Control element for a moving electrode of a vacuum bulb switch

Abstract

The invention relates to a control element (13) for a moving electrode of a vacuum bulb switch, comprising: - a winding (21) having at least one first layer (211) of winding of a conductor around an axial direction; - at least one rigid spacer (31) disposed radially around the periphery of the first layer (211) of winding and extending substantially over the entire thickness of the winding (21); - a matrix (4) of dielectric material in contact with a lateral surface (311) of the spacer (31), with the periphery (213) of the first layer (211), and with a first axial end (215) of the first layer, the second axial end (216) of the first layer (211) being at least partially free. Figure to be published with the abstract: Fig. 1

Description

Title of the invention: Control element for a moving electrode of a vacuum bulb switch

[0001] The invention relates to electrical protection devices such as medium- and high-voltage contactors, circuit breakers, switches, and fast disconnectors, and in particular to vacuum lamps used on medium- and high-voltage networks for such switches. The use of vacuum lamps makes it possible to withstand high voltages with short contact distances while exhibiting low contact resistance in the closed state.

[0002] A vacuum tube generally comprises a fixed electrode and a moving electrode, the contact between the electrodes being made within a sealed enclosure. For a circuit breaker, the movement of the moving electrode is made possible by the use of a circuit breaker control comprising an opening coil, a closing coil, and a moving plate made of conductive material placed between these coils. The moving electrode is connected to the moving plate by a rod, generally made of insulation.

[0003] To operate the circuit breaker, a capacitive assembly is discharged into the corresponding coil. The current surge through the coil generates an electromagnetic pulse that induces eddy currents in the moving plate, whose electromagnetic field opposes that of the coil. The moving plate is then said to be "induced." A repulsive force thus appears between the energized coil and the armature, which allows the moving plate and the moving electrode connected to it to move.

[0004] The reaction force on the opening coil and its support induces detrimental vibrations during opening. In use, the reaction force on the opening coil and its support can deform or displace them within the frame of reference of the chassis that supports them. The winding of the opening coil conductor is generally enamel-coated to ensure insulation and electrical integrity of this winding. This enamel can be scratched, dented, and deformed during the use of the circuit breaker. Consequently, the air gap between the opening coil and the armature surface can become irregular. The air gap can vary during the circuit breaker's service life or exhibit variations due to its manufacturing process. An increased air gap leads to degraded electromechanical conversion efficiency, and the circuit breaker's opening speed may become progressively slower over time.

[0005] The invention aims to overcome one or more of these drawbacks. The invention thus relates to a control element for a movable electrode of a vacuum bulb switch, comprising: -a winding comprising at least a first layer of winding of a conductor around an axial direction; -at least one rigid spacer arranged radially around the periphery of the first winding layer and extending substantially over the entire thickness of the winding; -a matrix of dielectric material in contact with a lateral surface of the spacer, with the periphery of the first layer and with a first axial end of the first layer, the second axial end of the first layer being at least partially free.

[0006] The invention also relates to the following variants. Those skilled in the art will understand that each of the features of the following variants can be combined independently with the above features, without thereby constituting an intermediate generalization.

[0007] According to one variant, said spacer is positioned projecting along the axial direction relative to the die.

[0008] According to another variant, the second axial end of the first layer is positioned in the same plane perpendicular to said axial direction.

[0009] According to yet another variant, the rigid spacer comprises a flat support surface parallel to said plane perpendicular to said axial direction.

[0010] According to yet another variant, the control member comprises several other rigid spacers arranged radially around the periphery of the winding and distributed around the winding, said rigid spacers each having a flat bearing surface, the flat bearing surfaces being at the same distance along the axial direction with respect to said plane.

[0011] According to one embodiment, the winding comprises a second winding layer of a conductor around the axial direction, superimposed on the first winding layer, comprising a separate matrix element interposed between the first and second winding layers and comprising radially extending channels filled by said matrix.

[0012] According to yet another variant, said channels extend over at least 80% of the radial dimension of said first and second layers of windings.

[0013] According to another variant, said element has a constant thickness.

[0014] According to another embodiment, the winding comprises a second winding layer of a conductor around the axial direction superimposed on the first winding layer, comprising a connecting winding inclined with respect to the ortho-radial direction and ensuring continuity between the windings of the first and second layers, the control element further comprising a hub around which said first and second layers of windings are wound, said hub comprising a guide groove for said joining winding.

