SWITCH FOR HIGH DIRECT VOLTAGE

Abstract

SWITCH FOR HIGH DIRECT VOLTAGE One aspect of the invention relates to a switch (1) for high direct voltage, comprising: a first pair (5) of contacts (6, 7); a second pair (8) of contacts (9, 10); a blow-out coil (2), configured to apply a magnetic field (B) to an electric arc established within the first pair (5) of contacts (6, 7), the switch (1) being remarkable in that the blow-out coil (2) is connected in parallel with the second pair (8) of contacts (9, 10). Figure to be published with the abstract: figure 1

Description

Title of the invention: SWITCH FOR HIGH DIRECT VOLTAGE TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of switches for high direct voltage, such as those used in circuit breakers to protect a power supply line in an electrically powered aircraft. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being or will be adopted by various states. In particular, an ambitious standard applies both to new types of aircraft but also to those currently in circulation requiring the implementation of technological solutions in order to make them compliant with current regulations. Civil aviation has been mobilizing for several years now to make a contribution to the fight against climate change.

[0003] Technological research efforts have already made it possible to significantly improve the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental impacts with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work covers new generations of aircraft engines, the lightening of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as essential complements to technological progress, aeronautical biofuels.

[0006] The implementation of electric propulsion equipment requires the development of switching devices that are safe and fast.

[0007] A switch, whether intended to operate under direct or alternating voltage, generally comprises two contacts, one fixed and the other movable. The contact mobile can take at least two distinct positions, one of which, called the "closed position", corresponds to a mechanical and electrical contact between the fixed and mobile contacts so that a current, direct or alternating, can flow. In a position called the "open position", the mobile contact is distant from the fixed contact so that no more current can flow between the two contacts.

[0008] The opening of the switch (i.e. the passage for the movable contact from its closed position to its open position) can induce the formation of an electric arc, preventing the electrical opening of the circuit. It is therefore necessary, to achieve rapid switching, to extinguish the electric arcs quickly.

[0009] In order to overcome this problem, it is known to implement an electric arc extinguishing member. Document EP 3 126 168 A1 discloses for example an arc extinguishing member, called a "deion", connected in parallel with the fixed and moving contacts. A deion comprises a plurality of fins, called "deionization fins" or "separator fins", superimposed on top of each other and separated by insulators. An electric arc can be pushed towards the separator fins to be sectioned into several arcs. Sectioning into several arcs makes it possible to increase the arc voltage and thus extinguish each arc.

[0010] An arc can be pushed towards a deion by means of a magnetic field (generated by the arc itself or by permanent magnets) thanks to the Laplace force which can be exerted on moving charges. In a fixed magnetic field (such as that generated by permanent magnets), the direction of the Laplace force depends on the direction of the current itself. It may therefore be necessary to use two deions, one for each direction of the current. Since deions can be bulky, the use of two deions can pose problems in integrating the switches.

[0011] To overcome this problem, document US 8,513,558 B2 discloses a circuit breaker in which the magnetic field is generated by means of a so-called "electric arc blowing" or simply "blowing" coil. The direction of the current flowing in the blowing coil makes it possible to modify the direction of the magnetic field in which the electric arc is bathed. Thus, by adjusting the direction of the current in the blowing coil according to the direction of the current in the electric arc, it is possible to push the electric arc towards a single deion, regardless of the direction of the current in the electric arc.

[0012] In document US 8,513,558 B2, the blow-out coil is traversed by the current to be interrupted. The advantage of such a solution is that the current in the blow-out coil reverses when the current in the electric arc reverses. The Laplace force, however, depends on the amplitude of the current to which the force is applied (that of the electric arc) and on the amplitude of the current flowing through the blow-out coil (which is also that of the electric arc). Thus, for low currents, the force applied to the electric arc is not sufficient to push the latter towards the deion.

[0013] Documents US 8,513,558 B2 and US 2013 / 0313228 A1 disclose the use of permanent magnets to ensure a minimum magnetic field even for low intensity electric arcs. The use of permanent magnets may prove unsuitable for certain uses of the switches.

