Abstract: This electrical switchgear has an interrupting chamber enclosing an interrupting gas (G) substantially devoid of SF6 and of CF4, and a first arcing contact (10) and a second arcing contact (18), the two arcing contacts moving causes an electric arc (26) to strike, while at least one irradiation wall (22) is provided that is suitable for being reached by the electric arc. At least two component materials that are part of at least one element selected from the interrupting gas, the first and second arcing contacts, and the or each irradiation wall, are suitable for decomposing under the effect of the electric arc, so as to form decomposed species (e1, e2) suitable for combining in the interrupting chamber, in order to form at least one new gaseous species (G1), before the electric arc is extinguished, the dielectric properties of said at least one new gaseous species being superior to the dielectric properties of said interrupting gas (G).

Abstract: A gas-insulated equipment such as a gas-insulated switchgear provided according to the invention can efficiently improve dielectric strength of an entire electrode system considering electric field distribution of the electrodes and conductors and improving insulation coordination so that miniaturization of the entire device can be achieved. The gas-insulated switchgear includes insulating gas sealed within an earth metal container and an insulating spacer insulating and supporting high-voltage receiving portions. Surfaces of shielding electrodes having a larger diameter than that of high-voltage conductors are covered with thick dielectric coatings, and surfaces of the high-voltage conductors are covered with thin dielectric coatings.

Abstract: The heavy-duty circuit-breaker with arc blowing has an element which is sensitive to hot gas and/or to gas pressure and is protected by means of a seal against a hot-gas flow. The seal is advantageously a movable non-contacting seal. The seal has a channel entrance for production of a partial hot-gas flow of the hot-gas flow and, connected downstream from this, a channel in order to reduce the mass flow of the partial hot-gas flow, and an expansion chamber in order to expand the volume of the partial hot-gas flow. The expansion chamber is a pressure-relief area. The element may, for example, be a guide element, a contact-making element or a sealing element.

Abstract: The invention relates to a switch assembly comprising an essentially tubular enclosed housing. The tubular axis of the enclosed housing deviates from the horizontal and the vertical. The switch assembly comprises an interrupter unit, to which three main leads are connected.

Abstract: A vacuum insulated switchgear comprising a case having a switch section, a bus-bar section and a cable section, each being partitioned by an earthed metal plate, a vacuum double break three point switch disposed in the switch section and having breaking and disconnecting function, an operator, a bus-bar disposed in the bus-bar section of the case, and a cable connection terminal connected to a cable in the cable section.

Abstract: The heavy-duty circuit-breaker having an axis (A), and having an arcing contact piece, a current-carrying element and an erosion protection element, with the arcing contact piece having an opening in order to carry an essentially axial flow of a gas which has been heated by an arc, and together with the current-carrying element forms a flat contact (F) in order to carry a short-circuit current (I) which flows through the arcing contact piece and the current-carrying element, and with the erosion protection element essentially shielding the current-carrying element from the flow close to the flat contact (F), is characterized in that the current-carrying element has an axial area in which a radial internal dimension (d2) of the current-carrying element increases in steps or continuously as the distance from the flat contact (F), measured parallel to the axis (A), increases.

Abstract: A load center system includes a primary bus bar with primary stabs for receiving a first type of circuit breaker, the primary stab extending from a primary base portion of the primary bus bar. A secondary bus bar with a secondary base portion and secondary stabs is coupled to the primary bus bar in a generally overlapping position, for receiving a second type of circuit breaker. Both the primary and secondary bus bars can be formed from stamping. By utilizing bus bars with base portions, the primary and secondary bus bars together provide for ease of assembly, and structural integrity, while allowing either of the first type of circuit breaker and the second type of circuit breaker to be coupled to the load center.

