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Патент USA US2406469

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Aug. 27, 1946.
1.. R. LUDWIG ET AL
2,406,469
C IRCUIT INTERRUPTER
Filed Nov. 11, 1942
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‘INVENTORS
L eon A’. Ludwll'g, Mnfhrap M. lead: &
BenjamMRBa/rér
zamamz
6‘ -
ATTOR
‘
Patented Aug. 27, 1946
2,406,469
UNITED STATES PATENT OFFICE
2,406,469
CIRCUIT INTERRUPTER
Leon R. Ludwig and Winthrop M. Leeds, Wil
kinsburg, and Benjamin P. Baker, Turtle Creek,
Pa., assignors to Westinghouse Electric Corpo
ration, East Pittsburgh, Pa., a corporation of
Pennsylvania
Application November 11, 1942, Serial No. 465,244
2 Claims. (Cl. 200-150)
This invention relates to circuit interrupters,
and, more particularly, to are extinguishing
structures therefor. Certain features of the in
vention are described and claimed in applicants’
divisional application, ?led December" 22, 1945,
Serial No. 636,940, entitled, “Circuit interrupt
ers,” and assigned to the assignee of the instant
application.
2
of ?ow of the inwardly flowing streams is changed
to a direction which is longitudinal of the arc,
and‘a plurality of venting passages are provided
for the rapid venting of contaminated ?uid.
Another object is to provide an improved
structure of the type described in the immedi
ately preceding paragraph in which piston means
are disposed between the two arcs to prevent
Other features are described and broadly
contaminated ?uid from the pressure-generating
claimed in a divisional case, ?led December 22, 10 are coming in contact with the interrupting
1945, Serial No. 636,941, entitled “Circuit inter
arc.
rupters,” and assigned to the assignee of the
Another object is to provide an improved cir
instant application.
cuit interrupter wherein fluid adjacent to a
More speci?cally our invention relates to a
pressure-generating arc is forced under pressure
novel structure for effecting the very rapid ex 15 toward the interrupting arc and to dispose pis
tinction of electric arcs drawn in circuit inter
ton means between the two arcs, which piston
rupters. It is particularly applicable to the inter
means can be by-passed near the end of its
ruption of high voltage arcs, such as those drawn
travel.
in a 287 kv. circuit, and will effect their inter
Further objects and advantages will readily
ruption in less than one cycle. Our invention 20 become apparent upon a reading of the follow
is, however, not limited in its application only
ing description taken in conjunction with the
to high voltage circuits. It is also applicable on
drawing, in which:
low voltage circuits, but merely for purposes of
illustration it is described in the speci?cation
in a preferred embodiment as used on a high 25
voltage circuit.
Extensive experimental investigation has clear
Fig. 1 is a side elevational view in cross section
of a circuit interrupter embodying our inven
tion;
Fig. 2 is a side elevational view in cross sec
tion taken on the line II—II of Fig. 1; and
Fig. 3 is a sectional view taken on the line
III-III of Fig. 1.
such as oil, occurs after it impinges upon the
Referring to the drawing and in particular to
arc stream. It is therefore desirable to elimi
Fig. l, the reference numeral I designates gen
nate such contaminated ?uid as quickly as pos
erally an arc extinguishing unit suspended from
sible, and to subject the arc stream to the action
one line terminal of the circuit interrupter in
of fresh ?uid of high dielectric strength. It is
a suitable tank, not shown, and submerged in
one of the objects of our invention to provide 35
a suitable arc extinguishing ?uid, such as oil.
an arc extinguishing structure which makes full
A conducting bridging bar I49 serves to connect
use of this fact.
electrically the arc extinguishing unit I with an
Another object of our invention is to provide
identical unit, not shown, in a manner well
improved piston means associated with the mov
known in the art.
ing contact structure to effect the rapid extinc 40
We have found it desirable to rapidly vent
tion of low current arcs.
ionized products of decomposition resulting from
Another object is to provide an improved arc
an arc extinguishing ?uid impinging upon the
ly demonstrated that a rapid lowering of the
dielectric strength of an arc extinguishing ?uid,
extinguishing structure which directs a plurality
of radially inwardly ?owing streams of ?uid
arc stream.
a pressure-generating arc and an interrupting
arc, the pressure-generating are causing a plu
along the length of the arc stream rather than
After an arc extinguishing ?uid
against the are, changes the direction of flow 45 strikes the arc stream, performing its de-ioniz
ing function by turbulently breaking up and cool
to one which is longitudinal of the arc, and
ing
the ionized arc path, contamination of the
then provides a plurality of radially out?owing
?uid decreases its usefulness for further extin
discharge streams which are substantially per
guishing and. insulating purposes. We have,
pendicular to the arc.
therefore,
found it desirable to subject the arc
Another object is to provide an improved arc
stream to a plurality of radially in?owing streams
extinguishing structure which will, produce both
to use a single stream to de-ionize a consider
able length of arc. At a number of intermedi
Preferably the direction 55 ate points along the arc stream, we provide a
rality of inwardly ?owing streams to converge on
the interrupting arc.
of arc extinguishing ?uid at a number of points
2,406,469
4
3
plurality of vents to allow the contaminated
fluid to be rapidly vented radially outward from
the arc space.
