Device for interrupting a medium-voltage electric circuit

Abstract

A cut-off device (50) for a medium-voltage electrical circuit (30) is proposed, comprising: - a vacuum interrupter (1) comprising a movable electrode (3), - an actuating lever (4) connected to the movable electrode (3) and movable between an open position (P1) and a closed position (P2), - an insulator (5) connected to the actuating lever (4), - a control sleeve (6) secured to the movable electrode (3), - an elastic return means (7), exerting a return force between the control sleeve (6) and the insulator (5), in which a displacement stroke (C1) of the actuating lever (4) is greater than the opening distance (D1) such that the control sleeve (6) is moved away from the insulator (5) when the actuating lever (4) is in the closed position (P2), the cut-off device comprising an indicator rod (8) secured to the control sleeve (6),configured to extend at least partly outside the insulator (5) when the actuating lever (4) is in the closed position (P2).,

Description

Technical field

[0001] The present invention relates to the field of medium voltage current cut-off devices, i.e. voltages greater than 1 kV and generally up to 52 kV, and with an intensity of the order of 1000 to 3000 Amperes. The invention relates in particular to cut-off devices in which the current is cut off by opening a vacuum interrupter arranged in series in a main branch of an electrical circuit. Prior art

[0002] The vacuum interrupter 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 the two extreme positions, the control lever is locked and then unlocked depending on the expected action: opening or closing the cut-off device. By operating the control lever, the connecting rod is moved and separates or brings the movable electrode closer to the fixed electrode, which opens or closes the electrical circuit.

[0003] When the circuit is closed, sufficient contact pressure must be guaranteed between the two electrodes of the vacuum interrupter, 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 connection between the control lever and the connecting rod, and the travel of the control lever is greater than the minimum travel required to ensure contact between the electrodes of the vacuum interrupter. The overtravel therefore makes it possible to compress the spring and thus apply a desired minimum contact pressure. This overtravel appears in the connection between the control lever and the control connecting rod. Furthermore, the travel required to obtain contact between the electrodes of the vacuum interrupter changes over time, in particular due to erosion of the contacts and wear of the mechanism as the cut-off device is used. Consequently, the compression of the spring creating the contact pressure also changes, which means that the contact pressure changes over the life of the product.

[0005] In order to be able to alert you to the need to carry out maintenance on the equipment or to replace it, it is important to be able to determine the pressure between the electrodes of the vacuum interrupter throughout the use of the product. The overtravel between the control lever and the control rod is directly correlated to the contact pressure. It is therefore important to be able to monitor this overtravel. For this reason, some manufacturers choose to place the spring between the control lever and the control rod. This arrangement allows easy access and visibility, outside the live area, of the overtravel mentioned, and allows the simple installation of a position sensor to monitor the overtravel in question.

[0006] On the other hand, it is interesting to minimize the mass of the moving parts of the switching device arranged between the contact pressure spring and the moving contact, in order to obtain better circuit opening performance. Some manufacturers then choose to position the spring, allowing the desired contact pressure to be created as close as possible to the moving electrode, at the level of the control rod. The overtravel allowing the spring to be pushed in is then no longer apparent, which no longer allows easy installation of a position sensor.

[0007] The aim of the invention is to provide a solution for minimizing the mass of the moving parts of the device while making it possible to easily monitor the overtravel throughout the use of the cutting device. Summary

[0008] To this end, the invention proposes a device for cutting 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 open position in which the movable electrode and the fixed electrode are separated by an opening distance, and a second position called the closed position in which the movable electrode and the fixed electrode are in contact so as to allow current to flow 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 repulsion force between the mobile electrode and the insulator, in which the stroke of the actuating lever is greater than the opening distance, the cut-off device comprising: an indicator rod mechanically connected to the movable electrode, configured to extend at least partially outside the insulator when the actuating lever is in the closed position.

[0009] Since the indicator rod is connected to the movable electrode, the position of the indicator rod is representative of the position of the movable electrode. The position of the indicator rod is easily determinable, since at least part of this indicator rod is located outside the insulator and is therefore easily accessible. It is thus possible to easily determine the position of the movable electrode. It is thus possible to verify that the displacement amplitude allows the application of sufficient contact pressure between the electrodes of the vacuum interrupter. In the event that this contact pressure is insufficient, due to erosion of the electrode contacts, a warning signal can be triggered. Corrective action can also be taken. For example, an adjustment of the cut-off device can possibly be carried out in order to regain sufficient displacement amplitude of a control socket mechanically connected to the movable electrode.

