EP3459100B1 - Breaker device intended to be linked to an electrical circuit - Google Patents

Description

Invention background

The invention relates to a device for interrupting the current flowing in an electrical circuit and to a secure electrical system comprising such a device.

The protection of electrical circuits can currently be ensured by positioning fuses on each of the phases. These fuses make it possible to cut the current in the event of the appearance of a high current for a sufficient duration, their use is reliable in the event of frank failures with high fault currents. However, for currents slightly higher than their nominal current, these fuses can have a relatively long cut-off time or even an incomplete cut. An incomplete cut or made too late can lead to unacceptable damage to the electrical system and in particular to an electrical device supplied by the electrical circuit. It is therefore desirable to improve the quality of the shutdown performed when a malfunction occurs in order to improve the safety and service life of electrical systems.

We know DE 20 2015 106 793 U1 discloses a cut-off device for disconnecting a conductive portion.

There is therefore a need to provide relatively simple shutdown devices to improve the quality of electrical shutdown.

Subject and summary of the invention

To this end, the invention proposes, according to a first aspect, a cut-off device according to claim 1
When activated, the pyrotechnic initiator is configured to produce pressurizing gas to pressurize the pressurizing chamber. The pressurizing gas exerts pressure on the movable cut-off element in order to set it in motion. The movable cut-off element thus set in motion is configured to passing the device into the second configuration in which the conductive portion is disconnected, that is to say in a configuration in which the circulation of an electric current in the conductive portion is interrupted. Thus, when the device is in the second configuration, the electric current flowing in the electric circuit is cut.

The invention provides a cut-off device enabling rapid reliable electrical cut-off in a circuit in the event of an overcurrent of the electric current and thus preventing damage to an electric device supplied by said circuit. More precisely, during normal operation of the system, the fuse element is on, the voltage across the terminals of the relatively low fuse element and the current passing through the ignition device of the pyrotechnic initiator is sufficiently low so as not to activate the latter. On the other hand, when the intensity of the current passing through the fusible element exceeds the predetermined value, the fusible element is triggered, that is to say that its resistance increases so as to initiate the disconnection of the conductive portion. Thus, the voltage at the terminals of the fuse element increases when it trips and therefore the intensity in the ignition device increases, thus enabling the pyrotechnic initiator to be actuated and the device to be switched from the first to the second configuration. in order to permanently cut off the flow of current in the circuit. Another advantage of the invention is that a compact and integrated breaking solution is proposed insofar as the fusible element making it possible to trigger the initiator is present inside the breaking device and not at the outside of the latter. The invention thus advantageously makes it possible to simplify the existing breaking systems by proposing an autonomous breaking device directly integrating the element which will trigger the breaking, in this case the fusible element. This advantageously makes it possible to dispense with the presence of a third-party voltage / current sensor / analyzer device to allow the initiation of the initiator. Thus, the combination of switching off by the fusible element and switching off by setting in motion the movable switching element makes it possible to very significantly improve the safety of supply systems in a relatively simple manner insofar as it makes it possible to independently carry out a complete shutdown and thus avoid situations where the fuse element does not completely cut off the current.

Advantageously, at least one resistor or one diode may be present in series on the line connecting the ignition device of the initiator to one of the terminals of the fuse element.

Such an embodiment advantageously makes it possible to avoid any risk of degradation of the ignition device by the current flowing in the latter.

In an exemplary embodiment, the fusible element can be attached to the conductive portion. In this case, the fusible element constitutes a separate element from the conductive portion which has been connected in series to the latter, for example by welding.

The pressurization chamber constitutes a first chamber of the cut-off device, at least part of the conductive portion being present in a second chamber present in the body, the movable cut-off element separating the first chamber from the second chamber and having at least one relief formed from an electrically insulating material, said at least one relief facing the conductive portion, the movable cut-off element being set in motion towards the conductive portion in order to break it by impact with the relief when switching from the first to the second configuration.

The conductive portion is disconnected by breaking it by impact with the relief when the device passes from the first to the second configuration.

The patent also describes the case where the conductive portion has a first electrically conductive element and a second electrically conductive element and the movable breaking element has a third electrically conductive element, the third conductive element making the electrical connection between the first and second conductive elements when the breaking device is in the first configuration and the third conductive element being released from at least one of the first and second conductive elements so as to prevent the flow of current electric between them when the device is in the second configuration.

In this case, an electric current can flow between the first conductor and the second conductor via the third conductor when the device is in the first configuration. On the other hand, when the device is in the second configuration, the first and the second conductors are no longer electrically connected without the conductive portion being broken. This electrical disconnection results from the displacement of a conductive element of the movable breaking element when the device passes from the first configuration to the second configuration. Thus, in this case, the conductive portion is disconnected by eliminating the electrical connection between at least two conductive elements thereof, without there being any rupture of said conductive portion, following the displacement of the movable cut-off element when the device goes from the first to the second configuration. As will be detailed below, the movable breaking element may, in this case, be entirely formed of an electrically conductive material or comprise the third conductive element and an insulating portion of electricity.

