EP0987803A1 - Protection device for electric installations against alimentation disturbances - Google Patents

Abstract

The overvoltage protection mechanism is connected via a connector (22a,22b) and a lightning conductor (40a) ins connected in circuit. The second connection is connected to a conductor piece (400a) with a fusing connection (25a) maintaining a connector piece (27a) in position until an overvoltage when the connector piece disconnects.

Description

The present invention relates to protective devices electrical installations against supply disturbances.

These devices are commonly used to protect devices electrical and electronic against surges that can be transmitted by power supply networks. Such overvoltages can especially be generated by lightning strikes reaching power network infrastructures.

Protection devices (which will be designated in this text by DAF designation "lightning protection device") can be integrated into a switchboard controlling the supply of several electrical outlets, or be connected directly upstream of the device to be protected.

• d'une part, les DAF monoblocs comprenant dans un boítier unique :
• 
  une partie active du DAF (utilisant un ou plusieurs éléments de varistance ou d'éclateur à gaz par exemple),
• 
  des éléments de connectique permettant de relier la partie active au circuit à protéger et au circuit d'alimentation (typiquement en parallèle de ceux-ci),
• 
  et éventuellement un système de visualisation de défaut indiquant l'état du DAF et/ou un bornier de télésignalisation de l'état du DAF.
• d'autre part, les DAF modulaires composés :
• 
  d'une embase fixée sur le tableau et intégrant la connectique et un éventuel bornier de télésignalisation,
• 
  et d'une cartouche enfichable de manière amovible sur l'embase, intégrant la partie active et éventuellement le système de visualisation de défaut.

The DAF integrated into an electrical panel (panel DAF) thus protect a plurality of devices by draining overvoltages to the ground. Among the existing table DAFs, there are:

• on the one hand, the monoblock DAF comprising in a single housing:
• 
  an active part of the DAF (using one or more elements of varistor or gas spark gap for example),
• 
  connection elements making it possible to connect the active part to the circuit to be protected and to the supply circuit (typically in parallel with these),
• 
  and possibly a fault display system indicating the state of the DAF and / or a terminal block for remote signaling of the DAF state.
• on the other hand, the modular DAF composed:
• 
  a base fixed to the switchboard and incorporating the connectors and a possible remote signaling terminal block,
• 
  and a cartridge pluggable in a removable manner on the base, integrating the active part and possibly the fault display system.

Existing DAFs, whether of the monobloc or modular type, use means for connecting the pins of the elements of connectors (themselves in contact with the supply circuit and the circuit to be protected) to the active part of the DAF.

These means generally comprise a conductive part of connection, connected to a first pin of the connector elements and welded to a first terminal of the active part, the other terminal of which is directly connected to the second pin of the connector elements.

In such a configuration, the weld between the connecting piece and the first terminal of the active part thus ensures mechanical contact between these two elements, and consequently the closing of the circuit of electrical protection formed by the connection elements and the part active DAF.

In addition, the welding is carried out so that when the current flowing through the DAF exceeds predefined values and characteristics of the DAF, or when the active part which is nearby of the solder causes excessive heating when reaching the end of its life, the connection provided by said weld is undone (by rupture or fusion of the welding) to allow the two elements it connects to separate.

In existing devices, the connecting piece is generally subjected to a permanent mechanical stress, tending to separate it from the terminal of the active part to which it is welded.

So when excessive current or too prolonged use causes respectively the rupture or the fusion of the weld, the part of link deviates from the terminal of the active part and the protection circuit included in the DAF is open.

The permanent mechanical stress mentioned above may result elastic deformation before welding of the conductive part, as describes it for example the document EP 0 716 493 in the name of the Applicant.

Another known embodiment making it possible to implement this mechanical stress uses a spring. This embodiment is shown in Figure 1, which is a diagram showing the main subsets a DAF according to the state of the art.

The DAF of this scheme is modular, but its subsets significant with regard to the invention which will be described may also be integrated into a known type of one-piece DAF.

Referring to FIG. 1, the modular DAF 10 is shown, composed of a cartridge 100 which can be plugged into a base 150. The cartridge 100 includes a surge protection circuit 40 which can be of any known type using for example varistors. The circuit 40 is connected to two terminals 101 and 102 each placed on one side side of the cartridge.

The cartridge of this modular DAF also includes two pads 103 and 104 for plugging into two respective female connectors 151 and 152 of the base 150. The terminal 102 is directly connected to the pad 104 by a link 1020, while terminal 101 on the opposite side of the cartridge is connected to a first rigid and electrically conductive part 110.

The stud 103 is connected to a first end of a flexible braid 105 also conducting electricity, the other end of which is connected to a second rigid part or cursor 120. The cursor 120 is connected to the part rigid 110 by a conductive weld 130.

Solder 130 is a low temperature solder which melts under the effect of prolonged exposure to a temperature exceeding approximately 100 ° C. This weld has a double holding function mechanical slider 120 in contact with the rigid part 110, and current routing between the braid 105 and the terminal 101.

It is also possible, depending on the state of the art, to replace the solder 130 by a non-conductive hot-melt element having a adhesive function (which can be produced for example in wax) ensuring the mechanical holding function and melting under the same conditions thermal, associated with an electrically conductive element capable of ensuring a link between the part 110 and the cursor 120 as long as the element hot melt is in place, this electrically conductive connecting element being however automatically broken when the element is merged hot melt. This electrically conductive connecting element can be formed of one or more thin, electrically conductive embedded wires in the hot-melt element. The mechanical role of these wires is negligible, but said wires provide the electrical connection between the braid and terminal 10. The electrically conductive connecting element can also be consisting of conductive means external to the hot-melt element.

