TWO-ELECTRIC-POLE CIRCUIT BREAKER ACTUATED BY A COMMON PYROTECHNIC DEVICE

Abstract

Two electric poles are controlled in one and the same circuit breaker by an undivided opening mechanism controlled by a pyrotechnic actuator. The opening of the circuit that is brought about by this actuator, which is fast for a large opening travel of the mobile contacts, makes it possible to extinguish electric arcs under good conditions. The poles may be placed in series on one and the same electrical circuit in order to reduce the potential difference across the terminals of each of them, thereby further increasing the effectiveness of the circuit breaker in terms of arc extinguishing.

Claims

1. Electric cutoff device, comprising: two electric poles, each of the poles comprising at least a fixed contact and a mobile contact, which is mobile between a closing state in which it touches the fixed contact, and an opening state in which it is separated from it; a pyrotechnic actuator for switching the mobile contacts from the closing state to the opening state; characterised by: a part for linking the mobile contacts said linking part being connected to the actuator by a transmission; stops carried by the linking part, distant from the mobile contacts in the closing state and respectively engaged on the mobile contacts in the opening state; the stops being placed on the linking part so as to be engaged simultaneously on the mobile contacts.

2. The device according to claim 1, wherein the linking part is a rectilinear rod, the stops are spread out on the rod, and the mobile contacts are aligned in the direction of the rod.

3. The device according to claim 2, wherein the pyrotechnic actuator comprises a piston mobile parallel to the rod, and a pivoting connecting rod connecting the piston to the rod.

4. The device according to claim 1, wherein the pyrotechnic actuator comprises an envelope mounted on an outer face of a main case of the cutoff device that contains the electric poles and the linking part, and wherein a transmission passing through a wall of the case connects the linking part to a mobile part of the pyrotechnic actuator.

5. The device according to claim 1, further comprising means for cutting off an electric arc that includes permanent magnets, divergent tracks for capturing opposite ends of the arc, and fins for sectioning the arc located between the tracks.

6. The device according to claim 4, wherein the envelope of the pyrotechnic actuator contains an anti-return device, which prevents the return of the mobile part to an initial position, when a pyrotechnic charge of the pyrotechnic actuator has been ignited.

7. The device according to claim 1 wherein the electric poles are housed in superimposed compartments of a case, the pyrotechnic device is assembled to an outer side of the case, and openings for evacuation of gas are made through at least one other side of the case to connect the compartments to an outside environment.

8. The device according to claim 7, wherein the case is substantially parallelepipedic, and comprises a control compartment aligned with the compartments housing the electric poles, the fixed contacts are placed through two first opposite sides of the case, and the openings are made through two other opposite sides of the case.

9. A direct-current circuit, the cutoff device according to claim 1, wherein the poles are placed at two portions of the circuit connected in series.

10. A method comprising using the direct-current circuit according to claim 9, in an electric distribution circuit of an airplane.

Description

[0020] The invention will now be described in its various aspects, features and advantages, via the following drawings, which illustrate a specific embodiment thereof, given for purely illustrative purposes:

[0021] FIG. 1 is a diagram of the circuit breaker according to the invention;

[0022] FIG. 2 shows in more detail the inner structure of the circuit breaker, with the actuation elements and the electric poles;

[0023] FIG. 3 shows the circuit breaker in an outside view;

[0024] FIG. 4 shows a cross-section of the circuit breaker perpendicularly to FIG. 2; [0025] and FIG. 5 shows a circuit on which the circuit breaker is installed.

[0026] The circuit breaker mainly comprises, according to FIG. 1, two electric poles 1 and 2, each comprising a pair of fixed contacts 3 and 4 as an extension but separate, and a mobile contact 5, moveable perpendicularly to the alignment of the fixed contacts 3 and 4 so as to join them and connect them, which gives a state of closing of the electric circuit in which the pole 1 or 2 is installed, or on the contrary be separated from them, which gives a state of opening of the circuit.

[0027] The mobile contacts 5 are connected to each other by a rod 6, which allows to move them together in order for the opening and closing states of the two poles 1 and 2 to be almost simultaneous. A pyrotechnic actuator 10 allows to move the rod 6 in its direction of extension by a transmission 11. The movements of the mobile contacts 5 are carried out by the pyrotechnic actuator 10. This occurs in the case of a short-circuit, in which the intensity of the current can reach for example 25 times the usual intensity. The use of the pyrotechnic actuator 10 allows to obtain both a greater travel of the mobile contacts and a much faster speed of separation of the contacts towards the opening state, capable of extinguishing the arcs and effectively opening the electric circuit on which the circuit breaker is placed, even in these difficult circumstances.

[0028] The mobile contacts 5 are suspended on the rod 6 by springs 12 which allow to apply them onto the fixed contacts 3 and 4 with sufficient force in the closing state, without mechanical rupture or permanent deformation, by compressing the springs 12.

