EP2124236A1 - Use of an electric contact material to blow an electric arc - Google Patents
Use of an electric contact material to blow an electric arc Download PDFInfo
- Publication number
- EP2124236A1 EP2124236A1 EP08156731A EP08156731A EP2124236A1 EP 2124236 A1 EP2124236 A1 EP 2124236A1 EP 08156731 A EP08156731 A EP 08156731A EP 08156731 A EP08156731 A EP 08156731A EP 2124236 A1 EP2124236 A1 EP 2124236A1
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- European Patent Office
- Prior art keywords
- magnetic
- entities
- pads
- magnetized
- use according
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Classifications
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- 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
- H01H9/44—Means for extinguishing or preventing arc between current-carrying parts using blow-out magnet
- H01H9/446—Means for extinguishing or preventing arc between current-carrying parts using blow-out magnet using magnetisable elements associated with the contacts
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/0094—Switches making use of nanoelectromechanical systems [NEMS]
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/02—Contacts characterised by the material thereof
- H01H1/021—Composite material
- H01H1/023—Composite material having a noble metal as the basic material
- H01H1/0237—Composite material having a noble metal as the basic material and containing oxides
- H01H1/02372—Composite material having a noble metal as the basic material and containing oxides containing as major components one or more oxides of the following elements only: Cd, Sn, Zn, In, Bi, Sb or Te
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/49117—Conductor or circuit manufacturing
- Y10T29/49124—On flat or curved insulated base, e.g., printed circuit, etc.
Definitions
- the present invention relates to the field of electrical contacts. It relates, more particularly, to the use of an electrical contact material with arc extinguishing effect.
- Such a type of material finds its application mainly for the realization of so-called "low voltage" contacts, that is to say whose operating range is approximately between 10 and 1000V and between 1 and 10000A.
- These contacts are generally used in the domestic, industrial and automotive fields, both in direct current and AC, for switches, relays, contactors and circuit breakers, etc.
- the energy released by the electric arc is sufficient to melt the material constituting the pads, which entails not only the degradation of the metal parts but also, sometimes, their welding, with the consequence of blocking the device.
- one solution consists in using pseudoalloys comprising a silver or copper matrix and, inserted in this matrix, a fraction consisting of approximately 10 to 50% by volume of refractory particles (for example , Ni, C, W, WC, CdO, SnO 2 ) of a size generally between 1 and 5 microns.
- refractory particles for example , Ni, C, W, WC, CdO, SnO 2
- This method does not allow to limit the mergers and, because of their repetition, problems of erosion and welding of the studs can occur in the short or medium term.
- Another solution, described in the US patent US 3,626,124 consists in using a material comprising single-domain magnetic particles. Such particles are spontaneously magnetized in an orientation random in the absence of an applied external field. The field generated by each magnetized particle acts on the arc of cutoff, facilitating its blowing. The particles described remain monodomain even after a heating beyond their Curie temperature so that the blowing efficiency is not affected by the heating due to the arc of cutoff, during openings previous contacts. However, each particle acts individually on the breaking arc so that the magnetic blow effect is very small. This solution is therefore not satisfactory.
- An object of the present invention is therefore to overcome these disadvantages, by proposing to use an electrical contact material to make contact pads whose operation is not impaired in the short term or in the long term by the energy an electric arc.
- the invention relates to the use of a material comprising a matrix of conductive metal and magnetic entities representing between 8 and 80% by weight of the material and comprising hard magnetic phases, said magnetic entities being non-magnetized and being capable of being made magnetized with a mean orientation, defined by the direction of a magnetic field applied to said material, for blowing an electric arc between two pads of electrical contacts, at least one of which comprises said material, and thereby reducing the duration of the arc.
- the invention also relates to the use of a material comprising a matrix of conductive metal and magnetic entities representing between 8 and 80% by weight of the material and comprising hard magnetic phases, said magnetic entities initially not magnetized having been made magnetized with an average orientation, defined by the direction of a magnetic field applied to said material, for blowing an electric arc between two pads of electrical contacts, at least one of which comprises said material, and thus reducing the duration of the arc.
- the material may further comprise a stable refractory fraction at a temperature greater than 900 ° C.
- At least one of the phases of the magnetic entities is a hard magnetic compound based on rare earths.
- said material is capable of generating a magnetic induction field, measured at its surface, greater than 20 mT, preferably greater than 60 mT, and more preferably greater than 100 mT.
- At least one of said pads which comprises said material with the magnetic entities has an overlayer comprising a material selected from silver and copper.
- the present invention relates to a material comprising a conductive metal matrix and magnetic entities representing between 8 and 80% by weight of the material and comprising phases magnetic resins, said magnetic entities being non-magnetized and capable of being magnetized with a mean orientation, defined by the direction of a magnetic field applied to said material, at least one of the magnetic phases being a land-based compound rare, with the exception of the samarium.
- the present invention also relates to a material comprising a matrix of conductive metal and magnetic entities representing between 8 and 80% by weight of the material and comprising hard magnetic phases, said magnetic entities initially not magnetized having been made magnetized with a mean orientation, defined by the direction of a magnetic field applied to said material, at least one of the magnetic phases being a compound based on rare earths, with the exception of the samarium.
- the invention relates to a pair of pads of electrical contacts, said pads defining between them an axis, characterized in that at least one of said pads is made of a material as defined above and presents a magnetization generating a magnetic field perpendicular to said axis.
- a pair of electrical contact pads comprising, at the cathode, a contact pad made of a material defined above.
- the material used according to the invention initially contains multidomain magnetic entities forming a set initially initially unmagnetized, and then to be magnetized by the application of a field.
- the material used according to the invention does not initially contain spontaneously magnetized monodomain entities.
- the magnetic entities represent between 10 and 50% by weight of the material, preferably between 12 and 30% by weight, and more preferably between 18 and 22% by weight of said material.
- Magnetic entities include magnetic phases that can be obtained from one or more ferromagnetic or ferrimagnetic hard compounds.
- they are chosen from compounds based on rare earths, among which mention may be made of the so-called RE-Fe-B type compounds (RE being the abbreviation of Rare Earth, Rare Earth).
- RE is neodymium or praseodymium.
- Other compounds of the RE-M type can be used, RE being preferably La, Gd, Y or Lu, of the 1/5, 1/7 or 2/17 type, and M being predominantly Co or Fe and possibly containing Cu, Zr, Al and other minority elements.
- the compounds of the RE-Fe-N type can also be used.
- the magnetic entities have a coercive field and a residual induction sufficient to allow their use in the targeted applications, these two parameters can be evaluated by simple experimental tests. Indeed, as will be explained below, it is necessary that the contact generates a certain magnetic field so as to destabilize a possible electric arc occurring between the pads. In particular, it must be that after having been exposed to a magnetic field, the material has a sufficient and stable long-term residual induction for long-term use.
- This induction obtained by magnetization of the pads under an external magnetic field, can be characterized by the magnetic field generated on the surface of the pads, and persistent after removal of the applied magnetic field. As an indication, the field generated on the surface must be greater than 20 mT, preferably 60 mT, and more preferably greater than 100 mT, measured using a Hall effect probe distributed by Lakeshore.
- the matrix comprises a refractory fraction, stable at a temperature above 900 ° C.
- the refractory fraction may comprise one or more of the elements selected from the following group: CdO, SnO 2 , ZnO, Bi 2 O 3 , C, WC, MgO, In 2 O 3 , as well as Ni, Fe, Mo, Zr , W or their oxides.
- the refractory fraction is added in an amount so that the percentage of magnetic entities is at least 8% and the amount of conductive metal is at least 20%.
- the magnetic entities are dispersed in the matrix, either regularly, or according to a concentration gradient, or again in localized blocks.
- the material may also contain dopants or minor additives, facilitating the use of the material, which may be, for example, Ni, Co, Fe, Bi, Re, Zr and their oxides.
- the material described above is used to make pads of electrical contacts.
