EP2541578B1 - Electrical protection device comprising at least one cut-off module controlled by a control device with an electromagnetic coil - Google Patents

Description

The present invention relates to an electrical protection device comprising at least one cut-off module mounted on a mounting support, and an electromagnetic coil control device juxtaposed with one of the above-mentioned modules, each cut-off module comprising two contacts of which one is movable relative to the other between a first position in which the contacts are closed and allow the passage of current and an open position in which the current is interrupted between the contacts, and the aforesaid control device comprising an electromagnetic coil suitable to control the opening or closing of the contacts, the coil of the control device being located substantially opposite the (or) point (s) of contact of the contacts (or) module (s) cutoff, the axis said first the coil of the control device extending substantially perpendicular to the plane of attachment while the axis (the axes) of (the) module (s) cutoff s' tends (ent) substantially parallel to the fixing plane, said first axis extending substantially perpendicularly to the axis (the axis) said (s) second (s).

Electrical protection devices such as low-voltage circuit breakers allow in a manner known per se to interrupt the electrical current in an electrical circuit by separating the contacts so as to protect goods and people from the effects of short-circuit currents.

The present invention relates more particularly to the field of ultrafast type protection circuit breakers associated with electromagnetic auxiliary opening and closing control.

In such apparatus, the incipient electric arc at the separation of the contacts, is subjected to the force of Laplace which tends to direct it towards the pre-chamber. The combination of an electromagnetic coil control auxiliary with a bipolar circuit breaker has the effect of disturbing the arc start.

This disturbance results in both a loss of the component of the propulsive force of the arches, and a very significant increase in the lateral component of the Laplace force. This effect is more particularly visible on the arc located closest to the auxiliary. This problem arose especially during electrical endurance tests for very low test currents. After a certain number of cycles, it can be observed that the side walls can be burned and destroyed, causing thermal shutter malfunction problems and the risk of pollution of the contact area. The in-depth examination shows that there is a privileged side where this destruction appears, which suggests that Laplace's force is deviated laterally. The investigations carried out show the complexity of the impact on the arc departure and the interactivity of all the elements constituting the circuit-breaker; in particular, the strong electromagnetic impact of the coil of the remote control.

The remote control degrades the cutoff and electrical endurance by the electromagnetic field created by its coil. The document EP 0 508 846 A1 describes such an electrical protection device. In this apparatus the plate 23 is located below the coil 16 of the control device.

The present invention solves these problems and proposes a simple electrical protection apparatus in which the cutoff characteristics are improved, in particular by increasing the component of the propulsion force acting on the arc during the cut.

For this purpose, the subject of the present invention is an electrical protection apparatus according to claim 1.

According to a particular characteristic, the coil of the control device, seen from the front of the apparatus, is wound in a winding direction opposite to the winding direction of the coil (s) of the module (s). cut, the latter winding direction being seen from the upper part of the apparatus.

According to another characteristic, the winding direction of the coil of the control device is the counter-clockwise direction, while the coil (s) of the cutoff module (s) is (are) wound ( s) in a clockwise direction.

According to another characteristic, the aforementioned screen has a cross shape comprising two so-called first wings extending along the height of the apparatus substantially perpendicular to the longitudinal direction of the rail, and two said second wings extending in the longitudinal direction of the rail, the portion comprising these second wings and the aforementioned central portion joining these two wings being located substantially opposite the coil of the control device so as to cover substantially completely.

According to another characteristic, the aforementioned screen has a thickness of between 0.5 and 1.2 mm.

According to another characteristic, the magnetic screen is sandwiched between the envelope of the control device and that of the neighboring cut-off module.

According to another characteristic, this apparatus comprises means for pre-positioning said screen with respect to the housing of the control device or to the housing of the breaking module, these means comprising two centering pins provided on one of the housings cooperating with orifices. provided on the other housing, or a peripheral rib formed on one of said housings.

According to another characteristic, this electrical protection device is a low-voltage circuit breaker.

According to another characteristic, this control device is a remote control device.

According to another characteristic, this device is a bipolar low-voltage circuit breaker comprising two breaking modules.

