EP0516640A1

EP0516640A1 - Quick-action circuit breaker.

Info

Publication number: EP0516640A1
Application number: EP91903322A
Authority: EP
Inventors: Roland Blochouse
Original assignee: ACEC Transport SA
Current assignee: Alstom Belgium SA
Priority date: 1990-02-23
Filing date: 1991-02-18
Publication date: 1992-12-09
Anticipated expiration: 2011-02-18
Also published as: WO1991013452A1; EP0516640B1; HU208590B; CA2076675A1; JPH071659B2; JPH05504229A; DE69100511T2; DE69100511D1; ZA911157B; PL167473B1; KR0183451B1; AU653329B2; AU7210591A; CZ279386B6; BR9106069A; US5521569A; HUT61127A; ES2044724T3; CA2076675C; SK278078B6

Abstract

On décrit un disjoncteur hyper-rapide assisté par un circuit de commande à semi-conducteurs comportant une bobine de répulsion, un disque de répulsion (37) associé à un pont de contact (39) portant les contacts mobiles (41), ledit disque de répulsion (37) collaborant avec ladite bobine de répulsion (35), un moyen de retenue des contacts à l'état fermé agissant sur une queue solidaire du disque de répulsion (37) et un moyen d'amortissement (97) qui comporte une tige plongeuse (95) solidaire du disque de répulsion (37) et un réservoir (99) contenant du fluide destiné à absorber l'énergie cinétique de l'ensemble disque de répulsion (37) - queue (43) - tige plongeuse (95) lors de la répulsion par la bobine de répulsion (35), par adaptation des formes de la tige plongeuse (95) et du réservoir (99) l'une par rapport à l'autre de manière à disposer de sections d'évacuation de fluide variables en fonction de la course de la tige plongeuse (95). La course se faisant en deux temps, accélération avec grande section de passage et course de freinage avec une section de passage progressivement réduite.A hyper-fast circuit breaker assisted by a semiconductor control circuit comprising a repulsion coil, a repulsion disk (37) associated with a contact bridge (39) carrying the movable contacts (41), said pressure disk is described. repulsion (37) collaborating with said repulsion coil (35), a means for retaining the contacts in the closed state acting on a tail integral with the repulsion disc (37) and a damping means (97) which comprises a rod plunger (95) integral with the repulsion disc (37) and a reservoir (99) containing fluid intended to absorb the kinetic energy of the repulsion disc (37) - tail (43) - plunger rod (95) assembly during repulsion by the repulsion coil (35), by adapting the shapes of the plunger rod (95) and the reservoir (99) relative to each other so as to have variable fluid discharge sections according to the stroke of the plunger rod (95). The race is done in two stages, acceleration with large passage section and braking stroke with a progressively reduced passage section.

Description

HYPER-FAST CIRCUIT BREAKER

Subject of the invention

This invention relates to a hyper-fast current limiting circuit breaker which can be used on average, and more particularly suitable for electric traction, in rolling stock or fixed equipment. It relates more particularly to the mechanical part of a hyper-fast circuit breaker which is equipped with an electronic control circuit. Summary of the technique It is well known that electrical networks such as those used in traction as in industry are becoming more and more complex and powerful. The design of switching devices must evolve to cut larger and larger currents and reduce maintenance costs. A new generation switchgear must be quick to limit the current and reduce the mechanical and thermal stresses of the entire installation as well as the wear of its contacts and its blowing box. Currently, the breaking devices include fast or ultra-fast mechanisms for opening the contacts and a blowing box in which the arc created is confined and cooled. These devices incur significant costs due to maintenance interventions and the replacement of wearing parts. Among the problems encountered, it is known that the in¬ terruption of an electrical circuit is likely to cause excessive speed of movement of elements of the operative device. It may be necessary to master the speed of these elements for a short time after the interruption. The higher their speed, the more the braking which is imposed on them must be effective.

