Switching device for a medium voltage electrical device

Abstract

A switching device (30) is proposed for a medium voltage electrical apparatus (100), comprising: - a fixed contact (1), - a moving contact (2) configured to pivot about a pivot axis (R2) between: a first position (P1) in which the contacts (1,2) are separated, and a second position (P2) in which the contacts (1,2) are in contact, wherein the fixed contact (1) includes an arc guide (5) projecting from the fixed contact (1), the arc guide (5) being configured to be traversed by an electric arc generated at the establishment or interruption of the electric current between the fixed contact (1) and the moving contact (2), wherein the arc guide (5) includes two grooves (6) separated by a rib (7).

Description

technical field

[0001] This disclosure relates to the field of medium-voltage or high-voltage electrical equipment, i.e., a voltage range from 1 kV to over 52 kV. This equipment may be placed inside an insulating enclosure filled with a pressurized gas to improve electrical insulation properties and prevent unwanted electrical arcing within the insulating enclosure. Previous technique

[0002] Some electrical devices, such as circuit breakers, include a switching device for each phase of the electrical network, allowing for the alternating establishment and interruption of the electrical current. These switching devices have a moving contact, for example, a rotating contact, which can make contact with a fixed contact to establish the electrical current. The moving contact can also be separated from the fixed contact to interrupt the current flow.

[0003] Both during the establishment and interruption of the electric current, an electric arc can form between the fixed and moving contacts when they are close together. This electric arc causes significant heating of the contacts, particularly during current establishment by a short circuit. This heating can partially melt and damage the contacts. Repeated contact damage during the current establishment phases can render the switching device inoperable.

[0004] This disclosure aims to provide a solution to improve the reliability of medium voltage switching devices. Summary

[0005] To this end, the invention proposes a switching device for a medium-voltage electrical device, the switching device comprising: a fixed contact comprising one electrical conductor, a moving contact comprising two electrical conductors extending parallel to each other and at a distance from each other, the moving contact being configured to pivot about a pivot axis between: a first position in which the moving contact is separated from the fixed contact so as to prevent the flow of electric current between the contacts, and a second position in which the moving contact is in contact with the fixed contact so as to permit the flow of electric current between the contacts, in which the fixed contact includes an arc guide projecting from the electrical conductor of the fixed contact and directed towards the moving contact, the arc guide being configured to be traversed by an electric arc generated at the establishment of the electric current between the fixed contact and the moving contact, in which the arc guide includes two grooves separated by a rib.

[0006] An electric arc generated by bringing two electrical contacts at different electrical potentials into close proximity passes through the arc guide. The arc guide thus limits the heating of both the stationary and moving contacts, reducing the risk of damage to these contacts. The reliability of the switching device is improved.

[0007] The features listed in the following paragraphs can be implemented independently of each other or in any technically possible combination:

[0008] A passage of the moving contact from the first position, called the opening position, to the second position, called the closing position, corresponds to a phase of establishing the electric current in the breaking device.

[0009] A passage of the moving contact from the second position, called the opening position, to the second position, called the closing position, corresponds to a phase of interruption of the electrical current in the interruption device.

[0010] The arc guide is configured to channel an electric arc. In other words, an electric arc generated during the establishment of the electric current passes through the arc guide.

[0011] The two electrical conductors of the moving contact are linked in rotation around a common axis of rotation.

[0012] The two electrical conductors of the moving contact are made of copper.

[0013] The electrical conductor of the fixed contact is made of copper.

[0014] The electric arc guide is made of extra hard steel, for example a steel with a carbon content between 1% and 2%.

[0015] Alternatively, any other metal with good resistance to high temperatures, significantly higher than that of copper, can be used.

[0016] According to one embodiment of the cutting device, the grooves extend parallel to each other, in a direction parallel to the pivot axis of the moving contact.

[0017] The depth of a groove can be greater than the width of the rib.

[0018] According to one example of implementation, the bottom of the grooves has a semi-circular profile.

[0019] According to one aspect of the breaking device, the moving contact extends along a main direction perpendicular to the pivot axis.

[0020] According to one embodiment of the switching device, the moving contact includes a first reinforcing element, the first reinforcement element comprising a first portion bearing on the first electrical conductor of the moving contact and a second portion extending perpendicularly to the first portion towards the second electrical conductor of the moving contact, in which a lateral edge of the second portion of the first reinforcement element extends parallel to the axis of rotation of the moving contact.

[0021] An electric arc generated by the establishment of the electric current between the fixed contact and the moving contact passes from the lateral edge of the first reinforcing element to the rib of the electric arc guide.

[0022] The lateral edge of the second portion of the first reinforcing element is distant from the end of the electrical conductor opposite the axis of rotation.

[0023] The first reinforcement element includes, for example, a plate.

[0024] The first reinforcing element is metallic.

[0025] The first reinforcement plate is formed from a folded metal strip.

[0026] The first reinforcement plate, for example, is made of steel.

[0027] The first reinforcement plate has a U-shaped profile.

[0028] According to one aspect of the cutting device, the lateral edge of the second portion of the first reinforcing element is successively opposite a first groove, the rib, then a second groove during a passage of the moving contact from the first position to the second position.

[0029] A minimum distance between the rib and the lateral edge of the second portion of the first reinforcement element is less than 3.0 millimeters.

[0030] This distance allows the electric arc to be initiated in a controlled manner between the moving contact and the electric arc guide, with at least part of the electric arc passing through the lateral edge of the second portion of the first reinforcing element.

