High-voltage interrupter chamber

Abstract

The invention relates to a high-voltage interrupter chamber (10) having a vertical main axis A and comprising two fixed contacts (18), offset with respect to each other in a transverse direction perpendicular to the main axis A, and a movable contact (20), wherein the movable contact (20) is mounted so as to be translatably movable with respect to the fixed contacts (18) between a closed position and an open position, the interrupter chamber (10) further comprising permanent magnets (28, 30) that are distributed on either side of the fixed contacts (18) and the movable contact (20), characterised in that it comprises a screen (34) made of an electrically insulating material, which is arranged between the fixed contacts (18).

Description

[0001] Description

[0002] Title: HIGH VOLTAGE CUTTING CHAMBER

[0003] TECHNICAL FIELD

[0004] The invention relates to a moving contact arc cutting chamber which is designed to improve the quality of breaking an electric arc.

[0005] STATE OF THE PRIOR ART

[0006] A double-point breaking chamber has two fixed contacts which are each connected to a terminal of the breaking chamber and a moving contact.

[0007] The moving contact is movable in movement in the breaking chamber between a position for connecting the fixed contacts, in which it is simultaneously in contact with the two fixed contacts, and an isolation position in which the moving contact is located at a distance from the two fixed contacts.

[0008] When the arc chute opens, the breaking of the electrical contact between the moving contact and each fixed contact produces electric arcs.

[0009] To limit the formation of these electric arcs, the arc chute has permanent magnets distributed around the fixed contacts. The magnetic field generated by these magnets interacts with the electric arc to move it under the action of the Laplace force.

[0010] There are two types of arc chutes, depending on whether the moving contact moves in rotation or in translation.

[0011] In the second type of breaking chamber, for which the moving contact moves in translation, the fixed contacts are carried by the same support plate and are therefore arranged on the same side of the moving contact.

[0012] According to this embodiment, the magnets are arranged longitudinally and transversely on either side of the contacts, relative to the main axis of translation of the movable contact.

[0013] The magnets are thus located far from each other, which means that the resulting magnetic field is weak in the center of the arc chute. In this case, if an electric arc forms at the center of the arc chute, the breaking efficiency is limited at this level, there is also a risk that the electric arc will catch on the translation axis and then cause a short circuit between the two fixed contacts.

[0014] The aim of the invention is to propose an improved arc cutting chamber making it possible to improve the breaking of electric arcs forming near the central axis.

[0015] STATEMENT OF THE INVENTION

[0016] The invention provides a high-voltage breaking chamber having a vertical main axis A and comprising two fixed contacts offset from each other in a transverse direction perpendicular to the main axis A and a movable contact, in which the movable contact is mounted movable in translation relative to the fixed contacts in the direction of the main axis A between a closed position in which the movable contact is simultaneously in electrical contact with the two fixed contacts and an open position in which the movable contact is located axially at a distance from the two fixed contacts, the breaking chamber further comprising first permanent magnets and second permanent magnets which are distributed longitudinally or transversely on either side of the fixed contacts and the movable contact, characterized in that it comprises a screen made of an electrically insulating material, which is arranged between the fixed contacts.

[0017] Preferably, the screen is integral with the movable contact in translation relative to the fixed contacts.

[0018] Preferably, the longitudinal dimension of the screen is greater than the longitudinal dimension of the fixed contacts and the screen projects longitudinally at its two longitudinal ends relative to the fixed contacts.

[0019] Preferably, the vertical dimension of the screen is greater than a vertical clearance between the movable contact and each fixed contact when the movable contact is in the open position and the screen projects vertically downwards and upwards relative to this vertical clearance. Preferably, the screen carries two third permanent magnets which are arranged transversely between the fixed contacts.

[0020] Preferably, the cutting chamber comprises a guide rod providing guidance of the movable contact in translation and the screen is guided in translation by the guide rod.

[0021] Preferably, every third permanent magnet is arranged transversely between the guide rod and a fixed contact.

[0022] Preferably, the first permanent magnets are arranged longitudinally on either side of the fixed contacts.

[0023] Preferably, the second permanent magnets are arranged transversely on either side of the fixed contacts.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS

[0025] [Fig. 1] is a schematic representation in top view of an arc chute according to the invention.

[0026] [Fig. 2] is a sectional view along plane AA of the interrupting chamber shown in Figure 1.

[0027] [Fig. 3] is a sectional view along plane BB of the interrupting chamber shown in Figure 1.

[0028] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0029] For the description of the invention, the vertical, longitudinal and transverse orientations according to the reference V, L, T indicated in the figures will be adopted without limitation.

[0030] The figures show an extinguishing chamber 10 for a high-voltage circuit, which makes it possible to break the flow of electric current within a circuit.

[0031] Preferably, an installation comprises several similar breaking chambers 10 arranged in parallel, each of which is associated with an electrical conductor.

[0032] In the following description, reference will be made to a single arc chute. It will be understood that this description will apply identically to any other arc chute.

