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Патент USA US2354162

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July 18, 1944.
2,354,162
J. WEBER
CIRCUIT BREAKER
Filed March 19, 1942
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ATTORNE
Patented July 18, 1944
"
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2,354,162
UNITED sTATEs` PATENT OFFICE
2,354,162
CIRCUIT BREAKER
Joe Weber, Irwin, Pa., assignor to Westinghouse
Electric & Manufacturing Company, East Pitts
burgh, Pa., a corporation of Pennsylvania
Application March 19, 1942, Serial No. 435,367
21 Claims. (Cl. goo-88)
This invention relates to circuit breakers and,
a circuit breaker with an improved trip device
more particularly, to circuit breakers of the type
which is simple in construction, reliable and ef
which are operated instantaneously on heavy
ficient in operation, and inexpensive to manu
overloads or short circuits and after a time delay
facture.
on persistent overloads of lesser magnitude.
An object of the invention is\to provide a cir
cuit breaker having an improved current re
sponsive trip device wherein a resistance con
nected in series with an electromagnet for trip
ping the breaker is controlled by a thermal ele
ment to control energization of the electromag
net and tripping of the breaker.
~
Another object of. the invention is to provide
a circuit breaker with an improved trip device
wherein a thermal element deñects, when heated
in response to overload currents, to reduce a re
sistan‘ce connected in series with the Winding of
the trip magnet, thereby causing increased ener
The novel features that are considered char
acteristic of the invention are set forth in par
ticular in the appended claims. The invention
itself, however, both as to structure and opera
tion, together with additional objects and ad
10 vantages thereof, will be best understood from
the following description of several embodi
ments thereof when read in conjunction with the
accompanying drawing, in which:
Figure 1 is a vertical sectional view of a cir
cuit breaker embodying the principles of the
invention; and
Figs. 2 and 3 are fragmentary views oi a cir
cuit breaker embodying modiiled forms of the
gization of the magnet to trip the breaker.
invention.
Another object of the invention is to provide 20
The circuit breaker illustrated in Fig. 1, with
a circuit breaker having an improved trip device
the exception of the trip device, is essentially the
wherein the deñection of a thermal element in
same as that disclosed in United States Patent
response to excessive current controls a. variable
No. 1,802,758, issued to H. D. Dorfman on April
regulator or a resistance tol increase the energiza
28, 1931, and assigned to the assignee of the ln
tion of a trip electromagnet and eil'ect tripping 25 stant invention, and only a brief description
oi the breaker.
of the structure of the circuit breaker will be
Another object of the invention is to provide
given herein. For the specific details of con
an improved circuit breaker wherein a trip mag
struction, reference may be had to the patent
net is energized under the control of a variable
referred to.
i
regulator or a resistance, which is varied by a bi 30
The circuit breaker comprises, generally, a
metal elementin accordance with the magnitude
base 1 and a cover 9 of molded insulating ma
and duration of the overload current.
terial, end terminals Il, a stationary contact I3,
Another object of the invention is to provide
a movable contact l5, operating mechanism in
a circuit breaker in accordance with the preced
dicated generally at il, a current-responsive trip
ing paragraphs wherein means is provided for
device indicated at i9, and an arc extinguish
adjustably determining the initial resistance of
the resistor to vary the operating point of the
er 2|.
The movablecontact I5'is secured to a re
silient contact arm 21 which, in turn, is secured
Another object oi' the invention is to provide a
by suitable means to a channel-shaped frame 29
circuit breaker with an improved trip device 40 pivotally supported by means of a pivot pin 30
trip magnet.
wherein a regulator or a resistance connected in
series with a trip magnet is controlled by a ther- v
on a, U-shaped main frame 3i.
mal element to effect tripping of the breaker
U-shaped operating lever 33 having an operating
handle 35 secured to the outer end thereof and
after a time delay on overloads below a prede
The operating mechanism
I'l comprises a
termined value, and in which the magnet is ef 45 projecting through an opening 36 in the cover
fective to trip the breaker instantaneously on
9, a cradle 31, a toggle comprising a pair of
overloads above the predetermined value.
