Abstract: A device is provided comprising a simple means for holding the contacts apart and insulated from each other after circuit breaking.A screen formed by an insulating plate of small thickness, is placed between two mobile contact levers and is urged by springs against flanges which are integral with the levers and which move apart when short circuit currents appear for allowing this screen to be rapidly projected between the contact inserts.This simple circuit-breaker device may be used such as it is or in association with a contactor for protecting lines which supply consumer apparatus.

Abstract: A circuit breaker having a pivotal movable contact arm (6) operated between open and closed positions with a stationary contact (14c) by an overcenter drive spring (8) in response to pivotal movement of a manual operating handle (4). A latch lever (10) is provided to locate the other end of the drive spring (8) and is releasable upon overload currents to carry the point of connection (10d) of the drive spring and latch lever essentially downward in line with the line of action of the drive spring to quickly reduce its force and stored energy, thereby quickly reducing the contact pressure provided thereby and enabling constriction and/or repulsion forces to separate the contacts (6c,14c). A further amount of movement of the latch lever (10) carries the point of connection (10d) of the drive spring and latch lever across the pivot plane of the movable contact arm (6) to separate the contacts. The latch lever (10) is released by a pivotally supported latch arm (12).

Abstract: A current-limiting electrical apparatus is provided including a housing with first and second electrical terminals contained therein. A pair of electrical contacts is disposed within the housing and electrically connected in series with the first and second terminals. A biasing means applies a biasing force to the pair of electrical contacts to bias them to a closed position. The pair of electrical contacts is configured to cause the contacts to electromagnetically repel each other and to overcome the biasing force and open when the current flowing through the contacts exceeds a predetermined value. A mechanism is provided responsive to the current flowing through the pair of electrical contacts for decreasing the biasing force as the current flowing in the electrical contacts approaches the predetermined value, to thereby decrease the predetermined value causing the electrical contacts to immediately open.

Abstract: An apparatus comprising a plurality of circuit breakers with a rigid contact bridge 16 cooperating with fixed contacts 9, 10 carried respectively by conductors 11, 12, generating repellent forces; the median region 21 of the bridge cooperates with a magnetic structure 37 providing the bridge with compensation forces for the contact pressure when the latter is under a predetermined threshold, above which the bridge is ejected from the fixed contacts. This contactor is advantageously used for the control of power consuming apparatus and protection of their supply lines.

Abstract: A narrow width, molded case circuit breaker having parallel, oppositely directed current paths in a conductive stationary contact support (8c) and a pivoting movable contact arm (12b) to cause separation of the contacts (10, 16) by repelling electromagnetic forces independently of a manual operating mechanism (6, 22) or a trip mechanism (18, 20, 22, 24, 26). An arc runner (8e) integral with the stationary contact support (8) has a slot communicating with a vent opening (2d) in the case for venting the arc gasses through the arc runner and vent opening. Arc plates (42, 44) are oriented parallel to the arc runner (8e) to reduce resistance to movement of the arc therethrough by means of gas pressure. Insulators (14, 52) are disposed over conductive members comprising the parallel current paths on the opposite side of the contacts from the arc runner to impede any tendency toward arc movement in an undesired direction.

Abstract: Current limiting circuit breaker having a plurality of movable parallel contact arms vigorously moved in the open circuit position by electrodynamic repulsive forces at the appearance of a short-circuit current. The opening movement of one of said contact arms is limited by an abutment and the movement of the other contact arms is limited by a lost motion mechanical linkage connecting together said contact arms so as to delay the reclosure and to prevent a reclosing before tripping of the circuit breaker.

Abstract: A circuit breaker with unitary actuating shaft characterized by a dielectric housing having separable housing sections for mounting opposed stationary contacts; a unitary, hollow actuating shaft for mounting movable contacts between open and closed positions with the opposed stationary contacts; and each section having an end wall with an aperture through which the shaft extends and is retained in alignment.

Abstract: An improved anti-rebound mechanism for circuit breakers having a blow-off, current-limiting feature is provided. The improvement consists of a ferromagnetic latch which is activated by any massive current surge through the circuit breaker sufficient to cause blow-off current interruption. The latch is caused to be magnetically attracted to, and engage with, a notch on a movable arm of a circuit breaker to maintain the arm in an open position until the circuit breaker is manually reset in a closed position.

