Electric current cut-off device

Abstract

An electrical current cut-off device (50) is proposed, comprising: - a first line portion comprising a first electrical conductor (3) and a fixed contact (5) secured to the first conductor (3), - a second line portion comprising a second electrical conductor (4) and a rotating movable contact (6) configured to be moved between: - an open position preventing the passage of current, and - a closed position allowing the passage of current, the movable contact (6) extending, in the closed position, in a direction transverse to an extension direction (D3) of the first electrical conductor (3), the fixed contact (5) comprising a first portion (11) configured to be in contact with the movable contact (6) and a second portion (12) fixed to the first electrical conductor (3),in which the first portion (11) and the second portion (12) are offset according to the direction of extension (D3) of the first electrical conductor (3).,

Description

Domaine technique

[0001] The present invention relates to the field of cut-off devices for medium voltage electrical appliances, i.e. from 1 to 52 kV. These cut-off devices make it possible to cut off or establish the flow of current in a medium voltage electrical network. Technique antérieure

[0002] Switches used in medium-voltage electrical networks may comprise at least one fixed contact and one movable contact rotating between at least two positions. One of the positions corresponds to a position separating the fixed contact and the movable contact, called the open position, in which the current is interrupted. One of the positions corresponds to a position in which the fixed contact and the movable contact are in mechanical and electrical contact, called the closed position, allowing current to flow in the circuit.

[0003] The movable contact can be moved alternately from one position to another by means of a control mechanism. Such a switch is placed on each phase of the electrical network. Some switches have three positions, the third position corresponding to grounding a portion of the circuit.

[0004] When establishing the flow of electric current, i.e. when the interrupter moves from the open position of the circuit to the closed position, the current intensity can be particularly high when a short circuit is present in the circuit to be connected. A short circuit can also occur when the switch is already in the closed position. The intensity of the short-circuit current can exceed 50,000 amperes for a period of a few tens of milliseconds, until a protective device located upstream of the switch opens the electric circuit. The electrodynamic forces generated by such a short-circuit current generally tend to cause the movable contact to reopen. Such a reopening should be avoided, due to the risk of damage due to the electric arcs created.

[0005] There is a need for switches in which the risk of reopening on short circuit is eliminated or at least reduced. Résumé

[0006] To this end, the invention proposes an electric current cut-off device, comprising: a first portion of electrical line comprising a first electrical conductor and a fixed contact secured to the first electrical conductor, a second portion of electrical line comprising a second electrical conductor and a contact which can rotate relative to the second electrical conductor, the movable contact being configured to be moved between: a first position called the open position in which the movable contact is spaced from the fixed contact so as to prevent the passage of electric current between the first portion of electric line and the second portion of electric line, and a second position called the closed position in which the movable contact is in contact with the fixed contact so as to allow the passage of electric current between the first portion of electric line and the second portion of electric line, in which the movable contact extends, in the second position, in a direction transverse to a direction of extension of the first electrical conductor, in which the fixed contact comprises a first portion configured to be in contact with the movable contact and a second portion fixed to the first electrical conductor,and wherein the first portion and the second portion are offset from each other in the direction of extension of the first electrical conductor.

[0007] The offset between the first portion, through which the electric current enters the fixed contact, and the second portion, through which the electric current leaves the fixed contact, makes it possible to soften the change in direction of the electric current. The electrodynamic forces tending to open the movable contact, particularly when a circuit current flows in the electric line, are thus reduced. The capacity of the breaking device is increased.

[0008] The characteristics listed in the following paragraphs can be implemented independently of each other or in any technically possible combination: At least part of the first portion is separated from the first electrical conductor by a portion devoid of material.

[0009] At least a portion of the first portion is separated from the first electrical conductor by a gas void. The gas is the gas surrounding the switch. The gas may, for example, be air, or another gas having good electrical insulating properties.

[0010] The first portion and the second portion partially overlap along the direction of extension of the first electrical conductor.

[0011] According to one embodiment of the electrical current cut-off device, the first portion of the fixed contact is opposite an end portion of the first electrical conductor.

[0012] According to one aspect of the electrical current cut-off device, the fixed contact comprises a bearing face configured to be in contact with the first electrical conductor, and the first portion is connected to the bearing face by a portion of material having a concave shape.

[0013] In other words, certain straight line segments joining the first portion to the support face are not contained within the volume delimited by the outer surface of the fixed contact.

[0014] The first electrical conductor comprises, for example, a rod for conducting the electric current. Similarly, the second electrical conductor comprises, for example, a rod for conducting the electric current.

[0015] The first electrical conductor is secured to a frame. The second electrical conductor is secured to the frame.

[0016] The first electrical conductor is, for example, formed by a rod, for example a copper rod. Similarly, the second electrical conductor can be formed by a copper rod.

[0017] Each rod can have a rectangular cross-section.

[0018] The fixed contact is rigidly connected to the frame.

[0019] The moving contact is movable in rotation relative to the frame.

[0020] According to an exemplary embodiment, the movable contact has the shape of a rod, for example a straight rod.

[0021] According to one embodiment, the movable contact is articulated at a first end. The movable contact comprises at its second end opposite the first end a contact zone. The contact zone is configured to establish electrical contact with the fixed contact of the first electrical conductor when the movable contact is in the second position called the closed position.