Preferably the inflowing ?uid which strikes the
arc stream should strike the arc radially thereof
from at least opposite sides to maintain the arc
stream in a central position away from adja
cently disposed insulating surfaces. If an arc
contacts an insulating surface it tends not only
to burn away the insulating surface but also
to leave carbon thereon which has conducting
properties. In the construction of our invention
we preferably maintain the are ‘away from ~adja~
cently disposed insulating walls by subjecting
at least opposite sides of the arc stream to a
radially inward flow of ?uid.
In this embodiment of our invention, a plu
rality of insulating plates are pressed togther to
form an insulating arcing structure having en
trance and vent passages more fully described
hereinafter,
Tie rods 62 hold the insulating
plates rigidly in position. A resiliently mounted
relatively stationary contact I42 is provided
which cooperates with an intermediate contact
member I43 to draw a pressure generating arc
I44, ‘as more clearly shown in Fig. 2. The in
termediate contact I43 has secured thereto at its
lower end a metallic spider member I45 which
serves as a lower seat for a battery of compres
sion springs I46.
Cooperating with the inter
mediate contact I43 to draw an interrupting arc
I48 (see Fig. 2) is a lower movable contact I41.
A conducting bridging member I49 operates the
lower movable contact I41.
Suitable operating
mechanism, not shown, actuates the conducting
bridging member I49. A ?exible conductor I56
electrically connects the stationary contact I42
follows the initial movement of the intermediate
contact I43 until the shoulder I58 on the sta
tionary contact I42 strikes the insulating plate
I59. Further downward movement of the lower
movable contact I41 draws substantially simul
taneously both a pressure-generating arc I44 and
an interrupting arc I48, as more clearly shown in
Fig.2.
It would, of course, be possible to have the two
arcs formed sequentially by raising the position
of the insulating plate I59. In this event the
pressure-generatingarc I44 would be formed ?rst,
and the resulting pressure would help to drive
the piston I55 downward.
During the interruption of low currents, the
pressure generated by the pressure-generating
arc I44 will be relatively low and reliance for
the fluid motion is placed on the compression
springs I46. The downward movement of the
piston I155 causes oil to ‘flow as indicated by the
arrows I66 in Fig. 1. The fluid ?ows downwardly
as caused ‘by the piston I55 through two kidney~
shaped vertical flow passages generally desig
nated by the reference numerals 2 provided in
the plurality of contiguously disposed insulating
plates, as shown more clearly in Fig. 3.
After
passing downwardly through the two vertically
disposed ?ow passages 2, the fluid passes radi
ally inwardly toward the interrupting arc 148
through a plurality, in this, instance four, inlet
passages 3 provided by a pair of insulating inlet
plates 4 having a con?guration more clearly
shown in Fig. 3. The ?uid after contacting the
interrupting arc I48 passes upwardly and down
wardly through adjacently disposed ori?ce plates
I152.
5 and out of the arc-extinguishing unit I through
vent passages I61 disposed substantially at right
angles to the direction of the inlet passages 3.
The vent passages I61 are formed by insulating
vent plates 1, which also provide an insulating
It will be apparent that in the closed-circuit po~
sition of the interrupter shown in Fig. 1, the elec
trical circuit therethrough comprises the contact
foot I52, the top metallic plate I5I, ?exible con
the orifice provided by the insulating ori?ce
plates 5. Thus, the ori?ces 8 provided by the
insulating orifice plates 5 and the insulating vent
with a top metallic plate I51 which, in this in
stance, is an integral portion of the contact foot
ori?ce 8 of substantially the same diameter as
ductor I50, relatively stationary contact I42, in 45 plates 1 cause the arc-extinguishing ?uid to ?ow
longitudinally of the interrupting arc I48 inti
termediate contact I43, lower movable contact I41
mately contacting therewith before this arc-‘ex
and conducting bridging member I49, from
tinguishing ?uid is vented out of the arc-extin
whence the circuit passes through another iden
guishing unit I through the oppositely disposed
tical arc extinguishing unit, not shown, to the
venting passages I61 as provided by the vent
other terminal of the interrupter.
plates 1.
Rigidly secured by contact button I53 to the
Certain features of the ?ow passage arrange
intermediate contact I43 is a metallic valve plate
I54. A perforated metallic piston I55 has a lim
ment are described and broadly claimed in U. ‘S.
ited permissible sliding movement with respect
patent application, Serial No. 574,856, ?led Jan
to'the intermediate contact I43 as determined by 55 uary 27, 1945, ‘by Winthrop M. Leeds and Benja
the metallic valve plate I54 and integrally formed
min P. Baker, and assigned to the assignee of the
shoulders I56 formed on the intermediate ‘con
instant invention.
During the interruption of high short~circuit
tact I43.