- the first steps of the process of developing the material and forming the contact pads are common and are known to those skilled in the art who can choose between several techniques.
- the method comprises an additional step of magnetizing the material on the already developed pads.
- the material preparation step may be carried out by powder metallurgy, one of the magnetic entities being nanostructured RE-Fe-B, where RE is a rare earth element.
- a preferred direction of the magnetic entities may be obtained by applying a suitable method during the development of the pads (pressure, magnetic field, heat treatment). This operation is not essential but it makes it possible to increase the magnetization of the studs induced by the field, applied after elaboration of the pads.
- the use, as a starting material for constituting the magnetic entities of the contact, of a nanostructured tape of RE-Fe-B obtained by a rapid solidification technique, particularly by the technique known as melt spinning gives excellent results. It is not necessary to further describe this technique known to those skilled in the art. In summary, it consists in flowing, through a nozzle, molten metal contained in a reservoir, and in bringing a net of liquid metal in contact with a cylinder, for example copper, rotating great speed. Thanks to this technique, the RE-Fe-B cools by taking a microstructure, which allows it to present remarkable hard magnetic characteristics for the intended use.
- the RE-Fe-B can be combined with other magnetic materials to optimize the magnetic properties of the assembly, the RE-Fe-B advantageously representing at least 50% by weight of the magnetic entities.
- Contact pads are then shaped by cutting strips, stamping son, unit compression. They are then arranged on a suitable support, by any traditional method of assembling electrical contacts, in particular: resistance welding, resistance brazing, induction brazing, flame or oven brazing, crimping, incrustation ... view of their use as electrical contacts.
- the material used according to the invention can be formed into a washer or a layer, forming a magnetic system, made integral with a traditional electrical contact pad by incrustation, welding, brazing or riveting, or by layer deposition (s).
- the magnetic material, the contact material or both may be in the form of one or more layers.
- the magnetic system can also serve as a mechanical support and supply current to the electrical contact. It is advantageously possible to adapt the magnetic system according to the variant in existing installations, while retaining the initial contact material, since it occupies only a small space in addition to the contact, unlike the electromagnetic members of the prior art.
- the magnetic entities are not magnetized.
- the pads must then undergo the magnetization step by applying a magnetizing magnetic field to provide the magnetic non-magnetized entities global magnetization in a mean orientation defined by the applied field.
- the studs can then fully play their role of blower or arc extinguisher. This operation can take place in the factory, after development of the stud. It can also take place at the user, before or after the final assembly of the contact. It is performed by exposing the pads to a magnetic field of an intensity of between 0.5 and 30 T, preferably between 1 and 30 T, and even more preferably between 1 and 10 T.
- the material used in the form of pads comprises initially unmagnetized magnetic entities that are either susceptible to being magnetized by the application of a magnetic field to the user, or already magnetized by the application of a magnetic field in the factory.
- the field may in particular be applied in parallel or preferably perpendicular to the longitudinal axis of a stud, so that the latter has field lines as illustrated, respectively, on the Figures 1a and 1b .
- the conditions of the magnetization step are adapted to the magnetic material so that, after having undergone the magnetization step, the studs are source of a magnetic induction field, which, measured at their surface, is greater than 20 mT, preferably 60 mT, and more preferably greater than 100 mT.
- the pads thus obtained are then implemented in electrical contacts formed of two pads defining between them a first axis.
- the contact may comprise a single pad obtained according to the above method, arranged in the case of a DC circuit, the anode or the cathode. It is also possible that the two studs forming the contact are made of a magnetic material used according to the invention. Various magnetic field orientations are possible and conceivable, for example, when a single magnetic pad is used, the field it generates can be oriented parallel or perpendicular to the first axis.
- the stud may comprise an overlay deposited on the magnetic material.
- Such an overcoat comprises a conductive material chosen from silver and copper and optionally a refractory compound chosen from the group comprising compounds CdO, SnO 2 , ZnO, Bi 2 O 3 , C, WC, MgO, In 2 O 3 , as well as Ni, Fe, Mo, Zr, W or their oxides.
- the overlay advantageously makes it possible to isolate the magnetic entities from the stud of the contact surface and thus to reduce the risks of soldering on closing. Indeed, the blowing effect can be attenuated by the ionization of the constituent elements of the magnetic compound, the latter can increase the contact resistance and promote welding. In any case, the extreme surface of the contact is strongly heated under the effect of the arc so that the magnetic properties of the surface entities are generally destroyed in operation.
- the overlayer must be thin enough so that the field created by the underlying magnetic entities in the arc area remains sufficiently intense, and possibly thick enough not to be completely melted under the effect of the arc. However, it turns out that the reduction in the duration of the arc obtained according to the invention leads to very low erosion.
- the overlay may have a thickness of between 0.05 mm and 3 mm, preferably between 0.1 mm and 2 mm, and more preferably between 0.2 mm and 1 mm.
- the powder thus obtained is mixed with powdered silver, the particles of which have a mean diameter of between 15 and 50 ⁇ m.
- the mixture is produced in a mass proportion of 80% of silver and 20% EM magnetic entity powder.
- a magnetic material is obtained constituting an electrical contact pad.
- An electrical contact pad is then shaped by unitary compression and compacted under a pressure of 700 MPa.
- the pad is then sintered under vacuum at 400 ° C for about 30 minutes.
- the pad is then assembled on a support according to one of the techniques mentioned above, for use in an electrical contact.
- the pad is magnetized by exposing it to a magnetic field of 8 T.
- the pad is oriented perpendicular to the magnetic field, as illustrated on the figure 1a so that it has a magnetization perpendicular to its longitudinal axis.
- the pad is a source of a remanent induction field of about 60 mT at the surface.
- the pad obtained above is then used in a contact of a resistive-type electrical circuit, operating under a 42 V DC voltage, with an intensity of 37.5 A.
- a magnet pad is disposed at the cathode, the other being silver.
- the opening arc duration is measured. Closing tests are also performed to simulate the risks of welding, under the same conditions as for the opening, but with a current of 90 A. The percentage of welding obtained, whose breaking force is greater than 0, is measured. 1 N.
- Example 1 is reproduced by replacing 6% by weight of silver of the matrix with 6% by weight of a refractory compound (SnO 2 ).
- An overlayer 0.6 mm thick is applied to the magnetic material of the pad obtained in Example 1.
- Said overlayer comprises 100% silver.
- Example 1 is reproduced by not subjecting the pad to a magnetization (Example 4) or by using other materials to make the pads of the contact (Examples 5 and 6).
- Example 4 shows the importance of the magnetization step of the stud since a contact comprising a non-magnetized stud has an arc duration at the opening of 9 ms while the contact comprising the magnetic pin has a arc duration at opening of 3 ms.
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- Arc-Extinguishing Devices That Are Switches (AREA)
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Abstract
Description
La présente invention se rapporte au domaine des contacts électriques. Elle concerne, plus particulièrement, l'utilisation d'un matériau de contact électrique avec effet d'extinction d'arc.The present invention relates to the field of electrical contacts. It relates, more particularly, to the use of an electrical contact material with arc extinguishing effect.
Un tel type de matériau trouve son application principalement pour la réalisation de contacts dits "basse tension", c'est-à-dire dont la plage de fonctionnement se situe approximativement entre 10 et 1000V et entre 1 et 10000A. Ces contacts sont utilisés généralement dans les domaines domestique, industriel et automobile, aussi bien en courant continu qu'en courant alternatif, pour des interrupteurs, des relais, des contacteurs et des disjoncteurs, etc.Such a type of material finds its application mainly for the realization of so-called "low voltage" contacts, that is to say whose operating range is approximately between 10 and 1000V and between 1 and 10000A. These contacts are generally used in the domestic, industrial and automotive fields, both in direct current and AC, for switches, relays, contactors and circuit breakers, etc.
