U.S. patent number 3,594,525 [Application Number 04/817,849] was granted by the patent office on 1971-07-20 for common parallel operating means for series-connected, laterally offset vacuum switches.
This patent grant is currently assigned to General Electric Company. Invention is credited to Richard H. Miller, Bruno C. Rudolph.
United States Patent |
3,594,525 |
Miller , et al. |
July 20, 1971 |
COMMON PARALLEL OPERATING MEANS FOR SERIES-CONNECTED, LATERALLY
OFFSET VACUUM SWITCHES
Abstract
Discloses a high voltage vacuum-type circuit breaker which
comprises a plurality of vacuum interrupters electrically connected
in series. The interrupters are mounted on a skeletonlike structure
that comprises a plurality of aligned tubular insulators
respectively associated with the interrupters in laterally spaced,
generally longitudinally aligned relationship with respect to the
associated interrupter. Adjacent ones of the interrupters in the
series circuit are disposed in laterally offset relation relative
to each other. An operating rod extends through the aligned
insulators, and a plurality of linkages respectively couple the
operating rod to the interrupters.
Inventors: |
Miller; Richard H. (Berwyn,
PA), Rudolph; Bruno C. (Broomall, PA) |
Assignee: |
General Electric Company
(N/A)
|
Family
ID: |
25224016 |
Appl.
No.: |
04/817,849 |
Filed: |
April 21, 1969 |
Current U.S.
Class: |
218/4; 218/140;
200/337 |
Current CPC
Class: |
H01H
33/666 (20130101); H01H 33/008 (20130101); H01H
33/14 (20130101); H01H 2033/146 (20130101); H01H
2033/6623 (20130101) |
Current International
Class: |
H01H
33/666 (20060101); H01H 33/66 (20060101); H01H
33/02 (20060101); H01h 033/66 () |
Field of
Search: |
;200/144.2,145,153H |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
511,515 |
|
Apr 1951 |
|
CA |
|
1,080,198 |
|
Aug 1967 |
|
GB |
|
1,419,176 |
|
Oct 1965 |
|
FR |
|
Primary Examiner: Macon; Robert S.
Assistant Examiner: Vanderhye; Robert A.
Claims
What we claim as new and desire to secure by Letters Patent of the
United States is:
1. A vacuum-type circuit breaker comprising:
a. first, second, and third tubular insulators mounted in
substantially axially aligned relationship,
b. first, second, and third vacuum interrupters respectively
associated with said first, second, and third tubular
insulators,
c. each interrupter comprising an evacuated housing comprising a
tubular insulting casing having a central longitudinal axis, a pair
of separable contacts within said housing, and a conductive rod
supporting a movable one of said contacts and projecting through
one end of said evacuated housing, said rod being longitudinally
movable along a path substantially parallel to said longitudinal
axis,
d. mounting means secured to said insulators, located at one end of
each of said insulators and projecting laterally therefrom for
mounting the vacuum interrupter associated with a given insulator
in laterally spaced, generally longitudinally aligned relationship
with respect to the associated insulator,
e. means for securing said one end of the evacuated housing to its
associated mounting means,
f. means for connecting said interrupters electrically in
series,
g. adjacent ones of all of said vacuum interrupters in said series
circuit being disposed in laterally offset relationship relative to
each other with the longitudinal axes of their tubular casings
disposed substantially parallel to each other,
h. a longitudinally movable operating rod extending through said
substantially aligned tubular insulators substantially parallel to
the longitudinal axes of said insulating casings of said vacuum
interrupters,
i. a linkage associated with each interrupter and coupling the
movable contact rod thereof to said longitudinally movable
operating rod.
2. The vacuum circuit breaker of claim 1 in which said mounting
means at one end of each insulator comprises a housing in which the
linkage coupled to the movable contact rod of the associated
interrupter is housed.
