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Dec. 3, 1946.
2,411,893
G_ w_ PETERS
METHOD OF CONTROLLING AN ARC
Filed my 8. 1945
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a. w. PETERS
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METHOD OF CONTROLLING AN ARC
Filed July 8, 1943
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INVENTOR.
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‘Patented Dec. 3, 1946
iU-NlT-ED STATES; PATENT
DFFICE
2,411,893
IVLETHOD OF CONTROLLING ARCS
. Gerhard W. Peters; Akron, Ohio~
Application July 8, 1943, Serial No. 493,848
1 Claim. _ (01. 2004-147)
,
1
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2
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This invention relates to methods'and means
for extinguishing the electric arcs drawn between
sides toward the central or intermediate portions
of the contacts. Growth or propagation of ?ame
electrodes or contacts in an electric circuit; and '
is thereby prevented. As the contacts, between
particularly to such methods and means that
which the arc is drawn, move apart, the arc
'utilize the reaction of the are on a'magnetic ?eld. 6 appears to be drawn into the general form of a
The invention is applicable to electric, circuit
cone, and at its apex, the cone becomes more
breakers generally. One of its most important
and more attenuated until continuity of the arc
uses, however, is in connection with the class of '
ceases and it “goes out."v I am not certain as
electric contactors whose contacts are frequently
'tothe true theoretical explanation of this ac
closed and opened to make and break, and there .10 tion, but I believe that the are extlnguishes itself
by control,‘ the current in an electric circuit,» and
in this manner because its resistance becomes
hereinafter it will be described in connection
so high ‘due to the decreasing cross~section at its
with such make and break contactors, and par
apparent cone apex that the potential across the
ticularly the contacts applicable thereto, as illus
separated contacts between which it is drawn
trative of one of the uses of the invention.
15 cannot maintain the current flow in it.
The employment of a magnetic ?eld to rupture
All of the visible phenomena oi.’‘ the rupturing
the are drawn between the contacts of a con
_ tactor, is generally old and well known. Accord
are are thus con?ned to the‘ space between the
contacts, and to the intermediate portions of
the contact surfaces; the evolution of ?ame is
of the magnetic ?eld are made to lie in such po 20 prevented; the explosive sound usually accom
sition and direction relative to the arc, that the
panying the rupturing of ?aming arcs is absent;
current in the arc reacts‘ thereon and moves
the usual provisions for dealing with the destruc-'
ing to the well known principle, the linesof force
across or out of the‘?eld (in much the same way
tive and dangerous ?ame are unnecessary; the
as the_current carrying conductor of an electric
burning of the contacts is greatly reduced and
motor moves in the motor ?eld) ; and the move 25 their life accordingly prolonged; and an increase
‘ment of the arc and its reaction on the ?eld
in the current that can be carried and interrupt
causes it to lengthen and ?nally rupture. The
arc is usually formedin the air at atmospheric
' _ pressure and ionizes the air and produces ?ame.
ed by contacts of a given size is e?ected.
It is accordingly among the objects of the in- ‘
The ?ame is one of the arc phenomena and in 30
many instances propagates itself to great length
and cross sectional area compared with the arc
proper; and the ?ame must usually be housed
or con?ned by walls or barriers to prevent injury
vention:
_
To provide generally an improved means and
method, utilizing a magnetic ?eld for extinguish
ing the are drawn between separable contacts or
electrodes;
,
To provide a means and method for extinguish
toadjacent parts thereby, and to prevent the 85 ing arcs, drawn between separating contacts,
?ame from bridging metal parts and making a
which progressively transversely constricts the
- short circuit in the contactor. The ?ame there
arc as the contacts separate;
fore must be dealt with concurrently with the
To provide ,an improved method and means for
extinguishing arcs drawn between separating
It has been proposed to destroy or rupture the~ 40 contactswhich causes the arc to 'de?ne in space
are proper.
'
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the form generally of a cone as the contacts sep
arc and ?ame magnetically by'?rst breaking it
arate;
'
up into a plurality of smaller arcs; or by'forc
~ To provide a method and means for extinguish
ing it magnetically into the spaces between a
plurality of closely spaced ?ns or plates to there 45 ing a plurality of arcs, drawn between a plural
ity of sets of separating contacts, in series re
by break up and deionize the ?ame‘. It has also
lation in an electric circuit, which causes at least
been proposed to cause the arc and ?ame to rup
one of the arcs'to be progressively constricted as
ture more easily by causing the arc to be moved
magnetically along a linear conducting path of -
'the contacts separate and to thereby cause the
of the circuit at both contacts to be ef
increasing length and corresponding increasing 50 breaking
fected in an improved manner;
'
ohmic resistance.
'
The present invention makes a'radicald‘epar- "
ture from these and all other prior principles by
utilizing a. magnetic ?eld in suchv manner that
To provide a means and method for extinguish
ing arcs drawn between separating contacts,
which causes the arc, and any ?ame which may
be initiated, to be drawn inwardly‘toward the in
when an arc is drawn in the ?eld between a pair 55 termediate portions of the contact surfaces, and
of contacts. the mutual reaction of the arc and _
to be extinguished thereat';
the ?eld. causes the arc and any ?ame which
may be initiated, to be drawn inwardly fromgall
To provide an improved method and means
' for breaking an are drawn between contacts
9,411,393;
4
which causes the arc to be severed at its ‘lunc
ture with one .of the contacts while the contacts
are separating;
To provide a method and means for breaking an
V arc drawn between contacts which is~applicabie
with improvement advantages to single-breaker
todouble-break contactors, and to alternating or
provided to stop theelectr'o'de a ‘in its downward 4
movement to determine a maximum distance be
tween the contact tips ‘2-4. for test purposes. '
An electric circuit is shown as leading from a
current supply main 8, through an ammeter 8
and a load resistance I 0, to the electrode I, and
' from the electrodev 3 by way of a ?exible connector
II to the other supply main II. A winding I3
to direct current circuits:
Other objects‘ will be apparent to those skilled
in the art to which my invention appertains.
