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Патент USA US3021419

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Feb. 13, 1962
J. D. COBINE ETAL
3,021,409
CIRCUIT INTERRUPTER
Filed Sept. 24. 1959
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United States ‘Patent
3,021,409
Patented Feb. 13, 1962
2
1
In accord witha speci?c embodiment of the present in
3,021,409
vention, the interrupter is de?ned by electrodes located
James D. Cobine, Rexford, and Newcll C. Cook, Sche
within a substantially enclosed chamber. If desired, the
chamber can be completely enclosed and ?lled with a gas
CIRCUIT INTERRUPTER
, nectady, N.Y., assignors to General Electric Com
pany, a corporation of New York
'
Filed Sept. 24, 1959, Ser. No. 842,011
10 Claims. (Cl. 200-149)
‘
Our invention relates to an improved circuit inter
providing a particularly high normal dielectric strength.
Alternatively, the enclosure may be incomplete and air
may be used as the initial ‘gas. In either event, the sili
con tetra?uoride formed by the arc remains generally in
they chamber after‘ arc extinction. Over a subsequent
rupter.v While not limited thereto, the present invention 10 period of time it recombines with the residual metal ?uo
ride formed when the siliconytetratluoride is generated.
relates particularly ‘to surge voltage protectors for alter
In substantial measure the metal silico-?uoride is thereby
nating current distribution systems and gas type circuit
regenerated and the unit conditioned for further opera- ~
'
tions. Invone embodiment of ‘this form of the structure,
In surge voltage protectors for alternating current sys- ‘
terns, suitably spaced electrodes are provided to form an 15 the electrodes themselves are a repository of metal silico
?uorides so that the reformed metal silico-?uoride is on
are upon the incidence of excessive voltage surges. Such
the electrodes .and is necessarily physically located so as
voltage surges may occur on alternating current power
breakers or interrupters for such systems.
to be subject to the in?uence of the arc, and hence be
system as the consequence of a lightning discharge. Such
come the source of silicon tetra?uoride for further inter
voltage surge may also result from a switching transient.
'
‘
Whatever the source of the voltage surge, it is essential 20 ruptions.
I It is, therefore, an object of the present invention to
that an are be promptly established between the elec
provide an improved circuit interrupter utilizing the usual
trodes, that it be maintained until the voltage surge dis
properties of silicon tetra?uoride.
'
appears, and that it does not restrike when the system
A further object of the present invention is to ' provide
voltage recovers.
v
'
a circuit interrupter using silicon tetra?uoride and in
An alternating current gas (usually air) circuit breaker
or interrupter poses a similar operational problem. Here .
the average circuit opening operation involves separation
of the electrode contact faces while current is ?owing,
and hence, the creation of an arc. The are is frequently
which the current interrupted generates the required sili
con tetra?uoride gas.
'
Another object of the present inventionis to provide ‘
a‘ circuit interrupter using silicon tetra?uoride gas in
maintained for a very considerable portion of the alter 30 which it is unnecessary to surround the arc-electrodes
nating current half-cycle. It is usually not possible-and
indeed it is frequently undesirable—to interrupt the arc
with silicon tetra?uoride gas ina gas-tight chamber.
Still another object of the presentinvention is to pro
vide an improved circuit interrupter in which a metal '
prior to the next occurring current zero. However, when
silico-?uoride is exposed to are action to produce silicon
the instantaneous ‘current does reach a zero (whether the
~
~
,
?rst following electrode separation or some subsequent 35 tetra?uoride gas.
zero), it is important to assure positively that the are is
not restruck when the voltage recovers.
.
Still anothenobject of the present invention is to pro
vide a circuit interrupter especially suitable for use as a‘
In accord with the present invention, the unusual volt?
surge voltage protector where, ceramic insulating surfaces
recovery of dielectric strength following arcing. While
tially formed between separating contacts is propelled
such as insulator. strings are subjected to the thermal in
age recovery properties of silicon. tetra?uoride and the
characteristics of metal silica-?uoride double salts are 40 fluence of thearc.
Yet another object of the present invention is to pro
utilized to provide highly effective surge voltage protec
’vide a circuit interrupter especially suitable for use with
tor and gas circuit breaker or interrupter operation. The
I an air or other gas circuit breaker in which the arc ini
silicon tetra?uoride gas is characterized by a very rapid
‘
the arc exists, the gas provides conduction carriers for 45 against arc-quenching surfaces.