3. A vacuum-type circuit breaker comprising:
a. first, second, and third tubular insulators mounted in
substantially axially aligned relationship,
b. first, second, and third vacuum interrupters respectively
associated with said first, second, and third tubular
insulators,
c. each interrupter comprising an evacuated housing, a pair of
separable contacts within said housing, and a conductive rod
supporting a movable one of said contacts and projecting through
one end of said evacuated housing,
d. mounting means located at one end of each of said insulators and
projecting laterally therefrom for mounting the vacuum interrupter
associated with a given insulator in laterally spaced, generally
longitudinally aligned relationship with respect to the associated
insulator,
e, means for securing said one end of the evacuated housing to its
associated mounting means,
f. means for connecting said interrupters electrically in
series,
g. adjacent ones of said vacuum interrupters in said series circuit
being disposed in laterally offset relationship relative to each
other,
h. a longitudinally movable operating rod extending through said
substantially aligned tubular insulators,
i. a linkage associated with each interrupter and coupling the
movable contact rod thereof to said longitudinally movable
operating rod,
j. the linkage adjacent one end of a given vacuum interrupter
occupying a predetermined space at said one end of said given
interrupter,
k. the interrupter immediately adjacent said given interrupter on
the linkage side of said given interrupter comprising structure
that is disposed in overlapping relationship with said space,
considered in a direction longitudinally of said tubular
insulators.
4. The assembly of claim 1 in which electrically adjacent ones of
said interrupters are disposed in overlapping relationship relative
to each other, considered in a direction longitudinally of said
tubular insulators, thus reducing the overall length of said
assembly.
5. A vacuum circuit breaker as defined in claim 1 and further
comprising:
a. an opening spring coupled to said longitudinally movable
operating rod, said opening spring having its length dimension
extending transversely of said operating rod,
b. and a housing adjacent one of said tubular insulators enclosing
said opening spring and projecting radially outward from the
tubular insulator.
6. A vacuum circuit breaker as defined in claim 1 and further
comprising voltage-dividing capacitors respectively connected in
parallel with said interrupters, the capacitor paralleling a given
interrupter being located in the tubular insulator that is
generally longitudinally aligned with said given interrupter.
7. A vacuum-type circuit breaker as defined in claim 1 and further
comprising means for clamping said tubular insulators and said
mounting means together independently of said vacuum interrupters
so as to form a rigid self-sustaining skeleton on which said vacuum
interrupters are mounted, said vacuum interrupters being
individually removable from said skeleton without affecting its
self-sustaining character and without affecting the mounting of the
other vacuum interrupters.
8. The vacuum circuit breaker of claim 1 in which:
a. said mounting means at one end of each insulator comprises a
housing in which the linkage coupled to the movable contact rod of
the associated interrupter is housed,
b. there is provided clamping means for clamping said tubular
insulators and said linkage housing together independently of said
vacuum interrupters so as to form a rigid, self-sustaining skeleton
on which said vacuum interrupters are mounted,
c. said clamping means comprises insulating tie rods extending
through said aligned tubular insulators, and
d. said vacuum interrupters are individually removable from said
skeleton without affecting its self-sustaining character and
without affecting the mounting of the other vacuum
interrupters.
9. The vacuum-type circuit breaker of claim 1 in which:
a. said tubular insulators have horizontally extending longitudinal
axes,
b. said interrupter casings have horizontally extending
longitudinal axes, and
c. insulating support means is provided at each end of the assembly
of claim 1 for supporting said tubular insulators and said mounting
means independently of said interrupters.
10. The vacuum circuit breaker of claim 1 in which:
a. each interrupter has an end cap supporting the other of its
contacts, and
b. means is provided for supporting said end caps on said tubular
insulators comprising a plurality of mounting brackets respectively
associated with said interrupters,
c. said mounting brackets extending transversely of the
longitudinal axis of their associated interrupters, each bracket
being secured at one point to the associated interrupter end cap
and at a spaced point to structure connected to said tubular
insulators.
Description
This invention relates to a high voltage vacuum-type circuit
breaker, and, more particularly, relates to a circuit breaker of
this type which comprises a plurality of vacuum-interrupting units
electrically connected in series.
In certain prior circuit breakers of this type, the
vacuum-interrupting units have been mounted in aligned relationship
to form an assembly, and an insulating housing of tubular form is
provided about the assembly to provide a weatherproof enclosure.
The individual interrupting units of such an assembly have
typically been operated by one or more movable operating rods
extending longitudinally of the assembly and located within the
weatherproof insulating enclosure. A disadvantage of such an
assembly is that the enclosure diameter must be relatively large in
order to accommodate both the interrupting assembly and the
operating rods, and such large diameter enclosures are quite
expensive. Another disadvantage is that the aligned relationship of
the interrupters necessitates that the assembly and the surrounding
enclosure be unduly long, thus further increasing costs.