My invention is fully disclosed in the following
description taken in connection with the accom
surrounds the electrode I and is connected at one
end to the supply main 8, and at the other end is
connected, through a rheostat comprising. a re
sistor I4 and a-movable contact I5, to the main I2.
For any position of. the contact I 5, the winding I8
_ Figure 1 is a diagrammatic view illustrating an
will be energized and will produce a magnetic ?eld
apparatus by which certain principles of the in-~ 15 in the space between the arcing tips 2 and 4. The
vention‘ hereinafter set forth may be demon
magnetic ?ux thus produced is illustrated con
ventionally by lines I6 and is seen to flow longitu
Figures 2m 6 inclusive are fragmentary views
dinally through the magnetic electrode I, and to
similar to a part of Figure 1 and showing electric ' emerge at its end through the tip Zinto the at- contacts of Figure 1. in fully open position and 20' mosphere as a magnetic?eld between the tips 2
illustrating the changes which take place in an
and ‘a As will be understood this field is gen
arc drawn between the contacts concurrently with
erally symmetrical with respect to the axis of the
increasing energization of an electro-magnetic
winding I3 although exact symmetry is not essen
winding of Figure ,1;
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tial. The lines within the magnetic electrode I
Figure 7 is a fragmentary view similar to a part 25 ?ow generally parallel to the axis of'the wind
of Figure 1 and illustrating the extinguishing of.
ing, but as they emerge from the lower end of the
an are drawn between contacts of Figure 1;
- electrode (downwardly as viewed in the drawings)
Figure 8 is a diagrammatic view illustrating a
they bend-or curve laterally away from the axis in
practical application of the principles of the in
all directions, toward the right and toward the
vention illustrating the rupturing of an are drawn 30 left in the plane of the paper, and toward and
between contacts as they separate;
from the observer, .etc., as_is well known, and
Figure 9 is a longitudinal sectional view of a
thence ?ow back to the other end of the electrode
structure embodying the invention and of a form
I. The ?eld may, for convenience, be referred to
such as would be suitable to use in some cases in
as being of funnel form in the space between the
actual practice;
contacttips.
,
Figure 410 is a view generally similar to Figure 9,
A return magnetic circuit is provided for the
but illustrating a modi?cation;
lines 16, in ‘the form of a tube I1 of ferrous or
Figures 11 and 12 are views generally similar to
other magnetic materiaL-surrounding the winding
Figure 9lor Figure 10 but illustrating modi?ca
and having its lower annular end generally in a
tions using permanent magnets instead of the 40 plane with the contact tip 2; and having its other '
panying drawings, in which:
strated;
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e
_
electro-masnets of those ?gures;
_
end joined to the core I by a connecting element
.
Figures 13 and 14 are views illustrating further
modi?cations in which the principles of the in
electrically insulates the tube I‘! from the con
vention may be embodied;
necting element I8.
,
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Figure 15 is a view generally similarto Figure 1,
but illustrating two pairs or sets of contacts in
series with each other for breaking an ‘electric
circuit at two points;
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I8. An insulating sheet of insulating material 6
_
"
With the winding II energized and the ?eld as
described present, if the'electrode 3 be raised by
the handle 5 to engage the tip 4 with the tip 2.
current will ?ow through the electrodes as de—
Figure 16 is a view similar to Figure 15, but 11- .
scribed; and, upon withdrawing the electrode 3
lustrating the parts more as they would be ar 50 by the handle, an arc will be drawn between the
ranged in practice and showing the are at the two
contacts being broken as the contacts separate;
Figure 17 is a longitudinal sectional view of a
_
tips 2 and 4 which will be in the said magnetic
?eld; and the ?eldand arc will react upon each
other as presently to be described.
It is immaterial to this invention whether the‘
double-break contact of the type illustrated dia
grammatically in Figure 16 and illustrating the 65 lines of magnetic force be considered as ?owing
downwardly (as viewed in the drawings) and
parts more as they would appear in actual prac
tice and including an enclosing housing structure
through the ,electrodel and as bending diverg
therefor.
ingly in all ‘directions laterally away from the
With reference to the diagrammatic apparatus
axis of the winding: or whether the lines of force
of Figure 1, there is illustrated at I an electrode 60 be considered as ?owing in the other direction
made from steel or other ferrous material, having
and curving or bending inwardly toward the axis.
on its lower end a contact or arcing tip 2 of cop
On the other hand, however, it has bcen discov
per or other metal known to those skilled in the
ered that the direction or polarity of the current
art to be suitable for the arcing contacts of make
in the electrodes and in the are drawn there
66 between is of primary importance, and is at the
I and break contactors.