Abstract: A method of evacuating hot gases produced in a current breaking operation by a high voltage circuit breaker (1) which comprises a metal outer tank (2) filled with insulating gas, a casing (3) having gas outlet ports (30) and arranged inside the metal outer tank (2), with which it is in communication via the said ports, characterized in that insulating gas (GI) is aspirated from inside the casing (3) in a direction parallel to the flow of the hot gases (GC) produced by the current breaking operation, so as to mix the gases inside the casing (3) before they are evacuated, through the said gas outlet ports (30) of the casing, into the interior of the metal outer tank (2). The invention also relates to an associated high voltage circuit breaker, which includes means (5) for aspirating insulating gas from the interior of the casing (3), in a direction parallel to the hot gas stream.

Abstract: The gas-blast circuit breaker includes an electrically conductive vessel charged with insulating gases and kept at earth potential, a stationary arc-extinguishing chamber accommodated in a ground metal tank and corresponding to a moving part to extinguish an arc generated between it and the moving part, an insulating member that supports the stationary arc-extinguishing chamber to insulate the same from an earth potential portion, an opening provided on the ground metal tank, and a lid body that closes the opening provided on the ground metal tank and is arranged detachably on the opening from outside the ground metal tank, and one end of the insulating member is mounted to a mount provided on the lid body, and therefore a gas-blast circuit breaker is obtained to enable ensuring a sufficient insulation distance and appropriately and easily performing working of and a mount work of mount portions of an insulating member.

Abstract: An exemplary circuit breaker has in an enclosure filled with an insulating gas at least one interrupting chamber extending along a longitudinal axis. The interrupting chamber can be configured radially symmetrically and contains an arcing volume and at least two associated arcing contacts. The arcing volume is actively connected to at least one exhaust having an exhaust volume. The exhaust is constructed for cooling hot gases generated during breaking operations and is connected to a volume of the interrupting chamber. The breaking capacity of this circuit breaker can be increased significantly and the exhaust can be constructed in a comparatively simple and cost effective manner. This can be achieved by providing in the area of the exhaust at least one forcibly created recirculation area which increases the flow resistance of the hot gases.

Abstract: The switchgear assembly has a polyphase design and has a gas-filled, modular encapsulation for each phase. Provided as the modules are at least one busbar, which is guided predominantly horizontally, a circuit breaker and two combined disconnecting-earthing switches having a disconnection and grounding function. A first one of the combined disconnecting-earthing switches supports a section of the busbar and is connected between the busbar and a first current terminal of the circuit breaker. The second combined disconnecting-earthing switch is connected between an outgoing feeder or a further busbar of the assembly and the second current terminal of the circuit breaker. The combined disconnecting-earthing switches are aligned such that two drive apparatuses, which are provided for their actuation, point in the same, predominantly horizontal direction.

Abstract: The high-voltage metal-clad substation element comprises at least one circuit-breaker connected electrically and mechanically to at least one set of busbars (3, 4) extending along an axis (D) that extends transversely to the longitudinal axis (AX) of the circuit-breaker. The metal case (1) is fixed to the ground via a hinge which allows the case to tilt slightly when said set of busbars (3, 4) expands along said transverse axis (D). This configuration makes it possible to omit or to reduce the use of axial bellows on the set of busbars, thereby reducing the cost of manufacturing the metal-clad substation. Advantageously, in association with the hinge, the metal case is designed to have some flexibility to reduce mechanical stresses when the set of busbars expands.

Abstract: An exemplary circuit breaker includes at least one arcing chamber that is filled with isolating gas, extends along a longitudinal axis, is designed to be essentially radially symmetrical, contains an arc area and has at least two power contact pieces. At least one of the power contact pieces is in the form of a moving or stationery tubular hollow contact, which is provided for dissipating hot gases from the arc area into a concentrically arranged exhaust body. A deflection device, which interacts with at least one opening in the hollow contact, is arranged on the side of the hollow contact facing away from the arc area, and radially deflects hot gases into the exhaust volume, which is connected through at least one second opening to an arcing chamber volume. An increased disconnection rating is achieved by providing at least one intermediate body between the hollow contact and the exhaust body.

