Title of Invention | AN ARC QUENCHING SYSTEM FOR A SWITCHING DEVICE |
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Abstract | The invention relates to an arc quenching system for a switching device (1), having an arc guide rail (7) which comprises a fixed contact (5) associated with a moving contact (6), and having an additional arc guide rail (10) at a spacing therefrom, which rails are intended for guiding of an arc (11) into an arcing chamber (8) arranged between the arc guide rails (7, 10) and absorbing the arc (11), and having a current conductor path (13) which comprises an electrically conductive passage to the additional arc guide rail (10) in the manner of a conductor loop (10, 13) and is electrically insulated from the fixed contact (5), wherein the conductor loop (10, 13), without touching the fixed contact (5), is arranged in a region of an interrupting chamber (12) defined by the switching contact pair (5,6) and by the two arc guide rails (7, 10) in such a way that a current (1) driving the arc (11) into the arcing chamber (8) is guided across the current conducting path (13) only when the arc (11) commutates from the moving contact (6) to the additional arc guide rail (10). |
Full Text | FIELD OF INVENTION The invention relates to an arc-quenching apparatus for a switching device. BACKGROUND OF INVENTION Such an arc-quenching apparatus is used for interrupting or quenching an arc which is produced when a pair of contact pieces, through which current flows, is opened. When the contact pieces are separated, the current flows via regions, which are becoming ever smaller, of an associated contact zone and heats up these regions to an ever greater extent. Shortly before the actual separation of the contact pieces, a fused link is produced which ultimately breaks off in the event of low currents or vaporizes in the event of high currents. Accordingly, the current can only continue to flow via an arc in the form of a conducting plasma column. The strength of the arc is in this case influenced by the level and type of connected current. In the event of a short circuit in a circuit which is protected by a circuit breaker, short circuit currents of up to 15 000 A result, for example. In this case, the arc produces temperatures of up to 20 000 K in the switch housing over its life in dependence on a DC or AC supply. The high thermal load results in damaging effects for the switch components, however. For example, metal and insulating parts can be damaged or destroyed by the effect of the arc. Consequently, it is necessary to cause the arc to be quenched as quickly as possible in order to minimize the thermal energy conversion. DE 35 01 314 Al has disclosed a multi-pole circuit breaker, which is provided with a blowing loop for the purpose of delivering the arc run in a power supply to a contact; the blowing loop is formed by a feed line being connected to an arc guide rail, downstream of a fixed contact piece when viewed in the direction of the arc run, said arc guide rail having the fixed contact piece. However, the operating current of a circuit flows permanently through the blowing loop, which results in an increased power loss and thus also in increased heating of the circuit breaker. More severe heating firstly requires materials to be used which are more thermally stable and are more cost intensive and secondly requires the thermal release to be matched such that it can compensate for the intrinsic heating owing to the correspondingly larger dimensions of the tripping path. A circuit breaker having an additional blowing loop is disclosed in EP 0 009 156 Al. The circuit breaker is in this case provided with a contact arrangement forming a blowing loop and an arcing chamber, which is provided with parallel arc splitter plates, which are arranged at an angle with respect to the blowing loop, and is provided with arc guide rails. One of the arc guide rails flanks the arc splitter stack on one side and, in front of the arc splitter plates in the running region of the arc, a conductor piece, which is associated with an additional blowing loop, is provided parallel to it. The additional blowing loop, however, is accommodated in a free space behind one arc guide rail in a circuit which is disconnected during normal operation. In addition, that part of the arc guide rail which faces the contact arrangement and is used for deflecting the arc, protrudes into the region of the open position of the moveable contact piece, with the result that the connection of the additional blowing loop only takes place when the arc arcs over from the moveable contact piece to the arc guide rail. DE 195 18 