Power shut-off module with dielectric barrier

Abstract

The invention relates to a power shut-off module (10) comprising an insulating housing (2), two pairs of fixed contacts (3) and two movable contacts (4) rigidly attached to an item of movable equipment (5) that is movable in translation in the housing (2) between an open position and a closed position. The module is characterised in that it comprises an insulating shield device (50) having a fixed end rigidly attached to the housing (2) and a movable end rigidly attached to the item of movable equipment (5), and which has a length that is variable between an extended position when the item of movable equipment (5) is in the open position and a retracted position when the item of movable equipment (5) is in the closed position, in order to create a dielectric barrier between the fixed contacts of one and the same pair of fixed contacts (3).

Description

[0001]

[0002] The present invention relates to an electrical cut-off module comprising an electrically insulating housing, at least one pair of fixed contacts, including an upstream fixed contact and a downstream fixed contact, and at least one movable contact secured to equipment movable in translation in said housing relative to said at least one pair of fixed contacts between an open position and a closed position.

[0003] The present invention applies to current-breaking devices whose electrical contacts are opened by a linear translational movement of the movable contacts relative to fixed contacts. In such breaking modules, the electrical characteristics of the breaking device are determined in part by the air volume of the breaking chambers and the control of the dielectric separation between the fixed current-input electrical contacts and the fixed current-output electrical contacts. These electrical characteristics correspond to the capabilities of the breaking device to manage the electric arc that is generally created when the electrical circuit is opened, leading to its rapid extinction. The breaking chambers are delimited by the interior walls of the housing and comprise the fixed and movable contacts between which the electric arc is likely to be created.

[0004] Linear switching modules commonly comprise a movable bar, on which the movable contacts are mounted, of a length less than the useful length of the switching boxes, to allow it to travel its path between an open position and a closed position, and vice versa, without colliding with the box. Figure 1 illustrates an example of a switching module 1 of the state of the art comprising an electrically insulating box 2, of which only the lower half-box 20 is shown, two pairs of fixed contacts 3, and two movable contacts 4 mounted on a movable equipment, commonly called a movable bar 5 in translation along the arrow T. Figure 1 illustrates the switching module 1 in the open position, in which the movable contacts 4 are distant from the fixed contacts 3 and the electrical circuit is open.The end 5a of the movable bar 5 located on the right of Figure 1 is close to or against the corresponding transverse wall 22 of the housing, occupies the air volume of the CC breaking chamber and naturally forms a separation or dielectric barrier between the upstream fixed contact 3a and the downstream fixed contact 3b of the pair located on the right. Conversely, the end 5b of the movable bar 5 located on the left of Figure 1 is distant from the corresponding transverse wall 23 of the housing, releases the air volume of the CC breaking chamber, and exposes the upstream fixed contact 3a and the downstream fixed contact 3b of the pair located on the left to a possible re-breakdown of the electric arc E between them, as shown in Figure 2.In this left part of the box 2, the separation or dielectric barrier between the upstream fixed contact 3a and the downstream fixed contact 3b is therefore broken when the movable bar 5 is in the open position, which limits the electrical performance of the switching device and creates an electrical risk for people and equipment located downstream.

[0005] Publication EP 270 389 A1 describes a multi-pole rotary switch whose rotating movable bar includes a metal earthing screen, and which is said to provide a disconnecting function to maintain insulation between the input and output terminals of the switch. This solution is, however, limited to a rotary cut-off module, and unsuitable for a linear cut-off module.

[0006] Publications US 2 007 911 A and FR 2 694 444 A1 describe linear cut-off modules equipped with an electrically insulating screen device, the performance of which depends on the position of the movable bar. Description of the invention

[0007] The present invention aims to overcome these drawbacks by proposing a deformable dielectric barrier between the movable bar and the housing of the cut-off module so as to retain the dielectric qualities necessary to achieve the electrical performance targeted by said module, regardless of the position of the movable bar.

[0008] For this purpose, the invention relates to a cut-off module of the type indicated in the preamble, characterized in that it comprises an electrically insulating screen device, arranged in said housing between the upstream fixed contact and the downstream fixed contact of said at least one pair of fixed contacts, said screen device comprising a fixed end secured to said housing and a movable end secured to said movable equipment, and having a variable length between an extended position when said movable equipment is in the open position, and a retracted position when said movable equipment is in the closed position, to create a dielectric barrier between the upstream fixed contact and the downstream fixed contact of said at least one pair of fixed contacts.

