EP2232518A2

EP2232518A2 - Protection device against overvoltage including a disconnection accessory

Info

Publication number: EP2232518A2
Application number: EP08872654A
Authority: EP
Inventors: Vincent Crevenat; Boris Gautier
Original assignee: ABB France SAS
Current assignee: ABB France SAS
Priority date: 2007-12-18
Filing date: 2008-12-18
Publication date: 2010-09-29
Anticipated expiration: 2028-12-18
Also published as: US20110013330A1; CN101946297B; CN101946297A; FR2925216B1; US8514538B2; FR2925216A1; WO2009103896A8; WO2009103896A3; WO2009103896A2; EP2232518B1; ES2442503T3

Abstract

The invention relates to a device for protection against overvoltage that comprises: at least one overvoltage protection member (11); a thermo-sensitive device capable of deformation on the basis of the temperature thereof; a thermal link between the at least one protection member and the thermo-sensitive member; and at least one mechanical member (15) for interaction with the thermo-sensitive member and capable of interaction with a system for triggering an electric cut-off apparatus (2). The thermo-sensitive member (17) and the at least one mechanical member (15) are arranged so that, when the thermo-sensitive member exceeds a given temperature threshold, the thermo-sensitive member generates, due to the deformation thereof, a movement of said at least one mechanical member (15) that actuates the system for triggering the electric cut-off apparatus.

Description

OVERVOLTAGE PROTECTION DEVICE HAVING A DISCONNECTION AUXILIARY

The present invention relates to the general technical field of equipment protection devices or electrical installations against electrical disturbances, especially against transient overvoltages due in particular to a lightning strike. The present invention relates more particularly to a protection device, such as a varistor surge arrester, associated with or intended to be associated with an electrical breaking device such as a circuit breaker.

It is known to ensure the protection of an electrical installation against overvoltages using devices including at least one overvoltage protection component, in particular one or more varistors and / or a spark gap. In the most frequent cases, a varistor is connected between a phase and the neutral of the electrical installation while a spark gap is connected between the neutral and the earth.

In the event of failure of the protective component or component, these devices comprise a disconnection system for isolating the protection component or components of the electrical installation for safety reasons.

In particular, in the case of a varistor connected between a phase and a neutral, it is conventional to provide thermal protection which is imposed by the international standards applicable to these devices. The thermal protection is used to disconnect the varistor of the electrical installation to be protected in case of excessive heating of the varistor, for example beyond 150 ⁰ C. This excessive heating of the varistor is due to the increase of the current of leakage - usually a few tens of milliamperes - through it due to aging. In this case, it is called thermal runaway of the varistor.

Thermal protection often consists of one or more low temperature welds holding in place an elastically constrained element, the fusion of the weld or welds allowing the displacement of this element with the effect of opening the circuit of the varistor. Thermal protections of this type are described in particular in EP-A-0 716 493, EP-A-0 987 803 and EP-A-0 905 839.

Sometimes the thermal protection is also based on an electronic current measurement as described for example in FR-A-2,873,510, which has the drawback of being expensive.

It can also be provided specific protection against short circuits and separate from the thermal protection. It is used to disconnect the varistor in case of short circuit franc of it following for example a major love at first sight. This is usually a magnetothermic circuit breaker.

Whether for thermal protection or short-circuit protection, it is generally planned that the disconnection of the varistor takes place without causing the opening of the general breaking devices of the electrical installation to ensure a continuity of service of the electrical installation.

The disadvantage is that the thermal protection and the short-circuit protection are distinct and each employs a respective breaking device. That of the thermal protection can have a low power of cut while that of the protection against short circuits must be able to cut very high currents. But the fact of using two cut-off devices has the disadvantage of both increasing the size of the protective device and its cost.

It has thus been proposed in EP-A-I 607 995 an overvoltage protection device, comprising a protection module and a circuit breaker. The protection module comprises a varistor and a spark gap, which are connected to the electrical network to be protected by means of the circuit breaker. To ensure the disconnection of the varistor and the spark gap in the event of a fault of one of them, the protection module comprises separation means to cause the opening of the circuit breaker. More specifically, these separation means consist of a thermal pin disposed on a range in thermal connection with the varistor and an electric fuse connected in series with the spark gap. The thermal pin is made of metal alloy or heat-fusible material low melting temperature. When the pin or fuse melts or breaks, a mechanical actuation system ensures the tripping of the circuit breaker and consequently the disconnection of the varistor and the spark gap of the electrical network. More particularly, the mechanical actuation system comprises a lever connected to the thermal pin and another lever connected to the fuse, these levers being biased by a respective return spring. In the case where the pin or fuse melts or breaks, the corresponding lever acts on a control centralizer under the effect of the return spring, the control centralizer actuating the trigger mechanism of the circuit breaker through a mechanical connection.

But this device has several disadvantages. Thus, a pin of thermo-fusible material is not very precise about the temperature at which it will melt or break and thus cause the tripping of the circuit breaker. The low-melting metal alloy pion provides better accuracy, but has the disadvantage, besides its higher price, of being very delicate and generally contains pollutants of the lead or cadmium type. Furthermore, EP-A-1 447 831 describes a lightning surge protection device combining a surge arrester block and a magnetothermic circuit breaker, the surge arrester block comprising a varistor. According to one embodiment, the arrester block comprises a thermal disconnector thermally connected to the varistor 12. The thermal disconnector is constituted by a low temperature weld cooperating with an elastic blade triggering the circuit breaker after fusion of the weld under the effect of heat a thermal runaway of the varistor. This embodiment has disadvantages similar to those mentioned above for the metal alloy heat pin.

According to another embodiment, this document teaches to thermally connect the bimetallic circuit breaker to the varistor. If the bimetallic strip of the circuit breaker does not undergo a sufficient deflection when it is crossed by the currents appearing during the thermal runaway of the varistor, the thermal connection between said varistor 12 and the bimetallic strip generates a sufficient deflection to cause the tripping of the circuit breaker which disconnects the surge arrester block from the electrical network. But this embodiment also has disadvantages. In particular, it is not possible to use conventional commercial circuit breakers because they are not intended to thermally connect their bimetallic to an element outside the circuit breaker housing. Such a device requires modifying the design of the circuit breaker to be able to effectively communicate the heat generated by the varistor at the bimetallic circuit breaker. In addition, the circuit breaker can not be chosen freely considering that the bimetallic thereof must be adapted to cause the tripping of the circuit breaker at a given critical temperature reached by the varistor.

It is also known from WO 2004/064213 an overvoltage protection device comprising a varistor and a means of interruption of the electric current flowing through the varistor. In a variant, this interruption means comprises a sliding rod carrying an electrical contact element for opening or closing the electrical circuit of the varistor. In normal operation, the rod is prestressed in the closed position of the contact by a stop in the form of a plate arranged at the end of a bimetallic strip. The bimetal is mounted and positioned in the device to be sensitive to heat released by the varistor. In case of excessive heating, the bimetallic bends so as to disengage the stop to release the rod which is biased by a spring towards the open position of the contact. In another variant, the varistor is fed through the bimetal and a conductive element arranged at one end of the bimetallic strip. In normal operation, this conductive element is in electrical contact with a connector, which allows to feed the varistor. In case of excessive heating, the bimetallic bent to move the conductive element away from the connector, which has the effect of interrupting the power supply of the varistor. In addition, an insulating screen is interposed between the conductive element and the connector to prevent reclosing of the circuit when the bimetallic returns to its initial position after cooling.