I
The electrode I is, in this diagrammatic show
foundation of what is believed to be a discovery
ing, stationary; and at 3 is a movable electrode
in this art. Itehas been found that if the elec
which may be of any suitable electrically conduct
trode I within the winding I3 is a positive elec
ing material and having a'contact tip 4 thereon - trode and the other electrode 3 is a negative
confronting the tip 2. .A handle 5 is shown for 70 electrode so that the current ?ows downwardly
moving the movable electrode 3 toward and from
(as viewed in the drawings) and as indicated by '_
the electrode I, as indicated by the arrow on the
the plus and minus‘ signs at the mains 8 and I2
handle to engage the contact tips 2 and 4 to close
and by the arrows I9, the reaction of the mag
an electric circuit, and to withdraw the electrode
netic ?eld upon the current in the arc will cause
8 to draw an arc at the contact tips. A stop ‘I is 76 the arc and any ?ame which may start to de
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velop by ionization of the'air. to be drawn in
it the ?eld strength be still farther increased the
wardly or constricted toward the central axis of
arc will cease or “go out.”
The changes in the form of the arc, tor exam.»
form of a cone with the apex pointed downwardly
ple, those which occur in going irom Figure 2
as viewed in the drawings. For this reason the 5 to Figure 6, can best be shown by high speed
motion pictures projected at low speed. With a.
arc will hereinafter sometimes be ‘referred to as
a cone=shaped are.
standing arcidrawnv inwardly or constricted until
If the polarity or direction of the current be
it goes out, it is dimcult to ascertain, even with
motion pictures, whether the arc extinguishes first
referred to the direction or movement of the elec
trons which compose the current, according to 10 at the apex or ‘at the base of the cone, although
more recent physics, thenin the practice of this
there is considerable evidence to show that when
the arc goes out during the separating movement
invention, the current would be considered as
polarized so that the electrons ?ow upwardly as
of the contacts, to be referred to later, the arc
viewed in the drawings. The polarity of the cur
extinguishes ?rst at the apex of the cone. Susi.
rent may be considered by either de?nition, and 15 motion pictures provide substantial evidence to
show that the cone-shaped arc is a spinning arc,
in either case the base of the cone-shaped are
and practice shows that at least the apex of the
forms at or on that one of the contact tips
(namely, the tip 2 of the drawings) at which the
arc‘is at an exceedingly high temperature because
if allowed to stand for a substantial length of
magnetic lines of force in the ?eld are more near
ly parallel to the magnetic axis, and the apex of 20 time, it volatilizes the metal oi’ the contact tips
and raises the temperature of these tips quickly
the cone forms in that part of the ?eld where
the lines are more divergent with respect to the
to luminous temperature. Based upon the afore
> the ?eld, and take up in appearance the general
axis.
'
said evidence that the cone-shaped are is a spin
In considering the apparatus of Figure 1, it will
ning arc, it is probable that the are is actually of
be assumed ?rst that the rheostat l?-l 5 has been 25 linear form and conveys to the observer the int”
adjusted to provide a magnetic ?eld of such
pression of cone form because of the high velocity7
’ strength that when the electrode 3 is withdrawn
at which the line rotates.
The ammeter l in Figure 1 indicates the
to the maximum distance determined by the stop
amount of current ?owing in the arc;v and as
1, an arc will be drawn between the tips 2-4 and
persist as a standing arc, that is to say, will not so the arc is drawn more and more inwardly toward
be extinguished, in order that the phenomena
the axis or center, for example, in going from
Figure 4 to Figure 6, the current on the ammeter
may be observed. This are can be further de
termined by an initial adjustment of the load
9 decreases and when the arc goes out the cur
rent abruptly falls as indicated by the ammeter.
resistance It. If now the rheostat li-i 5 be ad
iusted so that there is little or no ?eld between 35 This has led to the aforementioned hypothesis
the contact tips, when theyare separated, an are
~ that as the arc is drawn inwardly its resistance
increases, and that it extinguishes or goes out be
such as is illustrated at 20 in Figure 2 will strike
or form as a standing are between the contact
cause its resistance becomes so high that the po
tips. It may strike or form at most any point
tential across the separated contacts is not su?i- ‘
on the tips probably taking the path of least 40 cient to maintain current ?ow- in the are there- ‘
‘{between. With the apparatus of Figure 1, ii the
?eld strength be stronger than that to produce
strength of the ?eld be gradually increased by
resistance. With the are ‘20 standing, ii the
moving the rheostat ll-li to increase the ener
the standing arc of Figure 6 so that the arc goes
out, then obviously when the arc is drawn and
arc and the ?eld will cause the arc to move over 45 the contacts begin to separate, they will reach
a point' of separation at which the arc extin
to the peripheries of one or the other, or both
of the contacts and bulge outwardly laterally
guishes. This, of course, is the manner in which
beyond the peripheries and become elongated or
the invention would be utilized in a make and
stretched. Its form is indeterminate and in dif
breakcontactor {or practical purposes.
ierent instances will have different shapes. For
As is well known in contactor practice, the con
example, it may have the shape shown at it in
tacts separate very rapidly. Using the apparatus
Figure 3 or may have the shape shown at 22 in
of_ Figure 1 to illustrate this, the contact tip 4
would move away from the contact tip 2 very
that figure; and in either case, it will persist as
rapidly; and an observer viewing the formation
a'standing are accompanied by some ?ame. It
gization of the winding IS, the reaction of the
now the ?eld be still further increased by opera 55, and interruption‘ of _ the arc would observe visibly
tion of the rheostat ll-li, or if a still stronger
a short arc, such as that shown at 23 in Figure
'7 of the cone shape with the apex downwardly, .
