System for actuating vacuum bottles

Abstract

The invention relates to a system for actuating a vacuum bottle (1) of an electrical device, the vacuum bottle comprising a fixed electrode and a mobile electrode (2), the mobile electrode (2) being movable along a longitudinal axis (X) between a closed position and an open position. The actuation system comprises an adjusting nut (10), which is rotatable about the longitudinal axis (X) and driven by a driving device to perform an opening movement of the mobile electrode (2), and an adjusting screw (20), which is engaged with the adjusting nut (10) to change the moment when the driving device drives the mobile electrode (2). The mobile electrode (2) is constrained to translate along the longitudinal axis with the adjusting screw (20), but is free to rotate relative to the adjusting screw (20), and the rotation of the adjusting screw (20) is limited by a blocking device (9).

Description

Technical Field

[0001] The present invention relates to a system for actuating a vacuum bottle to open an electric circuit in a medium voltage or high voltage electrical device, which is a device operating at a voltage greater than 1000V.

[0002] The invention also relates to an electrical device comprising such an actuation system for at least one of its phases.In this document, the term electrical device equally denotes several types of devices, like interrupters, circuit breakers, contactors, fuse switches, reclosers, isolators and the like. Background Art

[0003] A medium or high voltage electrical device of the type described in EP2182536 comprises a vacuum bottle which is not placed in the main circuit comprising the main switch of the phases of the device, but in a branch connected in parallel with the main switch. Therefore, in normal operation, when the main switch is closed, no current flows through the vacuum bottle. Only during the opening operation of the main circuit is the bottle acted upon by the opening mechanism of the main switch, which makes it possible first to gradually switch the current from the main circuit to the branch and then to open the main switch while the current completely passes through the vacuum bottle. This is then opened again by the opening mechanism. The occurrence of an electrical switch arc in the main switch during the opening operation is thus avoided, since the vacuum bottle switches the main current.

[0004] Due to this construction, the vacuum bottle receives current only during the opening phase of the main phase circuit, and not during normal operation. In addition, the bottle is not acted upon during the closing operation of the main circuit, and it also does not have to withstand any short-circuit current. After switching the current in the main circuit, it must only withstand the transient recovery voltage (TRV).

[0005] This results in that the vacuum bottle can be advantageously simplified and designed to be much smaller in size than in a conventional structure in which the vacuum bottle would be placed in the main circuit of an electrical device.

[0006] EP3300097 has described a device that can drive the moving electrode of a vacuum bottle in such a product. The drive device is actuated, for example, by means of a moving blade via a moving contact of a main switch. The drive device then drives the moving electrode to the open position by means of an adjustment nut, which also enables a more precise adjustment of the movement of the moving electrode. The drive device comprises many small parts that require precise mechanical adjustment to obtain satisfactory system reproducibility. Torsional stresses may also sometimes be generated on the moving electrode.

[0007] One of the objects of the present invention is therefore to propose a simple solution for such a device for driving a mobile electrode, which is reliable, economical and easy to implement. It also aims to minimize the dielectric stresses of the system and likewise the torsional forces that can be applied to the bellows of the mobile electrode, in particular during implementation. Summary of the invention

[0008] To this end, the present invention describes a system for actuating a vacuum bottle of an electrical device, the vacuum bottle comprising a fixed electrode and an electrode, the electrode being movable along a longitudinal axis between a closed position in which the two electrodes are in contact with each other and an open position in which the two electrodes are separated, the actuation system comprising an adjustment nut, the adjustment nut being rotatably movable about the longitudinal axis and being driven by a drive device to perform an opening movement of the mobile electrode. According to the present invention, the actuation system comprises an adjustment screw engaged with the adjustment nut to change the moment when the drive device drives the mobile electrode, the mobile electrode being constrained to translate along the longitudinal axis with the adjustment screw but freely rotating relative to the adjustment screw, and the rotation of the adjustment screw being limited by a blocking device.

[0009] According to another feature, the mobile electrode comprises a transverse groove extending around the mobile electrode, and the adjusting screw comprises a fastening device inserted into the groove. The fastening device comprises a plurality of fastening clips, the ends of which are inserted into the groove.