By way of illustration, mention may be made, for example, of the document FR-A-2 438 333 which describes a conventional electrical power switch, equipped with a shock absorber comprising a cylinder completely filled with oil in which moves a piston so connected hinged to the switch. This piston, which is provided with orifices, is braked in places along its stroke in the cylinder, whatever the direction of its movement.

Another example is given by document DE-U-6606297 which describes a damping pump for an electrical circuit breaker; a piston provided with orifices closable by return valves also moves in a cylinder containing damping liquid. The structure of this device is designed to allow, when switching off, to quickly extinguish intense electric arcs, while also extinguishing, at a suitable extinction distance, critical electric arcs, of low intensity.

Various associations between semiconductor mechanisms and control circuits have been proposed. European patent application No. 0 184 566 describes an apparatus in which the cut-off, without significant arc, is obtained by the addition of an oscillating circuit, controlled by semiconductors and whose inductor is used as a repulsion coil , to a hyper-fast mechanism with magnetic retention in which the same element acts both as a repulsion disc and as a movable contact bridge. The mechanism is associated with an oscillating circuit by means of power semiconductors and comprises in particular:

- a spiral repulsion coil, located in an insulating mass and acting as a choke of the oscillating circuit,

- a metal disc acting as a contact bridge and collaborating with the repulsion coil; - a mobile reciprocating assembly;

a permanent magnet or a holding coil and a magnetic yoke inserted in this mobile assembly,

- a frame collaborating with the magnetic yoke in connection with the disc.

In the case of the apparatus described therein, a repulsion effort is obtained which very quickly takes on considerable importance. The displacement of the repulsion disc is stopped on shock absorbers described as being a layer of deformable material.

European patent application No. 0 348 584 proposes a hyper-fast circuit breaker assisted by a semiconductor control circuit, comprising a repulsion coil, a repulsion disc associated with a contact bridge carrying the movable contacts, said repulsion disc collaborating with said repulsion coil, and a means for maintaining the contacts in the closed state, hyper-fast circuit breaker in which the holding means consists of a retaining spring acting on the repulsion disc associated with the bridge contact via a retaining means acting on a shank integral with said repulsion disc, retaining means which exerts sufficient pressure to resist an imposed contact pressure and which is arranged in a retractable manner when the disc is repelled under the effect of the repulsion coil. The damping or braking means is not described there in detail but, in the figures, a conventional damper has been shown.

In order to enable obtaining high acceleration to separate as quickly as possible the contacts of the circuit breaker, it ^is provided that the average amortis¬ ment or braking does not act on the movable part during a first portion of the race. This is why the movable part has been separated from the damping means by providing a free stroke for the movable part before the latter is slowed down. As a result, when the moving part encounters the damping or braking means at full speed, there is a violent impact generating various destructions, all the more so when one is in presence of accelerations of the order of 30,000 g and speeds of the order of 30 m / s.

In addition, conventional damping means use a fluid which is forced to pass through one or more orifices to create pressure drops by increasing speed. In view of the significant accelerations and speeds of the mobile part to be braked, the fluid speeds are so high that the jets of the latter are capable of destroying elements such as seals or guide nozzles. Such a problem is likely to arise in a damping pump such as that described in the document DE-U-6 660 297 mentioned above.

In addition, after an electrical circuit breaking operation, the mobile part of the circuit breaker and the mobile part of the damping means are at the end of the travel and the circuit breaker must be reset and therefore the electric circuit must be closed. In the case of the damping means described, the movement of the active part of the damping means is generally slower than that of the mobile part of the circuit breaker, the latter having to be rapid in order to avoid the formation of pre -bows. It follows that, if the circuit breaker trips again, before the active part of the damping means is returned to the starting position, the mobile part of the circuit breaker no longer finds a brake and comes crashing against the active part of the means of depreciation.