[0022] In this embodiment, the movable contact establishes permanent electrical contact with the second electrical contact at the joint.

[0023] According to another embodiment, the movable contact is articulated at a middle portion located between the first end and the second end. The movable contact comprises at a first end a first contact zone configured to establish electrical contact with the fixed contact of the first electrical conductor when the movable contact is in the second position, called the closed position. The movable contact comprises at its second end a second contact zone configured to establish electrical contact with the second electrical conductor when the movable contact is in the second position, called the closed position.

[0024] In other words, in this embodiment the second electrical conductor itself comprises a fixed contact which can be selectively moved away from the movable contact or engaged with the movable contact. A rotation of the movable contact makes it possible to establish mechanical and electrical contact between the movable contact and each of the first and second electrical conductors. In the first position, called the open position, the movable contact is moved away from the fixed contact of the first electrical conductor and from the fixed contact of the second electrical conductor.

[0025] According to one embodiment of the electrical current cut-off device, the movable contact comprises two electrically conductive and mechanically linked knives, the two knives being parallel to each other and at a distance from each other, and the fixed contact is in contact with each of the knives when the movable contact is in the second position.

[0026] The first portion is arranged between the knives when the moving contact is in the second position.

[0027] According to an embodiment of the electrical current cut-off device, in which the fixed contact comprises a bearing face configured to be in contact with the first electrical conductor, a distance between one end of the first portion of the fixed contact, oriented opposite the bearing face in an axial direction, and one end of the bearing face located opposite the first portion, the distance being measured parallel to the main direction of extension of the bearing face, is between 50% and 100% of a length of the first portion, the length being measured parallel to a direction of extension of the first portion.

[0028] According to an embodiment of the electrical current cut-off device, in which the fixed contact comprises a bearing face configured to be in contact with the first electrical conductor, a distance between one end of the first portion of the fixed contact, opposite the bearing face in an axial direction, and one end of the bearing face located opposite the first portion, the distance being measured parallel to the main direction of extension of the bearing face, is between 100% and 300% of a distance between the first portion and the bearing face, the distance being measured parallel to a direction perpendicular to the bearing face.

[0029] These offset values make it possible to reduce the electrodynamic forces on the moving contact while maintaining the mechanical resistance of the fixed contact at a sufficient value.

[0030] According to one embodiment of the electrical current cut-off device, the fixed contact comprises: a first part of generally parallelepiped shape, comprising a bearing face configured to be in contact with the first electrical conductor, a second part of generally cylindrical shape extending the first part in a direction perpendicular to the bearing face, the second part being offset relative to the bearing face in a main direction of extension of the bearing face, and the first portion of the fixed contact is formed by a portion of a peripheral surface of the second part.

[0031] The main direction of extension of the support face and the axis of the second part are parallel.

[0032] The main direction of extension of the bearing face and the axis of the second part define a plane perpendicular to the axis of rotation of the moving contact.

[0033] According to one embodiment of the electric current cut-off device, the second part of the fixed contact is extended, in an axial direction, by a third part inclined towards the first part of the fixed contact.

[0034] The inclined part of the fixed contact helps to reduce the electrodynamic forces on the moving contact, and thus further reduce the tendency of the contacts to separate, particularly during a short circuit.

[0035] According to an exemplary embodiment of the electric current cut-off device, in a section along a plane passing through the main direction of extension of the support face and perpendicular to the support face, an outer periphery of the third part forms an angle of between 30° and 50° with a direction of extension of the second part.

[0036] According to an example of implementation of the electric current cut-off device, one end of the second part of the fixed contact, opposite the first part in an axial direction, has a substantially hemispherical shape.

[0037] According to an embodiment of the electrical current cut-off device, a distance between one end of the second part of the fixed contact, opposite the first part in an axial direction, and one end of the first part of the fixed contact, located opposite the second part, the distance being measured parallel to the main direction of extension of the bearing face, is between 50% and 100% of a length of the second part of the fixed contact, the length being measured parallel to the axis of extension of the second part.

[0038] According to an embodiment of the electrical current cut-off device, a distance between one end of the second part of the fixed contact, opposite the first part in an axial direction, and one end of the first part of the fixed contact, located opposite the second part, the distance being measured parallel to the main direction of extension of the bearing face, is between 50% and 100% of a length of the bearing face of the first part of the fixed contact, the length being measured parallel to the main direction of extension of the bearing face.

[0039] According to one embodiment, a length of the third part is between 5% and 100% of a length of the bearing face of the first part of the fixed contact, the length of the third part and the length being measured parallel to the main direction of extension of the bearing face.

[0040] According to one embodiment of the electrical current cut-off device, a distance between a proximal edge of the second part of the fixed contact, facing the bearing face, and the bearing face, the distance being measured in a direction perpendicular to the bearing face, is between 20% and 100% of a length of the second part of the fixed contact, the length being measured parallel to the extension axis of the second part.

[0041] The fixed contact, for example, forms a single-piece assembly.

[0042] The fixed contact is for example made of copper.

[0043] The first part comprises two threaded bores opening into the bearing face, each threaded bore being configured to respectively receive a screw for fixing to the first electrical conductor.

[0044] According to one embodiment, the electrical current cut-off device comprises a magnetically conductive insert disposed partly between the first electrical conductor and the fixed contact, the insert extending opposite the fixed contact.

