Bidirectional double-pole double-break contactor with reversed magnetic fields

Description

TECHNICAL FIELD

[0001] The technical field of the invention is that of contactor chambers.

[0002] The invention relates to a double pole, double break, bidirectional contactor, which is adapted to be mounted on busbars.

[0003] A contactor is obtained which is compact and can be used in electrical power distribution, particularly in an aircraft. PRIOR ART

[0004] A contactor is a remote-controlled electrical switch used to establish or interrupt the flow of an electric current. The contactor can be single-pole, two-pole, three-pole or four-pole, depending on whether it has one, two, three or four power contacts (poles).

[0005] In the context of the invention, we are interested in a bidirectional bipolar or double pole double-break contactor (translation contactor). Such a bidirectional double pole double-break contactor makes it possible, for example, to simultaneously cut off the positive terminal and the negative terminal of an HVDC battery.

[0006] In a manner known and as illustrated in the figure 1 , a double-break two-way contactor comprises: a movable bridge 2 between a closed state and an open state, comprising a first movable contact 20 and a second movable contact 21; a first fixed contact 30, opposite the first movable contact 20, and a second fixed contact 31, opposite the second movable contact 21, the first and second movable contacts 20, 21 being, in the closed state, in contact with the first and second fixed contacts 30, 31 respectively, and the first and second movable contacts 20, 21 being distant, in the open state, from the first and second fixed contacts 30, 31 respectively; a pair of magnets, capable of generating a magnetic field B of constant direction, so as to generate a magnetic force to move an arc 9 appearing between the fixed contacts and the movable contacts of the movable bridge passing from a closed state to an open state;an arc extinguishing chamber 1 for extinguishing arcs having a first current direction, said arc extinguishing chamber comprising: four fin blocks 4 each having: a first 41 and a second end 42; fins 43 between the first end 41 and the second end 42 of the corresponding fin block 4; four arc guides 5, each arc guide leading from a movable contact of the movable bridge 2 towards its respective fin block 4.;

[0007] Arc blowing in the contactor is a magnetic blowing by permanent magnet. This is a proven technique, which is found in high voltage direct current (HVDC) contactors and circuit breakers. It generates a magnetic field which, by interacting with the arc, allows it to move according to the Laplace force.

[0008] The arc guides direct the arcs to their respective fin blocks, with the fin blocks serving as arc extinguishing devices. Each block allows an arc directed toward the block to be split and extinguished.

[0009] In reference to the figure 2 , which is a schematic diagram of the double electrical contacts of a double-break bidirectional contactor, it can be seen that the contactor comprises, on the one hand, first and second fixed contacts 30, 31 and, on the other hand, first and second movable contacts 20, 21 on a movable bridge 2. The first movable contact 20 is opposite the first fixed contact 30 and the second movable contact 21 is opposite the second fixed contact 31. The figure 2represents the movable bridge 2 in the open state. When the movable bridge 2 is in the closed state, a current i can move from the first fixed contact 30 to the second fixed contact 31 through the movable bridge 2. The contactor is said to be bidirectional, because the electrical flow of the current can be reversed in such a way that the current moves from the second fixed contact 31 to the first fixed contact 30 through the movable bridge 2, the direction of the physical current being reversed at the contacts 30, 20, 31, 21.

[0010] Unlike a single-pole contactor, a double-pole double-break contactor 12 has two breaking chambers 1a, 1b.

[0011] Furthermore, since it is desired that the integration of the contactor 12 in a distribution box 13 be done on busbars 15 and not by wiring (a “busbar” is an English term commonly used in the field of electrical distribution, which can be translated as “busbar” or “interconnection bar”, and which is an element allowing both a mechanical link and an electrical link), the two chambers are arranged parallel and adjacent (attached to each other), in order to minimize the bulk and to facilitate the exit of fixing lugs 8 for the installation of the contactor 12 in a distribution box 13. figure 3shows the installation of a double-pole, double-break, bidirectional contactor 12 in a distribution box 13 with a power busbar 15 and the directions of flow of the currents i. One pole of the connector can thus be connected, at the output of the distribution box, by a wiring 16, to the “+” terminal of a battery 14, and the other pole connected to the “-” terminal of the battery 14.

[0012] There figure 4 details a side view of a prior art double-pole double-break bidirectional contactor which can be mounted on busbars, the magnetic field B being in the same direction in the two breaking chambers 1a, 1b; the arcs when the power contacts open are also seen.

[0013] On the Figure 5 , we distinguish the two chambers 1a, 1b of the double pole bidirectional contactor according to a top view taken at the level of the section plane AA of the figure 4 . As can be seen in this Figure 5, the two breaking chambers of the double pole connector of the prior art are separated by an internal wall 11 common to the two chambers and a single pair 7 of magnets (the North South orientation being indicated for each magnet) makes it possible to create a magnetic field B in each of the two breaking chambers, the two fields being oriented in the same direction in the two breaking chambers 1a, 1b. There is furthermore, in each chamber, another discontinuous internal wall 17, arranged perpendicular to the internal wall 11, which makes it possible to isolate the adjacent fin blocks, and which has an opening to allow the passage of the movable bridge 2.