?eld is present when the contacts separate, the
and his retina would retain the impression of this
arc and whatever ?ame is present, instead of
short arc with a space between its apex and the
being driven still farther outwardly laterally from
the contacts and becoming larger (as might be 60 tip 4. In Figure 8 is illustrated diagrammatically
an arrangement of parts suitable for embodiment
expected-from a knowledge of prior magnetic arc
in a practical make and break contactor to con
blowout practice) are drawn inwardly toward the
trol a load circuit. Current is supplied by positive
axis of the ?eld and become shorter and stand
and negative supply mains 8 and I2. When the
as a persisting arc, accompanied by some ?ame,
upon the intermediate or generally central por ‘5 movable electrode 3 is raised to engage the contact
tips 2 and 4, current ?ows from the main 8
tions of the contact this and become “cone~
through a series winding 24 around a ferrous elec
shaped" as shown for example in Figure 4, with
the apex of the .cone relatively blunt or trun
trode or core 25‘ to the contact tip 2 and thence
to the tip 4 and to the electrode 3, and thence
cated. If the ?eld strength be still iartherin
creased, the ‘arc and ?ame‘ will be drawn in 70 through a load 20 to the main H. The winding
wardly still farther and the apex of the cone Y f2! produces the magnetic ?eld. When the elec-_'
trode I is withdrawn and moves the tip 4 pro- '
and its diameter generally will become smaller
I gressively farther from the tip 2, the are 21 is
_ as indicated in Figure 5. It the ?eld strength be
drawn therebetween. As the-contacts separate,
still farther increased. the diameter or the cone
_willbecomcverysmallaeshownin1"igure6and " this are takes up the. form 0! a cone as illustrated.
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and a point is reached in the movement of the
In Figure 9 I have illustrated the parts shown
tip 4, namely at 5A, at which the apex of the
diagrammatically in Figure 8, but more as they
would appear in actual practice. A steel or other
cone is constricted substantially to'a point or to
a very small cross-sectional area, this being the > - ferrous-core 29 has a shank 3b of reduced diam
position at which the maximum attenuation
eter thereby providing a shoulder St. The return
which the arc apex can attain is reached, so that
magnetic circuit 32 is in the form of a cup, and
the bottom of the cup has a perforation 33
movement of the .tip beyond the position 6A
causes the arc to ‘extinguish. It will therefore be
through which. the shank 3b is projected. The
readily appreciated that, whereas in prior prac
J shank is projected not only through the perfo
tice the arc drawn between contacts completely 10 ration 88 but through a corresponding bore 34
bridges them and stands for'an interval of time
. in a supporting panel 36 and a nut 39 on the
while it is being extinguished, here the arc never
shank outwardly of the panel; when drawn up
completely bridges the contacts in their open potight,‘ mounts both the core 29 and the return
sition. As a consequence the arc exists for such
magnetic circuit 82 rigidly upon the panel 35.
a short interval of time--a_fraction of the time '15 The winding 3'?! passes through aligned perfo
during which the contacts areopening-that
rations or bores 38 in the panel and in the bottom
although the arc, particularly at the cone apex is
of the cup and is wound around the core 29 se
' very hot’ and capable of heating the metal to the
volatilization temperature, there is not su?cient
time for the heat of the arc to'raise the metal
of either tip 2 or £3 to the volatilizing or- melting
‘point; and as the consequence, the tips, even
after thousands of operations, do not develop
thereon the pitting and roughening which inevit
cured at its lower end as viewed in the drawings
to a clip device 3t having electrical contact with
the arcing tip 2. Otherv parts and the mode of
operation, as will be apparent, will be the same as
those of Figure 8.
,
In Figure 10 is illustrated a modi?cation of
the form of Figure 9, showing a di?erent con
25 struction of return magnetic circuit. A disc {in
ably occur after a few operations in prior‘ con
tactors in which the arc completely bridges the
contact gap and stands bridging the contacts be
fore it is extinguished. The contacts therefore
have a useful life prolonged enormously beyond
that of the contacts of prior magnetic arc blow 30
out contactors.
With an arrangement such as shown in Figure -;
of ferrous material has a perforation ill therein
through which the shank 30 of the core 29 is
projected whereby ‘the nut 36 will mount the core
and the disc $8 on the supporting panel‘ 35.
Riveted or otherwise secured to the disc 130 is a
plurality of ferrous rods or posts 42'—1i2 project~
ing therefrom in the general direction of the
, 8.in solid line, the magnetism produced in the ’ core 29. A ring of ferrous material 43 is secured
core element 25 produces a ?eld between the con
to the outer ends of these posts in any suitable
tacts for extinguishing the arc and returns to 35 manner, for example, by screws 46 projected
‘the other end of the core 25 through the air;
through the ring and threaded into the ends of
and, with such air'return magnetic path, current
the posts. The ring {53 has a central perforation
of great amperage can be broken and the arc
or opening 65 surrounding the magnetic axis and ,
extinguished without the development of ?ame
‘ ~
preferably, but‘ not essentially, coaxial with the
'beyond the con?nes ,of the contact tips them 40 magnetic core 29 and disposed so that the flux
selves; and the arc goes out without the‘ usual
emanating from the lower end of the core 29 rs
' explosive sound; and the'provision of an arcing
chamber, arc shields, and the like as found nec
'viewed in the drawings will form a funnel ?eld
in the arcing space between the contact tips 2
and ll having the characteristics above described.