[0045] The magnetic insert allows, when the current passes through the fixed contact, to create a magnetic field generating on the moving contact a force tending to oppose the opening of the moving contact.

[0046] According to an exemplary embodiment, the magnetically conductive insert comprises a first portion extending parallel to the bearing surface extended by a second portion extending perpendicular to the bearing surface towards the first portion of the fixed contact.

[0047] The first portion of the magnetically conductive insert has the general shape of a plate.

[0048] The second portion of the magnetically conductive insert has the general shape of a plate.

[0049] The first portion of the fixed contact is opposite the first portion of the magnetically conductive insert in a direction perpendicular to the support surface.

[0050] The first portion of the fixed contact is opposite the second portion of the magnetically conductive insert in a direction parallel to the main direction of extension of the support surface.

[0051] A distance between the end of the second part of the fixed contact, opposite the first part in an axial direction, and the second portion of the magnetically conductive insert is between 1% and 10% of the length of the first portion.

[0052] The second portion of the magnetically conductive insert may comprise a thinned portion arranged opposite the first portion of the fixed contact.

[0053] In the closed position, the movable contact is opposite the first portion of the magnetically conductive insert in a longitudinal direction of the movable contact.

[0054] In the closed position, the movable contact is opposite the second portion of the magnetically conductive insert in a direction transverse to the longitudinal direction of the movable contact.

[0055] A median plane of the fixed contact coincides with a median plane of the magnetically conductive insert.

[0056] The magnetically conductive insert is, for example, made of ferromagnetic steel.

[0057] The magnetically conductive insert is, for example, formed by cutting and bending a metal strip.

[0058] According to one embodiment of the electric current cut-off device, the first portion of the magnetically conductive insert comprises a recess for passage of a part of the second portion of the fixed contact.

[0059] The invention also relates to a medium voltage electrical apparatus, configured to selectively establish or cut off the current in a medium voltage electrical network comprising three phases, comprising an electrical current cut-off device as described previously arranged respectively on each of the phases of the electrical network.

[0060] The electrical device can be a line disconnector, or a circuit breaker. Brève description des dessins

[0061] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: There figure 1 is a schematic representation of an electrical device comprising a cut-off device, in the current cut-off position, The figure 2 is a schematic representation of the electrical apparatus of the figure 1 , in the current flow position, The figure 3 is a schematic representation, from the side, of a cutting device according to the invention, The figure 4 is a schematic representation, from the side, of a cutting device according to an alternative embodiment of the invention, The figure 5 is a perspective view of a cut-off device according to a first embodiment, shown in the current cut-off position, The figure 6 is a perspective view of a variant of the cut-off device of the figure 5 , represented in the current flow position, The figure 7 is a perspective view of the fixed contact of the cut-off device of the figure 5 , There figure 8 is another perspective view of the fixed contact of the cut-off device of the figure 5 , There figure 9 is yet another perspective view of the fixed contact of the cut-off device of the figure 5 , There figure 10 is a sectional view of the fixed contact of the cut-off device of the figure 5 , There figure 11 is a partial perspective view of a cut-off device according to a second embodiment, shown in the current cut-off position, The figure 12 is a partial side view of the cut-off device of the figure 11 , There figure 13 is a perspective view of the cut-off device of the figure 12 , shown in the current flow position. Description des modes de réalisation

[0062] To facilitate reading the figures, the different elements are not necessarily represented to scale. In these figures, identical elements bear the same references. Certain elements or parameters may be indexed, i.e. designated for example by first element or second element, or first parameter and second parameter, etc. This indexing is intended to differentiate similar, but not identical, elements or parameters. This indexing does not imply a priority of one element or parameter over another and the names may be interchanged. When it is specified that a device includes a given element, this does not exclude the presence of other elements in this device. Similarly, when it is specified that a device includes a given element, it is understood that the device includes at least this element.In the different figures, the X, Y, Z axes designate the three directions of space in order to identify the viewing angle of each figure.

[0063] It has been represented on the figure 1 a medium voltage electrical device 100, configured to selectively establish or cut off the current in a medium voltage electrical network. The electrical network comprises three phases L1, L2 L3, and comprises an electrical current cut-off device 50, 50', 50" arranged respectively on each of the phases L1, L2, L3 of the electrical network.

[0064] The electrical device 100 can be a line disconnector, or a circuit breaker.

[0065] There figure 1 schematically represents the electrical device 100 when each of the electrical current cut-off devices 50, 50', 50" is in the current cut-off position, preventing the flow of electric current. The figure 2 schematically represents the electrical apparatus 100 when each of the electrical current cut-off devices 50, 50', 50" is in the current establishment position, in which an electrical current can flow in the network. A control device 80 makes it possible to control each of the electrical current cut-off devices 50, 50', 50".

[0066] An electric current cut-off device 50 will now be described in detail.

