ARC PLATE, AND ARC CHUTE ASSEMBLY AND ELECTRICAL SWITCHING
APPARATUS EMPLOYING THE SAME
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to commonly assigned, concurrently filed:
United States Patent Application Serial No. __/ , filed ,
2006, entitled "ARC BAFFLE, AND ARC CHUTE ASSEMBLY AND ELECTRICAL
SWITCHING APPARATUS EMPLOYING THE SAME" (Attorney Docket No. 06-
EDP-245); and
United States Patent Application Serial No. __/ , filed ,
2006 entitled "GASSING INSULATOR, AND ARC CHUTE ASSEMBLY AND
ELECTRICAL SWITCHING APPARATUS EMPLOYING THE SAME" (Attorney
Docket No. 06-EDP-246), which are hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates generally to electrical switching apparatus and, more
particularly, to arc plates for arc chute assemblies of electrical switching apparatus, such
as circuit breakers. The invention also relates to arc chute assemblies for electrical
switching apparatus. The invention further relates to electrical switching apparatus
having one or more arc chute assemblies.
Background Information
Electrical switching apparatus, such as circuit breakers, provide protection
for electrical systems from electrical fault conditions such as, for example, current
overloads, short circuits, and abnormal level voltage conditions.
Circuit breakers, for example, typically include a set of stationary
electrical contacts and a set of movable electrical contacts. The stationary and movable
electrical contacts are in physical and electrical contact with one another when it is
desired that the circuit breaker energize a power circuit. When it is desired to interrupt
the power circuit, the movable contacts and stationary contacts are separated. Upon
initial separation of the movable contacts away from the stationary contacts, an electrical
arc is formed in the space between the contacts. The arc provides a means for smoothly
transitioning from a closed circuit to an open circuit, but produces a number of challenges

to the circuit breaker designer. Among them is the fact that the arc results in the
undesirable flow of electrical current through the circuit breaker to the load.
Additionally, the arc, which extends between the contacts, often results in vaporization or
sublimation of the contact material itself. Therefore, it is desirable to extinguish any such
arcs as soon as possible upon their propagation.
To facilitate this process, circuit breakers typically include arc chute
assemblies which are structured to attract and break-up the arcs. Specifically, the
movable contacts of the circuit breaker are mounted on arms that are contained in a
pivoting assembly which pivots the movable contacts past or through arc chutes as they
move into and out of electrical contact with the stationary contacts. Each arc chute
includes a plurality of spaced apart arc plates mounted in a wrapper. As the movable
contact is moved away from the stationary contact, the movable contact moves past the
ends of the arc plates, with the arc being magnetically drawn toward and between the arc
plates. The arc plates are electrically insulated from one another such that the arc is
broken-up and extinguished by the arc plates. Examples of arc chutes are disclosed in
U.S. Pat. Nos. 7,034,242; 6,703,576; and 6,297,465.
Arc chutes and, in particular, the arc plates of the arc chute are designed to
encourage the arc to enter the arc plates. For example, it has been known to provide the
arc plates of the arc chute with a throat geometry, such as a U-shape or V-shape, which is
structured to attract the arc into the arc plates and thus away from the separable contacts.
However, the arc can undesirably back out of the arc plates and arc chute, toward the
separable contacts. It is, therefore, desirable to not only attract the arc and draw it away
from the separable contacts, but also to retain it within the arc chute so that it may be
effectively split among the arc plates into a series of smaller arcs and dissipated until the
electrical current of the arc is extinguished.
Accordingly, there is room for improvement in arc plates for arc chute
assemblies, and in arc chute assemblies for electrical switching apparatus, such as circuit
breakers.

SUMMARY OF THE INVENTION
These needs and others are met by embodiments of the invention, which
are directed to arc plates with enhanced arc splitting and arc retention for the arc chute
assemblies of electrical switching apparatus, such as circuit breakers.
As one aspect of the invention, an arc plate is provided for an arc chute
assembly of an electrical switching apparatus. The electrical switching apparatus
includes a housing and separable contacts enclosed by the housing. The arc chute
assembly may have first and second opposing sidewalls, and may be disposed proximate
the separable contacts in order to attract an arc generated by the separable contacts
tripping open. The arc plate comprises: a first portion structured to be coupled to one of
the first and second opposing sidewalls of the arc chute assembly; a second portion
structured to be coupled to the other one of the first and second opposing sidewalls of the
arc chute assembly; a first end structured to be disposed proximate the separable contacts
of the electrical switching apparatus; a second end disposed distal from the first end; and
a throat portion disposed between the first portion and the second portion and including
an aperture, the aperture extending from the first end of the arc plate toward the second
end of the arc plate and including an end section disposed at or about the first end of the
arc plate, an intermediate neck section disposed adjacent the end section, and an interior
section disposed adjacent the intermediate neck section and distal from the end section,
wherein the end section of the aperture of the throat portion has a first width and is
structured to attract the arc and direct the arc toward the intermediate neck section of the
aperture of the throat portion, wherein the intermediate neck section of the aperture of the
throat portion has a second width and tapers from the first width of the end section of the
aperture of the throat portion to the second width of the intermediate neck section, the
second width being less than the first width of the end section of the aperture, thereby
further attracting the arc and directing the arc into the interior section of the aperture of
the throat portion, and wherein the interior section of the aperture of the throat portion
includes a taper, the interior section turning with respect to the intermediate neck section
of the aperture of the throat portion, in order to attract and retain the arc therein.
The interior section of the aperture of the throat portion of the arc plate
may further comprise an expanded portion disposed adjacent the intermediate neck