[0014] Due to this particular configuration, when the double pole, double break, bidirectional contactor opens, the Figure 5, four electric arcs are formed, two of which are directed towards the inside of the contactor (internal arcs 9). When the magnetic field is in the same direction in both breaker chambers, the two arcs that go inwards face each other. Therefore, the internal wall 11 separating the two breaker chambers must be an electrically insulating wall to avoid a short circuit. And, even with this insulating wall, given that the breaker chambers are closed but not airtight, there is still a risk that the two arcs will meet and become one (the arc path between the two poles is represented by the broken line 6), which would cause a short circuit directly between the two poles.

[0015] In addition, the walls behind the fins create a blockage in the airflow, which can prevent the arc from entering the fins. For the walls on the periphery of the contactor, this is not a problem because holes can be created in the walls or completely removed, but the wall 11 separating the two chambers cannot be removed due to the risk of short circuit.

[0016] In view of the above, the inventors sought to design a double-pole, double-break, bidirectional contactor which is compact, so that it can be mounted on busbars, and in which the risks of short-circuiting between the arcs are minimized and the circulation of air flows is facilitated. STATEMENT OF THE INVENTION

[0017] This goal is achieved by means of a double-pole, double-break, bidirectional contactor configured to be mounted on busbars (in fact, two parallel busbars), comprising, for each pole, a breaking chamber, in which are arranged: a movable bridge between a closed state and an open state, comprising a first movable contact and a second movable contact; a first fixed contact, opposite the first movable contact, and a second fixed contact, opposite the second movable contact, the first and second movable contacts being, in the closed state, in contact with the first and second fixed contacts respectively, and the first and second movable contacts being distant, in the open state, from the first and second fixed contacts respectively; a pair of magnets, capable of generating a magnetic field of constant direction, so as to generate a magnetic force to move an arc appearing between the fixed contacts and the movable contacts of the movable bridge passing from a closed state to an open state; four blocks of fins each having: a first and a second end; fins included between the first end and the second end of the corresponding block of fins;four arc guides, each arc guide leading from a movable contact of the bridge to one of the four fin blocks, each block having its own fin block; ; the two arc chutes being configured to simultaneously extinguish arcs having a first current direction, for one pole, and arcs having a second current direction, for the other pole, the first and second current directions being opposite.

[0018] The contactor is characterized in that the first and second breaking chambers are arranged parallel and adjacent to each other, defining an adjacent zone, the first and second breaking chambers being in fluid communication at least partly in the adjacent zone; and in that there are four magnets and the pairs of magnets of the two poles are arranged in such a way that the magnetic fields generated within the two poles are of parallel direction, but of opposite directions.

[0019] According to the invention, the joining zone is parallel to a direction of movement between the closed state and the open state of each of the two movable bridges.

[0020] According to a first variant, the first and second breaking chambers are separated by an internal wall common to both chambers, said internal wall being provided with several through holes. The through holes allow the passage of internal air flow between the two chambers.

[0021] According to a second further variant, the first and second breaking chambers are separated only in part by an internal wall, possibly provided with several through holes.

[0022] According to a third variant, no internal wall separates the first and second cutting chambers. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other aspects, aims, advantages and characteristics of the invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the appended drawings in which: there figure 1 represents, in a side view and in section, a breaking chamber of a single-pole double-break bidirectional contactor of the prior art; figure 2 is a schematic diagram of the double electrical contact of the double-break bidirectional contactor of the figure 1 ; there figure 3 is a schematic view of the installation of a double-pole, double-break, bidirectional contactor in a distribution box with power busbars; figure 4 represents, in a side view and in section, a double-pole, double-break, bidirectional contactor according to the prior art; Figure 5 is a top view of the prior art double-pole double-break bidirectional contactor in a section at plane AA of the figure 4 ; there figure 6 is a top view of an embodiment of the double-pole, double-break, bidirectional contactor according to the invention; figure 7is a side and sectional view of an embodiment of the double-pole, double-break, bidirectional contactor of the invention; figure 8 is a side and sectional view of another embodiment of the double-pole, double-break, bidirectional contactor of the invention (partial internal wall); figure 9 is a side and sectional view of another embodiment of the double-pole, double-break, bidirectional contactor of the invention (removal of the internal wall).

[0024] It is specified that in the figures 1 , 4 , 5, 6 , 7, 8, 9 , the straight black arrows with thin lines represent the current direction, the large straight arrows with striped fill represent the magnetic field direction, the medium or small straight arrows with no fill represent the Laplace force direction and the arc travel direction.

[0025] As is well known, circles with a dot or a cross represent a direction towards or away from the observer. DETAILED DESCRIPTION

[0026] The invention consists of configuring the contactor so that the two magnetic fields produced in the two breaking chambers are parallel, but in opposite directions. This allows the electric arcs created when the power contacts of the two poles open to be pushed in the same direction.