Abstract: In a gas-insulated switchgear tank in which an electric insulating characteristic is improved by a gas, and which has a vacuum circuit-breaker, a disconnecting switch, and a container in which container the vacuum circuit-breaker and the disconnecting switch are arranged and an inside of which container is adapted to be hermetically sealed and filled with the gas in such a manner that the vacuum circuit-breaker and the disconnecting switch are at least partially surrounded by the gas, the gas includes N2 and O2.

Abstract: The invention relates to a power switch (100) that comprises a contact element (105, 107) mobile in an axial direction and an extinction gas flow that moves in said axial direction when the switch is actuated. Said extinction gas flow is coaxially surrounded by a flow guide device (1, 1a,b,c) one surface area of which is provided with at least one discharge opening (10a,b,c,d,e,f,g,h,i,j,k,l; 12a,b,c,d,e,f) for deflecting at least a part of the extinction gas flow towards a discharge direction, said discharge direction being oriented tangential and substantially at an angle to the axial direction.

Abstract: A high for medium voltage gas insulated earthing switch comprises at least one conducting bar in an enclosure, with a corresponding earthing contact and a phase contact fixed to the said bar that will be electrically connected to the earthing contact to earth the said bar. The earthing contact is installed fixed in the enclosure facing the phase contact, leaving a free space (E) between this phase contact and the earthing contact. A switching element is installed free to move in the enclosure between the phase contact and the earthing contact, and comprises firstly a switching contact that short circuits the space left free (E) to electrically connect the earthing contact and the phase contact when the earthing switch is closed, and secondly an at least partly electrically insulating support on which the switching contact is fixed such that the switching contact is electrically isolated from the phase contact and from the earthing contact when the earthing switch is in an open position.

Abstract: This circuit-breaker has at least one arcing chamber which is filled with isolating gas, extends along a longitudinal axis, is designed to be essentially radially symmetrical, contains an arc area and has at least two power contact pieces. At least one of the power contact pieces is in the form of a moving or stationery tubular hollow contact, which is provided for dissipating hot gases from the arc area into a concentrically arranged exhaust body. A deflection device, which interacts with at least one opening in the hollow contact, is arranged on the side of the hollow contact facing away from the arc area, for the radial deflection of the hot gases into the exhaust volume, which is connected through at least one second opening to an arcing chamber volume. The aim is to increase the disconnection rating of this circuit-breaker. This is achieved by providing at least one intermediate body between the hollow contact and the exhaust body.

Abstract: A preferred embodiment of a circuit breaker includes a tank having a main portion for housing an interrupter assembly, a bushing insulator adhesively bonded to the tank, and an electrical conductor extending through the bushing insulator and electrically coupled to the interrupter assembly.

Abstract: A switching mechanism of a circuit breaker for a gas insulated switchgear is able to extinguish arc gas by changing a volume of a compressing chamber without increasing a stroke of a movable cylinder and without increasing required output power of an actuator.

Abstract: A switchgear wherein a connecting portion to be connected to a transmission side branch bus container and a connecting portion to be connected to a receiving side branch bus container are provided on a circuit breaker container in an up and down relation so as to face the same direction. Any one of the transmission side branch bus container and the receiving side branch bus container is connected to the connecting portion positioned on the upper side, and the other is connected to the connecting portion positioned on the lower side, and a transmission side power cable terminal container or a receiving side power cable terminal container is arranged at a position deviated horizontally from the axis of the transmission side branch bus container or the receiving side branch bus container.

Abstract: In a high-voltage circuit breaker having two arcing contacts arranged coaxially relative to one another and having an insulating nozzle which in the closed state is blocked by a first arcing contact the first arcing contact has a shaft having a greater diameter and an end element having a smaller diameter, the shaft blocking a through-channel of the insulating body. The through-channel is cylindrical along a length that is smaller than the length of the end element. As a result, the extinguishing gas starts to flow when the end element is pulled back into the through-channel.