051 Al has disclosed an arc-quenching device, in which the quenching action is assisted by a magnetic blowing field, which can be produced with the aid of a blowing device. Such a blowing device or blowing coil can be arranged on one or even on both sides of the overall chamber region, but continuously has the switch current flowing through it. OBJECT OF INVENTION It is the object of the present invention to specify an arc quenching apparatus which ensures rapid quenching of an arc using simple means with little intrinsic heating. SUMMARY OF INVENTION This object is achieved according to the features of the invention. Advantageous embodiments are in each case described and defined hereinafter. A current conductor track, which has an electrically conductive junction with the further arc guide rail in the form of a conductor loop and is electrically insulated from a switching contact pair, makes it possible, owing to a connection-free arrangement of the conductor loop with respect to the switching contact pair in the region of a switching chamber, for a current, which drives the arc into the arc-quenching chamber, to be guided via the current conductor track when an arc has commutated from one of the switching contacts to the further arc guide rail; in this case, use can be made of a physical functional principle, in accordance with which conductors with current flowing in opposite directions - in this case a first region of the current conductor track and the arc - repel one another and conductors with current flowing in the same direction - in this case a second region of the current conductor track and the arc - attract one another. in an increased arc acceleration in the direction of the arc-quenching chamber. Since current is only flowing through the conductor loop in the event of a fault brought about by an overload or a short circuit in the course of the commutation process, during normal operation a low internal resistance and a low power loss of the switching device also result, in addition to a short current path. In the event of a fault, a longer current path, a greater internal resistance and a corresponding current limitation come to bear, with the result that reliable and rapid quenching of the arc is achieved. Furthermore, a comparatively long life for a switching device having the arc-quenching apparatus is achieved using simple and space-saving means. A current conductor track is advantageously arranged on the further arc guide rail on both sides of the switching contact pair, with the result that the driving effect on the arc brought about by the current is increased with little material being used. Correspondingly, in each case one conductor loop can also be arranged on both sides of the switching contact pair, said conductor loops being electrically conductively connected at least at one loop end. The conductor loop is preferably matched in terms of shape and position to a switching chamber, in which case effective use of space is ensured in the sense of a long effective conductor length. The conductor loop advantageously reaches into a region of the switching contact pair, as a result of which the effective conductor length, in particular of a first and a second subregion of the conductor loop, is likewise lengthened. The two subregions in this case each have, per se, an essentially parallel position with respect to the arc, with the result that there is an optimum force effect of the magnetic fields influencing one another. On the basis of the loop geometry and the arc run, repulsion forces and attraction forces thus act together on the arc and result below with reference to exemplary embodiments illustrated in the accompanying drawings without the invention being restricted in this manner; in the drawing: Figure 1 shows a detail of a switching device having a closed switching contact pair and an arc-quenching chamber, and Figure 2 shows a detail of the switching device shown in figure 1 with an open switching contact pair. Figure 1 shows a detail of a switching device 1 having an arc-quenching apparatus, which has a schematically illustrated housing 2. In this case, the switching device 1 is in the form of a circuit breaker and comprises, inter alia and in addition to an electromagnetic release 3, a thermal release 4 and a switching contact pair having a fixed contact 5 and a moving contact 6. The fixed contact 5 is placed on an arc guide rail 7, which acts as the contact carrier and at the same time has an electrically conductive connection to a coil of the electromagnetic release 3. For its part, the coil leads to a schematically illustrated connection terminal. On the free-end