toggle links 39 and 4I, and a pair of overcenter
Another object of the invention is the pro
springs 43 (only one of which is shown). The'
vision of a circuit breaker with an improved trip
operating lever is pivotally mounted on pivot
device embodying a thermally responsive ele- 50
pins 34 supported in the sides of the frame 3|,
ment heated in response to overload current of
and the cradle 3l is pivoted on a pin 38 also
the circuit, and having means for varying the
supported in the frame 3|. One end of the
speed of response of the device in accordance
toggle link 39 is pivotally connected to the cradle
with the magnitude of the overload current.
3l by a pin 40, and the toggle link Il is pivotally
Another object oi the invention is to provide
connected to the free end of the channel-shaped
2
2,354,162
member 2G by means of a pin 42.
The toggle
linlrs 39 and 4| are pivotally connected together
by a knee pivot pin 44. The overcenter springs
43 are tensioned between the knee pin 44 of the
toggle 39-4i and the outer end of the operat
ing lever 33. The cradle 31 is provided with a
latch end 45 with which a pivoted latch member '
conductor 93, and the conductor Il is connected
to the channel frame 29 by means of a flexible
shunt conductor 95.
'
The circuit of the breaker extends from the
left-hand terminal || through the conductor 2l,
the resistance shunt conductor 3|, the conduc
tor 93, flexible shunt conductor B5, channel mem
ber 29, resilient contact arm 21, movable contact
lil is adapted to cooperate to releasably restrain
I5, the stationary contact I3, the conductor 25
the cradle 31 in the position shown. The operat
ing member 33 is provided with an extension 10 to the other terminal ||. The bimetal element
B9, the winding 63 of the magnet 6| and the
which is adapted to cooperate with the cradle
carbon pile 61 are electrically connected in se
in order to relatch the cradle by manual move
ries relation in a shunt circuit as follows: Prom
ment of the handle 35 to the “oil” position after
the terminal || through the conductor 20, angie
the breaker has been tripped open.
When the latch member 41 is operated by the 15 bracket 1|, bimetallic element 59, a flexible wire
51, winding 63 of the electromagnet 9|, a wire
trip device i in a manner to be presentLy de
89, through the carbon pile 51 and a wire 5| to
scribed, the cradle 31 is released and rotated in
the conductor 83, thus completing a shunt circuit
a clockwise direction by the overcenter springs
43. During this rotation, the line of action of
the springs 43 changes to cause collapse of ‘the 20
in parallel with the shunt member 3|.
When normal rated current flows through the
circuit of the breaker, the resistance of the car
toggle SE--âi and opening oi the contacts |5-|3.
bon pile 61 is of such value that current llow
‘Before the contacts may be closed, it is neces
through the bimetallic element 33 and the mag
sary to relatch the cradle 31 with the latch mem
net winding 63 is negligible, and, therefore,.i5 in
ber 4l. This is effected by moving the operating
handle ¿i5 in a counterclockwlse direction, during 25 sufficient to energize the winding 53 to cause
operation of the latch member 41. Upon the
which movement the extension 49 of the operat
occurrence of a persistent overload current, the
ing lever 33 engages and rotates the cradle 31
resistance of the shunt conductor 8| forces an
in the same direction to reengage the latch por
increased flow of current through the bimetni
tion 45 of the cradle with the latch 59. The
contacts can now be closed by moving the handle 30 59, the winding of the electromagnet 6| and the
.t5 and the operating lever 33 to the extreme
right-band position. This movement changes the
resistance 61. This results in heating the bimetal
an amount determined by the value and duration
of the overload current, and causes the bimetal to
line of action of the overcenter spring so as to
deflect in a. direction to increase the compression
straighten the toggle 39-4l and thus effect clos
ing ci" the contacts.