A spring 140 permanently requests the cursor 120 for the detach from the part 110. In the present embodiment, the spring is compressed between a fixed support (which here is integral with the base but can press on an integral part of the cartridge), and the cursor. The spring can also be placed in any other conventional configuration, and in particular exert a traction on the end of the cursor opposite to the base 150.

The base 150 comprises two pins 153 and 154 connected to the connectors 151 and 152 respectively. These two pins allow connect the supply circuit to the circuit to be protected via the base, which is intended to be permanently fixed to an electrical panel.

It is understood that when the cartridge 100 is inserted in the base 150, a protection circuit is established, which connects the spindle in series 153, the pad 103, the braid 105, the cursor 120 which is connected to the piece 110 by the solder 130, the terminal 101, the circuit 40, the terminal 102 and finally the pad 104 and pin 154.

A device of this type has a limited lifespan. Arriving at the end of life its components heat up, causing the fusion of the weld 130. The cursor then no longer linked to the cartridge 100 is pushed towards the up by the spring and moves to stop the supply of the line to be protected by opening the protection circuit, as well as visualization and possibly the command of the remote signaling of the state of said varistor.

The weld 130 can also be broken by a shock caused by the passage of an excessive current, which causes the same displacement cursor.

Modular surge arresters such as that described with reference to the Figure 1 only offer a binary display of the state of the active part, ie that said part is in working order or that it has reached its end of life.

• état normal,
• une des deux varistances est déconnectée - cartouche fonctionnant encore mais à changer,
• les deux varistances sont déconnectées - cartouche hors d'usage.

The Applicant has brought to the modular DAFs an improvement consisting in providing the cartridge with a second varistor constituting a "reserve", by means of which a user can view three states of the active part of the device:

• normal state,
• one of the two varistors is disconnected - cartridge still working but to be changed,
• the two varistors are disconnected - cartridge out of use.

This visualization of the disconnection of one of the two varistors (and approaching the end of life of the cartridge) provides a time to change the cartridge while keeping activates the protection of the electrical installation thanks to the varistor remaining in service. A reserve DAF cartridge is described in patent EP 0 716 493 in the name of the Claimant.

In addition, as a result of the standardization of the formats of the materials low voltage, existing DAFs generally have dimensions standardized to facilitate their integration into different tables (58 mm high in particular).

A drawback of DAFs of the type described with reference to the figure 1, whether modular or monobloc, is that the presence of the braid complicates the mounting of the device, requiring points of additional soldering or crimping which tend to weaken overall, and to increase the risk of breakdown.

Another drawback of DAFs of the type described with reference to Figure 1, linked to the standard format mentioned above, is that as a result of the presence of the braid which presents a non-negligible bulk, the cartridge circuits of standard format modular DAFs cannot contain only one varistor.

This limitation prohibits the integration of the reserve devices mentioned above, which require the use of two varistors mounted in parallel in the DAF cartridge. As a result, the intensity of the current that the DAF can flow to the ground is limited to a value of the order of 40 kA 8/20, which is insufficient for certain applications.

An object of the present invention is to make it possible to perform DAFs simple and reliable structure, not including a braid which would constitute a bulky and weakening element.

A second object of the invention is to make it possible to develop a DAF withdrawable according to the characteristic stated in the previous paragraph, in which the cartridge is capable of flowing a current to the ground intensity of the order of 65 kA 8/20, the geometry of the cartridge respecting standard dimensions requiring in particular a height of 58 mm.

To achieve these goals, the invention provides a protection device against overvoltages of electrical devices to which the device is connected via connection means comprising at least two connectors, the device also comprising a lightning protection cell including a first pole is directly connected to a first of said connectors, characterized in that that a second pole of the cell is connected to a first part conductive, in that the device also comprises a second part conductive directly connected to a second of said connectors and in that that the device also includes fusible link means for maintain a rigid cursor in electrical contact with said parts conductive in an operating position of the device, means being adapted to permanently urge the cursor to a position opening of the device in which said cursor is no longer in contact with the two conductive parts.