An object of our invention is to arrange the vacuum-interrupting
units in such a manner that there is no need for an expensive large
diameter enclosure for enclosing the interrupters and their
operating rods and also in such a manner that the assembly has a
reduced length.
Another object is to provide a high voltage vacuum circuit breaker
that lends itself to being constructed of modular units which can
be used in varying numbers to provide circuit breakers of different
voltage ratings.
Another object is to construct the circuit breaker in such a manner
that individual interrupting units and the operating linkages
therefor can be easily inspected, adjusted, and replaced, if
necessary, without disturbing the remaining interrupting units and
linkages and supporting structure therefor.
In carrying out the invention in one form, we provide first, second
and third tubular insulators mounted in substantially axially
aligned relationship. Associated with said first, second and third
tubular insulators are first, second and third vacuum interrupters,
respectively. Mounting means located at opposite ends of each of
said insulators and projecting laterally therefrom is provided for
mounting the vacuum interrupter associated with a given insulator
in laterally spaced, generally longitudinally aligned relationship
with respect to the associated insulator. The interrupters are
electrically connected in series, and adjacent ones of the
interrupters in said series circuit are disposed in laterally
offset relationship relative to each other. A longitudinally
movable operating rod extends through said substantially aligned
tubular insulators and a linkage is provided in association with
each interrupter for coupling the movable contact rod thereof to
said longitudinal movable operating rod.
For a better understanding of the invention, reference may be had
to the following description taken in conjunction with the
accompanying drawings, wherein:
FIG. 1 is a side elevational view of a portion of a vacuum circuit
breaker embodying one form of our invention.
FIG. 2 is a sectional view along the line 2-2 of FIG. 1.
FIG. 3 is a plan view of the circuit breaker of FIG. 1.
FIG. 4 is a sectional view along the line 4-4 of FIG. 2.
Referring now to FIG. 1, the circuit breaker shown therein
comprises a horizontally extending interrupting assembly 12 and a
pair of horizontally spaced vertical insulating columns 14 and 16
for supporting the interrupter assembly at its opposite ends. The
insulating column 14 carries a metal housing 18 at its upper end to
which the interrupter assembly 12 is suitably secured. This metal
housing 18 and insulating column 14 form the enclosure for a high
voltage current transformer of the type shown in U.S. Pat. No.
3,380,009 to Miller, assigned to the assignee of the present
invention. The details of this current transformer assembly form no
part of the present invention and are therefore not shown
herein.
The vertical insulating column 16 at the right-hand end of the
interrupter assembly 12 is a tubular member that forms a housing
for the reciprocally mounted vertical operating rod 20 of the
circuit breaker. Secured to the top of insulating column 16 is a
metal housing 22 that is suitably secured to the right-hand end of
the interrupting assembly 12. Referring to FIG. 4, within the metal
housing 22 is a bellcrank 24 pivoted at 25 and having one arm
pivotally connected to the vertical operating rod 20. The other arm
of the crank 24 is pivotally connected to a horizontal operating
rod 26, which will soon be described. A suitable operating
mechanism (not shown) is connected to the lower end of the vertical
operating rod 20 to drive it downwardly to close the circuit
breaker, as will soon be explained.
Referring to FIG. 1, the interrupting assembly 12 comprises a
plurality of tubular insulators 30, 31, 32 and 33 disposed with
their longitudinal axes in substantially aligned relationship. At
he right-hand end of each of these tubular insulators 30--33 is a
metal housing 35 of elongated box form. These metal housings 35 are
fixed with respect to the tubular insulators and project radially
outward therefrom. A plurality of tie rods 38 (FIGS. 2 and 3) of
insulating material extend through the aligned tubular insulator
30--33 and are relied upon to clamp the insulators and the metal
housings 35 together so as to form a substantially rigid
self-supporting assembly. This clamping action is produced by nuts
40 (FIG. 3) threaded onto opposite ends of the tie rods 38.
Tightening of the nuts loads the tie rods in tension and the
tubular insulators in compression. Suitable spring washers 42
beneath the nuts 40 at the left-hand end of the tie rods control
the magnitude of the clamping forces.