An attempt has been made to resolve this difficulty by connecting the mobile parts to each other by means of a game corresponding to free travel or by using a return spring on the damping means. These solutions however resist very badly to impacts and require frequent maintenance and / or replacement. Purpose of the invention

The present invention aims to provide a hyper-fast circuit breaker which does not have the abovementioned drawbacks, more particularly a hyper-fast circuit breaker of the aforementioned type equipped with a damping means which allows significant acceleration at the start of the stroke. the movable part of the circuit breaker and progressive braking, without rebounding and without using a mechanical stopper, at the end of the race. The damping means must be provided to allow an acceleration of 1 order of 30,000 g or more providing a speed of up to 40 m / s over a very reduced distance of 1 order of 2 to 3 mm then to brake gradually the moving part until stopping on a stroke of 30 to 40 mm by limiting the solli¬ citations. It must be simple and robust in construction and inexpensive and not require frequent maintenance. Essential elements of the invention

In accordance with the present invention, the hyper-fast circuit breaker assisted by a semiconductor control circuit, comprises a repulsion coil, a repulsion disc associated with a contact bridge carrying the movable contacts, said repulsion disc collaborating with said repulsion coil, a means for retaining the contacts in the closed state, which exerts sufficient pressure to resist an imposed contact pressure and which is arranged in a liberal manner during the repulsion of the disc under the effect of the repulsion coil, and a damping means, said damping means comprising a plunger rod integral with the repulsion disc and a reservoir containing fluid intended to absorb the kinetic energy of the repulsion disc - plunger rod assembly during repulsion by the repulsion coil, by adapting the shapes of the plunger rod and the reservoir relative to each other so as to have fluid evacuation sections that vary depending on the stroke of the plunger rod. The present ^invention thus provides a hyper-rapid circuit breaker described above equipped with a means of easy ment depreciation, which allows braking of the movement of the movable portion of said circuit breaker without impact against a stop that mécani¬ mobile or fixed , on a reduced stroke, while allowing rapid opening of the contacts at the start of the stroke. Indeed, if the shapes of the reservoir and of the plunger rod are adapted so that at the start of the stroke the discharge section is relatively large and that as as the plunger rod sinks into the fluid reservoir, said section narrows, braking is progressive while allowing significant acceleration at the start of the race. Since, moreover, the plunger rod is integral with the repulsion disc, the apparatus does not suffer the drawbacks due to the impacts of the movable part of the circuit breaker on an active part of the damping means.

Preferably, the repulsion disc-plunger rod assembly is in one piece. There is no possible mechanical play between these elements, which move at the same speed after repulsion. This embodiment is specially adapted to a hyper-fast circuit breaker, in which the very high accelerations and speeds reached would quickly cause degradation of elements connected together by mechanical means with one or more degrees of freedom. The repulsion disc-plunger rod assembly may consist of a single piece or of several pieces joined together, for example by welding, or by assembly. These parts can in particular be screwed under a prestress such that no play is likely to appear between them during accelerations or decelerations linked to the operation of the hyper-fast circuit breaker.

We also note that the device of the invention does not require any particular mechanism such as nozzles, or mobile mechanisms such as valves, etc. which are generally sensitive to breakdowns and which do not require a spring. whose disadvantages have been described above. The movement of a fluid which does not undergo any wear or rupture is used for braking. In the event of resetting of the circuit breaker, the damping means is immediately ready to enter into action again, even if the stroke has been incomplete.

Another advantage lies in the fact that the device of the invention is self-centering. For reasons of simplification of manufacture, the reservoir advantageously has an essentially cylindrical shape and the plunger rod has a profiled end widening from the end. It has been found that a profiled shape constituted by a succession of truncated cones having different angles of conicity, or by a continuous curve making it possible to obtain a braking force as constant as possible. The braking characteristic can be adjusted by adapting this curve. It is also possible to provide a substantially straight cylindrical or rectangular plunger rod associated with a reservoir, the internal face of which is profiled and is for example made up of a succession of truncated cones with different taper relative to one another or a continuous curve to obtain the most constant braking force possible.