[0033] 10. The arc extinguishing chamber 10 comprises a body 12 made of an electrically insulating material. It delimits a volume 14 filled with a dielectric gas promoting the extinction of arcs. Preferably, the dielectric gas is air but it will be understood that it may be any other dielectric gas capable of performing the arc extinguishing function.

[0034] The cutting chamber 10 has a symmetry along a vertical main axis A, which is central to it.

[0035] The body 12 comprises a horizontal support plate 16 which carries two fixed contacts 18, each of which is connected to a terminal of the breaking chamber 10. The two terminals of the breaking chamber 10 (not shown) are in turn connected to two electrical conductors which the breaking chamber 10 is intended to connect.

[0036] Here, the two fixed contacts 18 are offset from each other in the transverse direction and they are located at a distance from each other allowing them to be electrically isolated.

[0037] The extinguishing chamber 10 also comprises a movable contact 20 made of an electrically conductive material. The movable contact 20 is intended to electrically connect, or not, the two fixed contacts 18 to electrically connect the two electrical conductors associated with the extinguishing chamber 10.

[0038] The movable contact 20 is mounted to move in translation in the body 12 in the vertical direction between an open position shown in the figures in which the movable contact 20 is located vertically at a distance from the two fixed contacts 18 and a closed position not shown in which the movable contact 20 is simultaneously in contact with the two fixed contacts 18.

[0039] Here, the movable contact 20 is located vertically below the fixed contacts 18, the movement of the movable contact 20 from the open position to the closed position consists of an upward translation of the movable contact 20. It will be understood that the invention is not limited to this embodiment and that according to variants, the movable contact can be offset longitudinally and / or transversely or be located vertically above the fixed contacts 18 without departing from the invention. The breaking chamber 10 also comprises means (not shown) for driving the movable contact to move towards the open position or towards the closed position, depending on whether the movable contact is in one or the other of these two positions.

[0040] The body 12 also carries a guide rod 22 for the movable contact 20 in vertical translation. According to a preferred but non-limiting embodiment, the guide rod 22 is coaxial with the main axis A.

[0041] The guide rod 22 here extends vertically downwards from the support plate 16. The guide rod 22 is further made of an electrically conductive metallic material.

[0042] The movable contact 20 comprises a central orifice coaxial with the main axis A, in which the guide rod 22 is received.

[0043] During an opening phase of the breaking chamber 10, to cut off the flow of electric current in the electrical conductor, the movable contact 20 is moved in translation vertically downwards. Following this translation, the electrical contact between each fixed contact 18 and the movable contact 20 is broken.

[0044] An electric arc then forms between the moving contact 20 and a fixed contact 18 or the two fixed contacts 18.

[0045] Each fixed contact 18 comprises a contact pad 24 intended to come into electrical contact with the movable contact 20 and the movable contact 20 also comprises two contact pads 26, each of which is intended to come into contact with a contact pad 24 of a fixed contact 18 when the movable contact 20 is in the closed position. It is between the contact pads 24, 26 of each of the movable contact 20 and of a fixed contact 18 that the electric arc is intended to form.

[0046] The contact pads 24, 26 are made of an electrically conductive material which is less prone to deterioration under the action of the electric arc.

[0047] The material constituting the contact pads 24, 26 is further chosen to promote the mobility of the arc feet, that is to say it promotes the movement of the transition zone between the pad and the rest of the arc. The mobility of the arc foot has an impact on the speed of movement of the electric arc towards an area designed to promote the extinction of the arc. The arc breaking chamber 10 also comprises means for extinguishing the electric arcs which form when the moving contact 20 separates from the fixed contacts 18.

[0048] These extinguishing means comprise the dielectric gas, that is to say air here, which fills the volume 14 of the body 12 and permanent magnets 28, 30 which are distributed longitudinally and transversely around the fixed contacts 18 and the movable contact 20.

[0049] Two first permanent magnets 28 are arranged longitudinally on either side and at a distance from the contacts 18, 20. Two second permanent magnets 30 are arranged transversely on either side and at a distance from the contacts 18, 20.

[0050] The first permanent magnets 28 and the second permanent magnets 30 are fixed to the body 12. Their vertical dimension and their vertical position are defined so that an upper end of each permanent magnet is located vertically above the fixed contacts 18 and a lower end of each permanent magnet 28, 30 is located vertically below the movable contact 20 when the movable contact 20 is in its open position, that is to say its vertically lower position.

[0051] These first permanent magnets 28 and second permanent magnets 30 are arranged in the breaking chamber 10 to generate magnetic fields which are oriented vertically in the areas where the electric arcs occur. These resulting magnetic fields then exert on the electric arcs an electromagnetic force, called Laplace force, which drives each electric arc towards a breaking zone 32.

[0052] Since the permanent magnets 28, 30 are arranged longitudinally and transversely at a distance from the main axis A, the intensity of the Laplace force that they generate is low at this level. Indeed, the amplitude of the magnetic field that a permanent magnet 28, 30 produces decreases as one moves away from the magnet, that is to say here as one approaches the main axis A.

