Abstract: In a circuit breaker includes a fixed contactor, a moving contactor subjected to a switching operation of a switching mechanism, a heater connected to the moving contactor and disposed in such a manner as to extend along a fixed core and a moving core pivotally supported by the fixed core, the fixed contactor is formed in a J-shape and is interposed between an insulating member disposed on the fixed contactor in such a manner as to extend along the side of the fixed contactor facing the moving contactor and a demagnetizing member disposed in such a manner as to extend along the bent inner surface. The circuit breaker includes also an operation time adjusting mechanism engaging with the moving core and capable of adjusting the operation time of the moving core, and a casing storing therein the constituent elements. The operation time adjusting mechanism is brought into abutment against an adjustment portion formed on the moving core, and is detachably mounted on the casing.

Abstract: A circuit interrupter comprises a contact arm assembly for supporting the movable contact composed of a first contact arm and a second contact arm pivotally supported by a common pin, the first contact arm having an elongated guide hole extending in the direction of movement of the movable contact, the second contact arm having an elongated hole extending substantially in the direction of extension of the second contact arm. A second pin extends through the elongated hole and the guide hole, and a spring is provided for biasing the second pin. The elongated hole has a pin sliding surface on which the second pin slides and which forms an angle of 90.degree. or more with respect to a pin sliding surface of the elongated pin guide hole when the first contact arm is being reset after the second contact arm is separated by an electromagnetic repulsive force.

Abstract: A molded case circuit breaker crossbar assembly allows the movable contact carrier, contact spring and contact carrier operating cam to be preassembled prior to insertion within the circuit breaker case. The crossbar is fabricated from a plastic molding composition having means thereon for supporting the movable contact carrier and for retaining the charged contact operating spring. The contact carrier operating cam engages a roller carried by the operating mechanism link to couple the crossbar assembly to the circuit breaker operating mechanism.

Abstract: A bridging contact is arranged across two fixed contacts with a pair of parallel, closely spaced conductors serving as the bridging contact carrier. The conductors each form a pair of upper and lower links joined by means of a toggle pivot pin and are refrained from movement by means of a pair of tension springs. A high current pulse in opposite direction within the parallel conductors generates electromagnetic forces which propels the conductors apart. The bridging contact carried by the parallel conductors is thereby rapidly driven out of contact relation with the fixed contacts to interrupt the circuit.

Abstract: An integral circuit interrupter characterized by an assemblage of interconnected electrical units including a circuit breaker, a thermal-magnetic overcurrent detector, an electromagnetic actuator, and a modular sensor; the circuit breaker comprising first and second separable contacts and a releasable lever for releasing the first contact to an open position when the detector trips the lever in response to a first predetermined current condition; the electromagnetic actuator for moving the second contact to an open position; the modular sensor for monitoring current flow and for actuating only the electromagnetic actuator in response to a second predetermined current condition; and the electromagnetic actuator being operable from a remotely controlled source.

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.

Abstract: A high speed contact driver for use in an electrical circuit interrupter includes a pair of series-connected, elongate and generally opposing electrical conductors bowed in predetermined, generally opposing contours. These conductors are connected to a bridging electrical contact which is normally biased into a bridging position between a pair of stationary contacts. Pulse generating means are provided for applying a current pulse of predetermined magnitude to the electrical conductors. In response to this current pulse, these electrical conductors electromagnetically repulse each other and drive the bridging contact out of bridging position between the stationary contacts.

Abstract: A reverse loop circuit breaker characterized by a movable contact mounted on a contact-carrying arm movable between open and closed positions of a stationary contact that is mounted on one leg of a U-shaped conductor with another leg secured to the circuit breaker housing, an insulating block between the legs and including a pair of separable block portions having oppositely facing grooves for receiving edge portions of at least one leg to restrain its deflection, and means for securing the block portions together.

