Switching device for an electrical medium-voltage circuit

Description

technical field

[0001] The present invention relates to the field of medium-voltage current-switching devices, i.e., voltages above 1 kV and generally up to 52 kV, and currents on the order of 1000 to 3000 Amperes. The invention relates in particular to switching devices in which the current is interrupted by opening a vacuum tube arranged in series in a main branch of an electrical circuit. Previous technique

[0002] The vacuum tube comprises a movable electrode connected to a control rod. The control rod is connected to a control lever. The control lever is movable between two extreme positions, defining a constant actuation stroke. In both extreme positions, the control lever is locked and then unlocked according to the desired action: opening or closing the switching device. By actuating the control lever, the rod is moved, separating or bringing the movable electrode closer to the fixed electrode, thus opening or closing the electrical circuit.

[0003] When the circuit is closed, sufficient contact pressure must be ensured between the two electrodes of the vacuum bulb, in order to resist the repulsive forces existing between them due to the passage of current.

[0004] To ensure this contact pressure, at least one spring is present in the kinematic linkage between the control lever and the connecting rod, and the control lever's stroke is greater than the minimum stroke required to make contact with the vacuum ampoule electrodes. This excess stroke compresses the spring, thus applying the desired minimum contact pressure. This excess stroke is present in the linkage between the control lever and the connecting rod. Furthermore, the stroke required to make contact with the vacuum ampoule electrodes changes over time, due in particular to contact erosion and wear of the mechanism as the switching device is used. Consequently, the compression of the spring that creates the contact pressure also changes, meaning that the contact pressure varies throughout the product's lifespan.

[0005] To be able to alert the user when maintenance or replacement is required, it is crucial to be able to determine the pressure between the vacuum tube electrodes throughout the product's operation. The overtravel between the control lever and the control rod is directly correlated to the contact pressure. Therefore, monitoring this overtravel is essential. For this reason, some manufacturers choose to position the spring between the control lever and the control rod. This arrangement allows for easy access and visibility of the overtravel, outside of the live area, and facilitates the simple installation of a position sensor to monitor it.

[0006] On the other hand, minimizing the mass of the moving parts of the switching device located between the contact pressure spring and the moving contact is advantageous for achieving better circuit opening performance. Some manufacturers therefore choose to position the spring, which creates the desired contact pressure, as close as possible to the moving electrode, at the level of the control rod. The additional travel required to compress the spring is then no longer visible, making it difficult to easily integrate a position sensor.

[0007] The aim of the invention is to provide a solution that minimizes the mass of the moving parts of the device while allowing easy monitoring of overtravel throughout the use of the cutting device.

[0008] Document US2016 / 141136 discloses the pre-characterizing part of main claim 1. Summary

[0009] To this end, the invention proposes a device for switching off a medium-voltage electrical circuit, comprising: a vacuum bulb comprising a fixed electrode and a movable electrode, an actuating lever linked to the movable electrode, the actuating lever being movable between a first position called the opening position in which the movable electrode and the fixed electrode are separated by an opening distance, and a second position called the closing position in which the movable electrode and the fixed electrode are in contact so as to allow current to pass in the electrical circuit, a passage of the actuating lever from the first position to the second position defining a displacement stroke, an insulator linked to the actuating lever, a compression means, exerting a repulsive force between the moving electrode and the insulator, in which the stroke of the actuating lever is greater than the opening distance, the cutting device comprising: an indicator rod mechanically linked to the moving electrode, configured to extend at least partly outside the insulator when the actuating lever is in the closed position in which the indicator rod is radially outside the insulator, and in which the indicator rod passes through a guide plate.

[0010] Since the indicator rod is linked to the moving electrode, its position reflects the position of the moving electrode. The position of the indicator rod is easily determined because at least part of it is located outside the insulator and is therefore readily accessible. This allows for easy determination of the moving electrode's position. It is also possible to verify that the range of motion allows for sufficient contact pressure to be applied between the electrodes of the vacuum tube. If this contact pressure is insufficient due to electrode contact erosion, an alarm signal can be triggered. Corrective action can then be taken. For example, the cutoff device may need to be adjusted to restore sufficient range of motion to a control sleeve mechanically linked to the moving electrode.