side, the arc guide rail 7 passes via a yoke connected thereto into an arc-quenching chamber 8. The arc guide rail 7 is in the form of a lug in the region after the fixed contact 5, toward the arc-quenching chamber 8. The moving contact 6 is fixed on a moveable contact arm 9, which is mounted such that it can move in rotary fashion about an axis (not illustrated here). Both the electromagnetic release 3 and the thermal release 4 - in this case a bimetallic strip - can cause the moveable contact arm 9 to pivot, depending on the fault case. In addition to the arc guide rail 7, a further arc guide rail 10 is provided which is spaced apart therefrom, said arc guide rail having the arc-quenching chamber 8 in their region on the free-end side. The two arc guide rails 7,10. below with reference to exemplary embodiments illustrated in the drawing, without the invention being restricted in this manner; in the drawing: figure 1 shows a detail of a switching device having a closed switching contact pair and an arc-quenching chamber as claimed in patent claim 1, and figure 2 shows a detail of the switching device shown in figure 1 with an open switching contact pair. Figure 1 shows a detail of a switching device 1 having an arc-quenching apparatus, which has a schematically illustrated housing 2. In this case, the switching device 1 is in the form of a circuit breaker and comprises, inter alia and in addition to an electromagnetic release 3, a thermal release 4 and a switching contact pair having a fixed contact 5 and a moving contact 6. The fixed contact 5 is placed on an arc guide rail 7, which acts as the contact carrier and at the same time has an electrically conductive connection to a coil of the electromagnetic release 3. For its part, the coil leads to a schematically illustrated connection terminal. On the free-end side, the arc guide rail 7 passes via a connected yoke into an arc-quenching chamber 8. The arc guide rail 7 is in the form of a lug in the region after the fixed contact 5, toward the arc-quenching chamber 8. The moving contact 6 is fixed on a moveable contact arm 9, which is mounted such that it can move in rotary fashion about an axis (not illustrated here) . Both the electromagnetic release 3 and the thermal release 4 - in this case a bimetallic strip - can cause the moveable contact arm 9 to pivot, depending on the fault case. In addition to the arc guide rail 7, a further arc guide rail 10 is provided which is spaced apart therefrom, said arc guide rails having the arc-quenching chamber 8 in their region on the free-end side. The two arc guide rails 7, 10 arranged in the form of a funnel are used together for guiding an arc 11 in a targeted manner, as shown in figure 2, into the arc-quenching chamber 8 accommodating the arc 11. The region which is defined by the switching contact pair 5, 6 and the two arc guide rails 7, 10 as well as possibly by an arc entry zone of the arc-quenching chamber 8, is referred to as the switching chamber or prechamber 12. The switching chamber 12 has, inter alia, a current conductor track 13, which is provided with a first, second and third subregion 13a, 13b and 13c. The current conductor track 13 has an electrically conductive junction with the further arc guide rail 10 in the form of a conductor loop 10, 13 in its first subregion 13a. In this case, the conductor loop 10, 13 is matched in terms of shape and position to the contours of the switching chamber 12 and may possibly be drawn, with the second subregion 13b, partially behind the arc-quenching chamber 8. In addition to the conventional materials, such as copper, aluminum or steel, for the conductor loop 10, 13, said conductor loop may be in the form of a stamped, bent part or in the form of a flat ribbon bent part or in the form of a wire shaped part. The conductor loop 10, 13 is connected at the junction shown in figure 1 by means of one of several conventional joining methods, although the junction may also be of integral design. The conductor loop 10, 13 protrudes in a connection-free manner, i.e. without contact being made with the arc guide rail 7 or the moveable contact arm 9 including their contacts 5 and 6, respectively, into the region of the switching contact pair 5, 6. No contact is made with the conductor loop 10, 13 at its point of intersection, either. The current conductor track 13 as part of the conductor loop 10, 13 accordingly runs behind the switching contact pair 5, 6, set back in relation to the plane of the drawing in figure 1. It is of course also possible for such a current conductor track 13 to be arranged on the further arc guide rail 10 on both sides of the switching