[0067] The proposed 50 electric power cut-off device comprises: a first portion of electrical line 1 comprising a first electrical conductor 3 and a fixed contact 5 secured to the first electrical conductor 3, a second portion of electrical line 2 comprising a second electrical conductor 4 and a movable contact 6 rotating relative to the second electrical conductor 4. Movable contact 6 is configured to be moved between: a first position P1 called the open position in which the movable contact 6 is spaced from the fixed contact 5 so as to prevent the passage of electric current between the first portion of electric line 1 and the second portion of electric line 2, and a second position P2 called the closed position in which the movable contact 6 is in contact with the fixed contact 5 so as to allow the passage of electric current between the first portion of electric line 1 and the second portion of electric line 2. The movable contact 6 extends, in the second position P2, in a direction D6 transverse to an extension direction D3 of the first electrical conductor 3. The fixed contact 5 comprises a first portion 11 configured to be in contact with the movable contact 6 and a second portion 12 fixed to the first electrical conductor 3. The first portion 11 and the second portion 12 are offset relative to each other along the direction of extension D3 of the first electrical conductor 3.

[0068] The offset, along the direction of extension D3 of the first electrical conductor 3, between the first portion 11 and the second portion 12 makes it possible to soften the change in direction of the electric current. The electrodynamic forces tending to open the movable contact 6, in particular when a circuit current flows in the electrical line, are thus reduced. The capacity of the breaking device 50 is increased, that is to say that a higher short-circuit intensity can be accepted by the breaking device 50.

[0069] There figure 3 schematically represents the flow of current between the electrical conductor 3, the fixed contact 5 and the movable contact 6. The dotted lines designated by the signs f1, f2 schematically represent the direction of the electric current.

[0070] The electric current being alternating, the first portion 11 can be an inlet of electric current into the fixed contact 5, and the second portion 12 is then simultaneously an outlet of electric current from the fixed contact 5. During another half-period of the alternating current, the current flow is reversed. The first portion 11 is then an outlet of electric current into the fixed contact 5, and the second portion 12 is simultaneously an inlet of electric current into the fixed contact 5.

[0071] The first electrical conductor 3 comprises, in the illustrated example, a rod for conducting the electric current. Similarly, the second electrical conductor 4 here comprises a rod for conducting the electric current.

[0072] The first electrical conductor 3 is secured to a frame 10. The second electrical conductor 4 is secured to the frame 10. The rigid frame 10 forms a structure for fixing the various components of the electrical device 100.

[0073] The first electrical conductor 3 is for example formed by a rod, for example a copper rod. Similarly, the second electrical conductor 4 can also be formed by a copper rod.

[0074] Each rod may have a rectangular cross-section. The first electrical conductor 3 is thus rigid. The second electrical conductor 4 is also rigid.

[0075] The fixed contact 5 is rigidly connected to the frame 10. The movable contact 6 is movable in rotation relative to the frame. According to an exemplary embodiment, the movable contact 6 has the shape of a rod, for example a straight rod.

[0076] It is understood that, in the second position P2, the movable contact 6 extends in a direction D6 transverse to an extension direction D3 of the first electrical conductor 3, the angle B between the extension direction D6 of the movable contact 6 and the extension direction D3 of the first electrical conductor 3 is between 60° and 90°.

[0077] According to one embodiment, the movable contact 6 is articulated at a first end 6-1. The movable contact 6 comprises at its second end 6-2 opposite the first end 6-1 a contact zone 21. The contact zone 21 is configured to establish electrical contact with the fixed contact 5 of the first electrical conductor 3 when the movable contact 6 is in the second position P2 called the closed position. In this embodiment, the movable contact 6 establishes permanent electrical contact with the second electrical conductor 4 at the articulation. This type of movable contact is shown in the figures 5 , 6 , 7 as well as on the figure 12 .

[0078] According to another embodiment, illustrated schematically in the figure 4 , the movable contact 6 is articulated at a middle part 6-3 located between the first end 6-1 and the second end 6-2. The sign R' indicates the axis of rotation. The movable contact 6 comprises at a first end 6-1 a first contact zone 21A configured to establish electrical contact with the fixed contact 5 of the first electrical conductor 3 when the movable contact 6 is in the second position P2 called the closed position. The movable contact 6 comprises at its second end 6-2 a second contact zone 21B configured to establish electrical contact with the second electrical conductor 4 when the movable contact 6 is in the second position P2 called the closed position.

[0079] In other words, in this embodiment the second electrical conductor 4 itself comprises a fixed contact 5-2 which can be selectively moved away from the movable contact 6 or engaged with the movable contact 6. A rotation of the movable contact 6 makes it possible to establish mechanical and electrical contact between the movable contact 6 and each of the first and second electrical conductors 3, 4. In the first position P1 called the open position, the movable contact 6 is moved away from both the fixed contact 5 of the first electrical conductor 3 and the fixed contact 5' of the second electrical conductor 4.

[0080] The particular shape proposed for the fixed contact 5 can be applied to an electric current cut-off device in which the movable contact is hinged at one end, as to an electric current cut-off device in which the movable contact is hinged in its middle.

[0081] At least part of the first portion 11 is separated from the first electrical conductor 3 by a portion V devoid of material.

[0082] In other words, at least a part of the first portion 11 is separated from the first electrical conductor 3 by a gas vacuum. The gas is the gas surrounding the electrical current cut-off device 50, that is to say the gas contained inside the frame 10 of the electrical apparatus 100. The gas can for example be air, or another gas having good electrical insulation properties, such as sulfur hexafluoride. (chemical formula SF 6 )

[0083] The fixed contact 5 comprises a bearing face 7 configured to be in contact with the first electrical conductor 3, and the first portion 11 is linked to the bearing face 7 by a portion of material having a concave shape.

