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Патент USA US2128056

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Aug. 23, 1938.
D. SANTINI ET AL
I 2’ 1
REGULATING APPARATUS
Filed \July 31, 1936
3 sheets-sneak}
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_ Dani/o
INVENTOR‘S
Saar/m and
JEIWIBW Ha. I
499
Patented Aug. 23, 1938» _
2,128,056 -
UNITED STATES
PATENT . OFFICE
‘2,128,058
REGULATING APPARATUS
Danilo, Santini, Chicago, 111., and Kenneth Mar
.tin White, Tenaiiy, N. 1., assignors to West
lnghouse Electric Elevator Company, Chicago,
- ' Ill., a corporation of Illinois
Application July .‘tl, 1936, Serial No. 93,618
17 Claims.
This application is a continuation-in-part of
our copending application, Serial'No. 38,770, ?led
August 31, 1935 and‘assigned to the Westing
house Electric Elevator Company. The present
5 application discloses an invention, relating to
regulating apparatus, which has been divided
from the parent ‘application, and also discloses
a novel relationship of resistances‘in a control
system of the type disclosed in-the above-men
10 tioned parent application. '
Our invention relates to regulating apparatus‘
and particularly to such apparatus for regulating
a translating device or machine so that an oper
ating characteristic, such as speed, voltage or
15
torque, is independently controlled in accordance
with a plurality of separate regulating variables.
Although the invention, ‘in the broader aspects, is
applicable to many forms of‘ apparatus, it will be
(Cl. 171-119)
gized from a generator which may be provided
with a series field winding to compensate for the
IR drop in its armature circuit, in the armature
circuit of the motor, and in the leads intercon
necting the armatures. The generator is pro
vided with a separately excited main ?eld wind
ing, the current through which is arranged to be
controlled and reversed in order to operate the
motor and the load attached thereto, for example
the elevator car, at various speeds in either direc 10
tion of travel.
-
‘
The excitation of the main ?eld winding of
the generator may be controlled by means of a
rheostat or the combination of various resistors
and suitable control'devices for inserting various 15
steps of resistance in circuit with the main ?eld
winding. For each step of the controller which‘
described particularly in connection with a motor
alters the current ?owing throughv the main ?eld
ance with two regulating variables, one such reg
plating variable being motor load, and the other
regulating variable being controller position or
introduces undesirable operating conditions in‘
winding of the generator there is a particular
20 control system of the variable voltage type, in
speed of operation of the motor which is desired.
which the motor speed is controlled in accord- ' Any departure in speed from this desired value 20
2 ‘controller setting. In such a system, regulation
of the motor speed involves regulation of the
voltage ‘of the generator associated therewith, so
that the application of the invention for the con
trol of generator voltage generally will be ob
30
vious.
-
v
In the described embodiment of the invention,
the functioning. of the system.
If it were possible to maintain all of the con
ditions in a control system of the Ward-Leonard ‘
‘type absolutely constant, it would then be pos
25
sible to obtain an exact relationship between the
speed of the motor and the setting of the con
troller which
regulates the ?ow of current >
through the main ?eld winding of ‘the generator.
ourregulating apparatus operates to regulate the
Due to the physical constants and characteris
independent .of motor load, and also allows the '
pensating system of some type. This is particu
larly true when the Ward-Leonard control system
isemployed to control the movement of an ele
so~
, tics of the system, however, it is not possible to '
speed of the motor so as ‘to maintain the latter achieve such a result without the use of a com
35 regulated motor speed to be ?xed at any of a
number of values determined by controller posi
tion or setting.’
'
vator car in a, hatchway. In such case, additional
variables enter into the functioning of the sys
tem which make it dif?cult to maintain the speed
of the elevator car under all conditions at prede 40
termined values corresponding to the various set
also in accordance with controller position or set- ' tings of the controller for the main ?eld winding
ting. However, in all such systems of which we of the generator.