essary heretofore, are not. needed; and therefore
my invention is not limited to the employment of
By changing the lengths of the posts G2, the po
sition of the ring 63 may be varied. The position
As stated above, however, to develop the full‘
for this ring illustrated in Figure 10 will be suit
advantages of the invention, a suitable density
able and the principles of the invention will be
or strength of magnetic ?eld must be provided by
expressed with it in this position, but because
the winding, and such ?eld can be produced with 50 of variable quantities, which inevitably will be
fewer ampere turns in the winding. if a return
present in such a structure, the optimum position
path for the lines of force in the ?eld made from
for‘ this ring may be nearer to or farther from
ferrous material be provided. Also the form of
the end of the core 29. In some cases, the mag~
the ?eld in the arcing gap can be pro-determined
netic ?eld which can be produced by a permanent
more accurately, which in some cases may be 55 magnet will be sufficient to draw the arc inwardly
found to be desirable, if a return magnetic path
and to extinguish it, and in Figures 11 and 12, I
is provided; and such a return path is indicated
have indicated a structural arrangement by
in Figure 8 in dotted lines at 28 corresponding . which this may be accomplished. In both ?gures.
generally to the return path l'i-i8 of Figure 1.
as will be obvious, the winding to produce the
In Figure 8 is indicated an “actuating appara 60 ?eld is not needed and has been omitted.
tus” for causing the electrode 3 and the contact
Referring to Figure 11, there is shown gen
tip 4 to be moved toward the contact tip 2 and
erally at 136 an electrode of copper or other elec
retracted therefrom for the purposes described,
trically conducting material, in tubular form,
and this has been done to simplify the drawings
closed at its lower end (as viewed in the drawings)
and description because such actuating apparatus 65 and having a contact tip 2 thereon. The electrode
is so well known in this art; but it may be added
£16 has a shank li'l projected outwardly through
here that in practicing the invention with such
a perforation in the supporting panel 158 and
well known actuating apparatus, it is'not neces
threaded to receive a nut 49; and outwardly be
sary to provide any special features in such actu
yond the nut 69, a terminal 50 may be mounted
ating apparatus to cause the electrode 3 to be 70 on the shank by nuts 5i. The reduction in diamretracted more rapidly than in common practice
eter to provide the shank 4'? provides a shoulder
in make and break contactors, nor to separate
52. Within the tubulanelectrode 66 is a perma
the contact tips a greater distance than in com
nent magnet 53, the line of force emanating from
mon contactor practice, to effect interruption of
the lower end of which provide the arc extinguish
the arc while the contacts are moving‘ apart.
76 ing field above described. A return magnetic cir
a ferrous return magnetic path.
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2,411,893
cult is provided shown‘ generally at 54 comprising
a relatively thickened ferrous disc 55 having a
perforation 55 therein preferably co-axial with
the magnet 53; and a tubular ferrous side wall
51 ‘connected thereto and extending upwardly to
and connected to a ferrous disc 58 which has a
3
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10
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gized magnetic circuit for producing the arc in
terrupting ?eld and that other forms of such
permanent magnets will now readily occur to
those skilled in this art; for example, in Figure
9 or Figure 10, those parts, or some of them,'which
are referred to above as comprised in the return
perforation therein encircling the shank 41 of the
magnetic circuit maybe made from permanently
electrode. A thimble of electric insulation mate
magnetized metal for this purpose. In some of
rial 59 lies between the disc 58 and the electrode
the foregoing ?gures, where windings are utilized
45 and is engaged by the shoulder 52. As will be 10 to produce the magnetic, ?eld, the magnetic core
apparent, when the nut 49 is drawn up tight, the
within the winding has been shown to be of ap»
shoulder 52 draws the thimble against the disc
proximately the same cross-sectional area as that
58, and both the electrode 48 and the return
of‘ the contact or contact tip. These ?gures
magnetic circuit 54 are thereby rigidly mounted
therefore might be thought to suggest that the
upon the panel 48 in functioning positions. In 15 field produced by the winding should emanate
explanation of the insulation 59, it should be
equally or substantially equally through all parts
pointed out here that, in all of the arrangements
of the contact tip. This is not essential as has
herein illustrated having return magnetic» cir
been indicated generally by the arrangements
cuits, the outer or movable electrode is illustrated
of Figures 1i and 12 utilizing permanent mag“
as below the magnetic circuit; but that the ar 20v nets; and is further shown not to be essential by
rangements will function just as well in any'other
the arrangements of Figures 13 and 14 which
position, for example, upside down; in which lat
v have been found to be practicable and to satis
ter instance the return magnetic circuit maybe
'factorily embody and express the principles of
a lodging place for foreign matter or objects from
the invention.
any source, which might electrically bridge the 25 In Figure 13 the-iron core 69 is of reduced
movable electrode and the magnetic circuit; and
cross-section and lies longitudinally within an
if the said insulation were absent, a short circuit
between the electrodes through the return mag
netic circuit might be set up. It will be noted
that the ‘insulation 59 is located so remotely from
the movable electrode and in a sense within a
_ structure, that it cannot be unintentionally
bridged; but since its function can be performed
by a suitable gap in the return magnetic‘circuit
at almost any other point, the exact location
given it in Figure 11 is not essential.
electrically conducting electrode 10 through
which the current from the positive main ?ows
on its way to the contact tip ,2. The ?eld pro
ducing winding ‘H surrounds the electrode 10.
