EP1359596B1 - Electrical switching device having an arc extinguishing chamber with deionization plates - Google Patents

Electrical switching device having an arc extinguishing chamber with deionization plates Download PDF

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Publication number
EP1359596B1
EP1359596B1 EP03354028A EP03354028A EP1359596B1 EP 1359596 B1 EP1359596 B1 EP 1359596B1 EP 03354028 A EP03354028 A EP 03354028A EP 03354028 A EP03354028 A EP 03354028A EP 1359596 B1 EP1359596 B1 EP 1359596B1
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EP
European Patent Office
Prior art keywords
fins
arc
chamber
contact
volume
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP03354028A
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German (de)
French (fr)
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EP1359596A1 (en
Inventor
Richard Schneider Elec. Industries SAS Charles
Stéphane Schneider Elec. Industries SAS Dye
Luc Schneider Elec. Industries SAS Moreau
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Schneider Electric Industries SAS
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Schneider Electric Industries SAS
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Publication of EP1359596A1 publication Critical patent/EP1359596A1/en
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
    • H01H1/14—Contacts characterised by the manner in which co-operating contacts engage by abutting
    • H01H1/20—Bridging contacts
    • H01H1/2041—Rotating bridge
    • H01H1/2058—Rotating bridge being assembled in a cassette, which can be placed as a complete unit into a circuit breaker
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/30—Means for extinguishing or preventing arc between current-carrying parts
    • H01H9/34—Stationary parts for restricting or subdividing the arc, e.g. barrier plate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/30—Means for extinguishing or preventing arc between current-carrying parts
    • H01H9/34—Stationary parts for restricting or subdividing the arc, e.g. barrier plate
    • H01H9/346—Details concerning the arc formation chamber