Abstract: An electromagnetically operated electric switch combines the function of a contactor and a current-limiting circuit-breaker. The contact assembly of the switch includes two contact systems, which are different in function, with a fixed contact which is common to both systems. The first contact system is intended for normal operating current connections, whereas the other contact system is intended for breaking short-circuit currents. The contact-making elements in the two contact systems can be made of different contact materials, in order to obtain a long electrical and mechanical life.

Abstract: An electric switch, more particularly a current-limiter, to be actuated by a control pin which indicates the OFF or the ON condition, and which can be opened also by the agency of thermomagnetic tripping mechanisms and by means of a coil. A crank lever is linked to a swinging assembly which is rockably mounted about the pin and to a rocker carrying the rod to actuate the movable contacts. The lever, to be able to permit that the contacts may be closed, must rest on a step of another lever and this resting relationship can be undone either by acting upon the pin, or by means of the tripping mechanisms and the coil. The opening by means of the tripping mechanisms takes place with a kind of "stroke trip" action, the mechanism being automatically reset during opening. The action of the tripping mechanisms is visually displayed and the reclosure of such a switch can be caused dependent from a local intervention by means of a pushbutton.

Abstract: A circuit breaker having an arc suppressing means disposed adjacent a contactor section and including a first arc running plate extended from a fixed contactor and a second arc running plate opposed to the first arc running plate. The distance between the both arc running plates on the side close to the contactor section is minimized so as not to cause any spatial short-circuiting to occur. At portions of the both arc running plates defining the minimized distance, magnetic arc driving force motivated by mutually oppositely directed arc currents flowing through the respective arc running plates is increased to a large extent, whereby arc shifting to deion grid of the arc suppressing means can be performed effectively quickly.

Abstract: A rearward extension of a circuit breaker pivotally mounted movable contact arm is positioned, with the arm in its closed position, to engage a trip bar and trip the breaker in response to popping movement of the arm away from its closed position as induced by the flow of high level fault current. The trip bar is configured such that the circuit breaker is not tripped incident to manual operation of the movable arm between its open and closed positions.

Abstract: A molded housing contains a pair of cooperating contacts arranged to be magnetically blown open and an arc chute therefor. The contacts are biased closed and there is no mechanism for manually operating or latching open the contacts. The magnetically blown-open contacts are connected in series with respective poles of a conventional circuit interrupter which also has magnetically blown open contacts but which also has manual operating means and latch means for the contact system.

Abstract: The disclosed circuit interrupter comprises a magnetic core structure including a magnetic core and magnetic yokes defining an annular magnetic gap around the core, and a primary and a secondary coil wound on the core to form a current transformer. The movable contact arm is disposed in the magnetic gap to be magnetically driven to the open position, and a magnetic armature of an instantaneous trip means is disposed adjacent to the magnetic yokes so that it is magnetically actuated upon a short-circuit current. A bimetallic element of a thermally responsive trip means is electrically connected to the secondary coil of the transformer. The magnetic yokes include extended portions which serve as magnetic means for driving an electric arc established between the separated contacts into an arc extinguisher which is also disposed between the magnetic yokes.

Abstract: Current limiting switch for rapid circuit breaking, including at least one pair of contacts, one contact being mounted stationary and the other being mounted on a movable arm. The contact arm is rotatable about a fixed point upon surpassing a predetermined current threshold value, by means of an electromagnet energized by the current passing through the switch. The electromagnetic means comprise an electromagnet and a first and a second armature cooperating with the electromagnet, in which the first armature drives the movable contact in the direction of disengagement and the second armature releases a locking device, which blocks the movable contact in the direction of movement until the current threshold is reached.

Abstract: A fast opening contactor comprising an electrodynamic repulsion trip device associated to a standard contactor unit so as to operate the contacts towards the open position against the electromagnetic attraction force in response of a short-circuit current.

Abstract: The common trip mechanism of a multi-pole circuit breaker is supplemented by individual breaker pole trip mechanisms operating independently of each other in response to fault current flowing in its breaker pole to unlatch the movable contact arm operating therein for uninhibited, independent opening movement from its closed circuit position to a tripped open position motivated by the electrodynamic forces associated with its breaker pole fault current.