[0031] According to one embodiment of the switching device, the moving contact includes a second reinforcing element, the second reinforcement element comprising a first portion bearing on the second electrical conductor of the moving contact and a second portion extending perpendicularly to the first portion in the direction of the first electrical conductor of the moving contact, in which a lateral edge of the second portion of the second reinforcement element extends parallel to the axis of rotation of the moving contact.

[0032] According to one embodiment, the lateral edge of the second portion of the first reinforcement element and the lateral edge of the second portion of the second reinforcement element extend in line with each other.

[0033] The second reinforcement element includes, for example, a plate.

[0034] According to one aspect of the cutting device, the lateral edge of the second portion of the second reinforcing element is successively screwed into the first groove, the rib, and then the second groove during a passage of the moving contact from the first position to the second position.

[0035] A minimum distance between the rib and the lateral edge of the second portion of the second reinforcement element is less than 3.0 millimeters.

[0036] This distance allows the electric arc to be initiated in a controlled manner between the moving contact and the electric arc guide.

[0037] The first reinforcement plate and the second reinforcement plate are mirror images of each other.

[0038] According to one aspect of the breaking device, the electrical conductor of the fixed contact comprises two contact portions in mechanical contact with the moving contact when the moving contact is in the second position, known as the closing position, and the electric arc guide is distant from the two contact portions.

[0039] Thus, the heating generated by the passage of the electric arc occurs in a part of the fixed contact separate from the portions through which the electric current flows in steady state. Damage to the areas of the fixed contact involved in steady-state current conduction is therefore reduced, which improves the reliability of the switching device.

[0040] According to one example of an embodiment of the cutting device, the rib extends transversely along a width, the grooves extend transversely along a width, and the width of the rib is between 50% and 100% of the width of the grooves.

[0041] According to one embodiment of the cutting device, the electric arc guide includes a second rib located between a first lateral edge of the arc guide and a first groove.

[0042] According to one embodiment of the cutting device, the electric arc guide includes a third rib located between a second lateral edge of the arc guide and a second groove.

[0043] This configuration allows the electric arc to pass through the first rib, then jump over the groove separating the first rib from the second rib, and then jump again to the third rib, skipping the second groove. At any given moment, the electric arc is formed between a given rib and the moving contact. The electric arc does not pass through two separate ribs simultaneously. The alternating ribs and grooves allow for better control of the electric arc's location. The heat generated in the arc guide by the electric arc is thus better controlled, which reduces damage to the arc guide.

[0044] According to an example of the implementation of the proposed cutting device, one face of the first rib, one face of the second rib and one face of the third rib extend in the same plane.

[0045] The common plane of extension of the three ribs is parallel to the axis of rotation of the moving contact and perpendicular to the main axis of extension of the moving contact.

[0046] The three ribs can have the same width.

[0047] The width of a rib can differ from one rib to another.

[0048] According to one aspect of the switching device, the electric arc guide includes: a first connection zone between the rib and a first groove, a second connection zone between the rib and the second groove, and a minimum radius of curvature of the profile of the connecting areas is less than 0.2 millimeters.

[0049] In other words, the junctions between the rib and the grooves defining that rib are angular, not rounded. These junctions form sharp edges. The rib is thus clearly defined. The electric arc is therefore preferentially guided towards the rib, rather than towards the grooves bordering it.

[0050] According to one aspect of the switching device, the electric arc guide includes: a third connection zone between the second rib and the first lateral edge of the bow guide, and a minimum radius of curvature of the profile of the third connection zone is greater than 0.5 millimeter.

[0051] According to one aspect of the switching device, the electric arc guide includes: a fourth connection zone between the third rib and the second lateral edge of the bow guide, and a minimum radius of curvature of the profile of the fourth connection zone is greater than 0.5 millimeters.

[0052] According to one example of the implementation of the cutting device, the electric arc guide is fixed to the electric conductor of the fixed contact by a screw passing through the electric arc guide.

[0053] The electric arc guide includes a hole for a fixing screw.

[0054] The electric arc guide includes a slot for an anti-rotation pin.

[0055] According to one aspect of the breaking device, the moving contact includes a guide bar configured to allow movement of the first and second conductors relative to each other. This movement can be, depending on the operating phases, a bringing of the first conductor closer to the second conductor, or a moving of the first conductor away from the second conductor.

[0056] The moving contact includes an elastic element configured to apply a restoring force tending to bring the first electrical conductor and the second electrical conductor closer together.

[0057] The moving contact includes a spacer configured to maintain a minimum distance between the first electrical conductor and the second electrical conductor.

[0058] According to one embodiment of the switching device, in which the electrical conductors of the moving contact are configured to be moved relative to each other in a direction parallel to the axis of rotation, the breaking device includes a mechanical guide rigidly linked to the electrical conductor of the fixed contact, the mechanical guide being configured to be in contact with both electrical conductors of the moving contact during part of a travel from the first position to the second position of the moving contact, the mechanical guide having a beveled profile of decreasing width as a distance with the electrical conductor of the fixed contact increases, so as to progressively separate the two electrical conductors of the moving contact from each other during a passage from the first position to the second position of the moving contact.

[0059] The mechanical guide separates the two electrical conductors of the moving contact before they reach the fixed contact, thus facilitating the insertion of the fixed contact between the electrical conductors of the moving contact. This reduces mechanical shocks and friction associated with the insertion of the fixed contact, thereby minimizing mechanical wear on both the fixed and moving contacts. The reliability and lifespan of the switching device are improved. Furthermore, the insulating properties of the mechanical guide promote the localization of the electric arc on the arc guide ribs.

[0060] The mechanical guide has a first bearing face configured to receive the first electrical conductor of the moving contact and a second bearing face configured to receive the second electrical conductor of the moving contact, and a distance between the two bearing faces gradually decreases as a distance with the electrical conductor of the fixed contact increases.