,
are aware, the two regulating operations could
With regard to the elevator car itself, it oper
not be completely separated, so that the opera “ ates under two extremes of conditions, that is,
45
tion of varying the controller setting had no ef
full load up and full load down. When the ele
fect upon the operation of counteracting the ef vator car is operated with full load in the up‘ di
fect of load, and the operation of counteracting rection, the motor has applied thereto maximum
the e?ect of load had no eifect upon the value
power from the generator. Under these condi
of speed fixed by the controller.
tions, it is necessary for the load to be lifted 50
In controlling the operation of an elevator car against the force of gravity. When the elevator
by means of a variable-voltage or Ward-Leonard car. is operating-in the down‘ direction under full
system, a motoris provided which is arranged to
load, the functioning of the motor is reversed
be mechanically connected to the elevator car by and it operates as a generator, causing the gen
cables to eifect movement of the car in either di
erator to function as a motor and to return power
rection. Ordinarily, the motor is provided with a to the power ‘source in the event that the gen 55
separately excited ?eld winding and the desired erator is arranged to be driven by means of a
direction of movement of the car is effected by motor such as an alternating-current motor. A
reversing the polarity of voltage applied to its further variable factor which enters into the
armature. The motor is arranged to be ener
functioning of‘ the elevator car is the friction 80
We/arc aware of many regulating systems of
the prior art, applied to variable voltage motor
control apparatus, in which the motor speed was
regulated in- accordance with motor load, and
45
-
_
50
55
60
2,128,056
stalled, this friction may be relatively great but
holders tend to change their position due to the
increase in temperature thereof caused by the
overload. There is, then, a tendency for the
it lessens in effect as the car is used over a period
brushes to be slightly shifted and as a result, a
which it encounters in its movement along the
hatchway. When the elevator car is ?rst in
cumulative or di?erential compounding effect
may be present, ‘depending on the direction of
elevator car, various changes in its operating shift, which introduces another variable factor.
conditions occur which affect its speed for each ' There is also some change in the contact drop
5 setting of the controller for the main ?eld wind-' across the faces of the brushes and through the
ing of the generator; The variations in the re
brushes, due to current ?ow therethrough. This 10
19 sistance
losses of the motor, due to changes in introduces still another variable factor.
of time.
.
~
In the motor which is connected to drive the
temperature, constitute one item of variation.
These changes may be due, in part, to changes in
temperature caused, by changes in the weather‘
15 and, in part, by the loading of the motor. That
is, in the winter when it is cold, the resistance
losses of the motor will be somewhat less than
they are in the summers Likewise, when the
system is initiated, in operation after having
20 been shut down for a period, the resistance losses
are less than they are when the system has been
operating and the motor has become heated to
operating temperature. Also depending upon the
load carried by the motor, it will reach different
operating temperatures. A further variable in
the operation of the motor is the change in resistance of its main ?eld winding. Its resistance
is changed in accordance with the temperature
of the motor, and in accordance therewith, the
30 current flowing therethrough is somewhat ai
tered to change the point on the magnetization
curve of the motor at which it operates.
There are many conditions which a?ect the
functioning of the generator that is connected
to supply current to the motor, thereby causing
its power output to vary widely for the same
setting of the controller for the main field wind
ing under like conditions of load. Since it oper
ates under widely varying conditions, these re
sults are particularly accentuated. In order to
reverse the direction of rotation of-‘the motor,
the current flowing through the main ?eldwind
ing of the generator is reversed. Depending
upon the‘degree of reversal, there is a change
in the residual magnetism of the main poles,
which, to a- certain extent, will alter the output
of the generator for the same setting of the con
troller and load applied to the motor. Further
more, the change in residual magnetism of the
interpoles of the generator under these widely
varying conditions also, to a certain extent, in
troduces another variable factor. The resistance
of the main ?eld winding of the generator varies
‘In the circuit connecting the armatures of the
motor and generator, it is necessary to introduce .
joints between the conductors. ‘ The contact re
sistance of these joints varies to some extent with 15
the temperature caused by the weather and by
the current ?owing therethrough. As a result,
there is some change in the resistance of the load
circuit under these varying conditions.
-
Since all of the foregoing .variable character
istics enter into the operation of a Ward
Leonard control system employed for operating
an elevator car in a hatchway, it has been neces
sary in the past to make certain compromises
in its functioning and to permit certain varia
tions in the speed of the elevator car from the
desired speeds. It has not been possible hereto
fore to operate the elevator car in the hatchway
at speeds corresponding to the setting of the con-‘
troller of the main ?eld winding of the generator,
regardless of the load and operating conditions
of the system. As the system goes into service
it has been necessary in the past to continually
make various, adjustments in order to compen
sate for factors which change from time to time.
As a result, the maintenance expense has been
considerable and it has been necessary to pro
vide a control system which is adjustable over
a comparatively wide range, in order to permit
the necessary adjustments that were required to
be made from time to time.
‘It is, accordingly, an object of our invention to
provide a novel regulating system for regulating
a machine so that an operating characteristic,
such as speed, voltage or torque, is independently
controlled in accordance with a plurality of sepa
rate regulating variables.