Definitions

  • the invention relates to an electrical switchgear, in particular a limiting device such as a limiting circuit breaker, whose external manifestations during the cut are reduced or nonexistent.
  • a conventional arc extinguishing chamber for electric circuit breaker low voltage power.
  • the chamber is located opposite the separable contacts of the circuit breaker, and provided with gas evacuation ports on a rear wall opposite the contacts.
  • Flat metal fins are disposed within the chamber, between the contacts and the gas discharge port, perpendicular to the side walls.
  • the separation of the contacts causes an electric arc that is projected into the chamber by an electromagnetic loop effect.
  • the bow meets the fins that absorb some of its energy.
  • the arc also exchanges with the side walls of the chamber, which are made of synthetic gas-forming material.
  • the arc cools gradually and its voltage rises so that when the current passes through zero, the arc goes off permanently.
  • the thermal and kinetic effects of the arc plasma during the cutoff cause a sudden increase in the pressure in the extinguishing chamber.
  • the exhaust ports allow the exhaust gas to escape and contain the pressure at an acceptable level within the housing of the unit. This evacuation of partially ionized cutoff gas imposes, however, minimum distances of safety between devices on the same electrical panel, to avoid any risk of ignition between neighboring parts under tension. It also requires that arrangements be made for overpressure not to damage the painting itself. In addition, exhaust gases can be considered as pollutants and must therefore be filtered.
  • Electrical switching devices are also known whose housing is sealed, so as to eliminate any external manifestation during the cut, such as described for example in the document GB 2,119,575 . It is then necessary to provide the housing with high performance sealing devices and to reinforce its mechanical resistance to pressure. Sealing is obtained at the cost of a reduction in cut-off performance compared to conventional equipment of the same volume. In addition, the cost of such devices compared to conventional devices is very high, so they are implemented only under extreme conditions, for example in explosive environments.
  • a low-voltage circuit breaker with sealed power is described in the document WO95 / 08832 .
  • This circuit breaker comprises an arc extinction chamber disposed opposite the contacts and provided with cooling fins which are arranged between the contacts and an outlet opening of the chamber.
  • a recirculation channel directs gases from the chamber outlet to the drive mechanism of the contacts through a deionization filter. The gases emitted during the breaking at the arc extinguishing chamber thus flow in closed circuit in the housing and are finally redirected to the contacts and to the chamber inlet, after having been cooled and deionized .
  • This important convection promotes rapid movement of the arc inside the chamber, which is considered in this document as particularly advantageous for accelerating the cut.
  • the arc is deflected on one or the other side and returns to the contacts by dividing between the fins, then is restored between the contacts before being projected again in the room .
  • the foot of the arc follows a loop path until the arc energy has been dissipated in the fins.
  • the fins are thus used homogeneously.
  • the circulation of the arc gives rise to periodic rebooting of the arc on the contacts, which damage the contacts.
  • arc extinguishing plates are described for an arc extinguishing chamber of an electrical switchgear.
  • the plates have a cut forming a flared neck in U or V extended by a slot opening on a circular widening. This shape is supposed to ensure a good location of the arc and its rapid extinction. It is intended to cover the extinguishing plates with an insulating material, plastic or ceramic, including polytetrafluoroethylene, so as to stabilize the positioning of the arc in the enlarged circular portion.
  • the plates may be made of soft iron and covered, at least in the circular enlarged portion, with a soft, magnetic electrical insulating material to prevent the arc from forming a foot on the periphery of the widening.
  • the arc can be located in the widened circular part, but nothing is planned to ensure its extinction.
  • the arrangements made to stabilize the arc and prevent the formation of a foot arc result in the energy exchange between the arc and its environment is very small.
  • the arc can only exchange with the edges of the plates, at the level of the circular widening. The lateral part of the plates is therefore not used effectively for the cooling of the arc.
  • the treatment of the plates in several layers of different materials considerably increases the cost of the device.
  • the invention therefore aims to overcome the drawbacks of the state of the art, so as to propose, in a reduced volume, a cutting apparatus performance and external manifestations greatly reduced.
  • the corridor and the chimney allow the bow to settle quickly and stably at the bottom of the chamber, in the area in section has an oblong shape. It is known that the arc naturally tends in an open environment to assume a generally circular cylindrical shape. The oblong shape of the chimney thus contributes to a strong constriction of the arc, hence a significant energy exchange with the fins and the walls at this level. A convective gas stream is established between the fins, laterally with respect to the corridor, and allows cooling and deionization of the gases in contact with the fins, until the arc is extinguished. This rapid cooling of the gases considerably limits the rise in pressure in the chamber. External manifestations are considerably reduced or even eliminated altogether.
  • the surface of the fins is used throughout the cut and ensures a very good efficiency in energy transfer. It should be noted that the flat surfaces of the fins are used more to absorb the heat of the gases emitted, than to interact directly with the arc. More precisely, the arc does not seem to be divided into a multiplicity of arcs stretching in series between adjacent fins.
  • the fins have a given thickness and are separated in pairs by a given distance which is of the same order of magnitude as said thickness.
  • the small distance between fins promotes the heat exchange between the gases and the fins, especially in the phase where the arc is located in the chimney.
  • the distance between fins will be between 0.8 and 3 mm, and it will be between half and twice the thickness of the fins.
  • the distance between two fins here designates the smallest distance measured between the two fins, especially when the fins are not parallel to each other. It will be noted that it is the architecture of the circuit breaker, and in particular the presence of the corridor favoring the insertion of the electric arc, which makes it possible to arrange the fins at a short distance from one another.
  • the space between fins is always greater than at least 20% to the thickness of the fins, while one can authorize according to the invention much lower distances.
  • the chimney is limited posteriorly by the posterior wall. This arrangement promotes the constriction of the foot of the arc, the rise in voltage of the arc and the limitation of the pressure in the chamber.
  • the rear wall is devoid of gas evacuation orifice. This promotes the flow of gas between the fins, so the use of the entire surface of the fins as heat exchange surface.
  • the chamber and the opening volume together form a closed cutoff volume.
  • the arrangement of the chamber makes it possible to control the rise in pressure, and thus to close the chamber, without major risk of explosion of the apparatus.
  • the lower longitudinal electrode is separated from the fins by a distance that is of the same order of magnitude as the thickness of the fins.
  • This arrangement allows a significant constriction of the foot of the arc.
  • the lateral volume between the bottom wall and the fins, on at least one of the sides of the lower electrode, is limited by walls which also contribute to the constriction of the arc.
  • each fin is provided with at least one lateral fastening tab, retained in a slot of one of the side walls, and at least one posterior fixing tab, retained in a slot of the posterior wall.
  • the posterior tongue answers the problem of fixing the fin, and makes it possible to compensate for the possible mechanical weakness due to the presence of the chimney.
  • the fins are parallel to each other.
  • the rear wall is inclined relative to the fins. This arrangement tends to stabilize the arc at the bottom of 1 chamber and increase the length of the arc.
  • the corridor extends substantially in the reference geometric plane equidistant from the side walls of the chamber. This arrangement will be preferred for high performance and when it is desired to avoid too rapid alteration of the side walls of the chamber.
  • the corridor is indeed a privileged way for the arc which is thus centered as it moves towards the chimney.
  • the narrow intermediate portion of the corridor approaches one of the side walls away from the opening volume.
  • the contacts are in a median plane of the chamber, midway between the side walls of the chamber, which optimizes the opening volume.
  • the corridor sinks obliquely into the room.
  • the narrowest fins are used mainly for their constrictor effect when inserting the bow.
  • the wider fins are also used for cooling the gas once the arc is installed in the chimney.
  • the apparatus is a limiting circuit breaker comprising rigid conductors for supplying the current to the contacts, these rigid conductors having a shape such that when they are traversed by a current, they generate an intense electromagnetic field near the contacts, clean to cause electromagnetic repulsion of the movable contact towards the separation position and to project the electric arc into the chamber.
  • the fixed contact will be supported by a U-shaped conductor.
  • Other forms amply described in the state of the art are however possible. The projection of the arc allows it to reach the chimney quickly.
  • a molded-case power low-voltage limiting circuit breaker has one or more breaking poles.
  • the pole 10 represented on the figure 1 comprises a molded plastic housing 12, inside which is housed a rotary contact bridge 14, carried by a shaft section 16 extending perpendicular to the plane of the figure 1
  • the shaft 16 is driven by a drive mechanism known per se, as described for example in the document FR 2,589,624 .
  • the contact bridge 14 comprises a first movable contact 18 cooperating with a first fixed contact 20, and a second movable contact 22 cooperating with a second fixed contact 24.
  • To each pair of contacts 18, 20, resp. 22, 24 is associated an arc extinguishing chamber 26, resp. 28.
  • the construction of the pole 10 being symmetrical with respect to the axis of rotation 30 of the switching shaft 16, it will suffice to describe in detail the half of the pole associated with the contacts 18, 20 and the chamber 26.
  • the fixed contact 20 is fixed on a contact member 32 constituted by a U-shaped metal part, one end of which is connected to a connection pad 34, and the other end forms a lower electrode 36 extending inside the socket. bedroom.
  • the contact 18 is movable between a separation position represented on the figure 1 and a position of contact with the fixed contact 20.
  • the separation movement of the contact 18 is a plane movement, in the sense that the path of the contact is parallel to the plane II of section of the figure 1 .
  • the path covered by the movable contact 18 between its two extreme positions defines an opening volume 38 which is closed, on the opposite side to the arc extinguishing chamber 26, by the shaft section 16, and laterally restricted by partitioning pieces 40.
  • the arc extinguishing chamber 26 is delimited by a rear wall 42 opposite to the opening volume 38, a bottom wall 48 and an upper wall 50, constituted by walls of the housing, as well as two flat lateral walls 44, 46. , constituted by plates of insulating material plated on a wall of the housing.
  • the chamber 26 opens on the opening volume 38.
  • the breaking volume 52 constituted by the arc extinguishing chamber 26 and the opening volume 38 is closed, in the sense that it is not provided. channel or exhaust port voluntary cutoff gases. By cons, no special provision is made to avoid possible leakage by the joining lines of the various parts of the molded housing.
  • the breaking volume 52 is therefore a sealed volume, the sealing is however imperfect.
  • the seal is similar to that defined by the code Ip54 according to IEC 60529: "volume protected against splashing water in all directions and against dust (no harmful deposit)”.
  • the chamber contains flat metal fins 54 arranged parallel to each other and perpendicular to the side walls 44, 46.
  • the gap between two fins is small, of the order of the thickness of the fins.
  • Each fin is provided with two lateral tabs 55a for positioning and retention, embedded in the side walls 44,46, and two rear tabs 55b.
  • Each fin has its rear rim fully inserted in a groove of the rear wall to prevent gas flow, and the rear tabs 55b are embedded in force in deeper recesses of the rear wall to provide mechanical strength.
  • the side edges of the fins are pressed against the side walls, so as not to leave significant clearance between walls and fins.
  • the lower wall 48 of the chamber has a groove 56 in which is embedded the lower electrode 36, as shown in detail in FIG. figure 3 .
  • the flanges 58 of the groove protrude, relative to the electrode 36, towards the inside of the chamber 26.
  • the bottom wall 48 is raised so as to reduce the space separating the wall lower 48 of the fin 54 nearest.
  • the distance between the lower electrode 36 and the nearest fin is of the same order of magnitude as the gap between two fins.
  • the electrode 36 formed by the fixed contact member 32 has an end portion disposed substantially parallel to the fins, perpendicular to the III-III sectional plane inside the chamber, and an intermediate portion disposed substantially perpendicular to the reference direction 60.
  • the posterior wall 42 is in turn inclined with respect to the reference direction 60, but also with respect to a III-III section plane. The inclination of the posterior wall 42 is intermediate between the direction 60 and the plane III-III.
  • the chamber also comprises in its upper part an upper electrode 62 embedded covers a large part of the upper wall 50.
  • the upper electrode is not electrically connected to one of the contact.
  • the fins 54 have an edge 68 forming a cutout defining two wings on either side of a passage 70.
  • the passage extends in height from the lower wall 48 and the lower electrode 36, to the wall upper 50 and the upper electrode 62.
  • the corridor 70 has a flared front portion 70a facing the contacts. It comprises a narrow longitudinal portion 70b followed by an enlargement on the opposite side of the contacts, near the rear wall of the chamber, forming a chimney 70c between the lower wall 48 and the lower electrode 36 on the one hand, and the upper wall 50 and the upper electrode 62 on the other hand.
  • the lower electrode 36 and the upper electrode 62 - or the upper wall 50, if the upper electrode is absent - are thus directly opposite one another on either side of the corridor.
  • the chimney 70c is oblong, that is to say that its width, measured in a direction perpendicular to the median longitudinal geometric plane is greater than its depth, measured in a cutting plane parallel to any of the fins 54.
  • the chimney 70c is inclined substantially parallel to the rear wall, in a direction 63.
  • the apparatus operates in the following manner.
  • the electromagnetic field induced by the current flowing in the conductors and in particular in the U-shaped fixed contact member 32 generates in the moving contact member 14 electrodynamic forces which repel violently.
  • the movable contact in separation position, this movement being subsequently confirmed by the opening of the drive mechanism of the shaft 16.
  • an electric arc arises between the contacts 18, 20.
  • This arc is projected into the chamber by the electrodynamic forces induced by the electromagnetic field.
  • the arc remains halfway between the side walls 44, 46, since it tends to take the passage 70b open between the fins.
  • Gaseous convection is established from the posterior wall 42 to the prechamber 38 along the side walls 44, 46 of the chamber, so that the progression of the arc towards the posterior wall 42 is not impeded by an increase in pressure.
  • the foot of the arc migrates rapidly along the lower electrode 36 to the stack 70c, even before the movable contact 18 has reached its final separation position.
  • the foot of the arc attacks the edges 58 of the groove 56 which generate gas, causing a constriction of the foot of the arc.
  • the free space between the bottom wall 48 and the fins 54 is small, so that the lower part of the plasma column constituting the arc is confined between the lower electrode and the nearest fin, which further favors the constriction of the bow.
  • the head of the arc remains at first at the projecting end of the movable contact member 14. Due to the inclination of the fins 54, the arc embraces from the beginning of the opening a large number of fins, which is favorable to a significant heat exchange.
  • the foot of the arc is at the end of the lower electrode 36, at the bottom of the chimney 70c.
  • the arc is curved further up the chimney 70c of the end of the lower electrode 36 at the end of the upper electrode 62, then along the upper electrode 62 which constitutes an equipotential surface to reach the projecting end of the movable contact member 14 in the separation position.
  • the arc divides even into two arcs in series: a long arc between the lower electrode 36 and the upper electrode 62 and a short arc between the upper electrode 62 and the movable contact member 14. In this case, the head of the longbow migrates almost instantly to the bottom of the chamber.
  • the arc is installed stably in the chimney 70c until it goes out.
  • This position of the arc promotes a lateral circulation of the gas in the chamber, from the chimney to the opening volume, that is to say a flow between the fins 54, along the side walls 44, 46.
  • the gas cools rapidly by exchange with the fins and the side walls of the chamber and contracts.
  • the gas finds no exhaust out of the breaking volume 52.
  • the fins 54 provide the arc with a heat exchange surface during the entire cut, especially in their part near the edges 68.
  • the bow both as it progresses in the room and when it is installed in the room. chimney 70c, tends to expand to invade all available space.
  • the fins 54 contain this expansion by interacting with the periphery of the arc.
  • the arc voltage increases as the arc cools and the pressure increases in the breaking volume, which eventually allows the arc to go out when the current passes through zero.
  • the narrow middle portion 70b of the passage 70 promotes the migration of the arc to the bottom of the chamber, and the chimney 70c stabilizes the arc in this region.
  • the comparative tests show that if you practice a chimney at the bottom of the room without intermediate corridor, the arc does not always reach the chimney, and that inversely, if one has a corridor without chimney, the bow does not install at the bottom of the hallway so that there is repetitive arc reclining between the contacts. It is therefore the conjunction of the narrow intermediate portion 70b of the corridor and the chimney 70c which allows to quickly and sustainably move the arc contacts.
  • FIG 5 illustrates a second embodiment of the invention, wherein each of the planar fins of the first embodiment is replaced by two lateral wings 154a, 154b. Each lateral wing is then provided with a recess tongue in the rear wall and a tongue recess in the side wall. This variant simplifies the manufacture of the fins, and possibly allows a mounting fins staggered.
  • a third embodiment of the invention, illustrated on the figure 6 was therefore developed specifically for a narrow-width apparatus with a narrow arc extinction chamber.
  • the corridor 270 runs directly along one of the side walls 246 and is delimited on the opposite lateral side by fins 254, pressed against the side wall 244.
  • the width of the fins, measured between the passage 270 and the wall 244, is then sufficient to that the side walls do not significantly impede the penetration of gas between the fins 254.
  • the tests show that the gases penetrate well between the fins 254 and cool there.
  • the direct exposure of the wall 246 to the arc makes this device difficult to control and requires a non-gasogenic wall and good heat capacity, for example porous ceramic.
  • a fourth embodiment of the invention is illustrated on the figure 7 and solves this residual problem.
  • reference signs used in the first embodiment have been used as far as possible for parts corresponding to similar parts of the first embodiment. embodiment, increased by 300.
  • a median plane 302 of the chamber located midway from the side walls 344, 346 of the chamber.
  • the contacts 318 are located laterally offset from the median plane 302.
  • the separators 354 are cut to define a corridor 370 having a mouth 370a, a middle portion 370b and a chimney 370c.
  • the middle part 370b extends obliquely with respect to the median plane.
  • the corridor 370 approaches one of the side walls away from the opening volume 338. Between the middle portion of the corridor 370b and the wall 344, the fins have a small width, while the other side of the corridor 370b, the width of the fins is greater. This phenomenon is accentuated by approaching the bottom of the room.
  • the chimney 370c is constituted in this embodiment by an elbow of the corridor. The insertion of the arc in the corridor 370 is not impeded by the particular arrangement of the corridor, because it remains in a radial plane with respect to the reference geometric axis.
  • the side walls 344, 346 of the chamber are sufficiently protected from the arc due to the interposition of the fins 354, even on the side where they are narrower.
  • the arc is installed in the chimney 370c and remains there.
  • the gases emitted at the periphery of the arc then find between the passage 370b and the wall 346 wide fins which provide efficient cooling and which also allow sufficient flow.
  • This arrangement offers the advantage over the embodiment of the figure 6 , to protect the side wall 344 of the chamber located on the narrow fins side, without impeding the flow of gas.
  • the upper electrode may be omitted in some cases.
  • the fins are preferably parallel to each other, which promotes a uniform flow of gas and a continuous exchange with the entire surface of the fins.
  • other provisions may be considered.
  • the angle of inclination of the fins relative to the reference direction may be greater or less, between 0 and 90 °, typically between 30 and 60 °. It can be seen that a strong inclination favors the rise in tension of the arc at the beginning of the opening, probably because at the beginning of the opening, the foot of the arc is rapidly projected towards the free end of the electrode by the electromagnetic effect of the contact member U, so that the arc is itself inclined and can embrace a greater number of fins if they are themselves same inclined.
  • the flow of gas laterally from the chimney to the prechamber can be promoted by the establishment of intermediate insulating partitions parallel to the side walls and delimiting with them lateral channels on either side of the median corridor.
  • the invention applies both to the double-break pole, having a movable contact bridge and two breaking chambers per pole, to a pole having only one arc extinction chamber per pole.
  • the movable contact may be rotatable or movable in translation.
  • the fixed contact 20 may be replaced by a movable contact, driven by the driving mechanism of the contacts in opposition with the contact 22, or by a semi-moving contact, driven by a contact pressure spring.
  • the invention although it finds its prime application in sealed extinguishing chambers, is also applicable to arc extinguishing chambers provided with a gas evacuation port. In this case, it seems preferable to avoid any escape near the bottom of the chimney and the lower electrode. An exhaust from the top of the chimney, near the upper electrode or through holes in the upper electrode is possible.