[0061] The mechanical guide is made of electrically insulating material.

[0062] The mechanical guide is formed from a material with a low coefficient of friction.

[0063] The bearing faces of the mechanical guide have recesses.

[0064] According to one embodiment of the cutting device, the mechanical guide includes a housing for receiving a portion of the electric arc guide.

[0065] The mechanical guide can be overmolded onto the electric arc guide.

[0066] The mechanical guide receiving housing comprises a base bordered by three lateral faces.

[0067] The receiving housing for the mechanical guide may have a shape complementary to a portion of the electric arc guide.

[0068] The electric arc guide is positioned between the mechanical guide and the electrical conductor of the fixed contact.

[0069] The mechanical guide includes a hole for the fastener screw. The mechanical guide also includes a bearing surface against which the head of the fastener screw rests. The bearing surface of the mechanical guide and the receiving recess extend in parallel planes. The bearing surface is recessed from the edge of the mechanical guide. This recess is greater than the thickness of the screw head. The screw head is therefore itself recessed from the edge of the mechanical guide. In other words, the screw head is in contact with insulating material in all directions perpendicular to the screw axis. This configuration prevents an electric arc from forming between the moving contact and the screw head.

[0070] According to one embodiment of the switching device, the electrical conductor of the fixed contact includes a U-shaped curved portion, and the electric arc guide is fixed to the U-shaped curved portion.

[0071] The electrical conductor of the fixed contact comprises two parallel portions connected to each other by a connecting portion.

[0072] The connecting portion has a semi-circular shape.

[0073] The fixing screw and the anti-rotation pin extend in a direction parallel to the two parallel portions of the electrical conductor of the fixed contact.

[0074] The invention also relates to a medium voltage electrical device, configured to circulate an electric current in a medium voltage electrical network comprising three phases, the electrical device comprising a switching device as described above disposed respectively on each phase. Brief description of the drawings

[0075] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which: There figure 1is a schematic representation of a medium-voltage electrical device, The figure 2 is a general, perspective view of an electrical device incorporating a switching device according to the invention, the switching device being in the open position, The figure 3 is a general, perspective view of the electrical apparatus of the figure 2 With the shut-off device in the closed position, the figure 4 is a detailed, perspective view of one embodiment of the proposed switching device, The figure 5 is another detailed, perspective view of the switching device of the figure 4 , There figure 6 represents detailed views of a fixed contact of the switching device Figures 4 and 5 , There figure 7 represents other detailed, perspective views of elements of the switching device Figures 4 and 5 , There figure 8 is another detailed, perspective view of an element of the switching device Figures 4 and 5, There figure 9 is a detailed, side view of an element of the switching device Figures 4 and 5 , There Figure 10 is a detailed, front view of the cutting device Figures 4 and 5 . Description of the implementation methods

[0076] To facilitate the reading of the figures, the different elements are not necessarily drawn to scale. In these figures, identical elements bear the same references. Some elements or parameters may be indexed, that is, designated, for example, as first element or second element, or first parameter and second parameter, etc. This indexing aims to differentiate similar, but not identical, elements or parameters. This indexing does not imply any priority of one element or parameter over another, and the designations can be interchanged. When it is specified that a device includes a given element, this does not exclude the presence of other elements in that device.

[0077] We have schematically represented on the figure 1 a 100 medium voltage electrical device.

[0078] The medium-voltage electrical device 100 is configured to circulate an electric current in a medium-voltage electrical network comprising three phases Ph1, Ph2, Ph3. The electrical device 100 includes a switching device 30, 30', 30" according to the invention, disposed respectively on each phase Ph1, Ph2, Ph3. Each switching device 30, 30', 30" comprises respectively a fixed contact 1, 1', 1" and a moving contact 2, 2', 2". The three switching devices 30, 30', 30" are integral with a common actuator 50 allowing simultaneous control of the three switching devices 30, 30', 30". The switching devices 30, 30', 30" of the electrical device 100 may be identical.

[0079] The proposed 30 cutoff device is a cutoff device for a 100 medium voltage electrical device, and will be described in detail below.

[0080] The proposed 30 cut-off device includes: a fixed contact 1 comprising an electrical conductor 3, a moving contact 2 comprising two electrical conductors 4A,4B extending parallel to each other and at a distance from each other. The movable contact 2 is configured to pivot about a pivot axis R2 between a first position P1 in which the movable contact 2 is moved away from the fixed contact 1 so as to prevent the flow of electric current between contacts 1, 2, and a second position P2 in which the moving contact 2 is in contact with the fixed contact 1 so as to allow an electric current to flow between the contacts 1,2. The fixed contact 1 includes an arc guide 5 protruding from the electrical conductor 3 of the fixed contact 1 and directed towards the moving contact 2, the arc guide 5 being configured to be traversed by an electric arc generated at the establishment of the electric current between the fixed contact 1 and the moving contact 2, and the arc guide 5 includes two grooves 6 separated by a rib 7.

[0081] An electric arc is generated by bringing two electrical contacts 1 and 2 close together at different electrical potentials. The generated electric arc passes through the arc guide 5, and not directly from one contact to the other. The arc guide 5 thus limits the heating of the fixed contact 1 and the moving contact 2, and reduces the risk of damage to these contacts. The reliability of the switching device 30 is improved.

[0082] A transition of the moving contact 2 from the first position P1, known as the opening position, to the second position P2, known as the closing position, corresponds to a phase of establishing the electric current in the switching device 30. Conversely, a transition of the moving contact 2 from the second position P2, known as the closing position, to the first position P1, known as the opening position, corresponds to a phase of interrupting the electric current in the switching device 30.