As a result, for the ‘same
A further and more speci?c object of our in
vention is to provide a novel regulating system
‘for controlling the speed of a motor independ
ently in accordance with load variables so as to
eliminate the e?ect of load, and in accordance
with the position or setting of a controller.
Other objects of our invention will become evi
setting of the controller, there may be di?erent
values of current ?owing through it depending
dent from the following detailed description,
taken in conjunction with the accompanying
upon its temperature.
drawings, in which:
Figure 1 illustrates diagrammatically the ar
rangement of an elevator car in a hatchway;
Fig, 2 is a view, in side elevation, showing the
construction of a controller used for varying the
with temperature.
' i
The condition of the commutator and brushes
of the generator is another important variable
factor which affects the operation of the gen
erator. When the generator is ?rst installed,
or the commutator has been reground, the com . resistance connected in circuit with the main field
mutator is in a somewhat roughened condition, winding of the generator;
thereby causing the contact resistance between
Fig. 3 is a view, partly in side elevation and
it and the brushes to vary. As the generator partly in section, of a typical arrangement of the
goes into operation, the commutator becomes contact members of the controller shown in
'
‘
'
polished and the contact resistance of the Fig. 2;
‘Fig. 4 illustrates diagrammatically one mod
brushes correspondingly varies, although it may
reach a substantially constant value after being i?cation of my invention;
Fig. 4A shows the relationship between certain 70
70 in operation over a considerable period. Under
certain conditions, the commutator becomes of the various operating windings and contact
grooved or roughened, due to sand or other members of the relays and switches illustrated in
.
'
debris coming into contact with it and being Fig. 4;
carried underneath the brushes. When the sys
Fig. 5 illustrates diagrammatically another
system in which our invention may be employed; 7|
tem is subjected to heavy overloads, the brush
2,128,056
3
Fig. 5A illustrates the physical arrangement of
age impressed ‘across the terminals of the arma
certain of the operating windings and contact ture of the motor. Thus, the resulting ?ux due
members of the relays and switches illustrated in ' tot the differential relationship between the two
Fig. 5;
,
?eld windings, is a function of the counter
Fig. 6 illustrates schematically the arrangement E. M. F. of the motor. Since this ?ux results
of the generator armature and main ?eld wind--v from the combined action of the current ?owing
ing;
through the motor armature and the voltage
Fig.7 illustrates schematically the arrangement applied thereto, it is also a function of the load
of the regulator-generator armature and its ?eld ‘carried by the motor. The voltage which is gen
,
10 windings; and
erated in the armature of the regulator-gen
Figs. 8 and 9 illustrate diagrammatically the erator due to this resulting ?ux, is then a func 10
arrangement of certain of the control circuits
for the purpose of analysis and description of
our invention.
‘
15
In-order to practice our invention, a Ward
Leonard control system is provided in which the
motor is mechanically coupled; as set forth here
inbefore, to operate the elevator car in the hatch
way.' The motor is provided with a separately
'20 excited ?eld winding which is arranged to be en
ergized in a single direction only. A generator
is provided having its armature connected to the
armature of the motor. The control of the speed
of the motor, and consequently, of the elevator
car, as well as the direction thereof, is effected
by varying the amount and direction of the ex
citation of the main ?eld winding~~of the genera
tor.
This control may be e?ected in a few or
many steps, depending upon the type of opera
tion which is desired.
In order. to maintain the speed of the motor
at various constant values corresponding to var
ious settings of,the controller used ‘for control
ling the current ?owing through the main ?eld
winding at the generator, a regulator-generator
is provided which is ‘arranged to measure the
speed and load of the motor and the current
?owing through the main ?eld winding of the
generator. The armature of the regulator-gen
40 erator is arranged to be connected in series cir
cuit relation with the generator ?eld winding so
tion of the speed-of the motor and the load car
ried thereby.
'
,
It is desirable that any change caused by the
voltage generated in the regulator-armature and 15
a?eeting the current ?owing through the main
?eld winding of the generator be immediately re
?ected in the voltage generated in the armature
of the regulator-generator. Such action is de
sired in order to prevent hunting of the system. 20
As soon as a voltage appears in the armature of
the regulator-generator, indicating that the speed
of the motor has departed from the desired speed,
a change in the flow of current through the main
?eld winding of the generator takes place ini such
direction as to tend to restore the- speed of vthe
motor to the desired speed. If some means is not
provided for immediately effecting a correspond
. ing change in the corrective voltage generated in
the armature vof the regulator-generator the re
sulting change in‘the ?uxes of the series and main
?eld windings of the regulator-generator in re
sponse to the corrective effect-twill take place too
late. As a result, .the speed of the“ motor will. be
altered more than is desiredand hunting will 35
result.
