Oct. l, 1929.
P. THOMAS
1,730,254
connor. srsru
Filed lay 3, 1928
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INVENTOR
Phillips Thomas
BY
ATTORNEY
Patented Oct. l, 1929
1,730,254 ._
vum'rrso STATES-PATENT ori-'ica
PHILLIPS THOIAS, OF EDGEWOOD, PENNSYLVANIA, ASSIGNOB 'I‘O WESTINGEOUIE
ELECTRIC à HANUFACTUBING COMPANY, A CORPORATION OF PENNSYLVANIA
CONTROL SYSTEM
Application ßled Nay 3, 1928. Serial No. 274,762.
This invention pertains to electrical -con
tion circuit 12 and the control system indi-`
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trol systems and has for its principal object cated generall at 13.
the provision of a control system which
This contro system consists of two of the
shall be capable of controlling considerable above-mentioned iron-core reactors 14 and
amounts of alternatin -current ener
in ac
15. _ The reactor 14 is provided with an alter
cordance with variatlons in a smal direct natlng-current winding 16 and a direct-cur~ 55
current.
rent winding 17. The alternating-current
A further object of my invention is to pro
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winding 16 is evenly divided between the two
vide an electrical system of control of the type outside arms of the magnetic circuit so that
described which is adaptable for manual or the net alternating flux in the center arm is
automatic operation.
always zero. The direct-current winding 17
A further object of this invention is to may be energized from any suitable control '
provide a control system characterized by sim source, as an example of which I have illus
plicity and cheapness of construction and trated a thermo-couple 18.
15 reliability in operation. ,
Connected in parallel with the alternatin
In accordance with my invention I employ current winding 16 of the reactor 13 is a ful
l a pluralit of saturable iron-core reactors of wave rectifier 19 which ma be of any suitable
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the ty e escribed in my copending applica-l type but is, preferably, o the copper-oxide
tion, erial No. 221,490, filed Septem er 23, disc type.
1927 for Synchronizing relay systems. These The reactor 15, like the reactor 14, is pro
reactors are provided with alternating-cur vided with an alternating-current winding 70
rent windings similar to those of the usual 20 and a direct-current winding 21. The al
core-type distribution transformer and, in ternating-current winding 20 and the load
addition, with a direct-current winding the device 11 are connected in series, and in series
function of which is to saturate the reactor with the reactor 14 and the rectifier 19 in
core and thereby reduce the net alternating parallel, across the distribution circuit 12.
flux in the 'core so that the voltage induced vAlthough the load device 11 may be of
in the alternating-current winding is corre any type whatever, my invention is particu
spondingly reduced and the effective reac larly suited for the control of such load de
tance of the reactor itself is likewise reduced. vices as electric furnaces or other heating
The operation of the reactors above de
' A scribed follows from the well known principle
devices, and, according to one modification
of my invention, it is possible to maintain
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that the super osition of a uni-directional automatically a constant temperature at any
flux upon an a ternating flux in a magnetic desired point.
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circuit has the eíit‘ect of reducing the net alter
nating flux in the ma
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etic circuit.
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The method of operation of the system
shown 'in Fig. 1 will now be described.
Further objects o my invention will be
As is apparent from Fig. 1, the alternat
come apparent in the course of the following ing-current windings 16 and 20 of reactors
description thereof and the features which 14 and 15 are connected in series across dis
I consider novel will be particularly pointed tribution circuit 12, the load device 11 being
out in the appended claims.
connected in series with the reactors 14 and
A com lete understanding of my invention 15. When the direct-current windings 17
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may be o tained from a consideration of the and 21 of the reactors 14 and 15 are de
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accompanying drawings, in which
energized the reactance of the alternating
Figs. 1, 2 and 3 illustrate, schematically, current windings 16 and 20 of the reactors
various modifications of the control system of `14 and 15 attains its maximum value and the
my invention.
voltage across the circuit 12 is divided be
Referring particularly to Fig. 1, a source tween t-he reactors 14 and 15 and the load
of alternating current 10 is adapted to suppl device 11.
energy to a load devicev 11 over the distri ~
Obviously, the same voltage that exists
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across the alternating-current winding 16 of the reactor 35 is connected across the cir
cuit 32 in series with the load device 3l.
The reactors 34 and 35 are provided with
direct-current windings 39 and 40. The
winding 39 is connected to any suitable source
of energy such as a battery 41, in series with 70
a control device such as the rheostat 42. The
y As lon as the Winding 21 is de-energized, direct-current winding 40 of the reactor 35 is
as a resu t of an open circuit, for example, connected to the direct-current terminals of
of the reactor 14 appears across the alter
nating-current terminals of the rectifier 19
and a direct current, proportional thereto,
flows from the remaining terminals of the
rectifier to the direct-'current winding 21 of
the reactor 15.<
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15
the voltage across the alternating-current the rectifier 37. The operation of the system
winding 20 of the reactor l5 is large com illustrated in Fig. 2 is similar to that shown
pared to that across the terminals of the load in Fig. 1 except that the reactor 35 controls
device l1 which is, therefore, energized only the current through the load device 31 while
the reactor 15 controls the voltage across the
to a slight degree.