Abstract: A contact zone (1) of a quenching chamber which is arranged rotationally symmetrical about a central axis (2) and is filled with an insulating medium, having at least two stationary consumable contacts which are in the form of contact rings (4, 15) and which, when the quenching chamber is closed, are electrically conductively connected by means of a bridging contact which is arranged centrally and can move axially. The mutually facing end surfaces of the consumable contacts are partially covered by electrically insulating covers (11, 22). The aim is to provide insulating covers which are designed to have good dielectric characteristics and are easy to install.

Abstract: A gas-insulated switch gear has a plurality of bay units having bus ducts each containing a three-phase bus and connected by bellows expansion joints. When the bay unit needs to be inspected for maintenance, the bellows expansion joints are compressed, and only the bay unit can be pulled out of the gas-insulated switchgear.

Abstract: The movable conductors of a three-phase isolation switch are incorporated into the electrically insulative molded shaft, thereby mechanically supporting them and isolating them from the metal axle of the shaft. Movable contacts on the ends of each movable conductor are angularly spaced by &agr; degrees, where &agr; is less than 180° and is 90° in the exemplary embodiment. A common fixed load contact is located angularly between, and spaced &agr; degrees from, both the fixed line and ground contacts so that the shaft is rotated only &agr; degrees between a first, closed position, in which the movable conductors connect the fixed load contact for each phase to the corresponding fixed line contact, and a second, grounded position, where the fixed load contact of each phase is connected by the movable conductor to the corresponding fixed ground contact.

Abstract: A hybrid gas insulation switchgear apparatus comprises an enclosure in which an insulating gas is sealed, a bushing unit provided for the enclosure, a breaker unit disposed inside the enclosure, a disconnector unit disposed inside the enclosure and including disconnectors to be connected electrically in series to both sides of the breaker unit, an earth switch unit disposed inside the enclosure and including earth switches disposed between the breaker unit and the disconnectors, respectively, the earth switches being provided with main pole side electrodes disposed on the side of the breaker unit, and a current transformer unit mounted to the enclosure. The bushing unit including bushings each having a conductor connected to an electrode in the disconnector on a side opposite to the breaker.

Abstract: A circuit breaker having a hybrid arc-extinguishing function includes: an upper shell; a lower shell coupled to the upper shell to form an extinguishing chamber (S) filled with an insulation gas; a movable electrode movably installed at the upper shell and having an exhaust channel for discharging a gas inside the extinguishing chamber (S) outwardly; a fixed electrode having an exhaust channel fixed at the lower shell and positioned at a coaxial line with the movable electrode, through which the gas inside the extinguishing chamber (S) is discharged outwardly, the movable electrode being movable being movable to a position where it contacts with the fixed electrode and to a positioned where it is separated from the fixed electrode; a magnetic coil arranged around the fixed electrode to form a magnetic field for a rotation of an arc, and receiving a conductive current from the movable electrode as being shared with the fixed electrode when the movable electrode is positioned contacting with the fixed electrode

Abstract: A current collector, in which contact portions are free from dissolved loss even both fixed and moving contacts slidingly contact with each other, and durability as well as a current-carrying perfomance is improved, including a container, which is filled with an insulating arc-extinguishing medium and in which a cylindrical-shaped fixed contact and an torus-shaped contact disposed concentrically with the fixed contact and adapted to come into fitting contact with the fixed contact to carry current are received, and a torus-shaped current collecting member formed from a conductive material and provided on a contact portion of the torus-shaped contact.

Abstract: A gas-insulated switchgear of an 1½ CB system, in which three circuit breakers are electrically connected in series between a pair of buses and a connecting line for supplying and receiving electric power is led out from between the circuit breakers, is characterized in that new connecting lines for supplying and receiving electric power are led out from the main buses through disconnecting switches to a diameter which is an end portion of the gas-insulated switchgear. A leading out side of the connecting lines is outside the main bus, and an installation area of the gas-insulated switch gear is not increased.

