Title of Invention

AN ARC QUENCHING SYSTEM FOR A SWITCHING DEVICE

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).

Documents:

01060-kolnp-2006-abstract.pdf

01060-kolnp-2006-assignment.pdf

01060-kolnp-2006-claims.pdf

01060-kolnp-2006-correspondence others.pdf

01060-kolnp-2006-description complete.pdf

01060-kolnp-2006-drawings.pdf

01060-kolnp-2006-form 1.pdf

01060-kolnp-2006-form 2.pdf

01060-kolnp-2006-form 3.pdf

01060-kolnp-2006-form 5.pdf

01060-kolnp-2006-international publication.pdf

01060-kolnp-2006-pct form.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 18.pdf

1060-KOLNP-2006-FORM 2-1.2.pdf

1060-KOLNP-2006-FORM 3-1.1.pdf

1060-kolnp-2006-form 3.pdf

1060-KOLNP-2006-FORM 5-1.1.pdf

1060-kolnp-2006-form 5.pdf

1060-KOLNP-2006-FORM-27.pdf

1060-kolnp-2006-gpa.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-others.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

abstract-01060-kolnp-2006.jpg

AMANDED PAGES OF SPECIFICATION.pdf


Patent Number 248586
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:
# Inventor's Name Inventor's Address
1 GUNTHER ECKERT AM DORFWEIHER 8 A, 93142 MAXHÜTTE-HAIDHOF
2 WOLFGANG LEITL SCHLEHENWEG 19, 93173 WENZENBACH
3 PAUL HERMA HÄNDELSTR. 29, 93133 BURGLENGENFELD
PCT International Classification Number H01H 73/18
PCT International Application Number PCT/EP2004/052831
PCT International Filing date 2004-11-05
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10352934.9 2003-11-11 Germany