The interrupting assembly 12 further comprises four vacuum-type
circuit interrupters 50, 51, 52, and 53 electrically connected in
series. Referring to FIG. 4, each interrupter is of a conventional
design and, as such, comprises a highly evacuated tubular envelope
60 and a pair of separable contacts 62 and 63 located within the
envelope. The envelope 60 comprises a tubular casing 66 of a
suitable insulating material, such as glass, and metal end caps 64
and 65 at opposite ends of the casing joined to the casing by
suitable glass-to-metal seals. The contact 62 is a stationary
contact supported on a conductive rod 67 which extends in sealed
relationship through end cap 64; and the other contact 63 is a
movable contact supported on a reciprocally movable conductive
contact rod 68 which extends through the other end cap 65. A
flexible metal bellows 70 joined in sealed relationship at its
opposite ends to the rod 68 and end cap 65 provides a seal about
the rod 68 and permits it to be reciprocated without impairing the
vacuum inside envelope 60. It will be noted that contact rod 68 is
longitudinally movable in a direction parallel to the central
longitudinal axis of surrounding insulating casing 66.
For providing a weatherproof enclosure about each interrupter, the
envelope 60 of each interrupter is encapsulated in a suitable
insulating material which forms a protective shell 72 about the
envelope. The shell 72 is bonded to the exterior of the envelope
and has petticoats on its own exterior to increase the electrical
creepage distances therealong.
Each of these vacuum interrupters 50--53 is mounted adjacent one of
the tubular insulators 30--33 and is disposed in generally
longitudinal alignment with its associated tubular insulator. For
example, referring to FIGS. 1 and 3, the vacuum interrupter 50 is
mounted adjacent tubular insulator 30 and is disposed in generally
longitudinal alignment therewith. A corresponding relationship is
present between insulator 31 and interrupter 51; between insulator
32 and interrupter 52; and between insulator 33 and interrupter 53.
The vacuum interrupter associated with a given tubular insulator is
mounted, in part, on the associated box housing 35 that projects
from the right-hand end of the tubular insulator. This is
illustrated in FIG. 4, where nuts 76 on mounting studs 75 affixed
to the right-hand end cap 65 of interrupter 50 are shown clamping
the end cap to the left-hand end wall 76a of the adjacent box
housing 35.
Referring to FIG. 3, it is to be noted that the interrupters 50,
51, 52, and 53 are so mounted that adjacent ones of the
interrupters have their longitudinal axes laterally offset from
each other and parallel to each other. Considered with respect to a
vertical reference plane 77 passing through the longitudinal axes
of aligned tubular insulators 50--53, (as seen in FIGS. 2 and 3),
adjacent interrupters are located on opposite sides of this
reference plane. To locate the interrupters in this manner, the
longitudinal centerlines 78 of adjacent box houses 35 projecting
from the tubular insulators are disposed on opposite sides of the
reference plane 77, as viewed in FIG. 2.
For supporting the left-hand end of each interrupter 50, 51, and
52, there is a metal bracket 90 secured to the exterior of the box
housing 35 that supports the adjacent interrupter. Studs 92 on the
left-hand end cap of the interrupter are used for attaching the
left-hand end cap to the bracket 90. Bolts 93 (FIG. 2) are used for
detachably securing the metal bracket 90 to the box housing 35
associated with the adjacent interrupter. Each bracket 90 may be
thought of as a cantilever beam extending transversely of the
longitudinal axis of its associated interrupter and secured to the
end cap of the interrupter at its distal end and to the box housing
35 at its proximal end. Interrupter-closing forces are imparted to
the cantilever beam 90 at its distal end.
For electrically connecting the interrupters in series, a plurality
of conductive straps 95 are provided in locations between the
interrupters. Referring to FIG. 2, each of these straps 95 is
connected between the stationary conductive rod 67 of one of the
vacuum interrupters and terminal structure 96 on the box housing 35
supporting an adjacent interrupter. Each conductive strap 95
comprises two parallel sections which are clamped together about
the stationary contact rod 67 of the associated interrupter to
provide a good electrical connection between these parts. Flexible
conductive braid 98 is provided within each of the box housings 35
for connecting the terminal structure 96 thereon to the movable
contact rod of the associated interrupter.
The end interrupters 50 and 53 are electrically connected to the
terminals 102 and 100, respectively of the circuit breaker through
the conductors which can be of any suitable conventional form. For
example, referring to FIG. 4, a conductor 103 of a generally U-form
is used for connecting circuit breaker terminal 102 and the
terminal structure 96 on the adjacent box housing 35 of interrupter
50. The other circuit breaker terminal 100 is at the outer end of
the conductive stud in the current transformer 18, 14. The inner
end of this conductive stud, which is shown at 104, is mechanically
and electrically connected to an adjacent metal housing 105. A
suitable conductor 95a (FIG. 4) is connected between housing 105
and the stationary contact rod 67 of the interrupter 53 at the
left-hand end of the interrupting assembly 12.