[0011] The features listed in the following paragraphs can be implemented independently of each other or in any technically possible combination: The indicator rod is configured to indicate a distance between the moving electrode and the insulator.

[0012] The indicator rod is configured to indicate an overtravel of the actuating lever relative to the opening distance between the fixed electrode and the moving electrode.

[0013] According to one embodiment, the indicator rod is rigidly linked to the moving electrode.

[0014] Preferably, the indicator rod is electrically isolated from the moving electrode.

[0015] According to one embodiment of the cutting device, the indicator rod is electrically insulating.

[0016] The indicator stem is made of epoxy resin, or polyester.

[0017] According to one embodiment, the cutting device includes a control sleeve attached to the moving electrode, and the compression means exerts a repulsive force between the control sleeve and the insulator so as to press the control sleeve against the insulator when the moving electrode is away from the fixed electrode.

[0018] The compression device is an elastic restoring force. For example, the compression device is a spring. The spring could be a helical spring.

[0019] The mobile electrode is mobile in translation along a longitudinal axis.

[0020] The actuating lever is movable in rotation around a transverse axis. The transverse axis is perpendicular to the longitudinal axis.

[0021] The insulator includes a housing for receiving the control socket.

[0022] The reception area extends along the longitudinal axis.

[0023] The compression means exerts a restoring force between the control sleeve and the insulator so as to press the control sleeve against a stop in the receiving housing when the moving electrode is away from the fixed electrode.

[0024] The compression device is a helical spring extending along the longitudinal axis.

[0025] The stop has an opening for the control sleeve.

[0026] The stop extends transversely to the longitudinal axis.

[0027] The control sleeve has a shoulder configured to bear against the stop.

[0028] According to one embodiment of the switching device, the insulator extends along a longitudinal axis, and the indicator rod is parallel to the longitudinal axis.

[0029] According to one embodiment of the switching device, the insulator is linked to a control plate comprising a pivot extending along an axis transverse to the longitudinal axis, The actuating lever is linked to the pivot of the control plate, the insulator is linked to the control plate by a screw-nut adjustment system configured to adjust the relative position of the insulator with respect to the control plate, so as to adjust the opening distance between the moving electrode and the fixed electrode when the actuating lever is in the first position, and the indicator rod passes through the screw-nut adjustment system.

[0030] The insulator is positioned between the moving electrode and the adjustment system.

[0031] The indicator stem may include a cylindrical portion and a set of fins extending transversely to the cylindrical portion.

[0032] The fins are disc-shaped.

[0033] The fins are offset along the cylindrical portion of the indicator stem.

[0034] The distance between two consecutive fins is constant.

[0035] The indicator rod is connected to the control socket by a connecting bar.

[0036] The connecting bar extends in the transverse direction.

[0037] For example, the connecting bar and the indicator rod form a single unit.

[0038] The guide plate extends transversely to the indicator rod.

[0039] The guide plate is attached to the control plate.

[0040] According to one type of implementation, a portion of the indicator rod is opposite a position sensor rigidly linked to the control plate.

[0041] The indicator rod has a magnetic target.

[0042] The magnetic target is positioned at one axial end of the indicator rod.

[0043] The magnetic target is a permanent magnet.

[0044] The position sensor is a Hall effect sensor.

[0045] An axial end of the indicator rod is flush with an edge of an indicator rod passage orifice when the actuating lever is in the open position. Brief description of the drawings

[0046] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which: [ Fig. 1 ] is a cross-sectional view of a cutting device not forming part of the invention [ Fig. 2 ] is another cross-sectional view of the switching device of the figure 1 , [ Fig. 3 ] is a partial, cross-sectional view of the cutting device of the figure 1 , [ Fig. 4] is another partial, cross-sectional view of the switching device of the figure 1 , [ Fig. 5 ] is a cross-sectional view of a cutting device according to the invention, [ Fig. 6 ] is a partial, cross-sectional view of the cutting device of the figure 5 , [ Fig. 7 ] is a perspective view of a cutting device according to the first embodiment of the invention. Description of the implementation methods :

[0047] 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 subsystem contains a given element, this does not exclude the presence of other elements in that subsystem. Similarly, when it is specified that a subsystem includes a given element, it is understood that the subsystem includes at least that element.