• La figure 1 est une vue en perspective d'un disjoncteur de protection électrique bipolaire associé à un auxiliaire électromagnétique de commande d'ouverture et de fermeture des contacts dudit disjoncteur, selon l'invention,
• La figure 2 est une vue schématique de face, illustrant pour un disjoncteur selon l'art antérieur du même type que celui de la figure 1, les bobines électromagnétiques d'un dispositif de commande auxiliaire et des modules de coupure, ainsi que la trajectoire de l'arc électrique lors de la séparation des contacts,
• La figure 3 est une vue en perspective, illustrant de manière schématique, la partie intérieure d'un disjoncteur selon la figure 2,
• La figure 4 est une vue en perspective illustrant de gauche à droite, un dispositif de commande auxiliaire, un guide magnétique et des modules de coupure ,
• La figure 5 est une vue similaire à la figure 4, après montage du guide magnétique sur le disjoncteur, et
• La figure 6 est une vue en perspective illustrant un disjoncteur selon l'invention après fixation des modules de coupure sur le disjoncteur,
• La figure 7 est une vue en coupe du disjoncteur selon l'invention précité, selon un plan parallèle au plan du support de montage,
• La figure 8 est vue partielle en perspective, illustrant la bobine du dispositif de commande auxiliaire, le guide magnétique selon l'invention, et les modules de coupure, et
• La figure 9 est une vue similaire à la figure 2, illustrant l'arc électrique dans le cas d'un disjoncteur selon l'invention.

But other advantages and features of the invention will become more apparent in the detailed description which follows and refers to the accompanying drawings given solely by way of example and in which:

• The figure 1 is a perspective view of a bipolar electrical protection circuit breaker associated with an electromagnetic auxiliary control opening and closing contacts of said circuit breaker, according to the invention,
• The figure 2 is a schematic front view, illustrating for a circuit breaker according to the prior art of the same type as that of the figure 1 , the electromagnetic coils of an auxiliary control device and breaking modules, as well as the path of the electric arc during the separation of the contacts,
• The figure 3 is a perspective view, schematically illustrating, the inner part of a circuit breaker according to the figure 2 ,
• The figure 4 is a perspective view illustrating, from left to right, an auxiliary control device, a magnetic guide and breaking modules,
• The figure 5 is a view similar to the figure 4 after mounting the magnetic guide on the circuit breaker, and
• The figure 6 is a perspective view illustrating a circuit breaker according to the invention after fixing the breaking modules on the circuit breaker,
• The figure 7 is a sectional view of the circuit breaker according to the invention mentioned above, in a plane parallel to the plane of the mounting bracket,
• The figure 8 is a partial perspective view, illustrating the coil of the auxiliary control device, the magnetic guide according to the invention, and the breaking modules, and
• The figure 9 is a view similar to the figure 2 , illustrating the electric arc in the case of a circuit breaker according to the invention.

On the figure 1 , a low-voltage, modular, bipolar electric circuit breaker D according to the invention is shown comprising, from left to right, a remote control device 1 and two cut-off modules 2, 3, the device and the modules being housed in modular housings adapted to be attached side by side on a mounting rail (not shown). Each housing has a rear face 4 for attachment to the rail, two main faces 5, 6 by which the housings are placed side by side, a front face 7 forming a nose, an upper face 8 and a lower face 9, said faces comprising 10 input and 11 output terminals of the device.

In a manner known per se, each breaking module 2,3 comprises a magnetic tripping device capable of controlling the opening of the contacts in the event of a short-circuit in the circuit to be protected, as well as a thermal tripping device able to drive the opening of the contacts in case of overload in the circuit.

As more particularly illustrated on the figure 8 each magnetic tripping device comprises a coil 12 traversed by the current to be monitored and electrically connected to the fixed contact 13, said coil being traversed by an actuating rod 14 adapted to actuate the movable contact 15 in the event of a short circuit. The fixed and movable contacts 15 and 15 are located in a space 16 called prechamber in which the electric arc is formed before being moved to a breaking chamber 17.

The remote control device 1 mainly comprises an electromagnetic coil 18 able to act on the contacts 13, 15 so as to cause their opening or closing.