[0009] In a first embodiment, said screen device may be of telescopic construction. In this case, it may comprise at least two segments, including a fixed segment secured to said housing and a movable segment secured to said movable equipment. It may also further comprise at least one intermediate segment sliding relative to the fixed segment and the movable segment.

[0010] In this embodiment, said screen device advantageously comprises translation stops arranged to define said extended position, and provided respectively between the different segments.

[0011] Preferably, said screen device and said housing respectively have complementary guide shapes arranged to guide in translation said movable segment and / or said intermediate sliding segment relative to said housing. In a second embodiment, said screen device may be rollable, and comprise at least one membrane wound around an axis of rotation integral with the housing, the membrane comprising a fixed end integral with the housing and a movable end integral with the mobile equipment.

[0012] In a third embodiment, said screen device may be extensible, and comprise at least one pleated membrane, the membrane comprising a fixed end secured to the housing and a mobile end secured to the mobile equipment.

[0013] Brief description of the drawings

[0014] The present invention and its advantages will appear better in the following description of several embodiments given as non-limiting examples, with reference to the appended drawings, in which:

[0015] Figure 1 is a perspective view of a cutting module according to the state of the art, in the open position, without the upper part of the housing, Figure 2 is a top view of the cutting module of Figure 1,

[0016] Figure 3 is a perspective view similar to that of Figure 1, showing a cut-off module according to the invention, in the open position, equipped with a screen device in the extended position,

[0017] Figure 4 is a view similar to that of Figure 3, showing the cut-off module in the closed position and the screen device in the retracted position, Figure 5 is an exploded view of the cut-off module of Figure 3,

[0018] Figure 6 is a cross-sectional view of the cut-off module of Figure 3,

[0019] Figure 7 is a sectional view along the horizontal section plane VII-VII of the left part of the cut-off module of Figure 3 in the open position, Figure 8 is a view similar to that of Figure 7 along the section plane VIII-VIII of the left part of the cut-off module of Figure 4 in the closed position,

[0020] Figure 9 is a sectional view along the vertical section plane IX-IX of the left part of the cut-off module of Figure 3 in the open position,

[0021] Figure 10 is a view similar to that of Figure 9 along the section plane XX of the left part of the cut-off module of Figure 4 in the closed position,

[0022] Figure 11 is an exploded view of a cut-off module and a screen device according to a first variant of the invention,

[0023] Figure 12 is a perspective view of the cut-off module of Figure 11 and the screen device in the open position,

[0024] Figure 13 is a perspective view of a cut-off module and a screen device according to a second variant of the invention, and

[0025] Figure 14 is a view similar to that of Figure 13 of a cut-off module and a screen device according to a third variant of the invention.

[0026] Description of the embodiments

[0027] In the illustrated embodiments, identical elements or parts bear the same reference numbers. Furthermore, terms that have a relative meaning, such as vertical, horizontal, right, left, front, rear, above, below, etc., must be interpreted under normal conditions of use of the invention, and as shown in the figures. The X, Y and Z axes are defined by an orthonormal reference system illustrated in Figure 1. Furthermore, the geometric positions indicated in the description and the claims, such as “perpendicular”, “parallel”, “symmetrical” are not limited to the strict sense defined in geometry, but extend to geometric positions that are close, that is to say which accept a certain tolerance in the technical field considered, without influence on the result obtained.This tolerance is notably introduced by the adverb “sensiblement”, without this term necessarily being repeated before each adjective.

[0028] With reference to Figures 3 to 14, the electrical cut-off module 10 according to the invention comprises an electrically insulating housing 2, consisting of two half-housings: a lower half-housing 20 and an upper half-housing 21, assembled and secured by any known means, such as screw-on fixing members (not shown). The cut-off module 10 comprises at least one pair of fixed contacts 3, and in the example illustrated two pairs of fixed contacts 3, each pair comprising an upstream fixed contact 3a and a downstream fixed contact 3b if the current flows from top to bottom in the figures. Each fixed contact 3 is conventionally constituted by a blade 30 made of electrically conductive material, and comprises a connection pad 31 external to the housing 2 provided with fixing holes 32 for a power cable (not shown).The cut-off module 2 comprises at least one movable contact 4, and in the example shown, two movable contacts 4, embedded and secured to a movable equipment 5, commonly called a movable bar. Each movable contact 4 is conventionally constituted by two blades 40 made of electrically conductive material, superimposed and secured to each other by a spring member 41 to form a clamp capable of fitting onto the corresponding blade 30 of the fixed contacts 3. This type of docking is called a sliding contact, without this example being limiting.