• lesdites pièces conductrices sont rigides ,
• la liaison fusible utilise une soudure à basse température dont le point de fusion est voisin de 100°C ,
• le dispositif est de type débrochable et comporte d'une part une embase destinée à être fixée sur un tableau électrique, et d'autre part une cartouche enfichable sur l'embase et comprenant la cellule parafoudre, les deux pièces conductrices ainsi que le curseur, des moyens de contact électrique étant prévus entre l'embase et la cartouche ,
• la cartouche comprend une deuxième cellule parafoudre dont un premier pôle est directement relié à un troisième desdits connecteurs, en ce que le deuxième pôle de la deuxième cellule est connecté à une troisième pièce conductrice, en ce que le dispositif comprend également une quatrième pièce conductrice directement reliée à un quatrième desdits connecteurs et en ce que le dispositif comprend également un deuxième curseur rigide assurant une liaison électrique fusible entre lesdites troisième et quatrième pièces conductrices dans une position de fonctionnement du dispositif, des moyens étant prévus pour solliciter en permanence le deuxième curseur vers une position dans laquelle ledit deuxième curseur n'est plus en contact avec les troisième et quatrième pièces conductrices ,
• les troisième et quatrième connecteur sont confondus avec les premier et deuxième connecteur, respectivement ,
• le dispositif comporte des moyens mécaniques de visualisation de l'état de chacune des cellules parafoudres ,
• les moyens de visualisation comportent des doigts aptes à coopérer avec une pièce mobile du dispositif,
• les moyens de visualisation sont adaptés pour distinguer les cas où :
• (a) les deux varistances sont en service,
• (b) l'une des deux varistances est déconnectée,
• (c) les deux varistances sont déconnectées ,
• la hauteur entre d'une part un point de contact de l'embase avec le tableau électrique et d'autre part l'extrémité de la cartouche se trouvant à l'aplomb dudit point de contact lorsque la cartouche est enfichée sur l'embase n'excède pas 58 millimètres,
• il est prévu des moyens de télésignalisation de l'état de la cartouche,
• les moyens de contact électrique entre l'embase et la cartouche comprennent des éléments dont chacun comporte au moins deux branches, la forme des branches de chaque élément étant telle que la circulation d'un courant dans lesdites branches engendre une force électrodynamique tendant à écarter les branches ,
• lesdits éléments sont des éléments souples ou rigides en forme générale de « U »,
  • chacun desdits éléments comporte deux branches opposées situées entre un moyen de connexion de l'embase et un moyen de connexion de la cartouche,
    • la cartouche comprend deux circuits de protection contre les surtensions et l'embase comprend un interrupteur unique à deux positions, actionné par des éléments de signalisation de l'état respectif des deux circuits de protection, une première position de l'interrupteur correspondant à un état du dispositif dans lequel les deux circuits de protection sont actifs, la deuxième position de l'interrupteur correspondant à l'un des états suivants du dispositif:
    • un des deux circuits de protection hors service,
    • les deux circuits de protection hors service,
    • absence de cartouche dans le dispositif,
• lesdits éléments de signalisation sont des picots saillants hors d'une face de la cartouche se trouvant au contact de l'embase lorsque la cartouche est enfichée dans l'embase,
• chaque picot est maintenu en position saillante hors du boítier par une liaison fusible respective, ladite liaison fusible libérant le picot lui correspondant lors de l'arrivée en fin de vie du circuit de protection qu'elle maintient, un ressort associé au picot escamotant alors ledit picot dans la cartouche,
• l'embase comprend une pièce dont une première face est en appui sur l'interrupteur, les éléments de signalisation étant aptes à venir en appui sur une deuxième face opposée de ladite pièce,
• ladite pièce de l'embase est apte à basculer sélectivement autour de chacun des deux axes de ladite première face perpendiculaires à une ligne joignant les axes longitudinaux respectifs des deux éléments de signalisation et passant par les deux points de contact respectifs de ladite face avec lesdits éléments de signalisation,
• les projections des points d'appui sur ladite pièce des éléments de signalisation et de l'interrupteur dans le plan de ladite première face de ladite pièce sont alignées,
• dans ledit plan les projections des points d'appui des éléments de signalisation sont disposées symétriquement par rapport à la projection du point d'appui de l'interrupteur,
• l'interrupteur est précontraint mécaniquement pour solliciter ladite deuxième face de la pièce dans la direction opposée à la sollicitation des éléments de signalisation.

Preferred, but non-limiting aspects of the device according to the invention are the following:

• said conductive parts are rigid,
• the fuse link uses a low temperature solder whose melting point is close to 100 ° C,
• the device is of the withdrawable type and comprises on the one hand a base intended to be fixed on an electrical panel, and on the other hand a cartridge pluggable on the base and comprising the arrester cell, the two conductive parts as well as the cursor, electrical contact means being provided between the base and the cartridge,
• the cartridge comprises a second surge arrester cell, a first pole of which is directly connected to a third of said connectors, in that the second pole of the second cell is connected to a third conductive part, in that the device also comprises a fourth conductive part directly connected to a fourth of said connectors and in that the device also comprises a second rigid cursor ensuring a fusible electrical connection between said third and fourth conductive parts in an operating position of the device, means being provided for permanently urging the second cursor towards a position in which said second cursor is no longer in contact with the third and fourth conductive parts,
• the third and fourth connectors are merged with the first and second connectors, respectively,
• the device comprises mechanical means for displaying the state of each of the surge arresters,
• the display means include fingers capable of cooperating with a moving part of the device,
• the display means are adapted to distinguish the cases where:
• (a) both varistors are in service,
• (b) one of the two varistors is disconnected,
• (c) the two varistors are disconnected,
• the height between on the one hand a point of contact of the base with the electrical panel and on the other hand the end of the cartridge being in line with said point of contact when the cartridge is inserted on the base n '' does not exceed 58 millimeters,
• means are provided for remote signaling of the state of the cartridge,
• the means of electrical contact between the base and the cartridge comprise elements each of which comprises at least two branches, the shape of the branches of each element being such that the circulation of a current in said branches generates an electrodynamic force tending to spread the branches,
• said elements are flexible or rigid elements in the general shape of a "U",
  • each of said elements comprises two opposite branches situated between a connection means of the base and a connection means of the cartridge,
    • the cartridge comprises two overvoltage protection circuits and the base comprises a single switch with two positions, actuated by elements for signaling the respective state of the two protection circuits, a first position of the switch corresponding to a state of the device in which the two protection circuits are active, the second position of the switch corresponding to one of the following states of the device:
    • one of the two protective circuits out of service,
    • the two protective circuits out of service,
    • no cartridge in the device,
• said signaling elements are protruding pins outside one face of the cartridge being in contact with the base when the cartridge is inserted in the base,
• each pin is held in the projecting position outside the housing by a respective fuse link, said fuse link releasing the pin corresponding to it when the end of life of the protection circuit which it maintains, a spring associated with the pin then retracting said pin in the cartridge,
• the base comprises a part, a first face of which bears on the switch, the signaling elements being capable of coming to bear on a second opposite face of said part,
• said part of the base is capable of tilting selectively around each of the two axes of said first face perpendicular to a line joining the respective longitudinal axes of the two signaling elements and passing through the two respective points of contact of said face with said elements signaling,
• the projections of the support points on said part of the signaling elements and of the switch in the plane of said first face of said part are aligned,
• in said plane, the projections of the support points of the signaling elements are arranged symmetrically with respect to the projection of the support point of the switch,
• the switch is mechanically prestressed to urge said second face of the part in the direction opposite to the urging of the signaling elements.