Abstract: A shorting switch includes a vacuum switch having fixed and movable contact assemblies and a driven member. A spring cover tube and bushing mount the driven member for linear movement along a path substantially parallel to a longitudinal axis of the movable contact assembly. The driven member moves the movable contact assembly between open and closed circuit positions. A compression spring has a compressed state and a released state, which moves the driven member and movable contact assembly to the closed circuit position. A release bolt has an opening therein and is coupled to the driven member to normally maintain the compression spring in the compressed state. A charge is disposed in the opening of the release bolt and is actuated to fracture the release bolt and release the compression spring to the released state. First and second terminals are respectively electrically interconnected with the fixed and movable contact assemblies.

Abstract: Insulating component for high-voltage systems, and a method for its production In an insulating component (9, 18) for high-voltage systems, in particular gas-insulated systems, the invention provides for the material of the component to be treated with alpha, beta or gamma radiation in order to increase the conductivity, at least in a region (10, 16) of its surface in which it is subject to higher dielectric loading during operation than in other regions.

Abstract: A switching mechanism of a circuit breaker for a gas insulated switchgear is able to extinguish arc gas by changing a volume of a compressing chamber without increasing a stroke of a movable cylinder and without increasing required output power of an actuator.

Abstract: A highly reliable gas circuit breaker capable of improving the braking performance and the insulating performance and a gas circuit breaker capable of allowing a stress acting on the supporting member of the electrode are provided. The gas circuit breaker comprising a grounded tank filled with an insulation medium; a movable electrode arranged inside the grounded tank; a fixed electrode which is supported through an insulator supporting member inside the grounded tank and disposed detachably from and oppositely to the movable electrode; and electric conductive parts individually provided in the movable electrode and the fixed electrode, wherein the insulator supporting member is a solid cone and supports the fixed electrode in an upper side of a central axis of the grounded tank.

Abstract: A high-voltage circuit-breaker including a valve for decompressing a thermal blast chamber includes two contacts disposed in a breaking space which is delimited by a blast nozzle and contains a dielectric gas. It further includes a thermal blast chamber which communicates with the breaking space via a throat of the nozzle and with an expansion space via an evacuation passage which can be shut off by a valve. The valve opens when the pressure in the thermal blast chamber is greater than a particular threshold to evacuate the pressurized gas from the chamber. The evacuation passage is formed in the nozzle and defines a circular volume within the thickness of the nozzle, following its general shape, and opening into the expansion space downstream of the breaking space relative to the throat.

Abstract: A current collector, in which contact portions are free from dissolved loss even when both fixed and moving contacts slidingly contact with each other, and durability as well as a current-carrying performance is improved, including a container, which is filled with an insulating arc-extinguishing medium and in which a cylindrical-shaped fixed contact and an torus-shaped contact disposed concentrically with the fixed contact and adapted to come into fitting contact with the fixed contact to carry current are received, and a torus-shaped current collecting member formed from a conductive material and provided on a contact portion of the torus-shaped contact.

Abstract: A gas-insulated switchgear includes a sealed vessel filled with an insulating gas, a circuit breaker held in the sealed vessel, and a branch pipe attached to a lower part of the sealed vessel right below the circuit breaker. The branch pipe defines a hand hole for use in inspecting the circuit breaker, provides a place for installing an absorbent container and forms a foreign matter collecting space.