In both variants, these devices have the disadvantage of requiring a careful design of the bimetallic strip, as well as good mounting accuracy. Indeed, of these depends the contact force applied at the electrical contact of the interruption means in normal operation which must be able to flow very large currents in case of surges on the power grid related to lightning. In addition, the deformation tolerance of bimetals as a function of temperature requires an individual adjustment similar to that used to adjust the sizes of modular circuit breakers. Furthermore, the slow and progressive opening of the contacts does not allow a break of a short circuit current.

The object of the present invention is to provide a device for protection against overvoltages at least partially overcoming the aforementioned drawbacks. More particularly, the invention aims to provide such a device that is simple and reliable implementation.

To this end, the present invention provides an overvoltage protection device, comprising: at least one overvoltage protection component; a thermosensitive member capable of deforming in dependence on its temperature; a thermal connection between the at least one protective component and the thermosensitive member; and at least one mechanical member for cooperating with the thermosensitive member and adapted to cooperate with a triggering system of an electrical breaking device; in which the thermosensitive member and the at least one mechanical member are arranged so that, when the thermosensitive member exceeds a given temperature threshold, the thermosensitive member causes, due to its deformation, a displacement of said at least one mechanical member capable of to actuate the triggering system of the electric switchgear.

In preferred embodiments, the invention includes one or more of the following features: the thermosensitive member and the at least one mechanical member are arranged so that, when the thermosensitive member exceeds a given temperature threshold, the thermosensitive member displaces, due to its deformation, said at least one mechanical member to actuate the system of tripping of the electrical breaking device; the thermosensitive member is chosen from the group consisting of: a bimetallic strip, a heat-shrinkable element and a deformable capsule filled with a fluid causing a deformation of the capsule when the fluid exceeds said given temperature threshold, the fluid preferably being a fluid refrigerant; the thermosensitive member has a bistable deformation property conferring on it a stable undeformed configuration as long as its temperature does not exceed the given temperature threshold, and a stable configuration deformed when its temperature exceeds the given temperature threshold; said at least one mechanical member is a one-piece element through which the thermosensitive element is able to actuate, due to its deformation, the trigger system of the breaking device; said at least one member comprises a mast member pivotally mounted about an axis of rotation and on which mast is arranged:

A trigger bar designed to cooperate with the triggering system of the breaking device, said trigger bar extending in a direction substantially orthogonal to the axis of rotation of the mast; and

A rigid pallet radially offset relative to the axis of rotation of the mast, and said pallet is arranged so that the thermosensitive member under the effect of its deformation exerts a force on the pallet to rotate the mast; said at least one mechanical member comprises a first movably mounted member and a second movably mounted member on which is arranged a trigger bar provided to cooperate with the trigger system of the switchgear: the first member is held in a first position by elastic biasing against a stop and the thermosensitive member is arranged to cause due to its deformation disengagement of the first member of the stopper when the thermosensitive member exceeds said given temperature threshold, the disengagement of the first member of the abutment causing a moving the first member beyond the abutment by elastic bias, the second member being coupled to the first member so that said displacement of the first member causes a displacement of the first member; second member adapted to actuate the trigger system of the switchgear; in this latter embodiment, the first member may be pivotally mounted or tilting about an axis, the thermosensitive member being arranged to cause the disengagement of the first member of the stop by pivoting or tilting the first member, said displacement of the first member beyond the stop being a displacement in translation along the axis of pivoting or tilting of the first member; alternatively, said at least one mechanical member further comprises a third member, the stop being arranged on the third member and the thermosensitive member being arranged to cause the disengagement of the first member of the stop by moving the third member; in these two variants, the second member is preferably pivotally mounted; the device comprises a locking system for locking said at least one mechanical member in an actuating position of the triggering system of the cut-off device when the thermosensitive member has caused, due to its deformation, a displacement of said at least one member mechanical able to actuate the triggering system of the electric switchgear; the locking system is provided by a bistable hysteresis deformation property of the thermosensitive member; the locking system comprises:

A fixed stop having two adjacent support faces substantially orthogonal to each other; and

An elastic tongue arranged on said at least one mechanical member; the abutment and the elastic tongue being arranged so that:

• the elastic tongue is prestressed against the first bearing face when the thermosensitive member has not yet caused due to its deformation a displacement of said at least one mechanical member; and

The elastic tongue comes to be positioned irreversibly against the second bearing face under the effect of the intrinsic restoring force of the elastic tongue, as soon as the thermosensitive member has caused, due to its deformation, a displacement of said at least one a mechanical member capable of actuating the triggering system of the electric switchgear. the at least one protection component comprises a varistor and optionally a spark gap; the thermosensitive member has a purely thermomechanical operation; the thermosensitive member is in thermal connection by conduction with the protective component, either by direct contact with a face of the protective component, or by means of an electrode of the thermosensitive member, the greater part of the organ thermally sensitive being preferably disposed adjacent to a main face of the protective component; the device comprises a housing housing the at least one protection component and the thermosensitive member, the housing having a window through which said at least one mechanical member protrudes out of the housing to cooperate with the triggering system of the apparatus cutoff when the cutoff apparatus is arranged contiguous to the housing; the device comprises an electric switching device having a triggering system, wherein:

Said at least one mechanical member is arranged to cooperate with the triggering system of the electrical breaking device; and

The thermosensitive member and the at least one mechanical member are arranged so that, when the thermosensitive member exceeds said given temperature threshold, the thermosensitive member causes, due to its deformation, said displacement of said at least one mechanical member, said at least one mechanical member actuating the triggering system of the electric switchgear under the effect of said movement; the device, includes:

A first housing housing said breaking device; and

A second housing housing the at least one protective component and the thermosensitive member; in which :

The first housing and the second housing are assembled, preferably removably;

The first housing has a first window giving access to the triggering system of the switching device; and

• the second housing has a second window through which the at least one mechanical member protrudes from the second housing and enters the first housing through the first window to cooperate with the trigger system of the switchgear. the switchgear and the protection component are electrically connected so that actuation of the tripping system of the switchgear causes the power supply of the protection component to be interrupted; the switchgear is a magnetic circuit breaker or a magnetothermic circuit breaker.

Other features and advantages of the invention will appear on reading the following description of preferred embodiments of the invention, given by way of non-limiting examples and with reference to the appended drawing, in which

FIG. 1 illustrates, using a simplified electrical diagram, the operation of a protection device according to the invention;

FIG. 2 schematically illustrates the assembly of a protection device according to the invention, which comprises a switching device and a protection module intended to be assembled, the functional part of the protection module according to a first embodiment being shown in an apparent way;

FIG. 3 represents a second embodiment of the functional part of a protection module according to the invention;

FIG. 4 represents a third embodiment of the functional part of a protection module according to the invention;

FIG. 5 shows the inside of the protection module comprising the functional part of FIG. 4, with the functional part in a non-tripping position of the associated breaking device;

FIG. 6 represents the inside of the protection module comprising the functional part of FIG. 4, with the functional part in a tripping position of the associated breaking apparatus;

FIG. 7 represents a fourth embodiment of the functional part of a protection module according to the invention;

- Figure 8a shows a fifth embodiment of the functional part of a protection module according to the invention, which makes use of a deformable capsule filled with fluid, shown here at room temperature;

- Figure 8b shows the functional part of Figure 8a, but in the tripping state;

FIGS. 9a and 9b schematically illustrate the state of the fluid capsule of FIGS. 8a and 8b in the undeformed state and in the deformed state;

FIGS. 10 to 14 illustrate a variant of the third embodiment; and

FIGS. 15 and 16 illustrate another variant of the third embodiment.

