted. A hinge assembly for the main contact arm and the arcing contact arm assists in opening the contacts during the high current condition.

Abstract: A mid terminal for a double break circuit breaker comprises first and second elongated conductive plates, where each of the plates have first and second ends. The second end of the first plate is longitudinally spaced from the first end of the second plate and the first end of the first plate is connected to the second end of the second plate by a lateral conductive plate. A first are runner is electron beam welded to the second end of the first plate, and a second are runner is electron beam welded to the first end of the second plate. The first and second arc runners are preferably made of steel. A first stationary contact is mounted on the first plate adjacent the first arc runner, and a second stationary contact is mounted on the second plate adjacent the second arc runner.

Abstract: A blow-off terminal includes a flat conductive tang, a flat conductive input section, and a flat conductive output section. The input section includes a pair of generally parallel U-shaped strips. Each of the pair of strips includes first and second end portions and a center portion bridging the first and second end portions. The first and second end portions and the center portion of each of the pair of strips are generally co-planar, and the tang and the output section are generally co-planar. The output section is elongated and includes first and second ends, the first end being disposed closer to the tang than the second end. The first end portions of the strips are connected perpendicular to opposite sides of the tang, and the second end portions are connected perpendicular to opposite sides of the second end of the output section. A stationary contact is mounted to the surface of the output section.

Abstract: A molded plastic current limiting circuit breaker includes an interrupter assembly that includes an over-molded magnet, arc stack, baffle stack, and a chamber liner in which a trip unit is described.

Abstract: Molded insulating shell halves are secured together around a blowout coil, stationary and movable contacts to pivotally trap an armature assembly therebetween. Windows are provided in the shell halves to ventilate the electromagnet coil during operation. The electromagnet is removable through the window without disassembly of the contactor. Contact and armature adjustment is accomplished through additional window openings. An arc chute having left and right-hand arc extinguishing chambers each sub-divided into upper and front chambers splits the arc into four series segments and increases the overall length of the arc significantly over similar prior art devices.

Abstract: An electric circuit-breaker of the magnetic arc extinction type includes a fixed contact member comprising two electrically insulative parts. An auxiliary part of the fixed contact member is connected to an auxiliary terminal and includes an arc deflector branch so disposed that when the contacts open the current flows in opposite directions in this branch and in the mobile contact member.

Abstract: A high current capacity blade for a circuit breaker, comprises a conductive blade body having front and rear sections connected to one another, where the rear section includes a surface attachment area for fastening a flexible connector of the circuit breaker thereto. A strain relief tang extending from the rear section of the blade body is used to engage the flexible connector so as to stabilize the fastening of the flexible connector to the surface attachment area. A broad conductive lateral section is connected to and extends laterally from the front section, and includes a blade tab for engaging a toggle spring of the circuit breaker. A broad moveable contact is mounted on the broad lateral section and is adapted to interface with a stationary contact of the circuit breaker. A pair of substantially parallel L-shaped blade legs are spaced from one another to permit the toggle spring to pass therebetween.

Abstract: A molded case circuit breaker movable contact arm electrically connects with the circuit breaker load terminal requiring only a small diameter auxiliary electrical braid conductor by pivotally arranging the contact arm within its support. The braid conductor is electrically connected with the movable contact arm and is contained within the contact arm support posts. The contact spring and the terminal screw retainer are formed from a single plate of spring steel. The contact arm support posts are capable of supporting movable contact arms of various thickness.

Abstract: A blade suspension assembly for a circuit breaker includes a first electrical contact, an elongated contact arm having a second electrical contact adjacent a first end of the contact arm, a compression spring, and an elongated lever. The second electrical contact is movable about a first pivot axis between a contacts-closed position and at least one contacts-open position with respect to the first electrical contact. The lever has a first end adjacent a second pivot axis, a second end supported by the compression spring, and a contoured support surface between the first and second ends which supports a second end of the contact arm. The compression spring exerts a force against the second end of the lever so that the contoured support surface biases the second end of the contact arm about the first pivot axis in the contacts-closed position during normal operation and in the contacts-open position in response to the contact arm moving to the contacts-open position.

Abstract: Assemblies for providing the contacts of a circuit breaker with a pivoting motion. Each assembly is adapted to electrically couple the contact to the base of the assembly which is connectable to a terminal of the circuit breaker. Each assembly includes an arm for supporting an electrical contact, a pivot pin for pivotally mounting the arm, a base for supporting the pivot pin, and means for urging the pivot pin into contact with contact surfaces of the base. The arm is pivotable about the longitudinal axis of the pivot pin, and the arm and pivot pin are arranged such that at least two contact locations occur between the arm and the pivot pin.

