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Патент USA US3020384

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Feb. 6, 1962
G. D. TOOTELIAN
3,020,374
CIRCUIT BREAKER moms CONTACT CONSTRUCTION
Filed July 2, 1959
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States Patent 0" ice
3,.GZ9,374
Patented Feb. 6, 1962
1
2
tobias the arcing contact in a direction to oppose blow
3,020,374
off force.
CIRCUIT BREAKER ARUING CUNTACT
.
~
Accordingly, a primary object of my invention is to
CONSTRUCTION
provide a novel structure for opposing the blow-off force
George I). Tootelian, Brooinall, Pa., assi'gnor to I-T-E
applied to an arcing contact.
Circuit Breaker tlornpany, Philadelphia, he, a corpo~
ration of Pennsylvania
Another object of my invention is to do away with
the necessity of powerful springs, for biasing an arcing
Filed July 2, 1959, Ser. No. 824,583
8 ?laims. (Cl. 200-146)
contact toward its engaged position.
'
‘_ A further object of my invention is to utilize the bias
ing spring of an arcing contact as a solenoid winding for
My invention relates to an arcing. contact construction
wherein the arcing current sets up a magnetic ?ux to
. moving an arcing contact in a direction against the blow
drive the arcing contact into engagement with respect
to its cooperating contacts and counteracts the‘normal
blow-cit forces tending to open the arcing contact.
cit force applied thereto during current conduction
through the arcing contact.
‘
A stillfurther object of this invention is to insulate an
arcing contact from the contact arm carrying the arcing
In the circuit breakers of the type set forth in US.
Patent No. 2,891,123, issued June»16,~1959, entitled
“High Speed Circuit Breaker” in the name of Chailiss I.
contact and electrically connecting the arcing contact
to the contact arm by circuit means which will operate
to exert a force upon the arcing contact in opposition
to the blow-oil force applied thereto.
These and other objects of my invention will become
Clausing and assigned to the assignee of the present in
vention, the movable contact is normally constructed of
a main movable contact electrically connected in parallel
with an arcing contact. The movable contact arm is
normally controlled and constructed so that when the
apparent from the following description when taken in
connection with the drawings in which:
circuit breaker is operated‘ to its engaged position, the
FIGURE 1 shows a ?rst embodiment of my novel
movable contact arm structure wherein the biasing spring
rent path remaining in parallel therewith which includes 25 for biasing the arcing contact is used as a solenoid wind
the arcing contact. Therefore, there is no arc drawn
ing under arcing conditions.
to the main movable contact. As the disengaging opera
FIGURE 2 shows a second embodiment of. my inven
tion continues, the arcing contact ?nally moves away
ti'on. wherein the solenoid need not act as the main bias
main movable contact will ?rst disengage with a cur
from its cooperating contact and an arc is then drawn
to the arcing contact which is speci?cally constructed 30
to withstand arcing duty.
During closing, the arcing contact will normally close
ing spring for the pivotally mounted contact.
‘
FIGURE 3 is similar to FIGURE 2 and shows the
movable contact arm in partially and fully disengaging
position.
the circuit ?rst and is followed by the movable contact.
'
FIGURE 4 shows a further embodiment of the inven~
Therefore, when the movable main contact closes, the
circuit has already been completed and the main movable
contact is subjected to very little closing duty.
tion Where the auxiliary spring is concentric with the
During the opening operation, it is desirable to have ,
the main movablecontact open to a substantial distance
ll} of conductive material is pivotally mounted on pivot
biasing spring.
.
Referring now to FIGURE 1, a movable contact arm
12. ~A main contact 14 is pivoted to arm 10 at pivot
before the arcing contact opens. However, there is a
16 for limited angular motion. The upper end of con~v
40
substantial blow-off force exerted upon the arcing con
tact arm 10 carries an arcing contact 18 which is mounted
tact which normally is pivotallymounted on the movable
‘to arm that pivot 2d. The pivotal connection between
contact structure carrying both the main movable con—
arm 16 and arcing contact '18 is an insulated connection
tact and the arcing contact. These blow-off forces can,
and is formed of a main central pin 22 and an outer
in a circuit breaker carrying large load currents and
insulating cylinder 24. A relatively stationary contact
which are subjected to large short circuit currents reach
for cooperating with main contact 14 and arcing contact
sizable magnitudes of force and exert a considerable
18 is partially shown as stationary contact member 26
opening force on the pivotally mounted arcing contact be
and includes contact surfaces 28 and 31 for cooperating
fore the movable contact has reached a sufficiently open
with the main movable contact 14 and arcing contact 18
position. For this reason, the arcing contact is backed
up with large springs which normally bias toward the
respectively.
contact engaged position. When, ‘however, the blow-oil?
force in a particular circuit is large enough, it is not
feasible to provide biasing springs large enough to with
stand the bloW-o? force.