Lorsqu'on ouvre une paire de plots de contacts électriques sous tension, le courant continue de passer d'un plot à l'autre en ionisant le gaz qu'il traverse. Cette colonne de gaz ionisé, communément appelée "arc électrique", a une longueur maximum qui dépend de différents paramètres tels que la nature et la pression du gaz, la tension aux bornes, le matériau de contact, la géométrie de l'appareil, l'impédance du circuit, etc.When a pair of pads of electrical contacts under tension is opened, the current continues to pass from one pad to the other by ionizing the gas through which it passes. This column of ionized gas, commonly called "electric arc", has a maximum length that depends on various parameters such as the nature and pressure of the gas, the terminal voltage, the contact material, the geometry of the device, the impedance of the circuit, etc.
L'énergie dégagée par l'arc électrique est suffisante pour fondre le matériau constituant les plots, ce qui entraîne, non seulement, la dégradation des parties métalliques mais, aussi, parfois, leur soudure, avec pour conséquence le blocage de l'appareil.The energy released by the electric arc is sufficient to melt the material constituting the pads, which entails not only the degradation of the metal parts but also, sometimes, their welding, with the consequence of blocking the device.
Dans les applications en courant alternatif, le passage de la tension par zéro facilite la coupure de l'arc. Néanmoins, certains appareils de protection doivent couper des courants très élevés, qui occasionnent des arcs suffisamment énergétiques pour endommager les contacts.In AC applications, the zero-crossing of the voltage facilitates the breaking of the arc. Nevertheless, some protective devices have to cut very high currents, which cause arcs sufficiently energetic to damage the contacts.
En revanche, pour les applications en courant continu, les arcs électriques sont très stables, surtout lorsque la tension est nettement supérieure à 10V. Une solution pour couper l'arc consiste à augmenter sa longueur de façon telle qu'il devienne instable et disparaisse de lui-même. Pour une tension de 14V, une distance de l'ordre du millimètre est suffisante alors que pour une tension de 42V, particulièrement lorsqu'on est en présence d'une charge inductive, cette distance peut être de plusieurs centimètres. Ceci complique sérieusement la construction des appareils de coupure et la durée des arcs créés réduit fortement leur durée de vie.On the other hand, for DC applications, arcing is very stable, especially when the voltage is well above 10V. A solution to cut the arc is to increase its length so that it becomes unstable and disappears on its own. For a voltage of 14V, a distance of the order of a millimeter is sufficient whereas for a voltage of 42V, particularly when in the presence of an inductive load, this distance can be several centimeters. This seriously complicates the construction of the cut-off devices and the duration of the arcs created greatly reduces their service life.
Le problème se pose tout particulièrement dans l'industrie de l'automobile qui envisage l'utilisation de circuits à 42V continus voire plus pour s'adapter au nombre toujours plus élevé de dispositifs électriques présents dans les voitures (jusqu'à cent moteurs dans un véhicule haut-de-gamme). A de telles tensions, l'intérêt de limiter les problèmes liés aux arcs devient primordial.The problem arises particularly in the automobile industry which is considering the use of continuous 42V circuits or more to adapt to the ever increasing number of electrical devices present in cars (up to one hundred engines in one high-end vehicle). At such tensions, the interest of limiting the problems related to arcs becomes paramount.
Ainsi, les matériaux des contacts électriques doivent satisfaire les trois exigences suivantes:
- une résistance de contact faible et stable pour éviter un échauffement excessif lors du passage du courant ;
- bonne résistance au soudage en présence d'un arc électrique ; et
- faible érosion sous l'effet de l'arc.
- a low and stable contact resistance to prevent overheating during current flow;
- good resistance to welding in the presence of an electric arc; and
- weak erosion under the effect of the arc.
Pour satisfaire ces exigences partiellement contradictoires, une solution consiste à utiliser des pseudo-alliages comportant une matrice d'argent ou de cuivre et, insérée dans cette matrice, une fraction constituée d'environ 10 à 50% en volume de particules réfractaires (par exemple, Ni, C, W, WC, CdO, SnO2) d'une taille généralement comprise entre 1 et 5 µm. Le matériau ainsi obtenu résiste mieux à l'énergie dégagée par l'arc électrique. Bien que constituant une solution intéressante, cette méthode ne permet pas de limiter les fusions et, à cause de leur répétition, des problèmes d'érosion et de soudage des plots peuvent survenir à court ou moyen terme.In order to satisfy these partially contradictory requirements, one solution consists in using pseudoalloys comprising a silver or copper matrix and, inserted in this matrix, a fraction consisting of approximately 10 to 50% by volume of refractory particles (for example , Ni, C, W, WC, CdO, SnO 2 ) of a size generally between 1 and 5 microns. The material thus obtained is more resistant to the energy released by the electric arc. Although an interesting solution, this method does not allow to limit the mergers and, because of their repetition, problems of erosion and welding of the studs can occur in the short or medium term.
Une autre solution, décrite dans le brevet américain
Par ailleurs, lorsqu'il s'agit, en courant alternatif, de réaliser des appareils de protection (disjoncteurs) capables de couper des courants très élevés, on a proposé de recourir à des moyens auxiliaires pour faciliter l'extinction de l'arc ou éviter son rallumage: soufflage électromagnétique ou pneumatique.Furthermore, when it comes, in alternating current, to make protection devices (circuit breakers) capable of cutting very high currents, it has been proposed to use auxiliary means to facilitate the extinction of the arc or avoid re-ignition: electromagnetic or pneumatic blow.
Par exemple, une telle solution d'extinction électromagnétique par des dispositifs extérieurs au contact lui-même est décrite dans le document
On a entre autre proposé de remplacer le gaz présent dans l'espace séparant les deux contacts par un gaz très stable et donc difficile à ioniser, comme du SF6. Cependant, cette solution est complexe à mettre en oeuvre.Among other things, it has been proposed to replace the gas present in the space separating the two contacts with a gas that is very stable and therefore difficult to ionize, such as SF 6 . However, this solution is complex to implement.
Un but de la présente invention est donc de pallier ces inconvénients, en proposant d'utiliser un matériau de contact électrique pour réaliser des plots de contact dont le fonctionnement n'est altéré ni à court terme, ni à long terme, par l'énergie d'un arc électrique.An object of the present invention is therefore to overcome these disadvantages, by proposing to use an electrical contact material to make contact pads whose operation is not impaired in the short term or in the long term by the energy an electric arc.
De manière plus précise, l'invention concerne l'utilisation d'un matériau comportant une matrice en métal conducteur et des entités magnétiques représentant entre 8 et 80% en poids du matériau et comprenant des phases magnétiques dures, lesdites entités magnétiques étant non aimantées et étant susceptibles d'être rendues aimantées avec une orientation moyenne, définie par la direction d'un champ magnétique appliqué sur ledit matériau, pour souffler un arc électrique entre deux plots de contacts électriques dont l'un au moins comprend ledit matériau, et ainsi réduire la durée de l'arc.More specifically, the invention relates to the use of a material comprising a matrix of conductive metal and magnetic entities representing between 8 and 80% by weight of the material and comprising hard magnetic phases, said magnetic entities being non-magnetized and being capable of being made magnetized with a mean orientation, defined by the direction of a magnetic field applied to said material, for blowing an electric arc between two pads of electrical contacts, at least one of which comprises said material, and thereby reducing the duration of the arc.
L'invention concerne également l'utilisation d'un matériau comportant une matrice en métal conducteur et des entités magnétiques représentant entre 8 et 80% en poids du matériau et comprenant des phases magnétiques dures, lesdites entités magnétiques initialement non aimantées ayant été rendues aimantées avec une orientation moyenne, définie par la direction d'un champ magnétique appliqué sur ledit matériau, pour souffler un arc électrique entre deux plots de contacts électriques dont l'un au moins comprend ledit matériau, et ainsi réduire la durée de l'arc.The invention also relates to the use of a material comprising a matrix of conductive metal and magnetic entities representing between 8 and 80% by weight of the material and comprising hard magnetic phases, said magnetic entities initially not magnetized having been made magnetized with an average orientation, defined by the direction of a magnetic field applied to said material, for blowing an electric arc between two pads of electrical contacts, at least one of which comprises said material, and thus reducing the duration of the arc.
