FR2762710A1 - ELECTRICAL SHUTDOWN DEVICE FOR LOW AND HIGH VOLTAGE - Google Patents

Abstract

The circuit breaker construction has an outer fixed section (10) with two contacts (30,40). there is a central moving contact (50) which can move between a closed position, contacting the fixed contacts and an open position. Alongside each fixed contact there is a magnetic field source (60). The field source elongates the arc formed on switching transversally to the direction of movement of the moving contact.

Description

The present invention relates to the field of devices for

  electric cut for high voltage.

  The invention applies in particular, but not limited to the high voltage areas MV (alternating from 1,000 to 50,000 volts and continuously from 1,500 to 75,000 volts) and HTB (alternating greater than

  000 volts and continuously greater than 75,000 volts).

  The present invention can also find application in the field of low voltages BTA (from 50 to 500 V in alternating mode and from 120 to 750V in continuous) and BTB (from 500 to 1000 V in alternating mode and from 750 to 1500 V in

continued).

  More specifically, the present invention relates to the field of electrical cut-off devices comprising a housing defining at least one chamber which houses two fixed contacts cooperating with a rotary movable contact moved at least between two positions: a closed position in which the rotary contact connects the fixed contacts, and an open position in which the movable contact is separated from the fixed contacts. Examples of such devices are found.

  known electrical cutout with rotary movable contact in DE- documents

  1088583, DE-612712, US-4700028 and US-3646284.

  To improve the breaking powers of such devices, we have

  already proposed various means of arc extinction.

  In particular, systems have been proposed for blowing arcs developed between the fixed and movable contacts by means of sets of pistons actuated by the rotary movable contact. Examples of such structures can be found in documents DE-677956, EP-23298, DE-2037777,

US-2100753 and FR-2019739.

  It has also been proposed to add magnets in such electrical breaking devices to lengthen the arcs and improve the breaking powers. Examples of the realization of such structures

  will be found in document EP-0296915.

  The present invention now aims to improve

  known low or high voltage cut-off devices.

  This object is achieved in the context of the present invention, thanks to an electrical cut-off device of the known type comprising a housing defining at least one chamber which houses two fixed contacts and a movable rotary contact displaceable between at least two positions: a position of closure in which the rotary mobile contact connects the two fixed contacts and an open position in which the rotary mobile contact is separated from the fixed contacts and at least one source of magnetic field adapted to lengthen the arc developed between at least one fixed contacts and the movable contact during an opening phase, characterized in that it comprises at least one source of magnetic field arranged to generate an arc development in one direction

  axial with reference to the axis of rotation of the movable contact.

  Other characteristics, aims and advantages of the invention

  will appear on reading the detailed description which follows, and

  look at the accompanying drawings, given by way of non-limiting example and in which: - Figure 1 shows a schematic cross-sectional view of a cut-off device according to the present invention in the closed position, - Figure 2 shows a view of the same device during an opening phase, and - Figure 3 shows a view of the same device in a position of

earth connection.

  We can see in the appended figures, an electrical cut-off device comprising a box 10 formed of two shells 12, 14 assembled by any suitable means, for example by screwing or bolting at 15. Preferably, a seal 16 is interposed between the two shells 12, 14. The geometry of the shells 12, 14 can be the subject of numerous variant embodiments. These shells 12, 14 define in combination an internal chamber 20. According to the representation given in the appended figures, the chamber 20 is at

  less partially cylindrical of revolution centered on an axis O-O.

  This geometry is not limiting.

  The shells 12, 14 support two fixed contacts 30, 40, electrically conductive passing through the shells to be accessible, on the one hand outside the housing 10 for an electrical connection, and on the other hand on the inside of chamber 20. Inside chamber 20, the two fixed contacts are diametrically opposed by

relative to axis 0-0.

  As can be seen in the appended figures, if necessary, one of the contacts 30 can be extended inside the chamber 20 by a sector 32 of electrically conductive material in the form of a sector.

crown centered on the axis 0-0.

