Abstract: An electromagnetically operated, straight-line motion dual-break electrical contactor has current conductors entering a contact area from opposite directions. In the contact area the conductors are closely spaced and have finite parallel substantially flat portions with an insulative divider to prevent conductor to conductor arcing. A pivotable contact carrying bridge spans the conductors. The pivotable bridge compensates for contact wear or displacement. Screens are arranged in arc blow paths to aid in extinguishing arcs. The contactor arrangement and spacing controls the direction and enhances the magnitude of arc blow.

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: 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 modular vault type load break switch wherein the switching assembly is carried within an oil filled vault such that the operation of the switching mechanism is independent of the vault structure. The switching contact mechanism employs a positive actuator which is energized by the operator and contact movement effected by a remotely controlled mechanism independent of operator contact.

Abstract: A switching device, with a mechanism similar to that of a D'Arsonval galvanometer, acting responsive to current flow in a primary control circuit to close a switch in a secondary controlled circuit. The primary control circuit includes dual oppositely wound coils, and relative pivotal mounting is provided between the coils and permanent magnets. The pivotal movement therebetween, upon current flow, closes the switch.

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 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 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 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: An electric circuit breaker includes means for providing a predetermined delay between the initiation of a command pulse and the mechanical operation of an element of the circuit breaker in response to the command pulse. In one embodiment, the predetermined delay is provided between a tripping command pulse and the mechanical operation of the trip mechanism of a vacuum circuit breaker. In this embodiment, a translatable armature is coupled to the trip mechanism through mechanical linkage including a flywheel rotatably mounted on a shaft. The shaft is mechanically coupled to the trip mechanism wherein rotation of the shaft operates the trip mechanism. The translatable armature is mechanically coupled to the flywheel so that movement thereof causes the flywheel to rotate through a predetermined rotation. The flywheel includes impact imposing means extending outwardly from a major face thereof. The shaft includes impact receiving means extending radially therefrom.

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 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: 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: An electromagnetic contactor characterized by stationary and movable contacts operable between open and closed positions by an armature of an electromagnet which is movable between energized and deenergized positions, and latch means for latching the armature in the energized position to hold the contacts in the closed position when the load current through the contact exceeds a predetermined value even though the electromagnet means is deenergized.

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 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 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 resettable high-voltage fusing device including a vacuum interrupter and an arrangement of magnetically displaceable rod members which are displaced by the magnetic forces resulting from overload currents flowing through them. For currents below the "blow" rating, a spring arrangement keeps the rods in place by applying axially opposing forces at the ends thereof, and the vacuum interrupter is kept closed. After rod displacement caused by overload current the vacuum interrupter opens in response to one of the springs released by displacement of the rods.

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: An electric circuit breaker comprises first and second contacts, which engage each other while the circuit breaker is fully closed and both of which are movable. During the initial portion of an opening operation, the two contacts move together and remain engaged. First electromagnetic-assist means develops while the contacts are engaged a magnetic force on the first contact varying directly with current through the contacts which urges the first contact toward the second contact. Second electromagnetic-assist means develops while the contacts are engaged a magnetic force on the second contact varying directly with current through the contacts which urges the second contact toward the first contact. Means is provided to block motion of the first contact with the second contact after initial opening motion of the second contact and to prevent during subsequent opening motion of the second contact the transmission of force from the first electromagnetic-assist means to the second contact.

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: This electric circuit breaker contains electromagnetic-assist means for opposing the contact-repulsion forces developed when a high current flows through the breaker. The assist means comprises a rigid supporting member which can be restrained in a fixed position to render the assist means capable of transmitting closing force to the movable contact of the breaker but which supporting member is releasable to render said assist means generally ineffective to transmit closing force to said movable contact. The assist means further comprises a toggle connected between the supporting member and the movable contact for imparting a closing force to the movable contact when forced toward an in-line position while said supporting member is restrained.For forcing the toggle toward its in-line position, there is provided magnetic structure cooperating with a conductor connected in series with the circuit breaker contacts.

Abstract: A current limiting circuit interrupter having a movable contact arm disposed within a magnetic drive structure and a pair of contacts disposed within a magnetic arc driving structure is provided. The magnetic drive or slot motor rapidly moves the movable contact arm to separate the contacts upon a predetermined overload. When high overload currents pass through the contactor arm extremely fast separating movement occurs between the contacts providing current limiting. In one embodiment there is provided a pair of relatively stationary spaced apart contacts bridged by an elongated movable contact arm which can be moved away from the stationary contacts to establish two serially related arcs. At each end of the bridging contact there is provided a surrounding magnetic structure or yoke which magnetically impels any arc formed during circuit interruption to move laterally outward into an arc extinguishing structure. The arc extinguishing structure can comprise non-magnetic metallic spaced apart plates.

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: In order to eliminate contact bounce and electrodynamic repulsive forces upon closure in a standard high rating circuit breaker device when a fault exists, an armature is disposed on the movable contact assembly and an iron core pole is disposed adjacent the stationary contacts, the normal current path providing a partial turn about the core. As current passes through the contact assembly the resulting magnetic field attracts the armature and hence the movable contact assembly toward the stationary contacts.

Abstract: An electric switch is disclosed in which the swingable arms intended to approach and separate the fixed and movable contacts are a part of a linkage containing fixed and slidable pins, so that an overcurrent exceeding a preselected limit causes the contacts to be opened without rebounds. The existing, or specially provided clearances between the component parts of the linkage are exploited for providing yieldable end of stroke abutments for absorbing the shock of the contact-carrying arm.

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: The disclosed instantaneously tripping device includes a stationary iron core encircling a conductor and responsive to a flow of shortcircuiting current through the conductor to attract a movable iron core to open contacts. A locking and releasing plate are operatively coupled to the movable core to transfer the movement of a closing latch to the latter. After the completion of the closing operation effected by a switching mechanism, the locking plate locks the movable core while only during the closing operation of the switching mechanism does the releasing plate release the movable core to permit it to be attracted by the stationary core.