contact pair 5, 6. In correspondence to the arrangement illustrated by dashed lines in figure 1, the additional current conductor track runs above the switching contact pair 5, 6 in relation to the plane of the drawing. Furthermore, a further variant embodiment is possible, in which in each case a complete conductor loop 10, 13 is provided on both sides of the switching contact pair 5, 6. The two conductor loops 10, 13 are in this case electrically conductively connected at one loop end, which leads to a further connection terminal. As shown in figure 1, the current I, which is symbolized by an arrow, is fed in at the connection terminal. The current I flows through the coil of the electromagnetic release 3 via a subregion of the arc guide rail 7 up to the contact zone of the switching contact pair 5, 6 and, from there, via the moveable contact arm 9 further via a litz wire to the thermal release 4 and finally to the further connection terminal, to which a load can be connected. During normal operation of the switching device 1, i.e. when the switching contact pair 5, 6 is closed, the current flow does not pass via the conductor loop 10, 13, with the result that it is also possible to profit from a low internal resistance and from a low power loss of the switching device 1, in addition to a short current path. In addition to the embodiment as a circuit breaker, the switching device 1 may also be in the form of a power breaker or a contactor, for example. Figure 2 shows a detail of the switching device 1 shown in figure 1 with the switching contact pair 5, 6 open. The contact position shown here corresponds to a tripping case or else a fault case, in which a short-circuit current or overload current flows. The current flow initially corresponds to that shown in figure 1, up to the switching contact pair 5, 6. When the contact pieces 5, 6 separate, the current flows via regions, which are becoming ever smaller, of an associated contact zone and heats up these regions to an ever greater extent. Shortly before the actual separation of the contact pieces 5, 6, a fused link is produced which ultimately breaks off in the event of low currents or vaporizes in the event of high currents. The current I therefore continues to flow via the arc 11 in the form of a conducting plasma column. Since the moving contact 6 of the moveable contact arm 9 is removed from the fixed contact 5, but the arc strives to counteract an extension owing to its arcing property, in order not to break off, the arc 11 is commutated - as is symbolized by the curved arrow - from the moving contact 6 to the conductor loop 10, 13, in particular to the further arc guide rail 10. In the process, the arc follows the physical principle of choosing the path of least resistance and arcs over to the potential of the conductor loop 10, 13. The current conductor track 13 is equipped with an insulating means, such as an insulating plate 14 as shown in figures 1 and 2 or an insulating housing part, in order to counteract the commutation of the arc 11 from the moving contact 6 to the current conductor track 13. The insulating plate 14 essentially extends over the first and second subregions 13a and 13b of the current conductor track 13. If appropriate, the insulating plate 14 can be passed as far as over the third subregion 13c of the current conductor track 13. It is also possible to envisage covering of the junction between the further arc guide rail 10 and the current conductor track 13 so as to deflect the arc 11 next to the junction, toward the further arc guide rail 10. The insulating means can also accordingly be provided for the additional current conductor track. Once the arc 11 has been commutated, over its life the conductor loop 10, 13 is connected in series between the two connection terminals in the current path for a few milliseconds. The total current I, which is brought about by an overload or a short circuit, accordingly only flows via the conductor loop 10, 13 after commutation. As a result, there is a significant reduction in the heating of the switching device 1, with the result that lower demands can be placed on the thermal release 4 with respect to compensation of the intrinsic heating. In this context, the use of more favorable materials with a lower conductance value, such as steel instead of copper for the conductor loop 10, 13, also has a cost-saving effect. Owing to the arrangement of the conductor loop 10, 13 essentially in the zone of the switching chamber 12, the arc 11 is magnetically influenced in the sense of the magnetic field being focused or deflected. The current flow direction in the first subregion 13a of