As already mentioned in European patent application No. 0 348 584, the movable part of the hyper-fast circuit breaker is made of a relatively light material in order to reduce inertia. Similarly, the plunger rod can also be made of a light material, in particular a high-strength aluminum alloy. The increase in the mass of the mobile part is thus relatively small compared to the circuit breaker described in European patent application No. 0 184 566 or 0 348 584 (mentioned above).

It should also be noted that the frei¬ stroke stroke is independent of the maximum speed reached by the movable part of the circuit breaker according to the invention. Brief description of the figures

The invention is described in more detail below, in support of the drawings in which:

- Figure 1 is an overall sectional view of a circuit breaker according to the invention; - Figure 2 is a schematic detail view of the movable part of a hyper-fast circuit breaker, the arming orga¬ nes of the circuit breaker and the casing thereof being omitted for reasons of clarity and - Figure 3 is a schematic view of a variant of execution. Detailed description of a preferred embodiment

In the figures, reference marks identical represent identical or analogous elements. The circuit breaker 1 according to the present invention comprises a cylinder 3 closed at one end by a bottom cover 5 which is fixed thereto by means of a flange 7, a ring 9 housed in a corresponding groove 11 of said cylin¬ dre, the cover being tightened by means of screws or bolts 13, and closed at the other end by a second cover 15 which is fixed thereto in a similar manner by a flange 17, a ring 19 and screws or bolts 21. Said cylinder 3 has a piston inside

25 which can slide therein, and a pres¬ sion spring 27 which is supported on the bottom cover 5 and on a shoulder 29 formed in said piston. Said piston is surmounted by a sleeve 31 which passes through the cover 15 in its corresponding central opening 16. Said sleeve 31 is surmounted, at its free end, by the retaining means bearing the general reference 33.

The circuit breaker according to the present invention is surmounted by a repulsion coil 35 advantageously cast in a resin 35 *, the whole being assembled by bolts or threaded rods 36.

It also comprises a repulsion disc 37 associated with a contact bridge 39 carrying the movable contacts 41, and with a tail 43 and plunger rod 95 described in more detail below.

The retaining means 33 mounted on the end of the sleeve 31 by screwing for example comprises a plurality of balls or rollers 51 which are applied against the tail 43 of the repulsion disc 37 by means of an adjustable pressure. Indeed, a pusher 53 actuated by a spring 55 housed in a guide 57, preferably 'cylindrical, closed by a cover 59, and provided with a stop 61 preventing excessive pushing of the pusher, presses on a ball or roller 51.

The tail 43 is made integral with the repulsion disc 37. The tail 43 preferably comprises 4 inclined planes 62 which deviate from the axis 38 away from the repulsion disc 37 and is provided at the end close to the repulsion disc 37 of a shoulder 63 and, at the end free, of a groove 65. The circuit breaker further comprises a damping means described in more detail later. In the rest state, the spring 27 which is preferably precompressed keeps the piston 25 and, therefore, the sheath 31 in the high position, the repulsion disc being in the low position, away from the repulsion coil. ¬ sion.

To arm the circuit breaker in accordance with the present invention (left part of FIG. 1), it is necessary to introduce pressurized air through the conduit or conduits 75 formed in the cover 15. The chamber delimited by the wall of the cylinder 3, the cover 15 and the piston 25 is filled with compressed air and under the pressure thus exerted, the retaining spring 27 is compressed and the piston 25 is lowered carrying with it the sheath 31 and the retaining means 33 A seal 77 maintains the seal between the sleeve 31 and the cover 15. Another seal 79 is intended to maintain the seal between the piston 25 and the cylinder 3. In order to prevent the means retaining 33 does not drag with it the repulsion disc 37, given the pressure of the balls or rollers 51 on an inclined surface 61 relative to the axis 38, said disc 37 is retained by fixed stops 83. There it should be noted that the cylindrical wall of the piston 25 also plays nt the role of mechanical stop of the res¬ spell 27 preventing it from being compressed with joint turns. The cylindrical wall is also dimensioned in such a way that, when the spring 27 is compressed to the maximum, the balls or rollers 51 engage in the grooves 65.