In an exemplary embodiment, the device can comprise a single conductive portion. In this case, the cut-off device can be intended to be connected to a single-phase supply circuit.

Alternatively, the device may include several conductive portions, a fusible element being connected in series to each of the conductive portions, the initiator being able to be connected to the terminals of the fusible element and the fusible element being able to be configured to trip when the intensity of the current flowing through it exceeds the predetermined value and thereby actuate the initiator. In this case, the cut-off device can be intended to be connected to a polyphase supply circuit. The polyphase supply circuit can for example be a three-phase circuit or alternatively have two or at least four phases. By “circuit phase” is meant, unless otherwise stated, the electrical conductor corresponding to said phase of the electrical circuit.

When there are several conductive portions, all the conductive portions are simultaneously electrically disconnected when the device changes from the first to the second configuration. This advantageously allows a complete and simultaneous cut of the current flowing in the circuit.

The invention also relates to a secure electrical system according to claim 5.

In an exemplary embodiment, the electrical system may further comprise an electrical device control element configured to actuate the initiator when the value of an operating parameter of the electrical device reaches a predetermined value.

This embodiment is advantageous in order to achieve a complete cut of the circuit when a malfunction occurs in the electrical device to be supplied and no longer necessarily in terms of overcurrent of the current flowing in the circuit.

The operating parameter can be pressure or temperature. Thus, the control element of the electrical device can be configured to actuate the pyrotechnic initiator when the temperature of the electrical device or the pressure of at least part of the electrical device exceeds a predetermined value.

The present invention also relates to a vehicle comprising at least one secure electrical system as described above. The vehicle can for example be an aircraft, a train or an automobile.

The present invention also relates to an installation comprising at least one secure electrical system as described above.

The electrical device can for example be a train engine. Alternatively, the electrical device can be a heat pump or a power installation.

Brief description of the drawings

• la figure 1 représente une section d'un premier exemple de dispositif de coupure selon l'invention dans la première configuration,
• la figure 2 est une vue éclatée montrant différents éléments constitutifs du dispositif de la figure 1,
• la figure 3 est une vue en perspective du dispositif de coupure de la figure 1 prêt à être relié à un circuit électrique,
• les figures 4A à 4C illustrent la coupure du courant réalisée par le dispositif de la figure 1, et
• la figure 5 est un détail d'un deuxième exemple de dispositif de coupure selon l'invention,
• la figure 5A est un détail d'un troisième exemple de dispositif de coupure (hors invention),
• la figure 6 représente une section d'un quatrième exemple de dispositif de coupure selon l'invention dans la première configuration,
• la figure 7A représente une section d'un cinquième exemple de dispositif de coupure (hors invention) dans la première configuration,
• la figure 7B représente une section du dispositif de coupure de la figure 7A dans la deuxième configuration,
• la figure 8 représente une vue éclatée montrant différents éléments constitutifs du dispositif illustré aux figures 7A et 7B,
• la figure 9 représente de manière schématique un exemple de système électrique sécurisé selon l'invention, et
• la figure 10 représente de manière schématique une variante de système électrique sécurisé selon l'invention.

Other characteristics and advantages of the invention will emerge from the following description of particular embodiments of the invention, given by way of nonlimiting examples, with reference to the appended drawings, in which:

• the figure 1 represents a section of a first example of a breaking device according to the invention in the first configuration,
• the figure 2 is an exploded view showing different components of the device of the figure 1 ,
• the figure 3 is a perspective view of the cut-off device of the figure 1 ready to be connected to an electrical circuit,
• the Figures 4A to 4C illustrate the power cut made by the device of the figure 1 , and
• the figure 5 is a detail of a second example of a breaking device according to the invention,
• the figure 5A is a detail of a third example of a cut-off device (outside the invention),
• the figure 6 represents a section of a fourth example of a breaking device according to the invention in the first configuration,
• the figure 7A represents a section of a fifth example of a cut-off device (outside the invention) in the first configuration,
• the figure 7B represents a section of the cut-off device of the figure 7A in the second configuration,
• the figure 8 shows an exploded view showing different components of the device illustrated in Figures 7A and 7B ,
• the figure 9 schematically represents an example of a secure electrical system according to the invention, and
• the figure 10 shows schematically a variant of a secure electrical system according to the invention.

Detailed description of embodiments

The figure 1 is a sectional view of an exemplary switching device 1 according to the invention. As will be detailed below, there is, in the example of switching device 1 illustrated in the figure 1 , rupture of the conductive portion during the passage of the device 1 from the first to the second configuration. Other arrangements will be described below.

To the figure 1 , the device 1 is in the first configuration, that is to say in a configuration in which an electric current (arrow I) can flow in phase 10 of the supply circuit and in the conductive portion 8. In the example illustrated, the supply circuit is single-phase and the cut-off device 1 comprises a single conductive portion 8. It is not, however, outside the scope of the invention when the circuit comprises a plurality of phases and the cut-off device a plurality of portions conductive, such an exemplary embodiment being discussed below.