[0015] According to yet another variant, the matrix extends homogeneously between the spacer and the winding.

[0016] According to yet another variant, the winding comprises an electrical conductor covered with a dielectric of a different composition from the composition of the matrix.

[0017] According to one variant, the lateral surface of the spacer has reliefs in contact with said matrix.

[0018] The invention also relates to a control system for a mobile electrode, comprising a control element as defined above, comprising an armature fixed to said spacer.

[0019] According to one variant, the system includes another control element as defined above, and further includes a rigid spacer positioned axially between the respective spacers of the control elements and in contact with these respective spacers.

[0020] According to yet another variant, the system further comprises an actuator of a movable electrode equipped with a conductive armature positioned between the windings of said control members.

[0021] The invention further relates to a method for manufacturing a control element for a moving electrode of a vacuum bulb switch, comprising the steps of: -supply: <d'un moule comportant une face interne plane ; <d'un bobinage comportant au moins une première couche d'enroulement d'un conducteur autour d'une direction axiale, présentant une première extrémité axiale, et une deuxième extrémité axiale en contact avec la surface interne plane du moule et opposée à la première ; <d'une entretoise rigide disposée radialement à la périphérie de la première couche d'enroulement et s'étendant sensiblement sur toute l'épaisseur du bobinage ; -filling the mold with a matrix of synthetic dielectric material so as to come into contact with a lateral surface of the spacer, with the periphery of the first layer and with the first axial end of the first layer.

[0022] Other features and advantages of the invention will become clear from the following description, which is by way of example and not limitation, with reference to the accompanying drawings, in which:

[0023] [Fig-1] is a side cross-sectional view of an electrode control system mobile, comprising a control element according to an example of an embodiment of the invention;

[0024] [Fig.2] is an enlarged side cross-sectional view at the level of a control element;

[0025] [Fig.3] is a perspective view of a separating element;

[0026] [Fig.4] is a perspective view of a winding surmounted by an element separator and wrapped around a hub;

[0027] [Fig.5] is a perspective view of an example of a hub allowing passage from a winding to another superimposed winding;

[0028] [Fig.6] is a side cross-sectional view of a mold including windings in view of pouring a resin to form a control element according to the invention;

[0029] [Fig.7] is a side sectional view of a variant of the mold including windings for pouring resin to form a control element according to the invention;

[0030] [Fig.8] is a side cross-sectional view illustrating an example of a winding face configuration opposite the armature;

[0031] [Fig.9] is a side sectional view illustrating another example of configuration of one face of a winding opposite the armature;

[0032] [Fig. 10] is a side cross-sectional view illustrating yet another example of the configuration of a face of a winding opposite the armature.

[0033] Figure 1 is a side cross-sectional view of a control system 1 for a moving electrode of a vacuum ampoule switch. The vacuum ampoule comprises, in a manner known per se, a moving electrode and a fixed electrode which are to be selectively separated or brought into contact. Figure 2 is a detailed view of a control element 13, which is described in detail later.

[0034] The moving electrode, not shown here, is attached to an actuator 7 mounted to slide relative to an armature 12. The moving electrode is positioned in a vacuum bulb in a manner known per se. The actuator 7 comprises, in a manner known per se, an armature 71, onto which a magnetic flux is selectively applied to drive the actuator 7 in sliding along the direction X towards an electrically open or closed position.

[0035] The control system 1 here comprises a control element 13 for the moving electrode. The control element 13 includes a winding 21, a rigid spacer 31 and a matrix of dielectric material 4, typically a synthetic material.

[0036] The winding 21 is driven in a manner known per se to selectively generate a magnetic flux through the armature 71. The winding 21 comprises at least a first layer 211 of winding of an electrical conductor around an axial direction X.

[0037] The rigid spacer 31 is arranged radially around the periphery of the first winding layer 211 and extends substantially over the entire thickness of the winding 21.

[0038] The dielectric material matrix 4 is in contact with a lateral surface 311 of the spacer 31, with the periphery 213 of the first layer 211 and with a first axial end 215 of the first layer, the second axial end 216 of the first layer 211 being at least partially free.

[0039] As illustrated in [Fig. 8], the axial end 216 is only partially free, the matrix 4 being present in non-flat spaces between turns. As illustrated in [Fig. 9], the axial end 216 is only partially free, the matrix 4 being present to cover a portion of the turns set back from the most prominent turns.