The overvoltage protection device according to the invention comprises at least one overvoltage protection component, preferably a varistor. It also comprises a thermosensitive member capable of deforming into dependence with its temperature. A thermal connection is provided between the protective component and the thermosensitive member. It is preferably a heat conduction bond, but it can also be a convective bond or radiation bond, or any combination thereof or two of them. Thus, in case of heating of the protective component, it communicates heat to the thermosensitive member. Therefore, the temperature of the thermosensitive member rises with that of the protective component.

Furthermore, the device comprises at least one mechanical member provided, on the one hand, to cooperate with the thermosensitive member and which is, on the other hand, able to cooperate with the triggering system of an electrical switchgear, the function of said at least one mechanical member being to allow the thermosensitive member to cause operation of the trigger system of the cutter device through it.

More specifically, the thermosensitive member and the at least one mechanical member are arranged so that, when the thermosensitive member exceeds a given temperature threshold, the latter causes due to its deformation a displacement of said at least one mechanical member, the displacement of the latter being such that said at least one mechanical member is able to actuate the trigger system of the electric switchgear. By operating its trigger system, the switchgear interrupts the passage of the electric current, that is to say its electrical contacts or pass to the open state.

On the contrary, before the thermosensitive member undergoes this deformation, said at least one mechanical member is in a position that does not cause actuation of the triggering system of the switchgear. In this state, the switchgear is on, that is, its electrical contact (s) are closed.

By appropriately choosing the aforementioned temperature threshold above which the thermosensitive member causes the tripping device to be tripped, this device effectively and simply provides a disconnection of the protection component (s) if their heating should become too important. and therefore dangerous. This temperature threshold is chosen above the temperature reached by the thermosensitive member when the device operates under conditions considered to be normal, that is to say conditions in which the protection component satisfactorily ensures the protection of the electrical installation to which the device is connected and this safely, especially without excessive heating considered excessive. On the contrary, this temperature threshold is advantageously chosen to correspond to a temperature of the component of protection considered abnormal, but preferably below a temperature level considered to be dangerous. Generally, this temperature threshold is chosen to meet the safety requirements required by the applicable safety standards. This temperature threshold is preferably between 100 ° C. and 160 ^° C., and particularly preferably between 135 ° C. and 140 ^° C., which generally makes it possible to meet the requirements of the applicable safety standards.

Thus, it is sufficient to couple the device of the invention with a switching device having a suitable trigger system by ensuring that said at least one mechanical member of the protective device cooperates with the trigger system and electrically connect the device protection device so that the protection device is electrically powered by the power lines to be protected by means of the switching device.

The protection device may include the switchgear with possibly the electrical connections between them already made. The protection device is then ready to be used by connection to the electrical network to be protected.

The device of the invention is particularly suitable for any overvoltage protection component that is likely to heat in the event of a malfunction.

The device according to the invention is particularly simple and reliable. The fact of resorting to a thermosensitive member capable of deforming in dependence on its temperature in order to ensure the detection of the temperature of the protective component and to actuate the cutting apparatus advantageously makes it possible to dispense with low temperature welds. It also allows the use of standard off-the-shelf devices such as circuit breakers without any modification. Furthermore, the thermal connection between the thermosensitive member and the protective component can be implemented in a particularly simple and effective manner, in particular by placing the thermosensitive member near the protection component, or even in contact with it directly or by through an electrode of the protection component.

Figure 1 shows a simplified electrical diagram of a protection device according to the invention. The device comprises a protection module 1 and an electrical switching device 2. The device is connected to an electrical network comprising a phase line P, a neutral line N and a ground line T.

The protection device is connected to the electrical network P, N with a connection in parallel with a load 3. The latter schematizes an electrical installation which should be supplied and protected, in particular against overvoltages. transients caused by a lightning strike or a maneuvering incident on the electrical network The protection module 1 and the switching device 2 are preferably integrated in respective modular housings 1a, 2a shown schematically in FIG. 2, before their juxtaposed assembly and their coupling on a rail. Alternatively, the casings 1a, 2a are provided to be mechanically coupled together before rail mounting.

The switching device 2 is for example a standard magnetothermic circuit-breaker comprising in series, between an input terminal D1 and an output terminal D5, a magnetic component 6 of the winding type, a thermal component 7 of the bimetallic type, and means 8. Preferably, the circuit breaker conventionally has a handle for manual reset in case of tripping. More generally, the cut-off device 2 can be of any suitable type having a mechanically actuable triggering system. The input terminal D1 is connected to the phase P and the output terminal D5 is electrically connected to an input terminal M9 of the protection module 1. An output terminal MlO of the protection module 1 is connected to the neutral N and is connected to the input terminal M9 via a protection component, preferably a varistor 11. The switching device 2 and the varistor 11 are connected in series between the phase P and the neutral N.

According to the embodiment shown diagrammatically in FIG. 1, the protection module 1 also comprises a spark gap 13 connected between the output terminal MlO and a second output terminal M 14, respectively connected to the neutral N and to the ground T. L spark gap 13 is optional and can be omitted.

The magnetic component 7 of the circuit breaker provides protection against short circuits of the varistor 11 alone or both of the varistor 11 and the spark gap 13. Usually, the thermal component 7 provides protection against so-called overload currents which persist in time. But with regard to the specific case of thermal runaway of the varistor 11, the protection is not provided by the thermal component 7 of the circuit breaker because the leakage current of the varistor does not generally reach a sufficient intensity to intervene. protection by the thermal component 7 or at least it is desirable to disconnect the varistor 11 from the power lines before the leakage current reaches such an intensity. It is in this case the actuating means 12 described below, which include in particular the thermosensitive member, which provide this protection. For this reason, the switching device can also be a magnetic circuit breaker without a thermal component since the protection module 1, in cooperation with the circuit breaker, sufficiently provides the function of thermal protection. However, it may be more economical to use a magnetothermal circuit breaker since exclusively magnetic circuit breakers are less common.

The protection module 1 comprises actuating means 12 intended to cooperate with a triggering system or mechanism of the breaking device 2, more precisely of the disconnector switch 8. These actuating means 12 do not form part of of the cutoff apparatus 2, but are distinct from it.

The actuating means 12 comprise the thermosensitive member which comprises a thermosensitive portion capable of deforming under the effect of a heating of the varistor 11. For this purpose, the thermosensitive portion is thermally connected to the varistor 11.

The actuating means 12 also comprise at least one mechanical member capable of cooperating with the triggering mechanism of the cut-off device 2. When its temperature exceeds a given threshold, the thermosensitive member actuates, due to its deformation, the mechanism of triggering the cutoff apparatus 2 via this at least one mechanical member. In other words, because of its change of geometry, the thermosensitive member itself acts on the trigger mechanism through this at least one mechanical member. The function of this at least one mechanical member is to transmit - and if necessary adapt - the movement of the thermosensitive member generated due to its deformation to the trigger mechanism of the breaking device 2 to actuate the latter.

In the preferred embodiment, this at least one mechanical member comprises a trigger bar 15 projecting laterally on the modular housing la, as illustrated in FIG. 2, preferably through a window, not shown, provided in the casing the. This trigger bar 15 is intended to engage in an opening 16 formed in the modular housing 2a, for the purpose of cooperation with the triggering mechanism of the cut-off device 2. In this respect, the apparatus of FIG. Cutoff 2 is advantageously a standard commercially available circuit breaker of the type having such an opening 16 for mechanical control auxiliary.