The breaking device 1 comprises a pyrotechnic initiator 3 comprising an ignition device 9 provided with two electrical conductors 5 (only one of these conductors being shown on the figure 1 , the two conductors 5 being visible on the figures 2 and 3 ). The pyrotechnic initiator 3 also comprises a pyrotechnic charge 4. The pyrotechnic charge 4 can be in the form of one or more monolithic blocks. Alternatively, the load 4 can be in granular form. It goes from the general knowledge of a person skilled in the art to choose the nature and the dimensions of the pyrotechnic charge to be used for the intended current cut-off application.

The device 1 comprises a body 11 inside which a first 7 and a second 12 chambers are present. The body 11 can for example be formed from a thermoplastic or thermosetting material. The pyrotechnic initiator 3 comprises a seal 6 made of elastically deformable material bearing on an internal wall 14 of the body 11. The ignition device 9 is, in the example illustrated, housed in the body 11. The body 11 further has two through channels 11a, each of the conductors 5 extending in a separate channel 11a. The first chamber 7 constitutes a pressurization chamber and is in communication with an outlet S of the pyrotechnic initiator 3. The pyrotechnic initiator 3 is configured to pressurize the first chamber 7 when it is actuated. In the example illustrated, the pyrotechnic charge 4 is present in the first chamber 7. It is not, however, outside the scope of the invention when this charge is present outside the first chamber as long as the latter remains in communication with an output from the pyrotechnic initiator.

An electrically conductive portion 8 is present in the second chamber 12 (see Figures 1 and 3 especially). The ends of the conductive portion 8 protrude from the body 11 in the example illustrated. This conductive portion 8 is, in the example illustrated, in the form of a tab. The conductive portion 8 can for example be made of copper.

The conductive portion 8 is provided with a fuse 40 which is connected in series to the latter. The fuse element 40 constitutes, in this example, a separate element from the conductive portion 8 which has been attached to it. The fuse 40 can for example be welded or clipped to the conductive portion 8. In the example illustrated, the fuse 40 has been welded with its insulating envelope to the conductive portion 8. The fuse 40 here comprises a fusible core present in an insulating envelope for electricity. The insulating envelope may contain a powder of an electrically insulating material, such as silica, inside which the fusible core is present. The fact of using a fusible core with its insulating envelope advantageously makes it possible to improve the resistance over time of the fusible core, and thus to further improve the reliability of the breaking device. Furthermore, in this example, the fuse 40 is present in the second chamber 12 which is present inside the body 11.

The electrical conductors 5 are each connected to a separate terminal of the fuse 40. More specifically, the side wall 22 of the body 11 has channels 23a and 23b through which electrical conductors 24a and 24b extend. The first electrical conductor 24a connects a first terminal of the fuse 40 to a first conductor 5 of the ignition device 9. The second electrical conductor 24b connects a second terminal of the fuse 40, different from the first, to a second conductor 5 of the device d ignition 9 different from the first driver. Thus, when an electric current of an intensity greater than the predetermined value passes through phase 10 and the conductive portion 8, the fuse 40 is triggered. As a result, the resistance across the terminals of the fuse 40 increases, thereby generating a sufficient potential difference in order to actuate the ignition device 9 and thus cut off the electric current. It is general knowledge of a person skilled in the art to choose the characteristics of the fuse to be used in order to obtain the cut-out at the desired intensity level. In particular, it can be noted that the fuse does not need to hold a high voltage, which makes it possible to use fuses having a relatively low breakdown voltage. The cut-off device can be used in a system implementing a voltage of less than 100 V, for example.

It is advantageously possible to place at least one resistor or a diode in series (not shown) on the line connecting the fuse 40 to the ignition device 9 in order to reduce the intensity flowing in the ignition device 9 and therefore avoid any degradation of the latter in the presence of the nominal current.

The conductive portion 8 is present on a support 18. The support 18 has, in the example illustrated, a drawer structure intended to be engaged in an opening 22a of the side wall 22 of the body 11. The support 18 defines a relief in hollow 20 located below the conductive portion 8 when the device 1 is in the first configuration. The support 18 has a groove 19 in which the conductive portion 8 is housed. The conductive portion 8 is intended connected to a phase 10 of the supply circuit. This connection can for example be carried out by welding. The ends of the conductive portion 8 are connected to a phase 10 of the supply circuit.