section of the aperture, and having a third width, wherein the third width of the expanded
portion is greater than the second width of the intermediate neck section of the aperture
and is less than the first width of the end section of the aperture. The interior section may
comprise a generally oblong cut-out having a first end comprising the expanded portion,
a second end having a fourth width, and the taper. The taper may generally extend from
the third width of the expanded portion at the first end of the generally oblong cut-out
toward the fourth width of the second end of the generally oblong cut-out, wherein the
fourth width of the second end of the generally oblong cut-out is less than the third width
of the expanded portion of the first end of the generally oblong cut-out. The generally
oblong cut-out may extend generally perpendicularly from the intermediate neck section
of the aperture of the throat portion of the arc plate.
The arc plate may include a centerline extending from the first end of the
arc plate to the second end of the arc plate intermediate the first portion of the arc plate
and the second portion of the arc plate, wherein at least one of the intermediate neck
section of the aperture of the throat portion of the arc plate and the interior section of the
aperture of the throat portion of the arc plate is asymmetric with respect to the centerline.
The aperture of the throat portion may further comprise an edge having a cross-sectional
profile, wherein the cross-sectional profile of at least a portion of the edge is tapered in
order to further attract the arc into the aperture of the throat portion.
As another aspect of the invention, an arc chute assembly is provided for
an electrical switching apparatus including a housing and a pair of separable contacts
enclosed by the housing. The separable contacts are structured to trip open resulting in
an arc being generated. The arc chute assembly comprises: first and second opposing
sidewalls, and a plurality of arc plates disposed between the first and second opposing
sidewalls, each arc plate of the plurality of arc plates comprising: a first portion coupled
to one of the first and second opposing sidewalls of the arc chute assembly, a second
portion coupled to the other one of the first and second opposing sidewalls of the arc
chute assembly, a first end structured to be disposed proximate the separable contacts of
the electrical switching apparatus, a second end disposed distal from the first end, and a
throat portion disposed between the first portion and the second portion and including an
aperture, the aperture extending from the first end of the arc plate toward the second end

of the arc plate and including an end section disposed at or about the first end of the arc
plate, an intermediate neck section disposed adjacent the end section, and an interior
section disposed adjacent the intermediate neck section and distal from the end section,
wherein the end section of the aperture of the throat portion of the arc plate has a first
width and is structured to attract the arc and direct the arc toward the intermediate neck
section of the aperture of the throat portion of the arc plate, wherein the intermediate neck
section of the aperture of the throat portion of the arc plate has a second width and tapers
from the first width of the end section of the aperture of the throat portion to the second
width of the intermediate neck section, the second width being less than the first width of
the end section of the aperture, thereby further attracting the arc and directing the arc into
the interior section of the aperture of the throat portion, and wherein the interior section
of the aperture of the throat portion of the arc plate includes a taper, the interior section
turning with respect to the intermediate neck section of the aperture of the throat portion
of the arc plate, in order to attract and retain the arc within the interior section.
The plurality of arc plates of the arc chute assembly may be substantially
identical and may be disposed within the arc chute assembly spaced one on top of another
with at least one of the intermediate neck section and the interior section of the aperture
of the throat portion of a first one of the arc plates, which is asymmetric, being disposed
backwards with respect to at least one of the intermediate neck section and the interior
section of the aperture of the throat portion of a second one of the arc plates, which is
also asymmetric.
As another aspect of the invention, an electrical switching apparatus
comprises: a housing; separable contacts enclosed by the housing; an operating
mechanism structured to open and close the separable contacts and to trip open the
separable contacts in response to an electrical fault; and at least one arc chute assembly
disposed at or about the separable contacts in order to attract and dissipate an arc which is
generated by the separable contacts tripping open in response to the electrical fault, the at
least one arc chute assembly comprising: first and second opposing sidewalls, and a
plurality of arc plates disposed between the first and second opposing sidewalls, each arc
plate of the plurality of arc plates comprising: a first portion coupled to one of the first
and second opposing sidewalls of the at least one arc chute assembly, a second portion

coupled to the other one of the first and second opposing sidewalls of the at least one arc
chute assembly, a first end disposed proximate the separable contacts of the electrical
switching apparatus, a second end disposed distal from the first end, and a throat portion
disposed between the first portion and the second portion, the throat portion including an
aperture, the aperture extending from the first end of the arc plate toward the second end
of the arc plate, the aperture including an end section disposed at or about the first end of
the arc plate, an intermediate neck section disposed adjacent the end section of the arc
plate, and an interior section disposed adjacent the intermediate neck section of the arc
plate and distal from the end section of the arc plate, wherein the end section of the
aperture of the throat portion of the arc plate has a first width and is structured to attract
the arc and direct the arc toward the intermediate neck section of the aperture of the
throat portion of the arc plate, wherein the intermediate neck section of the aperture of the
throat portion of the arc plate has a second width and tapers from the first width of the
end section of the aperture of the throat portion to the second width of the intermediate
neck section, the second width being less than the first width of the end section of the
aperture, thereby further attracting the arc and directing the arc into the interior section of
the aperture of the throat portion, and wherein the interior section of the aperture of the
throat portion of the arc plate includes a taper, the interior section turning with respect to
the intermediate neck section of the aperture of the throat portion of the arc plate, in order
to attract and retain the arc within the interior section.
BRIEF DESCRIPTION OF THE DRAWINGS
A full understanding of the invention can be gained from the following
description of the preferred embodiments when read in conjunction with the
accompanying drawings in which:
Figure 1 is a cross-sectional view of a portion of a circuit breaker,
including an arc chute assembly and arc plates therefor, in accordance with an
embodiment of the invention;
Figure 2 is an isometric view of the arc chute assembly and arc plates
therefor of Figure 1;
Figure 3 is an isometric view of one of the arc plates of the arc chute
assembly of Figure 1;