[0084] Certain straight line segments joining the first portion 11 to the bearing face 7 are thus not contained inside the volume delimited by the outer surface of the fixed contact 5. In other words, these straight line segments connecting the first portion 11 to the bearing face 7 come out of the material forming the fixed contact 5. On the figure 7 , segments c1, c2, c3 illustrate the concave-shaped portion of the fixed contact 5.

[0085] According to the illustrated example, the first portion 11 and the second portion 12 partially overlap along the direction of extension D3 of the first electrical conductor.

[0086] The direction of extension D3 of the first electrical conductor 3 is the direction in the vicinity of the fixed contact 5. That is to say that the direction of extension D3 of the first electrical conductor 3 is the direction in the immediate vicinity of the junction between the fixed contact 5 and the first electrical conductor 3. The direction of extension D3 of the first electrical conductor 3 is thus coincident with the main direction of extension D7 of the bearing face 7. The main direction of extension is understood to mean the axis of the largest dimension of the bearing face 7. It is thus the direction corresponding to the length of the bearing face 7. This main direction of extension is particularly visible on the figure 9 . The direction of extension D3 of the first electrical conductor 3 coincides with the main direction of extension D7 of the bearing face 7 in the vicinity of the fixed contact 5. In this figure, the sign T7 represents the direction transverse to the direction D7. This transverse direction corresponds to the width of the bearing face 7.

[0087] The shape of the first electrical conductor 3 may change along its length, in other words the first electrical conductor 3 is not necessarily rectilinear over its entire length. In the example shown, the first electrical conductor 3 comprises a U-shaped portion. The first electrical conductor 3 comprises a first rectilinear portion 3-1, extended by a curved portion 3-2, itself extended by a second rectilinear portion 3-3. The second rectilinear portion 3-3 and the first rectilinear portion 3-1 extend in parallel planes and are opposite each other. The second rectilinear portion 3-3 is extended by a third portion 3-4 forming an angle with the second rectilinear portion 3-3. The third portion 3-4 may be connected to another electrical conductor, not shown, forming part of the electrical line of the medium-voltage electrical apparatus 100.

[0088] According to the embodiment illustrated in the figure 5 , the first portion 11 of the fixed contact 5 is opposite an end portion 3A of the first electrical conductor 3.

[0089] According to one embodiment of the electrical current cut-off device 50, the movable contact 6 comprises two electrically conductive and mechanically linked knives 8, 9, the two knives 8, 9 being parallel to each other and at a distance from each other, and the fixed contact 5 is in contact with each of the knives 8, 9 when the movable contact 6 is in the second position P2.

[0090] The first portion 11 is arranged between the knives 8, 9 when the movable contact 6 is in the second position P2.

[0091] On the figure 5 , the movable contact 6 is in the opening position P1. The first knife 8 comprises a contact zone 21-1 and the second knife 9 comprises a contact zone 21-2. The contact zone 21-1 of the first knife 8 and the contact zone 21-2 of the second knife 9 are opposite each other.

[0092] The two knives 8, 9 are linked in rotation and can pivot simultaneously around the axis of rotation R. Two springs 22 exert on the first knife 8 a force tending to bring the first knife 8 closer to the second knife 9 in a direction parallel to the axis of rotation R. Two spacers 23 form a stop so as to keep the knives at a distance from each other when the movable contact 6 is in the open position P1, as in the figure 5 .

[0093] On the figure 6 , the movable contact 6 is in the closed position P2. A part of the fixed contact 5 is arranged between the two knives 8, 9. The contact zone 21-1 of the first knife 8 is in contact with a face of the first portion 11 of the fixed contact 5 and the contact zone 21-2 of the second knife 9 is in contact with an opposite face of the first portion 11 of the fixed contact 5. The springs 22 ensure sufficient contact pressure between the knives 8, 9 and the fixed contact 5.

[0094] The proposed fixed contact 5 may include special dimensions.

[0095] According to the illustrated example, in which the fixed contact 5 comprises a bearing face 7 configured to be in contact with the first electrical conductor 3, a distance da1 between one end of the first portion 11 of the fixed contact 5, oriented opposite the bearing face 7 in an axial direction, and one end 7A of the bearing face 7 located opposite the first portion 11, the distance da1 being measured parallel to the main direction of extension D7 of the bearing face 7, is between 50% and 100% of a length L11 of the first portion 11, the length L11 being measured parallel to a direction of extension D11 of the first portion 11.

[0096] According to the illustrated example, in which the fixed contact 5 comprises a bearing face 7 configured to be in contact with the first electrical conductor 3, a distance da1 between one end of the first portion 11 of the fixed contact 5, opposite the bearing face 7 in an axial direction, and one end of the bearing face 7 located opposite the first portion 11, the distance da1 being measured parallel to the main direction of extension D7 of the bearing face 7, is between 100% and 300% of a distance dt1 between the first portion 11 and the bearing face 7, the distance dt1 being measured parallel to a direction perpendicular to the bearing face 7.

[0097] These different dimensions are particularly illustrated on the figures 8 And 9 These offset values make it possible to reduce the electrodynamic forces on the moving contact 6 while maintaining the mechanical resistance of the fixed contact 5 at a sufficient value.