The thermosensitive member may be of any suitable type such as bimetallic, heat-shrinkable element or deformable capsule deforming under the action of a fluid that it contains. In the embodiments described below, the varistor January 1 has a substantially parallelepiped shape flattened to two major faces from the point of view of their area. The flattened character of the varistor is advantageous from the point of view of its bulk, but it could also have a different shape. In the embodiment of FIG. 2, the thermosensitive member is a bimetallic strip 17. The bimetallic strip 17 is in the form of a straight strip in a state that is not deformed by heating. The bimetallic strip 17 is mounted at one end on a connection electrode 11a of the varistor 11. This electrode 11a projects perpendicular to one of the main faces of the varistor 11. The bimetallic strip 17 is fixed on the electrode 1 ia by any appropriate means, in particular by a cold assembly process such as crimping or riveting or by welding. The trip bar 15 is fixed on the opposite end of the bimetallic strip 17. Alternatively, the trip bar 15 is provided in one piece with the bimetallic strip 17. As can be seen in FIG. 2, the bimetallic strip 17 extends along the main face of the varistor 11, which limits the space requirement and also provides a thermal connection by convection or radiation. But the bimetallic strip 17 is in thermal connection with the varistor 11 first and foremost by thermal conduction through the electrode 11a. When the temperature of the bimetallic strip 17 increases beyond a given threshold, the latter bends, thus causing a displacement of its upper end bearing the trigger bar 15 along the main face of the varistor 11. As a result, the trigger bar 15 actuates the triggering mechanism of the switchgear 2 when the protection module 1 and the switchgear 2 are coupled.

Figure 3 illustrates another embodiment of the actuating means 12 with a varistor. The heat-sensitive member is a bimetallic strip 18. In the non-deformed state by heating, the bimetallic strip 18 has the shape of a curved or prestressed strip when it is mounted in the box 1a. This is the form of the bimetallic strip 18 under normal operating conditions of the device. One end of the bimetal 18 is attached to a connection electrode 11a of the varistor 11 which electrode 11a projects from a main face of the varistor 11 as described for the embodiment of FIG. 2. As can be seen, the varistor 11 has two other electrodes 1 lb, ie for connection to the terminals M9, MlO of the protection module 1.

The opposite end 18a of the bimetallic strip 18 bears against the end of an arm 18b. The arm 18b is pivotally mounted about an axis perpendicular to the main surface of the varistor 1 1, ie a horizontal axis in the representation of Figure 3. The arm 18b carries the trip bar 15. The possible movements of the trigger bar 15, depending on the deformation of the bimetallic strip 18, are also along the main face of the varistor 11, as indicated by the arrows F and G. In case of deformation due to the rise of its temperature , the bimetallic strip 18 tends to open, in other words its end 18a moves downwards in FIG. 3, and thus causes the arm 18b to rotate in the direction of the arrow F. The displacement of the bimetallic strip 17 or 18 along the main face of the varistor 11 in the embodiments of FIGS. 2 and 3 is also advantageous from the point of view of the size of the device.

FIG. 4 illustrates yet another embodiment of the actuating means 12 used in the device illustrated in FIGS. 5 and 6. The actuating means 12 comprise a bimetallic strip 19 having a parallelepipedal plate shape in an undistorted state . The bimetal 19 is fixed in an end region - in this case, in its upper part - on a main face of the varistor 11. More specifically, the bimetallic strip 19 is fixed on an electrode of the varistor 11 arranged on its surface main. Fixing the bimetallic strip 19 to the electrode can be carried out by any appropriate means such as by riveting holes 19a in the bimetallic strip 19. Here again, the bimetallic strip 19 is in thermal connection with the varistor 11 essentially by conduction between the bimetallic strip 19 and the electrode of the varistor, but also by convection and radiation. Under the effect of the temperature, the bimetallic strip 19 deforms in the part opposite to the end region by which it is fixed on the varistor 11.

The movement generated by the bimetallic strip 19 due to its deformation, is transmitted in this case to the trigger mechanism of the switchgear 2 through a rocker mechanism. More particularly, it is a monobloc rocker mechanism. A portion of the rocker forms a mast 21 pivotally mounted in the housing 1a. The lower and upper ends of the mast 21 are housed in bearings 21a shown in Figures 5 and 6. The trigger bar 15 is arranged on the mast 21 and extends in a longitudinal direction substantially orthogonal to the axis of rotation 21 of the mast 21. Similar to the embodiment of Figure 2, the trigger bar 15 protrudes out of the casing 1a through a window thereof and enters a window 16 of the housing 2a to cooperate with the mechanism of triggering of the breaking device 2, when the protection module 1 and the breaking device 2 are assembled. The connection between the lower and upper ends of the mast 21 and the bearings 21a may be purely a pivot or alternatively a sliding pivot, especially if the trip mechanism of the circuit breaker requires a combined movement of the trigger bar 15 in pivoting and translation during of its actuation. The mast 21 further comprises a rigid pallet 22 whose extension plane containing the axis of rotation J is substantially orthogonal to the longitudinal direction of the trigger bar 15. The end portion of the bimetal 19 which is at the opposite of its fixing region on the varistor 11 - in this case, the lower part - is located at the pallet 22. In case of deformation of the bimetal 19, this end portion deviates from varistor 11 and exerts a force on the rigid pallet 22. This force exerts on a part of the rigid pallet 22 offset from the axis of rotation J, which has the effect of rotating the mast 21. The bimetallic strip 19 is for this purpose in mechanical contact and preferably in free support on the rigid pallet 22. The trigger bar 15 rotates about the axis J with the pivoting of the mast 21, which has the effect of operate the trigger mechanism of the switchgear 2.

The mast 21, the trip bar 15 and the rigid pallet 22 can be made in one piece, for example by injection of a synthetic material, which provides a saving in production and assembly.

The fact that the mast 21 rotates - because of the pivot connection or sliding pivot - is advantageous because the rotational guidance is simple to implement and particularly reliable in contrast to a guide in pure translation, particularly with respect to a piece of plastic material.

It is advantageous to provide a locking system for locking the actuating means 12 in the release position when they have caused the disconnection switch 8 to open in response to excessive heating of the protection component. In this way, a user can not reset the electric switchgear 2 with his reset lever.

In this embodiment, the locking system comprises an elastic tongue 23 integral with the rigid pallet 22. The resilient tongue 23 is for example an extension of reduced dimensions of the lower part of the rigid pallet 22. The dimensions of the elastic tongue 23 are chosen to give it a suitable elasticity given the material constituting the rigid pallet 22. Alternatively, the resilient tongue 23 is attached and fixed on the rigid pallet 22 by any appropriate means.

The locking system also comprises a fixed abutment integral with the housing having a first bearing surface 24 and a second bearing surface 25 for the resilient tongue 23. The latter is prestressed against the first bearing face 24 by imposing on it bending downwards when mounting the rocker in the casing la. Such an arrangement is shown in FIG. 5 and corresponds to a position of non-triggering of the trip bar 15, that is to say to a power supply of the protection module 1.