En variante, le matériau peut comporter, en outre, une fraction réfractaire stable à une température supérieure à 900°C.Alternatively, the material may further comprise a stable refractory fraction at a temperature greater than 900 ° C.
D'une manière avantageuse, l'une au moins des phases des entités magnétiques est un composé magnétique dur à base de terres rares.Advantageously, at least one of the phases of the magnetic entities is a hard magnetic compound based on rare earths.
Pour permettre une utilisation selon l'invention, ledit matériau est capable de générer un champ d'induction magnétique, mesuré à sa surface, supérieur à 20 mT, de préférence supérieur à 60 mT, et plus préférentiellement supérieur à 100 mT.To enable use according to the invention, said material is capable of generating a magnetic induction field, measured at its surface, greater than 20 mT, preferably greater than 60 mT, and more preferably greater than 100 mT.
Des effets particulièrement remarquables sur l'extinction d'un arc électrique ont été observés pour une utilisation selon l'invention, selon laquelle lesdits plots définissent entre eux un axe, au moins l'un desdits plots étant réalisé dans ledit matériau et présentant une aimantation engendrant un champ magnétique perpendiculaire audit axe.Particularly remarkable effects on the extinction of an electric arc have been observed for use according to the invention, according to which said pads define between them an axis, at least one of said pads being made in said material and having a magnetization generating a magnetic field perpendicular to said axis.
D'une manière avantageuse, au moins l'un desdits plots qui comprend ledit matériau avec les entités magnétiques, présente une surcouche comprenant un matériau choisi parmi l'argent et le cuivre.Advantageously, at least one of said pads which comprises said material with the magnetic entities, has an overlayer comprising a material selected from silver and copper.
Selon un autre aspect, la présente invention concerne un matériau comportant une matrice en métal conducteur et des entités magnétiques représentant entre 8 et 80% en poids du matériau et comprenant des phases magnétiques dures, lesdites entités magnétiques étant non aimantées et susceptibles d'être rendues aimantées avec une orientation moyenne, définie par la direction d'un champ magnétique appliqué sur ledit matériau, l'une au moins des phases magnétiques étant un composé à base de terres rares, à l'exception du samarium.According to another aspect, the present invention relates to a material comprising a conductive metal matrix and magnetic entities representing between 8 and 80% by weight of the material and comprising phases magnetic resins, said magnetic entities being non-magnetized and capable of being magnetized with a mean orientation, defined by the direction of a magnetic field applied to said material, at least one of the magnetic phases being a land-based compound rare, with the exception of the samarium.
La présente invention concerne également un matériau comportant une matrice en métal conducteur et des entités magnétiques représentant entre 8 et 80% en poids du matériau et comprenant des phases magnétiques dures, lesdites entités magnétiques initialement non aimantées ayant été rendues aimantées avec une orientation moyenne, définie par la direction d'un champ magnétique appliqué sur ledit matériau, l'une au moins des phases magnétiques étant un composé à base de terres rares, à l'exception du samarium.The present invention also relates to a material comprising a matrix of conductive metal and magnetic entities representing between 8 and 80% by weight of the material and comprising hard magnetic phases, said magnetic entities initially not magnetized having been made magnetized with a mean orientation, defined by the direction of a magnetic field applied to said material, at least one of the magnetic phases being a compound based on rare earths, with the exception of the samarium.
Selon un autre aspect, la présente invention concerne un procédé de fabrication d'un plot de contact électrique comprenant les étapes suivantes:
- élaboration d'un matériau à partir d'argent ou de cuivre pour former la matrice dudit matériau et d'entités magnétiques comprenant des phases magnétiques dures, lesdites entités magnétiques étant non aimantées, l'une au moins des phases magnétiques étant un composé à base de terres rares,
- mise en forme du plot,
- assemblage sur un support, et
- aimantation du plot.
- developing a material from silver or copper to form the matrix of said material and magnetic entities comprising hard magnetic phases, said magnetic entities being non-magnetized, at least one of the magnetic phases being a compound based on rare earths,
- layout of the plot,
- assembly on a support, and
- magnetization of the stud.
Selon un autre aspect, l'invention concerne une paire de plots de contacts électriques, lesdits plots définissant entre eux un axe, caractérisée en ce que au moins l'un desdits plots est réalisé dans un matériau tel que défini ci-dessus et présente une aimantation engendrant un champ magnétique perpendiculaire audit axe.According to another aspect, the invention relates to a pair of pads of electrical contacts, said pads defining between them an axis, characterized in that at least one of said pads is made of a material as defined above and presents a magnetization generating a magnetic field perpendicular to said axis.
Dans le cas de courant continu, de très bons résultats ont aussi été observés pour une paire de plots de contacts électriques comprenant, à la cathode, un plot de contact réalisé dans un matériau défini ci-dessus.In the case of direct current, very good results have also been observed for a pair of electrical contact pads comprising, at the cathode, a contact pad made of a material defined above.
L'invention sera mieux comprise à la lecture de la description qui suit, faite en référence à la figure annexée, illustrant différentes orientations du champ magnétique présenté par les plots d'un contact électrique. Mode(s) de réalisation de l'inventionThe invention will be better understood on reading the description which follows, made with reference to the appended figure, illustrating different orientations of the magnetic field presented by the pads of an electrical contact. Mode (s) of realization of the invention
Le matériau de contact utilisé dans la présente invention est essentiellement constitué de:
- une matrice en métal conducteur, généralement en argent ou en cuivre ; et
- des entités magnétiques représentant entre 8 et 80% en poids du matériau et comprenant des phases magnétiques dures, lesdites entités magnétiques étant initialement non aimantées et susceptibles d'être aimantées, avec une orientation moyenne, définie par la direction d'un champ magnétique appliqué sur ledit matériau.
- a matrix of conductive metal, usually silver or copper; and
- magnetic entities representing between 8 and 80% by weight of the material and comprising hard magnetic phases, said magnetic entities being initially non-magnetized and capable of being magnetized, with a mean orientation, defined by the direction of a magnetic field applied to said material.
De ce fait, le matériau utilisé selon l'invention contient initialement des entités magnétiques multidomaines formant un ensemble initialement globalement non aimanté, et devant être ensuite aimanté par l'application d'un champ. De préférence, le matériau utilisé selon l'invention ne contient pas initialement d'entités spontanément aimantées monodomaines.As a result, the material used according to the invention initially contains multidomain magnetic entities forming a set initially initially unmagnetized, and then to be magnetized by the application of a field. Preferably, the material used according to the invention does not initially contain spontaneously magnetized monodomain entities.
De préférence, les entités magnétiques représentent entre 10 et 50% en poids du matériau, de préférence entre 12 et 30% en poids, et plus préférentiellement entre 18 et 22% en poids dudit matériau.Preferably, the magnetic entities represent between 10 and 50% by weight of the material, preferably between 12 and 30% by weight, and more preferably between 18 and 22% by weight of said material.
Les entités magnétiques comprennent des phases magnétiques qui peuvent être obtenues à partir d'un ou plusieurs composés ferromagnétiques ou ferrimagnétiques durs. Avantageusement, elles sont choisies parmi les composés à base de terres rares parmi lesquels on peut citer les composés dits de type RE-Fe-B, (RE étant l'abréviation anglaise de Rare Earth, Terre Rare). De préférence, RE est le néodyme ou le praséodyme. D'autres composés du type RE-M, peuvent être utilisés, RE étant de préférence La, Gd, Y ou Lu, de type 1/5, 1/7 ou 2/17, et M étant majoritairement Co ou Fe et pouvant contenir Cu, Zr, Al et d'autres éléments minoritaires. Les composés du type RE-Fe-N peuvent aussi être utilisés.Magnetic entities include magnetic phases that can be obtained from one or more ferromagnetic or ferrimagnetic hard compounds. Advantageously, they are chosen from compounds based on rare earths, among which mention may be made of the so-called RE-Fe-B type compounds (RE being the abbreviation of Rare Earth, Rare Earth). Preferably, RE is neodymium or praseodymium. Other compounds of the RE-M type can be used, RE being preferably La, Gd, Y or Lu, of the 1/5, 1/7 or 2/17 type, and M being predominantly Co or Fe and possibly containing Cu, Zr, Al and other minority elements. The compounds of the RE-Fe-N type can also be used.