[0040] Fig. 10 illustrates a configuration according to an independent aspect of the invention, namely that the axial end 216 is fully covered by the matrix 4.

[0041] Thus, the relative position between the second axial end 216 and the spacer 31 is perfectly defined, while ensuring good protection against short circuits between the turns of the first layer 211 and the turns of the second layer 212. Since the spacer 31 is used to fix the control element 13 to the armature 12, the relative position between the second axial end 216 and the armature 12 of the armature is also perfectly defined, regardless of any possible contraction of the matrix 4 during its manufacturing process. With the second axial end 216 facing the armature 71, their relative position is perfectly defined, so that the element 13 is also less subject to deviations in its characteristics during aging. The invention thus allows for compliance with a dimensional chain independent of the drawbacks of using a resin matrix, while benefiting from the mechanical and dielectric advantages of this resin.This allows for a position between the armature 71 and the coil 21 in which their relative spacing is as small as possible. The magnetic coupling efficiency between the armature 71 and the coil 21 is then optimal. Furthermore, the use of the spacer 31 allows the control element 13 to be attached with high precision to the armature 12. This enables the coordination of acceleration, damping, and locking functions throughout the entire stroke of the actuator 7. Since this stroke is short, it is important to have precise and reliable relative positioning of the locks, dampers, and coils.

[0042] The spacer 31 is typically made of metal or composite material and advantageously offers a rough surface. The matrix 4 can, for example, be made of epoxy resin to provide good mechanical rigidity.

[0043] To facilitate interfacing between the spacer 31 and other mechanical components, the spacer 31 is advantageously positioned in projection along the axial direction X relative to the die 4. The other mechanical components are, for example, the armature 12 or a mechanical link with another winding.

[0044] Advantageously, the second axial end 216 of the first layer 211 is positioned in the same plane (Y, Z) perpendicular to the axial direction X. A This configuration allows for optimal control of the distance between the turns of the winding 211 and the armature 71. Such a configuration can be easily obtained by placing the winding 211 in contact with a flat wall of a mold and filling this mold with a resin to form the matrix 4. An example of molding the matrix 4 will be detailed later.

[0045] Advantageously, the rigid spacer 31 has a flat bearing surface 312 parallel to the plane perpendicular to the axial direction X, the bearing surface 312 therefore being perpendicular to the axial direction X. Such a flat bearing surface 312 makes it easy to interface precisely with a mechanical link, here a spacer 16 intended to define an axial distance between the winding 21 and another winding 22. The winding 21 is intended here to control the movement of the armature 71 in one direction, the winding 22 being intended to control the movement of the armature 71 in the opposite direction.

[0046] In order to distribute the stresses and limit bending phenomena in the control element 13, it advantageously comprises several other rigid spacers 32 arranged radially around the periphery of the winding 21 and distributed around this winding 21. Each rigid spacer has a flat bearing surface as defined above. The flat bearing surfaces are equidistant along the axial direction X from the plane including the second axial end 216 of the first layer 211. Interfacing the rigid spacers with other mechanical elements is thus facilitated.

[0047] As illustrated in the example of Figures 1 and 2, the winding 21 advantageously comprises a second layer 212 of a conductor winding around the axial direction X, superimposed on the first winding layer. This second conductor winding layer 212 is electrically connected in series with the first winding layer 211. Such a configuration makes it possible to reduce the diameter of the coil 21 for a given flux. This allows the required current density to be reduced and the amplitude of the deformations of the coil 21 to be reduced when a control current is applied.

[0048] According to an independent aspect of the invention, the control member 13 advantageously comprises an element 5 distinct from the matrix 4 interposed between the first and second winding layers 211 and 212. An example of such an element 5 is illustrated in perspective in [Fig. 3]. Such an element 5 is intended to comprise radially extending channels 51 filled by the matrix 4. The channels 51 are thus intended to allow resin to flow between the layers 211 and 212 during the manufacturing process, preventing the formation of bubbles. Such an element 5 makes it possible both to ensure separation between the winding layers 21 and 22 in use and during resin flow in the manufacturing process.

[0049] To ensure optimal control of the thickness of the matrix 4 between the winding layers 211 and 212, the element 5 advantageously has a constant thickness between flat faces. The channels 51 are formed between tabs 52. The tabs 52 extend radially around a ring. The ring 53 advantageously provides mechanical support between the tabs 52 and positions the element 5 around a hub. The element 5 advantageously has a thickness between 0.5 and 20 mm, depending in particular on the viscosity of the resin used, if applicable.