To close the circuit breaker 1 according to the present invention da: _s the best conditions, that is to say rela¬ tively quickly, it is necessary to ensure that the retaining spring 27 can quickly release the stored energy . To do this, it is possible to put compressed air to the atmosphere through exhaust pipes 85 possibly fitted with quick-release valves. In this case, the formation of pre-arcs is limited. The sleeve 31 integral with said piston 25 drives with it, via the retaining means, and more particularly the balls or rollers 51, the tail 43, the plunger rod 95 and, consequently, the repulsion disc 37 until the bridge contact carrying the movable contacts comes into contact with the fixed contacts (figure 1, right part).

The force of the springs 55 must therefore be sufficient to maintain the balls or rollers 51 in the grooves 65 during this step and to ensure optimum contact pressure.

Suppose now that the current increases unacceptably in the electrical circuit in which is inserted the circuit breaker according to the present invention. In this case, the electronic control circuit sends a current pulse in the shape of a warhead in the repulsion coil 35 and by electrodynamic effect on the currents induced in the disc 37. This results in the establishment of a particularly high repellency. This high force makes it possible to dislodge the balls or rollers 51 from the grooves 65 by crushing the springs 55 thus releasing the movable pulley. The repulsion disc associated with the contact bridge 39 and the tail 43 secured to the plunger rod 95, subjected to the repulsion force undergoes a particularly high acceleration; this reduces the risk of arcing and contact wear or quickly creating a sufficient distance between the fixed and mobile contacts.

The repulsion disc thus accelerated between 20,000 and 40,000 g at speeds between 10 and 50 m / s over 1 to 5 mm must then be braked over a stroke of 20 to 40 mm. The braking role is played by the damper 97 and by the balls or rollers 51 which also allow a downward immobilization of the disc 37.

With reference to FIG. 2, the damping means 97 essentially comprises the plunger rod 95 attached to the repulsion disc 37 and a fluid reservoir 99. The shapes of the rod 95 and of the reservoir 99 are adapted such so that the section of the rod which enters the tank 99 varies the annular discharge section fluid between said rod and said reservoir during its movement. According to the embodiment shown, the reservoir 99 has an essentially cylindrical shape comprising a conical profiled zone while the end of the rod 95 is constituted by a succession of truncated cones having a different angle of conicity one the other. As a result, the annular leakage section through which the fluid 101 contained in said reservoir 99 is expelled is reduced more and more during repulsion, maintaining a large braking force despite the reduction in speed of the moving parts. .

The fluid reservoir 99 is advantageously housed in a sheath 103 closed by a cover 104, which is equipped, on the side opposite to said reservoir, with sealing means, in particular three seals, a seal 105, a fixed seal 106 and a scraper seal 107. The sealing seals are advantageously retained in their housing by means known per se such as elastic rings or screwed and glued assemblies. The plunger rod 95 is advantageously guided in a guide ring 109 with self-lubricating lining 110. This ring is advantageously disposed between the réser¬ see 99 and the seals 105, 107.

Said guide ring 109 is advantageously equipped with a protective skirt 113 which prevents the jets of fluid from damaging the self-lubricating ring 110 and / or the seals 105 and 107.

An air volume 102 is provided above the upper level of the fluid 101. Since the tank 99 is closed by the ring 109, the total volume occupied by the fluid 101 and the air 102 is constant. The penetration of the plunger rod 95 into the fluid 101 during the repulsion induces a corresponding rise in the level of the fluid 101 inside the tank 99, this rise being offset by the compression of the volume of air 102.

The reservoir 99 is, in the embodiment shown, consisting of a single piece. An advantageous alternative is to manufacture the tank in two parts, the part used for braking the plunger rod 95 being surmounted by a bracing ring.