[0029] The mobile equipment 5 carrying the mobile contacts 4 is mounted in the housing 2 to be movable in translation along the arrow T relative to the pairs of fixed contacts 3 between an open position (figure 3) in which the electrical contacts are open and the electrical circuit is interrupted, and a closed position (figure 4) in which the electrical contacts are closed and the electrical circuit is established. The housing 2 and the mobile equipment 5 comprise for this purpose complementary interlocking shapes ensuring a translational guidance function in the longitudinal axis Y of the housing, such as grooves and ribs. They may also comprise end-of-travel stops to define the extreme positions of the mobile equipment 5, corresponding to the open position (fig. 3) and the closed position (fig. 4), such as shoulders of complementary shape.

[0030] Each pair of fixed contacts 3 and its corresponding movable contact 4 define between them a cut-off zone in which an electric arc is likely to extend, in particular when the electrical circuit is opened. The cut-off module 10 thus comprises at least one cut-off chamber, and in the example shown, two cut-off chambers CC, delimited by the interior walls of the housing 2 and each comprising a cut-off zone for managing the electric arc in order to cut the current.

[0031] The DC breaker chamber located on the right of the figures contains the mobile equipment 5 when it is in the open position. It thus occupies the air volume of this DC breaker chamber, isolates the upstream fixed contact 3a from the downstream fixed contact 3b, forms a dielectric barrier, and promotes the extinction of the electric arc and the breaking of the current.

[0032] The CC breaker chamber located on the left of the figures comprises, according to the invention, an electrically insulating screen device 50, added in the housing 2 between the upstream fixed contact 3a and the downstream fixed contact 3b to fulfill these same functions, namely to occupy the air volume of this CC breaker chamber, to isolate the upstream fixed contact 3a from the downstream fixed contact 3b, to form a dielectric barrier, and to promote the extinction of the electric arc and the breaking of the current.Let us recall that without this screening device 50, in accordance with figures 1 and 2, the electric arc E which forms respectively between the upstream fixed contact 3a and the movable contact 4, then between the movable contact 4 and the downstream fixed contact 3b, in particular when the electrical circuit is opened, risks moving and being installed directly between the upstream fixed contact 3a and the downstream fixed contact 3b, maintaining a flow of current while the cut-off module 1 is in the open position, resulting in a dangerous situation for people and equipment located downstream.In the example illustrated in Figures 3 to 10, the screen device 50 is of telescopic construction and comprises at least two segments, and in this example three segments 51, 52, 53, without this number of segments being limiting, arranged to slide relative to each other and adapt the length of the screen device 50 to the length of the CC breaking chamber according to the movement of the mobile equipment 5 between the two extreme positions. Thus, the screen device 50 is designed to have a variable length between two extreme positions, including an extended position when the mobile equipment 5 is in the open position, and a retracted position when the mobile equipment 5 is in the closed position, such that it performs its dielectric barrier functions regardless of the position of the mobile equipment 5.

[0033] The screen device 50 has a three-dimensional shape of the polyhedron type (see in particular FIGS. 5 and 6) to match the shapes of the inner walls of the housing 2 and occupy the majority of the volume of the CC breaking chamber. In addition, these three-dimensional shapes are complementary to those of the housing 2 and provide a translational guidance function in the longitudinal axis Y of the housing 2, such as grooves and ribs.