Abstract: A pressurized gas circuit-breaker pole includes a first enclosure or pole head having a first envelope with a first connecting flange including a circular orifice. The envelope contains a first mobile assembly terminating in a coupling member coaxial with the orifice. A second enclosure constituting an insulative column includes a second envelope having a second connecting flange with a circular orifice. The second envelope contains a second mobile assembly having a link for maneuvering the first mobile assembly and its end including complementary arrangements for coupling it with the coupling member. The connecting flange of each enclosure has an annular elastomer seal fixed to the corresponding connecting flange and through which the corresponding mobile assembly passes. The seal of each enclosure provides, during assembly of the flanges and coupling of the internal mobile assemblies, a sliding seal. The seal is broken on completion of assembly.

Abstract: Disclosed herein is a gas-blasted circuit-breaker comprising a movable arc contact; a fixed arc contact opposed to the movable arc contact; an insulating nozzle disposed at the movable arc contact on the fixed arc contact side thereof; a puffer cylinder disposed on the side opposite to the insulating nozzle; a hollow conductor that holds the fixed arc contact opposed to the insulating nozzle; an insulating rod connected to the puffer cylinder; and a fixed piston fitted inside the puffer cylinder; wherein an insulating gas is ejected to a space between the puffer cylinder and the fixed piston by driving the insulating rod and is sprayed to an arc generated upon interruption of a current; and wherein the hollow conductor is in a cylindrical shape having a cross section parallel to the axis thereof, the cross section being smaller in diameter on the downstream side of a flow of insulating gas, the hollow conductor having a closed end on the downstream side of the flow of insulating gas, and the hollow conductor

Abstract: The drive rod for high-voltage switchgear that is insulated with a dielectric gas comprises a segment made of an electrically-insulating material and two metal end pieces fixed to respective ends of the segment, as well as a thermal shield that is made of an electrically-insulating material, that is disposed between the end pieces, and that surrounds the insulating segment while being spaced apart therefrom to define an annular gap serving to be filled with the dielectric gas. In this way, the insulating segment of the rod is protected against thermal attack from electric arcs.

Abstract: A gas-insulated switchgear includes a sealed vessel filled with an insulating gas, a circuit breaker held in the sealed vessel, and a branch pipe attached to a lower part of the sealed vessel right below the circuit breaker. The branch pipe defines a hand hole for use in inspecting the circuit breaker, provides a place for installing an absorbent container and forms a foreign matter collecting space.

Abstract: The three-position, gas-insulated, metal-clad electrical switch inside a metal casing includes first and second break contacts, a fixed grounding contact, and a switching element that is movable in an axial direction to interconnect the break contacts. The first and second break contacts and the fixed grounding contact are superposed in the axial direction, and the switching element is moved by a drive rod which passes through the fixed grounding contact, thereby enabling the switching element to occupy each of the three switching positions including a grounding position in which it connects the first break contact to the fixed grounding contact.

Abstract: A high- and medium-voltage gas-insulated switchgear device having a casing. The casing includes an interruption unit having at least one fixed contact and one moving contact that can couple with each other, and a first actuator that is operatively connected to the moving contact. The casing also includes a disconnection unit electrically connected to the interruption unit. The disconnection unit has at least one fixed contact and one moving contact that can couple with each other, and a second actuator that is operatively connected to the moving contact. At least one of the actuators includes a motor with position control.

Abstract: In a hybrid type gas insulation switch gear apparatus, a main enclosure including a first cylindrical section have a base and a second cylindrical section branched from the base. A bushing is mounted on the cylindrical section and including a hollow insulating housing having a housing space and a central conductor extended in the hollow insulating housing. A first insulating spacer is provided in the first cylindrical section and configured to separate the first hollow space into first and second segment spaces. An insulating enclosure is also mounted to the second cylindrical section and including an enclosure space. A second insulating spacer is provided between the insulating enclosure and the second cylindrical section and configured to separate the enclosure space from the second hollow space. A disconnecting switch is formed in the first segment space of the first cylindrical section and a circuit breaker is also formed in the insulating enclosure.