the conductor loop 10, 13 is opposite to that of the arc 11. Conductors with current flowing in opposite directions - in this case the arc 11 and the first subregion 13a - have mutually repulsive magnetic fields, as a result of which the arc 11 is pushed in the direction of the arc- quenching chamber 8 between the two arc guide rails 7, 10, since the conductor loop 10, 13 is designed to be stationary and inflexible. In addition, the- current flow direction in the second subregion 13b of the conductor loop 10, 13 is in the same direction as that of the arc 11. Conductors with current flowing in the same direction - in this case the arc 11 and the second subregion 13b - have mutually attracting magnetic fields, as a result of which the arc 11 is drawn in the direction of the arc-quenching chamber 8 between the two arc guide rails 7, 10 owing to the stationary and inflexible conductor loop 10, 13. These effects, which are brought about by the force F owing to the arcuate subregions 13a and 13b, take place suddenly after commutation of the arc. In this case, in addition to the repulsion forces, attraction forces also act on the arc 11, these attraction forces also forcing it in the direction of the arc-quenching chamber owing to its intrinsic dynamics and thus assisting rapid entry and quenching. The arc 11 is severely accelerated in terms of its movement since the total overload or short-circuit current flows via the conductor loop 10, 13 before it ultimately reaches the further connection terminal to a load (not illustrated here) via the third subregion 13c. The higher the current in the event of a fault, the greater the force driving the arc. A comparatively long current path produced in the process results in a high internal resistance and therefore in a high degree of current limitation; the switching capacity of the switching device 1, in particular the protective switching device, is increased. The above-explained invention can be summarized as follows: In order to specify an arc-quenching apparatus for a switching device 1 which ensures rapid quenching of an arc using simple means with low intrinsic heating, a current conductor track 13 is provided, which has an electrically conductive junction with the further arc guide rail 10 in the form of a conductor loop 10, 13 and is electrically insulated from a switching contact pair 5, 6, the conductor loop 10, 13 being arranged in a connection-free manner with respect to the switching contact pair 5, 6 and in the region of a switching chamber 12 such that a current I, which drives the arc 11 into the arc-quenching chamber 8, is guided via the current conductor track 13 when the arc 11 has commutated from one of the switching contacts 5, 6 to the further arc guide rail 10. WE CLAIM : 1. An arc quenching system for a switching device (1), having an arc guide rail (7) which comprises a fixed contact (5) associated with a moving contact (6), and having an additional arc guide rail (10) at a spacing therefrom, which rails are intended for guiding of an arc (11) into an arcing chamber (8) arranged between the arc guide rails (7, 10) and absorbing the arc (11), and having a current conductor path (13) which comprises an electrically conductive passage to the additional arc guide rail (10) in the manner of a conductor loop (10, 13) and is electrically insulated from the fixed contact (5), wherein the conductor loop (10, 13), without touching the fixed contact (5), is arranged in a region of an interrupting chamber (12) defined by the switching contact pair (5,6) and by the two arc guide rails (7, 10) in such a way that a current (1) driving the arc (11) into the arcing chamber (8) is guided across the current conducting path (13) only when the arc (11) commutates from the moving contact (6) to the additional arc guide rail (10). 2. An arc quenching system as claimed in claim 1, wherein a current conducting path (13) is arranged on the additional arc guide rail (10) on either side of the switching contact pair (5,6). 3. An arc quenching system as claimed in claim 1, wherein a respective conductor loop (10, 13) is arranged on either side of the switching contact pair (5, 6) and the loops are electrically conductive at least at one loop end. 4. An arc quenching system as claimed in claim 1 to 3, wherein the conductor loop (10, 13) is adapted in shape and position to the interrupting chamber (12). 5. An arc quenching system as claimed in any one of the preceding claims, wherein the conductor loop (10, 13) extends into a region of the switching contact pair (5, 6). 6. An arc quenching system as claimed in any one of the preceding claims, wherein the conductor loop (10, 13) extends into a region of the arcing chamber (8). 