FR2752329A1 - ROTATING AND EXPANSION ARC CIRCUIT BREAKER - Google Patents

Abstract

The invention relates to a rotating and expanding arc circuit breaker. This circuit breaker mainly comprises a sealed enclosure filled with a gas with high dielectric strength and containing per pole: an interrupting chamber (1) delimited by a substantially cylindrical casing (6) and closed by two bases (7, 8), a pair arcing contacts (2, 3), each passing through one of the aforementioned funds (7, 8), a coil for creating a magnetic field blowing in rotation of the arc, and a pair of main contacts ( 4, 5) arranged outside the interrupting chamber (1) and arranged to open before the separation of the arcing contacts (2, 3). One (7) of the funds (7, 8) is insulating, and the annular edge (9) forming a collar of said casing (6), adjacent to this insulating bottom (7), carries the movable main contact (5). The cylindrical casing (6) as well as the other (8) of the two bases (7, 8) are made of a conductive material, this conductive base (8) being coupled to the movable arcing contact (3) whose mechanism control cooperates with sequencing means (10) to establish the opening and closing sequences of the movable contacts (3, 5).

Description

ROTATING AND EXPANSION ARC CIRCUIT BREAKER

  The present invention relates to a circuit breaker of the type comprising a sealed chamber filled with a gas with high dielectric strength and containing one or more poles, each pole comprising: - a breaking chamber defined by a substantially cylindrical envelope of a closed manner in a manner sealed at both ends by means of funds, - a pair of arcing contacts, respectively a fixed arcing contact and a moving ar contact moved by a control mechanism, arranged coaxially in said breaking chamber and passing through each one of said bottoms, at least one of said contacts comprising gas flow conduits making it possible to make the arcing contacts communicate in a separate position, the interrupting chamber with said enclosure, which thus forms an expansion chamber, a coil or the like arranged inside the breaking chamber so as to create in the separation zone of the arc contacts a magnetic field of whistling in rotation of an arc drawn between the separate arc contacts, - a pair of main contacts, in parallel with the arcing contacts, arranged outside the interrupting chamber and arranged to open before the separation of the arcing contacts during an opening operation of the circuit breaker, said envelope and one of the abovementioned bottoms being made of a conductive material and electrically connected to the arcing contact associated with said bottom, while the other bottom is an insulating material and forms an insulator providing electrical insulation in the open position of the contacts, the end of

  said envelope adjacent to the insulating bottom carrying one of the main contacts.

  There is known a rotating arc circuit breaker and expansion of the kind mentioned above, and as described in the patent FR 2,617,633 of the Applicant, wherein the aforementioned insulating base of the arc chute is traversed by the moving arc contact sliding, which cooperates with a fixed arc contact through the metal bottom to which it is connected

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  electrically. In this device, the insulating bottom is placed at the bottom of the

  breaking chamber and is away from the cutoff area.

  However, a disadvantage of this circuit breaker is that the dusts (metal powders etc ...) generated during the cut, mainly strong currents, come under the effect of gravity on the insulating bottom and decrease from this. makes his

dielectric characteristics.

  The present invention solves this problem and proposes an easy-to-use rotating and expansion arc circuit breaker improving the dielectric characteristics of the bottom

  insulation while facilitating the breaking of small currents.

  For this purpose, the subject of the present invention is a circuit breaker of the kind mentioned above, characterized in that the aforementioned insulator is placed at the top of the chamber of

  cut so as not to be reached by the dust generated during the cut.

  According to a particular embodiment, the annular edge of the envelope adjacent to the insulating bottom carries the movable main arc contact and the aforementioned conductive bottom is coupled to the movable arcing contact whose control mechanism cooperates with sequencing means.

  establishing the appropriate opening and closing sequences of the moving contacts.

  According to a particular characteristic, the aforementioned insulator is placed above the piece of

  contact of the arc contact associated with the upper bottom of the breaking chamber.

  According to another feature, the outer diameter of the moving arc contact is greater

  to the outside diameter of the fixed arc contact.

  According to another characteristic, it comprises a means for uncoupling the envelope

  mentioned above of the insulator, after the separation of the arcing contacts, once the cut is made.

  According to another characteristic, the insulator, or insulating base, of the breaking chamber is traversed by the fixed arcing contact, which cooperates with the moving arcing contact passing through the

  conductive bottom to which it is electrically and mechanically connected.

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  Advantageously, it comprises an electromagnetic coil for rotating the arc

  arranged coaxially around the fixed arc contact, the insulator being placed behind the coil.