• la figure 1 est un schéma de principe d'un DAF selon l'état de la technique, dans un mode de réalisation où le DAF est débrochable,
• les figures 2a et 2b sont des schémas de type bloc-diagramme de deux variantes d'un DAF selon l'invention,
• la figure 3 est une vue en perspective d'une cartoüche de DAF débrochable selon l'invention,
• la figure 4 est une vue en perspective d'un mode de réalisation d'un DAF débrochable selon l'invention,
• les figures 5a à 5d sont des représentations schématiques des états possibles du circuit de la partie active d'un DAF selon l'invention,
• la figure 6 est une vue éclatée précisant la structure interne d'une cartouche de DAF selon l'invention,
• les figures 7a à 7f sont des schémas représentant les différents états du système de visualisation de défaut d'un DAF selon l'invention,
• la figure 8 est une représentation schématique en coupe verticale transversale des éléments permettant de commander un bornier de télésignalisation de l'état de la cartouche d'un DAF modulaire selon l'invention,
• les figures 9a à 9c sont des représentations en perspective d'une partie de ces éléments de commande, à trois étapes respectives de leur fonctionnement.

Other aspects, aims and advantages of the invention will become more apparent from the following description of a preferred embodiment thereof, given by way of example and made with reference to the appended drawings, in which:

• FIG. 1 is a block diagram of a DAF according to the state of the art, in an embodiment where the DAF is withdrawable,
• FIGS. 2a and 2b are block diagram diagrams of two variants of a DAF according to the invention,
• FIG. 3 is a perspective view of a withdrawable DAF cartridge according to the invention,
• FIG. 4 is a perspective view of an embodiment of a withdrawable DAF according to the invention,
• FIGS. 5a to 5d are schematic representations of the possible states of the circuit of the active part of a DAF according to the invention,
• FIG. 6 is an exploded view specifying the internal structure of a DAF cartridge according to the invention,
• FIGS. 7a to 7f are diagrams representing the different states of the fault display system of a DAF according to the invention,
• FIG. 8 is a schematic representation in transverse vertical section of the elements making it possible to control a terminal for remote signaling of the state of the cartridge of a modular DAF according to the invention,
• Figures 9a to 9c are perspective representations of part of these control elements, in three respective stages of their operation.

With reference to FIG. 2a, the principle of the structure has been represented. internal of a DAF according to the invention. The device shown in this figure is of modular type, but the principle of the invention is also applicable to monoblock DAFs.

The withdrawable cartridge of the DAF comprises an active part 40, connected via two terminals to pads 22 and 23 for plugging into a base such than that described with reference to Figure 1.

The principle of the invention is as we said applicable to DAF monoblocks; in this case the diagram of Figure 2a remains applicable, the elements 22 and 23 then corresponding to the connection pins with the circuit to protect.

The pad 22 is directly connected to a first conductive part rigid 24, which is located opposite a second rigid conductive part 26 fixed on a first terminal 260 of the active part. The two rooms 24 and 26 are fixed, and separated by a space sufficient to prevent passage current between them when said space is cleared. In a variant of the invention, the pad 22 and the conductive part 24 can also constitute a unique element.

A third rigid part 27, or slider, is mounted in translation of so as to be able to be engaged in the space separating parts 24 and 26 in a first position in which the cursor establishes a contact electric between the two rooms when said space is free.

A weld 25, of the type described with reference to FIG. 1, keeps the cursor in said first position and thus links electrically the pads 22 and 23, the second terminal of the active part which is not shown in the figure being directly connected to the stud 23.

As in the known device described with reference to Figure 1, the solder 25 can be replaced by a hot melt connection equivalent mechanical characteristics. In this case, it is not necessary to provide additional means to establish contact electric between parts 24 and 26, said contact being ensured by the cursor 27 in its first position.

A spring 28, one side of which is fixed to the end of the slider opposite to the solder 25, and the other side fixed to a fixed element of the cartridge not shown in the figure, is held in extension so as to stress permanently the cursor so that it leaves its first position described more up, and join a second position in which the cursor is no longer in contact with parts 24 and 26.

According to the invention and as shown in Figure 2b, the spring 28 can also be compressed between a fixed point 280 of the cartridge and a part 281 secured to the cursor. In this variant, the effect of the spring is the even on the cursor.