[0029] Reference is made to FIG. 2. The poles 1 and 2 are housed in a case 13 and more precisely in two superimposed compartments 14 and 15 of the latter. A control compartment 16, located on the others, contains the top of the rod 6.

[0030] The pyrotechnic actuator 10 is located outside the case 13, at the height of the compartment 14 immediately under the control compartment 16. It comprises an envelope 17, assembled onto the case 13 of the circuit breaker strictly speaking in a way that can be disassembled, in which a piston 18 that divides its inner volume into an upper chamber 19 and a lower chamber 20 slides. The rod of the piston 18 protrudes from the envelope 17. A pivoting connecting rod 20 is articulated at its ends to the top of the rod of the piston 18 and to an upper part of the rod 6 for actuating the mobile contacts 5. It pivots around a pivot 21 established in the control compartment 16, and passes through the wall of the case 13 via a slot thereof. The transmission 11 is thus composed of the connecting rod 20 and the pivot 21. A pyrotechnic charge 23 is disposed on the envelope 17.

[0031] The rod 6 is provided with two stops 24 which extend below the mobile contacts 5 and allow to lift them when the rod 6 is moved upwards, and to open the poles 1 and 2.

[0032] The pyrotechnic actuator 10 further comprises a blocking device 25 that can consist of a pin and which prevents the movements of the piston 18 as long as the pyrotechnic charge remains intact, and an anti-return device 26, which can consist of an elastic blade and which prevents the return of the piston 18 to its initial position, when the pyrotechnic charge has been ignited. The pyrotechnic actuator 10 is mounted on the case 13 of the circuit breaker by screws 27 (not shown completely) that allow to replace it easily.

[0033] When the pyrotechnic actuator 10 is used, the explosion gases coming from the pyrotechnic charge 23 spread through the upper chamber 19 and increase the pressure there until the rupture of the blocking device 25. The piston 18 is lowered in the vertical direction, in the downward direction labelled Z.sup.?, the connecting rod 20 pivots and the rod 6 rises in the opposite direction Z.sup.+. The stops 24 touch the mobile contacts 5 and raise them, while bringing about the opening state of the poles 1 and 2; their travel and their speed of opening are sufficient to produce the extinction of the four electric arcs that appear between the mobile contacts 5 and the fixed contacts 3 and 4, and which are thus four in number. The devices for extinguishing arcs that will now be described, while also using FIGS. 3 and 4, also facilitate their extinction.

[0034] Magnets 28 are disposed in the case 13 at the height of the poles 1 and 2. Pairs of conductive tracks 29 and 30 are associated with each arc and each fixed contact 3 or 4. In each of them, the upper track 29 and the lower track 30 are close to one another near the pole 1 or 2, and move apart while forming an angle towards the sides of the case 13. Horizontal fins 31 replace the wall of the case 13 at this location, while leaving between them outlet openings from the case 13 towards the outside. And nozzles 32, which are curved plates, extend outside of the case 13 in front of the openings, to guide and bend upwards the flows of pressurised gas coming from the compartments 14 and 15 and produced by the arcs. The nozzles 32, the fins 31, as well as the tracks 29 and 30, extend on two opposite sides of the parallelepipedic case 13, while the pyrotechnic actuator 10 and the magnets 28 are disposed on the two other sides, where the fixed contacts 3 and 4 also end.

[0035] The operation of the device is the following. When the poles 1 and 2 go to the opening state and arcs form between the fixed contacts 3 and 4 on the one hand and the mobile contacts 5 on the other hand, the magnets 28 move the feet of the arcs onto the adjacent ends of the conductive tracks 29 and 30, then along these tracks towards the outside of the case 13; the arcs are elongated via the increasing distance between the upper 29 and lower 30 tracks, lose their cohesion and end up being sectioned by the fins 31. The very hot gases produced by the arcs are evacuated from the case 13 by the nozzles 32, and ejected upwards.

[0036] Throughout this detailed embodiment, it was supposed that the direction Z is vertical, the rod 6 extending in this direction, and the compartments 15, 14 and 16 being superimposed in this order in the direction Z.sup.+. The invention would function just as well with different orientations, and different arrangements, of the circuit breaker.

[0037] FIG. 5 shows a favourable use of the invention. The circuit breaker carries the reference 33, and it is disposed on an electric circuit 34 powered by a generator 35 of direct current, optionally bidirectional. One of the branches 36 of the circuit 34 carries the electric pole 1, and another branch 37, in series with the previous one, the other electric pole 2. Loads 38, which consume electric power, are placed at various positions of the circuit 34, in particular between the poles 1 and 2. These can be apparatuses inside an airplane and which are powered by the generator 35. The circuit breaker 33 can of course be used for other uses or other electric circuits.