,
The
novel
features
which
we
believe
to
be character~
the electric current. However, when the arc. current
istic of our invention, are set forth with particularity in
' ?ow goes to zero, this gas very abruptly loses its con
‘the appended claims. > Our invention itself, however, both i
ducting capabilities and very quickly forms a medium of
as to its organization and method of operation, together
relatively high dielectric strength. In an actual surge
with
further objects and advantages thereof, will best be
50
voltage protector or circuit breaker constructed in accord
~ understood by reference to the following description taken
with the present invention, the effective length of the are
in connection with theaccompanying drawings, in which:
through the silicon tetra?uoride gas is made‘of sufficient
FIG. 1 is a diagrammatic view of a circuit interrupter
length to de?ne a rate of electric strength recovery ex
of- the expulsion type constructed in accordance with
ceeding the rate of recovery of system voltage. This
assures that the arc is not restruck.
I
,
_
~
,
'
Further in accord with the present invention, the sili
con tetra?uoride gas is formed by the action of the arc
itself upon a non-conducting metal silico-?uoride located
within the zone of thermal in?uence of the arc. The re
‘the present invention;
'
FIG. 2 is an alternative embodiment of the circuit in
terrupter of FIG. 1;
I
I
‘
FIG. 3 is a view of an insulator string with arcing
'rings de?ning a surge voltage protector in accordance '
I
quired silicon tetra?uoride gas is thus formed by the play’ 60 with the present invention; and
I FIG. 4 is a cross-sectional view of an enclosed surge
voltage protector constructed in accordance with the
ing to decompose the metal silico-?uoride into the silicon
‘ present invention.
tetra?uoride. The particular metal silico-?uoride may
of the are upon the metal silica-?uoride, this action serv
Referring now to FIG. ‘1, there ‘is shown in a. some
be any one of a variety of metals. For commercial and
other reasons cuprous silico-?uoride (CuSiF6) is pre 65 what diagrammatic view a circuit interrupter of the gas
ferred.
The silico-?uoride may be located on or be a
type. In the form shown, the interrupter is of the air
part of ‘the arcing surfaces of the electrodes, it may be
break expulsion type.
In this type of interrupter, the
to respond to the arc by the production of silicon tetra
In. the speci?c form of the interrupter shown, the upper
electrode 1 is, made of copperor other ‘suitable material
,arc is drawn into a narrow channel or "tube composed
a separate body within the zone of in?uence of the are,
of, or surfaced with, a material vthat emits gases under
it may be a component of the glaze used on an insulator
over which the arc plays, or it may be otherwise located 70 the in?uence of the‘ arc to aid in extinguishing the arc.
?uoride.
.
>
3,021,409
3
4
and is connected by lug 4 to one conductor 5 of the
connected electric system. The other electrode 2 is in
the form of a ?nger. it is also of a suitable conducting
gas evolved will tend to sweep over the space of the are
before discharging into the atmosphere.
material such as copper.
by support arm 10 through the insulator string and surge
voltage protector 11. The insulator string is made up of
Electrode 2 at its end 2a is
rounded to be received in the mating cup-like recess in
FIG. 3 shows a transmission line conductor 9 carried
of the upper electrode 1 to form an effective current con
a group of connected insulators of the conventional
ducting path.
porcelain type capable of sustaining the weight of the
The electrode 2 is movably supported by suitable means
(not shown).
it is connected to a conductor 6 of the
conductor 9. These are glazed with a material contain
ing a silico-?uoride double salt, such as cuprous silico
connected electrode system by the connector 7, which 10 ?uoride. The arcing rings 13 are provided to form points
of comparatively high electric ?eld gradient between
may be of any suitable form not interfering with the
up and down movement of the electrode 2. In a typical
which the arc is initially struck in the event of an over
voltage on the line conductor 9.
application of an interrupter of this form, the conduc
In the event of an are between the arcing rings 13,
tors 5 and 6, together with the electrodes 1 and 2, may
be in series with ‘an electric system load. In such appli 15 FIG. 3, the are quickly envelops the insulators 12 and
plays upon them. Silicon tetra?uoride evolves from the
cation, the actuating mechanism (which may include a
glaze on the insulators 12 under this action of the arc.
fusible element) pulls the conductor 2 from the contact
making to the contact-breaking position of FIG. 1 in
The arcing space is thus occupied by silicon tetra?uoride
response to excessive load current.
gas and rapidly recovers its dielectric strength when the
surge voltage disappears and the current zero takes place.