D'autres composés tels que des ceux de la famille Pt(Fe,Co) peuvent aussi convenir, ou les composés du type ferrite de baryum ou de strontium.Other compounds such as those of the family Pt (Fe, Co) may also be suitable, or compounds of the ferrite type of barium or strontium.
D'autres matériaux peuvent encore être envisagés, l'essentiel étant que les entités magnétiques présentent un champ coercitif et une induction rémanente suffisants pour permettre leur utilisation dans les applications visées, ces deux paramètres pouvant être évalués par des essais expérimentaux simples. En effet, comme il sera expliqué ci-après, il est nécessaire que le contact génère un certain champ magnétique de manière à déstabiliser un éventuel arc électrique se produisant entre les plots. Il faut notamment que, après avoir lui-même été exposé à un champ magnétique, le matériau présente une induction rémanente suffisante et stable dans le temps, pour une utilisation à long terme. Cette induction, obtenue par aimantation des plots sous un champ magnétique extérieur, peut être caractérisée par le champ magnétique généré à la surface des plots, et persistant après suppression du champ magnétique appliqué. A titre indicatif, le champ généré à la surface doit être supérieur à 20 mT, de préférence à 60 mT, et plus préférentiellement supérieur à 100 mT, mesuré à l'aide d'une sonde à effet Hall distribuée par la société Lakeshore.Other materials can still be envisaged, the essential thing being that the magnetic entities have a coercive field and a residual induction sufficient to allow their use in the targeted applications, these two parameters can be evaluated by simple experimental tests. Indeed, as will be explained below, it is necessary that the contact generates a certain magnetic field so as to destabilize a possible electric arc occurring between the pads. In particular, it must be that after having been exposed to a magnetic field, the material has a sufficient and stable long-term residual induction for long-term use. This induction, obtained by magnetization of the pads under an external magnetic field, can be characterized by the magnetic field generated on the surface of the pads, and persistent after removal of the applied magnetic field. As an indication, the field generated on the surface must be greater than 20 mT, preferably 60 mT, and more preferably greater than 100 mT, measured using a Hall effect probe distributed by Lakeshore.
De manière facultative, la matrice comporte une fraction réfractaire, stable à une température supérieure à 900°C. La fraction réfractaire peut comporter l'un ou plusieurs des éléments choisis dans le groupe suivant: CdO, SnO2, ZnO, Bi2O3, C, WC, MgO, In2O3, ainsi que Ni, Fe, Mo, Zr, W ou leurs oxydes.Optionally, the matrix comprises a refractory fraction, stable at a temperature above 900 ° C. The refractory fraction may comprise one or more of the elements selected from the following group: CdO, SnO 2 , ZnO, Bi 2 O 3 , C, WC, MgO, In 2 O 3 , as well as Ni, Fe, Mo, Zr , W or their oxides.
La fraction réfractaire est ajoutée en quantité de manière à ce que le pourcentage des entités magnétiques soit d'au moins 8% et que la quantité de métal conducteur soit d'au moins 20%.The refractory fraction is added in an amount so that the percentage of magnetic entities is at least 8% and the amount of conductive metal is at least 20%.
De manière avantageuse, les entités magnétiques sont dispersées dans la matrice, soit de façon régulière, soit selon un gradient de concentration, soit, encore, en blocs localisés.Advantageously, the magnetic entities are dispersed in the matrix, either regularly, or according to a concentration gradient, or again in localized blocks.
En complément, le matériau peut aussi contenir des dopants ou des additifs mineurs, facilitant la mise en oeuvre du matériau, qui peuvent être par exemple, Ni, Co, Fe, Bi, Re, Zr et leurs oxydes.In addition, the material may also contain dopants or minor additives, facilitating the use of the material, which may be, for example, Ni, Co, Fe, Bi, Re, Zr and their oxides.
Le matériau décrit ci-dessus est utilisé pour réaliser des plots de contacts électriques. Les premières étapes du procédé d'élaboration du matériau et de mise en forme des plots de contacts sont courantes et sont connues de l'homme du métier qui pourra choisir entre plusieurs techniques. En outre, le procédé comporte une étape supplémentaire d'aimantation du matériau sur les plots déjà élaborés.The material described above is used to make pads of electrical contacts. The first steps of the process of developing the material and forming the contact pads are common and are known to those skilled in the art who can choose between several techniques. In addition, the method comprises an additional step of magnetizing the material on the already developed pads.
En particulier, et sans qu'il soit besoin de le détailler davantage pour l'homme du métier qui pourra, moyennant quelques essais de pratique courante, mettre en oeuvre les techniques ci-après, l'élaboration du matériau utilisé selon l'invention pourra être réalisée par:
- métallurgie des poudres,
- voie chimique de précipitation de sels en solution,
- atomisation,
- dépôt de couche mince ou épaisse, ou
- extrusion à partir d'une billette ou d'un mélange de poudres.
- powder metallurgy,
- chemical way of precipitation of salts in solution,
- atomization,
- Thin or thick layer deposition, or
- extrusion from a billet or a mixture of powders.
Avantageusement, l'étape d'élaboration du matériau peut être réalisée par métallurgie des poudres, l'une des entités magnétiques étant du RE-Fe-B nanostructuré, où RE est un élément des terres rares.Advantageously, the material preparation step may be carried out by powder metallurgy, one of the magnetic entities being nanostructured RE-Fe-B, where RE is a rare earth element.
Une direction privilégiée des entités magnétiques pourra être obtenue par application d'un procédé approprié lors de l'élaboration des plots (pression, champ magnétique, traitement thermique). Cette opération n'est pas indispensable mais elle permet d'augmenter l'aimantation des plots induite par le champ, appliqué après élaboration des plots.A preferred direction of the magnetic entities may be obtained by applying a suitable method during the development of the pads (pressure, magnetic field, heat treatment). This operation is not essential but it makes it possible to increase the magnetization of the studs induced by the field, applied after elaboration of the pads.
Il est à noter que, de manière non limitative, l'utilisation, comme matériau de départ pour constituer les entités magnétiques du contact, d'un ruban nanostructuré de RE-Fe-B obtenu par une technique de solidification rapide, particulièrement par la technique connue sous le nom de melt spinning donne d'excellents résultats. Il n'est pas nécessaire de décrire davantage cette technique connue de l'homme du métier. On retiendra, en résumé, qu'elle consiste à faire couler, à travers une buse, du métal en fusion contenu dans un réservoir, et à amener un filet de métal liquide au contact d'un cylindre, en cuivre par exemple, tournant à grande vitesse. Grâce à cette technique, le RE-Fe-B refroidit en prenant une microstructure, qui lui permet de présenter des caractéristiques magnétiques dures remarquables en vue de l'utilisation visée.It should be noted that, in a nonlimiting manner, the use, as a starting material for constituting the magnetic entities of the contact, of a nanostructured tape of RE-Fe-B obtained by a rapid solidification technique, particularly by the technique known as melt spinning gives excellent results. It is not necessary to further describe this technique known to those skilled in the art. In summary, it consists in flowing, through a nozzle, molten metal contained in a reservoir, and in bringing a net of liquid metal in contact with a cylinder, for example copper, rotating great speed. Thanks to this technique, the RE-Fe-B cools by taking a microstructure, which allows it to present remarkable hard magnetic characteristics for the intended use.