-
'
In order to make the correction applied by the .
regulator-generator proportional to the departure
of the speed of the motor. from the. desiredspeed
corresponding to a particular setting of the con
troller for the main ?eld winding of the genera.
40
that the voltage generated in the armature in ~ tor, a differential ?eld winding is provided in the 1
response to the speed and load of the motor and
the current ?owing through the generator ?eld
winding will cause a, current to ?ow through the
main generator ?eld winding, which will be a
regulator-generator, and is connected ‘in series
circuit relation with the main ?eld winding of the
generator. Thus, any change in current which 45
?ows through the main generator ?eld winding is
immediately re?ected in the voltage which is gen
function of the departure of the motor speed
from a predetermined value-corresponding to the ' erated by the armature of the regulator-genera
particular setting of the controller of the main
tor. Itiis then unnecessary to await the correc
?eld winding. Under certain load and operating tion in the speed of the motor, as re?ected in the
conditions, no voltage will be generated in the change in the ?uxes generated by the series and,
armature of the regulator-generator since un
main ?eld windings of the regulator-generator
der these conditions, the speed of the motor cor-' to correspondingly a?ect the voltage generated by
responds to the setting of they controller. For the armature of ‘the regulator-generator. The
all other conditions, however, a voltage will be differential ?eld winding of the regulator-genera
generated in the armature of the regulator-gen
tor is» arranged to generate a ?ux in the same di 55
eratoi‘ in such direction and value as to cause rection as ‘the ?ux generated by the series ?eld
the required current‘ to ?ow through the main winding of the regulator-generator and, there
?eld winding of the generator to operate the mo
fore, it opposes or is di?erentially related to the
¢tor at the desired speed.
?ux which is generated by the main ?eld winding 60
" In order to measure the speed and load ap
of ' the regulator-generator. There is always,
pI'iedQto the ‘motor, the regulator-generator is then, a certain relationship between the speed
provided with ya series ?eld winding through and load of the motor and the corrective effect
which all or a portion of the currentfrom the caused thereby in altering the ?ow of current
generator ?ows. The regulator-generator is also. through the main ?eld winding of the generator.
65
provided with a main ?eld winding which is con
As a result, the system is ,free from hunting and
nected to be responsive to the voltage applied the speed of the motor is maintained at predeter~
to the motor. These-two ?eld windings are dif
mined values corresponding to various settings
ferentially related so that the resulting ?ux is of the controller regardless of the many variable
70 a- function of the speed of the motor, as meas
conditions which would otherwise a?ect the speed 70
ured by its counter E. M. F., that is, the?ux gen
and cause it to change from the desired values.
erated by the series ?eld winding is proportional
As has been stated hereinbefore, it is desirable
to the IR drop of the motor armature,-and the to effect a corrective action in the current ?ow
?ux generated by the main ?eld winding of the ing through the main ?eld- winding of the gen
75 regulator-generator is proportional to the volt
erator by means of the regulator-generator, with
p-4
2,128,056
out altering the current ?ow through the main
?eld. winding from the controller. It is then pos-.
sible to maintain a precise relationship between
the speed of the motor and the corresponding
5' movement of the elevator car and the various
settings of the controller, regardless of the load
or other variable conditions which affect the op
eration of the motor.
We have discovered that a Wheatstone bridge
10 circuit may be employed to effect the desired in
dependent control of the current ?owing through
the main ?eld winding of the generator. A bal
anced Wheatstone bridge circuit is provided in
which the differential ?eld winding and the main
15 generator i'leldv winding are connected in series
circuit relation and form a part, or all of one of
the branches. The armature of the regulator
generator is connected across one pair of opposite
terminals of the Wheatstone bridge circuit while
go the.remaining pair of terminals is connected
through the controller to the independent control
means of a generator G having, as shown in Figs.
4, 5 and 6, an armature Ga and a main ?eld wind
ing G]. The armature Ga of the generator G is
arranged to be mounted on a shaft it which may
be driven by any suitable motive means, such as
an induction motor (not shown), that may be
connected to an alternating-current source of
supply.