The example of device 1 of the figure 1 further comprises a movable cut-off element 15 formed of an electrically insulating material, for example polyetheretherketone (PEEK GF40) or polyphenylene sulfide (PPS). The cutting element 15 sealingly separates the first chamber 7 from the second chamber 12. The cutting element 15 is located between the first 7 and the second 12 chambers. The cut-off element 15 has at least one relief 17 opposite the conductive portion 8. The cut-off element 15 has a seal 16 formed of an elastically deformable material which is supported on a side wall 22 of the body 11. The side wall 22 surrounds the first 7 and second 12 chambers. The side wall 22 of the body 11 defines an interior volume in which the first 7 and second 12 chambers are present and in particular in which the fuse 40 is present. More specifically, in the example illustrated, the fuse 40 is present in the second chamber 12. The relief 17 is in the form of a portion of extra thickness. In the example illustrated, the cutting element 15 has a single relief 17 intended to break the conductive portion 8. The invention is not limited to a particular shape for the distal end 17b of the relief 17 as long as the relief 17 is able to break the conductive portion 8 by impact with the latter. The distal end 17b of the relief 17 can thus for example have a planar shape as illustrated or even a pointed or rounded shape. As will be detailed below, the cut-off element 15 is configured to move along the axis of movement X following the actuation of the pyrotechnic initiator 3. When the device 1 is in the first configuration, the recessed relief 20, the conductive portion 8 and the relief 17 are superimposed along the axis X.

An example of assembly of the various elements of the breaking device 1 illustrated in Figures 1 to 3 will now be described.

Initially, the body 11 is molded onto the pyrotechnic initiator 3. The cut-off element 15 is then forcefully inserted through the bottom 25. As illustrated in the figure 2 , the cutting element 15 has a positioning relief 26, here in the form of a notch, intended to cooperate with a relief present on the internal wall of the body. This cooperation makes it possible to block the cutting element 15 in rotation and thus prevent the latter from rotating around the axis X when the first chamber 7 is pressurized by the pyrotechnic initiator 3. The conductive portion carrying the fuse 40 is then placed in the groove 19 of the support 18. The support 18 is then inserted through an opening 22a in the side wall 22 of the body 11 transversely to the axis of movement X and the wires 24a and 24b are then soldered to the terminals of fuse 40. The breaking device 1 illustrated in figure 3 This is thus obtained which is ready to be connected to a supply circuit, for example by soldering phase 10 on the conductive portion 8.

The cut of the electric current by the cut-off device 1 of the figure 1 will now be described in connection with Figures 4A to 4C .

The device 1 is initially in the first configuration in which an electric current (arrow I) can flow in phase 10 and in the conductive portion 8 (the fuse 40 is on). When the device 1 is in the first configuration, the cut-off element 15 is in a first position, called the high position. When the intensity of the current flowing through the conductive portion 8 exceeds the predetermined value, the fuse 40 trips. Thus, the resistance at the terminals of the fuse increases, which makes it possible to actuate the pyrotechnic initiator. The actuation of the pyrotechnic initiator 3 allows the switching device to pass from the first configuration to a second configuration in which the circulation of electric current in the conductive portion 8 is interrupted (conductive portion disconnected). More precisely, the actuation of the pyrotechnic initiator allows the combustion of one or more pyrotechnic charges 4 in order to generate a combustion gas (arrows F) which will pressurize the first chamber 7 (see figure 4A ). This pressurization of the first chamber 7 sets in motion the cut-off element 15 towards the conductive portion 8. The movable cut-off element 15 is configured not to be broken during the pressurization of the first chamber 7 by the pyrotechnic initiator . In the example illustrated, the cut-off element 15 is configured to move without deforming when the device 1 passes from the first configuration to the second configuration. The cutting element 15 is driven in a translational movement along the axis X in the direction of the conductive portion 8 during the transition from the first configuration to the second configuration. In particular, due to the presence of the positioning relief 26, the movement of the cut-off element 15 does not include a component of rotation about the axis X during the transition from the first to the second configuration. Following its movement, the cutting element 15 impacts the conductive portion 8 and thus breaks the latter (see Figures 4B and 4C ). This breaking of the conductive portion 8 into several separate parts 8a and 8b makes it possible to prevent the flow of electric current and therefore to guarantee the security of the system. The breaking element is configured as illustrated to impact the conductive portion 8 transversely, for example perpendicularly, to the direction of circulation of the electric current in this portion 8. In the example illustrated, the relief 17 is housed in the relief in hollow 20 of the support 18 when the device 1 is in the second configuration, the relief 17 thus abutting on the bottom of the hollow relief 20. When the device is in the second configuration, the cut-off element 15 is in a second position, called the low position and the current is cut. This example of a device according to the invention can advantageously make it possible to produce a particularly rapid power cut, for example in approximately 0.2 ms. In the example illustrated, the relief 17 impacts the conductive portion at a region separate from that where the fuse 40 is present. The initiator can be chosen to present dielectric insulation after operation greater than the system voltage.

A maintenance operation can be performed after cutting the supply circuit in order to remove the cut-off device in the second configuration and replace it with a break in the first configuration. The supply of the electrical device by the supply circuit can then resume.

The example of switching device 1 which has just been described in connection with the Figures 1 to 3 and 4A to 4C is such that (i) the current is cut off by breaking the conductive portion 8 during the impact of the latter with the movable breaking element 15, and (ii) the fuse 40 is present in the second chamber 12 in which the conductive portion 8 is present. Other configurations can be envisaged in the context of the present invention as will be described below.