[0014] There is therefore a need to provide a switch using only one electric arc extinguishing member and without a permanent magnet. Summary of the invention

[0015] To this end, the invention is the result of technological research aimed at very significantly improving the performance of aircraft and, in this sense, contributes to reducing the environmental impact of aircraft. For this purpose, the invention relates to a switch for high direct voltage, comprising: • a first pair of contacts, comprising: • a first, fixed contact; and • a second contact, movable along a first trajectory, between a so-called “closed” position and a so-called “open” position, the second contact, in its closed position, being in contact with the first contact so that an electric current can flow, the second contact, in its open position, being distant from the first contact so that no current can flow; • an arc-blow coil, configured to apply a magnetic field between the first contact and the second contact in its open position.

[0016] The switch being remarkable in that it comprises a second pair of contacts comprising: • a third, fixed contact; and • a fourth contact, electrically connected to the second contact, movable along a second trajectory, between a so-called “closed” position and a so-called “open” position, the fourth contact, in its closed position, being in contact with the third contact so that an electric current can flow, the fourth contact, in its open position, being distant from the third contact so that no current can flow; the switch being also remarkable in that the arc blowing coil is at least electrically connected in parallel with the second pair of contacts when the fourth contact is in its open position.

[0017] When the second and fourth movable contacts are in their closed positions, a current can flow between the first and third fixed contacts. The com The switch is thus in a state called "closed" or "passing". When the second and fourth moving contactors are in their open positions (and in the absence of electric arcs), no current can flow between the first and third fixed contacts. The switch is therefore in a state called "open" or "blocked".

[0018] When the switch is opened, i.e. when the moving contacts are separated from their fixed contacts, a first electric arc may form within the first pair of contacts and a second electric arc may form within the second pair of contacts. The first electric arc substantially follows a geometric chord of the first trajectory of the second contact. This chord corresponds to the shortest geometric path between the second contact in its closed position and the second contact in its open position. By "substantially following the geometric chord" is meant parallel to the geometric chord with an angle less than or equal to 30°, and preferably parallel to the geometric chord with an angle less than or equal to 20° and, more preferably, parallel to the geometric chord. The second electric arc, similarly, follows the geometric chord of the second trajectory of the fourth contact.The flow of a current in the switch is thus maintained as long as these two arcs are maintained.

[0019] Connecting the blow-out coil in parallel with the second pair of contacts allows the latter to be powered by the voltage of the electric arc. A portion of the electric current, equal to the arc voltage divided by the coil resistance, flowing from the third contact to the fourth contact therefore flows in the blow-out coil. Therefore, the blow-out coil can generate a magnetic field in which the first electric arc is immersed. This results in the application of a Laplace force on the first electric arc, oriented in a third direction, substantially perpendicular to the geometric chord of the first trajectory and perpendicular to the direction of the magnetic field. This Laplace force can be used to push the electric arc in the third direction, for example towards an electric arc extinguishing device such as a deion.

[0020] By "substantially perpendicular" is meant having an angle between 70° and 110° and, preferably, having an angle between 80° and 100° and, more preferably, perpendicular. In the same way, by "substantially parallel" is meant having an angle between -20° and +20° and, preferably, having an angle between -10° and +10° and, more preferably, parallel.

[0021] As soon as the first electric arc is extinguished, no more current can flow within the first pair of contacts having the effect of extinguishing the second electric arc. From then on, no more current flows in the switch which is therefore in the open state.

[0022] The direction of the magnetic field lines generated by the blow-out coil depends on the direction of the current flowing through the blow-out coil. Thus, if the direction of this current changes (in other words, if the direction of the current between the first and third fixed contacts changes), then the magnetic field generated by the blow-out coil also changes direction. This double change of direction (which results in a double change of sign in the Laplace force equation) implies that the Laplace force applied to the first electric arc is independent of the direction of the latter. In other words, it is always applied in the same third direction and in a single direction. Thus, the blow-out coil makes it possible to push the first arc in the third direction (for example, towards a single extinguishing device), regardless of the direction of the current flowing in this first arc.