When an excessive leakage current is established across the varistor 11 at the end of its life, the thermal energy released by the varistor 11 causes sufficient heating of the bimetal 19 to cause it to deform. As mentioned above, by deforming, the lower end of the bimetallic strip 19 flexes and deviates from the varistor 1 1 by lifting the rigid pallet 22. The bimetal 19 pushes the mast 21 according to a rotational movement to its trigger position. The trip bar 15 then actuates the trigger mechanism of the disconnect switch 8 in the housing 2a. The protection module 1 is then isolated from the power supply. The rotation of the mast 21, on a stroke determined by the deformation of the bimetallic strip 19, also results in a rotational movement, the elastic tongue 23, which is positioned because of its elasticity on the second bearing surface 25. The second bearing face 25 is preferably adjacent and substantially perpendicular to the first bearing face 24. This second bearing face 25 serves as an abutment to the elastic tongue 23 as illustrated in Figure 6. By abutting against this second face of 25, the elastic tongue 23 prevents the mast 21 from pivoting in the opposite direction to return to its initial position shown in FIG. 5. This results in an irreversible positioning of the mast 21 in its triggering position of the breaking device 2, even if after cooling the bimetallic strip 19 returned to its initial position before deformation. The design of the fixed abutment and the elastic tongue 23 take into account, where appropriate, the translational displacement component of the mast 21 in the case where the connection between the mast 21 and the bearings 21a is a sliding pivot intended to allow the movement bar 15 to follow a path imposed by the tripping mechanism of the circuit breaker, requiring a combined displacement in rotation and in translation of the trip bar 15.

The irreversible positioning of the mast 21 in its release position is obtained thanks to the intrinsic restoring force of the elastic tongue 23, bringing said tongue upwards in a position abutting against the second bearing face 25. the trip bar 15 remains in its trigger position, the switchgear 2 can not be reset using a manual or automatic control. The user is then informed, at least visually, by the tripping position of the operating lever of the circuit breaker, of a poor operating state of the protection module 1. An unsuccessful reset attempt gives the user otherwise. sensory information and more particularly tactile, indicating that the protection module is not operational.

According to a preferred embodiment, the thermosensitive member and more particularly the bimetallic strip 19, has a bistable deformation property, conferring on it a stable configuration that is not deformed in the absence of a heating of the varistor 11, as well as a configuration stable distorted in response to a given heating of the varistor 11.

The bistable character of the thermosensitive member, and in particular bimetal, is advantageous because of both the accuracy of the temperature at which it is deforms and the brutal nature of its deformation as a function of temperature while the deformation of a conventional bimetallic, as well as a heat shrinkable element, is progressive and less precise, may sometimes require adjustment means to tare.

Such a bistable bimetallic strip 19 may advantageously itself provide for the locking of the actuating means 12 in the release position when they have caused the opening of the disconnector switch 8. The locking system formed by the tab elastic 23 and the bearing face 25 forming a stop can be omitted in this case. For this purpose, the constituent material of the bimetallic strip 19 can be chosen so that its deformation cycle as a function of temperature exhibits a hysteresis. More precisely, the transition from the undeformed conformation to the deformed configuration takes place at a temperature greater than the ambient or normal operating temperature, preferably between 100 ^° C. and 180 ^° C. and particularly preferably between 135 ° C. and 14O ⁰ C, while the return of the deformed conformation to the undeformed configuration can take place only at a temperature well below room temperature and preferably between -20 ^° C. and -40 ^° C. Thus, the bimetallic strip 19 remains in the deformed state despite a return to ambient temperature, and therefore the bimetallic strip 19 maintains the mast 21 in the trigger position of the switchgear 2. The appropriate transition temperatures can be obtained by prestressing state induced by specific shaping of the bimetallic strip 19.

However, it is however possible to ensure the locking of the actuating means 12 other than by the hysteresis bistable character of the thermosensitive member, in particular by the locking system formed by the elastic tongue 23 and the bearing face 25 forming stop.

A locking system having the same function can also be provided in the embodiments of Figures 2 and 3. For the case of Figure 2, a stop - not shown - retractable by pivoting or by its elasticity, can be arranged in the housing la to cooperate with the trigger bar 15 or an upper end portion of the bimetallic strip 17. The trigger bar 15 or the end portion of the bimetallic strip 17 pushes the stop and passes beyond the stop in case of deformation of the bimetallic strip 17. But in reverse movement, the trip bar 15 or the end portion of the bimetallic strip 17 rests against the pivoting stop which is locked in this direction on a fixed part of the housing to prevent the return of the bimetallic strip 17 In the case of Figure 3, a pawl system may be provided on the axis of rotation I to prevent pivoting backwards - in the direction of the arrow G - from the bottom 18b. FIGS. 10 to 14 illustrate another embodiment which constitutes an alternative to that which has just been described in relation with FIGS. 4 to 6. FIG. 14 is an overall view of the protection module 1 mechanically coupled to a cutting device 2 by two pieces of clipping 100 (one being at the back not visible). FIG. 10 illustrates the actuating means 12 and the varistor 11 without representing the rest of the overvoltage protection device or the associated switching device. Figure 11 illustrates the protection module 1 mechanically coupled to the switchgear 2 which has its own housing 2a. The description made of the switchgear 2 in the context of the embodiment of FIGS. 4 to 6 applies similarly to this embodiment. In the illustrated example, it is a conventional magnetic or magnetothermic circuit breaker. In this embodiment, the casing 1a of the protection module 1 is made of two shells which are assembled, but the shell remote from the cut-off device 2 is not shown to show the arrangement of the components inside the casing. casing the.

Similarly to the embodiment of Figures 4 to 6, the actuating means 12 comprise a bimetallic 50. The shape of the bimetallic strip 50 is rectangular, except at its free end which is trapezoidal. The description made of the bimetallic strip 19 as regards its mechanical fixing and its operation - in particular under the effect of the heat which is communicated to it by the varistor 11 - in the context of the embodiment of FIGS. 4 to 6 is also applicable to this mode. realization and will not be repeated here.

Figure 12 shows the protection module 1 without the switchgear 2, but again with the same shell not shown to show the components of the protection device. In FIG. 12, the protection module 1 is represented in the non-tripped state, in other words when the bimetallic strip 50 has not yet caused the tripping apparatus 2 to be tripped. FIG. 13 is similar to FIG. , but on a smaller scale and represents the protection device in the triggered state, that is to say when the bimetallic strip 50 has triggered the breaking device 2 because of its deformation under the effect of the increase of its temperature beyond a given threshold. In FIGS. 12 and 13, the varistor 11 is also not shown in order to make visible the mechanism transmitting the movement of the bimetallic strip 50 to the cut-off device 2. On the other hand, it is visible thereon the electrode 51 of FIG. the varistor 50 on which the electrode is fixed by riveting 51a the varistor 50 through the holes 50a visible in Figure 10.

As in the embodiment of FIGS. 4 to 6, the actuating means 12 also comprise a mechanism for transmitting the displacement of the free end 50b of the bimetal 50 - due to its deformation under the effect of the increase of its temperature - to the triggering mechanism of the breaking device 2. But this mechanism is different from that of the embodiment of FIGS. 4 to 6. It is particularly visible in FIGS. 10, 12 and 13 whereas it is not visible in FIG. 11 because it is placed between the varistor 50 and the breaking device 2.

This mechanism comprises a pallet 52 mounted pivotally or tilting in the housing la, which is realized in the example illustrated by the fact that the pallet 52 has two opposite arms 52b and 52c whose ends are each received in a housing formed in a respective projection 53a, 53b coming from material by molding the casing la. The two arms 52b and 52c therefore define a pivoting or tilting axis for the pallet 52. Furthermore, the pallet 52 comprises an arm 52a offset radially with respect to the tilting axis. The arm 52a is placed at the free end 50b of the bimetallic strip 50 so that the free end 50b comes to urge the arm 52a in the event of deformation of the bimetallic strip 50 as a result of the latter being heated.