  Advantageously, the moving arc contact is hollow. Advantageously, the chamber is filled with sulfur hexafluoride under pressure

atmospheric or under pressure.

  But other advantages and features of the invention will appear better in the

  detailed description which follows and refers to the accompanying drawing given solely for

  and in which: - The single figure is a schematic axial sectional view of a circuit breaker according to the invention, the half-section on the right representing the circuit breaker in the open position and the

  left half-cut in closed position.

  In the single figure, we see a breaking chamber 1 belonging to one of the poles of a self-expanding circuit breaker and medium or high voltage arc. This chamber 1 encloses two arcing contacts 2, 3 respectively fixed and movable, and is intended to be housed inside a sealed enclosure (not shown) filled with a gas with high dielectric strength, in particular the Sulfur hexafluoride at atmospheric pressure or at overpressure. This chamber also has two main contacts 4.5 mounted in

  parallel with the above-mentioned arc contacts 2, 3 outside the breaking chamber 1.

  This cut-off chamber 1 is confined by a cylindrical envelope 6, closed at its two opposite ends by two bottoms 7, 8. The two aforementioned fixed and mobile contacts 2, 3, respectively, are mounted coaxially inside the said chamber 1 and through respectively the two funds 7, 8. The cylindrical casing 6 and one 8 of the two funds 7, 8, through which the movable contact 3, are metallic. The opposite bottom 7 is penetrated in a sealed manner by the fixed contact 2 and is made of an insulating material so

  to ensure the electrical insulation between the fixed contact 2 and the cylindrical envelope 6.

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  Inside the contact piece 2a of the fixed arcing contact 2 is mounted an arc-blowing coil, not shown, which is capped in known manner with an electrode 11 (not shown) constituting a migration track. of the arc and disposed opposite the movable arcing contact 3. The insulating part 7, or insulator, is placed behind this coil and therefore, at the top

of the breaking chamber 1.

  The two arcing contacts 2, 3 are electrically connected, respectively, to two current supply pads generally formed by the two bottoms (not shown) of

the aforementioned enclosure.

  The movable arc contact 3 is constituted by a hollow tube making it possible to communicate, in the open position of the circuit-breaker shown on the right-hand part of the figure, the breaking chamber 1 with the enclosure, which constitutes a chamber of expansion, thanks to the presence at the base of the movable contact 3 communication ports (not shown) between the tubular interior of the contact 3 and the enclosure. Note that this communication can also be performed through the fixed arc contact 2, which can also be

hollow.

  The cylindrical casing 6 of the interrupting chamber 1 extends in projection of the insulating bottom 7 by a collar 9 arranged in main movable contact 5 intended to cooperate with the main fixed contact 4 of the circuit breaker. At the opposite end of the envelope 6, the metal base 8 is electrically connected and mechanically coupled to the movable arcing contact 3 so that the appropriate opening and closing sequences of the movable contacts 3, 5 are realized. . For this purpose, the control mechanism of the movable contact 3 (not shown) cooperates with sequencing means 10 provided between the

  metal bottom 8 and the movable bow contact 3.

  Advantageously, will also be provided means for uncoupling the envelope 6 of

  the insulator 7, once the cut made.

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  The operation of the circuit breaker according to the invention is apparent from the preceding description and will be briefly described in the following: In the closed position of the circuit breaker shown in the left half-view of the single figure, the permanent current passes through the contact mobile 3, the metal bottom 8, then the cylindrical casing 6, then the main contacts 4, 5. A small fraction of the current flows through a parallel circuit formed by the moving arc contact 3, the electrode, the coil

  fixed contact 2 and the conductive bottom of the enclosure (not shown).

  The opening of the circuit breaker is controlled by a sliding down of a control rod (not shown) driving the tubular support 3b of the movable arcing contact 3 and

  thereby the cylindrical casing 6 carrying the movable main contact 5.

  During a first phase of the opening movement of the circuit breaker, the main contacts 4, 5 open while the contact piece 3a of the movable arcing contact 3 remains abutted with the electrode of the fixed arcing contact 2 thanks to the presence of the sequencing means 10. As soon as the main contacts 4, 5 are separated, the current is switched in the parallel circuit formed by the moving arcing contact 3, the coil and the arcing contact.

fixed 2.

  It will be noted that the movement of the envelope 6 then generates a general movement of the

  gas that facilitates the breaking of small currents.