35 of the carbon pile 61. The resistance of the
carbon pile is thereby lowered, resulting in an in
'.ll‘he breaker may be opened manually by mov
creased flow of current through the winding 5l
ing the handle 35 toward the left. During this
and the bimetal element 69. The increase in the
movement, the line of action of the overcenter
value of current flowing through the bimetal ele
springs 43 is moved to the left oi' the pivot pin
it
causing the springs to exert a force on the 40 ment due to the decrease in resistance of the
carbon pile 61 causes the bimetal to be heated
e of the toggle 39-4i in a direction to cause
collapse of the toggle, which results in move
ment of the movable contact |5 to open position.
The contact-s are closed in the previously de
at an increased rate, thereby producing a cumu
pivotally mounted on a pivot 5| supported on
ears 53 (only one being shown) formed on the
decreases at an accelerated rate as the magni
lative effect to increase the rate and extent of
deflection of the bimetal element. Thus the time
45 delay action of the trip device is less than the
scribed manner.
«
ordinary thermal trip device, and the time delay
The trip device I9 includes the latch member
tude of the overload current increases. When
the current flow through the electromagnet
support member 55. A spring 51 biases the latch
member in latching direction. On the free end 50 reaches a predetermined magnitude, the electro
magnet attracts the armature 60 and causes the
of the latch member 41 is mounted an armature
operating mechanism to open the contacts in the
50 adapted to be attracted by an electromagnet
previously described manner..
5i mounted on the support bracket 55. The elec
By rotating the adjusting screw 15. the initial
troniagnet comprises a winding 53 and a core
and is adapted to be energized in 55 pressure on the carbon pile 61 may be increased
or decreased, thus decreasing or increasing the
initial resistance. This provides a convenient
means for varying the operating point of the trip
an insulating button 91 is a variable regulator
device. Upon the occurrence of overloads above
oi' any suitable type, such as a carbon pile 61,
e. bimetallic member 69 is supported on an an 60 a predetermined value or short-circuits, the ex
cessive current energizes the magnet 6| suf
guiar bracket li secured to the conductor 20 by
ficiently to cause instantaneous operation o! the
means of a screw 13, and extends outwardly there
trip member 41 to release the operating mecha
from adjacent one end of the resistance 61. An
nism. Obviously, by mounting the carbon pile
adjusting screw 15 having an insulating button
"Vl mounted on one end thereof bearing against 65 51 on the support 55 a greater or lesser distance
from the base 1, the change in pressure on the
the end of the carbon pile is locked in place on
carbon pile for a given deflection of the bimetal
the bimetal element 69 by means of a lock nut 19.
element may be varied.
The purpose oi the screw 15 is to communicate
According to the modification of the invention
the deflecting movement of the bimetallic mem
shown in Fig. 2, the bimetai element 69 may be
ber @El to the carbon pile 51 and also to provide
provided with an auxiliary armature member 93
a convenient means for adjusting the initial com
securely mounted on the bimetal adjacentl the
pression of the carbon pile. The conductor 20,
core member 65. The purpose of the auxiliary
which is formed as an extension of the terminal
armature 93 is to provide for quicker tripping of
il, is connected by means of a shunt conductor
of predetermined electrical resistance to the 75 the breaker for a given amount of heating of the
me' ber
response to tbe current of the circuit. Also
mounted on the support bracket 55 by means of
9,854,109
bimetal on intermediate overload currents be
low the previously mentioned predetermined
value. When the bimetal element is heated in
response to an overload current, it defiects to
ward the right and simultaneously increases the
pressure on the carbon pile 61 and at the same
time moves the armature 93 closer to the core
3
response to overload currents for varying the re
sistance of said resistor in accordance with the
magnitude and duration o! the overload current
to vary the energization of the electromagnet.