[0023] The potential difference applied across the blower coil is equal to the potential difference between the third and fourth contacts. When a second electric arc is established between these contacts, the potential difference is equal to the back-electromotive force (also called "arc voltage") of the second electric arc. The arc voltage depends on the materials used to form the contacts and the spacing of the contacts, but it has little dependency on the intensity of the arc current. Therefore, the arc voltage within the second pair of contacts is fixed, regardless of the intensity of the current flowing in the second arc. For a pair of contacts of a high-voltage switch, the arc voltage is, for example, between 15 V and 30 V.Thus, the blower coil, which is polarized by a constant voltage, regardless of the intensity of the arc current, generates a constant magnetic field, regardless of the intensity of the current flowing in the first arc. The Laplace force applied to the first electric arc therefore depends only on the intensity of the current flowing in this first arc. Even when the first electric arc is of low intensity, the Laplace force applied is sufficient to push the said arc, for example towards an extinguishing device. It is therefore no longer necessary to resort to the use of permanent magnets.

[0024] Advantageously, the switch comprises an electric arc extinguishing member electrically connected in parallel with the first pair of contacts, the arc extinguishing member comprising a first end, electrically connected to the first contact and a second end, electrically connected to the second contact.

[0025] According to a development, the arc extinguishing member extends, between its first end and its second end, in a plane parallel to the geometric chord of the first trajectory and parallel to the direction of the magnetic field generated by the blowing coil. In this way, the Laplace force applied to the first electric arc is directed towards the extinguishing device. The blowing coil has preferably a center and the direction of the magnetic field is preferably considered at the center of the blowing coil.

[0026] According to a development, the arc extinguishing member comprises a plurality of conductive fins, parallel to each other, uniformly distributed between the first and second ends of the extinguishing member, maintained at an equal distance from each other and insulated from each other.

[0027] According to a development, the switch comprises a blowing horn comprising: • a first electrical conductor electrically connected to the first contact and extending from the first fixed contact towards the first end of the arc extinguishing device; and • a second electrical conductor electrically connected to the second contact and extending from the second contact toward the second end of the arc extinguishing device.

[0028] Advantageously, the blowing coil is arranged relative to the first pair of contacts so that the generated magnetic field is oriented in a direction substantially perpendicular to a geometric chord of the first trajectory. Since the first electric arc substantially follows the chord of the first trajectory, the Laplace force is maximum at the level of the first electric arc.

[0029] Advantageously, the blowing coil comprises a first plurality of turns extending in a first plane substantially parallel to the geometric chord of the first trajectory, the first plurality of turns having a first center opposite the geometric chord of the first trajectory. In this way, the magnetic field generated by the blowing coil is maximum at the level of the electric arc. The magnetic field also has better homogeneity so as to exert a constant thrust on the first electric arc.

[0030] Advantageously, the blowing coil comprises a second plurality of turns extending in a second plane, parallel to the first plane, the second plurality of turns having a second center opposite the geometric chord of the first trajectory, the first pair of contacts being arranged between the first plurality of turns and the second plurality of turns.

[0031] Advantageously, the arc blowing coil is also electrically connected in parallel with the second pair of contacts when the fourth contact is not in its open position. In other words, the arc blowing coil is electrically connected in parallel with the second pair of contacts.

[0032] Advantageously, the second and fourth contacts are mechanically linked so as to move simultaneously. Thus, when the first pair of contacts opens, the second pair of contacts also opens. An electric arc appears therefore simultaneously within each pair of contacts. The blowing coil, in parallel with the second pair of contacts, can therefore be supplied with an electric current and generate a magnetic field allowing the first electric arc to be pushed.

[0033] The invention also relates to an aircraft propulsion system comprising an electrical power supply line for high direct voltage and a switch according to the invention, the first contact or the third contact of the switch being connected to the electrical power supply line.

[0034] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0035] The figures are presented for information purposes only and in no way limit the invention. Unless otherwise specified, the same element appearing in different figures has a single reference.

[0036] [Fig.l] shows an embodiment of a switch according to the invention.

