Title of Invention

ARC QUENCHING DEVICE FOR A LOW-VOLTAGE SWICHING DEVICE

Abstract An arc quenching device for a low voltage switching device which switches in air and having a universally usable, variable attachment for matching the arc quenching chamber to more stringent requirements, characterized in that the attachment is in the form of a chimney-like arcquenching chamber extension in order to increase the volume of the arcquenching chamber, and represents a molding which has a lower contour which is precisely the same as the contour of the arcquenching chamber cover which is normally located on the arcquenching chamber, and whose upper contour is identical to the upper contour of the switch enclosure in order to accommodate the are quenching chamber cover.
Full Text Description
Are quenching device for a low-
voltage switching devices
The invention relates to an arc quenching device for a
low-voltage switching device which switches in air,
having a universally usable, variable attachment for
matching the arc quenching chamber to more stringent
requirements.
Low-voltage circuit breakers which switch in air
require an arc quenching device for operation, in order
to quench arcs that occur without any adverse effect on
the circuit breaker itself or on adjacent system parts
or other assemblies since, if this is not done, there
is a risk of the hot and hence ionized arc gases
causing electrical flashovers, injuring- operators, or
causing other damage.
Two fundamentally different physical forms are known
for the conventional arc quenching devices for low-
voltage circuit breakers. In large circuit breakers,
until now, complete quenching chambers, which are
essentially conventionally produced separately as a
component, that is to say a robust enclosure which is
resistant to arcs, pressure and temperature and has arc
splitters located in it, and a suitable blpwing
apparatus have until now been fitted to the cit.cuit
breaker. One quenching chamber is generally provided
for each pole. This chamber has a complete enclosure
whose strength is matched not only to the mechanical
forces but also to the electrical forces of ther -'arc
which occurs in it and is to be quenched, in particular
with regard to the pressure and the temperature of the
switching gases. The arc splitters are located in this
chamber. The chamber

may in this case be in the form of a pot-like shaft in
which the splitter plates are inserted, or in the form
of a structure composed of half shells in which an
apparatus is required in order firstly to insert the
splitter plates into one half shell, then to fit the
second half shell, and finally to connect the two half
shells.
Quenching chamber inserts are used as a second form, in
which only the function of actual arc quenching can be
achieved in one unit. However, this design is not able
to withstand the pressure which occurs in conjunction
with the arc. These inserts are therefore inserted into
a shaft which is provided in or on the switch
enclosure. Until now, this form has been predominantly
used for small compact circuit breakers, but is also
increasingly being used for relatively large circuit
breakers, where the enclosures surround these areas,
that is to say the switching area and the quenching
area.
In these modern low-voltage circuit breakers, the arc
quenching chambers are integrated in the enclosure of
the switch. The quenching chambers therefore do not
form an object projecting beyond the contour of the
switch. Although, as before, they are autonomous
objects for large circuit breakers, they are, however,
included in the overall design such that they end flush
with the enclosure contours and only the outlet
openings are still visible. However, the parts are
accessible and can be removed in order, for example, to
assess the contacts located underneath them. If
necessary, the entire quenching chamber can also be
replaced.
In certain types of even relatively large low-voltage
circuit breakers, which are referred to by the American
expression

ICCB (insulated case circuit breaker), such a design
has already been chosen in which prefabricated arc
splitter stacks are inserted into the switch enclosure.
However, this results in a secondary problem. The
insertion of the arc splitter stack does not yet in
itself complete the arc quenching device as an entity
since, in the end, the switching gases have to leave
the switch and emerge into free space without being
able to cause any damage.
In conventional circuit breakers, outlet openings are
provided for this purpose in the enclosure, which are a
component of the enclosure, for example a perforated
wall in the enclosure or a wire grating inserted into a
retaining opening in the enclosure. This is necessary
since, after passing through the arc splitter stack,
the switching gasses have not yet been sufficiently
cooled down to allow them to emerge into free space.
The gas is hot and ionized, and this can lead to
flashovers to grounded parts or between busbars. The
hot switching gases may also cause sparks and can
endanger or injure operators. In consequence, further
cooling is essential. Further chamber attachments have
therefore been created. For example, DE-A 35 41 514 and
44 10 108 disclose a completely autonomous structure,
although based on conventional arc quenching chambers,
with enclosure bodies and arc splitters arranged in
them, with damping apparatuses fitted to the quenching
chambers in order to further cool the switching gases,
which are still too hot having passed through the
splitter plates, with the damping apparatus that is
proposed in DE A 44 10 108 being in the form of an
isolating fitted chamber cover, and DE A 35 41 514
indicating a solution in which the attachment contains
a number of perforated inserts which are held by means
of a covering element