Le RE-Fe-B peut être associé à d'autres matériaux magnétiques pour optimiser les propriétés magnétiques de l'ensemble, le RE-Fe-B représentant avantageusement, au moins 50% en poids des entités magnétiques.The RE-Fe-B can be combined with other magnetic materials to optimize the magnetic properties of the assembly, the RE-Fe-B advantageously representing at least 50% by weight of the magnetic entities.
Des plots de contact sont ensuite mis en forme par découpe de bandes, estampage de fils, compression unitaire. Ils sont ensuite disposés sur un support adapté, par toute méthode traditionnelle d'assemblage de contacts électriques, en particulier : soudage par résistance, brasage par résistance, brasage par induction, brasage à la flamme ou au four, sertissage, incrustation... en vue de leur utilisation comme contacts électriques.Contact pads are then shaped by cutting strips, stamping son, unit compression. They are then arranged on a suitable support, by any traditional method of assembling electrical contacts, in particular: resistance welding, resistance brazing, induction brazing, flame or oven brazing, crimping, incrustation ... view of their use as electrical contacts.
En variante, le matériau utilisé selon l'invention peut être mis sous forme d'une rondelle ou d'une couche, formant un système magnétique, rendue solidaire d'un plot de contact électrique traditionnel par incrustation, soudage, brasage ou rivetage, voire par dépôt de couche(s). Dans ce dernier cas, le matériau magnétique, le matériau de contact ou les deux peuvent se présenter sous forme d'une ou de plusieurs couches. Le système magnétique peut également servir de support mécanique et d'amenée de courant au contact électrique. Il est avantageusement possible d'adapter le système magnétique selon la variante dans des installations existantes, en conservant le matériau de contact initial, car il n'occupe qu'une faible place en plus du contact, à la différence des organes électromagnétiques de l'art antérieur.Alternatively, the material used according to the invention can be formed into a washer or a layer, forming a magnetic system, made integral with a traditional electrical contact pad by incrustation, welding, brazing or riveting, or by layer deposition (s). In the latter case, the magnetic material, the contact material or both may be in the form of one or more layers. The magnetic system can also serve as a mechanical support and supply current to the electrical contact. It is advantageously possible to adapt the magnetic system according to the variant in existing installations, while retaining the initial contact material, since it occupies only a small space in addition to the contact, unlike the electromagnetic members of the prior art.
Dans les plots mis en forme, les entités magnétiques ne sont pas aimantées. Les plots doivent ensuite subir l'étape d'aimantation par l'application d'un champ magnétique aimanteur pour procurer aux entités magnétiques non aimantées une aimantation globale selon une orientation moyenne définie par le champ appliqué. Les plots peuvent alors jouer pleinement leur rôle de souffleur ou d'extincteur d'arc. Cette opération peut avoir lieu en usine, après élaboration du plot. Elle peut aussi avoir lieu chez l'utilisateur, avant ou après le montage final du contact. Elle est réalisée en exposant les plots à un champ magnétique d'une intensité comprise entre 0,5 et 30 T, de préférence entre 1 et 30 T, et plus préférentiellement encore entre 1 et 10 T. Ainsi, conformément à l'invention, le matériau utilisé sous forme de plots comprend des entités magnétiques initialement non aimantées qui sont soit susceptibles d'être rendues aimantées par l'application d'un champ magnétique chez l'utilisateur, soit déjà rendues aimantées par l'application d'un champ magnétique en usine.In the shaped pads, the magnetic entities are not magnetized. The pads must then undergo the magnetization step by applying a magnetizing magnetic field to provide the magnetic non-magnetized entities global magnetization in a mean orientation defined by the applied field. The studs can then fully play their role of blower or arc extinguisher. This operation can take place in the factory, after development of the stud. It can also take place at the user, before or after the final assembly of the contact. It is performed by exposing the pads to a magnetic field of an intensity of between 0.5 and 30 T, preferably between 1 and 30 T, and even more preferably between 1 and 10 T. Thus, according to the invention, the material used in the form of pads comprises initially unmagnetized magnetic entities that are either susceptible to being magnetized by the application of a magnetic field to the user, or already magnetized by the application of a magnetic field in the factory.
Par cette application d'un champ magnétique de direction et d'intensité appropriées, sur les plots déjà élaborés, une aimantation globale des plots est créée, dont l'orientation est définie par le champ appliqué. Il en résulte qu'un champ magnétique est généré dans l'environnement du plot. Ce champ agit sur l'arc de coupure et contribue à son soufflage.By this application of a magnetic field of appropriate direction and intensity, on the already developed pads, a global magnetization of the pads is created, whose orientation is defined by the applied field. As a result, a magnetic field is generated in the environment of the pad. This field acts on the arc of cutoff and contributes to its blowing.
Le champ peut notamment être appliqué parallèlement ou de préférence perpendiculairement à l'axe longitudinal d'un plot, de manière à ce que ce dernier présente des lignes de champs telles qu'illustrées, respectivement, sur les
Les plots ainsi obtenus sont ensuite mis en oeuvre dans des contacts électriques formés de deux plots définissant entre eux un premier axe. Le contact peut ne comporter qu'un seul plot obtenu selon le procédé ci-dessus, disposé dans le cas d'un circuit en courant continu, à l'anode ou à la cathode. Il est également possible que les deux plots formant le contact soient réalisés dans un matériau magnétique utilisé selon l'invention. Diverses orientations de champ magnétiques sont possibles et envisageables, par exemple, lorsqu'un seul plot aimanté est utilisé, le champ qu'il génère peut être orienté parallèlement ou perpendiculairement au premier axe.The pads thus obtained are then implemented in electrical contacts formed of two pads defining between them a first axis. The contact may comprise a single pad obtained according to the above method, arranged in the case of a DC circuit, the anode or the cathode. It is also possible that the two studs forming the contact are made of a magnetic material used according to the invention. Various magnetic field orientations are possible and conceivable, for example, when a single magnetic pad is used, the field it generates can be oriented parallel or perpendicular to the first axis.
En variante, le plot peut comprendre une surcouche déposée sur le matériau magnétique. Une telle surcouche comprend un matériau conducteur choisi parmi l'argent et le cuivre et éventuellement un composé réfractaire choisi dans le groupe comprenant les composés CdO, SnO2, ZnO, Bi2O3, C, WC, MgO, In2O3, ainsi que Ni, Fe, Mo, Zr, W ou leurs oxydes.Alternatively, the stud may comprise an overlay deposited on the magnetic material. Such an overcoat comprises a conductive material chosen from silver and copper and optionally a refractory compound chosen from the group comprising compounds CdO, SnO 2 , ZnO, Bi 2 O 3 , C, WC, MgO, In 2 O 3 , as well as Ni, Fe, Mo, Zr, W or their oxides.
Cette surcouche permet avantageusement d'isoler les entités magnétiques du plot de la surface de contact et ainsi de diminuer les risques de soudure à la fermeture. En effet, l'effet de soufflage peut être atténué par l'ionisation des éléments constitutifs du composé magnétique, ce dernier pouvant augmenter la résistance de contact et favoriser la soudure. De toute manière, l'extrême surface du contact est fortement chauffée sous l'effet de l'arc si bien que les propriétés magnétiques des entités superficielles sont généralement détruites en fonctionnement. La surcouche doit être suffisamment mince pour que le champ crée par les entités magnétiques sous-jacentes dans la zone de l'arc reste suffisamment intense, et éventuellement suffisamment épaisse pour ne pas être complètement fondue sous l'effet de l'arc. Toutefois, il s'avère que la réduction de la durée de l'arc obtenue selon l'invention conduit à une érosion très faible. Ainsi, la surcouche peut présenter une épaisseur comprise entre 0,05 mm et 3 mm, de préférence comprise entre 0,1 mm et 2 mm, et plus préférentiellement comprise entre 0,2 mm et 1 mm.This overlay advantageously makes it possible to isolate the magnetic entities from the stud of the contact surface and thus to reduce the risks of soldering on closing. Indeed, the blowing effect can be attenuated by the ionization of the constituent elements of the magnetic compound, the latter can increase the contact resistance and promote welding. In any case, the extreme surface of the contact is strongly heated under the effect of the arc so that the magnetic properties of the surface entities are generally destroyed in operation. The overlayer must be thin enough so that the field created by the underlying magnetic entities in the arc area remains sufficiently intense, and possibly thick enough not to be completely melted under the effect of the arc. However, it turns out that the reduction in the duration of the arc obtained according to the invention leads to very low erosion. Thus, the overlay may have a thickness of between 0.05 mm and 3 mm, preferably between 0.1 mm and 2 mm, and more preferably between 0.2 mm and 1 mm.