Abstract: A circuit breaker having stationary contactors provided for all of the poles thereof. Movable contactors are provided for all of the poles in correspondence to the stationary contactors. Stationary contacts are provided on the end portions of stationary contactors and movable contacts are disposed on the end portions of the movable contactors. The movable contactors are movable from the stationary contactors by electromagnetic force to open respective circuits before the circuit breaker is opened by an overcurrent tripping device when large current such as short-circuit current flows. Holders adapted to hold the movable contactors of all of the poles are mounted on a common rotatable insulating rod, one of the holders being provided with a latch which is turnable around a rod provided on the holder. A slot is normally engaged with the latch, and when disengaged from the latch, a rod can be turned by the holder.

Abstract: A miniature current limiting circuit breaker incorporates double break circuit interrupting contacts capable of being abruptly separated by a high fault current responsive solenoid acting to first trip the breaker mechanism and then forcibly effect contact separation. The arc chamber is constructed to achieve enhanced blowout of the arc into the arc chute and to develop gas pressures acting to accelerate contact separation. The circuit breaker is trip-free and includes both thermal tripping and internal common tripping capabilities.

Abstract: A current limiting circuit interrupter includes two parallel pivoting contact arms carrying contacts at the ends thereof. The upper contact arm is pivoted upon a carriage which is in turn pivotally mounted upon a mechanism frame. A latch rod is movably secured in arcuate slots in the sides of the mechanism frame. When the circuit interrupter is in the closed circuit position, a pair of springs connected between the latch rod and the carriage urges the latch rod against a reaction surface of the upper contact arm to provide contact closing pressure. Upon occurrence of severe overload current conditions, the upper contact arm pivots upon the carriage, moving the latch rod within the arcuate slots to release the contact closing pressure, allowing the springs to move the latch rod against a latching surface of the upper contact arm to latch the upper contact arm in the open circuit position.

Abstract: A unitized combination starter is constructed with circuit breaker and contactor sections, each of which is provided with a pair of spaced stationary contacts and a cooperating movable bridging contact. The bridging contacts are closely spaced, are parallel and carry currents which flow in opposite directions. Under severe fault conditions a strong blowoff effect is created to force both bridging contacts in their respective contact opening directions. This quickly places four air gaps in the current path to severely limit current rise and thereby facilitate circuit interruption.

Abstract: A circuit breaker including first and second spaced-apart stationary contacts and a movable contact operable between open and closed positions with respect to the stationary contact wherein the movable contact, when in the closed position, conducts electricity between the stationary contacts and wherein the movable contact, when in the open position, is spaced apart from one of the stationary contacts. The movable contact has a longitudinal slot extending from one end thereof, and the movable contact is pivotally engaged to one of the stationary contacts at the movable contact end wherein the slot is located. The first stationary contact has an end portion thereof which is disposed within the movable contact slot. Also included is a mechanism for effecting movement of the movable contact between the open and closed positions and magnetic repulsion members for increasing the contact pressure between the stationary and movable contacts.

Abstract: A molded case current limiting circuit interrupter includes a pair of pivoting contact arms each supporting a contact and being connected to wiring terminals such that current flows through the contact arms in opposite directions. One of the contact arms has a movable pivot point. A magnetic drive slot motor device is provided to generate electrodynamic contact opening force upon the contact arms during short circuit conditions. A high-speed magnetic trip device releases the operating mechanism under short circuit conditions to move the arm pivot point before the contact arms reclose. A spring latch may be provided to latch the upper contact arm in a contact-separated position during short circuit conditions until such time as the overcurrent flow through the breaker operates a thermal and magnetic trip mechanism to move an operating mechanism to the tripped position.

Abstract: A circuit interrupter includes two parallel pivoting contact arms, the lower of which is connected to a stationary conductor member using a clinch-type contact. The contact arm has an axle member rigidly attached thereto which is supported by a bearing member attached to the conductor. In one embodiment, the bearing member comprises a pair of bifurcated arms which are clamped about each end of the axle member. In an alternative embodiment, the conductor member lies generally parallel to the lower contact arm and is slotted to form a pair of elongated conductor arms, each of which supports a journal bearing member. One end of the axle is extended through each journal bearing.