Abstract: A circuit breaker characterized by a movable contact on a contact-carrying arm movable between open and closed positions of a stationary contact mounted on one leg of a U-shaped conductor with another leg secured to the circuit breaker housing, a U-shaped brace between the legs and having a first support supporting and insulated from the other leg and having second supports on opposite sides of the one leg for retaining it against opposing repulsion magnetic forces due to current overloads.

Abstract: A contact assembly is provided for current-limiting low-voltage circuit breakers. The contact assembly has a two-armed contact lever swivel-mounted on a central bearing pin whose lever arms are equipped at their ends with contact pieces. The contact lever is equipped with a slot for mounting on the bearing pin whose longitudinal axis extends approximately at a right angle to the longitudinal axis of contact lever. The contact lever has a stop extending at approximately a right angle to its longitudinal axis for a catch swivel-mounted on the bearing pin. The contact forces on both lever arms cannot be influenced by the swivel mount or by the drive mechanism of the contact lever, but are determined exclusively by the biasing springs.

Abstract: A bridging contact is arranged across two fixed contacts with a pair of parallel, closely spaced conductors serving as the bridging contact carrier. A high current pulse in opposite direction within the parallel conductors generates electrodynamic forces rapidly propelling the conductors further apart. The bridging contact carried by the parallel conductors is rapidly driven out of contact relation with the fixed contacts to interrupt the circuit.

Abstract: A bridging contact is arranged across two fixed contacts with a pair of parallel, closely spaced conductors serving as the bridging contact carrier. A high current pulse in opposite direction within the parallel conductors generates electrodynamic forces rapidly propelling the conductors further apart. The bridging contact carried by the parallel conductors is rapidly driven out of contact relation with the fixed contacts to interrupt the circuit.

Abstract: A current limiting type circuit breaker includes first and second contact arms each pivotally mounted so as to be driven to an open position by an electromagnetic repulsive force, a trip device responsive to an output from a means for detecting a fault to drive the second contact arm to the open position, magnetic substances placed at opposite sides of the contact arms so that the magnetic resistance for magnetic fluxes occurred around the contact arms is decreased, and an attracting stationary conductor placed near the free end of the second contact arm in the open position. The attracting stationary conductor is connected in series with the first contact arm. When an excessive current flows through the contact arms, an electromagnetic attractive force is generated between the attracting stationary conductor and the second contact arm, which force increases the rate at which the second contact arm is moved to the open position.

Abstract: A contact assembly for electrical circuit breakers has a contact lever and a lever support with the contact lever mounted thereon in an articulate fashion. The support lever is flexibly positioned around a fixed pivot bearing by a drive linkage device for on- and off-switching cycles. A pressure lever is used to introduce a current-dependent force onto the contact levers in order to increase the contact force. The pressure lever is similarly flexibly mounted onto the lever support. The contact lever and the pressure lever operate jointly via their working surfaces which permit a conveyance of force in terms of an increase of the contact force. When switching on the contact assembly, the pressure lever is decoupled from the contact lever so that the tendency to bounce is reduced.

Abstract: The electromagnetic forces tending to force open the contacts of an electromagnetic contactor are reduced by providing a current flow path having a geometry that tends to minimize the magnetically produced forces acting upon the movable contact of an electromagnetic contactor. A contactor has a frame, a stationary contact attached to the frame, a first conductor supplying the stationary contact, an armature rotatably mounted in the frame, a movable contact attached to the armature, and a second conductor supplying the movable contact. An arm has a first arm end supporting the movable contact and a second arm end attached to the armature.

Abstract: Individual movable contactors of a circuit breaker are made up of a pair of conductors. The first conductor has one end bifurcated to form a pair of legs separated by a slit. At the open end each leg has a curved inner portion the opposed curved portions of the two legs defining a receptor space which is substantially circular in cross section. The second conductor has one end whose cross section is substantially circular and which fits within the receptor space and makes a good slidable contact therewith, and the other end which supports the main contact. Provision is made for rotating the second conductor about its circular end for opening or closing connection to the main contact.