'
In order to control the functioning of the sys
tem, a regulator-generator R is provided having
an armature Ra which may be mounted on the
shaft I‘. As shown in Fig. 7 of the drawings, the
regulator-generator R is provided with a shunt
?eld winding Rf, differential ?eld winding Rd
and a series ?eld winding Rs. As indicated by
the arrows, the shunt ?eld winding R] is arranged
to generate a flux in a direction opposite to the
direction of‘ the fluxes generated by the differen
tial ?eld winding Rd and the series ?eld winding
R8 of the regulator-generator.
The particular
connections for the various ?eld windings and
source. With such an arrangement, it is possible the armature of the regulator-generator in the
to vary the current ?owing through the. branch control systems are illustrated in Figs. 4 and 5 of
of the bridge containing the main ?eld winding the drawings, and they will be set forth in detail
of the ‘generator by means of the controller, iri
hereinafter.
‘ '
25
dependently of the current flow therethrough
In response to the operation of the master
from the armature of the regulator-generator, switch MS, up or down reversing switches U and
and vice versa. In’order to show that this rela
D are operated. On the operation of either of
tionship exists, a detailed mathematical analysis the up or down switches, an auxiliary switch I
‘0 of this system will be set forth hereinafter.
is operated to complete a circuit for energizing the
Referring now particularly to Fig. 1 of the operating windings of the inductor relays E and F.
drawings, the ‘reference character l0 designates,
generally, an elevator car which may be sup
ported in a hatchway or shaft by means of a cable
II which is passed over a sheave l2 and balanced
by suitable counterweights ll. The elevator car
II is provided with a slowdown-inductor relay E
and a landing inductor relay F. The slowdown
inductor relay E is provided with normally closed
‘0 contact members El and E2 while the landing in
ductor relay 1'' is provided with normally closed
‘ contact members Pi and F2.
When the operat
ing winding of the slowdown inductor relay E is
‘energized, no action takes place until the contact
members El or E2 come into proximity, respec
tively, ,with- the inductor plates UE and DE, de
pending upon the direction of travel of the ele
vator car. Assuming that the elevator car ill is
traveling in the up direction, and that the oper
ating winding of the slowdown inductor relay E
is energized, the contact members El will be
opened as soon as they are moved into proximity
to the inductor plate UE. A resulting control
function then takes place which will be set forth
“ hereinafter. The contact members Pi and P2 of
the landing inductor relay F are also opened when
‘they come into proximity, respectively, to the in
,_ductor plates UF and DI". The elevator car I! is‘
also provided with a master switch MS having
three positions, the extreme outer positions cor
responding to up and down movement of the car,
and the central position to a position to stop the
car.
‘
In order to operate elevator car ill in the
65 hatchway, a Ward-Leonard control system is pro
vided which comprises a motor M that is arranged
to be mechanically coupled, as illustrated, to the
sheave l2. As shown in Figs. 4 and 5 of the draw
ings, the motor M comprises an armature Ma and
70 a main field winding M]. the latter being arranged
to be separately excited from normally energized
conductors Li and L2. A brake Bis provided hav
ing a brake—releasing winding Bw for releasi
it on energization of the motor M.
75
'
The motor M is arranged to be energized by
As soon as either the up or the down switch
U or D is operated, a potentiometer Pi is con
nected‘ across the conductors Li and L2. The
current flowing through the potentiometer Pi is
in one direction when the up reversing switch U
is energized, and in a. reverse direction when the
down reversing switch D is energized.
In order to accelerate the motor M, the cur
rent flowing through the main generator ?eld
winding G] is increased by increasing the voltage
applied thereto from the potentiometer Pl. This
voltage is gradually increased by the successive
closing 'and opening of contact , members C2
through Cl, which as shown in Figs. 2 and 3 of
the drawings, are arranged to be successively op
erated by means of a control motor CM. The
control motor CM is arranged to operate through
a reduction gearing mechanism ii to rotate a
shaft IS on which a series of cams ll, composed of
insulating material, is mounted. As shown more
clearly in Fig. 3 of the drawings, a cam i1 is
arranged to engage a roller IS .on the periphery
thereof and to normally hold a movable contact
member l9 out of engagement with a ?xed con
tact member 20. The cam l‘! is provided with a
recessed portion 2i which is arranged to permit
the roller l8 to move under the. influence of a
biasing spring 22, so that the movable contact
member I9 is permitted to engage the ?xed con
tact member 20. It will be understood that the
cams l1 may be positioned on the shaft ii in any
desired relative positions to effect the sequential
opening and closing of the contact members CI
through C8, as may be desired. In order to stop
the operation of the control motor CM after it
has reached its limit of travel, contact members
C8 and Gill are provided. The contact members
Clli are arranged to remain in the-closed position
until the control motor has‘reached its limit 'of 70
travel after being initially energized. At this time
contact members Clll areopened to terminate
further motion of the control motor CM in this di
rection, contact members C8 having been closed
as soon as the-control motor CM was energized. TI
2,128,066
The contact members C9 are arranged to remain
in the closed position until the control motor CM
has been restored to the initial position, at which
5
bridge circuit if the bridge resistors are propor
tloned so that
’ ‘
. time they are opened. It will be understood that
the cams l1, associated with these contact mem
bers, may be suitably arranged to e?fect this de
sired operation. As illustrated in Fig. 4 of the
drawings, the control motor CM is provided with
an armature CMa and a separately excited ?eld
10 winding CM)‘. The direction of rotation of the
armature CMa is effected by reversing the polar—
ity of the voltage applied thereto from the con
ductors Li and L2 by means of a speed relay V.