[0083] There figure 3 represents the cutting device 30 in the second position P2, known as the closed position. figure 2 , THE Figures 4 and 5 and the Figure 10 represent the cutting device 30 in a position Pi intermediate between the opening position P1 and the second position P2. On the figure 2, a passage from the first position P1, called the opening position, to the second position P2, called the closing position, corresponds to a rotation of the moving contact 2 with respect to the pivot axis R2 in a clockwise direction.

[0084] The two electrical conductors 4A, 4B of the moving contact 2 are rotationally linked around a common axis of rotation R2. Both electrical conductors 4A, 4B of the moving contact 2 are made of copper. The two electrical conductors 4A, 4B of the moving contact 2 are commonly referred to as 'conducting blades'.

[0085] Each electrical conductor 4A, 4B of the moving contact 2 has a general straight bar shape. The straight bar is flattened. Each electrical conductor 4A, 4B extends along a longitudinal direction, called the principal direction of extension, corresponding to the length of the electrical conductor. Each electrical conductor 4A, 4B extends along a transverse direction, perpendicular to the longitudinal direction, corresponding to the width of the electrical conductor. On the figures 2 to 4The direction L2 is parallel to the longitudinal direction of the electrical conductors 4A and 4B, and the direction T2 is parallel to the transverse direction of the electrical conductors 4A and 4B. A direction E2 perpendicular to both the longitudinal direction L2 and the transverse direction T2 corresponds to the thickness of the electrical conductors 4A and 4B. The thickness of each electrical conductor is less than 30% of its width. The width of each electrical conductor 4A and 4B is less than 30% of its length.

[0086] Each electrical conductor 4A, 4B comprises two parallel faces. These two faces are parallel to the plane formed by the longitudinal direction L2 and the transverse direction T2. ​​Thus, the two faces are perpendicular to the pivot axis R2. Each electrical conductor 4A, 4B comprises a first face 4A-i, 4B-i, called the inner face, facing the other electrical conductor 4B, 4A. In other words, the inner face of one electrical conductor 4A, 4B is opposite the inner face of the other electrical conductor 4B, 4A. Each electrical conductor 4A, 4B also comprises a second face 4A-e, 4B-e, called the outer face, which is the face opposite the inner face. During the establishment of the electric current, corresponding to a transition from the first position P1 to the second position P2, the electrical conductor 3 of the fixed contact 1 is inserted between the two electrical conductors 4A, 4B of the moving contact 2.When electrical contact is established, the electrical conductor 3 of the fixed contact 1 is in mechanical contact with the electrical conductor 4A of the moving contact 2, as well as with the electrical conductor 4B of the moving contact 2.

[0087] The electrical conductor 3 of the fixed contact 1 is made of copper. The fixed contact 1 includes a heat sink 29 fixed to the electrical conductor 3. The heat sink 29, itself made of copper, increases the thermal inertia of the fixed contact 1, and therefore reduces its heating.

[0088] The arc guide 5 is configured to guide an electric arc. In other words, an electric arc generated during the establishment of the electric current passes through the arc guide 5. Similarly, an electric arc generated during the interruption of the electric current passes through the arc guide 5. figure 3This schematically illustrates the passage of an electric arc. Each arrow indicated by the symbol A represents a portion of the electric arc.

[0089] The arc guide 5 is made of extra-hard steel, for example, a steel with a carbon content between 1% and 2%, the percentage being a mass percentage. Alternatively, any other metal with good resistance to high temperatures, significantly higher than that of copper, may be used.

[0090] According to the illustrated example, particularly on the figure 4 , the grooves 6 extend parallel to each other, in a direction parallel to the pivot axis R2 of the moving contact 2.

[0091] The grooves 6 each form a blind recess. Two consecutive grooves 6 are separated by a portion of material, forming a rib 7.

[0092] The moving contact 2 extends along a principal direction L2 perpendicular to the pivot axis R2.

[0093] There figure 9 The diagram details the electric arc guide 5 in isolation, in profile view. The depth p6 of a groove 6 may be greater than the width l7 of the rib 7. The depth p6 of a groove may vary from one groove to another. According to the example shown, one bottom of the grooves 6 has a semi-circular profile.

[0094] The grooves 6 are obtained, for example, by machining. The shape of the groove bottom is then the complementary shape to that of the cutter used to form the grooves. Alternatively, the grooves 6 can be obtained by molding. In this case, the shape of the grooves 6 corresponds to the complementary shape to that of the counterpart formed in the mold.

[0095] According to the illustrated example, and as depicted on the figure 4 , there figure 5 , and the Figure 10The moving contact 2 includes a first reinforcing element 9A. The first reinforcing element 9A has a first portion 11A bearing on the first electrical conductor 4A of the moving contact 2 and a second portion 12A extending perpendicularly to the first portion 11A towards the second electrical conductor 4B of the moving contact 2. A lateral edge 13A of the second portion 12A of the first reinforcing element 9A extends parallel to the axis of rotation R2 of the moving contact 2.

[0096] As shown schematically on the figure 4 , an electric arc generated by the establishment of the electric current between the fixed contact 1 and the moving contact 2 passes from the lateral edge 13A of the first reinforcing element 9A to the rib of the electric arc guide 5.

[0097] The lateral edge 13A of the second portion 12A of the first reinforcing element 9A is located away from the end of the electrical conductor 4A opposite the axis of rotation R2. The lateral edge 13A of the second portion 12A of the first reinforcing element 9A is set back from the end of the moving contact 2 located opposite the axis of rotation R2, so as to allow the passage of the moving contact 2 without touching the electric arc guide 5 during the rotation of the moving contact 2.