Abstract: A stationary contact assembly is provided for a current limiting circuit breaker. The contact assembly includes a curved input arm which has a contact fastened thereon and a generally straight output arm which also has a contact fastened thereon and which has an opening for receiving the contact end of the input arm. The contacts are encapsulated in an insulating material which separates the contact arms from each other. A magnetic element is also embedded in the encapsulation material between the input and output contact arms. As current flows through the contact arms, a field is developed about the magnetic element which draws in an armature which reduces the opening force of the contacts.

Abstract: The gap distance separating the contacts of a low-voltage circuit breaker in the tripped position is increased by utilizing resilient stop means which is located at the bottom wall of the breaker housing rather than at the top wall (or on the handle of the breaker) in accordance with prior art practice. The movable contact arm is pivotally mounted and structured to strike the stop means as the contacts are separated and being blown open during short circuit conditions and, after the circuit breaker is tripped, the collapsed toggle assembly of the operating mechanism shifts the movable contact arm away from the stop means and allows the arm to move an additional distance away from the fixed contact and thus increase the gap distance between the opened contacts.

Abstract: A circuit breaker contact configuration reduces the occurrence of contact bounce by providing a reverse force to the contacts during contact closure. This reduces the contact closing shock energy, while keeping the contact bias force constant. In one embodiment, the reverse force is obtained by means of a counteracting spring which engages one of the contact arms at a point along the rebound path. Another embodiment comprises transferring the pivot point of one of the contacts from a first to a second position at a point along the rebound path.

Abstract: A movable contact arm assembly is provided for a circuit breaker. The contact assembly includes a carrier which has first and second guide plates with aligned roller guides and bracket supports and a roller which has a middle portion extending between the guide plates and the end portions and engaging the roller guides. A bracket extends between the guide plates and engages the bracket supports. A spring is positioned between the bracket and roller which urges the roller along the roller guide. The contact arm has first and second cam surfaces and is positioned between the guide plates and pivotally connected thereto. The roller rides in the guide on the first and second cam surfaces and the roller moves from the first cam surface to the second cam surface as the contact arm moves from a closed position to an open position in response to preselected electromagnetic repulsion forces.

Abstract: A circuit breaker with blow open contacts is provided with a housing. Each pole of the circuit breaker has a reinforced molded housing. The walls of the housing are provided with reinforcing ribs to withstand the high pressures caused by gases generated by the arc during interruption of high short circuit currents.

Abstract: A blow open contact arm assembly is provided for a molded case circuit breaker. A ferromagnetic carrier is attached to the movable contact arm and is positioned thereabout for creating a magnetic field about the movable contact arm which attracts the contact arm to the open position during severe fault conditions. The molded case housing has reinforced walls to withstand the pressures exerted on the walls of the houses during a blow open operation of the contacts.

Abstract: A contact that has two fixed contact elements and a mobile contact bridge actuated by a switching assembly and is urged by a pole spring. The connection between the mobile contact bridge and switching assembly is provided by a magnetic compensator connected to the switching assembly by means of a magnetic coupling device adapted so that, when the compensating forces rise above a given threshold, the magnetic compensator is disengaged from the switching assembly and becomes inoperative.

Abstract: A contact arrangement for an isolating switch used as a ground connection of a switch system includes two switch pieces which are movable relative to one another, one of which is a knife and the other is a gripper. The gripper includes two contact pieces which are located opposite and parallel to one another and which engage the knife in the cutting-in state. Each contact piece is in turn formed by a plurality of adjacent contact elements. Such a contact arrangement is simple and economical to produce, while providing reliable contact-making for both high and low currents in spite of only slight static contact pressure. This result is achieved because the contact elements are U-shaped contact lamellae. Each lamella includes first and second legs connected via a curved part, the first leg being supported on the knife in the cutting-in state and the second leg being supported on current terminals formed on the contact pieces.