The pallet 52 comprises a support lug 52d which is provided to come into axial abutment against an abutment surface 54 arranged on the housing 1a. In the example shown, the abutment surface 54 is formed on a protrusion coming from material by molding the housing 1a. The pallet 52 is resiliently biased along the axis of pivoting or tilting of the pallet 52 to constrain the bearing lug 52d against the abutment surface 54. In this case, the pallet 52 is resiliently biased by a coil spring 55 placed around the arm 52b of the pallet 52 and which bears at one end on the projection 53b of the housing 1a and at its other end on the pallet 52.

The pallet 52 also comprises a notch 52e into which the free end of a trigger arm 56 is inserted which is pivotally mounted in the casing 1a by its other end. In the example illustrated, the trigger 56 is pivotally mounted about an axis 57 coming from material by molding the housing 1a. At the free end of the trigger arm 56 is arranged the trigger bar 15 which is provided to cooperate with the trigger mechanism of the switchgear 2 protruding out of the housing 1a through a window (not shown) provided in this last.

In normal operation, the protection module 1 is in the state shown in FIG. 12. When the leakage current of the varistor 11 increases abnormally and causes a large heating of the varistor 11, this heating causes a temperature increase bimetallic 50 sufficient to cause its deformation, which has the effect of moving its end 50b away from the varistor 1 1. The end 50b bimetallic 50 then presses on the arm 52a of the pallet 52, which has the effect of pivoting or tilting around its axis of pivoting or tilting. This pivoting or tilting has the effect of disengaging the bearing lug 52d from the abutment surface 54. Under the effect of the elastic bias to which it is subjected, namely by the spring 55 in our example, the pallet 52 is then moved along the axis of pivoting or tilting until the pallet 52 comes with a bearing edge 52f in abutment against the projection 53a of the housing la. In its movement, the pallet 52 causes the trigger 56 to pivot about its axis 57. Therefore, the trigger bar 15 is moved, which has the effect of actuating the trigger mechanism of the switching device 2. Therefore, the varistor 11 is disconnected from the power supply lines of the installation. This situation is represented in FIG. 13 in which it can be seen that the reset lever 2b of the circuit breaker is lowered, contrary to FIG. 12.

After triggering the switchgear 2 by the actuating means 12, it is not possible for a user to manually reset the switchgear with its reset lever 2b. Indeed, the trip bar 15 is held in the trigger position due to the elastic biasing of the pallet 2 against the projection 53a of the housing la.

FIGS. 15 and 16 illustrate a variant of the protection module 1 described with reference to FIGS. 10 to 14. The external appearance of the protection module 1 with its associated switching device 2 is identical to that illustrated in FIG. description made for the embodiment of Figures 10 to 14 is applicable to this variant, except for certain modifications of the actuating means 12 which will be described below. It also comprises a bimetallic strip 50 similar to that of the embodiment of FIGS. 10 to 14.

In FIG. 15, the protection module 1 is represented in the non-tripped state, that is to say when the bimetallic strip 50 has not yet caused the tripping apparatus 2 to be tripped. FIG. 16 is similar to FIG. , but represents the protection module 1 in the triggered state, in other words when the bimetallic strip 50 has triggered the associated switchgear device 2 due to its deformation under the effect of the increase of its temperature above beyond a given threshold. In FIGS. 15 and 16, the varistor 11 is also not shown in order to make visible the mechanism transmitting the movement of the bimetallic strip 50 to the switching device 2. The varistor 11 is arranged in the box 1a in a similar manner in the embodiment of Figures 10 to 14.

The actuating means 12 comprise a rod 58 which is articulated at one end 58b to the housing 1a. In the example shown, the rod 58 has a hook shape at its end 58b which engages in a through passage managed in a projection 59 which can come from material by molding the housing la. The rod is further inserted into a groove defined by two projections 60 which can also be made of material by molding the housing 1a.

The other end of the rod 58 passes at the free end 50b of the bimetallic strip 50. This end of the rod 58 has a return 58a passing from the opposite side of the bimetallic strip 50. In this way, the rod 58 is bonded - with in this case - at the end 50b of the bimetallic strip 50. The paddle 52 presents modifications with respect to the case of the embodiment of FIGS. 10 to 14. In this embodiment, the paddle 52 is not pivotally mounted. or tilting, but moves only laterally, that is to say in the direction of the axis defined by the arms 52b and 52c by which the pallet is held in the projections 53b and 53c of the housing la. The pallet 52 is biased elastically in the direction of the axis defined by the arms 52b and 52c, for example by a helical spring 55 as in the case of the embodiment of FIGS. 10 to 14. In the normal operating position, the pallet 52 is not in abutment against the projection 53a of the housing la, but against a recess 58c of the rod 58. It is therefore the rod 58 which retains in axial position the pallet 52. This situation is visible in Figure 15. Moreover, as in the embodiment of FIGS. 10 to 14, the pallet 52 has a notch 52 which cooperates with a lever 56 carrying the trigger bar 15.

When the leakage current of the varistor 11 increases abnormally and causes significant heating of the varistor 11, this heating causes an increase in temperature of the bimetallic 50 sufficient to cause its deformation, which has the effect of moving its end 50b. In contrast to the embodiment of FIGS. 10 to 14, the deformation of the bimetallic strip 50 brings the end 50b closer to the varistor 1 1. The end 50b of the bimetallic strip 50 then raises the corresponding end of the bead wire 58, which has the effect of clearing the pallet 52 of the recess 58b of the rod 58. As a result, the pallet 58 is no longer held axially by the rod 58. Under the effect of the elastic bias to which it is subjected, namely by the spring 55 in our example, the pallet 58 then moves laterally until the bearing surface 52f of the pallet 52 abuts against the projection 53a of the housing la. In its movement, the pallet 52 causes the trigger 56 to pivot about its axis 57. Therefore, the trigger bar 15 is moved, which has the effect of actuating the trigger mechanism of the switching device 2. Consequently, the varistor 11 is disconnected from the power supply lines of the installation. After triggering the switchgear 2 by the actuating means 12, it is not possible for a user to manually reset the switchgear with its reset lever 2b. Indeed, the trip bar 15 is held in the trigger position due to the elastic biasing of the pallet 2 against the projection 53a of the housing la.

In these different embodiments using a bimetallic strip as a thermosensitive member, the bimetal has a purely thermomechanical operation. In other words, the bimetal is not traversed by a current to warm up - and thus does not itself ensure the routing of the electric current to the protective component, although a bimetal has an inherently conductive character - and there is also no auxiliary thermoelectric circuit bimetal specifically intended to heat the bimetal by conversion into current heat - for example current flowing through the protective component - such as turns surrounding the bimetal to heat it by Joule effect.

Indeed, in order to monitor the temperature that can reach the protective component, the bimetal advantageously allows to ensure the direct detection by the thermal bond. It would be possible to use it also as a conductor in the electrical circuit, but this has the disadvantage of having to take into account its resistive nature which leads to the heating in addition of warming provided by the thermal connection with the protection component. In addition, it avoids undesirable current loop effects, which could lead to the generation of mechanical forces damaging to the reliability and operation of the device.

For the same reasons, it is preferable not to provide a bimetallic auxiliary thermoelectric circuit intended specifically for heating the bimetal by converting the current flowing through the protection component into heat. Indeed, this has the disadvantage of being an indirect detection of temperature and is ultimately more complex and more expensive to implement. The design of the device is not only simplified, but detection is also particularly reliable when heating bimetallic is exclusively provided by the thermal link.

In general, the fact of resorting to a thermosensitive member having a purely thermomechanical operation is advantageous for these same reasons.