We understand that the result of the operation of this device is the same as that of the device known in FIG. 1. The essential difference between the two devices lies in the addition, in the device according to the invention, the cursor 120 which makes it possible to get rid of a braid conductive.

This arrangement is advantageous because it makes it possible to carry out a DAF or a DAF cartridge with a smaller footprint or, equivalent footprint, to integrate additional components, as we will see.

Referring now to Figure 3, a cartridge 30 of DAF modular, standard format which can contain according to the state of the art a single varistor, carries on its lower face 301 four studs 22a, 22b, 23a and 23b for plugging into a fixed socket.

The fact of having for the connection between the cartridge and the base of four studs instead of two thus authorizes, with equal cross-section of the studs, the passage of a current of higher intensity between the cartridge and the base.

The cartridge 30 according to the invention does not include a braid such that described with reference to Figure 1. This results in space saving which allows to house in the housing 300 of the cartridge two varistors intended for be connected in parallel between the phase wire on the one hand, and on the other hand the neutral or earth of an electrical installation, or between neutral and earth.

The two varistors are connected to the pads 22a and 23a on the one hand, and 22b and 23b on the other hand, respectively. Cartridge 30 includes also two pins 36a and 36b whose role will be explained later in this text, protruding out of the face 301 which is intended to be in contact with the base, the two pins being able to slide in the openings 360a and 360b of said face 301 of the housing 300 for a retraction in the housing.

To ensure the correct polarity of the cartridge connection on its base by an operator, the lower face 301 comprises also a key 35 intended to cooperate with an organ corresponding to the base. Figure 4 is a perspective view of the cartridge 30 and the corresponding base 400, which includes the coding 350.

Figure 4 also shows a variant of the invention, which consists in providing the base with a socket for the connection of a 410 module remote indication of the cartridge status. We will come back to the means to control this remote signaling.

Figures 5a to 5d show the four possible states of the two varistors, referenced here 40a and 40b. These two varistors, which are mounted as we said in parallel, are each associated individually to the disconnectors 25a and 25b, respectively. In practice, the disconnectors 25a and 25b are produced by the combination of the cursor 27 and a fuse link such as the solder 25 of FIG. 2.

Reference may be made to the text of patent EP 0 716 493 in the name of the Applicant for a detailed explanation of the circuit formed by the varistors and disconnectors, which correspond here respectively to active parts and to the fuses and cursor links of the device according to the invention.

Referring now to Figure 6, the housing generally paralepipedic 300 of the cartridge 30 contains two subsets identical, one of which will be described here.

The varistor 40a, which is located in the central part of the case, is connected by a first terminal to stud 23a for connection with a base, and by a second terminal 400a to a fuse link 25a which implements a weld as described above.

The welding of the link 25a maintains a cursor 27a leading electricity in contact with terminal 400a and connection pad 22a with a base, said cursor thus ensuring contact with the weld connection between the terminal and the stud.

A spring 28a is prestressed in compression, its lower end being linked to the cursor 27a above which the spring is located, and the other end of the spring pressing against a finger 60a secured to the cursor, finger that the spring tends to move away from the face 301 of the cartridge.

Inside the housing 300, the pin 36a, the link 25a, the terminal 400a and the spring 28a are arranged along a lateral face of the housing adjacent to the face 301. A direction I is defined with reference to this figure perpendicular to this lateral face.

Under the effect of its compression, the spring exerts a thrust constant, direction parallel to said lateral face of the housing and directed towards the face of the case opposite the base, on the finger 60a which urges its turn the cursor 27a aligned with the pin 36a and the spring 28a.

The constant thrust mentioned above thus tends to separate the said cursor of solder 25a, terminal 400a and stud 23a, which causes the opening of the circuit comprising the varistor 40a located between the studs 22a and 23a.

When now the weld 25a gives way, under the effect of the passage of a excessive current or overheating due to the end of life of the varistor, the spring 28a separates the cursor 27a from the solder 25a and drives the finger 60a rigidly secured to the cursor and aligned above it, towards the upper face of the housing which is opposite to the base.

We will now explain the second role of finger 60a, which intervenes also for signaling the state of varistor 26a.

The weld having given way and the finger 60a having moved away from it of the base, the finger acts on a witness 600 consisting of a pallet placed in the housing 300 against the face opposite the base, as we will explain it with reference to Figures 7a to 7c.

FIGS. 7a to 7c are diagrams of views in the direction I of FIG. 6, elements of the cartridge 30 in the three possible states of device according to the invention.

The face that the housing 300 presents in these views is that, lateral, against which the assemblies formed by a spike, a fusible link, a cursor, a spring and a finger secured to the cursor are installed.

Figures 7d to 7f are three schematic views of the witness 600 seen from the interior of the case 300, corresponding to the states of views 7a to 7c respectively.

With reference to FIG. 7a, the two identical and parallel fingers 60a and 60b, respectively attached to the sliders linked to the two varistors of the DAF, are at a distance from witness 600, the two links 25a and 25b being provided by the welds of the respective sliders.

Figure 7a shows the U-shaped section of control 600 which shows one side parallel to the wall of the housing located nearby and two lateral sections 600a and 600b located on the sides of this first face and protruding towards the inside of the housing 300.

The ends of the two fingers 60a and 60b which are turned towards the witness 600 define a beveled profile with two oblique ramps and opposite to the axis of the finger. The ends of the fingers 60a and 60b each defines a protruding V-shaped profile, the two slopes of each V being able to cooperate with the protruding sections of the witness 600 as we will explain.