FIG. 4 shows still another embodiment of the present
invention as applied to a surge voltage protector. In this
instance, a pair of electrodes 15 are located in spaced
As shown in HS. 1, the sleeve 3 is embedded in and
protrudes from the upper electrode 1. This sleeve has
a longitudinal bore 8 which receives the movable elec
trode 2 with a small annular clearance space. Normally,
this sleeve is made of a material that generates copious
quantities of gas under the in?uence of an are drawn as
the electrode 2 is brought down out of contact with the
electrode 1.
This gas tends to serve as a coolant and
to aid in quenching the arc.
in accordance with the form of the present-invention
relationship in the envelope l4 and have hook portions
16 outside the envelope for attachment to the circuit
terminals to be protected. The envelope 14 is of any
suitable insulating material de?ning a closed space.
Either the electrodes 15 or some other portion of the
unit subjected to the influence of the arc is impregnated
shown in PEG. 1, the sleeve 3 has at least its inside sur 30 or coated with a metal silico-?uoride double salt, such
as cuprous silico-?uoride. In the event or" a voltage surge,
face including a silico-?uoride material. That is, a ma
arcing takes place between electrodes 15, the metal
terial that contains a metallic silico-?uoride. Such ma
silico-?uoride decomposes to form silicon tetra?uoride,
terial may, for example, be incorporated in the mate—
and when the current is ultimately interrupted the silicon
rial from which the entire sleeve 3 is made. Alterna
tively, it may be incorporated in a resin paint or coating 35 tetra?uoride de?nes a space of rapid dielectric strength
recovery to withstand the system recovery voltage applied
that is applied to the inside surface of the sleeve and
between the electrodes.
subsequently hat-dens. In still another construction, the
The closed device of FIG. 4 is essentially completely
sleeve 3 may be of ceramic material and the inner bore
self~regenerating When the arc is interrupted, the silicon
8 coated with a glaze containing silico-?uon'de material.
tetra?uoride in the container envelope begins a process
Many metal silico-?uoride double salts may be used as
of reuniting with whatever metal it contacts. In a struc
the silico—?uoride material. Cuprous silico-?uoride
ture similar to FIG. 4, where essentially all of the exposed
(CuSiF6) is especially useful because it has a favorable
metal is also subjected to the are, essentially all the result
ionizing potential and is commercially available at a
ing metal silieo-?uoride double salt becomes available to
reasonable price. Other suitable materials include cal
cium silico-?uoride (CaSiFs), barium silico-fluoride 45 generate silicon ?uoride upon the next arc interruption.
This regenerative feature is provided to a substantial de
(BaSiFG), sodium silico-?uoride (NaZSiFS), ammonium
silico-lluoride ((NHQZSiFG), and lead silico~fluoride
(PbSiFs). These and other metal silico-?uoride double
salts have the characteristic of decomposing under the
in?uence of the electric arc. The decomposition prod
ucts include silicon tetra?uoride (Silk), a gas under the
conditions of the arc.
Like ‘all the other gases in the are, the silicon tetra
iluoride ionizes and thus provides conduction carriers
for the current. However, this gas has the unusual char
acteristic of providing a very rapid dielectric recovery
voltage upon arc inten'uption. In an exceedingly short
time after arc quench, a space containing a substantial
quantity of silicon tetra?uoride deionizes and defines a
space of substantial dielectric strength.
An apparatus
such as that of FIG. 1 thereby is capable of withstand
ing a very rapidly increasing applied voltage following
are extinction and may be applied to an electric system
with a rapid voltage recovery following a current inter
ruption.
'FIG. 2 shows an alternative form of the structure of
FIG. 1. > In this form the upper electrode 1 is impregnated
with a silico-fluoride material. Since the arc plays upon
gree in structures like those of FIGS. 1 and 2, where a
substantial quantity of the silicon tetratluoride recom
bines with exposed residual electrode materials. It is
most effectively obtained, however, in a completely closed
system such as that of FIG. 4.