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  • Arc-Extinguishing Devices That Are Switches (AREA)

Description

DOMAINE TECHNIQUE DE L'INVENTIONTECHNICAL FIELD OF THE INVENTION

L'invention est relative à un appareillage électrique de coupure, en particulier un appareillage limiteur tel qu'un disjoncteur limiteur, dont les manifestations extérieures lors de la coupure sont réduites, voire inexistantes.The invention relates to an electrical switchgear, in particular a limiting device such as a limiting circuit breaker, whose external manifestations during the cut are reduced or nonexistent.

ETAT DE LA TECHNIQUESTATE OF THE ART

Dans le document FR 2 589 624 est décrite une chambre d'extinction d'arc conventionnelle pour disjoncteur électrique basse tension de puissance. La chambre est située en regard des contacts séparables du disjoncteur, et pourvue d'orifices d'évacuation des gaz sur une paroi postérieure opposée aux contacts. Des ailettes métalliques planes sont disposées à l'intérieur de la chambre, entre les contacts et l'orifice d'évacuation des gaz, perpendiculairement aux parois latérales. En cas de court-circuit, la séparation des contacts provoque un arc électrique qui est projeté dans la chambre par un effet de boucle électromagnétique. En progressant dans la chambre, l'arc rencontre les ailettes qui absorbent une partie de son énergie. L'arc échange également avec les parois latérales de la chambre, qui sont en matériau synthétique gazogène. L'arc se refroidit progressivement et sa tension monte de sorte que lors du passage du courant par zéro, l'arc s'éteint définitivement. Les effets thermiques et cinétiques du plasma d'arc pendant la coupure provoquent une brusque augmentation de la pression dans la chambre d'extinction. Les orifices d'évacuation permettent d'évacuer les gaz émis et de contenir la pression à un niveau acceptable à l'intérieur du boîtier de l'appareil. Cette évacuation des gaz de coupure partiellement ionisés impose toutefois des distances minimales de sécurité entre appareils sur un même tableau électrique, afin d'éviter tout risque d'amorçage entre pièces voisines sous tension. Elle impose également que des dispositions soient prises pour que les surpressions n'endommagent pas le tableau lui-même. De plus, les gaz évacués peuvent être considérés comme polluants et doivent de ce fait être filtrés.In the document FR 2,589,624 is described a conventional arc extinguishing chamber for electric circuit breaker low voltage power. The chamber is located opposite the separable contacts of the circuit breaker, and provided with gas evacuation ports on a rear wall opposite the contacts. Flat metal fins are disposed within the chamber, between the contacts and the gas discharge port, perpendicular to the side walls. In the event of a short circuit, the separation of the contacts causes an electric arc that is projected into the chamber by an electromagnetic loop effect. Progressing in the room, the bow meets the fins that absorb some of its energy. The arc also exchanges with the side walls of the chamber, which are made of synthetic gas-forming material. The arc cools gradually and its voltage rises so that when the current passes through zero, the arc goes off permanently. The thermal and kinetic effects of the arc plasma during the cutoff cause a sudden increase in the pressure in the extinguishing chamber. The exhaust ports allow the exhaust gas to escape and contain the pressure at an acceptable level within the housing of the unit. This evacuation of partially ionized cutoff gas imposes, however, minimum distances of safety between devices on the same electrical panel, to avoid any risk of ignition between neighboring parts under tension. It also requires that arrangements be made for overpressure not to damage the painting itself. In addition, exhaust gases can be considered as pollutants and must therefore be filtered.

On connaît par ailleurs des appareillages électriques de coupure dont le boîtier est étanche, de manière à éliminer toute manifestation extérieure lors de la coupure, comme décrit par exemple dans le document GB 2 119 575 . Il est alors nécessaire de pourvoir le boîtier de dispositifs d'étanchéité performants et de renforcer sa tenue mécanique à la pression. L'étanchéité est obtenue au prix d'une diminution des performances de coupure par rapport à un appareillage conventionnel de même volume. De plus, le coût de tels appareils par rapport aux appareils conventionnels est très élevé, de sorte qu'ils ne sont mis en oeuvre que dans des conditions extrêmes, par exemple dans des environnements explosifs.Electrical switching devices are also known whose housing is sealed, so as to eliminate any external manifestation during the cut, such as described for example in the document GB 2,119,575 . It is then necessary to provide the housing with high performance sealing devices and to reinforce its mechanical resistance to pressure. Sealing is obtained at the cost of a reduction in cut-off performance compared to conventional equipment of the same volume. In addition, the cost of such devices compared to conventional devices is very high, so they are implemented only under extreme conditions, for example in explosive environments.

Un disjoncteur basse tension de puissance étanche est décrit dans le document WO95/08832 . Ce disjoncteur comporte une chambre d'extinction d'arc disposée en regard des contacts et pourvue d'ailettes de refroidissement qui sont disposées entre les contacts et une ouverture de sortie de la chambre. Un canal de recirculation dirige les gaz de la sortie de la chambre vers le mécanisme d'entraînement des contacts, en passant par un filtre de désionisation. Les gaz émis lors de la coupure au niveau de la chambre d'extinction d'arc s'écoulent ainsi en circuit fermé dans le boîtier et sont finalement redirigés vers les contacts et vers l'entrée de la chambre, après avoir été refroidis et désionisé. Cette convection importante favorise un déplacement rapide de l'arc à l'intérieur de la chambre, ce qui est considéré dans ce document comme particulièrement avantageux pour accélérer la coupure. L'arc en effet, en se déplaçant dans la chambre, rencontre constamment de nouvelles surfaces froides qui assurent son refroidissement. Toutefois, la taille de la chambre nécessaire pour atteindre des performances de coupure élevées s'en trouve accrue car la capacité d'absorption énergétique des ailettes n'est pas pleinement exploitée du fait de la rapide avancée de l'arc. De plus, le canal de recirculation rend le boîtier plus encombrant et plus complexe. Enfin, il n'est pas exclu que l'arc quitte totalement la chambre par l'ouverture de sortie, du fait de la forte convection. Dans ce cas, l'arc n'est plus en contact avec les ailettes et n'est plus refroidi.A low-voltage circuit breaker with sealed power is described in the document WO95 / 08832 . This circuit breaker comprises an arc extinction chamber disposed opposite the contacts and provided with cooling fins which are arranged between the contacts and an outlet opening of the chamber. A recirculation channel directs gases from the chamber outlet to the drive mechanism of the contacts through a deionization filter. The gases emitted during the breaking at the arc extinguishing chamber thus flow in closed circuit in the housing and are finally redirected to the contacts and to the chamber inlet, after having been cooled and deionized . This important convection promotes rapid movement of the arc inside the chamber, which is considered in this document as particularly advantageous for accelerating the cut. The bow, in fact, moving in the room, constantly encounters new cold surfaces that ensure its cooling. However, the size of the chamber necessary to achieve high breaking performance is increased because the energy absorption capacity of the fins is not fully exploited because of the rapid advance of the arc. In addition, the recirculation channel makes the housing more cumbersome and more complex. Finally, it is not excluded that the arc completely leaves the room through the exit opening, because of the strong convection. In this case, the arc is no longer in contact with the fins and is no longer cooled.

Pour mieux utiliser la surface d'échange offerte par les ailettes de refroidissement et éviter que l'arc ne quitte la chambre d'extinction, il a été proposé, dans le document DE 24 10 049 , de disposer les ailettes dans une enveloppe en matériau gazogène, dont une paroi opposée au contacts est pourvue de fentes d'évacuation des gaz, et d'adapter à l'extérieur de l'enveloppe, plaqué contre la paroi comportant les fentes, un masque comportant des trous de faible diamètre. Les ailettes sont découpées en V de manière à former une fente d'attaque. Lorsque le disjoncteur s'ouvre sur un courant de court-circuit, l'arc pénètre dans la chambre de manière centrée. Arrivé au fond de la chambre, l'arc est dévié sur l'un ou l'autre des côtés et retourne vers les contacts en se divisant entre les ailettes, puis est rétabli entre les contacts avant d'être de nouveau projeté dans la chambre. Le pied de l'arc suit donc une trajectoire en boucle jusqu'à ce que l'énergie d'arc ait été dissipée dans les ailettes. Les ailettes sont ainsi utilisées de manière homogène. Toutefois, la circulation de l'arc donne lieu à des réamorçages périodique de l'arc sur les contacts, qui endommagent les contacts.In order to make better use of the exchange surface provided by the cooling fins and to prevent the arc from leaving the extinguishing chamber, it has been proposed in the document DE 24 10 049 , arranging the fins in an envelope of gas-generating material, a wall opposite the contacts of which is provided with gas evacuation slots, and adapted to the outside of the casing, pressed against the wall comprising the slots, a mask with small diameter holes. The fins are cut in a V shape to form a slot attack. When the circuit breaker opens to a short-circuit current, the arc enters the chamber centrally. At the bottom of the chamber, the arc is deflected on one or the other side and returns to the contacts by dividing between the fins, then is restored between the contacts before being projected again in the room . The foot of the arc follows a loop path until the arc energy has been dissipated in the fins. The fins are thus used homogeneously. However, the circulation of the arc gives rise to periodic rebooting of the arc on the contacts, which damage the contacts.