I have discovered that I can utilize the energy of
the arcing current to help withstand the blow-oil force
by causing this currentv to operate a solenoid carried
by the movable contact and which includes a magnetic
member connected to the pivotally mounted arcing con~
tact. If desired, the normally used biasing spring may
arm 10.
60'
be connected to act as an electrical winding or an aux- '
iliary'means may be provided.
Thus; I can utilize a ,
biasingspring which is of‘ a relatively high conductivity
I
I
The arcing contact 18 has a rearwardly projecting
portion 30 which is positioned under an insulated ad
justable stop 32 which is formed by a threaded screw
member carried by frame 10. The arcing contact 18
is then biased toward engagement with stop 32 by a
spring 34 which is preferably a beryllium copper spring.
The beryllium copper spring is electrically connected at
its ends between arcing contact 18 and movable contact
'
~
In accordance with the present invention, the relatively
movable non-magnetic member 38 and a magnetic plung
er 40 are positioned within spring 34 and ‘are axially
movable therein. Accordingly, when the movable con
tact arm to is moved toward a disengaged position by
material and insulatethe pivotaliy mounted arcing con
operating means 42, the main movable contact 14 will
tact from the contact arm; The biasing; spring is then
disengage with respect to stationary contact 28 while
electrically connected between the arcing contact and the
the arcing contact 18 will remain engaged with cooperat
contact arm so that under arcing conditions, the current
ing contact '31 because of the biasing spring 34 which
is carried at least in part by the spring.
biases the arcing contact toward its engaged position.
-A magnetic core which is mechanically connected to 70 The current ?ow will now form a relatively U-shaped
the arcing contact is then acted upon by the current
path going through the stationary arcing contact 31,
through this spring which acts as a solenoid winding
arcing contact 18, spring 34 land to the main contact
3,020,374
3
4
arm 10. This U-shaped current path will cause a blow
FIGURE 1, a magnetic plunger 66 which is axially
oii action against arcing contact 18 tending to rotate it in
clockwise direction about pivot 20 and thus open the
circuit before su?icient clearance is achieved between
the main movable contact 14 and its cooperating con
movable within spring 56 serves as the solenoid plunger
for the solenoid winding formed by spring 56.
Accordingly, when current is established through the
arcing‘ contact, this current flows from arcing contact
tact 28.
18 through spring 56 to contact arm 19 to establish a
The only force counteracting this blow-off force in
the past has been the biasing spring 34. When, however,
the current magnitudes are sufficiently high, this spring
magnetic field which will drive plunger 66 upwardly.
This will force plunger 68 into engagement with rear
force will be overcome prematurely.
thereby drive it in a counterclockwise direction and rein
In accordance with the present invention, when the
main contact 14 disengages, the arcing current ?ows
force the biasing force of main biasing spring 58.
In the foregoing, I have described my invention only
in connection with preferred embodiments thereof. Many
through spring 34 so that the spring acts as a solenoid
wardiy extending portion 30 of arcing contact 18 to
variations and modi?cations of the principles of my in
rial will be drawn upwardly with a strong force into 15 vention within the scope of the description herein are
obvious. Accordingly, I prefer to be bound not by the
engagement with member 38 which, in turn, engages
winding. Accordingly, the plunger 40 of magnetic mate
the rearwardly projecting portion 3a of the arcing con
speci?c disclosure herein but only by the appending
claims.
tact to drive it in a counter-clockwise direction and against
I claim:
the blow-off force.