For mechanically operating the interrupters 50--53 substantially in
unison, we provide for each interrupter an operating linkage 110
that couples the movable contact rod 68 of the interrupter to the
horizontal operating rod 26. Each of these linkages 110 is located
within the box housing 35 that supports the associated interrupter.
Each linkage 110 comprises a first bellcrank 112 pivotally mounted
on a stationary pivot 113 and having one arm pivotally connected to
the horizontal operating rod 26. The other arm of the bellcrank 112
is connected through a suitable wipe mechanism 115 to an arm of a
second bellcrank 118. The second bellcrank is pivotally mounted on
a stationary pivot 120 and has its opposite arm pivotally connected
to the movable contact rod 68 of the interrupter.
When the horizontal operating rod 26 is driven toward the right
from its position of FIG. 4 it acts through each of the linkages
110 to close the interrupter connected to that particular linkage.
When the horizontal operating rod 26 is returned to its position of
FIG. 4, operating forces are transmitted through linkages 110 to
open the interrupters. It will be apparent from FIGS. 2 and 4 that
the horizontal operating rod 26 extends substantially parallel to
the horizontal contact rods 68 of the interrupters.
The wipe mechanism 115 has been shown in schematic form only since
it can be of any suitable conventional type. An example of a
suitable wipe mechanism is shown in FIG. 5 of U.S. Pat. No.
3,025,375 to Frank, assigned to the assignee of the present
invention.
The operating force for opening the interrupters is derived from an
opening spring 130 disposed in a metal housing 135 of box form
located at the extreme left-hand end of the interrupter assembly
12. This opening spring 130 is a compression spring, the upper end
of which bears against a stationary portion of the housing wall and
the lower end of which bears against a shoulder 132 at the lower
end of a reciprocally movable rod 134. The upper end of rod 134 is
connected to the horizontal operating rod 26 through a bellcrank
136. This bellcrank has one of its arms pivotally connected to the
spring-assembly rod 134 and its other end pivotally connected to
the horizontal operating rod 26. When the horizontal operating rod
26 is moved to the right from its position of FIG. 4 to close the
interrupters, it acts to compress the opening spring 130. Suitable
latch means (not shown) is provided at the lower end of the
vertical operating rod 20 to hold the horizontal operating rod in
its closed position, thereby holding the interrupters in closed
position and holding the opening spring in a compressed condition.
When this latch means is released, the opening spring 130 is free
to discharge, thus driving bellcrank 136 counterclockwise, moving
the horizontal operating rod to the left, thereby opening the
interrupters substantially simultaneously.
For distributing the total voltage approximately equally between
the individual breaks of a multibreak circuit breaker, it is
conventional to provide capacitors of suitable values in parallel
with the breaks. These capacitors can be of any suitable
conventional form, but we prefer to construct each capacitor as an
assembly of stacked ceramic elements, as shown and claimed in U.S.
Pat. No. 3,325,708 to Mankoff et al., assigned to the assignee of
the present invention.
One of the capacitor assemblies is shown in FIG. 4 at 140 in a
location within tubular insulator 30. This assembly 140 is
electrically connected between the two box housings 35 at opposite
ends of the tubular insulator 30. This capacitor assembly by virtue
of these connections parallels the interrupter 50. Additional
capacitor assemblies of the same design can also be mounted in the
tubular insulator 30. Capacitor assemblies of the same design are
provided in each of the other tubular insulators 31, 32, and 33 to
parallel the vacuum interrupters respectively associated with these
tubular insulators. Some of these capacitor assemblies 140 are
shown in FIG. 1. The opposite terminals of each of these capacitor
assemblies are respectively connected to the box housings 35 at the
opposite ends of the associated tubular insulator.
In a tubular insulator 30 of relatively modest size, as seen in
FIG. 2, there is ample room to accommodate centrally located
operating rod 26, the tie rods 38, and the capacitor assemblies
140, inasmuch as all of these components are relatively long and
slender. A tubular insulator of much greater diameter would have
been required had the vacuum interrupter 50 been located therein
since the diameter of the vacuum interrupter is relatively great.