Figure 4A is a cross-sectional view taken along line 4A-4A of Figure 3,
showing the edge profile of the throat portion of the arc plate;
Figure 4B is a cross-sectional view showing an edge profile for the throat
portion of an arc plate in accordance with another embodiment of the invention; and
Figure 5 is a top plan view of the arc chute assembly of Figure 2, showing
one arc plate in solid line drawing and a second, adjacent arc plate in hidden line
drawing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
For purposes of illustration, embodiments of the invention will be
described as applied to arc chute assemblies for molded case circuit breakers, although it
will become apparent that they could also be applied to a wide variety of electrical
switching apparatus {e.g., without limitation, circuit switching devices and other circuit
interrupters, such as contactors, motor starters, motor controllers and other load
controllers) having an arc chute.
Directional phrases used herein, such as, for example, left, right, top,
bottom, front, back and derivatives thereof, relate to the orientation of the elements
shown in the drawings and are not limiting upon the claims unless expressly recited
therein.
As employed herein, the statement that two or more parts are "coupled"
together shall mean that the parts are joined together either directly or joined through one
or more intermediate parts.
As employed herein, the term "ionized" means completely or partially
converted into ions and electrons and being at least somewhat electrically conductive
such as, for example, ionized gases generated by arcing between separable electrical
contacts of a circuit breaker when opened.
As employed herein, the term "number" shall mean one or an integer
greater than one (i.e., a plurality).
Figure 1 shows a portion of an electrical switching apparatus, such as a
circuit breaker 2, including a housing 4, separable contacts 6,8 (e.g., stationary contact 6
and movable contact 8), enclosed by the housing 4, and an operating mechanism 10
(shown in simplified form in Figure 1) structured to open and close the separable contacts

6,8. Specifically, the operating mechanism 10 is structured to trip open the separable
contacts 6,8 in response to an electrical fault {e.g., without limitation, an overcurrent
condition, an overload condition, an undervoltage condition, or a relatively high level
short circuit or fault condition). When the separable contacts 6,8 trip open, an arc 12 is
generated as shown in Figure 1. The circuit breaker 2 includes at least one arc chute
assembly 50 disposed at or about the separable contacts 6,8 in order to attract and
dissipate the arc 12.
As best shown in Figures 2 and 5, each arc chute assembly 50 includes
first and second opposing sidewalls 52,54 and a plurality of arc plates 100 disposed
between the first and second opposing sidewalls 52,54. More specifically, each of the
first and second opposing sidewalls 52,54 of the arc chute assembly 50 includes a
plurality of apertures 56,58 (shown only on first opposing sidewall 52 of Figure 2), and
the arc plate 100 includes first and second portions or legs 102,104 each having a number
of protrusions 150,152 (shown only in first opposing sidewall 52 of arc chute assembly
50 of Figure 2). The apertures 56,58 of the first and second opposing sidewalls 52,54
each receive the protrusions 150,152 of a corresponding one of the first and second legs
102,104 of the arc plates 100, as best shown in Figure 5.
Referring to Figures 2,3 and 5, each arc plate 100 includes the first leg
102, which is structured to be coupled to one of the first and second opposing sidewalls
52,54 (Figures 2 and 5) of the arc chute assembly 50 (Figures 2 and 5) and the second leg
104 which is structured to be coupled to the other one of the first and second opposing
sidewalls 52,54 (Figures 2 and 5) of arc chute assembly 50 (Figures 2 and 5), as
previously discussed, a first end 106 structured to be disposed proximate the separable
contacts 6,8 (Figure 1) of the circuit breaker 2 (Figure 1), a second end 108 disposed
distal from the first end 106, and a throat portion 110 disposed between the first leg 102
and the second leg 104. The throat portion 110 includes an aperture 112 which extends
from the first end 106 of the arc plate 100, toward the second end 108 thereof. The
aperture 112 includes an end section 114, which is disposed at or about the first end 106
of the arc plate 100, an intermediate neck section 116, which is disposed adjacent the end
section 114, and an interior section 118, which is disposed adjacent the intermediate neck
section 116 and distal from the end section 114. The end section 114 of the aperture 112