1. A movable contact arm for a circuit breaker; said
FIGURE 2 shows a second embodiment of my novel 20
movable contact arm being movable between an engaged
invention wherein numerals similar to those used in
FIGURE 1 identify similar components. The embodi
and disengaged position with respect to a cooperating
contact; said movable contact arm carrying a main con
ment of FIGURE 2 diifers from the embodiment of
tact and an arcing contact; said arcing contact being
FIGURE 1 in having the auxiliary blow-off force means
independent of the biasing spring 34 of FIGURE 1 so 25 pivotally connected to said contact arm; abutting means
mounted to said movable arm for limiting the motion
that the material used for the biasing spring may be se
of said arcing contact with respect to said contact arm;
lected to have the best spring properties. In FIGURE
2, biasing spring 34 is not shown in order to simplify
the drawings, but is present and operates in the same
said arcing contact being electrically insulated from said
contact arm at the pivot point; a biasing means for nor~
FIGURE 2 shows a projecting arm 44 which is directly
connected to arcing contact 18 to be rotatable there
with. The end of arm 44 is terminated by a magnetic
mally biasing said arcing contact towards an engaged
position with respect to said cooperating contact; an
auxiliary means for imparting additional force to said
arcing contact in the direction of the force imparted
by said biasing means; said auxiliary means electrically
button 46. Magnetic button 46 is positioned adjacent
connecting said arcing contact to said contact arm for
an iron core 48 and separated therefrom by an air gap
and core 48 is rigidly connected to contact arm 10. A
spring member or coil 50 which is of a material having
generating a magnetic ?eld; said auxiliary means includ
ing a magnetic means movable against and imparting
a force to said arcing contact responsive to said magnetic
?eld.
manner as described in FIGURE 1 with the exception
of the electrical action.
good electrical conducting characteristics has one end
2. A movable contact arm for a circuit breaker; said
52 mechanically and electrically connected to arcing con 40
movable contact arm being movable between an engaged
tact 18 and its other end 54 mechanically and electrically
and disengaged position with respect to a cooperating
connected to contact arm 10. The spring 50 surrounds
contact; said movable contact arm carrying a main
magnetic core 40 and button 46.
contact and an arcing contact; said arcing contact being
In the structure of FIGURE 2, when the movable
contact arm 10 is operated to move toward a disengaged 45 pivotally connected to said contact arm; abutting means
position and after a disengagement of the main movable
contact 14, a current ?ow is established through spring
50 as seen from the solid line position in FIGURE 3.
This establishes a magnetic'?eld within the spring so
mounted to said movable arm for limiting the motion
of said arcing contact with respect to said contact arm;
that magnetic button 46 is attracted toward core 48 to ’
exert a counter-clockwise force on arcing contact 18
mally biasing said arcing contact toward ‘an engaged
position with respect to said cooperating contact; said
biasing means including a. high conductivity spring elec
trically connecting said arcing contact to said contact
arm; said spring having a magnetic member contained
therein; said magnetic member being movable toward
about pivot 20 which, along with the biasing force of
the normal biasing spring acting on arcing contact 18,
said arcing contact being electrically insulated from said
contact arm at the pivot point; a biasing means for nor
will counteract the blow-01f force imparted to contact 18.
As seen in the solid line position of FIGURE 3, the
said arcing contact to impart a force to said arcing con
arcing contact 18 will remain in engagement with contact
tact in the same direction as the biasing force of said
31 in which movable contact 14 has established a su?i
spring responsive to current ?ow therethrough.
cient clearance distance from main stationary contact
3. A movable contact arm for a circuit breaker; said
28. After this distance has been reached, the continued
motion of contact arm 10 to its fully disengaged position 60 movable contact arm being movable between an engaged
and disengaged position with respect to a cooperating
shown in the dot-dash view of FIGURE 3 will move
contact; said movable contact arm carrying a main con~
the arcing contact 18 away from contact 31 and against
tact and an arcing contact; said arcing contact being
stop ‘32. which picks-up rearwardly projecting end 30 of
pivotally connected to said contact arm; abutting means
arcing contact 18.
mounted to said movable arm for limiting the motion
A further embodiment of the auxiliary spring sole
of said arcing contact with respect to said contact arm;
noid means of FIGURES 2 and 3 is shown in FIGURE
4 where the auxiliary conducting spring 56 is concentri
cally positioned with respect to the main biasing spring
58 which is similar to biasing spring 34 of FIGURE 1.