On the figure 2 in a bipolar circuit breaker D associated with an electromagnetic coil control auxiliary 1 according to the prior art, the electric arc 19 at the start is laterally deflected as explained above, which leads to a possible destruction of the walls side 20 of the corresponding housing. In this embodiment illustrated also on the figure 3 , the lateral component L of the Laplace force is very important compared to the propulsion component T.

As this is visible on the figures 3 and 7 to 9 , the coils 12,21 of the clipping modules 2,3 are substantially in the same plane parallel to the plane of the mounting bracket, the X axis of the coils of the clipping modules 2,3 extending substantially perpendicular to the Y axis of the coil of the control device 1.

As illustrated on Figures 4 to 9 and according to the invention, a plate-shaped part 22 made of a ferromagnetic material, having a general cross shape, is interposed between the control device 1 and the closest cut-off module 2 associated therewith. This part comprises a central portion 23 from which extend two wings 24,25 extending substantially perpendicular to the longitudinal direction Z of the mounting bracket and two wings 26,27 extending substantially parallel to this direction. This central portion 23 and the two wings 26, 27 extending substantially parallel to the aforementioned longitudinal direction Z are dimensioned so as to cover the coil 18 of the control device 1 substantially completely.

As illustrated on the figure 5 this piece 22 is sandwiched between the envelopes of the control device 1 and that of the cutoff modules 2, 3.

The pre-positioning of the part is carried out by means of two centering pins 28, 29 provided on the casing of the circuit-breaker intended to cooperate with orifices 30, 31 provided on the plate 22. Another embodiment of this pre- positioning could consist of a peripheral ribbing provided on one or other of the envelopes and for receiving said plate 22.

This piece is intended to constitute a magnetic guide for the arc and is held in final position by the assembly of the control device 1 on the circuit breaker formed by the two modules 2, 3, as shown in FIG. figures 6 and 7 .

Note also the presence, as illustrated on the figure 5 on the side of the plate 22, a notch 32 intended to allow passage of the fixing means of the coil 18 of the control device 1.

The thickness of the plate should not be too large, so that it does not constitute a shield whose function would be to stop the flow, but instead provide the magnetic guidance function.

This thickness will therefore advantageously be between 0.5 and 1.2 mm, with a preferred value of 1 mm.

Even if the primary function of this plate is not to achieve a shield, it will be noted that the cross shape of this plate will improve the shielding thereof.

According to the invention also, the control coil 18 of the control device 1 is wound, in front view of the apparatuses, in a direction opposite to the winding direction b of the coils 12,21 of the breaking modules 2,3, in top view of these.

Since the winding direction of the circuit breakers is usually clockwise in top view, the winding direction of the control coil 18 of the control device 1 will advantageously be counter-clockwise.

In operation, during the separation of the contacts 13, 15, this magnetic guide constituted by the above-mentioned plate 22 makes it possible to channel the magnetic flux lines and creates, at the point of separation of the contacts, more favorable conditions for the departure of arc, to straighten the latter so as to refocus it as illustrated on the figure 9 .

The invention makes it possible to obtain an electromagnetic effect consisting of a reduction of the lateral component L of the negative Laplace force of the order of 75% on the arc of the cut-off module closest to the remote control coil. . This results in an increase in the propulsion component T for each of the arcs respectively produced by the different breaking modules, this component becoming even greater than on a circuit breaker without associated control device. This increase with respect to a circuit-breaker without associated auxiliary control device being 20% on the arc furthest from the remote control device and of the order of 2000% on the arc closest to the coil of the electro magnet. The auxiliary control device can then be considered as a complementary arc-blowing device.

An electrical protection apparatus in which an associated control device no longer degrades the breaking of the breaking modules to which it is associated, nor the endurance by the electric field created by its coil, has thus been realized thanks to the invention. The surfaces of the side walls of the breaking modules are no longer degraded.

These results are obtained by means of a solution consisting in associating a thin magnetic guide with a particular winding convention of the coil of the control device and coils of the pole actuators.

The invention is particularly applicable to electrical switching devices such as circuit breakers controlled by a control device comprising an electromagnetic coil such as a remote control or a differential detection device, and more broadly to any actuator equipped with coil auxiliaries. electromagnetic control.