[0034] The screen device 50 comprises in this example:

[0035] - a fixed segment 51 secured to the housing 2,

[0036] - a mobile segment 53 secured to the mobile equipment 5, and

[0037] - an intermediate segment 52 sliding freely on the fixed segment 51 and in the movable segment 53, the section of the fixed segment 51 fitting into the section of the intermediate segment 52, and the section of the intermediate segment 52 fitting into the section of the movable segment 53. In this configuration, the fixed segment 51 is the smallest and housed inside, while the movable segment 53 is the largest and arranged outside the screen device 50. This example is not limiting, because an inverse configuration may also be suitable, that is to say that the movable segment is the smallest and housed inside, while the fixed segment is the largest and arranged outside the screen device (see figures 11 and 12).In this example of a screen device 50 of telescopic construction, the length of the segments 51, 52, 53 in the extended position must cover the total length of the CC extinguishing chamber when the mobile equipment 5 is in the open position, without discontinuity. And the length of these segments 51, 52, 53 must allow their overlap in the retracted position in the remaining volume of the CC extinguishing chamber when the mobile equipment 5 is in the closed position.

[0038] The fixed segment 51 consists of a hollow part comprising a front wall 54 and a peripheral wall 55 which extends perpendicularly from the front wall 54 in the direction of the mobile equipment 5 and in the longitudinal axis Y of the housing. The front wall 54 is adjacent to the corresponding transverse wall 23 of the housing. It is provided with a fixing lug 56 which fits into a corresponding notch 57 provided in the housing 2, to maintain this first segment in a fixed position and create the fixed point of the screen device 50. The fixing lug 56 may extend inside the fixed segment 51 or not, so as to serve or not as reinforcement.The peripheral wall 55 has a polygonal section, consisting of a plurality of facets at right angles to each other, to create U-shaped external ribs, including at least two lateral ribs 58, a lower rib 59 and an upper rib 60, respectively connected to each other by L-shaped shoulders 61. All or part of the free edge of the peripheral wall 55 comprises a translation stop 62, arranged to cooperate with a complementary translation stop provided on the intermediate segment 52. The translation stop 62 may be formed by a continuous or discontinuous rim, folded outwards, for example at a right angle. Any other equivalent means may be suitable.

[0039] The intermediate segment 52 consists of an annular part comprising a peripheral wall 63 which extends in the longitudinal axis Y of the housing. The peripheral wall 63 has a polygonal section complementary to that of the fixed segment 51, consisting of a plurality of sections at right angles to each other, to create lateral grooves 64, lower 65 and upper 66 on the one hand and lateral ribs 67, lower 68 and upper 69 on the other hand in the shape of a U, respectively connected to each other by L-shaped shoulders 70. The lateral grooves 64, lower 65 and upper 66 are arranged to slide axially on the lateral ribs 58, lower 59 and upper 60 of the fixed segment 51 by means of an operating clearance.All or part of the free edge of the peripheral wall 63 on the side of the fixed segment 51 comprises a translation stop 71 to cooperate with the translation stop 62 of the fixed segment 51, consisting of a continuous or discontinuous rim folded inwards and defining the extended position of the intermediate segment 52. The lower 68 and upper 69 ribs are arranged to slide axially in the lower 24 and upper 25 grooves of the housing 2 with an operating clearance. All or part of the free edge of the peripheral wall 63 on the side of the movable segment 53 comprises a translation stop 72 to cooperate with a complementary translation stop provided on the movable segment 53.

[0040] The mobile segment 53 is made up of two half-pieces, each comprising a three-dimensional side wall 73, one part of which (on the left in the figures) is solid and has interlocking shapes complementary to those of the corresponding face of the intermediate segment 52, and the other part (on the right in the figures) is openwork and comprises two superimposed windows 74, separated by a fixing bar 75. Thus, each side wall 73 of the mobile segment fits laterally onto the mobile equipment 5 to be fixed there by a screw 76 or any other equivalent fixing member, removable or not. To do this, the openwork part of each side wall

[0041] 73 fits over the blades 40 of the movable contact 4 which pass through the windows

[0042] 74 superimposed, and the solid part of each side wall 73 is cantilevered at the left end 5a of the mobile equipment 5 in the direction of the intermediate segment 52. Each side wall 73 of the mobile segment 53 has an inner groove 77 arranged to slide on the corresponding lateral rib 67 of the intermediate segment 52 by means of an operating clearance, and an outer groove 78 to free an axial passage for the blade 30 of the corresponding fixed contact 3 during the movement of the mobile equipment 5. All or part of the free edge of the side walls 73 of the mobile segment 53 has a translation stop 79 consisting of a continuous or discontinuous rim folded inwards to cooperate with the translation stop 72 of the intermediate segment 52, defining the extended position of the intermediate segment 52, and therefore of the entire screen device 50.