[0010] According to one feature, the actuation system comprises a baffle placed between the vacuum bottle and the adjusting screw, and the baffle comprises an electrical contact of the electric spring type electrically connected to the moving electrode, the moving electrode being able to slide relative to the electric spring. The baffle is fixed to the vacuum bottle by a fixing clip and is connected to an external power supply lead.

[0011] According to another feature, the blocking means comprise a pin fixed to the support of the vacuum bottle, passing through the baffle and blocking the rotation of one of the fastening clips.

[0012] According to another feature, the adjusting screw includes external threads that engage with internal threads of the adjusting nut.

[0013] The invention also describes an electrical device comprising a main phase switch and such a system for actuating a vacuum bottle placed in parallel with the main phase switch.

[0014] In the case of a multiphase electrical installation (eg three-phase), which therefore has a main switch for each phase, the installation preferably comprises a vacuum bottle in parallel with each main switch and therefore comprises a vacuum bottle actuation system for each phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other features will become apparent from the following detailed description given with reference to the accompanying drawings, in which:

[0016] Figure 1A general perspective view showing the mechanism of a vacuum bottle for actuating a phase of an electrical device,

[0017] Figure 2 shows a partial cross-sectional side view of an embodiment of an actuation mechanism according to the present invention,

[0018] Figure 3 Shows Figure 2 A partial cross-sectional top view of the mechanism in

[0019] Figure 4 Detail of the end of the moving electrode showing the adjustment screw without the actuation mechanism, and

[0020] Figure 5 and Figure 4 Same, but with adjustment screw. DETAILED DESCRIPTION

[0021] Reference Figures 1 to 3 , a medium or high voltage electrical device comprises a main phase switch and a vacuum bottle 1 placed in parallel with the main switch. The vacuum bottle 1 is fixed to an insulating support 5 in a known manner and comprises a conductive mobile electrode 2 (also called mobile rod) and a conductive fixed electrode (also called fixed rod, not visible in the figure). The mobile electrode 2, which is generally rod-shaped, passes through a cover 6 of the vacuum bottle 1. It moves along a longitudinal axis X between a so-called closed position in which the two electrodes are in contact with each other and a so-called open position in which the two electrodes are separated. In all the figures of this document, the mobile electrode 2 is shown in the closed position.

[0022] The vacuum bottle further comprises a bellows seal 7, which is fixed to the moving electrode 2 and the cover 6. The bellows 7 is a fragile element, which is essential for sealing the interior of the vacuum bottle, so any distortion that may occur, for example, when a rotational force is applied to the moving electrode 2 must be avoided. In addition, since the structure of the proposed switch device only requires a small vacuum bottle, the bellows seal 7 is particularly fragile.

[0023] The mobile electrode 2 of the vacuum bottle 1 is driven by an actuation system which enables the opening movement of the vacuum bottle to be performed, i.e., from a closed position to an open position. To perform a reverse closing movement, i.e., from an open position to a closed position, the mobile electrode 2 can be driven, for example, by a return spring not shown in the figure.

[0024] The actuation system comprises a drive device comprising a blade 15 that is rotatably movable about a transverse axis 19 during the opening movement and a ring 16 that is rigidly connected to the blade 15 by two lateral links 17. During the opening operation of the main phase switch of the electrical connection device, the drive device moves under the action of an opening mechanism (not shown in the figure) of the main phase switch that acts on the blade 15. Thus, Figure 1Arrows are shown which represent the thrust exerted by the opening mechanism on the blade 15 and the connecting rod 17 during the opening movement of the vacuum flask 1 .

[0025] The actuation system further comprises an adjusting nut 10 made of insulating material, which is connected to the mobile electrode 2 and can be rotated by means of an internal thread to adjust its position relative to the mobile electrode 2. During the opening movement, the ring 16 of the drive device first abuts against the edge 11 of the adjusting nut 10 (see Figure 2 ), and then pushes the adjusting nut 10 along the axis X to pull the mobile electrode 2 towards the opening position. Advantageously, the adjusting nut 10 thus serves both to transmit the movement of the opening mechanism to the mobile electrode 2 and to adjust in a simple manner the precise moment at which the mobile electrode and the fixed electrode of the vacuum bottle will separate by acting on the engagement between the adjusting nut 10 and the mobile electrode 2.