through which attachment elements pass. This attachment
is highly complex in terms of design and manufacture
and has only a partial influence on the
characteristics.
A damping insert that is provided also requires a
specific pressure response. The gases must emerge
unimpeded from the arc splitter area and must then be
trapped in a temporary storage area from which, in the
end, they can emerge into free space, after having been
cooled down.
There are situations in which this solution is not
adequate either. EP PS 0437151 Bl discloses a multiple
low-voltage circuit breaker in a dielectric enclosure
which is equipped with a duplicated cooling apparatus
for the quenching gases and is subdivided by dielectric
intermediate walls into a number of internal
compartments, each of which is associated with one of
the poles. In this case, each switching pole has an
associated arc splitter stack for deionization of the
arc that is struck when the contacts are disconnected,
as well as an outlet opening, which is fitted with a
first gas cooling apparatus, for the switching gases.
These outlet openings then open into a further chamber,
which is shared by all the switch poles and has a
second cooling apparatus, after passing through which
the switching gases are dissipated through gas outlet
openings into the surrounding medium. The gases, which
are still very hot and are still highly ionized, meet
one another before the second cooling apparatus, which
can lead to disadvantages. None of the cited solutions
have any damping or blowing devices which themselves
belong to only a single arc quenching chamber, and they
thus represent a comparatively high level of complexity
both with regard to the amount of material and with
regard to the extent of assembly work. Furthermore,
they do not allow the use

of uncomplicated material-saving quenching chamber
designs, since these do not sufficiently damp and cool
down the emerging switching gases. Furthermore, they do
not effectively prevent the still hot, ionized
switching gases from entering areas of the switchgear
assembly in which they can cause damage. For this
reason, known circuit breakers are then subject either
to a restricted voltage range or, as described,
additional parts such as chimneys or attachments with
deionizing media are used. This may be the situation
when an increased short-circuit switching capacity is
required or a higher rated voltage, for example a
higher short-circuit current, since this in general
leads to the quenching chamber having to have a larger
volume because these parameters affect the design of
the quenching chamber, for example the number of arc
splitters, the length of the distance which the arc can
travel on the arc splitters, the nature of the
insulation, damping or deionization at the output of
the quenching chamber, and other features.
The chimneys or attachments which have been mentioned
are, however, always designed for only one specific
situation and cannot be used, extended, varied,
interchanged or replaced universally.
The object of the invention is therefore to provide an
arc quenching device having a variable attachment which
can be used universally in accordance with the normal
present-day constructional ideas, by means of which arc
quenching chambers can be matched to more stringent
requirements without any need to additionally construct
corresponding quenching chambers.
According to the present invention, this object is
achieved by an arc quenching device having an
attachment for low-voltage switching devices, in which
the attachment

is in the form of a chimney-like arc quenching chamber
extension in order to increase the volume of the arc
quenching chamber, and represents a molding which has a
lower contour which is precisely the same as the
contour of the arc quenching chamber cover which is
normally located on the arc quenching chamber, and
whose upper contour is identical to the upper contour
of the enclosure in order to accommodate the arc
quenching chamber cover. The arc quenching chamber is
thus used without the standard cover and, instead of
the cover, a molding is first of all fitted as an
extension to the arc quenching chamber, and to which
the arc quenching chamber cover is now fitted. One or
more further moldings may also be provided in advance,
before the arc quenching chember cover is fitted as a
closure. A molding in this case enlarges the chamber
volume by a specific additional volume.
The configuration of the lower contour of the molding
such that it is identical to the contour of the arc
quenching chamber cover and the embodiment of the upper
contour of the molding such that it is identical to the
upper contour of the enclosure for holding the arc
quenching chamber cover allows any desired number of
moldings to be stacked thus allowing the volume of the
arc quenching chamber to be enlarged by a multiple of
the additional volume in order to comply with the
technical requirements, to be precise simply by forming
a stack of moldings. The switching capacity can thus be
increased in a simple manner.
The material of the molding is expediently identical to
the material of the arc quenching chamber cover.
The special contours of the enclosure, attachment and
arc quenching chamber cover result in labyrinths which
provide a seal for the switching gases

