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Sept. 24, 1946.
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2,408,352
GAS COOLING ARRANGEMENT FOR CIRCUIT INTERRUPTERS
Filed March 24, 1944
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Inventor‘:
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Charles H. Titus,
by My
His Attof?éy.
Patented Sept. 24, 1946
2,408,352
UNITED STATES PATENT orrlcg
2,408,352
GAS COOLING ARRANGEMENT FOR CIRCUIT
INTERRUPTERS
Charles H. Titus, Philadelphia, Pa., assignor to
General Electric Company, a corporation of
New York
Application March 24, 1944, Serial No. 527,912
6 Claims. (Cl. 200-444)
2
1
,
My invention relates to electric circuit inter
rupters and more particularly to air circuit in
terrupters, and has for its principal object the
provision of an improved circuit interrupter
which is particularly effective in suppressing
flame emission from the arc extinguishing struc
ture of the circuit interrupter by rapidly cooling
the arc gases.
' Favre, Serial No. 555,630, ?led September 25,
1944, and assigned to the same assignee as the
present application.
Mounted in the upper part of casing II of
circuit interrupter ID are a plurality of arc
extinguishing structures or are chutes I5, one
for each pole of the circuit interiupter. Each
of these arc chutes, best shown in Figs. 2 and
3, preferably comprises a structure which may
For a better understanding of my invention,
reference may be had to the accompanying draw 10 be removed as a unit if desired. Furthermore,
these are chutes are formed of an insulating ma
ing in which Fig. 1 is a front view, partly in sec
terial and preferably a bonded asbestos compound
tion, of an electric circuit breaker embodying my
which might comprise a phosphoric asbestos
invention; Fig. 2 is an exploded view in per
compound which could be molded to the desired
spective of the arc extinguishing structure for
one pole of the electric circuit interrupter shown 15 shape. The are chutes might also be made from
asbestos board machined to the proper shape.
in Fig. 1, including the means for suppressing
Each arc chute or are extinguishing structure
?ame emission; Fig. 3 is an enlarged sectional
comprises a pair of outer walls It and I‘! which
view taken on line 3—3 of Fig. 1, and Fig. 4 is
are adapted to be arranged in spaced parallel
a sectional view taken on line 4--4 of Fig. 3.
Although my improved means for suppressing 20 relationship. The arc extinguishing structure
?ame emission from an arc chute may be applied
to any are chute, I have speci?cally illustrated
it as applied to a multiple slot arc chute of the
type disclosed and claimed in the co-pending
is divided into a plurality of narrow slots such as
18, by one or more insulating barriers I9. Since
l as well as in Fig. 3.
of the arc chute 15 are stationary contacts 26
(Fig. 3) which are connected in parallel or
only two multiple contacts for each pole are
illustrated, only a single insulating barrier I9 is
application of Joseph W. Seaman, Serial No. 25 required. Each of the members 16 and I1 is
provided with an extension 20 at one edge
527,913, ?led concurrently herewith and assigned
thereof which cooperates with an extension 2|
tothe same assignee as the present application.
of insulating barrier or wall I9 to determine
Referring now to the drawing, I have illus
the spacing between the members I6, I1 and I9.
trated an electric circuit interrupter generally
indicated at I0, which might be a single-pole 30 The edge of barrier I9 opposite the edge upon
which extension 2| is mounted is adapted to ?t
or multiple-pole circuit interrupter. In Fig. 1 a
within a slot formed by cutaway portions of
three-pole circuit interrupter is indicated com
members I6 and IT. The arc chute is held to
prising an insulating casing II with three
gether as a unitary structure by any suitable
upper terminals I2, and three lower terminals [3
mounted on the casing. Although each pole of . means, which is indicated in the drawing as pins
22', one of which passes through the extensions
the circuit interrupter I0 may include one, two,
2!] and 2| and the other of which passes through
or more contacts in multiple, I have speci?cally
openings 23, 24 and 25 in members I6, H and I9,
illustrated an arrangement in which two contacts
respectively.
are provided in multiple. These contacts are not
Supported from the back wall of casing II in
visible in Fig. 1 but the supporting rods I4 for 40
such a manner as to extend within the slots I8
the movable contacts are clearly visible in Fig.
With the slots of the arc
chute designed for optimum current interrup
tion as will be described hereinafter, it has been
found that two contacts in parallel are satisfac
tory for a IOU-ampere breaker, while three con
tacts in parallel might be desirable for a 200
ampere breaker, and four contacts in parallel
might be desirable for a GOO-ampere breaker, it
being understood that each pole of the circuit
breaker is provided with such multiple contacts.
The operating mechanism and certain other
features of the circuit breaker disclosed in Fig.