In the position shown in Figure 7a, the two varistors of the device are connected and therefore the two fingers 60a and 60b secured respectively of the cursors linked to the two varistors are in a position far away from indicator 600. Indicator 600 then extends along the axis longitudinal of the face 302, opposite the base, near which it is located.

The width of the witness, defined by the distance between its two sections lateral 600a and 600b, is chosen less than the value of the center distance between the two fingers 60a and 60b.

Therefore, in the position shown in Figure 7a in which witness 600 is located in the middle of face 302, the sections protruding from the witness are opposite the ramp at the end of the finger 60a which is facing the finger 60b, and the ramp at the end of the finger 60b which faces the finger 60a, respectively.

The corresponding view 7d shows that the indicator 600, which is mounted at pivoting about an axis 620 which extends substantially parallel to the fingers 60a and 60b, is then in the middle of the face 302 of the case close to which it is implanted. An outside observer looking at this face 302 of the case 300 can then see through a window 610 of said face the position of the witness which completely obstructs orifice 610.

Witness 600 has an extended central portion 6000 extended by a second portion 6001, made of material with the portion 6000, located in its extension and of substantially smaller width. The indicator 600 also has two elastic lateral tabs 602a and 602b intended to come selectively to bear on the side walls of the case to stabilize the position of the witness, as we will explain.

In view 7b, the finger 60b has been moved by the spring which is linked to it following the rupture or the fusion of the corresponding weld. The ramp of this finger which is turned towards finger 60a then cooperates with the projecting section 600b of witness 600 to move one end of said witness, which rotates then around axis 620, as shown in Figure 7e.

In the position of FIG. 7e, the witness is kept in a angular position away from the median axis of the face 302 of the cartridge, on the one hand thanks to the cooperation of the finger 60b with the section 600b, and on the other hand to the elastic support on an internal side wall of the housing 300 of the lateral tab 602b of the witness, elastically deformable.

Thanks to the special geometry of witness 600 which is not constant width but has two symmetrical lateral recesses defining a narrower width near its end being in the region of window 610, an outside observer can view the state of the device. Indeed, in this position of the witness 600, the window 610 is only partially obstructed by witness 600 due to its position angular away from the median axis of the face 302.

When the second varistor in turn reaches its end of life, that the finger 60a is in turn driven towards the witness 600 by its spring respective, the ramp of the finger 60a remote from the finger 60b cooperates with a second projecting section 600a of the witness to further move said witness rotating in the same direction as before. An outside observer then visualizes through window 610 the state of the cartridge, the indicator 600 leaving the window completely cleared.

A user can therefore view the status of the cartridge at any time DAF according to the invention. We understand that since the two sections protruding 600a and 600b of the witness extend respectively opposite symmetrical inclined ramps of the two fingers 60a and 60b, and that the witness 600 is itself symmetrical, the operation of the device is the same regardless of the varistor arriving first at the end of life.

In fact, only the direction of rotation of the indicator 600 around the axis 620 varies depending on the varistor that is disconnected first. The the witness's movements and movements being symmetrical, the cartridge status reporting is independent of the identity of the first varistor to be disconnected.

If necessary, a description can be found in document EP 0 716 493 more detail of the operating principle of a DAF with two varistors forming a reserve.

The device according to the invention is particularly advantageous in that that it has characteristics of reliability and robustness due to the absence of a braid, the bonds of which are a factor of fragility.

In addition, the device according to the invention allows, as has been shown to integrate into a withdrawable DAF cartridge of reduced format two varistors operating according to a reserve system.

According to a characteristic of the invention not shown in the Figures, the means of contact of the base with the cartridge can include semi-rigid means conducting electricity, the section of which is in the shape of a "U" so as to define two branches placed opposite between a connector on the base and a connector on the cartridge, each branch being in contact with a respective connector.

This characteristic generates in said contact means a electrodynamic force tending to spread their branches, when the means contacts are crossed by a current. Said branches go under the action of this spreading force press against the connectors the base and the cartridge, ensuring the quality of the contact between these connectors.

This significantly reduces the risk of poor electrical contact between the connectors of the base and the cartridge, which can cause overheating, or even the appearance of electric arcs in the connection area between the base and the cartridge.

Referring again to Figure 6, we will now describe a second characteristic of the device according to the invention, independent in characteristics already described.

It was said that the cartridge sub-assemblies included a solder 25a connecting terminal 400a to a stud 22a.

This welding also makes it possible to maintain the cursor 27a in a space located between the terminal 400a and the stud 22a, so as to ensure the electrical contact between these two elements.

On the other hand, with varistor 40a is also associated the picot 36a projecting from the so-called lower face 301, through an opening in which it can slide longitudinally in a direction perpendicular to the plane of the face 301.

The subassembly also includes the spring 28a located at the inside of the case and substantially aligned with the pin 36a and the cursor 27a. It will be noted here that the spring 28a can also be prestressed in extension between a fixed point on the housing away from the base and the cursor, and act on it in the same way as described above.

The pin 36a is also integral with the cursor 27a so that when said cursor is held between terminal 400a and stud 22a by the solder 25a, the pin 36a protrudes from the face 301 of the housing in protruding from said face by a height H1.

The pin 36a, the slider 27a and its weld 25a as well as the spring 28a are arranged to be substantially aligned along the same face of the cartridge case 30.