[0098] According to one embodiment of the electrical current cut-off device 50, the fixed contact 5 comprises: a first part 5A of generally parallelepiped shape, comprising a bearing face 7 configured to be in contact with the first electrical conductor 3, a second part 5B of generally cylindrical shape extending the first part 5A in a direction perpendicular to the bearing face 7, the second part 5B being offset relative to the bearing face 7 along a main direction of extension D7 of the bearing face 7, and the first portion 11 of the fixed contact 5 is formed by a portion of a peripheral surface of the second part 5B.

[0099] The main direction of extension D7 of the bearing face 7 and the axis D5B of the second part 5B are parallel. The main direction of extension D7 of the bearing face 7 and the axis D5B of the second part 5B define a plane perpendicular to the axis of rotation R of the movable contact 6.

[0100] By general parallelepiped shape is meant that the first part 5A comprises two opposite, flat and substantially parallel faces 5A-a, 5A-b. These two flat faces 5A-a, 5A-b are respectively connected to each other, at each of their ends, by two portions 5A-c, 5A-d. The two portions 5A-c, 5A-d each comprise two rounded portions connected by a flat area.

[0101] According to the illustrated embodiment, the second part 5B of the fixed contact 5 is extended, in an axial direction, by a third part 5C inclined towards the first part 5A of the fixed contact 5.

[0102] The inclined portion 5C of the fixed contact contributes to reducing the electrodynamic forces on the moving contact 6, and thus to further reducing the tendency of the contacts 5, 6 to separate, in particular during a short circuit.

[0103] In a section along a plane passing through the main direction of extension D7 of the bearing face 7 and perpendicular to the bearing face 7, an outer periphery E5C of the third part 5C forms an angle A of between 30° and 50° with a direction of extension D5B of the second part 5B. This angle A is illustrated in the figures 3 , 8 And 10 .

[0104] According to the illustrated example, one end 5B-1 of the second part 5B of the fixed contact 5, opposite the first part 5A in an axial direction, has a substantially hemispherical shape.

[0105] In other words, the second part 5B, of generally cylindrical shape, ends on one side with a rounded portion having a shape close to that of a half-sphere. On the other side in an axial direction, the second part 5B connects to the third part 5C. In a radial direction, the second part 5B connects to the first part 5A.

[0106] The first part 5A of generally parallelepiped shape, the second part 5B of generally cylindrical shape and the third inclined part 5C may comprise particular dimensions.

[0107] A distance da2 between an end 5B-1 of the second part 5B of the fixed contact 5, opposite the first part 5A in an axial direction, and an end 5A-1 of the first part 5A of the fixed contact 5, located opposite the second part 5B, the distance da2 being measured parallel to the main direction of extension D7 of the bearing face 7, is between 50% and 100% of a length L5B of the second part 5B of the fixed contact 5, the length L5B being measured parallel to the axis of extension D5B of the second part 5B.

[0108] In addition, a distance da2 between an end 5B-1 of the second part 5B of the fixed contact 5, opposite the first part 5A in an axial direction, and an end 5A-1 of the first part 5A of the fixed contact 5, located opposite the second part 5B, the distance da2 being measured parallel to the main direction of extension D7 of the bearing face 7, is between 50% and 100% of a length L7 of the bearing face 7 of the first part 11 of the fixed contact 5, the length L7 being measured parallel to the main direction of extension D7 of the bearing face 7.

[0109] A length L5C of the third part 5C is between 5% and 100% of a length L7 of the bearing face 7 of the first part 11 of the fixed contact 5, the length L5C of the third part 5C and the length L7 being measured parallel to the main direction of extension D7 of the bearing face 7.

[0110] A distance dt2 between a proximal edge 5B-2 of the second part 5B of the fixed contact 5, facing the bearing face 7, and the bearing face 7, the distance being measured in a direction perpendicular to the bearing face 7, is between 20% and 100% of a length L5B of the second part 5B of the fixed contact 5, the length L5B being measured parallel to the extension axis of the second part 5B.

[0111] These dimensions are illustrated on the figures 8 , 9 And 10 . As stated previously, these dimensions make it possible to reduce the electrodynamic forces on the moving contact 6 while maintaining the mechanical resistance of the fixed contact 5 at a sufficient value.

[0112] The fixed contact 5 forms, for example, a single-piece assembly. The fixed contact 5 is, for example, made of copper. According to an alternative embodiment not illustrated, the fixed contact 5 may be formed by an assembly of several parts.

[0113] The first part 5A comprises two threaded bores 14A, 14B opening into the bearing face 7, each threaded bore 14A, 15B being configured to respectively receive a fixing screw 25 to the first electrical conductor 3.

[0114] The fixed contact 5 is for example solid, that is to say that the fixed contact 5 does not include an internal cavity, with the exception of the threaded bores allowing its attachment to the first electrical conductor 3.

[0115] THE figures 11, 12 , 13 illustrate a second embodiment in which an additional element is added.

[0116] According to this second embodiment, the electrical current cut-off device 50 comprises a magnetically conductive insert 16 arranged partly between the first electrical conductor 3 and the fixed contact 5, the insert 16 extending opposite the fixed contact 5.