While silicon tetra?uoride provides a rapid dielectric
strength recovery, the ultimate dielectric strength of this
gas is of the same order of magnitude as air. In a closed
device such as that of FIG. 4, the ultimate dielectric
strength of this gas is of the same order of magnitude as
air. In a closed device such as that of FIG. 4, the ulti
mate dielectric strength can be somewhat increased by
incorporating a gas of greater dielectric strength. One
such gas is sulfur hexa?uoride (SP6). With a gas of
the type in the envelope 14, the normal breakdown
strength of the protector is determined by the dielectric
strength of this gas and the rate of dielectric strength
recovery following are interruption is determined largely
65 by the action of the silicon tetra?uoride.
‘If desired, the envelope 14 of FIG. 4 may be provided
with a vent to prevent excessive pressure buildup. Some
silicon tetra?uoride will tend to escape through such
vent, but to a considerable degree the self-regenerating
the electrode surface, this material decomposes to gen 70 feature of the structure of FIG. 4 is retained.
erate silicon tetrafluoride in the same ‘fashion above de
in any of the devices made in ‘accordance with the
scribed with reference to sleeve 3. If desired, the mov
present invention it is necessary that the quantity of
able electrode 2 could be so impregnated in lieu of or in
silicon tetra?uoride evolved to be su?icient in relation
addition to electrode 1. It is preferred that at least elec
to the arcing space to provide the necessary dielectric
trade 1 be so impregnated so that the silicon tetrafluoride
strength. That is, when the [arc is interrupted, the silicon
3,021,409
6
4. A surge voltage protector comprising in combina-J
tetra?uoride must be so located that the subsequent system
voltage recovery does not at any time exceed the dielectric
tion: a pair of spaced electrodes with arcing faces de?n
metal silico-?uoride double salt exposed to the arc to
ing an arc-space to be spanned by ‘an arc prior to inter-.
,ruption; and means locatedwithin' the zone of thermal
influence of the arc and including a metal siltco-?uoride
create an ample quantity of silicon tetra?uoride within
, material which when exposed to arcv current ?ow generates
strength available along any complete, path betweenthe
electrodes. This operationis attained byusing su?'icient
silicon tetrai’luoride gas that momentarily occupies the
the arc-space de?ned by the separated arc-electrodes.
arc-space to provide a mediumof rapid dielectric strength '
It will be noted that in each of the devices here shown,
and described a pair of spaced electrode faces are pro
vided between which an arc extends prior to interruption.
The metal silico-?uoride is located on someportion of
the mechanism exposed to the action of the arc. As shown .
by the respective embodiments, the location of the silico
7 recovery upon arc extinction,
I
‘
V
5. A surge voltage protector comprising in combina
tion: a pair of spaced electrodes de?ning an arc-space
between which an arc is'struck upon application of pre
determined surge voitage; and means located within the I‘
to fuses for high voltage interruption, air circuit breakers
‘zone of thermal influence of the arc and including a
metal silico-?uoride material which when exposed to are
‘ ‘current ?ow generates silicon tetra?uoride gas that mo-t
mentarily ‘occupies the arc~space to provide a medium of
rapid dielectric strength recovery upon arc extinction.
’ 6. A surge voltage protector comprising in combina
20 tion: a pair of spaced electrodes de?ning an arc-space
between which an arc is struck upon application of pre
where the arc is magnetically or otherwise driven onto
* determined surge voltage; and insulating means sustain
deionizing means such as arc-chutes and the like (which
ing ‘the electrodes in spaced relation and located within ~
the Zone of thermal in?uence of the arc, said insulating
‘means including surfaces having a metal silico-?uoride
material which when heated by arc current ?ow generates
‘?uoride material maybe varied as desired so long as
it is acted upon by the are.
‘
While we have shown and described particular er'nbodi-i
ments of the present invention it will, of course, be under
stood that various modi?cations and alternative construc
tions may be made without departing from its true spirit
and scope. The invention may, for example, be applied
may include a non~conducting ‘metallic’ silico-?uoride
double salt to generate silicon tetra?uoride) and in other
similar applications. We therefore intend . by the ap
pended claims to cover all such modi?cations and alter
silicon tetra?uoride gas that momentarily occupies the‘ >~
arc-space to provide a medium of rapid dielectric strength
native constructions as fall within their true spirit and
scope.