[0050] Advantageously, the channels 51 extend over at least 80% of the dimension radial of the first and second layers of windings 211 and 212. Such a configuration thus allows the casting of a resin to form a dielectric matrix 4 between the layers 211 and 212 over most of the diameter of the coil 21.

[0051] According to an independent aspect of the invention, the winding 21 comprises at least the first and second winding layers 211 and 212 wound around the X-axis and superimposed. These layers 211 and 212 are electrically connected in series. A connecting winding is inclined with respect to the Y, Z plane. This connecting winding (not shown) allows the layers 211 and 212 to be linked to ensure continuity between these windings 211 and 212. The inclination allows for a gradual transition from the level of winding 211 to the level of winding 212. The connecting winding is advantageously made as a single unit with layers 211 and 212. Thus, the risk of deficiencies in an electrical connection between layers 211 and 212 is limited, for example, by avoiding connecting layers 211 and 212 by soldering.

[0052] To facilitate the positioning and retention of the joining winding during the manufacturing process and in service, the control member 13 advantageously comprises a hub 6 around which the first and second layers 211 and 212 are wound. An example of such a hub 6 is shown in perspective in [Fig. 5]. The hub 6 is shown in combination with the winding 211 and the element 5 in [Fig. 4]. The hub 6 advantageously comprises a guide groove 61 for the joining winding, typically defining its inclination.

[0053] The matrix 4 advantageously extends homogeneously between the spacer 31 and the winding 21 to ensure its mechanical strength. In order to promote the mechanical bond between the spacer and the matrix 4 after resin pouring, the lateral surface 311 of the spacer 31 has raised features to engage with the matrix 4. The raised features can be in the form of a high roughness (for example obtained by sandblasting) or in the form of geometric shapes (for example a thread).

[0054] As is known per se, the electrical conductor of the winding 21 is coated with a dielectric to prevent the formation of short circuits between the turns. The composition of this dielectric is different from that of the matrix 4. This dielectric is, for example, made of enamel.

[0055] In the example of the control system 1 illustrated, the armature 12 is fixed to the spacer 31. The fixing is ensured, for example, by means of a threaded rod. Such a threaded rod can be bolted onto the armature 12 and pass through the spacer 31.

[0056] As illustrated, the control system 1 includes another control member 14, the shape of which is substantially the symmetrical of the control member 13 with respect to a Y, Z plane. A rigid spacer 16 is positioned axially between the respective spacers of the control members 13 and 14. The rigid spacer 16 is here in contact with the respective spacers of the control members.

[0057] The armature 71 is positioned here between the windings of the control elements 13 and 14.

[0058] Figure 6 illustrates a side cross-sectional view of a mold 9 including windings for the purpose of casting a resin to form a control element according to the invention. The mold 9 comprises a chamber 90 into which a resin is to be poured. The mold 9 has a flat inner face 91, here the lower face. The winding 211 is placed in contact with the flat inner face 91. A shim 93 can be used to press the winding 211 against the face 91. Thus, the end 216 is not covered with resin and can therefore remain free. A rigid spacer 31 is also disposed in the mold 9, radially around the periphery of the layer 211. The spacer 31 extends substantially over the entire thickness of the winding 21. The spacer 31 can also protrude from the flat inner face 91.

[0059] The mold 9 may include centering recesses for the spacers 31. The mold 9 may also have a cylindrical shaft around which the winding 21 can be centered. Seals may be provided between the mold and centering elements, and more generally at any location likely to allow resin to pass through and thus affect demolding.

[0060] In this example, the winding 21 has a second winding 212, as detailed previously. The windings 211 and 212 are separated here by element 5.

[0061] a [Fig. 7] illustrates a side cross-sectional view of another mold 9 including windings for casting resin to form a control element according to the invention. The mold 9 further comprises a chamber 90 into which resin is to be poured. The mold 9 has a flat inner upper face 92, here the upper face. The winding 211 is placed in contact with the flat inner face 92 by means of a spacer 93 located at the bottom of the mold 9. Thus, the end 216 is not covered with resin and can therefore remain free. A rigid spacer 31 is also arranged in the mold 9, radially at the periphery of the layer 211. The spacer 31 extends substantially over the entire thickness of the winding 21. The spacer 31 can also protrude from the flat inner face 91.