[0117] The magnetic insert 16 makes it possible to create, when the electric current passes through the fixed contact 5 and the movable contact 6, a magnetic field generating on the movable contact 6 a force tending to oppose the opening of the movable contact 6.

[0118] THE figures 11 et 12 show the magnetic insert 16 when the movable contact 6 is in the open position. This is therefore not visible in these two figures. figure 13 shows the magnetic insert 16 when the movable contact 6 is in the closed position P2.

[0119] As illustrated in particular on the figure 11 , the magnetically conductive insert 16 comprises a first portion 17 extending parallel to the bearing surface 7 extended by a second portion 18 extending perpendicular to the bearing surface 7 towards the first portion 11 of the fixed contact 5.

[0120] The first portion 17 of the magnetically conductive insert 16 has the general shape of a plate. The second portion 18 of the magnetically conductive insert 16 has the general shape of a plate.

[0121] The first portion 11 of the fixed contact 5 is opposite the first portion 17 of the magnetically conductive insert 16 in a direction perpendicular to the bearing surface 7.

[0122] The first portion 11 of the fixed contact 5 is opposite the second portion 18 of the magnetically conductive insert 16 in a direction parallel to the main direction of extension D7 of the bearing surface 7.

[0123] As indicated on the figure 12 , a distance da3 between the end 5B-1 of the second part 5B of the fixed contact 5, opposite the first part 5A in an axial direction, and the second portion 18 of the magnetically conductive insert 16 is between 1% and 10% of the length L11 of the first portion 11.

[0124] The second portion 18 of the magnetically conductive insert 16 may comprise a thinned portion 20 arranged opposite the first portion 11 of the fixed contact 5. The thinned portion 20 is shown in the figures 11 And 13 .

[0125] In the closed position P2, the movable contact 6 is opposite the first portion 17 of the magnetically conductive insert 16 in a longitudinal direction D6 of the movable contact 6.

[0126] In the closed position P2, the movable contact 6 is opposite the second portion 18 of the magnetically conductive insert 16 in a direction transverse to the longitudinal direction of the movable contact 6.

[0127] A median plane of the fixed contact 5 coincides with a median plane of the magnetically conductive insert 16.

[0128] The magnetically conductive insert 16 is, for example, made of ferromagnetic steel. The magnetically conductive insert 16 is, for example, formed by cutting and bending a metal strip. The thickness e of the metal strip is, for example, between 1 millimeter and 10 millimeters.

[0129] According to the illustrated example, the first portion 17 of the magnetically conductive insert 16 comprises a recess 19 for the passage of a part of the second portion 12 of the fixed contact 5. The recess of the first portion 17 defines three consecutive facets of a rectangle. The three facets surround the second portion 12 of the fixed contact 5. A clearance is present between each facet and the second portion 12 of the fixed contact 5.

[0130] The electrical current cut-off devices 50, 50', 50" of the electrical appliance 100 may be identical. The cut-off devices 50', 50" respectively comprise a movable contact 6', 6" making it possible to selectively establish or interrupt the current between a first electrical conductor 3', 3" and a second electrical conductor 4', 4". The first electrical conductor 3', 3" comprises a fixed contact 5', 5".

Claims

1. Electric current cut-off device (50), comprising: - a first portion of electric line (1) comprising a first electrical conductor (3) and a fixed contact (5) secured to the first electrical conductor (3), - a second portion of electric line (2) comprising a second electrical conductor (4) and a movable contact (6) rotating relative to the second electrical conductor (4), the movable contact (6) being configured to be moved between: - a first position (P1) called the open position in which the movable contact (6) is spaced from the fixed contact (5) so as to prevent the passage of electric current between the first portion of electric line (1) and the second portion of electric line (2),and - a second position (P2) called the closed position in which the movable contact (6) is in contact with the fixed contact (5) so as to allow a passage of electric current between the first portion of electric line (1) and the second portion of electric line (2), in which the movable contact (6) extends, in the second position (P2), in a direction (D6) transverse to a direction of extension (D3) of the first electrical conductor (3), in which the fixed contact (5) comprises a first portion (11) configured to be in contact with the movable contact (6) and a second portion (12) fixed to the first electrical conductor (3), and in which the first portion (11) and the second portion (12) are offset relative to each other in the direction of extension (D3) of the first electrical conductor (3)., 2. Electrical current cut-off device (50) according to claim 1, in which the first portion (11) of the fixed contact (5) is opposite an end portion (3A) of the first electrical conductor (3).

3. Electrical current cut-off device (50) according to claim 1 or 2, wherein the fixed contact (5) comprises a bearing face (7) configured to be in contact with the first electrical conductor (3), and wherein the first portion (11) is linked to the bearing face (7) by a portion of material having a concave shape.

4. Electrical current cut-off device (50) according to one of the preceding claims, in which the movable contact (6) comprises two electrically conductive and mechanically linked knives (8, 9), the two knives (8, 9) being parallel to each other and at a distance from each other, in which the fixed contact (5) is in contact with each of the knives (8, 9) when the movable contact (6) is in the second position (P2).