We represented at the figure 5 a detail of a switching device according to an alternative embodiment of the invention. In this variant, the breaking device comprises a plurality of conducting portions 80. The breaking device comprising this plurality of conducting portions can be intended to be connected to a polyphase circuit. In the example illustrated, the breaking device is intended to be connected to a three-phase circuit. The number of conductive portions 80 of the breaking device can be equal to the number of phases of the circuit. Each of the conductive portions 80 is intended to be connected to a separate phase of this circuit. Each conductive portion 80 has a fuse 40 which is connected to it in series. The rest of the cut-off device can be similar to that described in the figure 1 with the difference that the pyrotechnic initiator has a plurality of ignition devices each connected to the terminals of a separate fuse. The conductive portions 80 are spaced from each other by a non-zero distance. In this case, the relief of the cut-off element is intended to break the various conductive portions 80 simultaneously when the pyrotechnic initiator is actuated. In the same way as described above, when an electric current of an intensity greater than the predetermined value passes through one of the phases, the resistance at the terminals of the fuse associated with this phase increases, thereby generating a sufficient potential difference at the terminals of the fuse in order to activate the ignition device connected to this fuse and thus cut off the electric current. In the case where the circuit is polyphase, the implementation of such a cut-off device advantageously makes it possible to avoid situations in which at least one phase remains on after switching off another phase, given that after actuation of the device cutting all portions conductors are simultaneously broken, thus preventing any flow of current in the circuit.

We represented at the figure 5A a detail of a cut-off device outside the invention. In this example, the conductive portion 90 is formed from a single material and has a thinned area 140 of reduced width and possibly of reduced thickness. This thinned area 140 is configured to melt when the intensity of the current flowing through the conductive portion 90 exceeds the predetermined value. An initiator is also connected to the terminals of the thinned area 140 so as to trigger the cut-off of the current when the resistance of the thinned area 140 increases, in a similar manner to that described above. In this case, the fusible element is constituted by a necking of the conductive portion itself, without having to attach a third fusible element in series with it.

We represented at the figure 6 a variant of switching device 111 according to the invention in the first configuration, that is to say in a configuration in which an electric current (arrow I) can flow in phase 110 of the supply circuit and in the conductive portion 180. In the example illustrated, the device 1 comprises a body 114 inside which are present: a first chamber 7, a second chamber 12 and a third chamber 128. The pyrotechnic initiator 3 has the same structure as in the example of figure 1 and the same reference numbers were used at the figure 6 to designate the same elements as in the figure 1 .

The first chamber 7 constitutes a pressurization chamber and is in communication with an outlet S of the pyrotechnic initiator 3. In the example of the figure 6 , an electrically conductive portion 180 is present in the second chamber 12. However, unlike the example of the figure 1 , the fusible element is not present in the second chamber 12. Indeed, in this example, the device 111 comprises a third chamber 128 in which are present a fusible element 130 as well as a powder 131 of an insulating material electricity. The fusible element 130 is here present inside the insulating powder 131. Such a configuration makes it possible to further improve the reliability of the breaking device, by improving the resistance over time of the fusible core. The electrically insulating material can for example be silica. The fuse element 130 may be constituted by the fuse core of a commercial fuse which has been separated from its insulating envelope. The fusible element 130 is connected to phase 110 of the circuit via the electrical connector 110a and this element 130 is, in addition, connected in series to the conductive portion 180 via the electrical connector 180a. The conductive portion 180 is, for its part, connected to phase 110 of the circuit in order to allow, in normal operation, the circulation of an electric current in the circuit through the breaking device 111.

Furthermore, the electrical conductors 5 are each connected to a separate terminal of the fuse element 130. As in the example of the figure 1 , the side wall 122 of the body 114 has channels 123a and 123b through which electrical conductors 124a and 124b extend. The first electrical conductor 124a connects a first terminal of the fuse element 130 to a first conductor 5 of the ignition device 9. The second electrical conductor 124b connects a second terminal of the fuse element 130, different from the first, to a second conductor 5 of the ignition device 9 different from the first conductor. Thus, when an electric current of an intensity greater than the predetermined value passes through phase 110, the resistance at the terminals of the fusible core increases, thus generating a sufficient potential difference in order to actuate the ignition device 9 and thus cut off the electrical current. In the same way as in the example of the figure 1 , actuation of the ignition device 9 makes it possible to set in motion the movable cut-off element 15 which will break the conductive portion 8 by impact with the latter in order to interrupt the circulation of the electric current in the circuit.

In the example of the figure 6 , the first 7, second 12 and third 128 rooms are superimposed. The second chamber 12 is positioned between the first chamber 7 and the third chamber 128 in this example. The conductive portion 180 is present on a support 118 having a drawer structure similar to that described in connection with the Figures 1 to 3 . In the example of the figure 6 however, the channels 123a and 123b extend through the drawer 118 so as to be able to connect the connectors 5 to the terminals of the fuse element 130.