1 are not my invention, but are disclosed and
multiple by ?exible copper conductors 21 suitably
connected to terminal I2. In order to prevent
any magnetic forces produced by virtue of the
current flowing through ?exible conductors 21 t0
the bottom of stationary contacts 26 from caus
ing the arc to move downwardly on contacts 26
rather than upwardly, a magnetic shield 28 is
provided which may comprise copper plated
steel, or the like. This magnetic shield is mount
ed between ?exible conductors 2'1 and contacts
26. A rivet 29 holds the shield 28 and ?exible
claimed in the copending application of John A. 55 Conductors 2'! and the terminals I2 in proper
2,408,352
4
alinement as a unitary assembly. This arrange
ment of the stationary contacts is not my inven
tion, but is disclosed in the above mentioned
Favre application.
Cooperating movable contacts 33 are adapted
to be supported on movable conducting support
ing rods id so as to move within the narrow slots
I8 of the arc chutes #5. The movable contacts
I 33 so are arranged that the entire motion there—.
of is within narrow slots l8. Thus the arc ‘is
always drawn at the place where itis to be in
terrupted and no additional means are required
to force the are into the arc chute, as was the
case in prior art constructions. The open posi
tion of movable contacts 3 is indicated by dotted “
lines in Fig. 3.
Upon separation of stationary contacts 25 and
movable contacts 33 an arc will be drawn. Due
to slight mechanical di?erences between the
contacts, this are will always be drawn at one set
of contacts and means must be provided to im
mediately transfer this are to all of the multiple
contacts arranged in parallel since the ability for
tion as far as the U is concerned, while the U
shaped members 34 are in the inverted position.
When nested together or spaced and interleaved
as shown, the respectively inverted and erect
members 34 and 35 form a discontinuous sinu—
soidal member to provide a plurality of sinuous
escape openings for the hot exhaust gases. Pref
erably these U-shaped members nest together so
that the adjacent ends of two inverted U-shaped
members 34 extend within one of the U-shaped
members 35 and‘vice versa. The U-shaped mem
bers at the front and the back of the arc chute
may not be entirely complete, as is clearly shown
.in ‘Fig. 4, and particularly at the back the U
shaped members .34’ and 35' are incomplete in
order to provide room for the stationary contact
assembly. Preferably, the U-shaped members
34 and .35 are constructed of magnetic material
such as copper plated steel, or the like so as to
cause the arc to spread out within the slots to
the best advantage for are interruption purposes.
The copper plating is provided purely as a pro
tective coating to prevent corrosion. By making
one slot to interrupt current is limited. To this
the parts of the mu?ier arrangement discontinu
end I provide the wall or barrier l9 between the 2.5 ous, an adequate creepage path is provided, The
slots l8 with a plurality of openings 32 to provide
hot arc gases contact the rounded bases of the
uniform distribution of the gases and conse
upright U-shaped members 35 and in view of the
quently to produce parallel arcs, one in each slot
smooth surfaces which they engage, little erosion
with the current shared substantially equally be
of the metallic members 35 occurs and the gases
tween the arcs in the respective slots; Although 30 are rapidly cooled. If desired, the inverted U
the openings 32 have been indicated as circular
shaped member 34 may be provided with perfo
openings, it should be understood that this is not
rations 35 either on the sides thereof or as illus
essential and any other means for obtaining dis
trated in the drawing, over the entire surface
tribution of the arc gases between the slots [8,
thereof. With this arrangement additional vent
such as irregular shaped openings, can of course i
ing of the exhaust gases is provided.
be used.
The arc chute was designed by varying the size
The arcs drawn within the arc chute l5 are al
ways extinguished before they engage the me
thereof, the slot spacing and the arrangement of
tallic cooling plates 34 and 35 and only the hot
the holes 32 for optimum current interruption.
arc gases impinge against these plates, which
The greater the current to be carried by each 40 gases are rapidly cooled thereby effectively elim
contact in each slot, the wider the slot and. the
larger the openings between slots. I have found
inating any flame emission from the arc chute
which is due to incandescent gas arcing.
a slot width of less than 1% inch to be very de
sirable, An are chute having a 1%; inch slot Width
struction of the mu?ler comprising metallic cool
It will be noted that with the labyrinthian con
with the openings 32 being T56; inch in diameter
ing plates 34 and 35 the hot gases are forced to
impinge upon both the lower and upper surfaces
holes ?lling the intervening space appeared to
of the plates so that greater cooling is obtained.
yield the best results for the range of short cir
This is possible by virtue of the fact that the hot
cuit currents involved.
gases are generated for only a short period of
The are chutes I5 are open at the top, as best 50 time and because of their relatively high velocity
shown in Fig. 4, in order to provide a passageway
when they impinge against the cooling plates the
33 to atmosphere. In order to cool the arc gases
depth of heat penetration is small. Thus even
and suppress ?ame emission from the arc chute
though the cooling plates are of thin material,
spaced on 1A9, inch centers with alternate rows of
during the circuit interrupting operation, there
both sides thereof can be used as cooling sur
is provided in accordance with my invention a
faces in accordance with my invention.