[0043] Furthermore, the combination of the U-shaped guide ribs and grooves, and the L-shaped shoulders provided respectively on the segments 51, 52, 53 of the screen device 50 also ensure the centering of the segments between them and relative to the housing 2.

[0044] The operation of the screen device 50 is simple and automatic. When the mobile equipment 5 is in the open position, the screen device 50 is in the extended position, as shown in Figures 3, 7, 9: the axial position of the segments 51, 52, 53 relative to each other being defined by the contact between the respective translation stops 62, 71 and 72, 79. When the mobile equipment 5 moves from the open position to the closed position, the screen device 50 folds into the retracted position, as shown in Figures 4, 8, 10. In its translation, the mobile equipment 5 moves with it the mobile segment 53 which slides on the intermediate segment 52 until it comes into contact with the translation stop 72 of the intermediate segment 52. Then, the mobile segment 53 pushes the intermediate segment 52 which slides on the fixed segment 51 until it comes into contact with the transverse wall 23 of the box 2.The mobile equipment 5 is then in the closed position, and the screen device 50 in the retracted position. In the opposite direction, when the mobile equipment 5 moves from the closed position to the open position, it carries with it the mobile segment 53 which slides on the intermediate segment 52 until it catches the translation stop 72 of the intermediate segment 52. Then, the mobile segment 53 pulls the intermediate segment 52 which slides on the fixed segment 51 until it catches the translation stop 62 of the fixed segment 51. The mobile equipment 5 is then in the open position, and the screen device 50 in the extended position. Of course, the architecture of the screen device 50 as described with reference to FIGS. 3 to 10, as well as its translational guiding means, its translational stops, its centering means, etc. are not limiting and any other technically equivalent embodiment may be suitable.

[0045] To illustrate the possible embodiments, Figures 11 and 12 show another screen device 80 of telescopic construction, consisting of three segments, including:

[0046] - a fixed segment 81 consisting of two parallel side walls 82, projecting axially from the transverse wall 23 of the housing 2, forming an integral part or not of the housing,

[0047] - a mobile segment 83 consisting of a middle wall 84, axially projecting from the mobile equipment 5, forming an integral part or not of the mobile equipment, and ending in a translation stop 85, and

[0048] - an intermediate segment 86 sliding freely in the fixed segment 81 and on the mobile segment 83.

[0049] The intermediate segment 86 is constituted as in the previous example of an annular part, comprising a peripheral wall 87 which extends in the longitudinal axis Y of the housing 2. The peripheral wall 87 has a polygonal section complementary to that of the housing 2, of the fixed segment 81 and of the movable segment 83, to ensure translational guidance and centering of the parts between them guaranteeing an operating clearance allowing their sliding. In the same way, the segments 81, 83, 86 comprise translational stops 85 allowing the passage of the screen device 80 from a retracted position in which the segments 81, 83, 86 are superimposed when the movable equipment 5 is in the closed position, to an extended position in which the segments 81, 83, 86 are end to end when the movable equipment 5 is in the open position (figure 12), and vice versa.In this variant, the movable segment 83 slides in the intermediate segment 86, and the intermediate segment 86 slides in the fixed segment 81. The intermediate segment 86 can further cooperate with translation stops provided in the housing 2 to define its extended position.

[0050] Figures 13 and 14 also illustrate, as non-limiting examples, other variant embodiments of the screen device 90, 100 according to the invention, which make it possible to ensure the same function as those described previously, to achieve the same result consisting of the creation of a dielectric barrier between the upstream fixed contact 3a and the downstream fixed contact 3b in the breaking chamber CC, regardless of the axial position of the mobile equipment 5.