[0098] The first reinforcing element 9A includes, for example, a plate. The first reinforcing element 9A is metallic. The first reinforcing plate 9A is formed from a folded metal strip. The first reinforcing plate 9A is, for example, made of steel.

[0099] The first reinforcing plate 9A has a U-shaped profile. The first portion 11A of the first reinforcing element 9A forms the base of the U-profile. The base of the U rests on the outer lateral face 4A-e of the first electrical conductor 4A of the moving contact 2. The second portion 12A forms the first wing of the U-profile. A third portion 12A' forms the second wing of the U-profile. The second portion 12A and the third portion 12A' extend in parallel planes.

[0100] The lateral edge 13A of the second portion 12A of the first reinforcing element 9A is successively opposite a first groove 6, the rib 7, and then a second groove 6 during a passage of the moving contact 2 from the first position P1 to the second position P2. During this rotational movement from the first position P1 to the second position P2, each point of the lateral edge 13A of the second portion 12A of the first reinforcing element 9A describes a circular arc trajectory, the center of this circular arc being located on the pivot axis R2.

[0101] The minimum distance between rib 7 and lateral edge 13A of the second portion 12A of the first reinforcing element 9A is less than 3.0 millimeters. This minimum distance is obtained for a given angular position of the moving contact 2. This minimum distance allows for controlled initiation of the electric arc between the moving contact 2 and the arc guide 5. At least a portion of the electric arc passes through the lateral edge 13A of the second portion 12A of the first reinforcing element 9A.

[0102] Similarly, the moving contact 2 includes a second reinforcing element 9B. The second reinforcing element 9B has a first portion 11B bearing on the second electrical conductor 4B of the moving contact 2 and a second portion 12B extending perpendicularly to the first portion 11B towards the first electrical conductor 4A of the moving contact 2. A lateral edge 13B of the second portion 12B of the second reinforcing element 9B extends parallel to the axis of rotation R2 of the moving contact 2.

[0103] According to the illustrated example, particularly on the figure 4 , the lateral edge 13A of the second portion 12A of the first reinforcement element 9A and the lateral edge 13B of the second portion 12B of the second reinforcement element 9B extend in line with each other.

[0104] The second reinforcement element 9B includes, for example, a plate. The first reinforcement plate 9A and the second reinforcement plate 9B are symmetrical to each other with respect to a plane perpendicular to the pivot axis R2. The first reinforcement plate 9A and the second reinforcement plate 9B are mirror images of each other.

[0105] The second reinforcement plate 9B thus has a U-shaped profile. The base of the U rests on the external lateral face 4B-e of the second electrical conductor 4B of the moving contact 2. The second portion 12B forms a first wing of the U-shaped profile, and a third portion 12A' forms a second wing of the U-shaped profile.

[0106] The lateral edge 13B of the second portion 12B of the second reinforcement element 9B is successively screwed into the first groove 6, the rib 7, then the second groove 6 during a passage of the movable contact 2 from the first position P1 to the second position P2.

[0107] A minimum distance between rib 7 and lateral edge 13B of the second portion 12B of the second reinforcing element 9B is less than 3.0 millimeters. As with the first reinforcing element 9A, this minimum distance allows for controlled initiation of the electric arc between the moving contact 2 and the arc guide 5. At least a portion of the electric arc passes through the lateral edge 13B of the second portion 12B of the second reinforcing element 9B.

[0108] The electrical conductor 3 of the fixed contact 1 comprises two contact portions 8A, 8B in mechanical contact with the moving contact 2 when the moving contact 2 is in the second position P2, known as the closing position, and the electric arc guide 5 is distant from the two contact portions 8A,8B.

[0109] In other words, the two contact portions 8A, 8B in mechanical contact with the moving contact 2 when the moving contact 2 is in the second position P2 are separated from the electric arc guide 5. These two contact portions 8A, 8B are the portions through which the electric current passes in steady current flow regime.

[0110] Thus, the heating generated by the passage of the electric arc occurs in a part of the fixed contact 1 distinct from the portions 8A, 8B through which the electric current flows in steady state. Damage to the areas 8A, 8B of the fixed contact 1 involved in the conduction of current in steady state is therefore reduced, which improves the reliability of the switching device 30.

[0111] The two contact portions 8A, 8B of the electrical conductor 3 are visible on the figure 2, in which the moving contact 2 is in a position distinct from the closed position P2. The two contact portions 8A, 8B are not visible on the figure 3 , because they are masked by mobile contact 2.

[0112] According to one embodiment of the cutting device 30, the rib 7 extends transversely over a width l7, the grooves 6 extend transversely over a width l6, and the width l7 of the rib 7 is between 50% and 100% of the width l6 of the grooves 6.

[0113] The transverse extension direction of the rib 7 and the grooves 6 is a direction perpendicular to both the pivot axis R2 and the main extension direction L2 of the moving contact 2. The longitudinal extension direction of the rib 7 and the grooves 6 is a direction parallel to the pivot axis R2.

[0114] According to the illustrated example, and as shown on the figure 9The electric arc guide 5 includes a second rib, denoted 7-2, located between a first lateral edge 10-1 of the arc guide 5 and a first groove, denoted 6-1. The electric arc guide 5 also includes a third rib, denoted 7-3, located between a second lateral edge 10-2 of the arc guide 5 and a second groove, denoted 6-2.