[0037] [Fig.2] and [Fig.3] show two examples of implementation of the switch of [Fig.l], the switch blow-out coil being hidden. DETAILED DESCRIPTION

[0038] [Fig.l] schematically shows an embodiment of a switch 1 according to the invention. This switch 1 can be implemented in an aircraft propulsion system. Said propulsion system comprises for example an electric motor operating under high direct voltage and an electrical supply line for the electric motor. High direct voltage is understood to mean a direct voltage greater than 800 V. The switch illustrated in [Fig.l] can be connected to the supply line or inserted in series in the supply line. The switch 1 according to the invention thus makes it possible to achieve rapid switching of the electrical voltage of the supply line.

[0039] The switch 1 can have a “closed” or “passing” state, allowing a current to flow in the power supply line. It can also have a so-called “open” or “blocked” state, allowing no current to flow.

[0040] The switch 1 of [Fig.l] comprises an input line 11 and an output line 12, which can be interchanged. One of the input or output lines 11, 12 is for example connected to the high voltage DC power supply line of the propulsion system.

[0041] The switch 1 also comprises two pairs 5, 8 of contacts configured to establish an electrical contact. The first pair 5 of contacts comprises a first contact 6 and a second contact 7. The first and second contacts 6, 7 are electrical conductors configured to cooperate so as to make a mechanical contact and thus establish an electrical contact. The first and second contacts 6, 7 have, for example, on their facing faces, a flat or slightly curved surface so as to make a flat or point mechanical contact.

[0042] The second pair of contacts 8 similarly comprises a third contact 9 and a fourth contact 10. The third and fourth contacts 9, 10 are also electrical conductors configured to cooperate so as to make a mechanical contact and thus establish an electrical contact.

[0043] In [Fig.l], the first contact 6 is fixed and connected to the input line 11 of the switch 1. The third contact 9 is also fixed but is connected to the output line 12. By fixed, it is meant that the movements of the first and third contacts 6, 9 are negligible, or even zero, compared to the other elements of the switch 1 (such as the blowing coil 2, the extinguishing device 16 or the input and output lines 11, 12).

[0044] The second contact 7 is movable relative to the first contact 6. [Fig.l] comprises an orthonormal XYZ reference frame. In [Fig.l], the second contact 7 moves along a first rectilinear trajectory, parallel to the Z axis. It could also move along a first elliptical or circular trajectory, with for example a center of rotation along the X axis or the Y axis. The second contact 7 is movable between two extreme positions corresponding to a so-called "closed" position and a so-called "open" position. In the closed position, the second contact 7 is in mechanical (and therefore electrical) contact with the first contact 6. In the open position, the second contact 7 is distant from the first contact 6. The distance separating the two contacts 6, 7 in the open position is sufficient so that no electric arc is established spontaneously. In [Fig.l], the second contact 7 is in the open position.

[0045] The fourth contact 10 is also movable relative to the third contact 9. In [Fig.l], the fourth contact 10 also moves along a second rectilinear path, parallel to the Z axis. It, in the same way as the second contact 7, moves along an elliptical or circular path, with for example a center of rotation along the X axis or the Y axis. The fourth contact 10 is also movable between a closed position and an open position. In the closed position, the fourth contact 10 is in mechanical contact with the third contact 9. In the open position, the fourth contact 10 is distant from the third contact 9 so that no electric arc is established spontaneously.

[0046] The second and fourth contacts 7, 10 may be linked to each other so as to move simultaneously along their respective trajectories. In [Fig.l], the second and fourth contacts 7, 10 are mounted on a movable support 20. The support mobile 20 moves for example along a rectilinear path, parallel to the Z axis. In this way, it makes it possible to move the second and fourth contacts 7, 10 along their respective rectilinear paths. The mobile support 20 can also move along a circular path around an axis of rotation along the X axis or the Y axis. In this way, the second and fourth contacts 7, 10 also move along circular paths. The mobile support 20 is preferably rigid.

[0047] The second and fourth contacts 7, 10 are electrically connected to each other so that a current can flow from the first pair 5 of contacts to the second pair 8 of contacts and vice versa. Thus, when both pairs 5, 8 of contacts are in their closed positions (i.e. the second and fourth contacts 7, 10 are in their closed position), an electric current can flow from the first contact 6 to the third contact 9, in other words from the input line 11 to the output line 12. The switch 1 is therefore in a conducting state.