[0051] In Figure 13, the screen device 90 is rollable. It comprises a flexible membrane 91 so that it can be rolled around a rotation axis 92 secured to the housing 2. The rotation axis 92 extends vertically, close to the transverse wall 23 of the housing, between the lower half-housing 20 and the upper half-housing (not shown). The rotation axis 92 is mounted in the housing so that it can rotate freely on itself, or comprises a double axis, including a first axis fixed to the housing and a second axis that can rotate about the first axis. The screen device 90 comprises a fixed end, corresponding to the inner end of the membrane 91 fixed to the rotation axis 92, and a movable end 93, corresponding to the outer end of the membrane 91 fixed to the mobile equipment 5 by any compatible fixing means.The movable end 93 of the membrane 91 can be pinched and glued between two jaws 94 fixed together by screws 95 or the like, the jaws 94 being integral with the corresponding left end 5a of the movable equipment 5. The screen device 90 further comprises a spring member (not shown) ensuring the winding of the membrane 91 around its axis of rotation 92. Thus, the membrane 91 unwinds under the effect of a traction exerted by the movable equipment 5 when it moves into the open position (figure 13) and winds automatically under the effect of its return member when the traction ceases and the movable equipment 5 moves into the closed position. In figure 14, the screen device 100 is extensible.It comprises a membrane 101 pleated in an accordion, forming a deformable bellows, between a fixed end 102 secured to the transverse wall 23 of the housing 2 by a fixing lug 103 fitted into the notch 57 of the housing, and a movable end 104 secured to the movable equipment 5 by any compatible fixing means, such as between two jaws 105 secured to the left end 5a of the movable equipment 5. Thus, the membrane 101 deploys or extends under the effect of traction exerted by the movable equipment 5 when it moves into the open position (figure 14) and folds or contracts automatically under the effect of its elasticity when the traction ceases and the movable equipment 5 moves into the closed position.

[0052] The present invention is of course not limited to the embodiments described but extends to any modification and variant obvious to a person skilled in the art within the limits of the appended claims. Furthermore, the technical characteristics of the different embodiments and variants mentioned above may be, in whole or in some cases, combined with each other.

Claims

Claims 1. Electrical cut-off module (10) comprising an electrically insulating housing (2), at least one pair of fixed contacts (3), including an upstream fixed contact (3a) and a downstream fixed contact (3b), and at least one movable contact (4) secured to a movable equipment (5) in translation in said housing (2) relative to said at least one pair of fixed contacts (3) between an open position and a closed position, cut-off module characterized in that it comprises an electrically insulating screen device (50, 80, 90, 100), arranged in said housing (2) between the upstream fixed contact (3a) and the downstream fixed contact (3b) of said at least one pair of fixed contacts (3), said screen device comprising a fixed end secured to said housing (2) and a movable end secured to said movable equipment (5), and having a variable length between an extended position when said movable equipment (5) is in the open position,and a retracted position when said mobile equipment (5) is in the closed position, to create a dielectric barrier between the upstream fixed contact (3 a) and the downstream fixed contact (3 b) of said at least one pair of fixed contacts (3)., 2. Electrical cut-off module according to claim 1, characterized in that said screen device (50, 80) is of telescopic construction.

3. Electrical cut-off module according to claim 2, characterized in that said screen device (50, 80) comprises at least two segments (51, 53; 81, 83), including a fixed segment (51, 81) secured to said housing (2) and a mobile segment (53, 83) secured to said mobile equipment (5).

4. Electrical cut-off module according to claim 3, characterized in that said screen device (50, 80) further comprises at least one intermediate segment (52, 86) sliding relative to the fixed segment (51, 81) and to the movable segment (53, 83).

5. Electrical cut-off module according to any one of claims 3 and 4, characterized in that said screen device (50, 80) comprises translation stops (62, 71, 72, 79; 85) arranged to define said extended position, and provided respectively between the different segments (51, 52, 53; 81, 83, 86).

6. Electrical cut-off module according to any one of claims 1 to 5, characterized in that said screen device (50, 80) and said housing (2) respectively have complementary guide shapes (24, 68; 25, 69) arranged to guide in translation said movable segment (53, 83) and / or said intermediate segment (52, 86) sliding relative to said housing (2).

7. Electrical cut-off module according to claim 1, characterized in that said screen device (90) is rollable, and comprises at least one membrane (91) wound around an axis of rotation (92) secured to the housing (2), the membrane (91) comprising a fixed end secured to the housing (2) and a mobile end (93) secured to the mobile equipment (5).

8. Electrical cut-off module according to claim 1, characterized in that said screen device (100) is extensible, and comprises at least one pleated membrane (101), the membrane (101) comprising a fixed end (102) secured to the housing (2) and a mobile end (104) secured to the mobile equipment (5).

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