Dans le document DE 26 24 957 sont décrits des plaques d'extinction d'arc destinées à une chambre d'extinction d'arc d'un appareillage électrique de coupure. Les plaques ont une découpe formant une encolure évasée en U ou en V prolongée par une fente s'ouvrant sur un élargissement circulaire. Cette forme est sensée assurer une bonne localisation de l'arc et son extinction rapide. Il est prévu de recouvrir les plaques d'extinction d'un matériau isolant, plastique ou céramique, notamment du polytétrafluoroéthylène, de manière à stabiliser le positionnement de l'arc dans la partie circulaire élargie. Les plaques peuvent être constituées en fer doux et recouvertes, au niveau de la partie circulaire élargie au moins, d'un matériau magnétique doux et isolant électrique, pour empêcher l'arc de former un pied sur le pourtour de l'élargissement. Suivant cet enseignement, l'arc peut être localisé dans la partie élargie circulaire, mais rien n'est prévu pour assurer son extinction. En particulier, les dispositions prises pour stabiliser l'arc et empêcher la formation d'un pied d'arc ont pour conséquence que l'échange énergétique entre l'arc et son environnement est très réduit. Apparemment, l'arc ne peut effectivement échanger qu'avec les arêtes des plaques, au niveau de l'élargissement circulaire. La partie latérale des plaques n'est donc pas utilisée de façon efficace pour le refroidissement de l'arc. Enfin, le traitement des plaques en plusieurs couches de matériaux différents augmente considérablement le coût du dispositif.In the document DE 26 24 957 arc extinguishing plates are described for an arc extinguishing chamber of an electrical switchgear. The plates have a cut forming a flared neck in U or V extended by a slot opening on a circular widening. This shape is supposed to ensure a good location of the arc and its rapid extinction. It is intended to cover the extinguishing plates with an insulating material, plastic or ceramic, including polytetrafluoroethylene, so as to stabilize the positioning of the arc in the enlarged circular portion. The plates may be made of soft iron and covered, at least in the circular enlarged portion, with a soft, magnetic electrical insulating material to prevent the arc from forming a foot on the periphery of the widening. According to this teaching, the arc can be located in the widened circular part, but nothing is planned to ensure its extinction. In particular, the arrangements made to stabilize the arc and prevent the formation of a foot arc result in the energy exchange between the arc and its environment is very small. Apparently, the arc can only exchange with the edges of the plates, at the level of the circular widening. The lateral part of the plates is therefore not used effectively for the cooling of the arc. Finally, the treatment of the plates in several layers of different materials considerably increases the cost of the device.

EXPOSE DE L'INVENTIONSUMMARY OF THE INVENTION

L'invention vise donc à remédier aux inconvénients de l'état de la technique, de manière à proposer, dans un volume réduit, un appareillage de coupure performant et aux manifestations extérieures fortement diminuées.The invention therefore aims to overcome the drawbacks of the state of the art, so as to propose, in a reduced volume, a cutting apparatus performance and external manifestations greatly reduced.

Selon l'invention, ce problème est résolu grâce à un appareillage électrique de coupure, comportant :

  • un boîtier définissant un plan géométrique longitudinal de référence, et délimitant :
    • un volume d'ouverture et
    • une chambre d'extinction d'arc s'ouvrant sur le volume d'ouverture et délimitée par deux parois latérales opposées parallèles au plan géométrique de référence, une paroi postérieure éloignée du volume d'ouverture, une paroi inférieure et une paroi supérieure ;
  • une paire de contacts séparables disposée dans le volume d'ouverture et comportant un premier contact mobile suivant une trajectoire plane dans le plan géométrique de référence, entre une position de contact et une position de séparation et un deuxième contact ;
  • des ailettes de refroidissement disposées à l'intérieur de la chambre d'extinction d'arc, perpendiculairement au plan géométrique de référence, chaque ailette ayant une arête libre d'attaque exposée à l'arc ;
  • une électrode longitudinale inférieure en liaison électrique avec 1e deuxième contact, l'électrode inférieure couvrant au moins partiellement la paroi inférieure de la chambre ;
dans lequel :
  • les arêtes libres délimitent latéralement un couloir s'étendant en hauteur de l'électrode inférieure à la paroi supérieure, le couloir ayant :
    • une première extrémité longitudinale évasée débouchant sur le volume d'ouverture
    • une deuxième extrémité longitudinale élargie formant une cheminée à proximité de la paroi postérieure, la cheminée ayant section oblongue dans un plan de section parallèle aux ailettes,
    • une portion intermédiaire étroite reliant la première extrémité longitudinale à la cheminée, l'électrode inférieure s'étendant longitudinalement dans le couloir du deuxième contact jusqu'à la cheminée au moins.
According to the invention, this problem is solved by means of electrical switchgear, comprising:
  • a housing defining a reference longitudinal geometric plane, and delimiting:
    • an opening volume and
    • an arc extinction chamber opening on the opening volume and delimited by two opposite side walls parallel to the reference geometric plane, a rear wall remote from the opening volume, a bottom wall and an upper wall;
  • a pair of separable contacts disposed in the opening volume and having a first movable contact along a plane path in the reference geometrical plane between a contact position and a separation position and a second contact;
  • cooling fins disposed within the arc extinguishing chamber, perpendicular to the geometric reference plane, each fin having a free edge of attack exposed to the arc;
  • a lower longitudinal electrode in electrical connection with the second contact, the lower electrode at least partially covering the bottom wall of the chamber;
in which :
  • the free edges delimit laterally a corridor extending in height from the lower electrode to the upper wall, the corridor having:
    • a first flared longitudinal end opening on the opening volume
    • an enlarged second longitudinal end forming a chimney close to the rear wall, the chimney having an oblong section in a section plane parallel to the fins,
    • a narrow intermediate portion connecting the first longitudinal end to the chimney, the lower electrode extending longitudinally in the corridor of the second contact to the chimney at least.

. Le couloir et la cheminée permettent à l'arc de s'installer rapidement et de manière stable au fond de la chambre, dans la zone qui en section présente une forme oblongue. On sait que l'arc tend naturellement en milieu ouvert à prendre une forme générale cylindrique de section circulaire. La forme oblongue de la cheminée contribue donc à une forte constriction de l'arc, d'où un échange énergétique important avec les ailettes et les parois à ce niveau. Un courant gazeux de convection s'établit entre les ailettes, latéralement par rapport au couloir, et permet un refroidissement et une désionisation des gaz au contact des ailettes, jusqu'à extinction de l'arc. Ce refroidissement rapide des gaz limite considérablement la montée en pression dans la chambre. Les manifestations extérieures s'en trouvent considérablement réduites, voire totalement éliminées. La surface des ailettes est utilisée pendant toute la coupure et assure un très bon rendement dans le transfert énergétique. Il est à souligner que les surfaces planes des ailettes sont utilisées plus pour absorber la chaleur des gaz émis, que pour interagir directement avec l'arc. Plus précisément, l'arc ne semble pas se diviser en une multiplicité d'arcs s'étirant en série entre ailettes adjacentes. . The corridor and the chimney allow the bow to settle quickly and stably at the bottom of the chamber, in the area in section has an oblong shape. It is known that the arc naturally tends in an open environment to assume a generally circular cylindrical shape. The oblong shape of the chimney thus contributes to a strong constriction of the arc, hence a significant energy exchange with the fins and the walls at this level. A convective gas stream is established between the fins, laterally with respect to the corridor, and allows cooling and deionization of the gases in contact with the fins, until the arc is extinguished. This rapid cooling of the gases considerably limits the rise in pressure in the chamber. External manifestations are considerably reduced or even eliminated altogether. The surface of the fins is used throughout the cut and ensures a very good efficiency in energy transfer. It should be noted that the flat surfaces of the fins are used more to absorb the heat of the gases emitted, than to interact directly with the arc. More precisely, the arc does not seem to be divided into a multiplicity of arcs stretching in series between adjacent fins.

Préférentiellement, les ailettes ont une épaisseur donnée et sont séparées deux à deux par une distance donnée qui est du même ordre de grandeur que ladite épaisseur. L'expérience montre que la faible distance entre ailettes favorise l'échange thermique entre les gaz et les ailettes, notamment dans la phase où l'arc se trouve localisé dans la cheminée. A titre indicatif, la distance entre ailettes sera comprise entre 0,8 et 3 mm, et elle sera comprise entre la moitié et le double de l'épaisseur des ailettes. La distance entre deux ailettes désigne ici la plus petite distance mesurée entre les deux ailettes, notamment lorsque les ailettes ne sont pas parallèles entre elles. On notera que c'est l'architecture du disjoncteur, et notamment la présence du couloir favorisant l'insertion de l'arc électrique, qui permet de disposer les ailettes à faible distance les unes des autres. Classiquement dans l'état de la technique, l'espace entre ailettes est toujours supérieur d'au moins 20% à l'épaisseur des ailettes, alors que l'on peut s'autoriser selon l'invention des distance nettement inférieures.Preferably, the fins have a given thickness and are separated in pairs by a given distance which is of the same order of magnitude as said thickness. Experience shows that the small distance between fins promotes the heat exchange between the gases and the fins, especially in the phase where the arc is located in the chimney. As an indication, the distance between fins will be between 0.8 and 3 mm, and it will be between half and twice the thickness of the fins. The distance between two fins here designates the smallest distance measured between the two fins, especially when the fins are not parallel to each other. It will be noted that it is the architecture of the circuit breaker, and in particular the presence of the corridor favoring the insertion of the electric arc, which makes it possible to arrange the fins at a short distance from one another. Conventionally in the state of the art, the space between fins is always greater than at least 20% to the thickness of the fins, while one can authorize according to the invention much lower distances.

Préférentiellement, la cheminée est limitée postérieurement par la paroi postérieure. Cette disposition favorise la constriction du pied de l'arc, la montée en tension de l'arc et la limitation de la pression dans la chambre.Preferably, the chimney is limited posteriorly by the posterior wall. This arrangement promotes the constriction of the foot of the arc, the rise in voltage of the arc and the limitation of the pressure in the chamber.

Préférentiellement, la paroi postérieure est dépourvue d'orifice d'évacuation de gaz. On favorise ainsi la circulation des gaz entre les ailettes, donc l'utilisation de toute la surface des ailettes comme surface d'échange thermique.Preferably, the rear wall is devoid of gas evacuation orifice. This promotes the flow of gas between the fins, so the use of the entire surface of the fins as heat exchange surface.

Selon un mode de réalisation particulièrement avantageux, la chambre et le volume d'ouverture forment ensemble un volume de coupure clos. La disposition de la chambre permet de maîtriser la montée en pression, et donc de clore la chambre, sans risque majeur d'explosion de l'appareil. Alternativement, et pour les appareils de volume très réduit, il pourra être préférable de prévoir au moins un orifice d'évacuation calibré ou une soupape de surpression, pour limiter la surpression dans la chambre.According to a particularly advantageous embodiment, the chamber and the opening volume together form a closed cutoff volume. The arrangement of the chamber makes it possible to control the rise in pressure, and thus to close the chamber, without major risk of explosion of the apparatus. Alternatively, and for devices of very small volume, it may be preferable to provide at least one calibrated discharge orifice or a pressure relief valve, to limit the overpressure in the chamber.

Selon un mode de réalisation, l'électrode longitudinale inférieure est séparée des ailettes par une distance qui est du même ordre de grandeur que l'épaisseur des ailettes. Cette disposition permet une constriction importante du pied de l'arc. Préférentiellement, le volume latéral entre la paroi inférieure et les ailettes, sur au moins l'un des côtés de l'électrode inférieure, est limité par des parois qui contribuent également à la constriction de l'arc.According to one embodiment, the lower longitudinal electrode is separated from the fins by a distance that is of the same order of magnitude as the thickness of the fins. This arrangement allows a significant constriction of the foot of the arc. Preferably, the lateral volume between the bottom wall and the fins, on at least one of the sides of the lower electrode, is limited by walls which also contribute to the constriction of the arc.