3. A circuit breaker comprising relatively mov
able contacts, operating mechanism for said con
tacts, an electromagnet operable when energized
oi' the magnet. This causes the electromagnet
a predetermined amount to cause opening of
to exert a stronger pull on the armature 93 which
the contacts, a variable resistor for controlling
tends to still further deiìect the bimetal and 10 the
energization of said electromagnet, and a
thereby further decrease the resistance of the
bimetallic element operable in response to over~
carbon pile. The rate of heating of the bimetal
load currents to cause the resistor to increase the
element is increased due to the decrease in re
sistance of the carbon pile and the increased
pull of the magnet on the armature 93 due to
energization of'the electromagnet and thereby
eil'ect opening of the contacts.
4. A circuit breaker comprising relatively mov
able
contacts, operating mechanism for said con
and the decrease in air gap between the arma
tacts, a trip device comprising an electromagnet
ture 83 and core 65 produces cumulative effects
operable when energized by overload currents
all tending to decrease the time delay action of
above a predetermined value to cause in
the device in accordance with the magnitude 20
stantaneous opening of the contacts, a variable
oi' the current. The result is to increase the iiow
resistor connected in the circuit of the electro
of current through the winding 63 and to `in
magnet for controlling the energization ci said
crease the magnetic flux, and thus eiïect quicker
magnet, and a bimetal element operable when
tripping of the breaker for a given value of over
heated by overload currents below said prede
load current than in the case of the original
25 termined value to cause the resistor to increase
embodiment.
the energization of the electromagnet in accord
According to the modiñcation of the invention
ance with the magnitude and duration of the
illustrated in Fig. 3, the magnet winding 63 and
overload current.
the carbon pile 61 are electrically connected in
5. A circuit breaker comprising relatively mov
the increased current ñow through its winding
parallel, and both are connected in series with 30
able contacts, operating mechanism for said con
the bimetal element 89 which is disposed to de
tacts, a trip device comprising electroresponsive
nect, when heated, away from the carbon pile.
means operable when energized a predetermined
Thus, under normal circuit conditions, the pres
amount to cause opening of the contacts, a
sure exerted on the carbon pile by the bimetal
variable regulator for controlling the energiza
element is at its maximum, and the resistance 35 tion of the electroresponsive means, and ther
of the carbon pile is at its minimum, thereby
mally responsive means operable in response to
limiting the value of current flowing through the
overload currents for actuating the regulator
winding 63. As the bimetal 69 is heated and de
in accordance with the magnitude and dura
iiects away from the carbon pile 61, the pressure
tion of the overload current.
thereon is reduced, thus increasing the resistance 40
6. A circuit breaker comprising relatively mov
and causing an increased flow of current through
able
contacts, operating mechanism therefor,
the magnet winding 63. When the magnitude
electroresponsive means operable when energized
of the current flowing through the electromagnet
a predetermined amount to cause opening of
reaches or exceeds a predetermined value, the
the contacts, a variable regulator for controlling
electromagnet efl'ects tripping of the breaker in 45 the
energization of the electroresponsive means,
the previously described manner.
thermally responsive means operable when
Having described several embodiments of the
heated in rsponse to overload currents to actuate
invention in accordance with the patent statutes,
the regulator to increase the energization of the
it is to be understood that various changes and
electroresponsive means an amount determined
modifications may be made therein without de 50 by the magnitude and duration of the overload
parting from‘some of the essential features of
current, and means for adjusting the regulator
the invention. It is, therefore, desired that the
to vary the operating point of the electrorespon
language of the appended claims be given as rea
sonably broad interpretation as the prior art per
mits.
I claim as my invention:
»
sive means.