Abstract: A circuit interrupter which comprises a pair of separable contact structures each including a contact element, at least one of the contact structures being movable between a closed position and an open position relative to the other contact structure for opening and closing an electric circuit extending through the circuit interrupter, the movable contact structure having an arm support that is pivotable about an axis, a movable contact arm pivotally supported on the arm support and extending in a parallel and an opposite direction to the other contact structure for generating an electromagnetic repulsive force therebetween, and a biasing means connected between the arm support and the movable contact arm for biasing the movable contact arm to a predetermined position with respect to said arm support, and an operating mechanism connected to the arm support of the movable contact structure for separating the movable contact structure from the stationary contact structure in response to an overcurrent flowing t

Abstract: An electrodynamically opening contact system including a fixed and a movable contact element. The movable contact is biased by a prestressed spring arrangement which is pivotally mounted at one end while at its other end slidably engages the movable contact element such that an overcenter or toggle action is effected.

Abstract: The invention concerns a very simple and effective current limiting circuit breaker of great versatility which is especially adaptable for motor control centers and combinations starters. That breaker can be used with various interchangeable trip units always with the same basic mechanism.(a) for instantaneous trip type circuit breakers of various current ratings having high interrupting capacity and low I.sup.2 t value to protect control equipment at high fault currents.(b) for high interrupting capacity thermal magnetic circuit breakers at various current ratings.(c) for circuit breakers with solid state tripping units to protect against overloads, short circuits, single phasing, underloads, etc.

Abstract: A current-limiting electric switch for low-voltage has a contact device with a contact finger and an elongated fixed contact arranged side by side. The contact finger is rotatably arranged and forms at one end a break together with the fixed contact and is at the other end provided with a flexible current connection conductor. The contact finger has its bearing point located between the two ends of a movable arm. Through the influence of electrodynamic forces from short-circuit currents, the contact finger is first rotated in one direction of rotation while maintaining the galvanic contact at the break, whereby the movable arm is displaced so that the distance between the bearing point of the contact finger and the fixed contact is increased. A stop means limits the movement of the contact finger in the first direction of rotation and brings about a continuation of the rotational movement in the opposite direction of rotation resulting in an instantaneous contact opening.

Abstract: A residential or commercial circuit breaker of the narrow width type, typically having a width of 3/4 inch or 1 inch, is provided with a magnetically permeable slot motor 102 mounted within the case 2 and around both current carrying conductors 8 and 12 for concentrating magnetic repulsive force and boosting the contact separating force.

Abstract: A residential or commercial circuit breaker of the narrow case type, typically having a width of 3/4 inch or 1 inch, is provided with a combination slot motor and arc chute 102 mounted within the case 2 and around the current carrying conductors 8 and 12. The combination slot motor and arc chute 102 concentrates the current-induced magnetic repulsive force between the conductors 8 and 12 to boost contact separation force, and also extinguishes the arc. The slot motor portion 106, 108 of the combination structure 102 continues to support the magnetic force which tends to force the arc into the arc chute portion 104 away from the contacts 10, 16 and operating mechanism. The combination slot motor and arc chute 102 is particularly simple and inexpensive, yet very effective within the size constraints of the narrow type breaker case 2.

Abstract: A residential or commercial circuit breaker of the narrow case type, typically having a width of 3/4 inch or 1 inch, is provided with a single-piece nonlaminated slot motor 102 mounted within the case 2 and around current carrying conductors 8 and 12 for concentrating magnetic repulsive force and boosting contact separation force. A dramatic increase in short circuit interruption capacity is achieved, at minimal cost.

Abstract: A molded case circuit breaker includes an operating mechanism having an integral or one-piece, rotatable, molded cross bar. The cross bar includes an enlarged section, associated with each phase or pole of the circuit breaker, having a window, pocket or enclosed opening formed therein for the receipt of a base portion of an upper movable electrical contact of a pair of separable electrical contacts. Also disposed in the opening is a compression spring and an associated spring follower positioned between the compression spring and the base portion of the upper electrical contact. The compressive spring force biases the upper electrical contact for movement in unison with the cross bar. Upon the occurrence of a high level short circuit or fault current condition, the spring follower may be downwardly deflected to enable the upper electrical contact to move independently of the cross bar.