Abstract: A hybrid gas insulation switchgear apparatus comprises an enclosure in which an insulating gas is sealed, a bushing unit provided for the enclosure, a breaker unit disposed inside the enclosure, a disconnector unit disposed inside the enclosure and including disconnectors to be connected electrically in series to both sides of the breaker unit, an earth switch unit disposed inside the enclosure and including earth switches disposed between the breaker unit and the disconnectors, respectively, the earth switches being provided with main pole side electrodes disposed on the side of the breaker unit, and a current transformer unit mounted to the enclosure. The bushing unit including bushings each having a conductor connected to an electrode in the disconnector on a side opposite to the breaker.

Abstract: A compact-sized gas insulated switchgear accommodates components and devices constituting its line side unit into one container. Arresters and cable heads are accommodated in a lower section of the line side unit, and a circle connecting centers of respective arresters and cable heads arranged therein is concentric with a cylindrical section of the line side unit container.

Abstract: In order to provide a gas circuit breaker capable of reducing a remarkable degradation of dielectric strength in the vessel caused by hot gas and which can be downsized, the present invention is characterized by a hot gas discharge mechanism of the movable opening/closing mechanism, which is designed to ensure that the hot gas separated and fed to a movable opening/closing mechanism is discharged from an exhaust outlet 19b toward the side opposite to the puffer chamber 26 of the gas discharge chamber 28 formed on the rear of the puffer chamber 26, and gas is discharged toward the inner surface of the vessel 4 through the exhaust outlet 23b after gas temperature and velocity have been interrupted by convection of the gas in the puffer chamber 26. This structure interrupts a remarkable degradation of dielectric strength in the vessel resulting from direct blowing of hot gas onto the inner surface of the vessel 4.

Abstract: The hybrid-type interrupter device for high or medium voltage comprises:

Abstract: A switching device has an improved fastening arrangement to join an electrical insulating body with a conductive metal mounting piece or flange. The fastening arrangement involves a plurality of standard hardware fasteners. The quantity of fasteners required to join the insulating body and flange is dependent upon the desired strength of the joint and the size (or diameter if the insulating body is tubular shaped) of the insulating body.

Abstract: The arc blast switch can have single or dual contact movement and possesses a break chamber with low gas compression, the switch includes a first contact and a second contact, the first contact being movable in a longitudinal axis and being secured to the break chamber in which the gas is compressed by a piston. A device for displacing the piston is arranged so that its movement changes direction inside the case of the switch after the gas compression stage, and the device includes a telescopic link connected to the piston. The length of the displacement of the piston inside the case during the compression stage is not less than the length of the displacement of the first contact during the compression stage.

Abstract: An insulating blast nozzle for a circuit breaker, the circuit breaker having a first arcing contact and a second arcing contact that separate from each other when the circuit breaker is opened subsequent to prior separation of permanent contacts, said insulating blast nozzle being secured to one of the permanent contacts and being generally horn-shaped, having a throat and defining a volume of revolution having an upstream portion and a downstream portion joined by the throat, in which the inside volume is cylindrical and closed by the second arcing contact when the circuit breaker is closed and for a few milliseconds after the arcing contacts have separated, the wall of the nozzle in its portion defining the upstream portion of said volume of revolution surrounding said first arcing contact, the downstream portion of said volume comprising a first conical portion, wherein said first conical portion is followed by a second conical portion having a flare angle that is more open than that of said first conical

Abstract: An electric switch includes a first arcing contact surrounded by a puffer break chamber in which the gas is pressurized by the thermal effect, and a second arcing contact movable along an axial direction relative to the first arcing contact. The break chamber includes an inner partition separating a first compartment of fixed volume from a second compartment of smaller volume, both compartments being filled with the gas under pressure and each possessing an orifice to blast the arc, the orifices being separate and placed in series along the axial direction. Each compartment is connected to its own orifice via a respective blast channel. The compartments communicate with each other via a channel that is closed by an excess pressure vent device allowing gas at excess pressure to pass in one direction only from the smaller volume compartment to the larger volume compartment.