[0048] The two contacts 7, 10 can be connected by means of a conductive sheet. The movable support 20 can connect the two contacts 7, 10 to each other. The movable support is for example made of conductive material and the two contacts 7, 10 are electrically connected to the movable support 20, for example by welding onto said support 20.

[0049] The switch 1 also comprises an arc-blowing coil 2 (simply called a "blowing coil"). In this example, it comprises a conductor wound so as to form a plurality of turns 21. The turns 21 extend, in [Fig.l], in a plane parallel to the X and Z axes. The plurality of turns 21 has a common center 22 (the barycenter of the centers of each turn). The orientation of the turns 21 of the coil 2 makes it possible to generate a directed magnetic field, at the level of the common center 22, along the Y axis. The turns 21 of the coil 2 are arranged so that the generated magnetic field B is located between the first contact 6 and the second contact 7 (when the latter is in its open position). Preferably, the common center 22 of the turns 21 is opposite the electric arc established between the first and second contacts 6, 7. In this way, the Laplace force exerted on the electric arc is maximum.In the examples in Figures 2 and 3, the electric arcs are substantially parallel to the Z axis. They therefore undergo a Laplace force oriented along the X axis.

[0050] When the first and second trajectories are rectilinear, as illustrated in [Fig.l], the optimal position of the center 22 of the turns 21 is obvious. However, when the trajectories are not rectilinear, for example when the first trajectory is circular or elliptical, it is preferable for the center 22 of the turns 21 to be opposite the geometric chord of the first trajectory followed by the second contact 7 and between its closed position and its open position. Indeed, the first arc electrical, established between the first and second contacts 6, 7 is more likely to follow the geometric chord of the first trajectory.

[0051] The coil 2 is electrically connected in parallel with the second pair 8 of contacts. In other words, it is connected to the third contact 9 on the one hand and to the fourth contact 10 on the other hand. The coil 2 comprises, for example, two conductors 3, 4 connected to the turns 21. These conductors 3, 4 make it possible to power the coil 2. The first conductor 3 is electrically connected to the fourth contact 10. It is, for example, connected to the mobile support 20 which is electrically connected to the fourth contact 10. The second conductor 4 is electrically connected to the third contact 9. It is, for example, connected to the output line 12 which is electrically connected to the third contact 9.

[0052] In [Fig.l], the turns 21 have a winding in an indirect direction (i.e., a clockwise direction). A current flowing from the first conductor 3 to the second conductor 4 (i.e., from the fourth contact 10 to the third contact 9) then allows the coil 2 to generate a magnetic field along the Y axis and in the direction of increasing Y. Conversely, a current flowing from the second conductor 4 to the first conductor 3 (or a permutation of the first and second conductors 3, 4) then allows the coil 2 to generate a magnetic field in the direction of decreasing Y.

[0053] In [Fig.l], the magnetic field B generated by the coil 2 is oriented perpendicular to the first trajectory of the second contact 7, this first trajectory being rectilinear and along the Z axis. It is advantageous for the magnetic field B to be perpendicular to the electric arc established within the first pair 5 of contacts, so that the Laplace force applied is optimal. The electric arcs tend to follow the shortest electrical path between the first contact 6 and the second contact 7. This electrical path is close to the geometric chord of the first trajectory carried out by the second contact 7 between its closed position and its open position. It is therefore preferable for the magnetic field B generated by the coil 2 to be perpendicular to said geometric chord of the first trajectory.

[0054] In [Fig.l], the coil 2 is continuously connected to the second pair 8 of contacts. When the first and second pairs 5, 8 are open and in the absence of electric arcs, no current flows in the coil 2. The coil 2 therefore only operates when an electric arc is established within the second pair 8 of contacts. When the first and second pairs 5, 8 of contacts are closed, a substantial part of the current flowing in the switch 1 passes through the contacts rather than through the coil 2. To prevent part of the current from passing through the coil 2, it is conceivable that the coil 2 is only connected in parallel with the second pair 8 when the fourth contact 10 is in its open position. The coil 2 can for example be connected to the mobile support 20 in the high position by means of a dry contact.