Préférentiellement chaque ailette est munie d'au moins une languette latérale de fixation, retenue dans une fente d'une des parois latérales, et d'au moins une languette postérieure de fixation, retenue dans une fente de la paroi postérieure. La languette postérieure répond au problème de fixation de l'ailette, et permet de compenser l'éventuelle faiblesse mécanique due à la présence de la cheminée.Preferably each fin is provided with at least one lateral fastening tab, retained in a slot of one of the side walls, and at least one posterior fixing tab, retained in a slot of the posterior wall. The posterior tongue answers the problem of fixing the fin, and makes it possible to compensate for the possible mechanical weakness due to the presence of the chimney.

Selon un mode de réalisation, les ailettes sont parallèles entre elles.According to one embodiment, the fins are parallel to each other.

Selon un mode de réalisation de l'invention, la paroi postérieure est inclinée par rapport aux ailettes. Cette disposition tend à stabiliser l'arc au fond de 1 chambre et à accroître la longueur de l'arc.According to one embodiment of the invention, the rear wall is inclined relative to the fins. This arrangement tends to stabilize the arc at the bottom of 1 chamber and increase the length of the arc.

Selon un mode de réalisation de l'invention, le couloir s'étend sensiblement dans le plan géométrique de référence, à égale distance des parois latérales de la chambre . Cette disposition sera préférée pour les performances élevées et lorsque l'on souhaitera éviter une altération trop rapide des parois latérales de la chambre. Le couloir constitue en effet une voie privilégiée pour l'arc qui se trouve ainsi centré lors de son déplacement vers la cheminée.According to one embodiment of the invention, the corridor extends substantially in the reference geometric plane equidistant from the side walls of the chamber. This arrangement will be preferred for high performance and when it is desired to avoid too rapid alteration of the side walls of the chamber. The corridor is indeed a privileged way for the arc which is thus centered as it moves towards the chimney.

Suivant une autre alternative, la partie intermédiaire étroite du couloir se rapproche d'une des parois latérales en s'éloignant du volume d'ouverture. Cette disposition constitue un compromis intéressant pour optimiser les dimensions de la chambre. Les contacts se trouvent dans un plan médian de la chambre, à mi-distance entre les parois latérales de la chambre, ce qui permet d'optimiser le volume d'ouverture. Le couloir s'enfonce obliquement dans la chambre. Les ailettes les plus étroites sont utilisées surtout pour leur effet constricteur lors de l'insertion de l'arc. Les ailettes les plus larges sont utilisées quant à elles également pour refroidir les gaz une fois que l'arc s'est installé dans la cheminée.According to another alternative, the narrow intermediate portion of the corridor approaches one of the side walls away from the opening volume. This arrangement is an interesting compromise to optimize the dimensions of the chamber. The contacts are in a median plane of the chamber, midway between the side walls of the chamber, which optimizes the opening volume. The corridor sinks obliquely into the room. The narrowest fins are used mainly for their constrictor effect when inserting the bow. The wider fins are also used for cooling the gas once the arc is installed in the chimney.

Préférentiellement, l'appareillage est un disjoncteur limiteur comportant des conducteurs rigides d'amenée du courant aux contacts, ces conducteurs rigides ayant une forme telle que lorsqu'ils sont parcourus par un courant, ils engendrent un champ électromagnétique intense à proximité des contacts, propre à provoquer une répulsion électromagnétique du contact mobile vers la position de séparation et à projeter l'arc électrique dans la chambre . Typiquement, le contact fixe sera supporté par un conducteur en U. D'autres formes amplement décrites dans l'état de la technique sont toutefois envisageables. La projection de l'arc permet à celui-ci d'atteindre rapidement la cheminée.Preferably, the apparatus is a limiting circuit breaker comprising rigid conductors for supplying the current to the contacts, these rigid conductors having a shape such that when they are traversed by a current, they generate an intense electromagnetic field near the contacts, clean to cause electromagnetic repulsion of the movable contact towards the separation position and to project the electric arc into the chamber. Typically, the fixed contact will be supported by a U-shaped conductor. Other forms amply described in the state of the art are however possible. The projection of the arc allows it to reach the chimney quickly.

BREVE DESCRIPTION DES FIGURESBRIEF DESCRIPTION OF THE FIGURES

D'autres avantages et caractéristiques ressortiront plus clairement de la description qui va suivre de modes particuliers de réalisation de l'invention, donnés à titre d'exemples non limitatifs, et représentés aux dessins annexés sur lesquels :

  • la figure 1 représente un appareillage selon un premier mode de réalisation de l'invention, vu en coupe suivant un plan I-I ;
  • la figure 2 représente un détail de l'appareillage de la figure 1, en coupe suivant un plan II-II ;
  • la figure 3 représente un détail de l'appareillage de la figure 1, en coupe suivant un plan III-III;
  • la figure 4 représente une ailette de l'appareillage de la figure 1 ;
  • la figure 5 représente vue schématique d'un appareillage selon un deuxième mode de réalisation de l'invention ;
  • la figure 6 représente vue schématique d'un appareillage selon un troisième mode de réalisation de l'invention ;
  • la figure 7 représente vue schématique d'un appareillage selon un quatrième mode de réalisation de l'invention.
Other advantages and features will emerge more clearly from the following description of particular embodiments of the invention, given by way of non-limiting examples, and represented in the accompanying drawings in which:
  • the figure 1 represents an apparatus according to a first embodiment of the invention, seen in section along a plane II;
  • the figure 2 represents a detail of the apparatus of the figure 1 in section along a plane II-II;
  • the figure 3 represents a detail of the apparatus of the figure 1 in section along a plane III-III;
  • the figure 4 represents a fin of the apparatus of the figure 1 ;
  • the figure 5 is a schematic view of an apparatus according to a second embodiment of the invention;
  • the figure 6 is a schematic view of an apparatus according to a third embodiment of the invention;
  • the figure 7 is a schematic view of an apparatus according to a fourth embodiment of the invention.

DESCRIPTION DETAILLEE DE DIFFERENTS MODE DE RÉALISATIONDETAILED DESCRIPTION OF DIFFERENT EMBODIMENTS

En référence aux figures 1 à 3, un disjoncteur limiteur basse tension de puissance à boîtier moulé comporte un ou plusieurs pôles de coupure. Le pôle 10 représenté sur la figure 1 comporte un boîtier en matière plastique moulée 12, à l'intérieur duquel est logé un pont de contacts rotatif 14, porté par un tronçon d'arbre 16 s'étendant perpendiculairement au plan de la figure 1 L'arbre 16 est entraîné par un mécanisme d'entraînement connu en soi, tel que décrit par exemple dans le document FR 2 589 624 . Le pont de contacts 14 comporte un premier contact mobile 18 coopérant avec un premier contact fixe 20, et un deuxième contact mobile 22 coopérant avec un deuxième contact fixe 24. A chaque paire de contacts 18, 20, resp. 22, 24 est associée une chambre d'extinction d'arc 26, resp. 28. La construction du pôle 10 étant symétrique par rapport à l'axe de rotation 30 de l'arbre de commutation 16, on se contentera de décrire en détail la moitié du pôle associée aux contacts 18, 20 et à la chambre 26.With reference to Figures 1 to 3 , a molded-case power low-voltage limiting circuit breaker has one or more breaking poles. The pole 10 represented on the figure 1 comprises a molded plastic housing 12, inside which is housed a rotary contact bridge 14, carried by a shaft section 16 extending perpendicular to the plane of the figure 1 The shaft 16 is driven by a drive mechanism known per se, as described for example in the document FR 2,589,624 . The contact bridge 14 comprises a first movable contact 18 cooperating with a first fixed contact 20, and a second movable contact 22 cooperating with a second fixed contact 24. To each pair of contacts 18, 20, resp. 22, 24 is associated an arc extinguishing chamber 26, resp. 28. The construction of the pole 10 being symmetrical with respect to the axis of rotation 30 of the switching shaft 16, it will suffice to describe in detail the half of the pole associated with the contacts 18, 20 and the chamber 26.

Le contact fixe 20 est fixé sur un organe de contact 32 constitué par une pièce métallique en U, dont une extrémité est connectée à une plage de raccordement 34, et l'autre extrémité forme une électrode inférieure 36 s'étendant à l'intérieur de la chambre.The fixed contact 20 is fixed on a contact member 32 constituted by a U-shaped metal part, one end of which is connected to a connection pad 34, and the other end forms a lower electrode 36 extending inside the socket. bedroom.

Le contact 18 est mobile entre une position de séparation représentée sur la figure 1 et une position de contact avec le contact fixe 20. Le mouvement de séparation du contact 18 est un mouvement plan, au sens où la trajectoire du contact est parallèle au plan I-I de coupe de la figure 1. La trajectoire couverte par le contact mobile 18 entre ses deux positions extrêmes définit un volume d'ouverture 38 qui est refermé, du côté opposé à la chambre d'extinction d'arc 26, par le tronçon d'arbre 16, et restreint latéralement par des pièces de cloisonnement 40.The contact 18 is movable between a separation position represented on the figure 1 and a position of contact with the fixed contact 20. The separation movement of the contact 18 is a plane movement, in the sense that the path of the contact is parallel to the plane II of section of the figure 1 . The path covered by the movable contact 18 between its two extreme positions defines an opening volume 38 which is closed, on the opposite side to the arc extinguishing chamber 26, by the shaft section 16, and laterally restricted by partitioning pieces 40.