  In addition, in the case where the outer diameter of the movable contact 3 is greater than the outside diameter of the fixed contact 2, the movement of the expansion gas during the pre-stroke creates a

  light pistons also favoring the breaking of small currents.

  The opening of the main contacts 4, 5 takes place without arc formation, and as soon as the current is switched in the parallel circuit, the coil generates a magnetic field which blows the arc which forms during the separation of the contacts. arc 2, 3 during the continued movement of opening the circuit breaker. The arch shot in the break chamber 1

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  causes a heating and a rise in pressure of the gas contained in this chamber 1 which gas escapes through the tubular movable contact 3 to the expansion chamber constituted by the chamber, by pneumatically blowing the arc extending between the contact

mobile arc 3 and the electrode 11.

  Thus, thanks to the invention, the dust generated during the cut fall, by gravity, on the metal base 8 and do not reach the insulating bottom 7, which thus has a good

dielectric strength.

  During a continued movement of the envelope 6, once the arc contacts 2, 3 separated and the cut made, said envelope 6 will be advantageously disconnected from the insulator 7, in order to avoid having, at length of time an insulator 7 energized when

the circuit breaker is open.

  Note that the invention can of course be used for all the poles of a circuit breaker to

  multipolar selfexpansion, having for example a common speaker at all poles.

  Of course, the invention is not limited to the embodiment described and illustrated which has not

been given as an example.

  On the contrary, the invention includes all the technical equivalents of the means thus described.

  that their combinations if they are carried out according to his spirit.

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Claims (9)

  1. Circuit breaker of the kind comprising a sealed enclosure filled with a gas with high dielectric strength and closing one or more poles, each pole comprising: - a breaking chamber defined by a substantially cylindrical envelope sealed in a sealed manner to its two ends by funds, - a pair of arcing contacts, respectively a fixed arc contact and a movable arc contact mu by a control mechanism, arranged coaxially in said breaking chamber and each passing through one said bottoms, at least one of said contacts having gas flow conduits for communicating in separate position the arcing contacts, the interrupting chamber with said enclosure, which thereby forms an expansion chamber; coil or the like arranged inside the interrupting chamber so as to create in the separation zone of the arc contacts a magnetic field for blowing in rotation of an arc. between the separate arc contacts, - a pair of main contacts, in parallel with the arcing contacts, arranged outside the interrupting chamber and arranged to open before the separation of the arcing contacts during an opening operation of the circuit breaker, said envelope and one of the abovementioned funds being made of a conductive material and electrically connected to the arc contact associated with said bottom, while the other bottom is made of an insulating material and forms an insulator providing electrical insulation in the open position of the contacts, the end of said envelope adjacent to the insulating bottom carrying one of the main contacts, characterized in that the aforementioned insulator (7) is placed at the top of the breaking chamber (1)   so as not to be affected by the dust generated during the cut.   2. Circuit breaker according to claim 1, characterized in that the annular edge (9) of the envelope (6) adjacent to the insulating base (7) carries the movable main arc contact (5), and 8 2752329   the aforesaid conductive bottom (8) is coupled to the movable arcing contact (3) whose control mechanism cooperates with sequencing means (10) establishing the   appropriate opening and closing sequences of the movable contacts (3,5).   3. Circuit breaker according to claim 1 or 2, characterized in that the aforementioned insulator (7) is placed above the contact piece (2a) of the arc contact (2) associated with the bottom   upper (7) of the interrupting chamber (1).   4. Circuit breaker according to any one of claims 1 to 3, characterized in that the   1o outer diameter of the movable arc contact (3) is greater than the outside diameter of the contact fixed arc (2).   5. Circuit breaker according to any one of claims 1 to 4, characterized in that   comprises means for uncoupling said casing (6) from the insulator (7), after the   separation of the arcing contacts (2,3) once the cut is made.   6. Circuit breaker according to any one of claims 1 to 5 characterized in that   the isolator (7), or insulating bottom, of the breaking chamber (1) is traversed by the fixed arc contact (2), which cooperates with the movable arc contact (3) passing through the bottom   conductor (8) to which it is electrically and mechanically connected.   7. Circuit breaker according to any one of the preceding claims, characterized in that   it comprises an electromagnetic coil for rotating the arranged arc   coaxially around the fixed arc contact (2), the insulator (7) being placed behind the coil.   8 - Circuit breaker according to any one of the preceding claims, characterized in that   the moving arc contact (3) is hollow.   9. Circuit breaker according to any one of the preceding claims, characterized in that   the chamber is filled with sulfur hexafluoride at atmospheric pressure or under overpressure.