The actuation of the initiator results in the movement of the movable cut-off element 15 towards the conductive portion 180 in order to break the latter, in a manner similar to that described in Figures 4A to 4C .

The examples which have just been described bring about a disconnection of the conductive portion by breaking of the latter by the movable breaking element. It will now be described, in connection with the Figures 7A, 7B and 8 , an example of a switching device outside the invention in which the disconnection of the conductive portion is carried out in a different manner.

The breaking device 211 comprises a hollow body 216 of electrically insulating material delimiting a cavity 219, a pyrotechnic initiator 223 and a conductive portion comprising two primary electrical conductive pads 213, 214 which open into the cavity 219. In this example, the conductive portion thus comprises a first electrically conductive element (conductive pad 213) and a second electrically conductive element (conductive pad 214). The first 213 and the second 214 electrically conductive elements are offset along the longitudinal axis Y of the cavity 219 in the example illustrated.

The cut-off device 211 also comprises a movable cut-off element 220 configured to move in the cavity 219. In the example, the cavity 219 is cylindrical and the movable cut-off element 220 is itself essentially cylindrical. The movable breaking element 220 comprises, in the example illustrated, a first part formed of an electrically insulating material and a second part formed of an electrically conductive material. The movable cut-off element 220 comprises a split tube 221 which includes at least one electrically conductive element. In the example illustrated on Figures 7A, 7B and 8 , the split tube 221 is fully conductive of electricity. The split tube 221 has a slot 229. The movable cut-off element 220 further comprises a sliding drawer 222 made of an electrically insulating material forming a piston, adapted to move inside the cavity, so as to entrain with it the split tube 221. One could alternatively use a movable cut-off element entirely formed of an electrically conductive material in the example of cut-off device illustrated in the figure 7A . Such an element could comprise a first part forming a tube similar to the conductive tube 221 illustrated and a second part in the form of a disc extending transversely with respect to the Y axis and obstructing the first part.

When the device 211 is in the first configuration as illustrated in the figure 7A , the split tube 221 (third conductive element) provides the electrical connection between the studs 213 and 214 (first and second conductive elements). This allows current to flow in the circuit through the conductive portion of the cutoff device 211.

According to the example, the pyrotechnic initiator 223 comprises a pyrotechnic gas generator, known per se, installed in the hollow body so as to communicate with the cavity 219. A pressurization chamber 225 is defined between the pyrotechnic initiator 223 and one of the axial end faces of the piston 222. In the example, more particularly, the piston 222 comprises a cavity 226 in its upstream face, directed towards the pyrotechnic initiator 223, and this cavity 226 constitutes a part of the pressurizing chamber 225. In the initial position where the sliding drawer 222 is practically in contact with the initiator 223, that is to say with the pressurizing chamber 225 reduced to its minimum volume, both electrical conductor pads 213, 214 are electrically connected to each other, via the split tube 221 in a first position, called the initial position. The electrical contact being made via the third conductive element (here the split tube 221), as mentioned above.

The two conductive pads have two coaxial rings 213a, 214a offset axially along the axis Y (corresponding to the direction of movement of the movable breaking element 220) and these rings 213a, 214a are at least in close contact with the conductive part of the movable cut-off element (here the split tube 221) when it is in said first position. In the example, the internal faces of the rings 213a, 214a are flush with the wall of the cavity 219. Advantageously, in said first position, the split tube 221 is engaged by forced interlocking between the rings 213a, 214a of said primary conductive pads 213, 214 , which guarantees an excellent electrical connection between said primary conductive pads throughout the period preceding the actuation of the switching device 211.

As illustrated in figure 8 , one of the rings 213a has in the illustrated example a fuse 240 which is connected to it in series. The fuse 240 is, in the example illustrated, integrated into the ring 213a with its insulating envelope. However, the implementation of a fuse element formed solely by the fuse core of a commercial fuse (without its insulating jacket) or by a thinned zone of the ring, is described in a manner similar to what has been described. upper. The support portion 212 of the pyrotechnic initiator 223 includes two through channels 212a and 212b. A first electrical conductor 240a extends through a first channel 212a so as to connect a first electrical conductor 223a of the pyrotechnic initiator 223 to a first terminal of the fuse 240. In the same way a second electrical conductor 240b s' extends through a second channel 212b so as to connect a second electrical conductor 223b of the pyrotechnic initiator 223, different from the first conductor 223a, to a second terminal of the fuse 240 different from the first. Thus, when a current of an intensity greater than the predetermined value passes through the ring 213a, the resistance of the fuse 240 increases so as to create at its terminals a sufficient potential difference to be able to actuate the pyrotechnic initiator 223. As a variant or in combination, a fuse element connected to the pyrotechnic initiator could be present on the electrical pad 214 by being connected in series to the latter.