7. A circuit breaker comprising relatively mov
55 able contacts, operating mechanism for said con
tacts. a trip device comprising an electromagnet
1, A circuit breaker comprising an operating
operable when energized a predetermined amount
mechanism for operating the breaker, a trip de
to cause opening of said contacts, a variable re
vice comprising an electromagnet operable to
sistor for controlling the energization of the
cause operation of the breaker, a resistor elec 60
electromagnet,
a bimetallic member operable
trically connected in series with said electro
when heated in response to overload currents for
magnet, and a current-responsive member con
actuating the resistor to cause increased ener
nected in series relation with said electromagnet
gization
of the electromagnet ln accordance with
and said resistor, said current-responsive mem
the magnitude and duration of the overload cur
ber being operable in response to certain circuit 65
rent, and means for adjusting the resistor to
conditions to decrease the resistance of the re
vary the initial resistance thereoi‘.
sistor and cause the electromagnet to trip the
8. A circuit breaker comprising relatively mov
breaker.
able contacts, operating mechanism for said con
2. A circuit breaker comprising an operating
mechanism for causing automatic operation of 70 tacts„a trip device comprising an electromagnet
operable when energized to cause opening of the
the breaker, a trip device comprising an electro
contacts,
a variable resistor for controlling the
magnet operable to cause operation of said
energization of said electromagnet, auxiliary
mechanism, a variable resistor for controlling
magnetic means operable to vary the magnetic
the energization of said electromagnet, and ther
mally responsive means operable when heated in 75 reluctance of said electromagnet, and a bimetal
lic element operable when heated in response
4
2,354,162
to overload currents for simultaneously actuat
ing the resistor' to eiïect increased energization
oi the electromagnet and for actuating the
auxiliary magnetic means to reduce the magnetic
reluctance.
9. A circuit breaker comprising operating
mechanism for causing automatic Operation of
the breaker, a trip device comprising an electro
energized a predetermined amount to operate the
armature, a. variable resistor comprising a car
bon pile operable to vary the energization of the
magnet, an auxiliary armature operable to vary
the reluctance of the magnet, and a bimetallic
element operable when heated in response to
current to simultaneously operate the carbon
pile and the auxiliary armature to simultaneously
increase the energization of the electromagnet
magnet operable to cause said mechanism to
operate the breaker, a variable resistor for con 10 and reduce the magnetic reluctance.
15. A circuit breaker comprising relatively
trolling the energization of said electromagnet,
movable contacts, operating mechanism there
and a bimetallic element operable when heated
in response to overload currents to increase the
for, an electromagnet including an armature
resist-ance of said resistor and cause increased
operable to cause opening of said contacts, a
energization of the electromagnet.
variable resistor for controlling the energization
l0. A circuit breaker comprising relatively
movable contacts, operating mechanism for said
contacts, a trip device comprising an electro
of said electromagnet, an auxiliary amature
operable to vary the magnetic air gap of the elec
tromagnet, and a bimetallic element operable
when heated in response to current to actuate
magnet operable when energized a predeter
mined arnount to cause opening of said contacts, 20 the variable resistor and the auxiliary armature
to simultaneously increase the energization o!
a variable resistor for controlling the energiza
the electromagnet and reduce the magnetic air
tion of said electromagnet, a bimetallic element
operatively associated with said resistor and
88D
16. A circuit breaker comprising relatively
operable in response to overload currents to in
crease the resistance of said resistor to thereby 25 movable contacts, operating mechanism therefor,
a trip device operable to cause opening of the
increase the energization of the electromagnet,
contacts, said trip device comprising a bimetal
and adjustable means for adjustably determin
element heated in response to the current of the
ing the initial resistance of said resistor to vary
circuit and operable to cause operation of the
the operating point of the electromagnet.
ll. A circuit breaker comprising relatively 30 trip device, a variable resistance connected in
series relation with said bimetal element in the
movable contacts, operating mechanism biased
circuit controlled by the breaker, said bimetal
to cause opening of said contacts, latch means
for restraining said loperating mechanism and
element deilecting when heated to reduce the
resistance of the variable resistance thereby in
operable to cause opening of said contacts, an
electromagnet operable when energized a pre 35 creasing the heating of the bimetal element.