[0010] 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.

[0011] The indicator rod is configured to indicate overtravel of the actuating lever relative to the opening distance between the fixed electrode and the movable electrode.

[0012] According to one embodiment, the indicator rod is rigidly connected to the movable electrode.

[0013] Preferably, the indicator rod is electrically insulated from the movable electrode.

[0014] According to one embodiment of the cut-off device, the indicator rod is electrically insulating.

[0015] The indicator rod is made of epoxy resin, or polyester.

[0016] According to one embodiment, the cutting device comprises a control sleeve secured to the movable electrode, and the compression means exerts a repulsion force between the control sleeve and the insulator so as to press the control sleeve against the insulator when the movable electrode is distant from the fixed electrode.

[0017] The compression means is an elastic return means. For example, the compression means is a spring. The spring can be a helical spring.

[0018] The mobile electrode is mobile in translation along a longitudinal axis.

[0019] The actuating lever is rotatable about a transverse axis. The transverse axis is perpendicular to the longitudinal axis.

[0020] The insulator has a housing for receiving the control socket.

[0021] The receiving housing extends along the longitudinal axis.

[0022] The compression means exerts a return force between the control sleeve and the insulator so as to press the control sleeve against a stop of the receiving housing when the movable electrode is distant from the fixed electrode.

[0023] The compression means is a helical spring extending along the longitudinal axis.

[0024] The stop has a hole for the control sleeve to pass through.

[0025] The stop extends transversely to the longitudinal axis.

[0026] The control bushing has a shoulder configured to bear against the stop.

[0027] According to one embodiment of the cut-off device, the insulator extends along a longitudinal axis, and the indicator rod is parallel to the longitudinal axis.

[0028] According to an example of implementation of the cut-off device, the indicator rod passes through the insulator.

[0029] For example, the indicator rod is received in a passage channel of the insulator.

[0030] The indicator rod is coaxial with the insulator.

[0031] The cut-off device may include a seal radially between the indicator rod and the passage channel of the insulator.

[0032] The seal can be an O-ring.

[0033] The O-ring is compressed between the indicator rod and the insulator passage channel. A compression ratio is greater than or equal to 5%.

[0034] The seal can be a lip seal. The seal is, for example, a quadrilobe seal.

[0035] The passage channel is coaxial with the insulator.

[0036] The passage channel comprises a first cylindrical portion of a first diameter. The channel comprises a second cylindrical portion of a second diameter, the second diameter of the second cylindrical portion being greater than the first diameter of the first cylindrical portion.

[0037] The indicator rod has a seal radially located between the indicator rod and the second cylindrical part.

[0038] According to an exemplary implementation, the cut-off device comprises two sealing gaskets radially between the indicator rod and the second cylindrical part, the two sealing gaskets being axially offset along the indicator rod.

[0039] The indicator rod has a first cylindrical portion of a third diameter, and a second cylindrical portion of a fourth diameter, the fourth diameter being greater than the third diameter.

[0040] The second cylindrical part of the passage channel opens into the housing for receiving the compression means.

[0041] The compression means surrounds the second cylindrical part of the passage channel.

[0042] According to one embodiment of the cut-off 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 connected to the pivot of the control plate, the insulator is connected 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 movable 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.

[0043] The insulator is arranged between the moving electrode and the adjustment system.

[0044] According to one embodiment of the cut-off device, the indicator rod is radially external to the insulator.

[0045] The indicator rod may include a cylindrical portion and a set of fins extending transversely to the cylindrical portion.

[0046] The fins are disc-shaped.

[0047] The vanes are offset along the cylindrical portion of the indicator rod.

[0048] The distance between two consecutive fins is constant.

[0049] The indicator rod is connected to the control socket by a connecting rod.

[0050] The connecting bar extends in the transverse direction.

[0051] For example, the connecting rod and the indicator rod form a single unit.

[0052] According to one embodiment of the cut-off device, the indicator rod passes through a guide plate.

[0053] The guide plate extends transversely to the indicator rod.