When the pyrotechnic initiator 223 is actuated, the mobile cut-off element 220, and consequently the split tube 221, moves to a second position in the cavity ( figure 7B ), following the pressurization of the pressurizing chamber 225. In this second position, the split tube 221 is released from the pad 213, this makes it possible to prevent the electrical connection between the two conductive pads 213, 214 and to interrupt current flow in the circuit. In the example illustrated, when the device 211 is in the second cut-off configuration (that illustrated in the figure 7B ), the split tube 221 is separated from the stud 213 and is in contact with the stud 214. We also describe the case where the split tube is neither in contact with the stud 213 nor with the stud 214 when the device is in the second configuration.

The figure 8 shows how a cut-off device 211 as described can be produced in a simple and economical manner. The hollow body 216 is defined by the assembly of two housing elements 230, 231, respectively left 230 and right 231. The housing element 230 comprises two tapped blind holes 232 surmounted by an imprint open laterally 233a, 233b and 233c and the shape is defined to accommodate a part of each electrically conductive pad 213, 214 and a part of the support 212 of the pyrotechnic initiator. Each electrically conductive stud comprises a ring 213a and 214a extended laterally by a connection bar 213b and 214b projecting outside the insulating hollow body so as to be able to be connected to the electrical circuit external to the breaking device 211. The second element of housing 231 has two through holes 236 allowing the insertion of fixing screws 237. In the same way as the first housing element 230, it further comprises an imprint open laterally 234a, 234b and 234c and whose shape is defined to accommodate part of each electrically conductive pad 213, 214 and part of the support 212 of the pyrotechnic initiator. The support 212 is mounted between the two housing elements 230, 231 and comprises a bore 238 which receives at its end the initiator 223. The initiator 223 is mounted inside said support 212 so as to define the setting chamber under pressure 225 inside said bore 238. As mentioned previously, the split tube 221 is forcibly engaged in each of the two rings 213a, 214a.

In this way, in said first, initial position, the two coaxial and axially offset rings 213a, 214a are electrically connected via the split metal tube 221. In the example illustrated, the insulating drawer 222 is inserted inside of the sliding split tube 221. A first part or upstream part 241, of cylindrical shape, of diameter substantially equal to the diameter of the cavity 219, slides along the internal faces of said cavity. In its upstream face, directed upwards on the Figures 7A, 7B and 8 , the first part 241 comprises a cavity 226, here also substantially cylindrical, which partially delimits the initial volume of the pressurizing chamber 225. As emerges from the figure 8 , the first part 241 comprises two circumferential grooves 261, 262, spaced axially from each other, and each receiving an O-ring seal 263, 264. Thus, the piston 222 closes the pressurization chamber 225 and allows rapid pressure increase in the closed environment of this bedroom. Thus, the gases generated in the pressurizing chamber 225 do not infiltrate towards the conductive rings 213a, 214a.

A groove is advantageously formed in at least one of said grooves and configured to form a calibrated passage for the evacuation of air from the pressurization chamber during the mounting of the piston 222 in the support 212 of the initiator pyrotechnic 223. The piston 222, located at least partly upstream of the split tube, has the function of transmitting to said tube 221 the pressure force generated by the gases in the pressurizing chamber 225 and allowing the cutting of the circuit by moving said tube 221. The first part 241 is extended by a second downstream part 242, of slightly smaller diameter chosen to allow its insertion, possibly by force, inside the split tube once it is inserted between the rings 213a, 214a. This second part can act as a guide element for the split tube, during its movement inside the cavity 219. It can also, in an advantageous embodiment, form a complementary clamping element of the split tube against the rings 213a, 214a. After triggering of the pyrotechnic initiator 223, the situation is illustrated in the figure 7B . The electrical connection between the two studs 213, 214 is interrupted and the flow of electric current through the conductive portion of the switching device 211 is thus interrupted. It will be noted that the piston 222 has here, on a part located directly upstream of the split tube, a diameter equal at most to the external diameter of this tube once inserted between the rings. In the example illustrated, the diameter of the upstream part of the piston is even slightly smaller than that of the split tube, so that the piston, driving the split tube, can slide easily between the rings, without remaining blocked. This is made possible here by a slight difference in diameter between the most upstream part of the cavity along which the piston slides (formed here by the bore of the initiator support) and its downstream part (formed by the housing elements), wider, into which the rings open.

As can be seen in the drawings, the cavity 219 is extended downstream by a guide portion 245 which makes it possible to guide the split tube 221 when it passes from the first to the second position and to ensure that it ci a straight path. A damping pad 29 is inserted into the bottom of the cavity 219. If necessary, this damping pad 29 has for the purpose of reducing the energy of the impact of the split conductive tube 221 and of the insulating piston 222 when the two parts come into contact on the bottom of the body 216.