La chambre d'extinction d'arc 26 est délimitée par une paroi postérieure 42 opposée au volume d'ouverture 38, une paroi inférieure 48 et une paroi supérieure 50, constituées par des parois du boîtier, ainsi que deux parois latérales planes 44, 46, constituées par des plaques en matériau isolant plaquées sur une paroi du boîtier. La chambre 26 s'ouvre sur le volume d'ouverture 38. Le volume de coupure 52 constitué par la chambre d'extinction d'arc 26 et par le volume d'ouverture 38 est clos, au sens où il n'est pas pourvu de canal ou d'orifice d'échappement volontaire des gaz de coupure. Par contre, aucune disposition particulière n'est prise pour éviter les fuites éventuelles par les lignes de jointures des différentes parties du boîtier moulé. Le volume de coupure 52 est donc un volume étanche, dont l'étanchéité est toutefois imparfaite. L'étanchéité doit être suffisante pour que les fuites de gaz ne perturbent pas la circulation désirée dans le volume de coupure. A titre indicatif, l'étanchéité est similaire à celle définie par le code Ip54 suivant la norme CEI 60529 : "volume protégé contre les projections d'eau dans toutes les directions et contre les poussières (pas de dépôt nuisible)".The arc extinguishing chamber 26 is delimited by a rear wall 42 opposite to the opening volume 38, a bottom wall 48 and an upper wall 50, constituted by walls of the housing, as well as two flat lateral walls 44, 46. , constituted by plates of insulating material plated on a wall of the housing. The chamber 26 opens on the opening volume 38. The breaking volume 52 constituted by the arc extinguishing chamber 26 and the opening volume 38 is closed, in the sense that it is not provided. channel or exhaust port voluntary cutoff gases. By cons, no special provision is made to avoid possible leakage by the joining lines of the various parts of the molded housing. The breaking volume 52 is therefore a sealed volume, the sealing is however imperfect. The tightness must be sufficient so that the gas leaks do not disturb the desired circulation in the breaking volume. As an indication, the seal is similar to that defined by the code Ip54 according to IEC 60529: "volume protected against splashing water in all directions and against dust (no harmful deposit)".

La chambre contient des ailettes métalliques planes 54 disposées parallèlement les unes aux autres et perpendiculairement aux parois latérales 44, 46. L'intervalle entre deux ailettes est faible, de l'ordre de l'épaisseur des ailettes. Chaque ailette est munie de deux languettes latérales 55a de positionnement et de retenue, encastrées dans les parois latérales 44,46, et de deux languettes postérieures 55b. Chaque ailette a son rebord postérieur entièrement inséré dans une rainure de la paroi postérieure pour éviter les circulations de gaz, et les languettes postérieures 55b sont encastrées en force dans des creux plus profond de la paroi postérieure pour assurer la tenue mécanique. Les rebords latéraux des ailettes sont plaqués contre les parois latérales, de manière à ne pas laisser de jeu significatif entre parois et ailettes.The chamber contains flat metal fins 54 arranged parallel to each other and perpendicular to the side walls 44, 46. The gap between two fins is small, of the order of the thickness of the fins. Each fin is provided with two lateral tabs 55a for positioning and retention, embedded in the side walls 44,46, and two rear tabs 55b. Each fin has its rear rim fully inserted in a groove of the rear wall to prevent gas flow, and the rear tabs 55b are embedded in force in deeper recesses of the rear wall to provide mechanical strength. The side edges of the fins are pressed against the side walls, so as not to leave significant clearance between walls and fins.

La paroi inférieure 48 de la chambre comporte une gorge 56 dans laquelle est encastrée l'électrode inférieure 36, comme le montre en détail la figure 3. Les rebords 58 de la gorge font saillie, par rapport à l'électrode 36, vers l'intérieur de la chambre 26. Sur les côtés de la gorge 56, la paroi inférieure 48 est surélevée de manière à réduire l'espace séparant la paroi inférieure 48 de l'ailette 54 le plus proche. La distance entre l'électrode inférieure 36 et l'ailette la plus proche est du même ordre de grandeur que l'intervalle entre deux ailettes.The lower wall 48 of the chamber has a groove 56 in which is embedded the lower electrode 36, as shown in detail in FIG. figure 3 . The flanges 58 of the groove protrude, relative to the electrode 36, towards the inside of the chamber 26. At the sides of the groove 56, the bottom wall 48 is raised so as to reduce the space separating the wall lower 48 of the fin 54 nearest. The distance between the lower electrode 36 and the nearest fin is of the same order of magnitude as the gap between two fins.

Si l'on prend pour référence géométrique la direction 60 de la tangente à la trajectoire circulaire du contact mobile au moment de la séparation des contacts, on constate que les ailettes 54 sont disposées dans des plans géométriques obliques par rapport à cette direction de référence 60, faisant avec cette direction de référence 60 un angle d'approximativement 30 à 50°. L'électrode 36 formée par l'organe de contact fixe 32 comporte une partie d'extrémité disposée sensiblement parallèlement aux ailettes, perpendiculairement au plan de coupe III-III à l'intérieur de la chambre, et une partie intermédiaire disposée sensiblement perpendiculairement à la direction de référence 60. La paroi postérieure 42 est quant à elle inclinée par rapport à la direction de référence 60, mais également par rapport à un plan de coupe III-III. L'inclinaison de la paroi postérieure 42 est intermédiaire entre la direction 60 et le plan III-III.Taking geometric reference the direction 60 of the tangent to the circular path of the moving contact at the time of the separation of the contacts, we see that the fins 54 are disposed in oblique geometric planes with respect to this reference direction 60 making with this reference direction 60 an angle of approximately 30 to 50 °. The electrode 36 formed by the fixed contact member 32 has an end portion disposed substantially parallel to the fins, perpendicular to the III-III sectional plane inside the chamber, and an intermediate portion disposed substantially perpendicular to the reference direction 60. The posterior wall 42 is in turn inclined with respect to the reference direction 60, but also with respect to a III-III section plane. The inclination of the posterior wall 42 is intermediate between the direction 60 and the plane III-III.

De préférence, la chambre comporte également dans sa partie supérieure une électrode supérieure 62 encastrée couvran une grande partie de la paroi supérieure 50. A la différence de l'électrode inférieure, l'électrode supérieure n'est pas reliée électriquement à l'un des contacts.Preferably, the chamber also comprises in its upper part an upper electrode 62 embedded covers a large part of the upper wall 50. Unlike the lower electrode, the upper electrode is not electrically connected to one of the contact.

Comme illustré sur la figure 2, les ailettes 54 ont une arête 68 formant une découpe délimitant deux ailes de part et d'autre d'un couloir 70. Le couloir s'étend en hauteur depuis la paroi inférieure 48 et l'électrode inférieure 36, jusqu'à la paroi supérieure 50 et l'électrode supérieure 62. Le couloir 70 comporte une partie antérieure évasée 70a faisant face aux contacts. Il comporte une portion longitudinale étroite 70b suivie d'un élargissement du côté opposé aux contacts, à proximité de la cloison postérieure de la chambre, formant une cheminée 70c entre la paroi inférieure 48 et l'électrode inférieure 36 d'une part, et la paroi supérieure 50 et l'électrode supérieure 62 d'autre part. L'électrode inférieure 36 et l'électrode supérieure 62 - ou la paroi supérieure 50, si l'électrode supérieure est absente - sont ainsi directement en regard l'une de l'autre de part et d'autre du couloir. La cheminée 70c est oblongue, c'est-à-dire que sa largeur, mesurée dans une direction perpendiculaire au plan géométrique longitudinale médian est plus grande que sa profondeur, mesurée dans un plan de coupe parallèle à l'une quelconque des ailettes 54. La cheminée 70c est inclinée sensiblement parallèlement à la paroi postérieure, suivant une direction 63.As illustrated on the figure 2 , the fins 54 have an edge 68 forming a cutout defining two wings on either side of a passage 70. The passage extends in height from the lower wall 48 and the lower electrode 36, to the wall upper 50 and the upper electrode 62. The corridor 70 has a flared front portion 70a facing the contacts. It comprises a narrow longitudinal portion 70b followed by an enlargement on the opposite side of the contacts, near the rear wall of the chamber, forming a chimney 70c between the lower wall 48 and the lower electrode 36 on the one hand, and the upper wall 50 and the upper electrode 62 on the other hand. The lower electrode 36 and the upper electrode 62 - or the upper wall 50, if the upper electrode is absent - are thus directly opposite one another on either side of the corridor. The chimney 70c is oblong, that is to say that its width, measured in a direction perpendicular to the median longitudinal geometric plane is greater than its depth, measured in a cutting plane parallel to any of the fins 54. The chimney 70c is inclined substantially parallel to the rear wall, in a direction 63.

L'appareillage fonctionne de la manière suivante. Lors de l'apparition d'un court circuit, le champ électromagnétique induit par le courant circulant dans les conducteurs et notamment dans l'organe de contact fixe 32 en U, engendre dans l'organe de contact mobile 14 des forces électrodynamiques qui repoussent violemment le contact mobile en position de séparation, ce mouvement étant par la suite confirmé par l'ouverture du mécanisme d'entraînement de l'arbre 16. Dès la séparation des contacts 18, 20, un arc électrique naît entre les contacts 18, 20. Cet arc est projeté dans la chambre par les forces électrodynamiques induites par le champ électromagnétique. Lors de son déplacement vers la paroi postérieure 42 et la cheminée 70c, l'arc reste à mi-distance entre les parois latérales 44, 46, car il tend à emprunter le couloir 70b ouvert entre les ailettes. Une convection gazeuse s'établit de la paroi postérieure 42 vers la préchambre 38 en longeant les parois latérales 44, 46 de la chambre, de sorte que la progression de l'arc vers la paroi postérieure 42 n'est pas entravée par une augmentation de pression. Le pied de l'arc migre rapidement le long de l'électrode inférieure 36 jusqu'à la cheminée 70c, avant même que le contact mobile 18 ait atteint sa position finale de séparation. Lors de son déplacement, le pied de l'arc attaque les rebords 58 de la gorge 56 qui génèrent du gaz, provoquant une constriction du pied de l'arc. L'espace libre entre la paroi inférieure 48 et les ailettes 54 est faible, de sorte que la partie basse de la colonne de plasma constituant l'arc est confinée entre l'électrode inférieure et l'ailette la plus proche, ce qui favorise encore la constriction de l'arc. Cette constriction favorise une augmentation rapide de la tension d'arc, et une diminution corrélative de l'intensité du courant. Paradoxalement, l'absence d'espace libre entre la paroi inférieure 48 et la première ailette 54, sur les côtés latéraux de la gorge 56, contribue à stabiliser, voire diminuer la pression régnant dans la chambre, en favorisant la limitation de l'intensité du courant.The apparatus operates in the following manner. When a short circuit occurs, the electromagnetic field induced by the current flowing in the conductors and in particular in the U-shaped fixed contact member 32 generates in the moving contact member 14 electrodynamic forces which repel violently. the movable contact in separation position, this movement being subsequently confirmed by the opening of the drive mechanism of the shaft 16. Upon separation of the contacts 18, 20, an electric arc arises between the contacts 18, 20. This arc is projected into the chamber by the electrodynamic forces induced by the electromagnetic field. During its movement towards the rear wall 42 and the chimney 70c, the arc remains halfway between the side walls 44, 46, since it tends to take the passage 70b open between the fins. Gaseous convection is established from the posterior wall 42 to the prechamber 38 along the side walls 44, 46 of the chamber, so that the progression of the arc towards the posterior wall 42 is not impeded by an increase in pressure. The foot of the arc migrates rapidly along the lower electrode 36 to the stack 70c, even before the movable contact 18 has reached its final separation position. When moving, the foot of the arc attacks the edges 58 of the groove 56 which generate gas, causing a constriction of the foot of the arc. The free space between the bottom wall 48 and the fins 54 is small, so that the lower part of the plasma column constituting the arc is confined between the lower electrode and the nearest fin, which further favors the constriction of the bow. This constriction promotes a rapid increase in arc voltage, and a corresponding decrease in the intensity of the current. Paradoxically, the absence of free space between the bottom wall 48 and the first fin 54, on the lateral sides of the groove 56, contributes to stabilizing or reducing the pressure prevailing in the chamber, by promoting the limitation of the intensity of the current.