According to a preferred embodiment, the plunger rod is made of a light alloy with high resistance treated on the surface at least on the part coming into contact with the self-lubricating ring and the seals 105 and 107. In the case of the example, an aluminum alloy treated by hard anodization was used.

The plunger rod 95 can be formed, in one piece with the repulsion disc 37 and / or with the tail 43. It is however also possible to provide an assembly, in particular a glued screw connection.

The sheath 103 in which the various elements are housed is advantageously introduced from below into the hyper-fast circuit breaker and fixed by a flange 115 on the external surface of the bottom cover 5.

It has also been noted from the shape of the parts that the sheath comprising in particular the reservoir with its full of fluid can possibly be introduced in a prone manner in the circuit breaker without the fluid being able to escape (ease of assembly, for example).

With reference to FIG. 3, another embodiment has been shown in which the plunger rod 95 integral with the repulsion disc 37 is of essentially straight cylindrical or rectangular shape and associated with a fluid reservoir 99 whose internal face is profiled by a curve constructed so that said tank is flattened up.

Claims

1. Hyper-fast circuit breaker assisted by a semiconductor control circuit, comprising a repulsion coil, a repulsion disc (37) associated with a contact bridge (39) carrying the movable contacts (41), said disc repulsion (37) collaborating with said repulsion coil (35), a contact retaining means in the closed state which exerts sufficient pressure to resist an imposed contact pressure and which is arranged liberally during the repulsion of the disc (37) under the effect of the repulsion coil (35), and a damping means (97), characterized in that said damping means (97) comprises a plunger rod (95) integral with the disc repulsion (37) and a reservoir (99) containing fluid intended to absorb the kinetic energy of the repulsion disc (37) - plunger rod (95) assembly during repulsion by the repulsion coil ( 35), by adapting the shapes of the plunger rod (95) and the re servoir (99) relative to each other so as to have fluid discharge sections varying according to the stroke of the plunger rod (95).

2. Hyper-fast circuit breaker according to claim 1, characterized in that the repulsion disc assembly (37) - plunger rod (95) is in one piece.

3. Hyper-fast circuit breaker according to any one of claims 1 and 2 characterized in that the tank

(99) has an essentially cylindrical or straight rectangular shape and the plunger rod (95) has a profiled end widening from the end.

4. Hyper-fast circuit breaker according to any one of claims 1 to 3 characterized in that the plunger rod (95) has a profiled end constituted by a succession of truncated cones having different coni¬ city angles, or by a continuous curve making it possible to obtain an essentially constant braking force.

5. Hyper-fast circuit breaker according to any one of claims 1 to 4 characterized in that the tank comprises a conical zone (100).

6. Hyper-fast circuit breaker according to any one claims 1 and 2 characterized in that the plunger rod (95) has an essentially straight cylindrical or rectangular shape and is associated with a fluid reservoir (99) whose internal face is profiled so that said reservoir is crushed towards the outlet .

7. Hyper-fast circuit breaker according to any one of claims 1 and 6 characterized in that the reservoir is profiled by a continuous curve making it possible to obtain an essentially constant braking force.

8. Hyper-fast circuit breaker according to any one of the preceding claims, characterized in that the repulsion disc (37) and the plunger rod (95) are made of a light material, in particular a high aluminum alloy. resistance.

9. Hyper-fast circuit breaker according to any one of the preceding claims, characterized in that the fluid reservoir (99) is housed in a sheath (103) equipped with sealing means, in particular a seal (105), a fixed seal (106) and a scraper seal (107).

10. Hyper-fast circuit breaker according to any one of the preceding claims, characterized in that the plunger rod (95) is guided in a self-lubricating guide ring (109, 110) preferably disposed between the reservoir (99) and the seals (105,107), said guide ring being preferably equipped with a protective skirt (113).

11. Hyper-fast circuit breaker according to any one of the preceding claims, characterized in that the plunger rod (95) is surface treated at least on the part coming into contact with the guide ring (109, 110) and the seals ( 105, 107).