[0048] We have represented on the figure 1a switching device 50 of a medium voltage electrical circuit 30, i.e. from 1 to 52 kV. The switching device 50 comprises a vacuum bulb 1 arranged in series in an electrical circuit 30.

[0049] The vacuum tube 1 comprises a fixed electrode 2 and a movable electrode 3. The fixed electrode 2 extends along a longitudinal axis X. The fixed electrode 2 and the movable electrode 3 are coaxial. Each electrode 2, 3 has a disc-shaped portion extending transversely to the longitudinal axis X. The disc-shaped portion of the movable electrode 3 can be in contact with the disc-shaped portion of the fixed electrode 2, so as to allow the passage of electric current between the electrodes, and thus into the vacuum tube 1. The movable electrode 3 is free to move in translation along the longitudinal axis X.

[0050] An actuating lever 4 controls the opening or closing of the vacuum bulb 1, and thus of the electrical circuit 30. The actuating lever 4 is movable in rotation about a transverse axis Y. The transverse axis Y is perpendicular to the longitudinal axis X.

[0051] A control plate 11 includes a pivot 12 extending along an axis Y1 transverse to the longitudinal axis X. The actuating lever 4 is connected to the pivot 12 of the control plate 11. An insulator 5 is integral with the control plate 11. More precisely, the insulator 5 is rigidly connected to the control plate 11. The insulator 5 isolates the control plate 11 from the voltage of the electrical circuit 30. The actuating lever 4 comprises two parallel arms 40a, 40b connected to each other. figure 7 details this aspect of the system.

[0052] The present invention proposes a device for cutting off 50 a medium voltage electrical circuit 30, comprising: a vacuum bulb 1 comprising a fixed electrode 2 and a movable electrode 3, an actuating lever 4 linked to the movable electrode 3, the actuating lever 4 being movable between a first position called the open position P1 in which the movable electrode 3 and the fixed electrode 2 are separated by an opening distance D1, and a second position called the closed position P2 in which the movable electrode 3 and the fixed electrode 2 are in contact so as to allow current to flow in the electrical circuit 30, a movement of the actuating lever 4 from the first position P1 to the second position P2 defining a displacement stroke C1, an insulator 5 linked to the actuating lever 4, a compression means 7, exerting a repulsive force between the movable electrode 3 and the insulator 5, in which the stroke C1 of the actuating lever 4 is greater than the opening distance D1, the cutting device comprising: an indicator rod 8 mechanically linked to the moving electrode 3, configured to extend at least partly outside the insulator 5 when the actuating lever 4 is in the closed position P2.

[0053] The difference between the stroke C1 of the actuating lever 4 and the opening distance D1 is called the overtravel. This overtravel ensures contact pressure between the fixed electrode 2 and the moving electrode 3. The stroke C1 of the actuating lever 4 is greater than the opening distance D1, such that the moving electrode 3 is further away from the insulator 5 when the actuating lever 4 is in the closed position P2. The term "far away" means that the distance along the X-axis between the moving electrode 3 and the insulator 5 is different when the actuating lever 4 is in the closed position P2 and when the actuating lever 4 is in the open position P1.

[0054] The opening distance D1 between the electrodes of the vacuum bulb 1 is referenced on the figure 1 The stroke C1 of the actuating lever 4 is referenced on the figure 2 . There figure 1 corresponds to the opening position P1 of the actuating lever 4, and the figure 2This corresponds to the closed position P2. The range of motion of the actuating lever 4 has been exaggerated to simplify the representation. When the electrical circuit 30 is closed, the actuating lever 4 pivots around the Y-axis under the effect of a control bar, not shown, inserted into a housing 34 in the actuating lever 4. The control bar thus passes through each of the arms 40a, 40b of the actuating lever 4. The range of motion C1 of the lever 4 is determined by the construction of the control bar mechanism. This range of motion C1 is fixed. The range of motion C1 of the actuating lever 4 is chosen to be greater than the stroke required to bring the moving electrode 3 closer to the fixed electrode 2. Thus, the movement of the actuating lever 4 from the open position P1 to the closed position P2 allows the compression device 7 to be compressed.Other types of kinematic linkages between the control bar and the actuating lever 4 can of course be implemented. The opening distance D1 is between 8 millimeters and 20 millimeters.