[0054] The guide plate is attached to the control board.

[0055] According to one type of implementation, a portion of the indicator rod is opposite a position sensor rigidly connected to the control board.

[0056] The indicator rod has a magnetic target.

[0057] The magnetic target is arranged at one axial end of the indicator rod.

[0058] The magnetic target is a permanent magnet.

[0059] The position sensor is a Hall effect sensor.

[0060] An axial end of the indicator rod is flush with an edge of a passage hole in the indicator rod when the actuating lever is in the open position. Brief description of the drawings

[0061] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: [ Fig. 1 ] is a sectional view of a cutting device according to a first embodiment of the invention, [ Fig. 2 ] is another sectional view of the cutting device of the figure 1 , [ Fig. 3 ] is a partial sectional view of the cutting device of the figure 1 , [ Fig. 4 ] is another partial view, in section, of the cutting device of the figure 1 , [ Fig. 5 ] is a sectional view of a cutting device according to a second embodiment of the invention, [ Fig. 6 ] is a partial 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 embodiments:

[0062] To facilitate reading the figures, the different elements are not necessarily represented to scale. In these figures, identical elements bear the same references. Certain elements or parameters may be indexed, i.e. designated for example by first element or second element, or first parameter and second parameter, etc. This indexing is intended to differentiate similar, but not identical, elements or parameters. This indexing does not imply a priority of one element or parameter over another and the names may be interchanged. When it is specified that a subsystem includes a given element, this does not exclude the presence of other elements in this subsystem. Similarly, when it is specified that a subsystem includes a given element, it is understood that the subsystem includes at least this element.

[0063] It has been represented on the figure 1a cut-off device 50 of a medium voltage electrical circuit 30, i.e. from 1 to 52 kV. The cut-off device 50 comprises a vacuum interrupter 1 arranged in series in an electrical circuit 30.

[0064] The vacuum bulb 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 comprises a disc-shaped portion extending transversely to the longitudinal axis X. The disc-shaped portion of the movable electrode 3 may be in contact with the disc-shaped portion of the fixed electrode 2, so as to allow a passage of electric current between the electrodes, and therefore in the vacuum bulb 1. The movable electrode 3 is movable in translation along the longitudinal axis X.

[0065] An actuating lever 4 makes it possible to control the opening or closing of the vacuum bulb 1, and thus of the electrical circuit 30. The actuating lever 4 is movable in rotation around a transverse axis Y. The transverse axis Y is perpendicular to the longitudinal axis X.

[0066] A control plate 11 comprises 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 secured to 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 device.

[0067] The present invention proposes a device 50 for cutting off 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 passage 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 repulsion force between the mobile electrode 3 and the insulator 5, in which the stroke C1 of the actuating lever 4 is greater than the opening distance D1, the cut-off device comprising: an indicator rod 8 mechanically linked to the movable electrode 3, configured to extend at least partly outside the insulator 5 when the actuating lever 4 is in the closed position P2.

[0068] The difference between the stroke C1 of the actuating lever 4 and the opening distance D1 is called the overtravel. This overtravel allows there to be a contact pressure between the fixed electrode 2 and the movable electrode 3. The stroke C1 of the actuating lever 4 is greater than the opening distance D1 such that the movable electrode 3 is distant from the insulator 5 when the actuating lever 4 is in the closed position P2. The term "distant" is understood to mean that the distance along the X axis between the movable 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.

[0069] 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 1corresponds to the opening position P1 of the actuating lever 4, and the figure 2corresponds to the closing position P2. The amplitude of the movement of the actuating lever 4 has been exaggerated in order 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 in a housing 34 of the actuating lever 4. The control bar thus passes through each of the arms 40a, 40b of the actuating lever 4. The amplitude of movement C1 of the lever 4 is determined by the construction of the mechanism of the control bar. This amplitude of movement C1 is fixed. The amplitude of movement C1 of the actuating lever 4 is chosen to be greater than the stroke necessary to bring the movable electrode 3 closer to the fixed electrode 2. Thus, the passage of the actuating lever 4 from the opening position P1 to the closing position P2 makes it possible to compress the compression means 7.Other types of kinematic connections 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.