It is desirable to independently control the flow
15 of current through the main ?eld winding Gf of
the generator from two sources, one of the sources
comprising the energized conductors LI and L2
across which the potentiometer PI is connected,
and the other source comprising the armature Ra
20 of the regulator-generator. For this purpose the
Wheatstone bridge circuit is employed, compris
ing the customary four branches, three of which
may be resistors T1, T2 and m, the remaining branch
comprising the differential ?eld winding Rd of
.25 the regulator-generator and the main ?eld wind
ing Gf of the generator. The armature Ra of the
regulator-generator is connected across a pair
of opposite terminals of the bridge circuit while
the remaining pair of terminals is connected
80 through the potentiometer Pl to the energized
conductors LI and L2. The series ?eld winding
Rs of the regulator-generator is arranged to be
connected, as illustrated, in the circuit connect
ing the armatures Ga and Ma of ,the generator
and motor, respectively. ' A shunt S may be pro
vided for adjusting the ?ow of ,current through
the series ?eld winding Rs. 'The shunt ?eld wind
When the latter relationship is employed, the
total value of resistance losses in the bridge cir
cuit may bemade- large or small, depending upon
the numerical values chosen, without effect upon
the regulating action. Accordingly, we prefer to
design the bridge circuit in accordance with the 10
latter relationship, and to‘use numerical values
such as to provide low resistance losses or even
minimum loss.
'
In the appended claims, the term “balanced
Wheatstone bridge circuit” is used to denote a
bridge'in the sense that the ratio of two adjacent
impedances is equal to the ratio of the two re
maining impedances,v whether or not any of the
impedances are equal.
_ ‘
15'
.
The currents ?owing through the various 20
branches vare indicated by arrows to which the
reference characters 11, 12, I3 and I4 are applied,
as indicated. In Fig.‘ 9 of the drawings, the re
sistance of the generator-armature Ga is indi
cated by the resistor 15 and the corresponding
resistance of the motor armature Ma is indicated
by the resistor ‘1'7.
In order ‘to show that the current ?owing
through the generator ?eld winding G1‘ in one of
the arms of the bridge circuit may be independ 80
ently changed by altering either the control volt
age or the voltage supplied by the regulator
generator R, the following derivation for the
current flowing through this winding is set
forth, with reference to Fig. 8 of the drawings,
based on the assumption that the relationship of
ing Rf of the regulator-generator is connected‘ resistances in the bridge circuit is such that
'40
through a resistor Ts across the terminals of the
motor armature Ma. The resistor T6 is employed
in order to reduce the heat loss in the shunt ?eld
winding R1’, and consequently, the e?ect of a.
change in its resistance due ,to temperature rise,
‘to a minimum.
ii
1'2
is
1'4
Adding voltages around the bridge circuit:
E,,—I
1. EI.=I1X'1+I3I3 and I1=_r1_3r3
I
45
In order to permit an analysis of the Wheat
stone .bridge circuit and its functioning in con
junction with the regulator-generator R, the
circuits in Figs. 8 and 9 are shown. The voltage
ES represents an independent control voltage
50 which may be obtained from‘the potentiometer
PI. The four branches of the bridge are identi
?ed by the reference characters 1'1, r2, rs and r4; ‘
the resistance 7'3 corresponds to the sum of,
resistances‘ of the ?eld windings Rd and GI.‘
The voltage ER is that which is obtained from
the armature Ra of the regulator-generator R in
Adding currents at the upper and lower junc
tions of the bridge circuit:
‘
4. I1+I2=I3+I4 and I3=I1+Y2—-I4
resistance in ohms of the various elements com
prising the Wheatstone bridge circuit that we
have employed in a concrete embodiment of the,
invention are tabulated below.