The energization of the direct-current load device 11. An increase in the energiza
winding 21 of the reactor 15, however, tion of the winding 39 of the reactor 34 satu
saturates the core of the reactor and, in ac
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rates the core thereof and reduces the voltage
cordance with the foregoing explanation, re across the winding 36. An increased voltage
duces the net alternating flux in the reactor is thus impressed upon the alternating-cur
and, consequently, reduces the voltage rent terminals of the rectifier 37 so that the
l2c core,
across the alternating-current Winding 20 energization of the direct-current winding 40
and increases the voltage across the load of the reactor 35 is increased. This results
device 11 in series therewith. The energiza in a corresponding decrease in the voltage
tion of the load/device 11 is, of course, in across the winding 38 of the reactor 35 and
25 creased in proportion to the increase in the an increase in the voltage across the load de
vice 31 or, in other words, an increase in the
voltage thereacross.
y'
If it be now assumed that'the temper current therethrough.
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Conversely, a decrease in the energization
ature of Vthe thermo-couple 18 is increased,
the direct-current winding 17 of the reactor of the winding 39 will cause the voltage in
30
14 will be correspondingly energized. The duced in the winding 36 to increase so that a
voltage across the alternating-current wind smaller ortion of the line voltage is effective
ing 16 will thereupon be reduced and like across tlie rectifier 37. A reduced current
wise the voltage across the rectifier 19 so thereby energizes the Winding 40 of the reac
that, as a result- of the increase in the tem
35
40
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tor 35 so that the voltage across the alternat
perature of the thermo-couple 18, a decrease ing-current winding 38 thereof is increased
in the energization of the Winding 21 of and the voltage drop across the load device
the reactor 15 occurs. As already explained, 31 is correspondingly decreased.
It will _be obvious that, if the impedance
the reduction in the energization of the wind
ing 21 causes an increase in the voltage in 42 is the exploring coil of a resistance ther
duced in the winding 20, and a decrease in mometer, the energization of the device 31
the voltage impressed upon the load device may be automatically controlled in accord-ance with the temperature at any given point.
11.
1f the device 31 is an electric furnace or
It is thus apparent that variations in the
temperature of the thermo-couple 18 will be other heating apparatus, and if the exploring
eñ'ective to cause corresponding changes in coil 42 is placed in close proximity thereto,
the following operation will result: An in
the energization of the device 11.
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The reactor 15 should bë‘dcsigned so that crease in the temperature of the device 31 will
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its impedance will be high when unsaturated likewise increase the resistance of the explor
and low when saturated, as compared with ing coil 42 and decrease the energization of
the impedance of the load device 11. This the winding 39. As already explained, this
relation between the load impedance andthe decrease in the energization of the winding
variable controlling impedance makes pos 39 causes an increase in the voltage across
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sible a continuous control of the former over the winding 36 and a decrease in the voltage
across the rectifier 37 with a consequent de
a wide range.
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60
65
Referring now to Fig. 2, which is a dia->
gram illustrating a modification of my in
vention, the alternating-current source 30 is
adapted to supply a load device 31 over the
distribution circuit 32 and the control sys
tem 33.
crease in the energization of the winding 40.
This last variation causes the voltage across
the winding 38 to increase and that across
thedevice 31 to decrease so that its energiza
tion is decreased and its temperature reduced.
Should the temperature of the heating de
The control system 33 comprises a plurality vice 31 be .reduced beyond a predetermined
of reactors 34 and 35. The alternating-cur value, the energization of the winding 39
rent winding 36 of the reactor 34 is connected would be increased as a result of the decrease
across the circuit 32 in series with the rectifier in the resistance of the‘eoil 42. Thus the
37 while the alternating-current winding 38 voltage across the winding 36 will be de
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creased and that across the rectifier mcreased including thewinding 60, causes the voltage
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causing an increase in the energization of across the windin 57 and the rectifier 63 to
the winding 40 and a 'decrease in the voltage' be decreased an the energization of the
across the winding 38 followed by a cor winding 61 is, therefore, correspondingly de
respondin increasepin the volta e on the de creased. The resulting increase in the volt
vice 31. Ihe temperature of t e device 31 age across the winding 58 and the rectifier 64 70
is, therefore, increased to the aforo-mentioned further the effect of the increased energiza
predetermined value.
tion of the winding 60. The winding 62 is
The constant temperature maintained by also subject to an increased voltage and the
the system of my invention, as explained voltage across the winding 59 decreases and
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above, obviously epends upon the design of that across the load device 51 increases.
the reactors 34 and 35 and the extent to which
It is apparent from the foregoing descrip
the ener ization of the windings 39 and 40 tion that I have provided means for varying
is varie vby the changes in the temperature thedivision of the voltage across a distribu
of the explorin coil 42.