When the interrupter is in the closed-circuit
currents, the pressure generated by the pressure-.
position, as is shown in Fig, 1, the battery of com 60 generating arc I44 will assist the compression
springs I46 in moving the piston I55 downwardly
pression springs I46 is compressed, metallic pis
ton I55 rests upon the shoulder I56 and the
to cause an increased fluid flow toward the in
terrupting arc I48.
valve I51 is opened. When it is desired to open
the electrical circuit through the interrupter,
It will be observed that when the perforated
suitable operating mechanism, not shown, moves
metallic piston I55 strikes the insulating plate I6 I,
the conducting bridging bar I49 downward. The
as shown by the dotted lines in Fig. 1, ?uid from
intermediate contact I43 being strongly biased
the pressure-generating arc I44 may continue to
downward by the compression springs I46 rapidly
flow past the perforated plate I55 in the annular
follows the initial downward movement of the
space indicated by the reference numeral I62.
lower movable contact I41 to result in the me 70 On the interruption of high currents, this by
tallic valve plate I54 closing the apertures in the
passing action is of advantage for arc interrup
perforated piston I55, the piston I55 remaining
tion which possibly may not have occurred by
practically stationary during this time because of
the time the perforated plate I55 has come to
rest, and further fluid motion caused by the pres
the dashpot action. During the initial movement,
the resiliently mounted stationary contact I42 75 sure generating arc I44 is therefore desirable.
5
2,408,469
It will be observed that in this embodiment of
our invention, we have provided annular pockets
I65 disposed between the inlet passages and the
vent passages. The annular pockets “55 provide
parting from the spirit and scope of the appended
claims.
We claim as our invention:
1. In a circuit interrupter, a relatively station
ary contact, an intermediate contact, a moving
a readily available quantity of oil adjacent the
arc path, and also the annular pockets I65 break
up the insulaitng surfaces adjacent to the are I 43
to minimize the possibility of carbonization of
contact, the intermediate contact being coop
erable with the stationary contact to produce a
these insulating surfaces.
tact being cooperable with the moving contact
We have provided a plurality, in this instance
two, additional annular oil-retaining pockets I65
at the lower end of the structure between the low
er venting passages IE1 and the bottom insu
lating plate I58. It is desirable to maintain an
increased pressure within the arcing region, for
the dielectric strength of an arc extinguishing
?uid depends not only on the degree of ionization
therein but also on the pressure, increased pres
sure causing increased dielectric strength. We
have found that the provision of the oil-retaining
pockets IE6 reduces the gas and ?uid leakage by
making the how more turbulent as the lower mov
able contact MT is Withdrawn out of the are ex
tinguishing structure.
The concept of securing a piston to an inter
mediate contact disposed in an arc extinguishing
unit of the type which produces both a pressure
generating arc and an interrupting arc is de
scribed and broadly claimed in an application
pressure-generating arc, the intermediate con
to draw an interrupting arc, passage means ex
tending between the pressure generating arc and
the interrupting arc, a piston operatively con
nected to the intermediate contact and movable‘
therewith, the piston making a comparatively
tight ?t With the walls of the passage means dur
ing the initial movement thereof, an enlarged
portion in the passage means operative after the
piston has neared the end of its travel to permit
a by-passing of ?uid past the piston, the ?uid
pressure created by the pressure generating arc
assisting in the extinguishment of the interrupt
ing arc.
2. In a circuit interrupter, a relatively sta
tionary contact, an intermediate movable con
tact, a movable contact, the stationary contact
and the intermediate contact cooperating to es
.tablish a pressure-generating arc, the interme
diate contact and the movable contact being co
operable to establish an interrupting arc, a pres
?led September 18, 1942, Serial No. 458,778, by 30 sure chamber adjacent the pressure-generating
Winthrop M. Leeds and Benjamin P. Baker, now
arc, an interrupting passage adjacent the inter
U. S. Patent 2,372,589, issued March 27, 1945, and
rupting arc, passage means extending between the
assigned to the assignee of the instant applica
pressure chamber and the interrupting passage,
tion. Also an application ?led December 26,
piston means operatively attached to and mov
1942, Serial No. 470,161, by John B. MacNeill and
able With the intermediate contact, valve means
assigned to the assignee of the present applica
for the piston means operative upon the initial
tion describes certain improvements in the con
movement of the intermediate contact, the piston
cept of operatively connecting a piston to an in
means extending across the passage means dur
termediate contact in an arc extinguishing struc
ing the initial movement thereof, an enlarged
ture of the type producing both a pressure gen 40 portion in the passage means, the enlarged por~
erating are and an interrupting arc.
tion being so disposed that during the end of the
Although We have illustrated a speci?c em
travel of the piston means a Icy-passing of ?uid
bodiment, it will be clearly understood that the
around the piston means is permissible.
same was merely for purpose of illustration and
LEON R. LUDWIG.
that changes and modi?cations may be made
WINTHROP
M. LEEDS.
therein by those skilled in the art without de
BENJAMIN P. BAKER.
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