Of course, the invention is not limited to the embodiments described and illustrated which have been given by way of example.

Thus the screen may consist of one or more pieces made of a ferromagnetic material positioned in a vertical plane between the electromagnet and the nearest cutoff module.

Claims (10)

1. Electrical protection apparatus comprising at least one disconnection module (2, 3) mounted on a mounting support, and a control device with electromagnetic coil (1) juxtaposed with one of the abovementioned modules (2, 3) each disconnection module (2, 3) comprising two contacts (13, 15) of which one is mobile relative to the other between a first position in which the contacts (13, 15) are closed and allow the passage of the current and an open position in which the current is interrupted between the contacts and the abovementioned control device (1) comprising an electromagnetic coil (18) suitable for controlling the opening or the closing of the contacts (13, 15), the coil (18) of the control device being situated substantially facing the contact point(s) of the contacts of the disconnection module(s), the so-called first axis (Y) of the coil (18) of the control device extending substantially at right angles to the fixing plane whereas the axis (axes) (X) of the disconnection module(s) (2, 3) extend substantially parallel to the fixing plane, the so-called first axis extending substantially at right angles to the so-called second axis (axes) (X),
   this electrical protection apparatus comprises a magnetic screen (22) arranged in a plane substantially at right angles to the plane of the mounting support, said screen (22) being situated between the control device (1) and the closest disconnection module (2, 3) of said device facing the coil (18) of the control device (1), and comprising at least one ferromagnetic part (22) dimensioned so as to substantially completely cover the coil of the control device, said part producing the magnetic guidance of the arc (19) upon the separation of the contacts (13, 15) so as to augment the Laplace force propulsion component T acting on the arc (19) upon the separation of the contacts.
2. Electrical protection apparatus according to Claim 1, characterized in that the or each disconnection module comprises a coil (12, 21) of which the axis extends substantially at right angles to the axis of the coil (18) of the control device (1) and substantially parallel to the fixing plane, and in that the coil (18) of the control device (1), seen facing the apparatus, is wound in a winding direction (a) opposite to the winding direction (b) of the coil(s) (12, 21) of the disconnection module(s) (2, 3), the latter winding direction (b) being seen from the top part of the apparatus.
3. Electrical protection apparatus according to Claim 1 or 2, characterized in that the winding direction (a) of the coil (18) of the control device (1) is the anticlockwise direction, whereas the coil(s) (12, 21) of the disconnection module(s) (2, 3) is (are) wound in a clockwise direction (b).
4. Electrical protection apparatus according to any one of the preceding claims, characterized in that the abovementioned screen (22) is in the shape of a cross comprising two so-called first wings (24, 25) extending heightwise from the apparatus substantially at right angles to the longitudinal direction Z of the rail, and two so-called second wings (26, 27) extending in the longitudinal direction of the rail, the part comprising these second wings (26, 27) and the abovementioned central part (23) joining these two wings being situated substantially facing the coil (18) of the control device (1) so as to substantially completely cover it.
5. Electrical protection apparatus according to any one of the preceding claims, characterized in that the abovementioned screen (22) has a thickness of between 0.5 and 1.2 mm.
6. Electrical protection apparatus according to any one of the preceding claims, characterized in that the magnetic screen (22) is positioned sandwiched between the enclosure of the control device (1) and that of the adjacent disconnection module (2).
7. Electrical protection apparatus according to Claim 6, characterized in that it comprises means (28, 29, 30, 31) for pre-positioning said screen (22) relative to the casing of the control device (1) or to the casing of the disconnection module (2, 3), these means comprising two centring pins (28, 29) provided on one of the casings co-operating with orifices (30, 31) provided on the other casing, or else a peripheral rib produced on one of said casings.
8. Electrical protection apparatus according to any one of the preceding claims, characterized in that it is a low-voltage circuit breaker (D).
9. Electrical protection apparatus according to any one of the preceding claims, characterized in that the control device (1) is a remote control device.
10. Electrical protection apparatus according to Claim 8 or 9, characterized in that it is a double-pole low-voltage circuit breaker (D) comprising two disconnection modules (2, 3).

Images