Les exemples suivants illustrent la présente invention sans toutefois en limiter la portée.The following examples illustrate the present invention without, however, limiting its scope.
Exemple 1Example 1
L'élaboration du matériau se fait par métallurgie des poudres. Ainsi, un ruban de Nd-Fe-B produit par la technique connue sous le nom de "melt spinning" est réduit en poudre, sous argon, par broyage à boulet, jusqu'à obtention d'une granulométrie comprise entre 1 et 50 µm. La durée de cette opération est d'environ 5h.The elaboration of the material is done by metallurgy of the powders. Thus, a ribbon of Nd-Fe-B produced by the technique known as "melt spinning" is reduced to powder, under argon, by ball milling, until a particle size of between 1 and 50 μm is obtained. . The duration of this operation is about 5h.
La poudre ainsi obtenue est mélangée à de l'argent en poudre, dont les particules présentent un diamètre moyen compris entre 15 et 50 µm. Le mélange est réalisé dans une proportion massique de 80% d'argent et 20% de poudre d'entités magnétiques EM. On obtient un matériau magnétique, constitutif d'un plot de contact électrique.The powder thus obtained is mixed with powdered silver, the particles of which have a mean diameter of between 15 and 50 μm. The mixture is produced in a mass proportion of 80% of silver and 20% EM magnetic entity powder. A magnetic material is obtained constituting an electrical contact pad.
Un plot de contact électrique est ensuite mis en forme par compression unitaire et compacté sous une pression de 700MPa.An electrical contact pad is then shaped by unitary compression and compacted under a pressure of 700 MPa.
Puis le plot est fritté sous vide à 400°C pendant environ 30 minutes.The pad is then sintered under vacuum at 400 ° C for about 30 minutes.
Le plot est ensuite assemblé sur un support selon l'une des techniques mentionnées ci-dessus, pour être utilisé dans un contact électrique.The pad is then assembled on a support according to one of the techniques mentioned above, for use in an electrical contact.
Enfin, le plot est aimanté en l'exposant à un champ magnétique de 8 T. Le plot est orienté perpendiculairement au champ magnétique, tel qu'illustré sur la
Le plot obtenu ci-dessus est ensuite utilisé dans un contact d'un circuit électrique de type résistif, fonctionnant sous une tension continue de 42 V, avec une intensité de 37,5 A. A titre d'exemple, seul un plot aimanté est disposé à la cathode, l'autre étant en argent.The pad obtained above is then used in a contact of a resistive-type electrical circuit, operating under a 42 V DC voltage, with an intensity of 37.5 A. For example, only a magnet pad is disposed at the cathode, the other being silver.
Avec cette configuration (aimantation perpendiculaire, un seul plot aimanté à la cathode), on mesure la durée d'arc d'ouverture. Des essais de fermeture sont également réalisés pour simuler les risques de soudage, dans les mêmes conditions que pour l'ouverture, mais avec un courant de 90 A. On mesure le pourcentage de soudage obtenu, dont la force de rupture est supérieure à 0,1 N.With this configuration (perpendicular magnetization, a single magnetic pad at the cathode), the opening arc duration is measured. Closing tests are also performed to simulate the risks of welding, under the same conditions as for the opening, but with a current of 90 A. The percentage of welding obtained, whose breaking force is greater than 0, is measured. 1 N.
Les résultats obtenus sont reportés dans le tableau 1 ci-dessous.The results obtained are reported in Table 1 below.
Exemple 2Example 2
L'exemple 1 est reproduit en remplaçant 6% en poids d'argent de la matrice par 6% en poids d'un composé réfractaire (SnO2).Example 1 is reproduced by replacing 6% by weight of silver of the matrix with 6% by weight of a refractory compound (SnO 2 ).
Les mêmes tests que pour l'exemple 1 sont réalisés. Les résultats obtenus sont reportés dans le tableau 1 ci-dessous.The same tests as for example 1 are carried out. The results obtained are reported in Table 1 below.
Exemple 3Example 3
Une surcouche de 0,6 mm d'épaisseur est appliquée sur le matériau magnétique du plot obtenu dans l'exemple 1. Ladite surcouche comprend 100% d'argent.An overlayer 0.6 mm thick is applied to the magnetic material of the pad obtained in Example 1. Said overlayer comprises 100% silver.
Les mêmes tests que pour l'exemple 1 sont réalisés. Les résultats obtenus sont reportés dans le tableau 1 ci-dessous.The same tests as for example 1 are carried out. The results obtained are reported in Table 1 below.
Exemples 4-6Examples 4-6
A titre comparatif, l'exemple 1 est reproduit en ne soumettant pas le plot à une aimantation (exemple 4) ou en utilisant d'autres matériaux pour réaliser les plots du contact (exemples 5 et 6).For comparison, Example 1 is reproduced by not subjecting the pad to a magnetization (Example 4) or by using other materials to make the pads of the contact (Examples 5 and 6).
Les mêmes tests que pour l'exemple 1 sont réalisés. La composition de ces matériaux ainsi que les résultats obtenus avec les plots élaborés sont reportés dans le tableau 1 ci-dessous:
Les résultats du Tableau 1 montrent que l'utilisation selon l'invention du matériau magnétique décrit ci-dessus pour réaliser des plots de contacts électriques permet de réduire la durée d'arc à l'ouverture de 9 ms, voire 24 ms à 3 ms. L'exemple 4 montre également l'importance de l'étape d'aimantation du plot puisqu'un contact comprenant un plot non aimanté présente une durée d'arc à l'ouverture de 9 ms alors que le contact comprenant le plot aimanté présente une durée d'arc à l'ouverture de 3 ms.The results of Table 1 show that the use according to the invention of the magnetic material described above for making electrical contact pads makes it possible to reduce the arc duration at the opening of 9 ms, or even 24 ms at 3 ms. . Example 4 also shows the importance of the magnetization step of the stud since a contact comprising a non-magnetized stud has an arc duration at the opening of 9 ms while the contact comprising the magnetic pin has a arc duration at opening of 3 ms.
De plus, l'ajout d'un composé réfractaire (exemple 2) ou l'utilisation d'une surcouche (exemple 3) permet de réduire fortement la tendance au soudage des plots constitué du matériau magnétique défini ci-dessus sans affecter significativement la durée d'arc à l'ouverture. L'utilisation d'une surcouche permet d'obtenir des résultats particulièrement intéressants.In addition, the addition of a refractory compound (Example 2) or the use of an overlayer (Example 3) makes it possible to greatly reduce the tendency of the studs to be welded, consisting of the magnetic material defined above without significantly affecting the duration from bow to opening. The use of an overlay makes it possible to obtain particularly interesting results.