has a first width 120, and is structured to attract the aforementioned arc 12 and direct it
toward the intermediate neck section 116 of the aperture 112. The intermediate neck
section 116 of the aperture 112 has a second width 122 and tapers from the first width
120 of end section 114 to the second width 122 of the intermediate neck section 116. The
second width 122 is preferably less than the first width 120 of the end section 114 of
aperture 112, as shown, in order to further attract the arc 12 (Figure 1) and direct it into
the interior section 118 of aperture 112 of throat portion 110. The interior section 118 of
aperture 112 of the throat portion 110 also includes a taper 124, and turns with respect to
the intermediate neck section 116 of the aperture 112, in order to retain the arc 12 (Figure
1) therein. For example, from the perspective of Figure 3, the interior section 118 of the
example arc plate 100 turns left with respect to intermediate neck section 116 of the
aperture 112 of throat portion 110 of the arc plate 100. However, it will be appreciated
that the interior section 118 could alternatively turn or otherwise be configured in any
suitable manner to attract and retain the arc 12 (Figure 1).
Continuing to refer to Figures 2, 3 and 5, the structure of the throat portion
110 of arc plate 100 will now be described in further detail. Specifically, the interior
section 118 of the aperture 112 of the throat portion 110 preferably comprises an
expanded portion 126, such as the generally oblong cut-out 118, shown. The expanded
portion 126 of the generally oblong cut-out 118 is disposed adjacent to intermediate neck
section 116 of aperture 112, and includes a third width 128 which is greater than the
second width 122 of the intermediate neck section 116 of aperture 112, but less than the
first width 120 of the end section 114 of aperture 112. The generally oblong cut-out 118
has a first end 130 which comprises the expanded portion 126 of the interior section 118,
a second end 132 having a fourth width 134, and a taper 124 generally extending
therebetween. The fourth width 134 of the second end 132 of the generally oblong cut-
out 118 is less than the third width 128 of the expanded portion 126 of the first end 130
of the generally oblong cut-out 118, as shown. The taper 124 helps to
electromagnetically attract the arc 12 (Figure 1) into the interior section 118 of the
aperture 112 for retention therein. Specifically, when the arc is initiated in front of the
arc plates, the magnetic forces are such that the arc 12 (Figure 1) will begin to move
toward section 138. Gas forces also help to drive the arc into the throat portion 110. As

the arc 12 (Figure 1) moves into the throat portion 110, the magnetic forces increases on
the arc 12 (Figure 1) because the throat portion 110 narrows. This forces the arc 12
(Figure 1) into interior section 118 which is expanded to allow the arc 12 (Figure 1) to
expand and reside. If the arc 12 (Figure 1) tries to move back out of the throat portion
110, the metal in section 116 will produce more metal vapor, forcing it back into interior
section 118. Once it is in interior section 118, the arc 12 (Figure 1) prefers to reside in
the expanded portion 126 thereof. In this manner, the example arc plate 100 and, in
particular, the interior section 118 of aperture 112 of the throat portion 110 of arc plate
100, overcomes the disadvantage (e.g., undesirable withdraw of the arc from the arc plate
back towards the separable contacts of the circuit breaker) of the known prior art.
Although the generally oblong cut-out 118 of the example arc plate 100
shown and described herein extends generally perpendicularly from the intermediate neck
section 116 of the aperture 112 of throat portion 110 of the arc plate 100, it will be
appreciated that it could alternatively extend at any suitable angle (not shown) which
would achieve the desired result of retaining the arc 12 (Figure 1), as preciously
discussed.
The arc plate 100 includes a center line 136 extending from the first end
106 to the second end 108 of the arc plate 100 intermediate the first and second legs
102,104 of the arc plate 100, as shown in Figures 2, 3 and 5. At least one of the
intermediate neck section 116 and the interior section 118 of the aperture 112 of throat
portion 110 of the arc plate 100 is asymmetric with respect to the centerline 136. In the
example shown and described herein, both the intermediate neck section 116 and interior
section 118 of the arc plates 100 are asymmetric with respect to the centerline 136.
As best shown in Figure 5, the plurality of arc plates 100 (two arc plates
100 are shown in Figure 5, a top (from the perspective of Figure 5) arc plate 100 shown
in solid line drawing, and underlying substantially identical arc plate 100 partially shown
in hidden line drawing) of the arc chute assembly 50 are substantially identical and are
disposed within the arc chute assembly 50 spaced one on top of another with the
asymmetric portions 116,118 of the alternating arc plates 100 being disposed backwards
with respect to the asymmetric portions 116,118 of adjacent substantially identical arc
plates 100. In other words, as best shown in Figure 5, every other arc plate 100 is flipped

with respect to adjacent arc plates 100. For example, in Figure 5, the top arc plate 100,
shown in solid line drawing, is arranged within the arc chute assembly 50 such that the
protrusions 150,152 of the first portion or leg 102 of the arc plate 100 are received by
apertures 56,58 of the first opposing sidewall 52 of the arc chute assembly 50, and the
protrusions 150,152 of the second portion or leg 104 of the arc plate 100 are received by
apertures 56,58 of the second opposing sidewall 54 of the arc chute assembly 50.
Conversely, the second arc plate 100, partially shown in hidden line drawing in Figure 5,
is coupled to the arc chute assembly 50 such that the protrusions 150,152 of the first
portion or leg 102 of the arc plate 100 are received by apertures 56,58 of the second
opposing sidewall 54 of the arc chute assembly 50, and the protrusions 150,152 of the
second portion or leg 104 of the arc plate 100 are received by apertures 56,58 of the first
opposing sidewall 52 of the arc chute assembly 50. In this manner, the substantially
identical arc plates 100 are disposed opposite with respect to one another such that the
aforementioned asymmetric portions (e.g., intermediate neck section 116 and interior
section 118) are mirrored with respect to one another about centerline 136. It will,
however, be appreciated that the arc plate 100 need not necessarily be identical. It will
also be appreciated that the plurality of arc plates 100 of the arc chute assembly 50 can be
arranged in any other known or suitable configuration other than the alternating back-
and-forth arrangement shown in Figures 2 and 5. For example and without limitation, the
sections 114,116,118 of each arc plate 100 of arc chute assembly 50 could be slightly
different (not shown), and the arc plates 100 could be stacked within the arc chute
assembly 50 all having the same orientation (not shown), in order to direct the arc 12
(Figure 1) within the arc chute assembly 50 in any predetermined desired manner.
As best shown in Figure 3, the aperture 112 of throat portion 110 of arc
plate 100 further includes an edge 138. The edge 138 has a cross-sectional profile 140
which is shown in Figure 4A. Specifically, as shown in Figure 4A, at least a portion 142
of the edge 138 of the aperture 112 (Figure 3) of the throat portion 110 (Figure 3) is
tapered in order to further attract the arc 12 (Figure 1) into the aperture 112 (Figure 3) of
throat portion 110 (Figure 3) of the arc plate 100. It will be appreciated that the portion
142 of the edge 138 of aperture 112 (Figure 3) may comprise the entire edge (not shown)
of the aperture 112 (Figure 3) of the throat portion 110 (Figure 3), or only a smaller