La tête de l'arc reste dans un premier temps à l'extrémité saillante de l'organe de contact mobile 14. Du fait de l'inclinaison des ailettes 54, l'arc embrasse dès le début de l'ouverture un grand nombre d'ailettes, ce qui est favorable à un échange thermique important.The head of the arc remains at first at the projecting end of the movable contact member 14. Due to the inclination of the fins 54, the arc embraces from the beginning of the opening a large number of fins, which is favorable to a significant heat exchange.

Lorsque le pont de contact mobile 14 atteint sa position extrême de séparation, le pied de l'arc se trouve à l'extrémité de l'électrode inférieure 36, en bas de la cheminée 70c. L'arc s'incurve davantage de manière à remonter la cheminée 70c de l'extrémité de l'électrode inférieure 36 à l'extrémité de l'électrode supérieure 62, puis à longer l'électrode supérieure 62 qui constitue une surface équipotentielle pour arriver à l'extrémité saillante de l'organe de contact mobile 14 en position de séparation. Dans certains cas, l'arc se divise même en deux arcs en série : un arc long entre l'électrode inférieure 36 et l'électrode supérieure 62 et un arc court entre l'électrode supérieure 62 et l'organe de contact mobile 14. Dans ce cas, la tête de l'arc long migre quasiment instantanément vers le fond de la chambre. Dans tous les cas, l'arc s'installe de manière stable dans la cheminée 70c jusqu'à son extinction. Cette position de l'arc favorise une circulation latérale du gaz dans la chambre, de la cheminée vers le volume d'ouverture, c'est-à-dire un écoulement entre les ailettes 54, le long des parois latérales 44, 46. En circulant ainsi, le gaz se refroidit rapidement par échange avec les ailettes et les parois latérales de la chambre et se contracte. Si l'on excepte les éventuelles fuites par les jointures entre les pièces du boîtier, 1e gaz ne trouve pas d'échappement hors du volume de coupure 52.When the movable contact bridge 14 reaches its extreme position of separation, the foot of the arc is at the end of the lower electrode 36, at the bottom of the chimney 70c. The arc is curved further up the chimney 70c of the end of the lower electrode 36 at the end of the upper electrode 62, then along the upper electrode 62 which constitutes an equipotential surface to reach the projecting end of the movable contact member 14 in the separation position. In some cases, the arc divides even into two arcs in series: a long arc between the lower electrode 36 and the upper electrode 62 and a short arc between the upper electrode 62 and the movable contact member 14. In this case, the head of the longbow migrates almost instantly to the bottom of the chamber. In all cases, the arc is installed stably in the chimney 70c until it goes out. This position of the arc promotes a lateral circulation of the gas in the chamber, from the chimney to the opening volume, that is to say a flow between the fins 54, along the side walls 44, 46. thus circulating, the gas cools rapidly by exchange with the fins and the side walls of the chamber and contracts. Except for any leaks through the joints between the housing parts, the gas finds no exhaust out of the breaking volume 52.

Les ailettes 54 offrent à l'arc une surface d'échange thermique durant toute la coupure, notamment dans leur partie à proximité des arêtes 68. L'arc, tant au moment de sa progression dans la chambre que lorsqu'il est installé dans la cheminée 70c, tend à se dilater pour envahir tout l'espace disponible. Les ailettes 54 contiennent cette dilatation en interagissant avec la périphérie de l'arc.The fins 54 provide the arc with a heat exchange surface during the entire cut, especially in their part near the edges 68. The bow, both as it progresses in the room and when it is installed in the room. chimney 70c, tends to expand to invade all available space. The fins 54 contain this expansion by interacting with the periphery of the arc.

La tension d'arc augmente au fur et à mesure que l'arc se refroidit et que la pression augmente dans le volume de coupure, ce qui permet finalement l'extinction de l'arc lors du passage du courant par zéro.The arc voltage increases as the arc cools and the pressure increases in the breaking volume, which eventually allows the arc to go out when the current passes through zero.

La partie médiane étroite 70b du couloir 70 favorise la migration de l'arc vers le fond de la chambre, et la cheminée 70c stabilise l'arc dans cette région. En effet, les essais comparatifs montrent que si l'on pratique une cheminée au fond de la chambre sans couloir intermédiaire, l'arc ne parvient pas toujours jusqu'à la cheminée, et qu'inversement, si l'on a un couloir sans cheminée, l'arc ne s'installe pas au fond du couloir de sorte que l'on assiste à des reclaquages répétitifs d'arc entre les contacts. C'est donc la conjonction de la partie intermédiaire étroite 70b du couloir et de la cheminée 70c qui permet d'éloigner rapidement et durablement l'arc des contacts.The narrow middle portion 70b of the passage 70 promotes the migration of the arc to the bottom of the chamber, and the chimney 70c stabilizes the arc in this region. Indeed, the comparative tests show that if you practice a chimney at the bottom of the room without intermediate corridor, the arc does not always reach the chimney, and that inversely, if one has a corridor without chimney, the bow does not install at the bottom of the hallway so that there is repetitive arc reclining between the contacts. It is therefore the conjunction of the narrow intermediate portion 70b of the corridor and the chimney 70c which allows to quickly and sustainably move the arc contacts.

La figure 5 illustre un deuxième mode de réalisation de l'invention, dans lequel chacune des ailettes planes du premier mode de réalisation est remplacée par deux ailettes latérales 154a, 154b. Chaque ailette latérale est alors munie d'une languette d'encastrement dans la paroi postérieure et d'une languette d'encastrement dans la paroi latérale. Cette variante simplifie la fabrication des ailettes, et permet éventuellement un montage des ailettes en quinconce.The figure 5 illustrates a second embodiment of the invention, wherein each of the planar fins of the first embodiment is replaced by two lateral wings 154a, 154b. Each lateral wing is then provided with a recess tongue in the rear wall and a tongue recess in the side wall. This variant simplifies the manufacture of the fins, and possibly allows a mounting fins staggered.

On rencontre une difficulté particulière avec l'architecture symétriques des modes de réalisation précédents, lorsque l'on cherche à diminuer la largeur de la chambre, c'est-à-dire la distance entre les parois latérales de la chambre. Lorsque l'on dispose le couloir à mi-chemin des parois latérales dans une chambre étroite, on n'obtient pas la circulation des gaz recherchée. En effet, la dimension des ailettes est alors faible de sorte que les parois latérales ont un rôle prédominant dans l'écoulement des gaz. Cet effet indésirable se fait sentir notamment une fois que l'arc est installé dans la cheminée et qu'il projette des gaz vers le volume d'ouverture. On constate alors que les gaz ont du mal à s'engouffrer entre les ailettes et ont tendance à emprunter directement le couloir, et que par conséquent, il ne rencontrent pas de surface d'échange permettant de les refroidir.There is a particular difficulty with the symmetrical architecture of the previous embodiments, when seeking to reduce the width of the chamber, that is to say the distance between the side walls of the chamber. When the corridor is located midway between the side walls in a narrow chamber, the desired gas flow is not obtained. Indeed, the dimension of the fins is then small so that the side walls have a predominant role in the flow of gases. This undesirable effect is particularly felt once the arc is installed in the chimney and throws gases to the opening volume. It is then found that the gases have difficulty in rushing between the fins and tend to borrow directly from the corridor, and therefore, they do not encounter exchange surface to cool them.

Un troisième mode de réalisation de l'invention, illustré sur la figure 6, a donc été développé spécifiquement pour un appareil de faible largeur muni d'une chambre d'extinction d'arc étroite. Le couloir 270 longe directement l'une des parois latérales 246 et est délimité du côté latéral opposé par des ailettes 254, plaquées contre la paroi latérale 244. La largeur des ailettes, mesurée entre le couloir 270 et la paroi 244, est alors suffisante pour que les parois latérales n'entravent pas significativement la pénétration des gaz entre les ailettes 254. Les essais montrent que les gaz pénètrent bien entre les ailettes 254 et s'y refroidissent. Toutefois, l'exposition directe de la paroi 246 à l'arc rend ce dispositif délicat à maîtriser et impose une paroi non gazogène et de bonne capacité calorifique, par exemple en céramique poreuse.A third embodiment of the invention, illustrated on the figure 6 , was therefore developed specifically for a narrow-width apparatus with a narrow arc extinction chamber. The corridor 270 runs directly along one of the side walls 246 and is delimited on the opposite lateral side by fins 254, pressed against the side wall 244. The width of the fins, measured between the passage 270 and the wall 244, is then sufficient to that the side walls do not significantly impede the penetration of gas between the fins 254. The tests show that the gases penetrate well between the fins 254 and cool there. However, the direct exposure of the wall 246 to the arc makes this device difficult to control and requires a non-gasogenic wall and good heat capacity, for example porous ceramic.