[0070] The indicator rod 8 being connected to the movable electrode 3, the position of the indicator rod 8 is representative of the position of the movable electrode 3. The position of the indicator rod 8 can be easily determined, since at least a 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 movable electrode 3. The indicator rod 8 is configured to indicate an overtravel S of the actuating lever 4 with respect to the opening distance D1 between the fixed electrode 2 and the movable 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, 3 of the vacuum interrupter 1.A possible reduction in overtravel S during the life of the product is thus measurable. In the event that this contact pressure is insufficient, in particular due to erosion of the contacts of the electrodes 2, 3 during use of the cut-off device 50, a warning signal can be triggered. Corrective action can also be taken. For example, an adjustment of the cut-off device can possibly be carried out in order to regain sufficient overtravel, allowing adequate contact pressure.

[0071] The indicator rod 8 is configured to indicate a distance between the movable electrode 3 and the insulator 5, this distance is equal to the overtravel S. The distance between the movable electrode 3 and the insulator 5 is measured along the displacement axis X of the movable electrode 3 of the vacuum bulb 1.

[0072] In the examples shown, the indicator rod 8 is rigidly connected to the movable electrode 3. By rigidly connected is meant that the relative positioning of the indicator rod 8 and the movable electrode 3 is invariant, under mechanical constraints representative of normal use of the cut-off device 50. A kinematic connection comprising at least one articulation is also conceivable.

[0073] The indicator rod 8 is electrically insulated from the movable 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 may, for example, also 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.

[0074] According to the illustrated embodiments, the cut-off device 50 comprises a control sleeve 6 secured to the movable electrode 3, and the compression means 7 exerts a repulsion 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 precisely, the compression means 7 exerts a repulsion 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.

[0075] The compression means 7 is an elastic return means. The compression means 7 is here a spring. More precisely, the spring 7 is here a helical spring. The compression means 7 is in the example illustrated a helical spring extending along the longitudinal axis X. According to a variant not shown, the compression means can be a stack of Belleville washers, or any other conceivable compression means.

[0076] The insulator 5 comprises 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.

[0077] The compression means 7 exerts a return 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 movable electrode 3 is distant from the fixed electrode 2. In other words, when the movable electrode 3 does not apply a 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 FIG. figure 1 .

[0078] The stop 16 may be an added part and fixed to the insulator 5. The stop 16 has a passage orifice 29 for the control sleeve 6. The stop 16 has the general shape of an annular crown having an orifice in its center. The stop 16 extends transversely to the longitudinal axis X.

[0079] The control socket 6 comprises a shoulder 28 configured to bear against the stop 16. The control socket 6 is secured to the movable electrode 3 by a threaded element 26. Other fixing means are possible for securing the movable electrode 3 and the control socket 6. An electrical connection terminal 27 of the electrical circuit 30 is arranged between the control socket 6 and the movable electrode 3. In the example shown in the various figures, the threaded element 26 passes through the electrical connection terminal 27.

[0080] When the electrical circuit 30 is closed, the actuating lever 4 pivots around the Y axis. The movable electrode 3 therefore approaches the fixed electrode 2. During the entire phase where a distance is present between the movable 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 movable electrode 3 comes into contact with the fixed electrode. The movement of the lever 4 continues.

[0081] The degree of compression of the compression means 7 increases progressively when the actuating lever 4 moves from the position in which the fixed electrode 2 comes into contact with the movable electrode 3 to the position corresponding to the maximum stroke of the actuating lever 4. The control sleeve 6 ceases to be pressed against the stop 16 and moves away from it in the direction of the longitudinal axis X. The remainder of the movement stroke 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 existing between the fixed electrode 2 and the movable electrode 3 once the actuating lever 4 has reached its maximum displacement position P2. The compression means 7 may be in a compressed state relative to its free length when the control sleeve 6 is resting on the stop 16.This initial preload makes it possible to increase the potential energy stored by the compression variation ensured by the overtravel of the actuating lever 4. Preferably, the overtravel S is between 2 and 5 millimeters.

[0082] The control sleeve 6 is moved away from the stop 16 when the actuating lever 4 is in the closed position P2.