[0055] Since the indicator rod 8 is linked to the moving electrode 3, the position of the indicator rod 8 is representative of the position of the moving electrode 3. The position of the indicator rod 8 can be easily determined, as at least part of this indicator rod 8 is located outside the insulator 5 and is therefore easily accessible. It is thus possible to easily determine the position of the moving electrode 3. The indicator rod 8 is configured to indicate an overtravel S of the actuating lever 4 relative to the opening distance D1 between the fixed electrode 2 and the moving electrode 3. From this information, it is possible to verify that the amplitude of movement of the actuating lever 4 allows sufficient compression of the compression means 7, and therefore allows the application of sufficient contact pressure between the electrodes 2 and 3 of the vacuum bulb 1.A potential decrease in overtravel S during the product's lifetime can thus be measured. If this contact pressure is insufficient, particularly due to erosion of the electrode contacts 2 and 3 during the use of the switching device 50, an alarm signal may be triggered. Corrective action can also be taken. For example, the switching device may need to be adjusted to restore sufficient overtravel, ensuring adequate contact pressure.

[0056] The indicator rod 8 is configured to indicate a distance between the moving electrode 3 and the insulator 5, this distance is equal to the overtravel S. The distance between the moving electrode 3 and the insulator 5 is measured along the axis of displacement X of the moving electrode 3 of the vacuum bulb 1.

[0057] In the examples shown, the indicator rod 8 is rigidly linked to the moving electrode 3. Rigidly linked means that the relative positioning of the indicator rod 8 and the moving electrode 3 is invariant under mechanical stresses representative of normal use of the cutting device 50. A kinematic link comprising at least one articulation is also conceivable.

[0058] The indicator rod 8 is electrically insulated from the moving electrode 3. In the examples shown, the indicator rod 8 is electrically insulating. The indicator rod 8 is, for example, made of thermoplastic material. The indicator rod 8 can also, for example, be made of epoxy resin or polyester. The insulator 5 extends along a longitudinal axis X, and the indicator rod 8 is parallel to the longitudinal axis X. The diameter of the indicator rod 8 is between 2 and 5 millimeters.

[0059] According to the illustrated embodiments, the cutting device 50 comprises a control sleeve 6 integral with the movable electrode 3, and the compression means 7 exerts a repulsive force between the control sleeve 6 and the insulator 5 so as to press the control sleeve 6 against the insulator 5 when the movable electrode 3 is distant from the fixed electrode 2. More specifically, the compression means 7 exerts a repulsive force between the control sleeve 6 and the insulator 5 so as to press the control sleeve 6 against the stop 16 when the movable electrode 3 is distant from the fixed electrode 2.

[0060] The compression means 7 is an elastic return means. In this example, the compression means 7 is a spring. More precisely, the spring 7 is a helical spring. In the illustrated example, the compression means 7 is a helical spring extending along the longitudinal axis X. According to an alternative (not shown), the compression means could be a stack of Belleville washers, or any other conceivable compression means.

[0061] The insulator 5 has a receiving housing 15 for the control socket 6. The control socket 6 is housed in the receiving housing 15. The receiving housing 15 extends along the longitudinal axis X.

[0062] The compression means 7 exerts a restoring force between the control sleeve 6 and the insulator 5 so as to press the control sleeve 6 against a stop 16 of the receiving housing 15 when the moving electrode 3 is away from the fixed electrode 2. In other words, when the moving electrode 3 does not apply force to the fixed electrode 2, the control sleeve 6 is pushed by the spring 7 against the stop 16. This configuration is illustrated in the figure 1 .

[0063] The stop 16 can be an added component fixed to the insulator 5. The stop 16 has a passage 29 for the control sleeve 6. The stop 16 has a general annular ring shape with a hole in its center. The stop 16 extends transversely to the longitudinal axis X.