section of the aperture 112 (Figure 3), such as, for example, the intermediate neck section
116 of the aperture 112 in the example of Figure 3, which is tapered.
More specifically, Figures 4A and 4B illustrate two non-limiting
alternative cross-sectional profiles 140,140' for the portion 142,142' of the edge 138,138'
of the aperture 112 (Figure 3) of throat portion 110 (Figure 3), respectively. In the
example of Figure 4A, the portion 142 of the edge 138 of the throat portion 110 (Figure
3) of the arc plate 100 has a first side 144 and a second side 146, both of which include a
taper 148. In this manner, the tapered portion 142 of edge 138 functions to
electromagnetically attract the aforementioned arc 12 (Figure 1) toward the arc plate 100
in the direction generally indicated by arrow 154 in Figure 4A. This further serves to
direct the arc 12 (Figure 1) within the arc plate 100, and retain it therein, as desired.
In the example of Figure 4B, the tapered portion 142' of the edge 138' of
arc plate 100' includes a taper 148' on the first side 144' of portion 142', but not the
second side 146' thereof. It will, however, be appreciated that any known or suitable
tapered edge cross-sectional profile other than the examples shown and described herein
could be alternatively employed without departing from the scope of the invention. It
will further be appreciated that in other embodiments of the invention, no taper (e.g.,
148,148') of any portion of the edge 138 of the arc plate 100 is employed.
It will also be appreciated that although the arc plates 100 have been
shown and described herein with respect to a single arc chute assembly 50 (Figures 1, 2,
and 5) for a circuit breaker 2 (Figure 1), the electrical switching apparatus (e.g., circuit
breaker 2) could employ more than one arc chute assembly 50 each having a plurality of
arc plates 100. For example, and without limitation, the circuit breaker 2 (Figure 1) could
be a multi-pole circuit breaker 2 having a plurality poles (only one pole 14 is expressly
shown in Figure 1) and a corresponding number of arc chute assemblies 50 with arc
plates 100 for the poles 14 of the multi-pole circuit breaker 2.
Accordingly, an arc plate geometry and arc chute assembly configuration
are disclosed which effectively attract, direct, and retain arcs generated, for example, by
the tripping open of the separable contacts 6,8 (Figure 1) of the circuit breaker 2 (Figure
1) in response to an electrical fault. Thus, such arcs 12 (Figure 1) are advantageously
drawn away from the separable contacts 6,8 (Figure 1) and dissipated.

While specific embodiments of the invention have been described in
detail, it will be appreciated by those skilled in the art that various modifications and
alternatives to those details could be developed in light of the overall teachings of the
disclosure. Accordingly, the particular arrangements disclosed are meant to be
illustrative only and not limiting as to the scope of the invention which is to be given the
full breadth of the claims appended and any and all equivalents thereof.

What is claimed is:
1. An arc plate (100,100') for an arc chute assembly (50) of an electrical
switching apparatus (2) including a housing (4) and separable contacts (6,8) enclosed by
said housing (4), said arc chute assembly (50) having first and second opposing sidewalls
(52,54) and being disposed proximate said separable contacts (6,8) in order to attract an
arc (12) generated by said separable contacts (6,8) tripping open, said arc plate (100,100')
comprising:
a first portion (102) structured to be coupled to one of said first and second
opposing sidewalls (52,54) of said arc chute assembly (50);
a second portion (104) structured to be coupled to the other one of said
first and second opposing sidewalls (52,54) of said arc chute assembly (50);
a first end (106) structured to be disposed proximate said separable
contacts (6,8) of said electrical switching apparatus (2);
a second end (108) disposed distal from the first end (106); and
a throat portion (110) disposed between said first portion (102) and said
second portion (104) and including an aperture (112), said aperture (112) extending from
the first end (106) of said arc plate (100,100') toward the second end (108) of said arc
plate (100,100') and including an end section (114) disposed at or about the first end
(106) of said arc plate (100,100'), an intermediate neck section (116) disposed adjacent
said end section (114), and an interior section (118) disposed adjacent said intermediate
neck section (116) and distal from said end section (114),
wherein said end section (114) of said aperture (112) of said throat portion
(110) has a first width (120) and is structured to attract said arc (12) and direct said arc
(12) toward said intermediate neck section (116) of said aperture (112) of said throat
portion (110),
wherein said intermediate neck section (116) of said aperture (112) of said
throat portion (110) has a second width (122) and tapers from the first width (120) of said
end section (114) of said aperture (112) of said throat portion (110) to the second width
(122) of said intermediate neck section (116), the second width (122) being less than the
first width (120) of said end section (114) of said aperture (112), thereby further