  The chamber 20 also houses an electrically conductive rotary movable contact 50 capable of rotation about the axis 0-0. The

  rotary movable contact 50 is actuated in rotation by any suitable means.

  It is formed by a straight bar which extends along a diameter by

relative to axis 0-0.

  The rotary movable contact 50 is thus displaced between at least two positions: a closed position as illustrated in FIG. 1 in which the rotary movable contact 50 provides a connection between the fixed contacts 30, 40 and an open position illustrated in FIG. 2 in which the movable contact 50 is separated from the contacts 30, 40 and opens

  thus the electrical circuit between them.

  The contacting cooperation defined between the ends of the rotary movable contact 50 and the fixed contacts 30, 40 can be the subject of numerous embodiments. According to the schematic representation given in the appended figures, the fixed contacts 30, 40 are formed of knives, while the cooperating ends of the rotary movable contact are formed of complementary clamps. The reverse arrangement can however be retained. Thus, provision can be made to make the fixed contacts 30, 40 in the form of pliers and the cooperating ends of the rotary movable contact 50 in the form of knives. Preferably, these elements 30,, 50 are adapted to define multiple contacts at the level of each

30/50 and 40/50 torque.

  Those skilled in the art will readily understand that during the opening phase, an arc A of generally peripheral orientation develops between the ends of the rotary movable contact 50 and each of the fixed contacts 30, 40, as illustrated in the figure. 2. In FIG. 2, the current generating the arcs A is referenced I. In the context of the present invention, there are provided magnetic field sources 60 adapted to develop the arc in an axial direction, that is to say -display parallel to the axis OO of rotation of the rotary contact 50. For this, the sources 60 have an orientation of

  radial field with reference to the O-O axis.

  According to the embodiment illustrated in the appended figures, the sources 60 are formed of magnets. However, as a variant, the sources 60 could be formed from electromagnetic coils supplied

  electrically at least during the opening phase.

  More precisely still, according to the embodiment illustrated in the appended figures, the magnets 60 are housed in the shells 12, 14, near the fixed contacts 30, 40, that is to say facing the zone in

which appears the arc.

  More precisely according to the appended figures, the magnets are embedded in the shells 12, 14. They are thus covered by a veil coming

  of material of the shells 12, 14 or added, which protect them from the arcs.

  As a variant, however, the magnets 60 can be flush with the internal surface of the chamber 20, or protrude internally by

  relative to this surface in chamber 20.

  According to yet another variant, the magnets 60 can be placed on the outside of the shells 12, 14. This arrangement facilitates possible maintenance and replacement operations for these magnets

, or even adjustment if necessary.

  The two magnets 60 (or equivalent coils) may have opposite poles directed towards the axis of rotation OO of the movable contact 50, as illustrated in FIGS. 1 to 3. In this case, the arcs A are extended axially in the same direction . The direction of the magnets illustrated on the

  appended figures is of course not limiting.

  As a variant, the two magnets 60 (or equivalent coils) could have identical poles directed towards the axis OO of rotation of the movable contact 50. In this case, the arcs generated respectively near the fixed contacts 30, 40 are extended in opposite directions

parallel to the axis O-O.

  It will also be noted that in the context of the invention, although this is not compulsory, the shell 14 further supports a

  second fixed contact 42 connected to earth.

  Thus, as illustrated in FIG. 3, when the rotary movable contact 50 reaches the contact 42, it connects the sector 32 and this contact 42 and consequently makes it possible to connect the fixed contact 30 connected to the sector 32, to earth. The magnets 60 can be fixed on the shells 12, 14 by any suitable means. The use of magnets 60 (or equivalent coils) of radial orientation makes it possible to produce a box of reduced transverse dimensions, consequently reducing the quantity of material

  necessary and reduce the overall cost of the device.