Un quatrième mode de réalisation de l'invention, également développé pour les chambres étroites, est illustré sur la figure 7 et résout ce problème résiduel. Sur la figure, on a utilisé dans la mesure du possible, pour des parties correspondant à des parties similaires du premier mode de réalisation, les signes de référence utilisés dans le premier mode de réalisation, augmentés de 300. Pour décrire en détail ce mode de réalisation, on prendra pour référence géométrique un plan médian 302 de la chambre, situé à mi-distance des parois latérales 344, 346 de la chambre. Les contacts 318 sont situés déporté latéralement par rapport au plan médian 302. Les séparateurs 354 sont découpés de manière à définir un couloir 370 comportant une embouchure 370a, une partie médiane 370b et une cheminée 370c. La partie médiane 370b s'étend de façon oblique par rapport au plan de médian. Ainsi, le couloir 370 se rapproche de l'une des paroi latérales en s'éloignant du volume d'ouverture 338. Entre la partie médiane du couloir 370b et la paroi 344, les ailettes ont une faible largeur, alors que de l'autre côté du couloir 370b, la largeur des ailettes est plus importante. Ce phénomène s'accentue en se rapprochant du fond de la chambre. La cheminée 370c est constituée dans ce mode de réalisation par un coude du couloir. L'insertion de l'arc dans le couloir 370 n'est pas entravée par la disposition particulière du couloir, car celui-ci reste dans un plan radial par rapport à l'axe géométrique de référence. Les parois latérales 344, 346 de la chambre sont suffisamment protégées de l'arc du fait de l'interposition des ailettes 354, même du côté où celles-ci sont plus étroites. Une fois que le coude 370c est atteint, l'arc s'installe dans la cheminée 370c et y reste. Les gaz émis à la périphérie de l'arc trouvent alors entre le couloir 370b et la paroi 346 des ailettes larges qui assurent un refroidissement efficace et qui permettent également un écoulement suffisant. Cette disposition offre l'avantage par rapport au mode de réalisation de la figure 6, de protéger la paroi latérale 344 de la chambre située du côté des ailettes étroites, sans pour autant entraver l'écoulement des gaz.A fourth embodiment of the invention, also developed for narrow chambers, is illustrated on the figure 7 and solves this residual problem. In the figure, reference signs used in the first embodiment have been used as far as possible for parts corresponding to similar parts of the first embodiment. embodiment, increased by 300. To describe in detail this embodiment, we will take for geometric reference a median plane 302 of the chamber, located midway from the side walls 344, 346 of the chamber. The contacts 318 are located laterally offset from the median plane 302. The separators 354 are cut to define a corridor 370 having a mouth 370a, a middle portion 370b and a chimney 370c. The middle part 370b extends obliquely with respect to the median plane. Thus, the corridor 370 approaches one of the side walls away from the opening volume 338. Between the middle portion of the corridor 370b and the wall 344, the fins have a small width, while the other side of the corridor 370b, the width of the fins is greater. This phenomenon is accentuated by approaching the bottom of the room. The chimney 370c is constituted in this embodiment by an elbow of the corridor. The insertion of the arc in the corridor 370 is not impeded by the particular arrangement of the corridor, because it remains in a radial plane with respect to the reference geometric axis. The side walls 344, 346 of the chamber are sufficiently protected from the arc due to the interposition of the fins 354, even on the side where they are narrower. Once the elbow 370c is reached, the arc is installed in the chimney 370c and remains there. The gases emitted at the periphery of the arc then find between the passage 370b and the wall 346 wide fins which provide efficient cooling and which also allow sufficient flow. This arrangement offers the advantage over the embodiment of the figure 6 , to protect the side wall 344 of the chamber located on the narrow fins side, without impeding the flow of gas.

Naturellement, diverses autres modifications sont possibles.Naturally, various other modifications are possible.

L'électrode supérieure peut être omise dans certains cas.The upper electrode may be omitted in some cases.

Les ailettes sont de préférence parallèles les unes aux autres, ce qui favorise un écoulement homogène du gaz et un échange continue avec toute la surface des ailettes. Toutefois, d'autres dispositions peuvent être envisagées.The fins are preferably parallel to each other, which promotes a uniform flow of gas and a continuous exchange with the entire surface of the fins. However, other provisions may be considered.

L'angle d'inclinaison des ailettes par rapport à la direction de référence peut être plus ou moins important, entre 0 et 90°, de manière typique entre 30 et 60°. On constate qu'une forte inclinaison favorise la monté en tension de l'arc au début de l'ouverture, sans doute du fait qu'au début de l'ouverture, le pied de l'arc est rapidement projeté vers l'extrémité libre de l'électrode par l'effet électromagnétique de l'organe de contact en U, de sorte que l'arc est lui-même incliné et peut embrasser un plus grand nombre d'ailettes si ceux-ci sont eux-mêmes inclinés.The angle of inclination of the fins relative to the reference direction may be greater or less, between 0 and 90 °, typically between 30 and 60 °. It can be seen that a strong inclination favors the rise in tension of the arc at the beginning of the opening, probably because at the beginning of the opening, the foot of the arc is rapidly projected towards the free end of the electrode by the electromagnetic effect of the contact member U, so that the arc is itself inclined and can embrace a greater number of fins if they are themselves same inclined.

La circulation des gaz latéralement de la cheminée vers la préchambre peut être favorisée par la mise en place de cloisons isolantes intermédiaires parallèles aux parois latérales et délimitant avec celles-ci des canaux latéraux de part et d'autre du couloir médian.The flow of gas laterally from the chimney to the prechamber can be promoted by the establishment of intermediate insulating partitions parallel to the side walls and delimiting with them lateral channels on either side of the median corridor.

L'invention s'applique aussi bien au pôle à double coupure, ayant un pont de contact mobile et deux chambres de coupure par pôle, qu'à un pôle ne comportant qu'une chambre d'extinction d'arc par pôle. Le contact mobile peut être rotatif ou mobile en translation.The invention applies both to the double-break pole, having a movable contact bridge and two breaking chambers per pole, to a pole having only one arc extinction chamber per pole. The movable contact may be rotatable or movable in translation.

Le contact fixe 20 peut être remplacé par un contact mobile, entraîné par le mécanisme d'entraînement des contacts en opposition avec le contact 22, ou par un contact semi-mobile, entraîné par un ressort de pression de contact.The fixed contact 20 may be replaced by a movable contact, driven by the driving mechanism of the contacts in opposition with the contact 22, or by a semi-moving contact, driven by a contact pressure spring.

L'invention, bien qu'elle trouve son application première aux chambres d'extinction étanches, est également applicable à des chambres d'extinction d'arc munie d'un orifice d'évacuation des gaz. Dans ce cas, il paraît préférable d'éviter tout échappement à proximité du bas de la cheminée et de l'électrode inférieure. Un échappement par le haut de la cheminée, à proximité de l'électrode supérieure ou par des orifices pratiqués dans l'électrode supérieure est possible.The invention, although it finds its prime application in sealed extinguishing chambers, is also applicable to arc extinguishing chambers provided with a gas evacuation port. In this case, it seems preferable to avoid any escape near the bottom of the chimney and the lower electrode. An exhaust from the top of the chimney, near the upper electrode or through holes in the upper electrode is possible.

Claims (12)

  1. Electrical switchgear apparatus, comprising:
    - a case (12) defining a longitudinal geometric reference plane (I-I) and delineating:
    - an opening volume (38) and
    - an arc extinguishing chamber (26) opening out onto the opening volume (38) and bounded by two opposite side panels (44, 46) parallel to the geometric reference plane, a rear panel (42) located away from the opening volume (38), a bottom panel (48) and a top panel (50);
    - a pair of separable contacts arranged in the opening volume (38) and comprising a first contact (18), movable along a flat path in the geometric reference plane between a contact position and a separated position, and a second contact (20);
    - cooling fins (54) arranged inside the arc extinguishing chamber (26), perpendicularly to the geometric reference plane, each fin having a free attack edge (68) exposed to the arc;
    - a bottom longitudinal electrode (36) in electrical connection with the second contact (20), the bottom electrode (36) at least partially covering the bottom panel (48) of the chamber (26);
    characterized in that:
    the free edges (68) laterally bound a gulley extending in the heightwise direction from the bottom electrode (36) to the top panel (50), the gulley having:
    - a first tapered longitudinal end (70a) opening out onto the opening volume (38),
    - a second broadened longitudinal end forming a stack (70c) near the rear panel, the stack (70c) having an oblong cross-section in a plane of cross-section parallel to the fins (54),
    - a narrow intermediate portion (70b) joining the first longitudinal end (70a) to the stack, the bottom electrode extending longitudinally in the gulley from the second contact to the stack at least.
  2. Apparatus according to claim 1, characterized in that the fins have a given thickness and are separated two by two by a given distance which is of the same order of magnitude as said thickness.
  3. Apparatus according to either one of claims 1 or 2, characterized in that the stack is limited to the rear by the rear panel.
  4. Apparatus according to any one of the foregoing claims, characterized in that the rear panel is devoid of any gas outlet orifices.
  5. Apparatus according to any one of the foregoing claims, characterized in that the chamber (26) and opening volume (38) together form a closed breaking volume (52).
  6. Apparatus according to any one of the foregoing claims, characterized in that the bottom longitudinal electrode (36) is separated from the fins by a distance which is the same order of magnitude as the thickness of the fins.
  7. Apparatus according to any one of the foregoing claims, characterized in that each fin (54) is provided with at least one lateral fixing tab (55a) secured in a slit of one of the side panels (44, 46), and with at least one rear fixing tab (55b) secured in a slit of the rear panel (42).
  8. Apparatus according to any one of the foregoing claims, characterized in that the fins (54) are parallel to one another.
  9. Apparatus according to claim 8, characterized in that the rear panel (42) is inclined with respect to the fins.
  10. Apparatus according to any one of the foregoing claims, characterized in that the gulley (70) extends appreciably in the geometric reference plane, at equal distance from the side panels (44, 46) of the chamber (26).
  11. Apparatus according to any one of claims 1 to 8, characterized in that the narrow intermediate part of the gulley (70) is located closer to one of the side panels when moving away from the opening volume.
  12. Apparatus according to any one of the foregoing claims, characterized in that the apparatus (10) is a limiting circuit breaker comprising rigid input conductors (10, 14) for conveying current to the contacts (18, 20), these rigid conductors being shaped in such a way that, when a current flows therethrough, they generate an intense electromagnetic field near the contacts (18, 20) such as to cause electromagnetic repulsion of the movable contact (20) to the separated position and to project the electric arc into the chamber (26).
EP03354028A 2002-04-29 2003-03-25 Electrical switching device having an arc extinguishing chamber with deionization plates Expired - Lifetime EP1359596B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0205344 2002-04-29
FR0205344A FR2839195B1 (en) 2002-04-29 2002-04-29 ELECTRICAL SWITCHING APPARATUS COMPRISING AN ARC EXTINGUISHING CHAMBER PROVIDED WITH DEIONIZING FINS

Publications (2)

Publication Number Publication Date
EP1359596A1 EP1359596A1 (en) 2003-11-05
EP1359596B1 true EP1359596B1 (en) 2010-11-17

Family

ID=28800004

Family Applications (1)

Application Number Title Priority Date Filing Date
EP03354028A Expired - Lifetime EP1359596B1 (en) 2002-04-29 2003-03-25 Electrical switching device having an arc extinguishing chamber with deionization plates

Country Status (5)

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US (1) US6794595B2 (en)
EP (1) EP1359596B1 (en)
CN (1) CN1270336C (en)
DE (1) DE60334953D1 (en)
FR (1) FR2839195B1 (en)

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Also Published As

Publication number Publication date
US6794595B2 (en) 2004-09-21
CN1455425A (en) 2003-11-12
EP1359596A1 (en) 2003-11-05
US20030201853A1 (en) 2003-10-30
FR2839195B1 (en) 2004-07-23
FR2839195A1 (en) 2003-10-31
DE60334953D1 (en) 2010-12-30
CN1270336C (en) 2006-08-16

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