attracting said arc (12) and directing said arc (12) into said interior section (118) of said
aperture (112) of said throat portion (110), and
wherein said interior section (118) of said aperture (112) of said throat
portion (110) includes a taper (124), said interior section (118) turning with respect to
said intermediate neck section (116) of said aperture (112) of said throat portion (110), in
order to attract and retain said arc (12) therein.
2. The arc plate (100,100') of claim 1 wherein said interior section (118) of
said aperture (112) of said throat portion (110) of said arc plate (100,100') further
comprises an expanded portion (126) disposed adjacent said intermediate neck section
(116) of said aperture (112) of said throat portion (110), said expanded portion (126)
having a third width (128); and wherein the third width (128) of said expanded portion
(126) of said interior section (118) of said aperture (112) of said throat portion (110) is
greater than the second width (122) of said intermediate neck section (116) of said
aperture (112) of said throat portion (110) and is less than the first width (120) of said
end section (114) of said aperture (112) of said throat portion (110).
3. The arc plate (100,100') of claim 2 wherein said interior section (118) of
said aperture (112) of said throat portion (110) of said arc plate (100,100') comprises a
generally oblong cut-out (118) having a first end (130) comprising said expanded portion
(126), a second end (132) having a fourth width (134), and said taper (124); wherein said
taper (124) generally extends from the third width (128) of said expanded portion (126) at
the first end (130) of said generally oblong cut-out (118) toward the fourth width (134) of
the second end (132) of said generally oblong cut-out (118); and wherein the fourth width
(134) of the second end (132) of said generally oblong cut-out (118) is less than the third
width (128) of said expanded portion (126) of the first end (130) of said generally oblong
cut-out (118).
4. The arc plate (100,100') of claim 3 wherein said generally oblong cut-out
(118) extends generally perpendicularly from said intermediate neck section (116) of said
aperture (112) of said throat portion (110) of said arc plate (100,100').
5. The arc plate (100.100') of claim 1 wherein said arc plate (100,100')
includes a centerline (136) extending from the first end (106) of said arc plate (100,100')
to the second end (108) of said arc plate (100,100') intermediate said first portion (102) of

said arc plate (100,100') and said second portion (104) of said arc plate (100,100'); and
wherein at least one of said intermediate neck section (116) of said aperture (112) of said
throat portion (110) of said arc plate (100,100') and said interior section (118) of said
aperture (112) of said throat portion (110) of said arc plate (100,100') is asymmetric with
respect to said centerline (136).
6. The arc plate (100,100') of claim 1 wherein said aperture (112) of said
throat portion (110) of said arc plate (100,100') further comprises an edge (138,138');
wherein said edge (138,138') has a cross-sectional profile (140,140'); and wherein said
cross-sectional profile (140,140') of at least a portion (142,142') of said edge (138,138')
of said throat portion (110) is tapered in order to further attract said arc (12) into said
aperture (112) of said throat portion (110).
7. The arc plate (100,100') of claim 6 wherein said at least a portion
(142,142') of said edge (138,138') of said throat portion (110) of said arc plate (100,100')
has a first side (144,144') and a second side (146,146'); and wherein said at least a portion
(142,142') of said edge (138,138') includes a taper (148,148') on one of: (a) the first side
(144,144') of said at least a portion (142,142') of said edge (138,138'), (b) the second side
(146,146') of said at least a portion (142,142') of said edge (138,138'), and (c) both the
first side (144,144') and the second side (146,146') of said at least a portion (142,142') of
said edge (138,138').
8. An arc chute assembly (50) for an electrical switching apparatus (2)
including a housing (4) and a pair of separable contacts (6,8) enclosed by said housing
(4), said separable contacts (6,8) being structured to trip open, an arc (12) being
generated in response to said separable contacts (6,8) tripping open, said arc chute
assembly (50) comprising:
first and second opposing sidewalls (52,54), and
a plurality of arc plates (100,100') disposed between said first and second
opposing sidewalls (52,54), each arc plate (100,100') of said plurality of arc plates
(100,100') comprising:
a first portion (102) coupled to one of said first and second
opposing sidewalls (52,54) of said arc chute assembly (50),

a second portion (104) coupled to the other one of said first and
second opposing sidewalls (52,54) of said arc chute assembly (50),
a first end (106) structured to be disposed proximate said separable
contacts (6,8) of said electrical switching apparatus (2),
a second end (108) disposed distal from the first end (106), and
a throat portion (110) disposed between said first portion (102) and
said second portion (104) and including an aperture (112), said aperture (112) extending
from the first end (106) of said arc plate (100,100') toward the second end (108) of said
arc plate (100,100') and including an end section (114) disposed at or about the first end
(106) of said arc plate (100.1001), an intermediate neck section (116) disposed adjacent
said end section (114), and an interior section (118) disposed adjacent said intermediate
neck section (116) and distal from said end section (114),
wherein said end section (114) of said aperture (112) of said throat portion
(110) of said arc plate (100,100') has a first width (120) and is structured to attract said
arc (12) and direct said arc (12) toward said intermediate neck section (116) of said
aperture (112) of said throat portion (110) of said arc plate (100,100'),
wherein said intermediate neck section (116) of said aperture (112) of said
throat portion (110) of said arc plate (100,100') has a second width (122) and tapers from
the first width (120) of said end section (114) of said aperture (112) of said throat portion
(110) to the second width (122) of said intermediate neck section (116), the second width
(122) being less than the first width (120) of said end section (114) of said aperture (112),
thereby further attracting said arc (12) and directing said arc (12) into said interior section
(118) of said aperture (112) of said throat portion (110), and
wherein said interior section (118) of said aperture (112) of said throat
portion (110) of said arc plate (100,100') includes a taper (124), said interior section
(118) turning with respect to said intermediate neck section (116) of said aperture (112)
of said throat portion (110) of said arc plate (100,100'), in order to attract and retain said
arc (12) within said interior section (118).
9. The arc chute assembly (50) of claim 8 wherein said interior section (118)
of said aperture (112) of said throat portion (110) of said arc plate (100,100') further
comprises an expanded portion (126) disposed adjacent said intermediate neck section