and provide safe phase isolation even in the event of
short circuits.
The attachment or the attachments is or are attached by
means of a screw of appropriate length to the identical
attachment point as the arc quenching chamber cover,
and, as described above, have the insertion/latching
mechanism, which is typical for such covers, for
mechanical coupling between the switch enclosure and
the arc quenching chamber cover. The attachments may
expediently have different heights in the form of sets,
thus allowing the enlargement of the arc quenching
chamber to be matched to the requirements in steps.
To assist understanding, the invention will be
explained in more detail in the following text with
reference to a preferred exemplary embodiment, although
this does not restrict the scope of protection.
Figure 1 shows a low-voltage circuit breaker in which
the control panel and the drive parts are
omitted, in the form of a perspective view,
seen from the front face of the switch.
Figure 2 shows an attachment according to the
invention, in the form of a perspective
illustration, seen from the side of the
attachment screw.
Figure 3 shows the same attachment, in the form of a
perspective view, seen from the opposite
side.
Figure 1 shows a low-voltage circuit breaker 1 with
foot plates 2, from which, in order to improve the
clarity, the control panel and the drive parts have
been omitted, since they are not significant to the
description of the invention. Only the threaded

bushes 3 for the attachment screws which are required
to attach them can be seen, and the through-openings 4
for the switching linkage for the three switching
poles. In order to make the essence of the invention
clear, two quenching chambers are Illustrated in the
normal state, that is to say only those quenching
chamber covers 6; 7 which end flush with the top face 5
of the low-voltage circuit breaker 1 can be seen.
An attachment 8 according to the invention and having a
quenching chamber cover 9 is arranged on the third arc
quenching chamber. The attachment is in the form of an
arc quenching chamber extension in order to enlarge the
volume of the quenching chamber, and represents a
molding 10 whose lower contour 16 precisely matches the
contour of the holder for the arc quenching chamber
cover which is noirmally located on the arc quenching
chamber. The upper contour of the molding 10 is
identical to the upper contour of the enclosure for
holding the arc quenching chamber cover 6; 7; 9. Thus,
instead of the arc quenching chamber cover 6; 7; 9, a
molding 10 is first of all fitted to the arc quenching
chamber as an extension to the arc quenching chamber,
and the arc quenching chamber cover 6; 7; 9 is now
fitted to this. A further molding 10 or a number of
further moldings can now also be provided in advance,
which are then covered by the arc quenching chamber
cover 9. The attachment 10, or the attachments 10, is
or are attached by a screw of appropriate length to the
identical attachment point 11 as the arc quenching
chamber cover.
Figures 2 and 3 show an attachment 8 according to the
invention in the form of a perspective illustration,
seen from different sides. The attachment 8 is in the
form of a molding 10 with a front wall 12, a rear wall
13, a first side wall 14 and a

second side wall 15. It has a lower contour 16 which is
precisely the same as the contour of the arc quenching
chamber cover 6; 7; 9 which is normally located on the
arc quenching chamber, and whose upper contour 17 is
identical to the upper contour of the switch enclosure
in order to hold the arc quenching chamber cover 6; 7;
9 in the normal way. An indentation 18 is provided in
the rear wall 13, through which the attachment screw is
passed, whose length is chosen appropriately to match
the number of attachments 8 that are used.
As described above, the attachment 8 has the
insertion/latching mechanism, which is typical for such
covers, for mechanical coupling between the switch
enclosure and the arc quenching chamber cover 6; 7; 9,
in this case represented by a groove 19 on the top face
20 and by a projection 21, which engages in this groove
when it is being fitted, on the lower face 22 of the
attachment 8.
Once the attachment 8 has been fitted to the switch
enclosure or to a further attachment 8 that is already
present, the arrangement is fixed by means of an
attachment screw, which is passed through the
indentation 18, with the special contours of the
enclosure, attachment and arc quenching chamber cover
producing labyrinths which provide a seal for the
switching gases and ensure safe phase isolation even in
the event of short circuits. Any desired number of
modular attachments 8 can be stacked one on top of the
other in this way.
The invention provides an arc quenching device having a
variable attachment which can be used universally in
accordance with the normal present-day construction
ideas, by means of which arc quenching chambers can be
matched to more stringent requirements

without any need to construct corresponding quenching
chambers in addition.