Abstract: A molded case circuit breaker includes a movable upper electrical contact having a base portion with a slot formed therein for releasably receiving a portion of an elongated spring biased locking pin disposed in a rotatable cross bar of an operating mechanism of the circuit breaker. The locking pin is biased in the slot by a pair of tension springs secured to the cross bar, enabling the upper electrical contact to move in unison with the cross bar. Upon the occurrence of a high level short circuit or fault current of sufficient magnitude, the pin is displaced from the slot enabling the independent rotational movement of the upper contact arm. During such movement, an elongated leaf spring is downwardly deflected and then released by the base portion. Subsequently, the upper electrical contact is prevented from contacting the lower electrical contact by the engagement of the leaf spring with the base portion.

Abstract: A gas insulated switch including a tank filled with an insulating gas, wherein fixed and moving main current carrying contactors are positioned opposite each other, each including respectively fixed and moving arc electrodes installed therein and extending therefrom towards each other. According to a preferred embodiment, the fixed arc electrode includes an arc-proof end piece mounted adjacent and electrically connected to one end of an electric coil and an end ring mounted adjacent and electrically connected to the other end of the electric coil. During operation, upon opening and closing of the electrical connection between the fixed and moving arc electrodes, an arc is generated therebetween and a resultant current flows through the coil to generate a magnetic field. The magnetic field produces a force on the arc tending to rotate the arc circumferentially, whereby the arc is extinguished.

Abstract: A current limiting apparatus includes bridging electrical contacts forming a first current path across a gap in a conductor, a trigger for breaking said first current path in response to an excessive or rapidly changing level of current on said conductor, a fast acting fuse forming a second current path across said gap, for maintaining a conductive path across said gap for a predetermined length of time after breaking of said first current path, to allow the bridging electrical contacts to separate a sufficient distance from said gap to preclude arcing thereacross, and an auxiliary resistor connected across said gap to provide a relatively high resistance conductive path for current in the conductor after said fuse has blown.

Abstract: A so-called blow-off type current limiting circuit breaker includes a stationary contact strap that is divided into three elongated closely spaced coplanar parallel arms that are connected to each other at one end of the strap. The stationary contact is mounted to the interior one of the parallel arms at the end thereof remote from the one end of the strap. A terminal portion of the strap connects exterior ones of the parallel arms to one another at the ends thereof remote from the one end of the strap. A movable contact engageable with and disengageable from the stationary contact is mounted to one end of a movable contact arm that is pivoted at its opposite end in the region of the one end of the strap, extending parallel to the arms of the strap and being aligned with the interior arm. Current in the interior arm flows in a direction opposite to the direction of current flow in the exterior arms and the movable contact arm.

Abstract: A contactor capable of having a very high breaking power comprises a movable contact carrier bridge (3) having a central part in the form of a blade (3c) and conducting J-shaped pieces (2a-2b) supporting fixed contacts. A non-magnetic blade bent in the form of a U is mounted slidable inside a hollow movable insulating contact holder (1) and guides and holds at its upper end a magnetic plate (8) cooperating with said blade (3c) and forming an air-gap with another U-shaped magnetic piece (6), disposed between the legs of the bent blade (5) and integral (at 7) with the contact holder (1). A contact pressure spring (4) bears on the basis of the U-shaped magnetic piece (6) and on the bottom of the bent blade (5).