5. Electrical current cut-off device (50) according to one of the preceding claims, wherein the fixed contact (5) comprises a bearing face (7) configured to be in contact with the first electrical conductor (3), and wherein a distance (da1) between one end of the first portion (11) of the fixed contact (5), oriented opposite the bearing face (7) in an axial direction, and one end (7A) of the bearing face (7) located opposite the first portion (11), the distance (da1) being measured parallel to the main direction of extension (D7) of the bearing face (7), is between 50% and 100% of a length (L11) of the first portion (11), the length (L11) being measured parallel to a direction of extension (D11) of the first portion (11).

6. Electrical current cut-off device (50) according to one of the preceding claims, wherein the fixed contact (5) comprises a bearing face (7) configured to be in contact with the first electrical conductor (3), and wherein a distance (da1) between one end of the first portion (11) of the fixed contact (5), opposite the bearing face (7) in an axial direction, and one end of the bearing face (7) located opposite the first portion (11), the distance (da1) being measured parallel to the main direction of extension (D7) of the bearing face (7), is between 100% and 300% of a distance (dt1) between the first portion (11) and the bearing face (7), the distance (dt1) being measured parallel to a direction perpendicular to the bearing face (7).

7. Electrical current cut-off device (50) according to one of the preceding claims, wherein the fixed contact (5) comprises: - a first part (5A) of generally parallelepipedal shape, comprising a bearing face (7) configured to be in contact with the first electrical conductor (3), - a second part (5B) of generally cylindrical shape extending the first part (5A) in a direction perpendicular to the bearing face (7), the second part (5B) being offset relative to the bearing face (7) in a main direction of extension (D7) of the bearing face (7), wherein the first portion (11) of the fixed contact (5) is formed by a portion of a peripheral surface of the second part (5B).

8. Electric current cut-off device (50) according to the preceding claim, in which the second part (5B) of the fixed contact (5) is extended, in an axial direction, by a third part (5C) inclined towards the first part (5A) of the fixed contact (5).

9. Electric current cut-off device (50) according to the preceding claim, in which, in a section along a plane passing through the main direction of extension (D7) of the bearing face (7) and perpendicular to the bearing face (7), an outer periphery (E5C) of the third part (5C) forms an angle (A) of between 30° and 50° with a direction of extension (D5B) of the second part (5B).

10. Electric current cut-off device (50) according to one of claims 7 to 9, in which one end (5B-1) of the second part (5B) of the fixed contact (5), opposite the first part (5A) in an axial direction, has a substantially hemispherical shape.

11. An electrical current cut-off device (50) according to one of claims 7 to 10, wherein a distance (da2) between an end (5B-1) of the second part (5B) of the fixed contact (5), opposite the first part (5A) in an axial direction, and an end (5A-1) of the first part (5A) of the fixed contact (5), located opposite the second part (5B), the distance (da2) being measured parallel to the main direction of extension (D7) of the bearing face (7), is between 50% and 100% of a length (L5B) of the second part (5B) of the fixed contact (5), the length (L5B) being measured parallel to the axis of extension of the second part (5B).

12. An electrical current cut-off device (50) according to one of claims 7 to 11, wherein a distance (da2) between an end (5B-1) of the second part (5B) of the fixed contact (5), opposite the first part (5A) in an axial direction, and an end (5A-1) of the first part (5A) of the fixed contact (5), located opposite the second part (5B), the distance (da2) being measured parallel to the main direction of extension (D7) of the bearing face (7), is between 50% and 100% of a length (L7) of the bearing face (7) of the first part (11) of the fixed contact (5), the length (L7) being measured parallel to the main direction of extension (D7) of the bearing face (7).

13. Electric current cut-off device (50) according to one of claims 7 to 12 in combination with claim 8, wherein a length (L5C) of the third part (5C) is between 5% and 100% of a length (L7) of the bearing face (7) of the first part (11) of the fixed contact (5), the length (L5C) of the third part (5C) and the length (L7) being measured parallel to the main direction of extension (D7) of the bearing face (7).

14. An electrical current cut-off device (50) according to one of claims 7 to 13, wherein a distance (dt2) between a proximal edge (5B-2) of the second part (5B) of the fixed contact (5), facing the bearing face (7), and the bearing face (7), the distance being measured in a direction perpendicular to the bearing face (7), is between 20% and 100% of a length (L5B) of the second part (5B) of the fixed contact (5), the length (L5B) being measured parallel to the axis of extension of the second part (5B).

15. Electrical current cut-off device (50) according to one of the preceding claims, comprising a magnetically conductive insert (16) arranged partly between the first electrical conductor (3) and the fixed contact (5), the insert (15) extending opposite the fixed contact (5).

16. Electric current cut-off device (50) according to the preceding claim, in which the magnetically conductive insert (16) comprises a first portion (17) extending parallel to the bearing surface (7) extended by a second portion (18) extending perpendicular to the bearing surface (7) towards the first portion (11) of the fixed contact (5).

17. Electric current cut-off device (50) according to the preceding claim, in which the first portion (17) of the magnetically conductive insert (16) comprises a recess (19) for the passage of a part of the second portion (12) of the fixed contact (5).

18. Medium voltage electrical apparatus (100), configured to selectively establish or cut off the current in a medium voltage electrical network comprising three phases (L1, L2 L3), comprising an electrical current cut-off device (50, 50', 50") according to one of the preceding claims arranged respectively on each of the phases (L1, L2, L3) of the electrical network.

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