We represented at the figure 9 a first example of a secure electrical system 30 according to the invention. The secure electrical system 30 comprises a secure supply system 2 connected to an electrical device 31 intended to be supplied by this supply system 2. The supply system 2 comprises a single-phase supply circuit comprising an electric generator G and a phase 10 connected to this generator G. The generator G can for example be an alternator. Generator G can be connected to a heat engine such as an internal combustion engine or a turbojet. As a variant, the generator G may be part of an installation such as a power station producing an alternating current. In this example, the cut-off device 1 illustrated in the figure 1 is linked to phase 10 as detailed above. The cut-off device 1 is mounted in series with the generator G and the electrical device 31. The cut-off device 1 is present between the generator G and the electric device 31. The generator G is present upstream of the cut-off device 1 and the electrical device 31 is present downstream of the breaking device 1. The terms “upstream” and “downstream” are used here with reference to the direction of the electric current in the supply circuit (arrow I). As explained above, when the intensity of the current passing through phase 10 exceeds the predetermined value, the triggering of the fuse 40 present in the breaking device 1 makes it possible to actuate the pyrotechnic initiator 3 and therefore the cutting of the current flowing in the circuit.

The figure 10 shows another example of a secure electrical system and power system 300 according to the invention. In the example of the figure 10 , a structure similar to that of the figure 9 was used in which a control element 37 of the electrical device 31 was added. This control element 37 is connected to the ignition device of the cut-off device 100. The control element 37 is configured to actuate the pyrotechnic initiator when an operating parameter of the electrical device reaches a predetermined value. This makes it possible to cut off the electric current by the cut-off device 100 also in the event of a malfunction of the electric device. 31 and not only in the event of an overcurrent in the circuit. The control element 37 comprises for example a temperature sensor configured to measure the temperature of the electrical device 31. As a variant or in combination, the control element 37 may comprise a pressure sensor configured to measure the pressure of a part at least of the electrical device 31. Thus, the control element 37 can be configured to actuate the pyrotechnic initiator when the temperature of the electrical device 31 or the pressure of a part of said device 31 exceeds a predetermined value and this in order to guarantee the security of the system 300 when a malfunction is observed.

The secure electrical systems 30 and 300 which have just been described may be mounted in a vehicle such as an aircraft or a train or be present in an industrial installation.

Claims (9)

1. A breaker device (1 ; 100 ; 111) for connecting to an electrical circuit, the device comprising at least one pyrotechnic initiator (3) and a body (11 ; 114) having present therein:

   - a pressurizing chamber (7) in communication with an outlet (S) from said pyrotechnic initiator (3) and constituting a first breaker device chamber;

   - at least one electrically conductive portion (8 ; 180) for connection to the electrical circuit, at least a fraction of the conductive portion (8 ; 180) being present in a second chamber (12) that is present in the body (11 ; 114) ;

   - at least one fusible element (40 ; 130) connected in series with the conductive portion, the initiator being connected to the terminals of said fusible element and said fusible element being configured to trip when the current passing through it exceeds a predetermined value, thereby actuating the initiator; and

   - a movable breaker element (15) separating the first chamber (7) from the second chamber (12) and presenting at least one projecting portion (17) made of electrically insulating material, said at least one projecting portion facing the conductive portion (8 ; 180);
   the pyrotechnic initiator being configured to cause the breaker device to pass from a current-passing first configuration to a circuit-breaking second configuration, the breaker device being characterized in that the movable breaker element is moved towards the conductive portion in order to break it by impact against the projecting portion in a zone that is distinct from the zone where the fusible element is present on passing from the first configuration to the second, the fusible element being present either in the second chamber and being connected with its insulating shell to the conductive portion, or in a third chamber (128) distinct from the second chamber wherein a powder (131) of electrically insulating material also being present in the third chamber.
2. A device according to claim 1, wherein the fusible element (40 ; 130) is a separate component connected to the conductive portion.
3. A breaker device (1 ; 111) according to any one of claims 1 or 2, the device having a single conductive portion (8 ; 180).
4. A breaker device according to any one of claims 1 or 2, wherein the breaker device has a plurality of conductive portions (80), a respective fusible element (40) being connected in series with each of the conductive portions, the initiator being connected to the terminals of each fusible element and each fusible element being configured to trip when the current passing through it exceeds the predetermined value so as to actuate the initiator.
5. A secure electrical system (30 ; 300) comprising at least:

   - a secure power supply system (2 ; 200) comprising at least:

   - a breaker device (1 ; 100) according to any one of claims 1 to 4 ; and

   - a power supply circuit connected to the breaker device, said at least one conductive portion (8) being connected to a phase (10) of the power supply circuit; and

   - an electrical device (31) connected to said power supply system (2 ; 200) in order to be powered thereby.
6. A system (300) according to claim 5, further comprising a monitor element (37) for monitoring the electrical device and configured to actuate the initiator (3) when the value of an operating parameter of the electrical device reaches a predetermined value.
7. A system (300) according to claim 6, the operating parameter being pressure or temperature.
8. A vehicle including at least one secure electrical system (30 ; 300) according to any one of claims 5 to 7.
9. An installation including at least one system (30 ; 300) according to any one of claims 5 to 7.

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