Abstract: A circuit breaker including first and second spaced-apart stationary contacts and a movable contact operable between open and closed positions with respect to the stationary contact wherein the movable contact, when in the closed position, conducts electricity between the stationary contacts and wherein the movable contact, when in the open position, is spaced apart from one of the stationary contacts. The movable contact has a longitudinal slot extending from one end thereof, and the movable contact is pivotally engaged to one of the stationary contacts at the movable contact end wherein the slot is located. The first stationary contact has an end portion thereof which is disposed within the movable contact slot. Also included is a mechanism for effecting movement of the movable contact between the open and closed positions and magnetic repulsion and magnetic attraction elements for increasing the contact pressure between the stationary and movable contacts.

Abstract: A current limiting circuit breaker includes two parallel pivoting contact arms carrying contacts at the ends thereof. The upper arm is double pivoted and is operated by a mechanism between open and closed positions. A magnetic drive slot motor device surrounds the lower arm and operates during extreme overcurrent conditions to draw the lower arm down and aid in rapidly separating the contacts. An arm positioning assembly is spring loaded to bias the lower arm toward a closed circuit position and provide contact closing force, the upper limit of travel being set by a rod extending through the end of the lower contact arm to abut against the slot motor.

Abstract: A current limiting circuit interrupter comprises a molded case, separable contacts disposed in the case, the contact arms supporting one of the contacts, an operating mechanism connected to the contact arm to move the arm between open and closed positions, and a slotted magnetic drive device generating electrodynamic force on the contact arm during extreme overcurrent conditions to rapidly separate the contacts. The magnetic drive device includes a molded housing forming a slot having insulated walls disposed about the contact arm, and a stack of U-shaped laminations of magnetic material fitted into the housing. The space between opposing walls of the housing is slightly less than the thickness of the lamination stack so that the laminations may be snugly press-fitted into the housing. The housing is then secured to the case in such a manner that the laminations are captured and securely positioned without the need for rivets or other fastening means extending through the lamination stack.

Abstract: A circuit breaker having a magnetic device energized by the current flowing through the circuit breaker to drive a contact arm to an open position at high speed to provide current limiting upon occurrence of a predetermined overcurrent condition. The magnetic device comprises a saturable magnetic shunt path, the iron of which saturates above said predetermined overcurrent condition, to energize the magnetic device and to cause a straightforward opening of the contacts.

Abstract: A circuit interrupter with improved current withstand capability characterized by stationary and movable contact means, the stationary contact means comprising first and second conductors being substantially parallel and having an air gap therebetween, the first conductor being pivotally mounted on the second conductor and being in the zone of pivotal movement of the first conductor so that when a fault current of predetermined conditions occurs a magnetic flux between the first and second conductors urges the first conductor toward the movable contact means.

Abstract: A current limiting contactor characterized by stationary and movable contacts, an elongated conductor supporting the movable contact, the conductor being fixedly mounted at a position spaced from the movable contact, the conductor having a looped portion including a pair of overlapping segments for conducting current in opposite directions of each other, the movable contact engaging the stationary contact when conducting a current up to a predetermined current value, and the conductor being comprised of a flexible material and the overlapping portions being separable to move the movable contact away from the stationary contact when the current exceeds said predetermined value.

Abstract: A multi-pole circuit breaker includes a wide toggle shaft which spans all of the poles of the breaker and which is electrically neutral. The lower links of the toggle mechanism are made of phenolic or other insulating material which thus electrically insulates the wide toggle shaft spanning all of the poles of the breaker and makes the toggle shaft electrically neutral. A plurality of short toggle springs may therefore be connected between the wide toggle shaft and a handle arm of corresponding width. The plurality of short toggle springs provide as much tripping energy as the longer single or double toggle springs of prior art circuit breakers in which the springs are clustered together in alignment with one pole of the breaker to which they are electrically connected and whose polarity the toggle springs in such prior art breakers accordingly take.

Abstract: A multipole circuit breaker is constructed with a single rod pivotally mounting all of the movable contact arms to a common one piece molded insulating carrier. Individual torsion springs engage each of the contact arms to provide contact pressure when the circuit breaker is closed. The construction of the contact arms and carrier are such that under severe overcurrent conditions electrodynamic blowoff forces acting on the contact arms may bring about contact separation that is substantially as great as the contact separation that takes place when the circuit breaker is opened normally by its contact operating mechanism. An individual anti-rebound pin for each pole engages the contact arm of the associated pole to prevent rebound reclosing after electrodynamic opening. A camming means on the carrier releases the anti-rebound latches to permit manual closing of the contacts.