[0055] The switch 1 preferably comprises an arc extinguishing device 16. In the example of [Fig.l], this is a device called a "deion". The deion 16 makes it possible to extinguish an electric arc which is pushed into the latter by cutting the electric arc into a plurality of arcs of shorter lengths. It comprises a plurality of conductive fins 17 arranged parallel to each other and separated two by two by an electrical insulator. In the example of [Fig.l], each fin 17 extends parallel to the X and Y axes. The fins 17 are uniformly distributed (i.e. at regular intervals) along the Z axis. The deion 16 has a first end 18, corresponding to a first extreme fin, and a second end 19, corresponding to another extreme fin.The first end 18 of the deion 16 is for example electrically connected to the first contact 6 and the second end 19 of the deion 16 is electrically connected to the second contact 7.

[0056] In order for the first electric arc, established within the first pair 5 of contacts, to be effectively extinguished by the extinguishing member, it is advantageous for the latter to be parallel to the arc to be extinguished. The first and second ends 18, 19 of the extinguishing member 16 are therefore advantageously aligned in a plane which is: • parallel to the geometric chord of the first trajectory (chord preferentially followed by the electric arc); and • parallel to the direction of the magnetic field generated by the blowing coil 2.

[0057] The switch 1 may also have a blowing horn 13 intended to guide an electric arc towards the extinguishing device 16. In the example of [Fig.l], the blowing horn 13 is configured to guide an electric arc established in the first pair 5 of contacts towards the deion 16. For this, it comprises a first conductor 14 electrically connected to the first fixed contact 6, and extending towards the first end 18 of the deion 16. Said first conductor 14 may also be in electrical contact with the first end 18 and in particular the first extreme fin of the deion 16. The blowing horn 13 also comprises a second conductor 15 electrically connected to the second contact 7, and extending towards the second end 19 of the deion 16. Said second conductor 15 may also be in electrical contact with the second end 19 and in particular the second extreme fin of the deion 16.The second conductor 15 of the blowing horn is for example integral with the mobile support 20 connecting the second and fourth contacts 7 and 10.

[0058] Figures 2 and 3 schematically show two modes of operation of the switch 1 of [Fig.l]. In these examples, the blowing coil 2 is masked. Only the magnetic field B, generated by coil 2, is represented.

[0059] The opening of the pairs 5, 8 of contacts, that is to say the passage of the second and fourth contacts 7, 10 from their closed positions to their open positions, can create electric arcs. A first electric arc 31 is established for example within the first pair 5 of contacts while a second electric arc 32 is established within the second pair 8 of contacts. The first and second electric arcs 31, 32 are represented by dotted lines within each pair 5, 8 of contacts. In the illustrated examples, the current densities J31, J32 as well as the directions of circulation of the currents in the first and second electric arcs are represented by an arrow. The first and second arcs 31, 32 may deviate from the geometric arcs of the first and second trajectories, however the associated current densities are substantially parallel to these geometric arcs.

[0060] The coil 2 is connected in parallel with the second pair 8 of contacts. A first part of the current flowing between the second and fourth contacts 7, 10 (i.e. in the movable support 20) flows in the second electric arc 32 while a second part of the current flows in the blowing coil 2.

[0061] In [Fig.2], the direction J32 of current flow in the second arc 32 (from the fourth contact 8 to the third contact 7) induces a current flowing in the coil 2 of the first conductor 3 to the second conductor 4. The generated magnetic field B is therefore oriented along the +Y axis. The Laplace force F31 acting on the first electric arc 31 is given by the vector product:

[0062] = JH x B

[0063] The vector product is represented by the symbol “x”.

[0064] The current density is negative because the charges considered are electrons. Laplace force F31 is therefore directed along the X axis, in the direction of increasing X. It is notably directed towards the extinguishing device 16. The blowing coil 2 therefore applies a magnetic field B which induces a Laplace force F31 pushing the first electric arc 31 towards the deion 16.