[0026] The connection between the adjusting nut 10 and the moving electrode 2 is as follows Figure 2 and 3 According to the invention, the actuation system comprises an adjusting screw 20 made of an insulating plastic material, such as polyamide 6.6. The adjusting screw 20 has a hollow cylindrical shape and has a first portion provided with an external thread 21 and an opposite second portion provided with means 22 for fastening the mobile electrode 2.

[0027] The external thread 21 engages with the internal thread of the adjusting nut 10 to vary the adjustment of the adjusting nut 10 relative to the moving electrode 2. Turning the adjusting nut 10 slightly in one direction or the other changes the distance between the ring 16 and the edge 11 of the adjusting nut 10, and thus changes the moment at which the ring 16 will come into contact with the adjusting nut 10 and thus changes the moment at which the moving electrode 2 will begin its opening movement.

[0028] The fastening means 22 advantageously make it possible to limit the translation of the adjusting screw 20 with the mobile electrode 2 along the longitudinal axis X, while leaving the mobile electrode 2 free to rotate relative to the adjusting screw 20 about the axis X. Therefore, the adjusting screw 20 does not generate any rotational stress on the mobile electrode 2 and therefore there is no risk of damaging the bellows seal 7. The bellows seal 7 generates the only rotational stress on the mobile electrode 2.

[0029] To this end, in the embodiment shown, the mobile electrode 2 comprises a free end 3 and a transverse groove 4 extending around the shaft of the mobile electrode 2 close to the end 3. The fastening means are formed by a plurality of fastening clips 22, the ends of which are inserted into the groove 4 to rigidly connect the adjusting screw 20 and the mobile electrode 2.

[0030] In the example shown in the figures, the adjusting screw 20 comprises three fastening clips 22, which are evenly distributed around the cylindrical body of the adjusting screw 20, the width of each clip corresponding to an arc between about 30° and 60° (for example about 45°). Having three evenly distributed fastening clips 22 particularly facilitates satisfactory centering of the adjusting screw 20 relative to the mobile electrode 2. The width is chosen so that the clips 22 are sufficiently elastic to be inserted into the groove 4, but are still sufficiently strong. Obviously, a different number of clips and / or clips of different widths that are equally suitable can be selected for the fastening device. The fastening device thus provides a simple solution for:

[0031] - easy mounting and assembly of the actuation system on the vacuum bottle, thanks to the elasticity of the clips 22, which makes it possible to insert them very quickly into the grooves 4 during mounting, and

[0032] - Since the end of the clip 22 can rotate in the groove 4 , the adjusting screw 20 and the moving electrode 2 are constrained to translate together only without rotational stress. Therefore, any rotation of the adjusting screw 20 is not transmitted to the moving electrode 2 .

[0033] Preferably, the free end 3 of the mobile electrode 2 is rounded, for example hemispherical, in order to avoid edges that could cause dielectric problems.

[0034] The actuation system also comprises a metal baffle 30 surrounding the rod of the mobile electrode 2. It is placed between the vacuum bottle 1 and the adjustment screw 20 and is fixed to the support 5 of the vacuum bottle 1, for example by two fixing brackets 32, see in particular Figure 3 and 5 This baffle 30 is in the form of a disk, the ends of which are rounded to avoid edges, and is electrically connected to the power supply lead 33. An O-shaped electrical contact of the electric spring type 31 is fitted inside the baffle 30. This electric spring 31 is wound around the mobile electrode 2 before the groove 4 to ensure satisfactory electrical contact, capable of withstanding 2000 A at 24 kV for 20 milliseconds, for example, while sliding the mobile electrode 2, i.e. without generating any rotational stress on the mobile electrode 2, again in order to prevent damage to the bellows 7.

[0035] The baffle 30 is a screen whose purpose is to attenuate the electric field in this area in order to provide dielectric protection for the electric spring and the walls of the vacuum bottle. It also serves to provide an electrical connection between the moving electrode 2 and the power lead 33 through the electric spring 31, which in turn is connected to the main moving contact of the electrical device.