Abstract: A circuit breaker switch for periodic current has a stationary contact connected to a first current terminal; a movable contact connected to a second terminal and having a closed position in which it engages the stationary contact and an open position in which it is separated from the stationary contact, an actuating device for moving the movable contact; a locking device having an operative position in which it immobilizes the movable contact in its closed position and an inoperative position in which it is clear of the movable contact; and a current intensity-responsive device connected to the locking device for moving the locking device from its inoperative position to its locking position when the intensity of current flowing through the circuit breaker switch exceeds a first predetermined value and for moving the locking device from its locking position into its inoperative position when the intensity reaches a second predetermined value.

Abstract: A current limiting circuit breaker comprises an improved slot motor magnetic drive device. The threshold level of overload current which produces current limiting action is raised, yet the degree of current limiting action during high overload currents is maintained by placing a thin saturable magnetic steel plate across the open end of the slot motor magnetic drive device. During overcurrent conditions below the threshold value, the plate shunts most of the magnetic flux and prevents production of magnetodynamic force upon the contact arm. Above the threshold level, the overcurrent generates magnetic flux sufficient to saturate the plate and forces additional flux into the air gap where the flux interacts with the contact arm to drive the contact arm into the slot and produce current limiting action in a normal manner.

Abstract: A circuit breaker using magnetic latching force between a magnet element and an attracting magnet member and having a bias spring which normally applies a bias force to the magnet element establishing the magnetic latching force in the closing condition in a direction to separate the magnet element from the magnet member and it also acts to apply a contact pressure to a circuit breaker contact in the same closing condition.

Abstract: Current-limiting device having a movable contact vigorously moved in the open circuit position by an electromagnetic repulsion device at the appearance of a short-circuit current. A retarding member is mechanically linked to the movable contact to delay the reclosing of the contact and to prevent a reclosing before tripping of the circuit breaker.

Abstract: A multipole circuit breaker is constructed with a single rod pivotally mounting all of the movable contact arms to a common one piece molded insulating carrier. Individual torsion springs engage each of the contact arms to provide contact pressure when the circuit breaker is closed. The construction of the contact arms and carrier are such that under severe overcurrent conditions electrodynamic blowoff forces acting on the contact arms may bring about contact separation that is substantially as great as the contact separation that takes place when the circuit breaker is opened normally by its contact operating mechanism.

Abstract: A motor controller having a single set of contacts and two contact operating systems is provided for operation and protection of a motor and the associated circuitry over a complete range of possible currents. For a normal motor starter operation and for fault current up to a predetermined value, an electromagnetic actuator is used to open the contacts a relatively small distance such as 1/4 inch. For higher fault currents a magnetic drive or linear slot motor opens the contacts to a greater spacing such as 1 inch. The slot motor opens the contacts very rapidly giving rise to good current limiting. The disclosed integral motor starter utilizes a bridging contact arm on which are mounted a pair of movable contacts which are aligned to engage a pair of stationary contacts when the disclosed motor starter is closed, completing an electric circuit to the controlled motor.

Abstract: A circuit interrupter having a fixed elongated contact arm, with a fixed contact disposed at the end thereof, and an elongated movable contact arm, with a movable contact disposed at the end thereof, and a magnetic driving device for rapidly separating the contacts. The magnetic driving device is formed of a ferromagnetic material and has a slot formed therein which is magnetically open on one end. The fixed contact arm is partially disposed in the slot near the closed end and the movable contact arm is partially disposed within the slot towards the open end. The magnetic drive or slot motor rapidly separates the contacts upon a predetermined overload. Divergent arc rails lying in the same general plane extend from the fixed contact and the movable contact.

Abstract: A multipole molded case circuit breaker of moderately high rating is constructed of a stack of single pole units each having a contact operating mechanism and a trip unit. The movable contact arm is so positioned that it is subjected to magnetic blow-off effect, which even at relatively low fault levels, tend to open the contacts to enduce a current limiting action. A conducting strap within each pole unit housing is connected to the line terminal and is provided with a plurality of spaced connecting points each accessible through a different opening at the rear of the housing for connection to a panelboard bus bar.