_ Here as will be apparent, the greater part of
the ?eld producing ?ux flows out of the lower
end of the core 69 and therefore .in general
through the central or axial portion of the con
tact tip 2.
, ,
In Figure 14 the magnetic core 12 is in the
In Figure 12 a ‘copper or like electrode 60 is
form of a sleeve, surrounding an electrode 13
provided having the arc tip 2 thereon, and at its
through which the current ?ows to the tip 2;
upper end is of reduced diameter to provide a
and here as will be apparent the ?ux producing
shank 6| projected outwardly through the sup 40 the arc extinguishing field emanates from the
porting panel 62 and providing a shoulder 63 on
end of the sleeve at portions of the contact tip
the electrode. A nut 64 is threaded on the shank
2 generally near its periphery. In both Figures
5| and outwardly beyond it are nuts 65 for mount
13 and 14 the ?eld producing windings ‘II and
ing a terminal 66 on the electrode. A permanent
14 are shown, as a further modi?cation, as
magnet 61, in this ?gure in the form of a tube, 45 energizable independently of the main current
is telescoped over the electrode 50 and the upper
through the are.
end (as viewed in the drawings) is formed with
The invention as described above relates to the
a flange 68 which ?ts over the shoulder 63. A . breaking of a circuit at a single pair of contacts.
return magnetic circuit is again provided com
The structure of the means or mechanism for
prising, as in the form of Figure 11,}a disc or 50 moving the contacts to close the circuit and sepa
head 55 having a perforation 56, and connected
rate them to break it, have not been shown in
to a side wall 51 whichmay be tubular, and which
asmuch as such means are so common-place and
at its upper end is provided with a disc or head
so well known in the art. In mostvcases as is
58 encircling the shank 5!, between the flange 58
well known, the electrical connection to the mov
of the magnet and the panel 62. When the nut 65 able electrode for example, the electrode 3 in
64 is drawn up tight, it will mount the magnet
Figure 8 or Figure 1, must be a flexible connec
5'! and the return magnetic circuit and the elec
tion as indicated at I I. To avoid the necessity of
trode 50 rigidly upon the panel 62 with the mag
netic circuit and the ?eld in functioning positions.
such ?exible connection, there has been developed
in the art numerous types of construction by
.As will be apparent in both the forms of Figures 60 which the electric circuit is broken concurrently
11 and 12, the magnetic ?eld produced by the
at two points in series with each other in the
permanent magnets will have the form described
circuit. Figure 15 illustrates such an arrange
in connection with Figure 1 for causing the arc
ment embodying my invention in an apparatus to be drawn inwardly and take up the form of
by which the action may be observed. Shown
a cone between the arcing tips 2 and 4 and to be a generally at 15 and ‘I6 is one pair of contacts
extinguished thereby. “
and at 17 and 18 another pair, the contacts 16
As stated hereinbefore, the return magnetic
and 11 being mounted upon a connector 19 and
circuit is in all cases not essential and therefore
reciprocable by a handle 80 connected to the
with the permanent magnet forms of Figures 11
connector 19. When the connector 19 is moved
and 12, it may be simply omitted; and the making 70 upwardly to effect engagement of the pairs of
of any structural changes occasioned by its omis
contacts. current in a circuit to be controlled
sion is believed to be well within the knowledge
?ows from a positive main 8| through an am
of those skilled in the art. It is believed that
meter 82, to a magnetic pole piece or core 83
Figures 11 and 12 and their descriptions disclose
and thence through the contacts 15 and ‘I6,
sufficiently the utilization of-a permanently ener 75 through the connector 18. through the contacts
l
iii:
'
9,411,893
.
-. or core 84, thence through a current limiting
load 85, to a negative main 86; and when the
connector ‘i9 is retracted,.arcs as indicated at 81
,
- stretching it until it breaks; and this improve?
ment is believed to be due to the fact that the
two arcs are in series.
In Figure 16 is illustrated diagrammaticallya ‘
andv 8b, are drawn between the respective pairs
of contacts.
12
tendant upon breaking‘ an arc in prior devices in
which the arc is ruptured by elongating or
if and .18, ‘and through a second magnetic pole
'
general arrangement of parts which might be
Magnetic held’: in the arcing gaps between the
used in an actual double-break contactor‘wherein.
contacts are produced by windings on the said
it is intended that the arc shall be extinguished
cores, the energizing current flowing from the
main-‘8i through a winding 89 on the core 83, 10 each time that the contacts separate and not per
sist or stand at any time. Here-windings on cores
and thence through a winding 9d on the core 3%,
S3 and 913 are in series in the main circuit be
and thence to the negative main 86, through a
tween mains gtand 96, and in series with the
'rheostat 9i-92. At suitable load 85 initially ad
arcs, and the ampere turns thereof are predeter
justed . and at suitable energizations of these
mined so that there will be a sumciently strong
windings, the arcs 8i and 88 will be standing arcs
?eld to extinguish the arcs in every case. When
and may be observed. The are 871 will again be
the connector 9i has engaged the contacts, and " >
drawn inwardly and become cone-shaped with its
then withdraws the contacts ‘i5 and ‘ll, the arcs
apexpointing downwardly as described herein
_ ill and 83 form as described above, but by the time ‘A
before,-but the current is ?owing in the opposite
direction through the arc 88, and its form and 20 the contacts it and ii reach the positions in- ,
.
dicated generally at 76A and WA, the arcs are
characteristics will be different.