[0115] This configuration allows the electric arc, during the travel stroke that establishes the electric current, to pass through the second rib 7-2, then jump over the groove 6-1 separating the second rib 7-2 from the first rib 7, and then jump again to the third rib 7-3, jumping over the second groove 6-2. At any given instant, the electric arc is formed between a given rib and the moving contact 2. The electric arc does not pass through two separate ribs simultaneously. The alternating ribs and grooves allow for better control of the electric arc's location. The dissipation of heat generated in the arc guide 5 by the electric arc is thus better controlled, which reduces damage to the arc guide 5.

[0116] According to the illustrated example, and as shown on the figure 8, a face 14-1 of the first rib, a face 14-2 of the second rib and a face 14-3 of the third rib extend in the same plane P7. The common extension plane P7 of the three ribs is parallel to the axis of rotation R2 of the moving contact 2 and perpendicular to the main extension axis L2 of the moving contact 2.

[0117] The three ribs 7 can have the same width l7. The width l7 of one rib can differ from one rib to another.

[0118] The 5-piece electric arc guide includes: a first connecting zone 21-1 between the rib 7 and a first groove 6, a second connecting zone 21-2 between the rib 7 and the second groove 6, and a minimum radius of curvature of the profile of the connecting zones 21-1,21-2 is less than 0.2 millimeters.

[0119] In other words, the connection zones 21-1, 21-2 between the rib 7 and the grooves 6 delimiting this rib 7 are angular and not rounded. These connection zones 21-1, 21-2 form sharp edges. The rib 7 is thus clearly defined. The electric arc is therefore preferentially guided towards the rib 7, rather than towards the grooves 6 bordering this rib 7. The position of the electric arc is thus better controlled.

[0120] The 5-piece electric arc guide includes: a third connecting zone 21-3 between the second rib 7 and the first lateral edge 10-1 of the arc guide 5, and a minimum radius of curvature of the profile of the third connection zone 21-3 is greater than 0.5 millimeter.

[0121] Similarly, the electric arc guide 5 includes: a fourth connecting zone 21-4 between the third rib 7 and the second lateral edge 10-2 of the arc guide 5, and a minimum radius of curvature of the profile of the fourth connecting zone 21-4 is greater than 0.5 millimeter.

[0122] The areas delimiting the outer edges of the electric arc guide 5 are thus rounded, in order to avoid any risk of injury when mounting the electric arc guide on the electrical conductor 3 of the fixed contact 1.

[0123] In the illustrated example, the electrical conductor 3 of the fixed contact 1 includes a U-shaped curved portion 3-2, and the electric arc guide 5 is fixed to the U-shaped curved portion 3-2.

[0124] The electrical conductor 3 of the fixed contact 1 comprises two parallel portions 3-1, 3-3 connected to each other by a connecting portion 3-2. The connecting portion 3-2 has a semi-circular shape.

[0125] The electric arc guide 5 is fixed to the electrical conductor 3 of the fixed contact 1 by a screw 22 passing through the electric arc guide 5. The electric arc guide 5 includes an orifice 23 for the passage of a fixing screw 22.

[0126] According to the illustrated embodiment, the arc guide 5 includes a slot 25 for the passage of an anti-rotation pin 24. The fixing screw 22 and the anti-rotation pin 24, visible more particularly on the figure 6 , extend parallel to each other.

[0127] One end of the anti-rotation pin 24 is disposed in a complementary shaped orifice arranged in the electrical conductor 3 of the fixed contact 1. The opposite end of the anti-rotation pin 24 is protruding from the electrical conductor 3.

[0128] The fixing screw 22 and the anti-rotation pin 24 extend in a direction parallel to the two parallel portions 3-1, 3-3 of the electrical conductor 3 of the fixed contact 1.

[0129] As depicted in particular on the figure 4 , there figure 5 , and the Figure 10 The moving contact 2 includes a guide bar 18 configured to allow movement of the first conductor 4A and the second conductor 4B relative to each other. This movement can be, depending on the operating phases, a bringing of the first conductor 4A closer to the second conductor 4B, or a moving of the first conductor 4A further away from the second conductor 4B.

[0130] The moving contact 2 includes an elastic element 19 configured to apply a restoring force tending to bring the first electrical conductor 4A and the second electrical conductor 4B closer together. The elastic element 19 is a helical spring. One end of the spring 19 bears against a washer 31 attached to the guide bar 18. The other end of the spring 19 bears against the first portion 11A of the first reinforcing element 9A. A shoulder of the guide bar 18 bears against the first portion 11B of the second reinforcing element 9B.

[0131] The moving contact 2 includes a spacer 20 configured to maintain a minimum distance between the first electrical conductor 4A and the second electrical conductor 4B. The spacer 20 is positioned between the first electrical conductor 4A and the second electrical conductor 4B. The spacer is coaxial with the guide bar 18. The spacer 20 is tube-shaped, with the guide bar 18 passing through its center.

[0132] The axial surfaces of the spacer 20 respectively form a stop surface against which the electrical conductors 4A,4B of the moving contact 2 come to rest when the fixed contact 1 is moved away from the moving contact 2. Indeed, when the fixed contact 1 is not in contact with the electrical conductors 4A,4B, the spring 19 presses the electrical conductor 4A against a first axial surface of the spacer 20, and presses the electrical conductor 4B against a second axial surface of the spacer 20.

[0133] The cutting device 30 may include, in addition to the electric arc guide 5, a mechanical guide 15 facilitating the movement of the conductive knives 4A, 4B relative to each other during the electric current establishment phase.