Claims (21)
Priority Applications (16)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP08156731A EP2124236A1 (en) | 2008-05-22 | 2008-05-22 | Use of an electric contact material to blow an electric arc |
ES09749760T ES2380310T3 (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material to blow an electric arc |
PCT/EP2009/055879 WO2009141270A1 (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc |
AT09749760T ATE545144T1 (en) | 2008-05-22 | 2009-05-14 | USING AN ELECTRICAL CONTACT MATERIAL TO BLOW AN ELECTRIC ARC |
CA2723770A CA2723770A1 (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc |
CN2009801183666A CN102037530A (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc |
BRPI0913030A BRPI0913030A2 (en) | 2008-05-22 | 2009-05-14 | Using an electrical contact material to blow an electric arc |
EP09749760A EP2297757B1 (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc |
PL09749760T PL2297757T3 (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc |
JP2011509934A JP2011521418A (en) | 2008-05-22 | 2009-05-14 | Use of electrical contact materials for electric arc blowout |
SI200930226T SI2297757T1 (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc |
PT09749760T PT2297757E (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc |
MX2010012523A MX2010012523A (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc. |
US12/992,308 US20110068088A1 (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc |
IL209303A IL209303A0 (en) | 2008-05-22 | 2010-11-14 | Use of an electrical contact material for blowing out an electric arc |
HK11105874.7A HK1152146A1 (en) | 2008-05-22 | 2011-06-10 | Use of an electrical contact material for blowing an electric arc |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP08156731A EP2124236A1 (en) | 2008-05-22 | 2008-05-22 | Use of an electric contact material to blow an electric arc |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2124236A1 true EP2124236A1 (en) | 2009-11-25 |
Family
ID=39855341
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP08156731A Withdrawn EP2124236A1 (en) | 2008-05-22 | 2008-05-22 | Use of an electric contact material to blow an electric arc |
EP09749760A Active EP2297757B1 (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP09749760A Active EP2297757B1 (en) | 2008-05-22 | 2009-05-14 | Use of an electrical contact material for blowing an electric arc |
Country Status (15)
Country | Link |
---|---|
US (1) | US20110068088A1 (en) |
EP (2) | EP2124236A1 (en) |
JP (1) | JP2011521418A (en) |
CN (1) | CN102037530A (en) |
AT (1) | ATE545144T1 (en) |
BR (1) | BRPI0913030A2 (en) |
CA (1) | CA2723770A1 (en) |
ES (1) | ES2380310T3 (en) |
HK (1) | HK1152146A1 (en) |
IL (1) | IL209303A0 (en) |
MX (1) | MX2010012523A (en) |
PL (1) | PL2297757T3 (en) |
PT (1) | PT2297757E (en) |
SI (1) | SI2297757T1 (en) |
WO (1) | WO2009141270A1 (en) |
Families Citing this family (2)
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CN103551575A (en) * | 2013-10-31 | 2014-02-05 | 福达合金材料股份有限公司 | Preparation method of soft magnetic electrical contact material with self-arc-quenching characteristic and product obtained by same |
CN113194590B (en) * | 2021-04-20 | 2023-03-14 | 核工业西南物理研究院 | Electrostatic probe head |
Citations (3)
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DE857252C (en) * | 1950-06-08 | 1952-11-27 | Siemens Ag | Arrangement of switching contacts, especially of temperature regulators |
US3626124A (en) | 1969-11-17 | 1971-12-07 | Peter A Denes | Arc and spark extinguishing contacts utilizing single domain magnetic particles |
EP1482525A2 (en) | 2003-05-26 | 2004-12-01 | Omron Corporation | Contact construction for DC loads and switching device having the contact construction |
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US3641298A (en) * | 1967-07-19 | 1972-02-08 | Mallory & Co Inc P R | Electrically conductive material and electrical contact |
JPS60162351U (en) * | 1984-04-05 | 1985-10-28 | オムロン株式会社 | electromagnetic relay |
DE4117311A1 (en) * | 1991-05-27 | 1992-12-03 | Siemens Ag | CONTACT MATERIAL ON A SILVER BASE FOR USE IN SWITCHGEAR DEVICES IN ENERGY TECHNOLOGY |
US5233143A (en) * | 1991-11-06 | 1993-08-03 | The United States Of America As Represented By The Secretary Of The Navy | High-power gas switch with hydride electrodes |
JPH0668735A (en) * | 1992-08-20 | 1994-03-11 | Daido Steel Co Ltd | Electric contact |
JPH0773767A (en) * | 1993-09-06 | 1995-03-17 | Daido Steel Co Ltd | Electrical contact |
US5578885A (en) * | 1994-12-22 | 1996-11-26 | General Motors Corporation | Rotor assembly for hybrid alternator |
KR100332513B1 (en) * | 1998-08-21 | 2002-04-13 | 니시무로 타이죠 | Contact material for vacuum valve and method for fabricating the same |
JP2002294384A (en) * | 2001-03-28 | 2002-10-09 | Toshiba Corp | Electrical contact material |
JP3795830B2 (en) * | 2002-04-26 | 2006-07-12 | 株式会社日立製作所 | AC generator for vehicles |
EP1381065A1 (en) * | 2002-07-12 | 2004-01-14 | Metalor Technologies International S.A. | Electrical contact material and its method of manufacture |
JP2004288605A (en) * | 2003-03-04 | 2004-10-14 | Sumitomo Electric Ind Ltd | Direct current relay |
US7553561B2 (en) * | 2004-07-16 | 2009-06-30 | Tdk Corporation | Rare earth magnet |
JP4565338B2 (en) * | 2005-11-30 | 2010-10-20 | アイシン精機株式会社 | Permanent magnet fixing structure and fixing method |
-
2008
- 2008-05-22 EP EP08156731A patent/EP2124236A1/en not_active Withdrawn
-
2009
- 2009-05-14 AT AT09749760T patent/ATE545144T1/en active
- 2009-05-14 BR BRPI0913030A patent/BRPI0913030A2/en not_active Application Discontinuation
- 2009-05-14 CN CN2009801183666A patent/CN102037530A/en active Pending
- 2009-05-14 ES ES09749760T patent/ES2380310T3/en active Active
- 2009-05-14 JP JP2011509934A patent/JP2011521418A/en active Pending
- 2009-05-14 WO PCT/EP2009/055879 patent/WO2009141270A1/en active Application Filing
- 2009-05-14 PT PT09749760T patent/PT2297757E/en unknown
- 2009-05-14 CA CA2723770A patent/CA2723770A1/en not_active Abandoned
- 2009-05-14 MX MX2010012523A patent/MX2010012523A/en active IP Right Grant
- 2009-05-14 PL PL09749760T patent/PL2297757T3/en unknown
- 2009-05-14 SI SI200930226T patent/SI2297757T1/en unknown
- 2009-05-14 US US12/992,308 patent/US20110068088A1/en not_active Abandoned
- 2009-05-14 EP EP09749760A patent/EP2297757B1/en active Active
-
2010
- 2010-11-14 IL IL209303A patent/IL209303A0/en unknown
-
2011
- 2011-06-10 HK HK11105874.7A patent/HK1152146A1/en unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE857252C (en) * | 1950-06-08 | 1952-11-27 | Siemens Ag | Arrangement of switching contacts, especially of temperature regulators |
US3626124A (en) | 1969-11-17 | 1971-12-07 | Peter A Denes | Arc and spark extinguishing contacts utilizing single domain magnetic particles |
EP1482525A2 (en) | 2003-05-26 | 2004-12-01 | Omron Corporation | Contact construction for DC loads and switching device having the contact construction |
Also Published As
Publication number | Publication date |
---|---|
PT2297757E (en) | 2012-04-18 |
HK1152146A1 (en) | 2012-02-17 |
ATE545144T1 (en) | 2012-02-15 |
JP2011521418A (en) | 2011-07-21 |
WO2009141270A1 (en) | 2009-11-26 |
CA2723770A1 (en) | 2009-11-26 |
EP2297757A1 (en) | 2011-03-23 |
US20110068088A1 (en) | 2011-03-24 |
PL2297757T3 (en) | 2012-07-31 |
BRPI0913030A2 (en) | 2015-10-13 |
IL209303A0 (en) | 2011-01-31 |
SI2297757T1 (en) | 2012-08-31 |
MX2010012523A (en) | 2011-02-22 |
ES2380310T3 (en) | 2012-05-10 |
EP2297757B1 (en) | 2012-02-08 |
CN102037530A (en) | 2011-04-27 |
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