'
‘ The present‘lnvention has thus far been 'oeé' ,
extinguished. The are t‘! becomes cone-shaped
scribed as~relating particularly to the formation
as illustrated and as described more completely,
above, the cone apex of which is to the eye of the
anol' extinguishing of an arc to interrupt a cir
cuit'at one point, or at one pair of contacts. In 25 observer, spaced from the contact ‘86.
The foregoing description has been directed to
, the embodiment of Figure 15 where the circuit is
the utilization of the invention with uni-direc
interrupted at two points, or two pairs of con-'
tional or direct current, but it is applicable also to
tacts, the invention relates particularly to the
making and breaking alternating current circuits.
production and extinguishing of the arc 8'5 as
drawn between one pair of contacts, and its 30 In connection with alternating current, the
double-‘break arrangement shown diagrammat
functions in breaking the circuit in cooperation
ically in Figure 16 is' preferred because the cur
with the are $8 drawn at the other pair of con
rent periodically changes in direction. When the
tacts; and therefore only a brief discussion of
current is .?owing in one direction, the cone
the are 83 will for this reason be given in this
patent; A more complete discussion of arcs cor 35 shaped are forms at one pair of contacts. When
the current reverses and ?ows in the other di-‘
responding to the arc 88 will be found in my co
pending application, Serial No. 493,847,'?led'July , rection, the cone¢shaped arc obviously will be
’
8‘, 1943. For purposes of economy in manufac
,_~>-f9rvme'd- at the other pair'of contacts.
‘
ture, convenience of making replacementsyre
Thus the _
a'dvantages described ‘above of having the cone
pairs, etc., it is desirable for the structure and '
shaped arc in series with the other arc to con
arr'angement of parts at both pairs of contacts
to be duplicated structures as nearly as practi
tribute to the improved- breaking of both arcs are
always present at both pairs of contacts. The
cable.
observable visible character of the arcs with al
'
'
The two arcs d? and 88 will therefore usually
be produced under like conditions; and because
.of theremarkable extinguishing characteristics
45
ternating current ‘introduces evidence to show
that 'the self-extinguishing characteristics of the
cone-shaped arc predominate when the two arcs
be predetermined to meet the optimum require
are in series because the arcs that are visible to
an observer appear as cone-shaped arcs at both
ments of that arc.
pairs of contacts when the current is alternating.
~of the cone-shaped ‘arc B‘L'both structures will
Under such equivalent or
duplicate conditions, jgand proceeding experi-‘ 50 Similarly, when a single pair of contacts is used
mentally with the apparatus of Figure 15, and
producing standing arcs, and gradually increas
ing',;the strength oi-the ?elds by' the rheostat
Sig-‘~92, the arc 88, at low ?eld strength will tend
to befrepelled" outwardly away from the space
between the contacts somewhat as illustrated in
Figure
shaped
the arc
sists in
to break an alternating current circuit, a cone
shaped arc corresponding to the arc 81 tends to
develop duringv one half cycle, and an arc corre
55
sponding to the are 88 tends to develop during
the succeeding half cycle. The eifect. is di?icult
for the eye to observe, but in general it is be
lieved that the arc extinguishes upon the develop
3 and described above for the cone--v
ment of the cone-shaped arc.
arc. As the ?eld strength is increased,
in practice, upon. breaking an alternating cur-v
88 is drawn inwardly and standsxorjper-v :
the space between the contacts; While 1 ,rent circuit by thev utilization of my invention,
‘even when the current amperage is as high or
' 'wardly
is going
and-acquired
on, the are
its 87
cone
hasform,
been and
drawn
it‘be-L;-,
"in;
even higher than the ‘maximum continuous cur
' rent carrying capacit'y'of the‘ closed contacts, the
comes more and more attenuated as‘ described
. arc‘or-arcs extinguish so "easily" and with so little
- ,‘above in going from Figure 4 to Figure 6. As the
‘ cone-shaped are at thus becomes more and more‘ 65.. observable phenomena of any kind, that it is dif
ficult in? some instances to describe from observa
"attenuated, the ammeter $32 indicates that the
tion the character of the‘ are or arcs at the in-.
"current in both arcs is falling just as when the
cone~shaped arc was alone in the circuit;' and
stant of rupture.
- ,
Among the foregoing forms and modifications
- the current on the ammeter ultimately abruptly
of the invention, it is shown that the arc ?eld
falls to zero and both arcs go out. Since the
may be produced by a winding energized inde
are 88 is substantially con?ned to the space be~
pendently of. the arc or by a winding in series with
tween the contacts, as referred to, and since the
the arc. In the latter case, as the resistance of
current ?owing in it has ben reduced as described,
its extinguishment also occurs without the usual
the arc increases, the current reduces and the
explosive sound and without the usual ?ame at
field will weaken. In some cases, therefore, it .
2,411,893
may be desirable to utilize in the magnetic core
14
scoped over the sleeves I01 and detachably se
cured by means, not shown but well known in the
art, to the panel I00. The housing thus holds
the insulator I09 and the sleeves I01 in position.
The housing H0 is provided with bores III—I II
‘axially aligned with the cores I02-I02 which
function as guides for guiding the reciprocatory
movement of the lower contacts II2~—I I2. The
contacts II2-II2 are electrically connected by
or magnetic. circuit, steel having a substantial
degree of magnetic retentivity to insure that
there will be a strong enough ?eld even at the
moment of extinction of the arc.