[0134] Thus, according to the illustrated example, in which the electrical conductors 4A, 4B of the moving contact 2 are configured to be moved relative to each other in a direction parallel to the axis of rotation R2, the breaking device 30 includes a mechanical guide 15 rigidly linked to the electrical conductor 3 of the fixed contact 1. The mechanical guide 15 is configured to be in contact with the two electrical conductors 4A, 4B of the moving contact 2 during part of a travel from the first position P1 to the second position P2 of the moving contact 2L. The mechanical guide 15 has a beveled profile of decreasing width as the distance with the electrical conductor 3 of the fixed contact 1 increases, so as to progressively separate the two electrical conductors 4A, 4B of the moving contact 2 from each other during a passage from the first position P1 to the second position P2 of the moving contact 2.

[0135] The mechanical guide 15 separates the two electrical conductors 4A, 4B of the moving contact 2 before they reach the fixed contact 1. The distance between the two electrical conductors 4A, 4B thus increases progressively before and during the establishment of mechanical contact between the electrical conductors 4A, 4B of the moving contact 2 and the electrical conductor 3 of the fixed contact 1. This facilitates the insertion of the fixed contact 1 between the electrical conductors 4A, 4B of the moving contact 2. Mechanical shocks and friction associated with the insertion of the fixed contact 1 are therefore reduced. Mechanical wear of both the fixed contact 1 and the moving contact 2 is thus reduced. The reliability and service life of the breaking device 30 are improved. Furthermore, the insulating properties of the mechanical guide 15 promote the localization of the electric arc on the ribs 6 of the arc guide 5.

[0136] The mechanical guide 15 has a tapered profile, the thickest part of the profile being on the side of the electrical conductor 3 of the fixed contact 1, and the thinnest part being on the opposite side, i.e. the side closest to the moving contact 2 when it is in the P1 opening position.

[0137] The mechanical guide 15 has a first bearing face 16A configured to receive the first electrical conductor 4A of the moving contact 2 and a second bearing face 16B configured to receive the second electrical conductor 4B of the moving contact 2. The distance d between the two bearing faces 16A,16B gradually decreases as a distance D with the electrical conductor 3 of the fixed contact 1 increases.

[0138] The mechanical guide 15 has a general parallelepiped shape, with two opposite faces 16A and 16B being non-parallel. The mechanical guide 15 is located between the electrical conductor 3 of the fixed contact 1 and a virtual line of intersection between the first bearing face 16A and the second bearing face 16B.

[0139] The mechanical guide 15 is made of electrically insulating material. The mechanical guide 15 is formed from a material with a low coefficient of friction.

[0140] The bearing faces 16A, 16B of the mechanical guide 15 have recesses 26, particularly visible on the figure 7 .

[0141] According to the illustrated example, the mechanical guide 15 includes a receiving housing 17 for a portion of the electric arc guide 5. The receiving housing 17 of the mechanical guide 15 includes a base bordered by three lateral faces. Part A of the figure 7represents the mechanical guide 15, and part B of this figure represents the electric arc guide 5, the two elements being separate.

[0142] The receiving housing 17 of the mechanical guide 15 here has a shape complementary to a portion of the electric arc guide 5.

[0143] According to an embodiment not shown, the mechanical guide 15 can be overmolded onto the electric arc guide 5. In this case, the mechanical guide 15 and the electric arc guide 5 form a non-removable subassembly.

[0144] Part B shows the main components of fixed contact 1 in exploded view. Part B shows the same components assembled in a cross-sectional view.

[0145] The electric arc guide 5 is arranged between the mechanical guide 15 and the electrical conductor 3 of the fixed contact 1.

[0146] The fixing screw 22 passes successively through the mechanical guide 15 and the electric arc guide 5. The mechanical guide 15 includes a passage 27 for the fixing screw 22. The mechanical guide 15 includes a bearing surface 28 on which the head of the fixing screw 22 rests. The passage 27 formed in the mechanical guide 15 is aligned with the passage 23 formed in the electric arc guide 5. The bearing surface 28 of the mechanical guide 15 and the receiving housing 17 extend in parallel planes. The bearing surface 28 is set back from the edge of the mechanical guide 15. This setback is greater than the thickness of the head of the screw 22. The head of the screw 22 is therefore itself set back from the edge of the mechanical guide 15. In other words, the head of the screw 22 is opposite, in all directions perpendicular to the axis of the screw 22, an electrically insulating material.This configuration prevents an electric arc from forming between the moving contact 2 and the head of the screw 22.

[0147] The presence of the mechanical guide 15 on the switching device 30 is optional. According to the example shown here, the switching device 30 includes an arc flash guide 5 and a mechanical guide 15.

[0148] According to an embodiment not shown, the cutting device 30 includes a mechanical guide 15 but is not equipped with an electric arc guide.

[0149] In this case, a 30A cutoff device is proposed for a 100A medium-voltage electrical appliance, the 30A cutoff device comprising: a fixed contact 1 comprising an electrical conductor 3, a moving contact 2 comprising two electrical conductors 4A, 4B extending parallel to each other and at a distance from each other, the movable contact 2 being configured to pivot about a pivot axis R2 between: a first position P1 in which the moving contact 2 is separated from the fixed contact 1 so as to prevent the flow of electric current between the contacts 1,2, and a second position P2 in which the moving contact 2 is in contact with the fixed contact 1 so as to allow the flow of electric current between the contacts 1,2, in which the electrical conductors 4A,4B of the moving contact 2 are configured to be moved relative to each other in a direction parallel to the axis of rotation R2, and in which the breaking device 30 comprises a mechanical guide 15 rigidly linked to the electrical conductor 3 of the fixed contact 1, the mechanical guide 15 being configured to be in contact with the two electrical conductors 4A,4B of the moving contact 2 during part of a stroke of movement from the first position P1 to the second position P2 of the moving contact 2,the mechanical guide 15 having a beveled profile of decreasing width as the distance with the electrical conductor 3 of the fixed contact 1 increases, so as to progressively separate the two electrical conductors 4A,4B of the moving contact 2 from each other during a transition from the first position P1 to the second position P2 of the moving contact 2.