By excluding the vacuum interrupter from this interior space, we
are able to limit the diameter of the tubular insulator to a
reasonable size that is not dictated by the interrupter
diameter.
A factor that contributes to reduced length of the interrupting
assembly 12 is the laterally offset relationship of adjacent vacuum
interrupters. This laterally offset relationship permits the
interrupter units to be mounted with their length dimensions
disposed in overlapping relationship, thus conserving on the
overall length of the interrupting assembly. In this respect, note
in FIG. 3 that the structure projecting from the left-hand end of
the vacuum interrupter 50 overlaps longitudinally of the assembly
with the structure projecting from the right-hand end of the
immediately adjacent interrupter 51. This same overlapping
relationship is present between the other juxtaposed interrupter
units.
If greater reductions in length are desired, the degree of
overlapping can be made more pronounced. Had the interrupter units
been mounted in aligned relationship, it would not have been
feasible to provide any overlap for reducing the overall length of
the interrupting assembly.
Another feature contributing to reduced length of the interrupting
assembly 12 is that the opening spring 130 (FIG. 4) has its long
dimension disposed substantially perpendicular to the length of the
interrupting assembly. Note that this opening spring 130 is
disposed in a box housing 135 that projects radially outward from
the longitudinal axis of the tubular insulators 30--33 in generally
the same manner as the other box housings 35. This perpendicular
disposition of the opening spring renders the length dimension of
the interrupting assembly substantially independent of the length
of the opening spring.
To allow for inspection or adjustment of the linkages 110, each of
the box housings 35 is provided with a large opening that is
normally closed by a removable cover 150. Suitable fasteners (not
shown) are provided to hold each cover in place. When cover 150 is
removed, the associated linkage 110 is freely accessible.
It is a simple matter to remove and replace any of the interrupters
of our circuit breaker assembly. Interrupter removal is
accomplished by first removing the cover 150 adjacent the
interrupter's right-hand end to expose the linkage 110, then
disconnecting linkage 110 and braid 98 from the interrupter, and
then removing the nuts 76 on interrupter mounting studs 75.
Thereafter, the conductor 95 at the left-hand of the interrupter is
disconnected from terminal 96, and the bolts 93 of FIG. 2 are
removed; thus allowing the interrupter together with mounting
bracket 90 and conductor 05 to be completely detached from the rest
of the interrupter assembly. Interrupter replacement is
accomplished by reconnecting these parts in essentially the reverse
order. It is unnecessary to disturb any of the tubular insulators
30--33 or any of the structure mounted therein. It will be apparent
that the tubular insulators 30--33 and the box housings 35, when
clamped together by tie rods 38, form a skeletonlike structure that
is self-sustaining and does not rely upon the vacuum interrupters
for support. Since this skeletonlike structure does not rely upon
the other parts of the interrupter assembly for its support or
structural integrity, these other parts can therefore be freely
removed and replaced without affecting the basic structural
integrity of the skeletonlike structure. Related to the
self-sustaining character of the skeleton structure is the fact
that the supporting columns 14 and 16 at opposite ends of the
assembly support the skeleton independently of the
interrupters.
It will be apparent that our circuit breaker is constructed from
substantially identical modules assembled together in a building
block type of construction. In this regard, each module may be
thought of as comprising one of the tubular insulators, such as 30,
the associated box housing 35, the associated linkage 110, the
associated interrupter 50, and the mounting bracket 90 at the other
end of the interrupter. By adding modules of the same construction
to the circuit breaker assembly of FIG. 1, a circuit breaker of a
higher voltage rating can easily be constructed. Certain additional
changes would also have to be made, such as providing greater
spacing between the supporting columns 14 and 16 to accommodate the
additional modules and increasing the height of columns 14 and 16
to accommodate the higher voltages; but the same basic modules as
shown in FIG. 1 would still be used in the higher voltage
breaker.
Although we prefer to dispose the interrupting assembly 12 so that
it extends horizontally and is supported by insulating columns at
its opposite ends, it is to be understood that our invention in its
broader aspects comprehends an arrangement in which the
interrupting assembly is disposed so that it extends vertically
atop a single insulating structure.
While we have shown and described a particular embodiment of our
invention, it will be obvious to those skilled in the art that
various changes and modifications may be made without departing
from our invention in its broader aspects; and we, therefore,
intend in the appended claims to cover all such changes and
modifications as fall within the true spirit and scope of our
invention.
* * * * *