7. An arc quenching system as claimed in any of the preceding claims, wherein the conductor loop (10, 13) is provided with a first portion (13a) and a second portion (13b) which individually have a position that is substantially parallel to the arc (11) in each case. 8. An arc quenching system as claimed in claim 6, wherein the second portion (13b) of the conductor loop (10, 13) has a length which matches the spacing of the two arc guide rails (7,10) from each other in the region of the arcing chamber (8). 9. An arc quenching system as claimed in any one of the preceding claims, wherein the conductor loop (10,13) is designed in one piece. 10. An arc quenching system as claimed in any one of the preceding claims, wherein the conductor loop (10, 13) is designed as a punched bent part or as a flat strip-bent part or as a wire moulding. 11. An arc quenching system as claimed in any one of the preceding claims, wherein the conductor loop (10,13) extends with one loop end into the region of the arcing chamber (8). 12. An arc quenching system as claimed in claim 11, wherein the conductor loop (10, 13) with its other loop end, is electrically conductively connected to a terminal, in particular also to a thermal tripping device (4). 13. An arc quenching system as claimed in any one of the preceding claims, wherein the arc guide rail (7) is arranged in the manner of a funnel with respect to the additional arc guide rail (20) and in such a way that there is an extension of the arc (11) in the direction of the arcing chamber (8). 14. A switching device (1), comprising an arc quenching system having an arc guide rail (7) which comprises a fixed contact (5) associated with a moving contact (6), and having an additional arc guide rail (10) at a spacing therefrom, which rails are intended for guiding of an arc (11) into an arcing chamber (8) arranged between the arc guide rails (7, 10) and absorbing the arc (11), and having a current conductor path (13) which comprises an electrically conductive passage to the additional arc guide rail (10) in the manner of a conductor loop (10, 13) and is electrically insulated from the fixed contact (5), wherein the conductor loop (10, 13), without touching the fixed contact (5), is arranged in a region of an interrupting chamber (12) defined by the switching contact pair (5,6) and by the two arc guide rails (7,10) in such a way that a current (1) driving the arc (11) into the arcing chamber (8) is guided across the current conducting path (13) only when the arc (11) commutates from the moving contact (6) to the additional arc guide rail (10). |
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01060-kolnp-2006-assignment.pdf
01060-kolnp-2006-correspondence others.pdf
01060-kolnp-2006-description complete.pdf
01060-kolnp-2006-international publication.pdf
1060-KOLNP-2006-ABSTRACT-1.1.pdf
1060-KOLNP-2006-AMANDED CLAIMS.pdf
1060-KOLNP-2006-CANCELLED PAGES.pdf
1060-KOLNP-2006-CORRESPONDENCE.pdf
1060-kolnp-2006-correspondence1.1.pdf
1060-KOLNP-2006-DESCRIPTION (COMPLETE)-1.1.pdf
1060-KOLNP-2006-DRAWINGS-1.1.pdf
1060-KOLNP-2006-ENGLISH TRANSLATION.pdf
1060-kolnp-2006-examination report.pdf
1060-KOLNP-2006-FORM 1-1.1.pdf
1060-KOLNP-2006-FORM 2-1.2.pdf
1060-KOLNP-2006-FORM 3-1.1.pdf
1060-KOLNP-2006-FORM 5-1.1.pdf
1060-kolnp-2006-granted-abstract.pdf
1060-kolnp-2006-granted-claims.pdf
1060-kolnp-2006-granted-description (complete).pdf
1060-kolnp-2006-granted-drawings.pdf
1060-kolnp-2006-granted-form 1.pdf
1060-kolnp-2006-granted-form 2.pdf
1060-kolnp-2006-granted-specification.pdf
1060-KOLNP-2006-OTHERS PATENT DOCUMENTS.pdf
1060-KOLNP-2006-PETITION UNDER RULE 137-1.1.pdf
1060-KOLNP-2006-PETITION UNDER RULE 137.pdf
1060-KOLNP-2006-REPLY TO EXAMINATION REPORT.pdf
1060-kolnp-2006-reply to examination report1.1.pdf
AMANDED PAGES OF SPECIFICATION.pdf
Patent Number | 248586 | ||||||||||||
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Indian Patent Application Number | 1060/KOLNP/2006 | ||||||||||||
PG Journal Number | 30/2011 | ||||||||||||
Publication Date | 29-Jul-2011 | ||||||||||||
Grant Date | 27-Jul-2011 | ||||||||||||
Date of Filing | 25-Apr-2006 | ||||||||||||
Name of Patentee | SIEMENS AKTIENGESELLSCHAFT | ||||||||||||
Applicant Address | WITTELSBACHERPLATZ 2, 80333 MUNCHEN | ||||||||||||
Inventors:
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PCT International Classification Number | H01H 73/18 | ||||||||||||
PCT International Application Number | PCT/EP2004/052831 | ||||||||||||
PCT International Filing date | 2004-11-05 | ||||||||||||
PCT Conventions:
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