[0064] The control sleeve 6 has a shoulder 28 configured to bear against the stop 16. The control sleeve 6 is secured to the moving electrode 3 by a threaded element 26. Other fastening methods are possible for securing the moving electrode 3 and the control sleeve 6. An electrical connection terminal 27 of the electrical circuit 30 is located between the control sleeve 6 and the moving electrode 3. In the example shown in the various figures, the threaded element 26 passes through the electrical connection terminal 27.

[0065] When the electrical circuit 30 is closed, the actuating lever 4 pivots around the Y-axis. The moving electrode 3 thus approaches the fixed electrode 2. Throughout the phase where a distance exists between the moving electrode 3 and the fixed electrode 2, the compression means 7 keeps the control sleeve 6 pressed against the stop 16. Once the lever 4 has moved sufficiently, the moving electrode 3 comes into contact with the fixed electrode. The movement of the lever 4 then continues.

[0066] The degree of compression of the compression means 7 increases progressively as the actuating lever 4 moves from the position in which the fixed electrode 2 contacts the moving electrode 3 to the position corresponding to the maximum stroke of the actuating lever 4. The control sleeve 6 is no longer pressed against the stop 16 and moves away from it along the longitudinal axis X. The remaining travel of the lever 4 compresses the compression means 7. The amplitude of the compression stroke determines the load applied by the compression means 7, and consequently the contact pressure between the fixed electrode 2 and the moving electrode 3 once the actuating lever 4 has reached its maximum travel position P2. The compression means 7 can be in a compressed state relative to its free length when the control sleeve 6 is bearing against the stop 16.This initial preload increases the potential energy stored by the compression variation provided by the overtravel of the actuation lever 4. Preferably, the overtravel S is between 2 and 5 millimeters.

[0067] The control sleeve 6 is away from the stop 16 when the actuating lever 4 is in the closed position P2.

[0068] In the present configuration, the actuating lever 4 is linked to a control plate 11, which is itself linked to the insulator 5. The moving electrode 3 is linked to a control socket 6, and a compression means 7 bears against the insulator 5 and the control socket 6. This configuration minimizes the mass of the moving parts attached to the moving electrode 3. Thus, when the vacuum bulb is opened, the elastic energy stored by the compression means 7 is released to a lower mass than with some solutions chosen by certain manufacturers, which allows for a better impulse to be given to the moving electrode 3. The opening of the electrical circuit 30 is therefore ensured more reliably.

[0069] According to a first embodiment which is not part of the invention, illustrated in the figures 1 to 4 , the indicator rod 8 passes through the insulator 5.

[0070] For this reason, and as detailed in particular on the figure 3 The indicator rod 8 is received in a passage channel 9 of the insulator 5. The passage channel 9 is here coaxial with the insulator 5. The indicator rod 8 is thus, in this first embodiment, coaxial with the insulator 5.

[0071] As detailed on the figure 3The shut-off device 50 may include a sealing ring 10 radially positioned between the indicator rod 8 and the passage channel 9 of the insulator 5. The sealing ring 10 is an O-ring. The O-ring is compressed between the indicator rod 8 and the passage channel 9 of the insulator 5. The compression ratio is greater than or equal to 5%. The compression ratio of the O-ring is defined as the ratio of the difference between the diameter of the O-ring in its free state and the diameter of the O-ring when mounted in the passage channel 9, divided by the diameter of the O-ring in its free state. In other words, the compression ratio of the O-ring is (free diameter - mounted diameter) / free diameter. According to an alternative (not shown), the sealing ring 10 may be a lip seal. The sealing ring 10 is, for example, a four-lobe seal. The sealing gasket 10 improves the electrical insulation between the moving electrode 3 and the end of the rod 8 opposite the moving electrode 3.Indeed, the joint 10 limits the risk of an electric arc traveling along the passage channel 9.

[0072] More specifically, the passage channel 9 comprises a first cylindrical section 17 with a first diameter d1. The channel comprises a second cylindrical section 18 with a second diameter d2, the second diameter d2 of the second cylindrical section 18 being larger than the first diameter d1 of the first cylindrical section 17. The first diameter d1 is between 3 and 8 millimeters. The second diameter d2 is between 5 and 20 millimeters.