List of reference symbols
1 Low-voltage circuit breaker
2 Foot plate
3 Threaded bushes
4 Through-opening
5 Top face
6 Quenching chamber cover
7 Quenching chamber cover
8 Attachment part
9 Quenching chamber cover
10 Molding
11 Attachment point
12 Front wall
13 Rear wall
14 First side wall
15 Second side wall
16 Lower contour
17 Upper contour
18 Indentation
19 Groove
20 Top face
21 Projection
22 Lower face

Claims
1. An arc quenching device for a low-voltage
switching device which switches in air and having
a universally usable, variable attachment for
matching the arc quenching chamber to more
stringent requirements,
characterized
in that the attachment (8) is in the form of a
chimney-like arc quenching chamber extension in
order to increase the volume of the arc quenching
chamber, and represents a molding (10) which has a
lower contour (16) which is precisely the same as
the contour of the arc quenching chamber cover (6;
7; 9) which is normally located on the arc
quenching chamber, and whose upper contour (17) is
identical to the upper contour of the switch
enclosure in order to accommodate the arc
quenching chamber cover (6; 7; 9).
2. The arc quenching device as claimed in claim 1,
wherein
in that any desired number of moldings (10) can be
stacked by virtue of the shape of their lower and
upper contours (16; 17).
3. The arc quenching device as claimed in claim 1,
wherein
in that the material of the molding (10) is
identical to the material of the arc quenching
chamber cover (6; 7; 9) .
4. The are quenching device as claimed in claim 1,

wherein
in that the matched contours of the switch
enclosure, attachment (8) and arc quenching
chamber cover (6; 7; 9) form
labyrinths which provide a seal for the switching
gases, and provide safe phase isolation in the
event of short circuits.
5. The arq quenching device as claimed in claim 1,
wherein
in that the upper and lower contours (16; 17) of
the attachment (8) are identical to the
insertion/matching mechanism, which is typical for
such covers, for mechanical coupling between the
switch enclosure and the arc quenching chamber
cover.
6. The are, quenching device as claimed in claim 1,
wherein
in that the attachment (8) or the attachments (8)
is or are attached by means of a screw of
appropriate length to the identical attachment
point (11) as the arc quenching chamber covers (6;
7; 9) .
7. The arc quenching device as claimed in claim 1,
wherein
in that attachments (8) have different heights,
for matching to the requirements for enlarging the
arc quenching chamber.


An arc quenching device for a low voltage switching device which switches
in air and having a universally usable, variable attachment for matching the
arc quenching chamber to more stringent requirements, characterized in that
the attachment is in the form of a chimney-like arcquenching chamber
extension in order to increase the volume of the arcquenching chamber, and
represents a molding which has a lower contour which is precisely the same
as the contour of the arcquenching chamber cover which is normally
located on the arcquenching chamber, and whose upper contour is identical
to the upper contour of the switch enclosure in order to accommodate the are
quenching chamber cover.

Documents:

58-KOLNP-2003-(16-11-2012)-FORM-27.pdf

58-KOLNP-2003-FORM-27.pdf


Patent Number 244869
Indian Patent Application Number 58/KOLNP/2003
PG Journal Number 52/2010
Publication Date 24-Dec-2010
Grant Date 23-Dec-2010
Date of Filing 16-Jan-2003
Name of Patentee SIEMENS AKTIENGESELLSCHAFT
Applicant Address WITTLESBACHERPLATZ 2, 80333 MUNCHEN
Inventors:
# Inventor's Name Inventor's Address
1 SEBEKOW MICHAEL SPINOLASTR. 8, 13125 BERLIN
2 BACH, MICHAEL LIGUSTERWEG 20A, 12437 BERLIN
3 THIEDE, INGO FREGESTR. 76, 12159 BERLIN
4 SCHMIDT, DETLEV RICHARDSTR, 61, 12055 BERLIN
5 SEIDLER-STAHL, GUNTER STERNSTR. 11, 13350 BERLIN
6 TURKMEN, SEZAI SCHUCKERTRDAMM 334, 13629 BERLIN
PCT International Classification Number H01H 9/34
PCT International Application Number PCT/DE2001/02533
PCT International Filing date 2001-07-05
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 100 36 370.9 2000-07-18 Germany