(116) of said aperture (112) of said throat portion (110), said expanded portion (126)
having a third width (128); and wherein the third width (128) of said expanded portion
(126) of said interior section (118) of said aperture (112) of said throat portion (110) is
greater than the second width (122) of said intermediate neck section (116) of said
aperture (112) of said throat portion (110) and is less than the first width (120) of said
end section (114) of said aperture (112) of said throat portion (110).
10. The arc chute assembly (50) of claim 9 wherein said interior section (118)
of said aperture (112) of said throat portion (110) of said arc plate (100,100') comprises a
generally oblong cut-out (118) having a first end (130) comprising said expanded portion
(126), a second end (132) having a fourth width (134), and said taper (124); wherein said
taper (124) generally extends from the third width (128) of said expanded portion (126) at
the first end (130) of said generally oblong cut-out (118) toward the fourth width (134) of
the second end (132) of said generally oblong cut-out (118); and wherein the fourth width
(134) of the second end (132) of said generally oblong cut-out (118) is less than the third
width (128) of said expanded portion (126) of the first end (130) of said generally oblong
cut-out (118).
11. The arc chute assembly (50) of claim 8 wherein said arc plate (100,100')
includes a centerline (136) extending from the first end (106) of said arc plate (100,100')
to the second end (108) of said arc plate (100,100') intermediate said first portion (102) of
said arc plate (100,100') and said second portion (104) of said arc plate (100,100'); and
wherein at least one of said intermediate neck section (116) of said aperture (112) of said
throat portion (110) of said arc plate (100,100') and said interior section (118) of said
aperture (112) of said throat portion (110) of said arc plate (100,100') is asymmetric with
respect to said centerline (136).
12. The arc chute assembly (50) of claim 11 wherein said plurality of arc
plates (100,100') of said arc chute assembly (50) are substantially identical and are
disposed within said arc chute assembly (50) spaced one on top of another with said at
least one of said intermediate neck section (116) and said interior section (118) of said
aperture (112) of said throat portion (110) of a first one of said arc plates (100,100'),
which is asymmetric, being disposed backwards with respect to said at least one of said
intermediate neck section (116) and said interior section (118) of said aperture (112) of

said throat portion (110) of a second one of said arc plates (100,100'), which is
asymmetric.
13. The arc chute assembly (50) of claim 8 wherein said aperture (112) of said
throat portion (110) of said arc plate (100,100') further comprises an edge (138,1380;
wherein said edge (138,138') has a cross-sectional profile (140,140'); and wherein said
cross-sectional profile (140,140') of at least a portion (142,142') of said edge (138,138')
of said aperture (112) of said throat portion (110) is tapered in order to further attract said
arc (12) into said aperture (112).
14. The arc chute assembly (50) of claim 8 wherein each of said first and
second opposing sidewalls (52,54) of said arc chute assembly (50) includes a plurality of
apertures (56,58); wherein said first portion (102) and said second portion (104) of said
arc plate (100,100') comprises a first leg (102) and a second leg (104); and wherein said
apertures (56,58) of said first and second opposing sidewalls (52,54) of said arc chute
assembly (50) each receive a portion (150,152) of a corresponding one of said first leg
(102) and said second leg (104) of said arc plate (100,100'), in order to secure said arc
plate (100,100') therebetween.
15. The arc chute assembly (50) of claim 14 wherein said portion (150,152) of
said corresponding one of said first leg (102) and said second leg (104) of said arc plate
(100,100') comprises a number of protrusions (150,152); and wherein said apertures
(56,58) of said first and second opposing sidewalls (52,54) of said arc chute assembly
(50) receive said protrusions (150,152).
16. An electrical switching apparatus (2) comprising:
a housing (4);
separable contacts (6,8) enclosed by said housing (4);
an operating mechanism (10) structured to open and close said separable
contacts and to trip open said separable contacts (6,8) in response to an electrical fault;
and
at least one arc chute assembly (50) disposed at or about said separable
contacts (6,8) in order to attract and dissipate an arc (12) which is generated by said
separable contacts (6,8) tripping open in response to said electrical fault, said at least one
arc chute assembly (50) comprising:

first and second opposing sidewalls (52,54), and
a plurality of arc plates (100,1000 disposed between said first and
second opposing sidewalls (52,54), each arc plate (100,1000 of said plurality of arc plates
(100,100') comprising:
a first portion (102) coupled to one of said first and second
opposing sidewalls (52,54) of said at least one arc chute assembly (50),
a second portion (104) coupled to the other one of said first
and second opposing sidewalls (52,54) of said at least one arc chute assembly (50),
a first end (106) disposed proximate said separable contacts
(6,8) of said electrical switching apparatus (2),
a second end (108) disposed distal from the first end (106),
and
a throat portion (110) disposed between said first portion
(102) and said second portion (104), said throat portion (110) including an aperture (112),
said aperture (112) extending from the first end (106) of said arc plate (100,100') toward
the second end (108) of said arc plate (100,1000, said aperture (112) including an end
section (114) disposed at or about the first end (106) of said arc plate (100,100'), an
intermediate neck section (116) disposed adjacent said end section (114) of said arc plate
(100,100'), and an interior section (118) disposed adjacent said intermediate neck section
(116) of said arc plate (100,100') and distal from said end section (114) of said arc plate
(100,100'),
wherein said end section (114) of said aperture (112) of said throat portion
(110) of said arc plate (100,1000 has a first width (120) and is structured to attract said
arc (12) and direct said arc (12) toward said intermediate neck section (116) of said
aperture (112) of said throat portion (110) of said arc plate (100,100'),
wherein said intermediate neck section (116) of said aperture (112) of said
throat portion (110) of said arc plate (100,1000 has a second width (122) and tapers from
the first width (120) of said end section (114) of said aperture (112) of said throat portion
(110) to the second width (122) of said intermediate neck section (116), the second width
(122) being less than the first width (120) of said end section (114) of said aperture (112),

thereby further attracting said arc (12) and directing said arc (12) into said interior section
(118) of said aperture (112) of said throat portion (110), and
wherein said interior section (118) of said aperture (112) of said throat
portion (110) of said arc plate (100,100') includes a taper (124), said interior section
(118) turning with respect to said intermediate neck section (116) of said aperture (112)
of said throat portion (110) of said arc plate (100,100'), in order to attract and retain said
arc (12) within said interior section (118).
17. The electrical switching apparatus (2) of claim 16 wherein said interior
section (118) of said aperture (112) of said throat portion (110) of said arc plate
(100,100') further comprises an expanded portion (126) disposed adjacent said
intermediate neck section (116) of said aperture (112) of said throat portion (110), said
expanded portion (126) having a third width (128); and wherein the third width (128) of
said expanded portion (126) of said interior section (118) of said aperture (112) of said
throat portion (110) is greater than the second width (122) of said intermediate neck
section (116) of said aperture (112) of said throat portion (110) and is less than the first
width (120) of said end section (114) of said aperture (112) of said throat portion (110) of
said arc plate (100,100').
18 The electrical switching apparatus (2) of claim 16 wherein said aperture
(112) of said throat portion (110) of said arc plate (100,100') further comprises an edge
(138,138'); wherein said edge (138,138') has a cross-sectional profile (140,140'); and
wherein said cross-sectional profile (140,140') of at least a portion (142,142') of said edge
(138,138') of said aperture (112) of said throat portion (110) is tapered in order to further
attract said arc (12) into said aperture (112).
19. The electrical switching apparatus (2) of claim 16 wherein each arc plate
(100,100') of said plurality of arc plates (100,100') has a centerline (136) extending from
the first end (106) of said arc plate (100,100') to the second end (108) of said arc plate
(100,100') intermediate said first portion (102) of said arc plate (100,100') and said
second portion (104) of said arc plate (100,100'); wherein at least a portion (114,116,118)
of said aperture (112) of said throat portion (110) of said arc plate (100,100') is
asymmetric with respect to said centerline (136); wherein each arc plate (100,100') of
said plurality of arc plates (100,100') of said at least one arc chute assembly (50) is

substantially the same; and wherein said arc plates (100,100') which are substantially the
same are disposed within said at least one arc chute assembly (50) spaced one on top of
another with said at least a portion (114,116,118) of said aperture (112) of said throat
portion (110) of a first one of said arc plates (100,100'), which is asymmetric, being
disposed backwards with respect to said at least a portion (114,116,118) of said aperture
(112) of said throat portion (110) of a second one of said arc plates (100,100'), which is
asymmetric.
20. The electrical switching apparatus (2) of claim 16 wherein each of said
first and second opposing sidewalls (52,54) of said at least one arc chute assembly (50)
includes a plurality of apertures (56,58); wherein said first portion (102) and said second
portion (104) of said arc plate (100,100') comprise first and second legs (102,104) of said
arc plate (100,100'); and wherein each of said apertures (56,58) of said first and second
opposing sidewalls (52,54) of said at least one arc chute assembly (50) receives a portion
(150,152) of a corresponding one of said first and second legs (102,104) of said arc plate
(100,100'), in order to secure said arc plate (100,100') therebetween.
21. The electrical switching apparatus (2) of Claim 16 wherein said electrical
switching apparatus is a circuit breaker (2) having a plurality of poles (14); and wherein
said at least one arc chute assembly (50) comprises a plurality of arc chute assemblies
(50) for the poles (14) of said circuit breaker (2).

An arc plate (100,100') for a circuit breaker arc chute assembly (50) includes first and second portions (102,104) coupled to opposing sidewalls (52,54) of the arc chute assembly (50), first and second ends (106,108), and a throat portion (110) between the first
and second portions (102,104) and including an aperture (112). The aperture (112) extends from the first end (106) toward the second end (108) and includes an end section (114), an intermediate neck section (116) adjacent the end section (114), and an interior section
(118) adjacent the intermediate neck section (116) and distal from the end section (114). The end section (114) has a first width (120) and attracts and directs an arc (12) toward the intermediate neck section (116). The intermediate neck section (116) tapers from the
first width (120) of the end section (114) to a second width (122), further attracting the arc (12) and directing it into the interior section (118). The interior section (118) includes a taper (124) and turns with respect to the intermediate neck section (116), in
order to attract and retain the arc (12).