[0073] The indicator rod 8 has a radially situated sealing joint 10 between the indicator rod 8 and the second cylindrical part 18. More precisely, and as detailed on the figure 4The switching device 50 comprises two radially positioned sealing gaskets 10, 10' between the indicator rod 8 and the second cylindrical section 18, the two sealing gaskets 10, 10' being axially offset along the indicator rod 8. The presence of two successive gaskets further improves electrical insulation. Alternatively, three or more gaskets can be arranged successively along the axis of the rod 8. Alternatively, a single gasket may be used. The indicator rod 8 comprises a first cylindrical section 19 with a third diameter d3, and a second cylindrical section 20 with a fourth diameter d4, the fourth diameter d4 being larger than the third diameter d3. The second section 20 of the indicator rod 8 forms a shoulder of the rod 8.

[0074] The second cylindrical part 18 of the passage channel 9 opens into the receiving housing 15 of the compression means 7. Thus, an axial end 36 of the passage channel 9 opens into the receiving housing 15. In this first embodiment, the compression means 7 surrounds the second cylindrical part 19 of the passage channel 9.

[0075] The insulator 5 is linked to a control plate 11 having a pivot 12 extending along an axis Y1 transverse to the longitudinal axis X. The actuating lever 4 is linked to the pivot 12 of the control plate 11. The insulator 5 is linked to the control plate 11 by a screw-nut adjustment system 35 configured to adjust the relative position of the insulator 5 with respect to the control plate 11, so as to adjust the opening distance D1 between the moving electrode 3 and the fixed electrode 2 when the actuating lever 4 is in the first position P1. The adjustment system 35 is detailed in the figure 4The indicator rod 8 passes through the screw-nut adjustment system 35. More specifically, the adjustment system 35 allows the contact overtravel S to be adjusted.

[0076] The insulator 5 is positioned between the moving electrode 3 and the adjustment system 35. The adjustment system 35 includes a sleeve 23 with external threads, configured to move within a threaded bore 24 connected to the control plate 11, and a nut 25 configured to lock the sleeve 23 in position. The adjustment system 35 thus allows adjustment of the contact stroke S, and consequently the distance D1 separating the electrodes 2, 3 from the vacuum bulb 1 when the actuating lever 4 is in the open position P1.

[0077] THE figures 5 and 6 illustrate a second embodiment. In this second embodiment of the cutting device 50, according to the present invention, the indicator rod 8 is radially external to the insulator 5.

[0078] The indicator rod 8 may comprise a cylindrical portion 31 and a set of fins 32 extending transversely to the cylindrical portion. The fins 32 are disc-shaped. The fins 32 are staggered along the cylindrical portion 31 of the indicator rod 11. In the illustrated example, the distance between two consecutive fins 32 is constant.

[0079] The indicator rod 8 is connected to the control sleeve 6 by a connecting rod 33. The connecting rod 33 extends along the transverse direction T. The transverse direction T is perpendicular to both the X and Y axes. The connecting rod 33 and the indicator rod 8 can form a single unit. The indicator rod 8 is positioned opposite an external radial surface 37 of the insulator 5. In an embodiment not shown, the indicator rod 8 is connected to the moving electrode 3 by a connecting rod 33.

[0080] The indicator rod 8 passes through a guide plate 13. The guide plate 13 extends transversely to the indicator rod 8. The guide plate 13 is fixed to the control plate 11.

[0081] The guide plate 13 can serve as a visual reference to determine the position of the axial end of the indicator rod 8. Indeed, the length of the portion of the indicator rod 8 protruding from the guide plate 13 is directly measurable by an operator during a visual check.

[0082] According to both embodiments, a portion of the indicator rod 8 is opposite a position sensor 14 rigidly attached to the control plate 11. For certain types of sensors, such as a Hall effect sensor, the indicator rod 8 includes a magnetic target 21. The position sensor 14 can be attached to the control plate 11 by a mounting tab 38. According to an alternative embodiment not shown, the position sensor 14 can be rigidly attached to the insulator 5.