[0062] The elements positioned in the mold 9 are of course compatible with the temperatures of the casting and drying of the resin.

[0063] The resin is poured into the enclosure 90, so as to come into contact with the lateral surface 311 of the spacer 31, with the periphery 213 of the first layer 211 and with the first axial end 215 of the first layer 211. The resin is intercalated between the layers 211 and 212, and covers the layer 212. After solidification of the resin, a control element as described above is thus obtained.

[0064] After molding, the external surfaces of the die 4 can be machined if stringent geometric tolerances need to be met.

Claims

Demands

1. Control element (13) of a moving electrode of a vacuum bulb switch, characterized in that it comprises: -a winding (21) having at least one first layer (211) of winding of a conductor around an axial direction; -at least one rigid spacer (31) disposed radially at the periphery of the first layer (211) of winding and extending substantially over the entire thickness of the winding (21); -a matrix (4) of dielectric material in contact with a lateral surface (311) of the spacer (31), with the periphery (213) of the first layer (211) and with a first axial end (215) of the first layer, the second axial end (216) of the first layer (211) being at least partially free.

2. Control member (13) according to claim 1, wherein said spacer (31) is positioned projecting along the axial direction relative to the die (4).

3. Control member (13) according to any one of the preceding claims, wherein the second axial end (216) of the first layer (211) is positioned in the same plane perpendicular to said axial direction.

4. Control member according to claim 3, wherein the rigid spacer (31) has a flat bearing surface (312) parallel to said plane perpendicular to said axial direction.

5. Control member according to claim 4, comprising several other rigid spacers (32) arranged radially around the periphery of the winding (21) and distributed around the winding, said rigid spacers each having a flat bearing surface, the flat bearing surfaces being at the same distance along the axial direction with respect to said plane.

6. Control member according to any one of the preceding claims, wherein the winding (21) comprises a second layer (212) of winding of a conductor around the axial direction, superimposed on the first winding layer, comprising a matrix element (5) distinct from the matrix interposed between the first and second winding layers (21, 22) and comprising radially extending channels (51) filled by said matrix (4).

7. Control member according to claim 6, wherein said channels (51) extend over at least 80% of the radial dimension of said first and second layers of windings.

8. Control element according to claim 6 or 7, wherein said element has a constant thickness.

9. Control member according to any one of the preceding claims, wherein the winding (21) comprises a second layer (212) of winding of a conductor around the axial direction superimposed on the first winding layer (211), comprising a junction winding inclined with respect to the ortho-radial direction and ensuring continuity between the windings of the first and second layers, the control member further comprising a hub (6) around which said first and second layers (211, 212) of windings are wound, said hub comprising a guide groove (61) for said junction winding.

10. Control member according to any one of the preceding claims, wherein the die (4) extends homogeneously between the spacer (31) and the winding (21).

11. Control member according to any one of the preceding claims, wherein the winding (21) comprises an electrical conductor covered with a dielectric of a different composition from the composition of the matrix (4).

12. Control member according to any one of the preceding claims, wherein the lateral surface (311) of the spacer (31) has reliefs in contact with said matrix (4).

13. Control system (1) of a movable electrode, comprising a control member according to any one of the preceding claims, comprising an armature (12) fixed to said spacer (31).

14. Control system (1) according to claim 12, comprising another control member (14) according to any one of the preceding claims 1 to 12, and further comprising a rigid spacer (16) positioned axially between the respective spacers of the control members and in contact with these respective spacers.

15. Control system (1) according to claim 12 or 13, further comprising an actuator (7) of a movable electrode equipped of a conductive armature (71) positioned between the windings of said control elements.

16. Method for manufacturing a control element for a moving electrode of a vacuum bulb switch, comprising the steps of: -supplying: <d’un moule comportant une face interne plane ; <d’un bobinage (21) comportant au moins une première couche (211) d’enroulement d’un conducteur autour d’une direction axiale, présentant une première extrémité axiale, et une deuxième extrémité axiale en contact avec la surface interne plane du moule et opposée à la première ; <d’une entretoise rigide (31) disposée radialement à la périphérie de la première couche (211) d’enroulement et s’étendant sensiblement sur toute l’épaisseur du bobinage (21) ; -remplissage du moule avec une matrice (4) en matériau diélectrique synthétique de façon à venir en prise avec une surface latérale (311) de l’entretoise (31), avec la périphérie (213) de la première couche (211) et avec la première extrémité axiale (215) de la première couche.

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