In the case where the weld no longer holds the cursor (as a result the passage of a shock current causing the weld to break, or of the weld fusion following a prolonged heating of the varistor arriving at end of life), the spring 28a recalls the cursor and the pin towards the side of the cartridge opposite to the base, said pin then being retracted (partially or completely) in the cartridge.

The cartridge 30 also includes a second sub-assembly identical to the one just described, implementing a second spring, a second slider and a second pin 36b.

When one of the varistors reaches the end of life, the spike that is associated is therefore retracted into the cartridge 30. We will now explain the specific function of these pins.

When the two varistors of the DAF cartridge are operational, the welds respectively associated with the two varistors maintain the two pins 36a and 36b projecting from a height H1 outside the cartridge case.

When the cartridge is inserted on its base, the pins 36a and 36b penetrate into the respective orifices 46a and 46b of the base, shown in Figure 4.

Referring now to Figure 8, there is shown in section transverse vertical the cartridge 30 plugged into the base 400, the studs 22, 23 of connection not being shown on this sectional plane which contains the axes of the two pins 36a and 36b.

The base includes a part 29 comprising a plate rectangular 290 extending substantially parallel to the upper face of the base and a half-disc 291 perpendicular to the plate, one of which side forms an edge 292 with the diameter of the half-disc.

The half-disc 291, which is located in a housing complementary to the base, can pivot while remaining in the same plane, as well as move in translation towards the upper face of the base.

The pins 36a and 36b are shown projecting outside the cartridge. In this position, the two pins enter the base by the respective orifices 46a and 46b and are supported on the upper face of the plate 290, on either side of the axis of symmetry of the part 29 which is perpendicular to the edge of the part.

The center of the underside of the plate is also pressing a 295 microswitch button controlling the signal reversal all or nothing of a remote signaling circuit of the state of the device. The three support points on the two sides of the plate are aligned parallel to the edge of the part, creating no moment perpendicular to this edge on the part 29.

A spring not shown in the figure tends to lift in permanently push button 295.

In this position, the plate is therefore kept parallel to the face of the base by the equal pressures of the two pins pressing on the two sides of the upper face of the plate, which is also supported on pusher 295.

In addition, the plate has a pressure transmission function pimples to the pusher and presses itself on the top of the pusher, now this one in a so-called low position corresponding to the remote signaling of a device state in which the two varistors are operational.

When now one of the pins (for example the pin 36b) is retracted into the cartridge, due to the failure of the varistànce which associated with it, the plate is no longer subjected only to the pressure of the pin 36a on one side of its upper face, and at the opposite pressure from the microswitch 295, in the center of its underside.

These two forces cause the plate to pivot around from the axis parallel to the axis of symmetry of the plate and containing the point of contact of the wafer with the pin 36a.

The pusher 295 can then be lifted under the action of the spring which permanently requests it, up to a second so-called high position where said pushbutton controls the reversal of electrical signals to signal the fault varistor.

In FIG. 8, the retracted position of the pin 36b and the positions resulting for the tilted insert and the pusher are shown with dots.

Figures 9a to 9c schematically represent the positions possible of the pair of pins 36a and 36b of the part 29 and of the pusher 295 controlling the remote signaling signals of the state of the device.

In FIG. 9a, the two pins 36a and 36b project towards the bottom out of the cartridge, the two varistors associated respectively with these pins being in service.

In this configuration, the wafer 290 is maintained as we saw it perpendicular to the axes of the pins and the pusher 295 by the equal and diametrically opposite pressures of these two pins, and the said pusher is held down in said low position.

This low position of the pusher corresponds to the control of electrical signals remotely indicating that the two varistors of the device are in service.

In FIG. 9b, one of the two pins is retracted inside the cartridge case. In the case of FIG. 9b, it is the pin 36b which is retracted. However, the configuration described here is symmetrical and could apply to a situation in which the pin 36a is retracted and the pin 36b is projecting downwards.

In this configuration, the wafer 290 has, as we have seen pivoted around its point of contact with the pin 36a, and the pusher 295 is in the high position due to the stress of the spring associated with it.

In this high position, the pusher signals at a distance that one at least one of the device's two varistors is out of service.

In FIG. 9c, the two pins 36a and 36b are retracted. The wafer 290 thus finds a position parallel to its position in the figure 9a. The push-button 295 remains in this configuration in the high position and thus always signals the device fault remotely.

• dans le cas où les deux varistances du dispositif sont en état de marche, le minirupteur signale à distance l'état du dispositif,
• et le minirupteur signale également à distance un état de défaut correspondant soit au défaut d'une des deux varistances, soit au défaut des deux varistances ou encore à l'absence de cartouche sur l'embase. En effet, dans le cas où aucune cartouche n'est enfichée sur l'embase, la plaquette 290 n'est soumise qu'à la pression exercée par le poussoir 295 et ledit poussoir est en position haute.

The specific configuration described above for the remote signaling system of the state of a lightning protection device comprising two varistors is advantageous because it makes it possible to signal with a single microswitch the state of the device according to a binary mode (corresponding to a logic function "or"):

• if the two varistors of the device are in working order, the microswitch remotely signals the state of the device,
• and the microswitch also remotely signals a fault state corresponding either to the fault of one of the two varistors, or to the fault of the two varistors or to the absence of a cartridge on the base. Indeed, in the case where no cartridge is plugged into the base, the wafer 290 is only subjected to the pressure exerted by the pusher 295 and said pusher is in the high position.