FIG. 7 represents a fourth embodiment of the functional part of a protection module according to the invention. In this case, the thermosensitive member consists of a heat-shrinkable bar 20. This may be made of any suitable heat-shrinkable material, which may be chosen for example from a polyolefin, a fluoropolymer such as PVC, FEP, PTFE, Kynar And PVDF, and a chlorinated polyolefin such as neoprene. The heat-shrinkable bar 20 is fixed by an end 20a in the housing la. The actuating means 12 also comprise a lever 30 pivotally mounted in the housing 1a, for example by one of its ends 30a. The other end of the lever 30 carries the trigger bar 15 intended to cooperate with the trigger mechanism of the switchgear 2. The heat-shrinkable bar 20 is connected to the lever 30 preferably by a pivot connection. Under the effect of increasing its temperature beyond a given threshold, the bar 20 retracts and thus causes a pivoting of the lever 30. As a result, the trigger bar 15 actuates the triggering mechanism. 2. The heat-shrinkable bar 20 advantageously provides the locking to block the actuating means 12 in the release position when they have caused the opening of the disconnector switch 8. Indeed, the bar heat-shrinkable 20 no longer returns to its original conformation in the event of cooling due to the very nature of heat-shrinkable materials. The heat-shrinkable bar 20 may be replaced by a heat-shrinkable element having any other suitable shape.

Figures 8a and 8b show a fifth embodiment of the functional part of a protection module. In this embodiment, the thermosensitive member is a deformable capsule 40 filled with a fluid causing the deformation of the capsule according to its temperature. Preferably, the deformation of the capsule 40 - which serves to actuate the trigger mechanism of the circuit breaker

- is caused by the vaporization of the fluid, which provides a substantially bistable deformation property. The capsule 40 is arranged on a main face of the varistor 11. Figures 8a and 9a show the capsule 40 at room temperature, which corresponds to the normal operation of the device. In case of excessive heating of the varistor 11, the fluid contained in the capsule 40 vaporizes by reaching the latent heat of vaporization and the capsule 40 inflates accordingly, as shown in Figures 8b and 9b. The capsule 40 then acts on a mechanism - symbolized by the reference 41 - transmitting a movement to a trigger bar which cooperates with the trigger mechanism of the switching device 2 to actuate it. The mechanism 41 may for example be the rocker 15, 21, 22, 23 of Figure 4 in which case the capsule 40 and the rocker are arranged so that the capsule 40 acts on the pallet 22 in case of swelling to cause the pivoting of the mast 21. Similarly, the mechanism 41 may be that of the embodiments of Figures 10 to 14 which includes the pallet 52 and the trigger 56 or Figures 15 and 16 including the pallet 52, the rod 58 and the trigger 56. The capsule 40

- or at least its deformable face - can be made of copper and is designed to be deformable, for example similarly to the capsules used in the devices pressure gauges such as barometers, manometers or aircraft altimeters. The fluid in the capsule 40 is preferably a refrigerant. It is chosen according to the desired vaporization temperature. It may be a hydrofluorocarbon (HFC) chosen for example from R14, R23, R125, R134a, R152a, R227, R404A, R407C, R410A, R413A, R417A, R507, R508B, Isceon® 59, Isceon® 89, Forane® 23 or Forane® FX 80. Again, there can be provided locking means of the mechanism 41 to prevent its return to the non-triggering position once past the trigger position of the switchgear 2 due to the dilation of the capsule 40.

In all the embodiments described, it is possible to also provide a thermal connection between the spark gap 13 and the thermosensitive member. It can also be a conduction bond, but it may be more simply a convection bond because of the confinement provided by the housing, or even by radiation.

An advantage of the invention lies in the fact that the locking means prevent the reset of the breaking device 2 from being reset only in the event of failure of the varistor 1 1 and not in case of a self-tripping of the 2. Thus, in the embodiment illustrated in Figure 1, the flow of a large fault current or a final failure of the spark gap 13 could cause activation of the circuit. 2. The locking means would not then oppose manipulation intended to rearm the cut-off device 2. However, in case of permanent and irreversible degradation of the varistor 11 or the spark gap 13, the persistence of the failure in this case of the short circuit, would lead to the instantaneous delivery of the switchgear 2 in its tripped state. The safety of all the protective components is thus ensured by the protection device according to the invention.

In addition, the user has a feedback to the extent that he knows that an unlocked reset lever of the cutoff device 2, but that instantly returns to its trigger position thus preventing rearming, corresponds to a final failure of the varistor 11 and / or the spark gap 13.

The protection device according to the invention thus makes it possible to guarantee the safety of the protection component, regardless of the failure mode of said protection component and without interrupting the service power supply.

The protection module 1 according to the invention has actuating means which also allow a particular movement return direct between the thermosensitive member and the trigger mechanism by means of a structure advantageously simple, compact and inexpensive.

In all of the described embodiments, the cut-off device 2 had only one cut-off contact. Alternatively, it may include two cut-off contacts through which the protection module is respectively connected to the phase and the neutral of the power supply.

In all the described embodiments, the protection module 1 and the switching device 2 have their respective housing. Alternatively, the protection module 1 and the switching device 2 can be integrated in a single housing. But the fact that the protection module 1 has its own housing advantageously allows it to be used with commercial standard breaking devices - such as magnetic or magnetothermic circuit breakers - having their own housing 2a and without any modification. In particular, the protection module can be associated - preferably removably - with any model of circuit breakers of a given range to use the one having the desired electrical characteristics, for example in consideration of the breaking capacity and curves desired operation in view of the intended application.

Whether the protection module has its own housing or is incorporated with the switchgear in a common housing, it is advantageous for this housing to be provided for mounting and dismounting on a conventional connection or connection rail.

In all of the embodiments described with FIGS. 2 to 9b, the thermosensitive member moves itself, because of its deformation, the mechanical member or bodies, including the trigger bar, which cooperate with the mechanism of triggering the switchgear 2 for the purpose of actuating it. Alternatively, it may be provided that the thermosensitive member causes due to its deformation a displacement of these mechanical members to actuate the trigger mechanism of the cut-off device 2, not by moving itself this or these mechanical members, but allowing, because of its deformation, their displacement under the effect of an elastic bias of this or these bodies against the deformable part of the thermosensitive element, as is the case in the embodiments Figures 10 to 16. It may be preferable that it is the thermosensitive member itself that moves this or these organs because it avoids having to provide means to solicit against the thermosensitive member. But it may be more advantageous that, as in the embodiments of Figures 10 to 16, the actuating force applied by the trigger 56 on the trigger mechanism of the cut-off device 2 is not provided by the bimetallic strip. 50 or all another thermosensitive member that could be used in place of the bimetallic strip 50, but by the separate elastic biasing means constituted in the examples illustrated by the spring 55. In this way, it is sufficient for the bimetallic strip 50, or more generally for the member thermosensitive used, to be able to provide sufficient effort to release the pallet 52 of its abutment 53a or 58c. This force may be significantly less than the force required to actuate the trigger mechanism of the switchgear 2, which is provided by the biasing means - the spring 55 in the illustrated examples - which are designed accordingly. Therefore, the operation of the protection module 1 is more reliable and the design of the thermosensitive member is simplified, or it allows the use of types of thermosensitive organs that can not provide sufficient effort to operate them - the trigger mechanism of the switchgear 2

The invention is further advantageous because the protection module 1 does not require any means of its own to isolate itself from the power supply, the switchgear 2 alone providing the electrical insulation of the protection components whatever the failure.