mu?ler or gas cooling arrangement arranged in
While I have shOWn and described a particu
passageway 33 immediately above barrier l9
lar embodiment of my invention, it will be obvi
which does not extend to the top of the arc chute,
ous to those skilled in the art that various
as is clearly shown in Fig. 4. This mu?ler pref
changes and modi?cations may be made with
erably comprises a series of U-shaped members 60 out departing from my invention in its broader
34 and 35. The U-shaped members 34 and 35
aspects and I, therefore, aim in the appended
have a length dependent upon the spacing be
claims to cover all such changes and modi?ca- .
tween the members I5 and ii. The U-shaped
tions as fall within the true spirit and scope of
members 34 may be supported from member it
my invention.
as by being molded ‘into member E5, or by ‘being
What I claim as new and desire to secure by
cemented into recesses or slots formed in mem
Letters Patent of the United States is:
ber [5. Similarly, the U-shaped members 35
_1. In arc extinguishing means for an electric
may be molded or cemented into member H.
circuit interrupter, an arc extinguishing chamber
Members 34 and 35 might be positioned in slots
having a passageway through which exhaust
in members 15 and I? and held in position by
gases may leave said chamber, and a gas cooling
rivets, such as 22 holding members 16 and H in
arrangement comprising a series of alternately
position. These U-shaped members are nested
erect and inverted U-shaped metallic members
together when the arc chute is completely as
interleaved and spaced in parallel relation across
sembled, as best shown in Fig. 4, with the U
said passageway with the outer side of the'bight
shaped members 35 being in the upright posi 75 of the erect members and the inner side of the
5
2,408,352‘
bight of the inverted members toward the base
of the passageway thereby forming a plurality
of sinuous escape openings for the out?owing hot
exhaust gases of an are formed in said chamber.
2. In arc extinguishing means for an electric
6
escape openings for the out?owing hot exhaust
gases of an arc formed in said chamber, said erect
U-shaped members being supported by one of said
walls and said inverted U-shaped members being
supported by the other of said walls.
circuit interrupter, an arc extinguishing cham
5. In arc extinguishing means for an electric
circuit interrupter, an arc extinguishing cham
ber, a passageway comprising two walls between
ber, a passageway comprising two walls between
which exhaust gases may leave said chamber, and
a gas cooling arrangement comprising a series
which exhaust gases may leave said chamber,
of alternately erect and inverted U-shaped me 10 and a gas cooling arrangement comprising a
series of alternately erect and inverted U-shaped
tallic members interleaved and spaced in parallel
metallic members interleaved and spaced in par
relation across the opening between the walls of
said passageway to provide a plurality of sinuous
allel relation across the opening between the
escape openings for the out?owing hot exhaust
walls of said passageway to provide a plurality of
gases of an arc formed in said chamber, the outer 15 sinuous escape openings for the out?owing hot
side of the bight of the erect U-shaped members
exhaust gases of an are formed in said chamber,
being toward the out?owing hot exhaust gases.
the outer side of the bight of the erect U-shaped
3. In arc extinguishing means for an electric
members being toward the out?owing hot ex
circuit interrupter, an arc extinguishing cham
haust gases and the inverted U-shaped members
being perforated to provide additional venting
ber, a passageway comprising two walls between
means for said exhaust gases.
which exhaust gases may leave said chamber, and
a gas cooling arrangement comprising a series of
6. In arc extinguishing means for an electric
alternately erect and inverted U-shaped metallic
members interleaved and spaced in parallel rela
tion across the opening between the walls of said
the erect members and the inner side of the bight
of the inverted members toward the base of the
passageway thereby forming a plurality of sinu
ous escape openings for the out?owing hot ex
circuit interrupter, an arc extinguishing chamber,
a passageway comprising two walls between
which exhaust gases may leave said chamber, and
a gas cooling arrangement comprising a series
of alternately erect and inverted U-shaped me
tallic members interleaved and spaced in parallel
relation across the opening between the walls of
said passageway to provide a plurality of sinuous
haust gases of an arc formed in said chamber,
escape openings for the out?owing hot exhaust
passagewa r with the outer side of the bight of
certain of said members being perforated to pro
gases of an are formed in said chamber, the outer
vide additional venting for the arc exhaust gases.
side of the bight of the erect U-shaped members
4. In arc extinguishing means for an electric
being toward the out?owing hot exhaust gases
circuit interrupter, an arc extinguishing cham 35 and the inverted U-shaped members being per
ber, a passageway comprising two walls between
iorated to provide additional venting means for
which exhaust gases may leave said chamber, and
a gas cooling arrangement comprising a series
said exhaust gases, and means supporting the
erect U-shaped members from one of said walls
of alternately erect and inverted U-shaped me
and the inverted U-shaped members from the
tallic members interleaved and spaced in parallel 40 other of said walls.
relation across the opening between the walls of
CHARLES H. TI'I‘US.
said passageway to provide a plurality of sinuous
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