In particular, when inserting a cartridge, the two of which varistors are in service in the base, the microswitch changes state in moving from its high position to its low position (indeed, part 290 is translated from its position illustrated in FIG. 9c to its position illustrated in the Figure 9a when installing a cartridge).

Such use of a single microswitch to report the condition of a device with two varistors makes it possible to reduce the complexity and the costs linked to the wiring between the microswitches and a remote signaling unit, compared to existing solutions in which a microswitch is associated with each varistor.

Claims (22)

Device overvoltage protection device (20) to which the device is connected via connection means comprising at least two connectors (22, 23, 22a, 23a, 22b, 23b), the device also comprising a lightning arrester (40, 40a, 40b) of which a first pole is directly connected to a first of said connectors (23, 23a, 23b), characterized in that a second pole (260) of the cell is connected to a first conductive part (26, 400a), in that the device also includes a second conductive part (24) directly connected to a second of said connectors (22, 22a, 22b) and in that the device also includes fusible link means (25, 25a, 25b) for maintaining a rigid cursor (27, 27a) in electrical contact with said conductive parts in an operating position of the device, means (28, 28a) being provided for permanently urging the cursor towards an open position of the device in which said cursor is no longer in contact with the two conductive parts. Device according to claim 1, characterized in that said conductive parts (26, 400a, 24) are rigid. Device according to claim 1 or 2, characterized in that the fuse link (25, 25a, 25b) uses a low temperature solder whose melting point is close to 100 ° C. Device according to one of the preceding claims, characterized in that it is of the withdrawable type and comprises on the one hand a base (400) intended to be fixed on an electrical panel, and on the other hand a cartridge (30) pluggable on the base and comprising the cell surge arrester, the two conductive parts as well as the cursor, means of electrical contact being provided between the base and the cartridge. Device according to the preceding claim, characterized in that that the cartridge comprises a second surge arrester cell (25b), one of which first pole is directly connected to a third (23b) of said connectors, in that the second pole of the second cell is connected to a third conductive part, in that the device also comprises a fourth conductive part directly connected to a fourth (22b) of said connectors and in that the device also includes a second rigid cursor ensuring a fusible electrical connection (25b) between said third and fourth conductive parts in a position of operation of the device, means being provided for requesting permanently the second cursor to a position in which said second cursor is no longer in contact with the third and fourth conductive parts. Device according to the preceding claim, characterized in that that the third and fourth connector are confused with the first and second connector, respectively. Device according to claim 5 or 6, characterized in that it comprises mechanical means (600, 610) for viewing the state of each of the surge arresters. Device according to the preceding claim, characterized in that that the display means comprise fingers (60a, 60b) capable of cooperate with a moving part (600) of the device. Device according to one of claims 7 or 8, characterized in that the display means are adapted to distinguish the cases where: the two varistors are in service, one of the two varistors is disconnected, the two varistors are disconnected. Device according to one of Claims 4 to 9, characterized in that that the height between on the one hand a point of contact of the base with the electrical panel and on the other hand the end of the cartridge being plumb with said contact point when the cartridge is plugged in the base does not exceed 58 millimeters. Device according to one of claims 4 to 10, characterized in what is provided for remote signaling means (410) of the state of the cartridge. Device according to one of claims 4 to 11, characterized in what the means of electrical contact between the base and the cartridge include elements, each of which has at least two branches, the shape of the branches of each element being such that the circulation of a current in said branches generates an electrodynamic force tending to spread the branches. Device according to the preceding claim, characterized in that that said elements are flexible or rigid elements in general form of "U". Device according to claim 13, characterized in that each of said elements has two opposite branches located between a connection means of the base and a connection means of the cartridge. Device according to one of Claims 4 to 14, characterized in that the cartridge (30) comprises two overvoltage protection circuits and in that the base (400) comprises a single switch (295) with two positions, actuated by elements (36a, 36b) for signaling the respective state of the two protection circuits, a first position of the switch (295) corresponding to a state of the device in which the two protection circuits are active, the second position of the switch corresponding to one of the following states of the device: one of the two protective circuits out of service, the two protective circuits out of service, no cartridge in the device. Device according to claim 15, characterized in that that said signal elements (36a, 36b) are protruding pins outside a face (301) of the cartridge (30) being in contact with the base (400) when the cartridge is inserted in the base. Device according to claim 16, characterized in that that each pin is held in the projecting position outside the housing by a respective fuse link (25a), said fuse link releasing the pin correspondent when the end of life of the protection circuit it maintains, a spring associated with the pin retracting said pin in the cartridge (30). Device according to one of claims 15 to 17, characterized in that the base (400) comprises a part (29), one of which first face is supported on the switch (295), the elements of signaling (36a, 36b) being able to come to bear on a second face opposite of said part (29). Device according to the preceding claim, characterized in that said part (29) of the base is able to tilt selectively around each of the two axes of said first face perpendicular to a line joining the respective longitudinal axes of the two elements of signaling and passing through the two respective contact points of said face with said signaling elements. Device according to claim 18 or 19, characterized in what the projections of the support points on said part (29) of the elements signaling (36a, 36b) and the switch (295) in the plane of said first face of said piece are aligned. Device according to the preceding claim, characterized in that in said plane the projections of the support points of the elements of signs are arranged symmetrically with respect to the projection of the switch support point. Device according to one of claims 18 to 21, characterized in that the switch is mechanically prestressed to urge said second face of the part (29) in the direction opposite to the stress signaling elements (36a, 36b).

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