[0065] In [Fig. 3], the directions of circulation of the currents in the first and second electric arcs 31, 32 are reversed. As a result, the direction of the current flowing in the blowing coil 2 is also reversed. The generated magnetic field B is therefore oriented along the Y axis, in the direction of decreasing Y. However, this double inversion of direction (direction of the current density J31 and direction of the magnetic field B) means that the Laplace force is given by the vector product:

[0066] JH = -jTï X -B = JM XB

[0067] The Laplace force F31 acting on the first electric arc 31 is therefore oriented along the X axis, in the direction of increasing X. The Laplace force F31 therefore pushes the first arc 31 in the same direction and in the same sense, regardless of the direction of flow of the current in the first arc 31. In this case, a single extinguishing device 16 is necessary to extinguish the first arc 31.

Claims

Claims

1. Switch (1) for high direct voltage, comprising: - a first pair (5) of contacts (6, 7), comprising: - a first contact (6), fixed; and - a second contact (7), movable along a first trajectory, between a so-called "closed" position and a so-called "open" position, the second contact (7), in its closed position, being in contact with the first contact (6) so that an electric current can flow, the second contact (7), in its open position, being distant from the first contact (6) so that no current can flow; - an electric arc blowing coil (2), configured to apply a magnetic field (B) between the first contact (6) and the second contact (7) in its open position, the switch (1) being characterized in that it comprises a second pair (8) of contacts (9, 10) comprising: - a third contact (9), fixed; and - a fourth contact (10), electrically connected to the second contact (7), movable along a second trajectory, between a so-called "closed" position and a so-called "open" position, the fourth contact (10), in its closed position, being in contact with the third contact (9) so that an electric current can flow, the fourth contact (10), in its open position, being distant from the third contact (9) so that no current can flow; and in that the arc-blowing coil (2) is at least electrically connected in parallel with the second pair (8) of contacts (9, 10) when the fourth contact (10) is in its open position.

2. Switch (1) according to the preceding claim, comprising an electric arc extinguishing member (16) electrically connected in parallel with the first pair (5) of contacts (6, 7), the arc extinguishing member (16) comprising a first end (18), electrically connected to the first contact (6) and a second end (19), electrically connected to the second contact (7).

3. Switch (1) according to the preceding claim, in which the arc extinguishing member (16) extends, between its first end (18) and its second end (19), in a plane parallel to a geometric chord of the first trajectory and parallel to the direction of the magnetic field (B).

4. Switch (1) according to one of the two preceding claims, in which the arc extinguishing member (16) comprises a plurality of conductive fins (17), parallel to each other, uniformly distributed between the first and second ends (18, 19) of the arc extinguishing member (16), maintained at an equal distance from each other and separated from each other by an electrical insulator.

5. Switch (1) according to one of the three preceding claims, comprising a blowing horn (13) comprising: - a first electrical conductor (14) electrically connected to the first contact (6) and extending from the first contact (6) towards the first end (18) of the arc extinguishing device (16); and - a second electrical conductor (15) electrically connected to the second contact (7) and extending from the second contact (7) towards the second end (19) of the arc extinguishing device (16).

6. Switch (1) according to one of the preceding claims, wherein the blowing coil (2) is arranged relative to the first pair (5) of contacts so that the magnetic field (B) generated is oriented in a direction (Y) substantially perpendicular to a geometric chord of the first trajectory.

7. Switch (1) according to one of the preceding claims, in which the blowing coil (2) comprises a first plurality of turns (21) extending in a first plane substantially parallel to the geometric chord of the first trajectory, the first plurality of turns having a first center (22) opposite the geometric chord of the first trajectory.

8. Switch (1) according to one of the preceding claims, wherein the arc-blowing coil (2) is also electrically connected in parallel with the second pair (8) of contacts (9, 10). when the fourth contact (10) is not in its open position.

9. Switch (1) according to one of the preceding claims, wherein the second and fourth contacts (7, 10) are mechanically linked so as to move simultaneously.

10. An aircraft propulsion system comprising an electrical power supply line for high direct voltage and a switch according to one of the preceding claims, the first contact or the third contact of the switch being connected to the electrical power supply line.

Images