[0036] In addition, the actuation system comprises a blocking device 9 to prevent or limit the rotation of the adjusting screw 20, so that the rotation of the adjusting nut 10 does not cause the rotation of the screw 20. For this blocking device, various solutions can be envisaged. A very simple solution shown in the embodiment of the figures comprises a pin 9 protruding from the insulating support 5 of the vacuum bottle 1 and passing through the baffle 30, which passes through a hole made in the baffle 30. This pin 9 is designed to rest on the inner edge 23 of one of the fastening clamps 22 when the adjusting screw 20 is mounted on the mobile electrode 2, thereby preventing it from turning in one direction. When the pin 9 comes into contact with the inner edge of another adjacent fastening clamp 22, the rotation of the adjusting screw 20 is also limited in the other direction. Other blocking devices 9 can be easily envisaged.

[0037] Finally, the actuation system comprises a movable band 12 which, once adjusted, fixes the position of the adjustment nut 10 relative to the mobile electrode 2 (see Figure 1 ). The strap 12 is introduced into two lateral projections 18 extending on either side of the ring 16. The strap 12 can be easily snapped into the projections 18 so that it can be kept in the blocking position once the adjustment has been made, and can also be easily removed when the operator wishes to adjust the position of the adjustment nut 10.

[0038] Once the band 12 is snapped into place, the adjustment nut 10 is stopped by the notches in the band 12, which engage with the teeth 13 of the adjustment nut 10 located around its periphery to prevent the nut 10 from rotating. The number of teeth / notches determines the size of the possible adjustment angle between the adjustment nut 10 and the moving electrode 2.

[0039] In order to make the adjusting nut 10 easier to turn during the adjustment process, the shape of its end portion can be selected so that it can be operated with a wrench or tool, such as Figure 1 The hexagon in the example.

[0040] According to the invention, in the case of a multiphase electrical connection device (for example three-phase), which therefore has a main switch for each phase, the device preferably comprises a vacuum bottle connected in parallel with each main switch and therefore comprises a vacuum bottle actuation system for each phase. However, in such a device, the opening mechanism acting on the vacuum bottle actuation system is common to all phases of the device.

Claims

1. An actuation system for a vacuum bottle (1) for actuating an electrical device, the vacuum bottle comprising a fixed electrode and a mobile electrode (2), the mobile electrode (2) being movable along a longitudinal axis (X) between a closed position in which the two electrodes are in contact with each other and an open position in which the two electrodes are separated, the actuation system comprising an adjusting nut (10) which is rotatable about the longitudinal axis (X) and driven by a driving device (15, 16, 17) to perform an opening movement of the mobile electrode (2), characterized in that: - the actuation system comprises an adjustment screw (20) engaged with an adjustment nut (10) in order to vary the moment at which the drive means drives the mobile electrode (2), - the adjusting screw (20) comprises fastening means (22) for the mobile electrode (2) allowing the mobile electrode (2) to be constrained to translate along the longitudinal axis (X) with the adjusting screw (20), but to be free to rotate relative to the adjusting screw (20), - The rotation of the adjusting screw (20) is limited by a blocking device (9).

2. The actuation system according to claim 1, characterized in that: The mobile electrode (2) comprises a transverse groove (4) extending around the mobile electrode (2), and the fastening device (22) is inserted into the groove (4).

3. The actuation system according to claim 2, characterized in that: The fastening device comprises a plurality of fastening clips, the ends of which are inserted into the grooves (4).

4. The actuation system according to claim 3, characterized in that: The blocking means comprises a pin which blocks rotation of one of the fastening clips.

5. The actuation system according to claim 4, characterized in that: The actuation system comprises a baffle (30) placed between the vacuum bottle (1) and the adjusting screw (20), and the baffle comprises an electrical contact of the electric spring type (31) electrically connected to the mobile electrode (2), the mobile electrode being able to slide relative to the electric spring.

6. The actuation system according to claim 5, characterized in that: The baffle (30) is fixed to the vacuum bottle (1) via a fixing clip (32) and is connected to an external power lead (33).

7. An actuation system according to any one of claims 5 to 6, characterized in that: The pin is fixed to the support (5) of the vacuum flask (1) and passes through the baffle (30).

8. The actuation system according to claim 1, characterized in that: The mobile electrode (2) comprises a circular end (3).

9. The actuation system according to claim 1, characterized in that: The adjusting screw (20) includes an external thread (21) engaged with an internal thread of the adjusting nut (10).

10. An electrical device comprising a main phase switch and a vacuum bottle (1) placed in parallel with the main phase switch, characterized in that: The electrical device comprises at least one actuation system according to any one of claims 1-9.

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