[0083] The magnetic target 21 is located at one axial end 22 of the indicator rod 8. The magnetic target 21 is, for example, a permanent magnet. The position sensor 14 can be a Hall effect sensor. A magnetoresistive sensor can also be used. As shown schematically in part A of the figure 4, an axial end 22 of the indicator rod 8 may be flush with an edge of a passage orifice of the indicator rod 8 when the actuating lever 4 is in the open position P1. Part B of the figure 4 The diagram shows the position of the indicator rod 8 when the actuating lever 4 is in the closed position P2. The difference between these two positions is equal to the overtravel S of the actuating lever 4 relative to the opening distance D1 between the fixed electrode 2 and the moving electrode 3. This difference is also equal to the variation in the compression of the spring 7 during the closing stroke of the actuating lever 4.

[0084] Thus, an electronic control unit (not shown) can measure the position of the indicator rod 8 when the actuating lever 4 is in the open position P1, and also when the actuating lever 4 is in the closed position P2. The difference between the two measured positions is equal to the compression stroke of the spring 7. Calculating the difference between the two positions therefore makes it possible to verify that the contact pressure ensured by the compression of the spring 7 is sufficient. When the measurement is performed by a position acquisition chain of a magnetic target 21 attached to the indicator rod 8, an automatic warning signal can be issued when the value found is below a predetermined threshold. Corrective action can then be taken, such as an adjustment of the adjustment system 35.

Claims

1. Device (50) for switching a medium-voltage electrical circuit (30), comprising: - a vacuum interrupter (1) comprising a fixed electrode (2) and a mobile electrode (3), - an actuating lever (4) linked to the mobile electrode (3), the actuating lever (4) being mobile between a first position, called the opening position (P1), in which the mobile electrode (3) and the fixed electrode (2) are separated by an opening distance (D1), and a second position, called the closing position (P2), in which the mobile electrode (3) and the fixed electrode (2) are in contact so as to allow a current to flow through the electrical circuit (30), the actuating lever (4) moving from the first position (P1) to the second position (P2) defining a travel of displacement (C1), - an insulator (5) linked to the actuating lever (4), - a compression means (7), exerting a repelling force between the mobile electrode (3) and the insulator (5), in which the travel (C1) of the actuating lever (4) is greater than the opening distance (D1), the switching device comprising: - an indicator stem (8) mechanically linked to the mobile electrode (3), which is configured to extend at least partly out of the insulator (5) when the actuating lever (4) is in the closing position (P2), wherein the indicator stem (8) is radially exterior to the insulator (5), characterized in that the indicator stem (8) passes through a guide plate (13).

2. Switching device (50) according to Claim 1, in which the indicator stem (8) is electrically insulating.

3. Switching device (50) according to Claim 1 or 2, comprising a control fitting (6) secured to the mobile electrode (3), in which the compression means (7) exerts a repelling force between the control fitting (6) and the insulator (5) so as to press the control fitting (6) against the insulator (5) when the mobile electrode (3) is separated from the fixed electrode (2).

4. Switching device (50) according to one of the preceding claims, in which the insulator (5) extends along a longitudinal axis (X), and in which the indicator stem (8) is parallel to the longitudinal axis (X).

5. Switching device (50) according to any one of the preceding claims, in which the insulator (5) is linked to a control plate (11) comprising a pivot (12) extending along an axis (Y1) transverse to the longitudinal axis (X), in which the actuating lever (4) is linked to the pivot (12) of the control plate (11), in which the insulator (5) is linked to the control plate (11) by a screw-nut adjustment system (35) configured to adjust the relative position of the insulator (5) with respect to the control plate (11), so as to adjust the opening distance (D1) between the mobile electrode (3) and the fixed electrode (2) when the actuating lever (4) is in the first position (P1), and in which the indicator stem (8) passes through the screw-nut adjustment system.

6. Switching device (50) according to Claim 1, in which the indicator stem (8) comprises a cylindrical portion (31) and a set of fins (32) extending transversally to the cylindrical portion.

7. Switching device (50) according to any one of the preceding claims in combination with Claim 9, in which a portion of the indicator stem (8) faces a position sensor (14) that is rigidly linked to the control plate (11).