Abstract: A current limiting circuit breaker having for each pole, a pair of main contacts separable upon operation of a thermally and electromagnetically operable tripping device and a pair of auxiliary contacts for current limiting in series with the main contacts and in parallel with a transformable resistor having a positive temperature coefficient of resistance. The auxiliary contacts are separable when an electromagnet is energized by a fault current which simultaneously energizes a field magnet to produce a transverse magnetic field across the auxiliary contacts and the arc formed between them when separating. This simultaneous action of electromagnet and field magnet coacting for rapid contact separation and lengthening of the arc upon flow of a fault current serves to increase arc voltage almost instantaneously to that of the source, about which time the fault current is totally shunted into the resistor.

Abstract: A circuit breaker includes a slotted magnetic device having a plurality of spaced slotted conductive plates and a moving contact arm positioned within the slot when the circuit breaker is in a closed circuit position so that current flowing through the contact arm has a component in a vertical direction with respect to the slot. An overcurrent condition through the circuit breaker causes magnetic flux to be generated within the slotted magnetic device which develops a force to drive the moving contact arm from the front to the rear of the slot in a direction generally parallel to the bottom of the slot, thereby actuating the circuit breaker from a closed circuit position to an open circuit position. The circuit breaker also includes an arc-extinguishing device including a plurality of apertured conductive plates. The moving contact arm includes a probe member extending into the apertures of the plates when the circuit breaker is in a closed circuit position.

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: High-current, current-limiting circit interrupter having arcing contacts connected in parallel with the main contacts. Impetus means open the main contacts strikingly to switch the short-circuit current to the high-resistance arcing circuit. Electrodynamic means cause the arcing contacts to remain closed a short lapse of time after the transfer of the short-circuit current to the arcing circuit. Further electrodynamic means cause the arcing contacts to open sequentially.

Abstract: A current limiter providing for a rapid triple series break in the protected circuit. Two movable contact arms are electromagnetically driven apart by two electromagnetic or slot motor drives for rapid circuit interruption when current through the current limiter exceeds a predetermined value. This provides twice the rate of contact separation than that which can be obtained from a single contact arm and consequently increases the rate of arc voltage rise and reduces peak let through current. The magnetic drive devices are formed from a ferromagnetic material and have a narrow slot formed therein, which is magnetically open on one end. Each contact arm is disposed in the slot of an associated magnetic drive device near the open end thereof. Each movable contact arm has a pair of spaced apart contacts mounted thereon. One of these contacts engages a stationary contact and the other contact engages a mating contact on the opposing movable contact arm when the current limiter is closed.

Abstract: This circuit breaker comprises closing-assist means for opposing the contact-repulsion forces developed when a high current flows through the circuit breaker. This closing-assist means comprises spaced segments of high permeability material fixed to opposite sides of the usual movable contact rod and projecting laterally therefrom. Two stationary bridging members of high permeability material are located at opposite sides of said contact rod, and each extends between said segments when the contacts are engaged. The segments are located in proximity to but slightly spaced from the bridging members when the contacts are engaged so that said bridging members and said segments define a high permeability path around the contact rod containing short gaps between said segments and said bridging members.

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: Circuit interrupter having a magnetic circuit energized by the current flowing through the interrupter and an induction plate that is movable with the movable contact of the interrupter. The abrupt rising of a fault current induces secondary currents in the induction plate which is located in the air gap of the magnetic circuit as long as the interrupter is in the closed-circuit position. The secondary currents tend to expel the induction plate from the air gap thereby moving the movable contact vigorously away from the magnetic circuit.

Abstract: A circuit interrupter characterized by a movable contact arm disposed between two spaced stationary contacts which arm is movable to the open position by electromagnetic forces generated by an overload current condition.

Abstract: A unitized combination motor starter is provided with a single insulated housing wherein a plurality of pole units are disposed side-by-side. Each pole unit includes a circuit breaker contact section and a contactor contact section. A spring powered mechanism for circuit breaker operation is disposed on one side of the pole units and an electromagnet for contactor operation is disposed on the other side of the pole units. The current carrying elements of each pole unit are arranged to provide a current loop having relatively close opposing arms so that large mechanical forces accompany high magnitude current flow. These forces are directed so as to produce a blow-off effect at the circuit breaker contacts, resulting in current limiting action to protect the contactor contacts.