65
_
Substituting values of I1, I2 and I4 from Equa
tions 1 to 3 in Equation 4. '
.response to the combined action of the series ?eld
winding Rs, shunt ?eld winding R)‘ and the dif
ferential ?eld winding Rd. The various values of
,
'
_E,—-I3r3
E,+E1z—IaIa__Isl'a_ER
1‘1
+
1'2
I
1'4
5' I3_
Multiplying 5 out and collecting terms:
=
60
Eat4(rl+r2)
l'il'zn + 12131‘; + r1r3r4 —|— 1-11-2113
.
In our parent application, Serial No. 38,770,
vmentioned above, we disclosed a design of the
.
‘
Enrl(f2+la)
1'11'2l'4 + 121311 + F1131! + 111213
bridge circuit such that 11:7‘: and 13:14. ' Al
Equation '6 may be. simpli?ed by using the as
though such a design is entirely satisfactory for
sumption mentioned above, that
-
the regulation of the elevator motor speed in ac
70 cordance with theprinciples of our invention,
the resistance losses in the bridge circuit were
somewhat high. We have found that all of the
regulating advantages of the system of our parent
application may be retained, and the further ad
75 vantage secured of minimizing the losses of the
70
From this relationship, rm equals rzra. The
last term--~~(r1rzrs) in the denominator of the
Esterm of Equation 6 may accordingly be re
written‘ as r1214.
(7'27‘37‘4)
Similarly the second term
in the denominator of ER term of 75
2,128,056
Equation 6 may be written
rm’.
Making
these substitutions, Equation? becomes
R: of the regulator generator may be represented
by’ the following equation:
Err-1513s
14. 1,,= Irt' R!
7. I‘: v
E|rl(rl + I!)
+
fifzri + l'zral’i + titan + Ii'n
E3110: + fa)
lira" + fin’ + fifth "i" Iifzfs
10
Rearranging denominator terms and factoring,
Equation 7 becomes
EJKH + H) +
f4(fi+ “)(h + 1's)
which reduces to
15
.
8. I3:
It + n
+
Employing the above relationships and the
winding G].
It is desirable, as set forth hereinbefore, to
maintain a predetermined relationship between
the speed of the motor M and the setting of the
controller as represented by the control voltage
Es regardless of the variable characteristics of
the system or the direction of travel of the ele
vator car. The regulator-generator R serves as
30 an automatic compensator to e?ect this desired
relationship. When it is employed there is a
constant relation between the speed of the ele
vator car or the motor M and the applied control
voltage, which relation, due to the regulator
generator R, is una?ected by the variable char
acteristics of the system. This relationship will
be shown in the derivation which follows, refer
ence being had to Figs. 8 and 9 of the drawings.
The voltages generated by the regulator
generator, when the field windings are individ
ually excited, may be represented by the fol
lowing equations?
.
9. Voltage due to excitation of regulator
series ?eld winding Rl=k1I88
11.
Voltage due to excitation of regulator
main ?eld winding Ry=k3Iar
Voltage due to excitation of regulator
differential ?eld winding Ra=k1lad
50 The constants, in,- kg and k; are obtained from
the magnetization curves of the regulator
generator R, when it is individually excited by
the various ?eld windings.
'
The ‘voltage En generated by the regulator
55 armature Ra equals the sum of the individual
voltages generated by the three field windings
when they are simultaneously energized. It will
be recalled that the flux generated by the shunt
?eld winding R1 opposes the flux generated by
60 the ?eld windings R3 and Rd. The regulator
armature voltage En may, accordingly, (neglect_
ing saturation)v be represented by the following
equation:
65
We have found that it is desirable to make the
sum of the resistances r; and n of the two lower
legs of the bridge equal to the constant k1. Em
ploying this relationship and noting that I: is
70 identical with Ina, Equation 8 may be rewritten
as follows:
+ 1:
10
'
ER
It will now be observed that either the con~
10.
J51.