[0053] In particular, the second permanent magnets 30 are arranged at a significant transverse distance from the main axis A. Thus, the amplitude of the magnetic field that they produce at the contact pads 24, 26 is relatively low. Between the first permanent magnets 28 and the second permanent magnets 30, and outside the area of ​​the movable contact 20, they together produce a greater magnetic field since they interact with each other.

[0054] To improve the magnetic field near the main axis A and also to prevent an electric arc from catching on the guide rod 22, the breaking chamber 10 further comprises a screen 34 made of an electrically insulating material which is arranged between the fixed contacts 18.

[0055] The screen 34 consists of a generally parallelepiped element which also surrounds the guide rod 22. The screen 34 comprises for this purpose a housing 38 coaxial with the main axis A, in which the guide rod 22 is received.

[0056] The longitudinal dimension of the screen 34 is preferably greater than the longitudinal dimension of the fixed contacts 18 and the screen 34 projects longitudinally at its two longitudinal ends relative to the fixed contacts 18.

[0057] Also, according to a preferred embodiment, the vertical dimension of the screen 34 is greater than a vertical clearance between the movable contact 20 and each fixed contact 18, when the movable contact 20 is in the open position. In addition, the vertical dimension of the screen 34 is defined so that the screen 34 projects vertically both downwards and upwards relative to this vertical clearance.

[0058] Thus, the screen 34 prevents any electric arc forming between a fixed contact 18 and the movable contact 20 from moving towards the guide rod 22 and even less towards the other fixed contact 18.

[0059] The screen further carries two third permanent magnets 36 which are arranged transversely on either side of the guide rod 22. These third permanent magnets 36, which are therefore integral with the screen, are further located transversely between the two fixed contacts 18.

[0060] That is, every third permanent magnet 36 is located transversely between the guide rod 22 and a fixed contact 18.

[0061] The third permanent magnets 36 generate additional magnetic fields whose intensity near the main axis A is sufficiently high so that the Laplace force produced can cause an electric arc towards the cut-off zone 32.

[0062] According to a first embodiment, the screen 34 is fixed in the body 12.

[0063] According to a second embodiment, the screen 34 is mounted to move in translation in the body 12. Preferably, according to this second embodiment, the screen 34 is integral with the movable contact 20 in vertical translation relative to the fixed contacts 18.

[0064] Nomenclature:

[0065] 10: cutting chamber

[0066] 12: body

[0067] 14: volume

[0068] 16: support plate

[0069] 18: fixed contacts

[0070] 20: mobile contact

[0071] 22: guide rod

[0072] 24: contact pads of fixed contacts

[0073] 26: contact pads of the moving contact

[0074] 28: first permanent magnets

[0075] 30: second permanent magnets

[0076] 32: cut-off zone

[0077] 34: screen

[0078] 36: third permanent magnets

[0079] 38: housing

Claims

Claims 1. High-voltage breaking chamber (10) having a vertical main axis A and comprising two fixed contacts (18) offset from each other in a transverse direction perpendicular to the main axis A and a movable contact (20), in which the movable contact (20) is mounted movable in translation relative to the fixed contacts (18) in the direction of the main axis A between a closed position in which the movable contact (20) is simultaneously in electrical contact with the two fixed contacts (18) and an open position in which the movable contact (20) is located axially at a distance from the two fixed contacts (18), the breaking chamber (10) further comprising first permanent magnets (28) and second permanent magnets (30) which are distributed longitudinally or transversely on either side of the fixed contacts (18) and the movable contact (20),the breaking chamber (10) further comprising a screen (34) made of an electrically insulating material, which is arranged between the fixed contacts (18), characterized in that the screen (34) is integral with the movable contact (20) in translation relative to the fixed contacts (18)., 2. Cutting chamber (10) according to any one of the preceding claims, characterized in that the longitudinal dimension of the screen (34) is greater than the longitudinal dimension of the fixed contacts (18) and the screen (34) projects longitudinally at its two longitudinal ends relative to the fixed contacts (18).

3. Cutting chamber (10) according to any one of the preceding claims, characterized in that the vertical dimension of the screen (34) is greater than a vertical clearance between the movable contact (20) and each fixed contact (18) when the movable contact (20) is in the open position and the screen (34) projects vertically downwards and upwards relative to this vertical clearance.

4. Cutting chamber (10) according to any one of the preceding claims, characterized in that the screen (34) carries two third permanent magnets (36) which are arranged transversely between the fixed contacts (18).

5. Cutting chamber (10) according to any one of the preceding claims, which comprises a guide rod (22) providing guidance of the movable contact (20) in translation, characterized in that the screen (34) is guided in translation by the guide rod (22).

6. Cutting chamber (10) according to the preceding claim, in combination with claim 5, characterized in that each third permanent magnet (36) is arranged transversely between the guide rod (22) and a fixed contact (18).

7. Cutting chamber (10) according to any one of the preceding claims, characterized in that the first permanent magnets (28) are arranged longitudinally on either side of the fixed contacts (18).

8. Cutting chamber (10) according to any one of the preceding claims, characterized in that the second permanent magnets (30) are arranged transversely on either side of the fixed contacts (18).

9. Electrical installation comprising one or more breaking chambers according to any one of the preceding claims.

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