A third modi cation of my control system
is illustrated in Fig. 3 wherein'an alternat
ing-current source 50 supplies energy to a
load device 51 through a dlstributing circuit
52 and a control system 53.
tion circuit between a load device and a con
trol impedance. As previously stated, this
control may be effected manually or auto
matically and may be utilized in a wide
variety of applications.
Among the particular advantages of the
The control system 53 comprises three re >system of -my invention is the fact that the
actors 54, 55 and 56 having alternating-cur
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devices.
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As an example of the effectiveness of my
connected across the circuit 52 in series with system, a practical embodiment thereof dis
the load device 51.
closed results as follows: A variation in the
The rectifier 63 supplies direct current to energization of the Winding 39 of Fig. 2 from
the Winding 61 of the reactor 65 while the zero to .5 of a watt caused a change in the
rectifier 64 energizes the direct-current Wind power supplied to the load device from 200 to
ings 60 and 62 of the reactors 54 and 56.
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v control is effected without the use of any lmov
rent Windin s 57, 58 and 59 and the direct ing parts. The reactors and their windings
current-Win ings 60, 61 and 62. The wind are entirel static and no circuits need be
ings 57 and 58 are connected in series across made nor ¿roken to obtain a positive, con
the circuit 52 and rectifiers 63 and 64 are con tinuous control of the energization of the load
nected in parallel vwith the windings respec
tively. The winding 59 of the reactor 56 is
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,
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800 watts. Thus a variation of .5 of a watt in
A rheostat 65 controls the energization of the energization of the winding 39 produced
the winding 60.
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a change of 600 watts in the energization of
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The operation of the system shown in Fig. the load device 31. The amplification factor,
3 is similar to that of those modifications al
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therefore, was 600/.5 or 1200. These figures
ready described, but in the system of Fig. 3, show that a large change in the energization
a slight change in_the setting of the _rhcostat of the load device may be effected by com
65 causes a ‘greater change in the energization paratively small change in the energization
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>of the load device 51 than in the systems of of the direct-current Winding of the control- Figs. 1 and-2 because of the regenerative or ling reactor.
' amplifying effect made possible by the use of
Although I _have described but three modi
the third reactor.
fications of the system embodying my inven
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An increase in the resistance of the circuit tion, and mentioned only one specific applica
including the Winding 60 of the reactor 54, tion thereof, it is not my intention that the
which is energized by the rectifier 64 connect scope of the invention be limited to the modi
ed across the winding 58 of the reactor 55, fications herein disclosed except as necessi
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Winding 57 and the rectifier 63. The in
creased energization of the winding 61, re
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50 will cause an increase in the voltage across the
tated by the appended claims.
I claim as my invention:
1. A control system comprising a plurality
sulting therefrom, decreases the voltage in of iron-core reactors having alternating-cur
duced in the winding 58 which is impressed rent windings and direct-current windings,
u on the rectifier 64. Thus the energization means for controlling the energization of the
of) the winding 60 is still further decreased direct-current Winding of one of said reactors,
60
65
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and the effect introduced by the increase in and means connected to the alternating-cur
the resistance in the circuit of the winding rent winding of said reactor for energizing
60 is, therefore, magnified. The reduction in the direct-current winding of another of said
the voltage across the rectifier 64 effects a
. decrease in the energization of the winding
62 of the reactor 66 so that the voltage across
the winding 59 is increased and that across
the load device 5l is decreased.
reactors, and a load device connected to the
alternating-current Winding of said last-men
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tioned reactor.
2. An electrical system of control compris
ing a plurality of iron-core reactors having
A decrease in the resistance of the circuit, alternating-current and direct-current windî
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ings, means for energizing the direct-current
winding of one of said reactors, a rectifier
connected to the alternating-current winding
of said reactor for energizlng the direct-cur
rent winding of another of said reactors, and
a load device connected to the alternating
current winding of said last-mentioned re
actor.
3. A ower-amplifying system comprising
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a. plura ity of iron-core reactors having di
rect-current and alternating-current wind
ings, the direct-current winding of one of
sald reactors being connected to an input cir
cuit, the alternating-current winding of an
other of said reactors bein connected to an
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output circuit, and means or energizing the
direct-current winding of the last-mentioned
reactor in accordance with the voltage in
duced in the alternating-current winding of
said first-mentioned reactor, whereby the
variations in the power supplied to said in
put circuit are amplified in said output cir
cuit.
In testimony whereof, I have hereunto sub
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scribed my name this 24th day of April, 1928.
PHILLIPS THOMAS.