[0083] In the present configuration, the actuating lever 4 is connected to a control plate 11, itself connected to the insulator 5. The movable electrode 3 is connected to a control socket 6, and a compression means 7 rests on the insulator 5 and on the control socket 6. This configuration makes it possible to minimize the mass of the moving parts secured to the movable electrode 3. Thus, when the vacuum bulb is opened, the elastic energy stored by the compression means 7 is restored at a lower mass than according to certain solutions chosen by certain manufacturers, which makes it possible to give a better impulse to the movable electrode 3. The opening of the electrical circuit 30 is thus ensured more reliably.

[0084] According to a first embodiment, illustrated in the figures 1 to 4 , the indicator rod 8 passes through the insulator 5.

[0085] For this, 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.

[0086] As detailed on the figure 3, the cut-off device 50 may comprise a seal 10 radially between the indicator rod 8 and the passage channel 9 of the insulator 5. The seal 10 is here an O-ring. The O-ring is compressed between the indicator rod 8 and the passage channel 9 of the insulator 5. A compression ratio is greater than or equal to 5%. By compression ratio of the seal, we mean the quotient of the difference between the diameter of the seal in the free state and the diameter of the seal in the state mounted in the passage channel 9, and the diameter of the seal in the free state. In other words, the compression ratio of the seal is the quantity (free diameter - mounted diameter) / free diameter. According to a variant not shown, the seal 10 may be a lip seal. The seal 10 is for example a quadrilobe seal. The seal 10 improves the electrical insulation between the moving electrode 3 and the end of the rod 8 opposite the moving electrode 3.In fact, the seal 10 limits the risk of an electric arc traveling along the passage channel 9.

[0087] More specifically, the passage channel 9 comprises a first cylindrical part 17 with a first diameter d1. The channel comprises a second cylindrical part 18 with a second diameter d2, the second diameter d2 of the second cylindrical part 18 being greater than the first diameter d1 of the first cylindrical part 17. The first diameter d1 is between 3 and 8 millimeters. The second diameter d2 is between 5 and 20 millimeters.

[0088] The indicator rod 8 comprises a seal 10 radially between the indicator rod 8 and the second cylindrical part 18. More precisely, and as detailed in the figure 4, the cut-off device 50 comprises two seals 10, 10' radially between the indicator rod 8 and the second cylindrical part 18, the two seals 10, 10' being axially offset along the indicator rod 8. The presence of two successive seals makes it possible to further improve the electrical insulation. Alternatively, three or more seals may be arranged successively along the axis along the rod 8. As a further variant, it is possible to have a single seal. The indicator rod 8 comprises a first cylindrical part 19 with a third diameter d3, and a second cylindrical part 20 with a fourth diameter d4, the fourth diameter d4 being greater than the third diameter d3. The second part 20 of the indicator rod 8 forms a shoulder of the rod 8.

[0089] 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.

[0090] The insulator 5 is connected to a control plate 11 comprising 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, the insulator 5 is connected 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 movable electrode 3 and the fixed electrode 2 when the actuating lever 4 is in the first position P1. The adjustment system 35 is detailed on the figure 4. The indicator rod 8 passes through the screw-nut adjustment system 35. More precisely, the adjustment system 35 makes it possible to adjust the contact overtravel S.

[0091] The insulator 5 is arranged between the movable electrode 3 and the adjustment system 35. The adjustment system 35 comprises a sheath 23 tapped externally and configured to be moved in a threaded bore 24 connected to the control plate 11, and comprises a nut 25 configured to lock the sheath 23 in position. The adjustment system 35 thus makes it possible to adjust the contact overtravel S, and beyond the distance D1 separating the electrodes 2, 3 from the vacuum interrupter 1 when the actuating lever 4 is in the open position P1.

[0092] THE Figures 5 and 6 illustrate a second embodiment. In this second embodiment of the cut-off device 50, the indicator rod 8 is radially external to the insulator 5.

[0093] 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 have a disc shape. The fins 32 are offset along the cylindrical portion 31 of the indicator rod 11. In the example illustrated, the distance between two consecutive fins 32 is constant.

[0094] The indicator rod 8 is here connected to the control socket 6 by a connecting bar 33. The connecting bar 33 extends in the transverse direction T. The transverse direction T is here perpendicular to the X axis as well as to the Y axis. The connecting bar 33 and the indicator rod 8 can form a single-piece assembly. The indicator rod 8 is opposite an outer radial surface 37 of the insulator 5. According to an embodiment not shown, the indicator rod 8 is connected to the movable electrode 3 by a connecting bar 33.