'
a
'
'
recovery upon arc extinction.
_
Patent of the United States is:
I
.
~ 7. A current interrupter ‘comprising in combination: a
What We claim as new and desire to secure by Letters 30
pair ofspaced electrodeswith.arcing‘faces de?ning an
'
of spaced electrodes within the chamber de?ning an arc-7
arc-space to be spanned by an arc prior to interruption,
at‘ least one ‘of the arcing faces including a metal silico-V
?uoride material which when heated by arc current ?ow
space to be spanned by an arc prior to interruption; and
means located within‘ the zone of thermal in?uence of said
generates silicontetra?uoride gas that momentarily oc
cupies the arc-space to provide a medium of rapid, dielec
are ‘and containing va metal silico~?uoride which upon
tric strength recovery upon arc extinction.
1. A circuit interrupter comprising'in combination: ,
means de?ning a substantially enclosed chamber; ‘a pair ~
that momentarily occupies saidVtarc-space to provide a
medium of rapid dielectric strength recovery upon arc
'
‘ ‘
8. A circuit interrupter comprisingin combination: a
heating by said are ‘generates silicon tetra?uoride gas
?rst means‘ de?ning an electrode face; a second means
40 de?ning an electrode face;~and third means supporting
material within the chamber over a period of time to re
‘said ?rst and ‘second'means in spaced relation to de?ne,
an arc-space to be occupied by an arc prior to interrup
generate metal silico-?uoride and to condition the inter
- tion, at least one of said means having portions exposed
extinction, the gas further recombining with residual
to the action of the arc andincluding a metal silico
rupter for future interruptions.
2. A circuit interrupter comprising in combination: 45
?uoride.
means de?ning a substantially enclosed chamber; and a
pair of spaced electrodes within the chamber de?ning an
arc-space to be spanned by an arc prior to interruption,
at least one of the electrodes de?ning an arcing surface
‘
V
, 9. A circuit interrupter comprising in combination: a
?rstmeans de?ning an electrode faceya second means
de?ning an electrode face; and, third means supporting
said ?rst and second means in spaced relationto de?ne
and containing a metal silico-?uoride which upon heating 50 an arc-space to‘ be occupied by an arc prior to interrup
v'tion, at least one of said meansde?ning portions con
taining cuprous silico-?uoride and exposed to the action
tarily occupies the arc-space to provide a medium’ of
of the are.
rapid dielectric strength recovery upon arc extinction, the
10. _A circuit interrupter comprising in combination: a
gas further recombining with the residual ‘electrode ma
by said arc generates silicon tetra?uoride gas that momen
terial over a period of time to regenerate metal silico 55 ?rst means de?ning an electrode face; a second means - ‘
de?ning an electrode face; and third means supporting ‘
?uoride and to condition theinterrupter for future inter-y
ruptions.
~
said ?rst and second meansin spaced relation to de?ne
an arc-space to be occupied by an arc prior to interrup»
3. A circuit interrupter comprising in combination:
tion, at least one of said means including portions glazed
means de?ning a substantially enclosed chamber; means
including a pair of spaced electrodes with arcing faces 60 with a material including a metal silico-?uoride' andex
de?ning an arc-space to be occupied by an‘arc prior to 1
posed to the action of the arc.
‘
interruption, said means de?ning substantially the only
exposed metal in the chamber and having at least a
References Cited in the tile of this patent
region adjacent one face comprising a metal silico-?uoride
UNITED STATES PATENTS
material which upon heating by said are generates silicon 65
tetra?uoride gas that momentarily occupiesthe arc-space
2,279,040 ‘JGrosse ____________ __;___ Apr. 7, 1942 '
to provide a medium of rapid dielectric strength recovery
2,352,984
Walle _______ __ _______ __ July 4, 1944
upon arc extinction, the gas further recombining with
the residual material of said means over a period of time
to regenerate metal silico-fluoride and to condition the 70
interrupter for future interruption.
2,596,967
Frost __________ _I______ May 20, 1952
2,832,669
Allen __________ __‘_____ Apr. 29, 1958,
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