Abstract: Current limiting stationary (2) and movable (6) contacts are arranged to provide spaced, parallel oppositely directed current paths therein whereby fault currents generate electromagnetic forces for repelling the movable contact (6) from the stationary contact (2). An electrically resistive arc runner (20) has an arc transfer segment (20a) disposed along the path of movement of the movable contact (6) and is biased at one end (20b) into current carrying engagement with a stop (22) on stationary contact (2). The other end of the transfer segment (20a) is connected through a major length of the arc runner (20) to the stationary contact (2) at a point distinct from stop (22). An arc drawn between the contacts (2, 6) at separation initially passes current to the transfer segment (20a) and the stationary contact (2) through stop (22).

Abstract: A current limiting circuit breaker contains a pair of electrical contacts within separate chambers arranged side-by-side and isolated by means of an insulated barrier. The contacts are electrically connected in series such that the arcs formed between the contact pairs are magnetically motivated by the sum of the current paths through both contact pairs.

Abstract: A so-called blow-off type current limiting circuit breaker is constructed with a contact pressure spring that also holds the contact arm in open contact position when the contacts are blown open by electrodynamic forces. A multi-section cam means transmits contact opening and closing forces produced by a spring powered overcenter toggle type operating mechanism to the movable contact arm. A follower on the latter is biased into engagement with the cam means by the contact pressure spring. The cam means is so constructed that during contact blow-off the movable contact arm requires relatively little motion to move overcenter in the opening direction. One section of the cam means is constructed so that when the contact arm moves overcenter in the opening direction during contact blowoff, speed of the contact arm is controlled to an extent that contact rebound does not become a problem.

Abstract: A current limiter unit employs both a magnetic repulsion field and a gas pressure force to direct arcs to within the high voltage region of an arc chute. The unit confines the evolved gas pressure in all directions except in the direction of the arc plates. Venting the opposite end of the arc chute rapidly motivates the arc through the arc plates and out of the unit. Venting the sides of the arc chute reduces the back pressure produced by arc gases as well as the pressure exerted upon the heated breaker casing. The combination of magnetic and directed gas repulsion substantilly reduces the I.sup.2 t value of the unit. A parallel positive temperature coefficient impedance can be connected across the arc to reduce the arc current to a low enough value so that the arc becomes extinguished within a predetermined period of time.

Abstract: A so-called blow-off type current limiting circuit breaker is provided with an elongated movable contact arm that is pivotally mounted at one end thereof on a pin that projects from opposite sides of a support. The contact arm is constructed of parallel sections that are biased toward one another, by spring means disposed remote from the support, with the support being resiliently clamped between the sections to provide a good electrical connection between the support and contact arm. The pivot pin extends through aligned enlarged pivot apertures in the parallel sections to facilitate weld breaking. A wall of each pivot aperture is disposed to cooperate with the pivot pin to achieve a camming action that moves the contact arm slightly lengthwise after initial butting engagement of the circuit breaker main contacts to wipe the engaged contacts with respect to one another.

Abstract: A threshold coupling device for releasing the mobile contacts of circuit breakers when short circuits appear. A rectangular section blade (13) with longitudinal faces (13', 13") associated with a contact holder (10) is provided with balls (29, 30) which cooperate with a resilient clip (33) for providing a threshold mechanical connection between the contact (6) and an operating member (1, 2) which carries this clip. This coupling is advantageously used in circuit-breaker limiters.

Abstract: In an electric switch having a bridging contact movable into and out of engagement with a pair of fixed contacts, at least one of the terminal elements supporting the fixed contacts comprises a strip of sheet metal folded back upon itself to provide a loop shaped current path with first and second conductive sections extending generally parallel to the bridging contact on opposite sides thereof in close proximity thereto. Attractive forces electrodynamically developed between the bridging contact and the first conductive section of the one terminal element are additive to repulsive forces electrodynamically developed between the bridging contact and the second conductive section of the one terminal element for increasing contact pressure between the bridging contact and the fixed contacts under excessive current conditions.

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: The present invention combines the provision of arc shields surrounding the contacts of a circuit breaker with a magnetic driving means to raise the arc voltage of an arc drawn across the contacts and to effectively drive the arc, whereby the performance of the circuit breaker is improved.

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: 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.