[0095] 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 board 11.

[0096] The guide plate 13 can serve as a visual reference for determining the position of the axial end of the indicator rod 8. In fact, the length of the portion of the indicator rod 8 extending beyond the guide plate 13 can be directly measured by an operator during a visual inspection.

[0097] According to both embodiments, a portion of the indicator rod 8 is opposite a position sensor 14 rigidly connected to the control board 11. For certain types of sensor, such as a Hall effect sensor, the indicator rod 8 comprises a magnetic target 21. The position sensor 14 can be fixed to the control board 11 by a fixing lug 38. According to an alternative embodiment not shown, the position sensor 14 can be rigidly connected to the insulator 5.

[0098] The magnetic target 21 is arranged at an 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 effect sensor can also be used. As shown diagrammatically in part A of the figure 4, an axial end 22 of the indicator rod 8 can 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 schematizes 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 movable 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.

[0099] 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 carried out by a chain for acquiring the position of a magnetic target 21 secured to the indicator rod 8, an automatic alert signal can be emitted when the value found is below a predetermined threshold. A corrective action can thus be carried out, such as for example an adjustment of the adjustment system 35.

Claims

1. A device (50) for cutting off a medium-voltage electrical circuit (30), comprising: - a vacuum interrupter (1) comprising a fixed electrode (2) and a movable electrode (3), - an actuating lever (4) connected 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 passage of the actuating lever (4) from the first position (P1) to the second position (P2) defining a displacement stroke (C1), - an insulator (5) connected to the actuating lever (4), - a compression means (7), exerting a repulsion force between the moving electrode (3) and the insulator (5),in which the stroke (C1) of the actuating lever (4) is greater than the opening distance (D1), the cut-off device comprising: - an indicator rod (8) mechanically linked to the movable electrode (3), configured to extend at least partly outside the insulator (5) when the actuating lever (4) is in the closed position (P2)., 2. A cut-off device (50) according to claim 1, wherein the indicator rod (8) is electrically insulating.

3. Cutting device (50) according to claim 1 or 2, comprising a control sleeve (6) integral with the movable electrode (3), in which the compression means (7) exerts a repulsion 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).

4. Cut-off 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 rod (8) is parallel to the longitudinal axis (X).

5. Cut-off device (50) according to one of claims 1 to 4, in which the indicator rod (8) passes through the insulator (5).

6. Cut-off device (50) according to the preceding claim, in which the indicator rod (8) is received in a passage channel (9) of the insulator (5).

7. Cut-off device (50) according to the preceding claim, comprising a seal (10) radially between the indicator rod (8) and the passage channel (9) of the insulator (5).

8. Cutting device (50) according to claim 6 or 7, in which the passage channel (9) comprises a first cylindrical part (17) of diameter (d1), and a second cylindrical part (18) of diameter (d2), the diameter (d2) of the second cylindrical part 18 being greater than the diameter (d1) of the first cylindrical part 17, the cutting device (50) comprising two seals (10, 10') radially between the indicator rod (8) and the second cylindrical part (18), the two seals (10, 10') being axially offset along the indicator rod (8).

9. Cut-off device (50) according to one of the preceding claims, wherein the insulator (5) is connected to a control plate (11) comprising a pivot (12) extending along an axis (Y1) transverse to the longitudinal axis (X), wherein the actuating lever (4) is connected to the pivot (12) of the control plate (11), wherein the insulator (5) is connected 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 movable electrode (3) and the fixed electrode (2) when the actuating lever (4) is in the first position (P1), and wherein the indicator rod (8) passes through the screw-nut adjustment system.

10. Cut-off device (50) according to one of claims 1 to 4, in which the indicator rod (8) is radially external to the insulator (5).

11. Cutting device (50) according to the preceding claim, in which the indicator rod (8) comprises a cylindrical portion (31) and a set of fins (32) extending transversely to the cylindrical portion.

12. A cut-off device (50) according to claim 10 or 11, wherein the indicator rod (8) passes through a guide plate (13).

13. Cutting device (50) according to one of the preceding claims in combination with claim 9, in which a portion of the indicator rod (8) is opposite a position sensor (14) rigidly connected to the control plate (11).

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