A gap in the magnetic circuit such as that pro
vided at the insulation 59 of Figure 11 can be pro
vided in any of the forms having return magnetic
circuits, if for any reason it is found to be desir-'
able. Obviously, return magnetic circuits, such .10 a connector H3 and means is shown at II 4 for
for example, as those described may be provided '
for the forms of Figures 13 and 14 and also for ,
reciprocating the connector H3 and the contacts
II2-II2. The contacts are illustrated in the
the double contact forms of whichFigures 15 and
fully open positions. The arrangement will be
16’ are illustrative examples, and as indicated in
seen to be similar to that of Figure 16 and its op
dotted lines at 98 for the form of Figure 16. In 15 eration to be substantially the same as that of
use with alternating current circuits it may be
the apparatus of Figure 16.
desirable to laminate or slot the ferrous parts of
Using this contactor as a double-break direct
the magnetic circuit to reduce the generation of
current contactor, either one of the windings
eddy currents therein. This is so well understood
may beconnected to the positive supply main,
in this art as not to warrant complications in the 20 and the two windings will be in series. There are
drawings or prolixity in the speci?cation to illus
approximately three-and-one-half turns in each
trate and describe it.
'
winding. The ?eld strength at each set of con
It will be apparent from the foregoing that in ' tacts will be determined by the amperage ?ow
order to draw the arc inwardly and extinguish it,
ing in the windings. With a non-inductive load
there must be a ?eld strength above a certain 25 circuit at 230 volts across the supply mains, the
minimum; and that this minimum ?eld strength
above described coneeshaped arc will be devel
is in general-greater than has usually been em
oped and extinguished at one of the sets of con
ployed heretofore in prior arc interrupters. A
tacts as the contacts move apart when the ?eld
?eld strength greater than this minimum is, as
strength is that produced by 30 amperes in the
a fact, not detrimental. The ?eld strength 30 circuit, and therefore, in the windings. In other
therefore: does not have a critical value.
words, approximately 105 ampere turns are
In practice there will, therefore, be an optimum
enough in this contactor to provide a cone are
?eld strength which will lie between this mini
producing and extinguishing ?eld strength. This
mum and a’ maximum, which maximum, will be
?eld strength is in the above mentioned optimum
determined by economical considerations repre 85 ?eld strength range, and accordingly, this ?eld
sented by the size and cost of the winding and
strength vmay be decreased substantially (by
associated parts. Even this optimum ?eld
fewer turns or lower amperage) without losing
strength will be different in different structures
the arc forming and extinguishing characteris
and for different amounts or amperages of cur
rent to be interrupted. My invention, therefore, 40
is not limited to any particular ?eld strength, in
asmuch as in any instance, all of the advantages
thereof will be expressed with a considerable
may be successfully interrupted for thousands
01' operations before impairment of the carry
ing capacity of the contacts becomes perceptible.
Subject matter illustrated and described herein
but not claimed is being claimed in my copend
the ?eld strength (to comply with the statutes),
I have illustrated in Figure 17' a contactor drawn
to scale (in the original drawings) from a working
specimen embodying the invention, and it will
7
- I
For repeated intermittent operation cur
rents as high as one hundred or more amperes
make this disclosure de?nite and sufficient as to
The contactor of Figure 1''! is a double break
contactor, the two halves of which are duplicates,
For higher load currents in the circuit, stronger
?elds will be produced and the larger amperages
will accordingly be interrupted in the same man
ner.
range of ?eld strengths. In order, however, to
now be described.
tics described.
50
ing application, Serial No. 493,847, ?led July 8,
1943.
'
Although I have described my invention with a
,. and either half of which may be used alone as a
certain degree of particularity, it is understood
single break ‘contactor. A supporting panel I00
that the present disclosure has been made only
has recesses in its face in which are seated ferrous 55 by way of example and that numerous changes
discs IOI—l0I. Ferrous cores I02—I02 extend
in the details 01' construction and the combina
through the panel I00 and by means of nuts
IOI-I03 on threaded shanks of the cores,’ the
tion and ‘arrangement of parts'may be resorted
to without departing from the spirit and the scope
cores and the discs are rigidly mounted upon the I or the invention as hereinafter claimed, '
I claim as my invention:
60
lower ends of the cores, have electrical connec- >
In a magnetically quenched circuit breaker‘
,panel. Contact tips I0l—I0l, mounted on the
tion with clip devices I05-I05 to each of which
having two relatively movable contacts, the
one end of a winding I00 is connected, the wind
method of quenching the are created when said
ing helically surrounding the core and the other
contacts open, said method comprising magnet
‘ end of the winding passing outwardly through 65 ically forcing the are at the instant of its crea
' - the panel I00 where it may be connected to an
electric circuit as described hereinbefore. A re
tion inwardly toward a central zone between the '
separated contacts thereby preventing the arc
turn magnetic circuit, comprising a sleeve I01 and
from materially lengthening itself by ?aring out
having on its lower end a'ring I08,,surrounds the
wardly beyond the sides of the contacts, and mag
winding and at its upper end is spaced from the 70 netically restricting the cross-sectional area of
disc III by an insulator I09. As will be seen, the
the said are and thereby increasing the resistance
disc‘ IIII is a part of the return magnetic circuit.
of the said are without materially increasing the
An external enclosing housing IIO made from in
length thereof for extinguishing the arc.
sulating material is provided having recesses tele
GERHARD-W.» PETERS.
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