  In practice, the present invention is preferably used in the form of three chambers juxtaposed axially corresponding to the three phases of an electrical distribution network. The distances required between supply lines of a three-phase network are compatible with the axial dimensions required to allow the development of the arc thanks to the magnets 60. These three chambers can be formed of a

  single box or if necessary three juxtaposed boxes.

  The axial direction in which the arc is extended depends on the direction of the breaking current. For this reason, the assembly formed by the fixed contacts 30, 40, the rotary movable contact 50 and the magnets 60 (generally coplanar with each other and centered on a plane transverse to the axis of rotation OO), is preferably placed in middle position of the chamber to allow the arcs to be extended either in one direction or

  in the other according to the direction of the current.

  Of course the present invention is not limited to the particular embodiment which has just been described, but extends to any variant

conforms to his spirit.

  Thus, by way of example, it is possible, if necessary, to envisage making the cut-off device using a single magnet 60 (or equivalent coil) and not using two magnets 60 (or equivalent coils) ) respectively disposed near each fixed contact, 40 facing the arc generation zone during the phase

  opening as illustrated in Figures 1 to 3 attached.

Claims (15)

  1. Electric cut-off device, in particular for low or high voltage, comprising a box (10) defining at least one chamber (20) which houses two fixed contacts (30, 40) and a rotary movable contact (50) capable of displacement at less between two positions: a closed position in which the movable contact (50) connects the two fixed contacts (30, 40) and an open position in which the movable contact (50) is separated from the fixed contacts (30, 40 ), and at least one magnetic field source (60) adapted to lengthen the arc appearing between the movable contact (50) and at least one of the fixed contacts (30, 40) during the opening phase, characterized by the fact that the magnetic field source (60) is adapted to lengthen the arc axially with reference to the axis of rotation (OO) of the movable contact (50).   2. Device according to claim 1, characterized in that   the magnetic field source (60) is formed of a magnet.   3. Device according to claim 1, characterized in that the magnetic field source (60) is formed of a coil electromagnetic.   4. Device according to one of claims 1 to 3, characterized by   the fact that the magnetic field source defines a field of radial orientation.   5. Device according to one of claims 1 to 4, characterized by   the fact that it comprises two sources of magnetic field (60) disposed respectively near the fixed contacts (30, 40) and adapted to axially lengthen the arcs arising respectively between the contact   mobile (50) and each of the fixed contacts (30, 40).   6. Device according to claim S, characterized in that the two sources (60) have identical poles directed towards the axis of rotation (O-O) of the movable contact (50).   7. Device according to claim S, characterized in that   the two sources (60) have opposite poles directed towards the axis of rotation (O- O) of the movable contact (50).   8. Device according to one of claims 1 to 7, characterized by   the fact that at least one source (60) is embedded in the component material the housing (10).   9. Device according to one of claims i to 7, characterized by   the fact that at least one source (60) is exposed on the internal surface of the chamber (20).   10. Device according to one of claims 1 to 7, characterized   by the fact that at least one source (60) projects inside the room (20).   11. Device according to one of claims 1 to 7, characterized   by the fact that at least one source (60) is disposed on the outside of the housing (10).   12. Device according to one of claims 1 to 11, characterized   by the fact that each source of magnetic field (60) is arranged in the wall of the housing (10) facing the area adjacent to the fixed contacts   on which the arch develops during the opening phase.   13. Device according to one of claims 1 to 12, characterized   by the fact that it further comprises a third fixed contact (42) connected to earth and an electrically conductive sector (32) connected to one of the main fixed contacts (30) for connecting the latter to earth by   via the movable contact (50) during opening.   14. Device according to one of claims 1 to 13, characterized   by the fact that the assembly formed by the fixed contacts (30, 40), the movable contact (50) and at least one source (60) is placed in the middle position in the room (20).   15. Electric cut-off device, characterized in that it comprises three juxtaposed chambers (20) each housing two fixed contacts (30, 40), a movable contact (50) and at least one field source   magnetic, according to one of claims 1 to 14.