[0027] To do this, considering a plane of symmetry separating the two cutting chambers, a pair of magnets 7a, 7b is placed in each cutting chamber 1a, 1b and they are arranged so that the polarity of a magnet of a pair in a chamber is the opposite of the polarity of the magnet of the other pair arranged symmetrically with respect to the plane of symmetry.

[0028] This movement of the arcs in the same direction towards the cutting fins ensures that there will be no electrical connection between the two poles of the contactor due to electric arcs catching between them.

[0029] Indeed, if the magnetic fields in the chambers are in opposite directions, as is the case when using two pairs of magnets 7a, 7b arranged as illustrated in the figure 6 for example (the figure 6 showing a top view of a busbar-mountable double-pole double-break bidirectional contactor according to one embodiment of the invention, the magnetic fields being opposite in the two breaking chambers), the internal arcs 9 produced (i.e. those heading towards the inside of the contactor) are arranged diagonally to each other and therefore the risk of them joining is reduced.

[0030] Thus, by reorganizing the orientation of the internal arcs 9 diagonally by a specific arrangement of the magnets, the internal arcs are not sent towards each other between the two extinguishing chambers 1a, 1b and it is then possible to reduce, or even eliminate, the internal wall separating the two extinguishing chambers. This has the effect of not blocking the internal air flows, and consequently, of not preventing the internal arcs from entering their respective fin blocks.

[0031] The two extinguishing chambers are arranged parallel and are joined to each other, thus defining a joining zone 10. In this joining zone, the internal wall common to the two extinguishing chambers can be replaced by a lightened internal wall, or the internal wall can be completely removed. The two extinguishing chambers are thus in fluid communication in this joining zone.

[0032] The two breaking chambers can thus be separated from each other by a partially open internal wall 110 ( figure 8 ), such as a partition with several holes or a filter that lets air through. Preferably, the inner wall is made of an electrically insulating material. It can be a wall with several holes that can be made of a plastic material. But it is also possible to completely remove the inner wall ( figure 9 ). This results in optimized gas exchange within the contactor, which improves the quality of electric arc breaking.

[0033] In summary, by reversing the magnetic fields between the two chambers, the internal arcs produced when using the arc chutes in series do not face each other. This allows the internal wall that usually separates the two chambers to be removed at least partially, blocking airflow and degrading contactor performance. This allows for less complicated insulation between the two chambers and a reduction in the risk of short-circuiting between the two internal arcs. It also allows the useful volume of the second chamber to be used to send the internal arcs produced in the first chamber and vice versa.

Claims

1. Double-disconnect double-pole bidirectional contactor configured to be mounted on two parallel busbars, comprising, for each pole, an interrupter chamber (1a; 1b), in which the following are disposed: - a bridge (2a; 2b) able to move between a closed state and an open state, comprising a first moving contact (20a; 20b) and a second moving contact (21a; 21b); - a first fixed contact (30a; 31a) facing the first moving contact (20a; 20b), and a second fixed contact (30b; 31b) facing the second moving contact, (21a; 21b) the first and second moving contacts (20a; 20b; 21a; 21b) being, in the closed state, in contact with respectively the first and second fixed contacts (30a; 31a), and the first and second moving contacts (20a; 20b; 21a; 21b) being distant, in the open state, from respectively the first and second fixed contacts (30a; 31a; 30b; 31b); - a pair of magnets (7a; 7b), able to generate a magnetic field with a constant direction, so as to generate a magnetic force for moving an arc appearing between the fixed contacts (30a; 30b; 31a; 31b) and the moving contacts (20a; 20b; 21a; 21b) of the moving bridge (2a; 2b) passing from a closed state to an open state; - four blocks of fins (4a; 4b) each having: - a first (41) and second end (42); - fins (43) lying between the first end (41) and the second end (42) of the corresponding block of fins (4a; 4b); - four arc guides (5a; 5b), each arc guide being directed from a moving contact (20a; 20b; 21a; 21b) of the moving bridge movable (2a; 2b) to its respective block of fins (4a; 4b); the two interrupter chambers being configured to simultaneously extinguish arcs having a first current direction for one pole, and arcs having a second current direction for the other pole, the first and second current directions being opposed; the contactor being characterized in that the first and second interrupter chambers (1a; 1b) are disposed parallel and are up against each other, defining a joining zone (10) that is parallel to a direction of movement between the closed state and the open state of each of the two moving bridges, the first and second interrupter chambers being in fluid communication at least partly in the joining zone (10); and in that there are four magnets and the pairs of magnets (7a; 7b) of the two poles are disposed so that the magnetic fields generated in the two poles are in a parallel direction but in opposite directions.

2. Contactor according to claim 1, wherein the first and second interrupter chambers are separated by an internal wall common to the two chambers, said internal wall 110 being provided with a plurality of through holes.

3. Contactor according to claim 1, wherein the first and second interrupter chambers are separated only partly by an internal wall, optionally provided with a plurality of through holes.

4. Contactor according to claim 1, wherein no internal wall separates the first and second interrupter chambers.