The invention is also advantageous because it uses a switchgear which in itself has one or more electrical contacts used to cut the electrical circuit in which the device is inserted, and whose contact force, as well as the force applied to them to open them is determined by a mechanism specific to the cut-off apparatus. The contact force and the opening force of the contacts are therefore independent of the elements outside the breaking device used for its actuation. In particular, the contact force and the opening force of the contacts are not dependent on the effort that the thermosensitive member can provide, unlike, for example, bimetallic strip in the devices described in WO 2004/064213.

Depending on the implementation chosen, the invention allows a reliable use of security with a reduced number of components, a simple and compact construction, quick and easy assembly and disassembly on a connection or connection rail, a control easy operation of the operating state with a visual and sensory feedback on its operating state, and this without causing unavailability of the power supply network in the event of failure of the protective device

Of course, the present invention is not limited to the examples and embodiments described and shown, but it is capable of numerous variants accessible to those skilled in the art.

Claims

An overvoltage protection device, comprising: at least one overvoltage protection component (11; 13);

a thermosensitive member (17; 18; 19; 20; 40; 50) capable of deforming in dependence on its temperature; a thermal connection between the at least one protective component and the thermosensitive member; and

at least one mechanical member (15; 18b; 21; 30; 52,56; 52,56,58) for cooperating with the thermosensitive member and adapted to cooperate with a triggering system of an electrical switching device (2 ); in which the thermosensitive member and the at least one mechanical member are arranged so that, when the thermosensitive member exceeds a given temperature threshold, the thermosensitive member causes, due to its deformation, a displacement of said at least one mechanical member capable of to actuate the triggering system of the electric switchgear.

2. Device according to claim 1, wherein the thermosensitive member and the at least one mechanical member are arranged so that, when the thermosensitive member exceeds a given temperature threshold, the thermosensitive member moves because of its deformation said at least one mechanical member for actuating the triggering system of the electric switchgear.

3. Device according to claim 1 or 2, wherein the thermosensitive member is selected from the group consisting of: a bimetallic strip (17; 18; 19), a heat-shrinkable element (20) and a deformable capsule (40) filled with a fluid causing deformation of the capsule when the fluid exceeds said given temperature threshold, the fluid is preferably a refrigerant.

4. Device according to any one of claims 1 to 3, wherein the thermosensitive member (19) has a bistable deformation property conferring a stable configuration undeformed until its temperature does not exceed the given temperature threshold, and a stable configuration deformed when its temperature exceeds the given temperature threshold.

5. Device according to any one of claims 1 to 4, wherein said at least one mechanical member (15, 21, 22) is an element made of a single piece through which the heat-sensitive element is able to actuate, due to its deformation, the trigger system of the cut-off device.

6. Device according to any one of claims 1 to 5, wherein said at least one member comprises a mast member (21) pivotally mounted about an axis of rotation (J) and on which mast is arranged: a bar triggering circuit (15) adapted to cooperate with the triggering system of the switchgear, said trip bar extending in a direction substantially orthogonal to the axis of rotation of the mast; and a rigid pallet (22) radially offset relative to the axis of rotation of the mast, wherein said pallet is arranged so that the thermosensitive member under the effect of its deformation exerts a force on said pallet to rotate the mast .

7. Device according to any one of claims 1 to 4, wherein said at least one mechanical member comprises: a first member (52) movably mounted; and

- A second member (56) movably mounted on which is arranged a trigger bar (15) provided to cooperate with the trigger system of the switchgear; wherein: the first member is held in a first position by resilient bias (55) against a stop (53a); the thermosensitive member (50) is arranged to cause, due to its deformation, the disengagement of the first member (52) from the stop (53a) when the thermosensitive member exceeds said given temperature threshold, the disengagement of the first member from the stop causing the first member (52) to move beyond the stop by resilient biasing; and the second member (56) is coupled to the first member so that said displacement of the first member causes a displacement of the second member adapted to actuate the trigger system of the switchgear.

8. Device according to claim 7, wherein: the first member (52) is pivotally mounted or tilting about an axis; and the thermosensitive member (50) is arranged to disengage the first member of the stop by pivoting or tilting the first member, said displacement of the first member (52) beyond the stop being a translational movement according to the pivoting or tilting axis of the first member.

9. Device according to claim 7, wherein said at least one mechanical member further comprises a third member (58), wherein: the stop is arranged on the third member; the thermosensitive member (50) is arranged to cause the first member of the stop to disengage by moving the third member.

10. Device according to claim 8 or 9, wherein the second member (56) is pivotally mounted.

11. Device according to any one of claims 1 to 10, further comprising a locking system (23, 24, 25) for locking said at least one mechanical member in an actuating position of the triggering system of the apparatus cutoff (2) when the thermosensitive member has caused due to its deformation a displacement of said at least one mechanical member capable of actuating the trigger system of the electric switchgear.

12. Device according to claim 11, wherein the locking system is provided by a bistable hysteresis deformation property of the thermosensitive member.

13. Device according to claim 11 or 12, wherein the locking system comprises: a fixed abutment having two adjacent bearing faces substantially orthogonal to each other (24, 25); and an elastic tongue (23) arranged on said at least one mechanical member; in which the abutment and the elastic tongue are arranged so that: the elastic tongue is prestressed against the first bearing face (24) when the thermosensitive member has not yet caused due to its deformation a displacement of said at least one mechanical member (15, 21); and the elastic tongue comes to be positioned irreversibly against the second bearing face (25) under the effect of the intrinsic restoring force of the elastic tongue, as soon as the thermosensitive member has caused due to its deformation a displacement of said at least one mechanical member (15, 21) capable of actuating the triggering system of the electric breaking device (2).

14. Device according to any one of claims 1 to 13, wherein the at least one protective component comprises a varistor (11) and optionally a spark gap (13).

15. Device according to any one of claims 1 to 14, wherein the thermosensitive member has a purely thermomechanical operation.

16. Device according to any one of claims 1 to 15, wherein the thermosensitive member is in thermal connection by conduction with the protective component, either by direct contact with a face of the protective component, or by means of an electrode of the thermosensitive member, the greater part of the thermosensitive member being disposed preferably adjacent to a main face of the protective component.

17. Device according to any one of claims 1 to 16, comprising a housing (la) housing the at least one protective component and the thermosensitive member, the housing having a window through which said at least one mechanical member makes protruding out of the housing to cooperate with the triggering system of the switchgear when the switchgear (2) is arranged contiguous to the housing.

18. Device according to any one of claims 1 to 17, comprising an electric switching device (2) having a triggering system, wherein: said at least one mechanical member is arranged to cooperate with the trigger system of the electric breaking device; and the thermosensitive member and the at least one mechanical member are arranged so that, when the thermosensitive member exceeds said given temperature threshold, the thermosensitive member causes, due to its deformation, said displacement of said at least one mechanical member, said at least one mechanical member actuating the triggering system of the electric switchgear under the effect of said movement.

Device according to claim 18, comprising: a first housing (2a) housing said switchgear (2); and a second housing (1a) housing the at least one protection component (11; 13) and the thermosensitive member (17; 18; 19; 20; 40); wherein: the first housing and the second housing are assembled, preferably removably; the first housing has a first window (16) providing access to the triggering system of the switchgear; and the second housing has a second window through which the at least one mechanical member (15) protrudes from the second housing and enters the first housing through the first window to cooperate with the trigger system of the switchgear .

20. Device according to claim 18 or 19, wherein the switchgear and the protection component are electrically connected so that the actuation of the triggering system of the switchgear (2) causes the interruption of the switchgear. power supply of the protection component (11; 13).

21. Device according to any one of claims 18 to 20, wherein the switching device is a magnetic circuit breaker or magnetothermic circuit breaker.