Claims

1. Switching device (30) for a medium-voltage electrical apparatus (100), the switching device (30) comprising: - a fixed contact (1) including an electrical conductor (3), - a moving contact (2) including two electrical conductors (4A, 4B) extending parallel to each other and at a distance from each other, the moving contact (2) being configured to pivot about a pivot axis (R2) between: a first position (P1) in which the moving contact (2) is separated from the fixed contact (1) so as to prevent the flow of electric current between the contacts (1, 2), and a second position (P2) in which the moving contact (2) is in contact with the fixed contact (1) so as to allow the flow of electric current between the contacts (1, 2), in which the fixed contact (1) includes an arc-shield (5) projecting from the electrical conductor (3) of the fixed contact (1) and directed towards the moving contact (2),the electric arc guide (5) being configured to be traversed by an electric arc generated at the establishment of the electric current between the fixed contact (1) and the moving contact (2), wherein the electric arc guide (5) comprises two grooves (6) separated by a rib (7).

2. Cutting device (30) according to claim 1, in which the grooves (6) extend parallel to each other, in a direction parallel to the pivot axis (R2) of the moving contact (2), and in which the moving contact (2) extends in a principal direction (L2) perpendicular to the pivot axis (R2).

3. Breaking device (30) according to claim 1 or 2, wherein the moving contact (2) comprises a first reinforcing element (9A), the first reinforcing element (9A) having a first portion (11A) bearing on the first electrical conductor (4A) of the moving contact (2) and a second portion (12A) extending perpendicularly to the first portion (11A) in the direction of the second electrical conductor (4B) of the moving contact (2), wherein a lateral edge (13A) of the second portion (12A) of the first reinforcing element (9A) extends parallel to the axis of rotation (R2) of the moving contact (2).

4. Breaking device (30) according to the preceding claim, wherein the moving contact (2) comprises a second reinforcing element (9B), the second reinforcing element (9B) having a first portion (11B) bearing on the second electrical conductor (4B) of the moving contact (2) and a second portion (12B) extending perpendicularly to the first portion (11B) in the direction of the first electrical conductor (4A) of the moving contact (2), wherein a lateral edge (13B) of the second portion (12B) of the second reinforcing element (9B) extends parallel to the axis of rotation (R2) of the moving contact (2).

5. Switching device (30) according to any one of the preceding claims, wherein the electrical conductor (3) of the fixed contact (1) comprises two contact portions (8A, 8B) in mechanical contact with the moving contact (2) when the moving contact (2) is in the second position (P2), referred to as the closing position, and wherein the electric arc guide (5) is distant from the two contact portions (8A,8B).

6. Cutting device (30) according to any one of the preceding claims, wherein the rib (7) extends transversely along a width (l7), wherein the grooves (6) extend transversely along a width (l6), and wherein the width (l) of the rib (7) is between 50% and 100% of the width (l6) of the grooves (6).

7. Cutting device (30) according to any one of the preceding claims, wherein the electric arc guide (5) comprises: - a second rib (7) included between a first lateral edge (10-1) of the arc guide (5) and a first groove (6), and - a third rib (7) included between a second lateral edge (10-2) of the arc guide (5) and a second groove (6).

8. A switching device (30) according to any one of the preceding claims, wherein the electrical conductors (4A, 4B) of the moving contact (2) are configured to be moved relative to each other in a direction parallel to the axis of rotation (R2), and wherein the switching device (30) comprises a mechanical guide (15) rigidly connected to the electrical conductor (3) of the fixed contact (1), the mechanical guide (15) being configured to be in contact with the two electrical conductors (4A, 4B) of the moving contact (2) during a portion of a travel from the first position (P1) to the second position (P2) of the moving contact (2), the mechanical guide (15) having a beveled profile of decreasing width as the distance from the electrical conductor (3) of the fixed contact (1) increases, so as to progressively separate the two electrical conductors (4A, 4B) from each other.4B) of the moving contact (2) during a transition from the first position (P1) to the second position (P2) of the moving contact (2).

9. Switching device (30) according to the preceding claim, wherein the mechanical guide (15) has a first bearing face (16A) configured to receive the first electrical conductor (4A) of the moving contact (2) and a second bearing face (6B) configured to receive the second electrical conductor (4B) of the moving contact (2), and wherein a distance between the two bearing faces (16A,16B) decreases progressively as a distance with the electrical conductor (3) of the fixed contact (1) increases.

10. Switching device (30) according to claim 8 or 9, wherein the mechanical guide (15) includes a receiving housing (17) for a portion of the electric arc guide (5), and wherein the electric arc guide (5) is disposed between the mechanical guide (15) and the electrical conductor (3) of the fixed contact (1).

11. Switching device (30) according to any one of the preceding claims, wherein the electrical conductor (3) of the fixed contact (1) comprises a U-shaped curved portion (3-2), and wherein the electric arc guide (5) is fixed to the U-shaped curved portion (3-2).

12. Medium voltage electrical apparatus (100), configured to circulate an electric current in a medium voltage electrical network comprising three phases (Ph1, Ph2, Ph3), the electrical apparatus (100) comprising a switching device (30,30',30") according to one of the preceding claims disposed respectively on each phase (Ph1, Ph2, Ph3).

Images