Abstract: An electrical power switching device employing a rotary disc driven by an actuation means whose position is selected by a control means where disc contacts engage and disengage stationary contacts where the stationary contacts are deflected away from the disc contacts by separation ramps thereby opening the current path and an arc plate is used on the disc to control arc energy. A pair of interrupter contacts are placed in series with the rotary disc contacts where abnormally high currents cause the interrupter contacts to separate and open the current path where slot motors and/or arc plates are used to dissipate the damaging electrical arcs as the contacts make and break.

Abstract: The movable contact arm of a circuit breaker is mounted on a pivot pin by a slot which extends generally transverse to the longitudinal arm of the contact arm, so that when the contacts are welded, initial motion of the circuit breaker operating mechanism to open the contacts is translated into pivoting of the contact arm about, and thereby breaking the weld. In a circuit breaker in which the contact arm is coupled to the operating mechanism through a cam mechanism which allows the contact arm to blow open in response to very high overcurrents, the slot extends generally longitudinally so that the cam mechanism translates initial movement of the operating mechanism into longitudinal movement of the contact arm to apply a shear force tending to break the weld.

Abstract: A molded case circuit breaker having current limiting capabilities optimized for relatively smaller frame sizes. More specifically, one aspect of the invention relates to a two-piece carrier assembly for carrying the main and arcing contact arms which allows the main and arcing contacts to be blown open during short circuit conditions. The two-piece carrier assembly includes an inner carrier and an outer carrier pivotally connected together. The contact arms are carried by the inner carrier. When sufficient magnetic repulsion forces are exerted on the contacts due to a short circuit condition, the inner carrier pivots relative to the outer carrier to allow the contact arms to blow open. In order to control the amount of force required for blow open, a compression spring loaded cam assembly is provided.

Abstract: A molded case circuit breaker modular line strap assembly allows three components to be selectively interconnected for the different circuit breaker ampere ratings. A single component being used with the lower ampere ratings with additional components being additively assembled to accommodate the increased ampacity requirements with the higher ampere ratings.

Abstract: A movable contact bridge of a molded case limiting circuit breaker is supported by a bar by a system of springs enabling opening with electrodynamic repulsion. The contact bridge cooperates with stationary contacts rigidly secured to current input conductors in the shape of half-loops. An anvil is adjoined to the rear of the stationary contacts to increase the closing impact effect of the contact bridge and prevent contact resistance dispersions. The anvil is made of ferromagnetic material increase the magnetic field for blowout of the arc to the extinguishing chambers.

Abstract: The contact bridge of a molded case circuit breaker is rotatably mounted in a bar by two springs arranged symmetrically from the rotation axis. Each spring is, on the one hand, anchored to the contact bridge, and, on the other hand, anchored to a rod housed in a notch of the bar. The same springs provide contact pressure and slowing-down of opening of the contact bridge at the end of repulsion travel by electrodynamic effect. The contact bridge bears on its edge cam surfaces which, at the end of opening travel, engage the anchoring rods to move them in the notches in the elongation direction of the tension springs. The energy of the contact bridge is thus taken up and stored in the springs causing slowing-down of the contact bridge. The profile of the cams can be chosen to enable reclosing of the contact bridge, this reclosing naturally being delayed by the slowing-down effect at the end of travel. The cam profile can also ensure latching of the contact bridge in the open position.

Abstract: A pivoting lower contact arm arrangement and a circuit breaker including the arrangement. The pivoting lower contact arm arrangement includes a pivoting lower contact arm and a biasing arrangement. The biasing arrangement maintains the contact arm in an operating position with a first force, and biases the arm from a blown-open position toward the operating position with a second force. The first force is greater than the second force to provide increased separating speed when the pivoting lower contact arm blows apart from a pivoting upper contact arm of the circuit breaker and moves from its operating position. The biasing arrangement also variously provides magnetic shielding and coupling between the pivoting lower contact arm and other current carrying components of the circuit breaker. The magnetic shielding enhances the blow-apart forces between the pivoting upper contact arm and the pivoting lower contact arm.

Abstract: A repulsion type circuit breaker movable contact device comprising a first movable contact, an opening/closing mechanism which drives the first movable contact for opening and closing, a second movable contact for contacting the first movable contact, the second movable contact being freely pivotable and adapted to receive an electromagnetic repulsion force from said first movable contact, and a contact spring comprising a twisted coil spring disposed with its twisting fulcrum displaced from the rotational pivot of the second movable contact, the contact spring urging the second movable contact into contact with the first movable contact, whereby upon flow of a predetermined mount of electric current through the first and second movable contacts, the electromagnetic repulsion force moves the second movable contact apart from the first movable contact.