In FIGURE 4, the main biasing spring 58 is seated 70
upon an insulated base 60 carried by contact arm it]
said arcing contact being electrically insulated from said
contact arm at the pivot point; a biasing means for nor
mally biasing said arcing contact towards an engaged
position with respect to said cooperating contact; an
auxiliary means including a solenoid Winding connecting
and conductive spring or coil 56 which is electrically
said arcing contact to said contact arm, and a magnetic
connected to arcing contact 18 at end 62 and to movable
contact arm 10 at end 64 is concentrically positioned
member within said solenoid; said magnetic member
being movable toward said arcing contact to impart a
with respect to main spring 58.
As was the case of 75 force to said arcing contact in the same direction as
3,0205%
5
6
the biasing force of said biasing means responsive to
current ?ow through said arcing contact.
said arcing contact being electrically insulated from
4. A movable contact arm for a circuitbreaker; said
movable contact arm being movable between an engaged
and disengaged position with respect to a cooperating
normally biasing said arcing contact towards an engaged
position with respect to said cooperating contact; an
auxiliary means including a solenoid winding connect
contact; said movable contact arm carrying a main con
ing said arcing contact to said contact arm, and a mag
tact and an arcing contact; said arcing contact being
pivotally connected to said contact arm; abutting means
netic member within said solenoid; said magnetic mem
her being movable toward said arcing contact to impart
said contact arm at the pivot point; a biasing means for
mounted to said movable arm for limiting the motion
a force to said arcing contact in the same direction as
of said arcing contact with respect to said contact arm; 10 the biasing force of said biasing means responsive to cur
said arcing contact being electrically insulated from
rent ?ow through said arcing contact; said biasing means
being a spring.
7. A contact for a circuit breaker; said contact being
. said contact arm at the pivot point; a biasing means for
normally biasing said arcing contact towards an engaged
position with respect to said cooperating contact; an auxil
pivotally mounted on a movable contact arm; a biasing
iarry means including a solenoid winding connecting said 15 spring for biasing said contact in a ?rst direction; and
arcing contact to said contact arm, and a magnetic mem
auxiliary means for imparting additionaliorce to said
ber within said solenoid; said magnetic member being
contact to move said contact in said ?rst direction; said
movable toward said arcing contact to impart a force
auxiliary means electrically connecting said contact to
to said arcing contact in the same direction as the biasing
said contact arm and being operable responsive to cur
force of said biasing means responsive to current ?ow 20 rent flow through said movable contact; said auxiliary
operating means including a solenoid means winding
through said arcing contact; said biasing means being a
spring.
1
conducting the current ‘through said contact and a plunger
movable toward engagement with said contact when
5. A movable contact arm for a circuit breaker; said
said solenoid winding is energized.
movable contact arm being movable between an engaged
and disengaged position with respect to a cooperating 25
8. A contact for a circuit breaker; said contact being
contact; said movable contact arm carrying a main con
pivotally mounted on a movable contact arm; a biasing
tact and an arcing contact; said arcing contact being
pivotaily mounted with respect to said contact arm; said
arcing contact being electrically insulated from said
spring for biasing said contact in a ?rst direction; and
auxiliary means for imparting additional force to said
contact arm at the pivot point; 'a biasing means for nor
mally biasing said arcing contact towards an engaged
position with respect to said cooperating contact; said
contact to move said contact in said ?rst direction; said
30 auxiliary means electrically connecting said contact to,
said contact arm and being operable responsive to cur
rent flow through said movable contact; said auxiliary
operating means including a solenoid means winding con
biasing means including a high conductivity spring elec
ducting the current through said contact and a plunger
trically connecting said arcing contact to said contact
arm; said spring having a magnetic member contained 35 movable toward engagement with said contact when said
therein; said magnetic member being movable toward
said arcing contact to impart a force to said arcing con
tact in the same direction as the biasing force of said
spring ', responsive to current ?ow therethrough.
6. A movable contact arm for a circuit breaker; said 40
movable contact arm being movable between an engaged
and disengaged position with respect to a cooperating
contact; said movable contact arm carrying a main con
tact and an arcing contact; said arcing contact being
pivotally mounted with respect to said contact arm; 45
solenoid winding is energized; said biasing spring form
ing said solenoid winding.
7 References Cited in the ?le of this patent
UNITED STATES PATENTS
1,762,604
Ainsworth ____
1,804,628
1,827,430‘
2,186,251
2,761,040
MacNeill __________ __ May 12,
Greenwood __________ __ Oct. 13,
Lindstrom ____________ __ Jan. 9,
Ulrich ______________ __ Aug. 28,
_____ __ June 10, 1930
1931
1931
1940
1956
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