17. A circuit breaker comprising an operating
determined amount i‘or operating said latch
mechanism for operating the breaker, a trip de
means, a variable resistor for controlling the
amount oi energization of said electromagnet,
vice comprising an electromagnet operable to
cause operation of the breaker,_ a variable re
in response to overload currents to decrease the 40 sistance electrically connected in the energizing
circuit of said electromagnet, a bimetal element
resistance of the resistor thereby increasing the
and a bimetallic element operable when heated
energization ci’ the electromagnet.
at all times connected in series relation with said
l2. A circuit breaker comprising relatively
variable resistance and heated in response to
movable contacts, operating mechanism for said
the current of the circuit of the electromagnet,
contacts, an armature operable to cause opening 45 and means including said bimetal element for
varying the resistance of said variable resistance.
or" said contacts, an electromagnet operable when
18. A circuit breaker comprising relatively
energized a predetermined amount for operat
movable contacts, operating mechanism for said
ing said armature, a variable resistor comprising
contacts, a trip device comprising an electromag
a carbon pile for controlling the amount of ener
gization of said electromagnet, a bimetallic ele 50 net operable when energized by overload currents
above a predetermined value to cause instan
ment operable when heated in response to cur
taneous opening of the contacts, a variable re
rent for actuating said carbon pile to reduce the
sistor connected in the circuit of the electromag
resistance thereof to thereby increase the ener
net for controlling energization of said magnet.
gization of the electromagnet and cause said
electromagnet to operate the armature.
55 and a bimetal element connected in series with
a parallel connection of said variable resistor
13. A circuit breaker comprising relatively
and the electromagnet, said bimetal element be
movable contacts, operating mechanism for said
ing heated in response to the current in the cir
contacts, an armature operable to cause opening
cuits of the electromagnet and said variable re
of the contacts, an electromagnet operable when
energized a predetermined amount to operate 60 sistor, said element being deiiectable in response
to predetermined heating of said element to op
said armature, a variable resistor comprising a
erate the resistor and vary the resistance of said
carbon pile for varying the energization of said
variable resistor.
electromagnet, a bimetallic element operable
19. A circuit breaker comprising relatively
when heated in response to current to reduce
the resistanceoi said carbon pile to thereby in
crease the energization of the electromagnet and
cause said electrcmagnet to operate the arma
ture. and adjustable means i'or determining the
initial resistance of the carbon pile to vary the
operating point of the electromagnet.
i4. A circuit breaker comprising relatively
movable contacts, operating mechanism for said
65 movable contacts, operating mechanism for said
contacts, a trip device including an electromag
net having an armature operable to cause open
ing of the contacts, a variable resistance for con
trolling the energization of said electromagnet, a
bimetal element deñecting when heated in re
sponse to overload currents in a direction to
actuate the variable resistance to thereby cause
increased energization of the electromagnet, and
an auxiliary armature movable toward the elec
tacts, said electromagnet being operable when 75 tromagnet upon deflection of the bimetal ele
contacts. an electromagnet including a movable
armature operable to cause opening of the con
ment, said auxiliary armature exerting a force
on the bimetal element tending to deñect said
element in the same direction as the heating
action.
'
20. A circuit breaker comprising relatively
movable contacts, operating mechanism for said
contacts, an electromagnet including a movable
operate the carbon pile and to move the auxiliary
armature closer to the electromagnet to thereby
effect increased energization of said magnet.
21, A circuit breaker comprising relatively
movable contacts, operating mechanism therefor,
an electromagnet includinz an armature oper
able to cause opening of said contacts, a variable
resistor for controlling the energization of said
tacts, said electromagnet being operable when
magnet, a bimetal element operable when heated
energized a predetermined amount to operate the l0
in response to current to actuate the variable re
amature, a variable resistor comprising a car
sistor to cause increased energization of the elec~
bon pile operable to vary the energization of the
amature operable to cause opening of the con
tromagnet, and an auxiliary armature'movable
Yby the bimetal element and operable by the elec
to effect increased energization of the electro
tromagnet to eñ'ect additional increase in the
magnet, and a bimetal element operable when 15 energization of said magnet,
heated ln response to current to simultaneously
electromagnety an auxiliary armature operable
JOE WEBER.
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