E'ri +1:
Solving 15 for Ea:
trol voltage E, or the regulator voltage Ea may be
altered to independently e?ect changes in the
current I: ?owing through the generator ?eld
k
The current through the shunt field winding
15
characteristics of known machines, a typical set
of constants for an ‘average elevator installation
has been calculated and is tabulated below:
20
r1=73 ohms
rz=66 ohms
Rr=727 ohms
Ra=5.9 ohms
r4=81.l ohms
r5=.046 ohm
Ts=423 ohms
r1=.13 ohm
k1=.193 volt per ampere
kz=1710 volts per ampere
kg: 171 volts per ampere 25
Substituting the appropriate values in 16
17. EG=.71E:+.176I:
30
Since the resistance of the regulator series
field winding Rs is negligible and the current
flowing through the main ?eld winding R; is also
negligible as compared to the current ?owing to
the motor M, both of these values may be neglect
ed and the counter E. M. F. of the motor M, or
its speed with constant excitation may be repre
sented as:
' ‘
40
I Substituting the appropriate values of T5 and T1, v
19. Em==Ea—.176Im
Combining 1'7 and 19
20. Em:.71E-!
Equation 20 shows that the speed of the mo
tor M, as represented by its counter E. M. F., or
the speed of the elevator car will always be di
rectly proportional to the control voltage Es re
gardless of the variable characteristics in the op
eration of the system.
In describing the operation of the system shown a
in Fig. 4 of the drawings; it will be assumed that
the conductors Li and L2 have applied thereto a
suitable control voltage; that the generator G
and the regulator-generator R are being operated
at the proper speed; and that it is desired to move 60
the elevator car ill in the up direction. The op—
erator then moves the master switch MS to the
up position to effect the energization of the op
erating winding of the up reversing switch U, as
well as the energization of the operating wind 65
ing of the auxiliary switch X. The circuit for
e?ecting the energization of these windings may
be traced as follows:
Ll, MS, up contacts, Fl, U, K. gate contact,
door contacts, L2
a
13. ER=k3Igd—El,g+_3r_:
75
’ Substituting Equations 13 and 14 in 12 to elimi
nate Ea and Ina
At contact members US, a holding circuit is pro
vided around the master switch MS. The brake
B is released by the energization of the brake
winding Bw in response to the operation of the
' 7
' 2,128,058
up reversing switch U./ The circuit for releasing
the brake winding may be traced as follows:
sense, proportional to the degree of variation in
the speed of the motor M from the desired speed.
when it is desired to stop the elevator car at
Ll, Bw, ULLZ
a particular ?oor, the operator centers the master
The potentiometer PI is connected directly ' switch, thereby completing a circuit for energiz
across the conductors Li and L2 on the closure‘ ing the operating winding of the slowdown induc
of contact members U2 and U3'in‘ response to the itor relay E. This circuit may be traced as fol—.
.» operation of the up reversing switch U. Current
‘ is then caused to flow through ‘the main genera
lows:
Ll, MS, stop contacts, E, XI, L2.
10 tor ?eld winding G! in part because of the voltage
10
which is obtained-from the ?rst section of the
potentiometer PI, due to the fact that contact
As soon'as the contact members El come into
members Cl are closed, and in part because of >
opened and the previously traced energizing cir
cuit for the operating winding of the speed relay
the voltage which is obtained from the ‘arma
15 ture Ra of theregulator generator R.
.
The operating winding of the speed relay V is
energized in response to the operation of the up
reversing switch U over a circuit which may be
traced as follows:
proximity with the up inductor plate UE, they are .
Vis interrupted.
Contact members VI and V4 are 15
accordingly reclosed to effect energization of the
armature of the control motor CMa in reverse di
rection to effect the operation‘ of the contact
members CI through C8 in'a reverse sequence.
The circuit for now energizing the control motor 20
armature CMa may be traced as follows:
20
As a result of the energization of the speed
31.4, v4, CMa, VI, on, L2.
relayIV, a circuit is completed for energizing the
25 armature CMa of the control motor CM.
circuit may be traced as follows:
This
Ll, V2, CM‘a, V3, G10, L2
‘The contact members Cl are then‘ opened and
30 the remaining contact members C2 through C1
are successively closed and opened. contact mem
bers C8 being closed but not opened, thereby in
creasing the voltage which is applied to the main
generator ?eld winding Gf to correspondingly in
35
crease the voltage which is applicd to the arrra
ture Ma of the motor M. As soon as the contact
members CH3 are opened, the armature CMa is
deenergized, contact members C8 remaining
. closed. . A further result of the operation of the
40 speed relay V is to open contact members VI,
thereby inserting the resistor Ar entirely in series
circuit relation with the armatureRa. Depend
ing upon the operating conditions as set forth
hereinbefore, it may in some‘in'stances be desir
The contact members C1 through C2 are suc 25~
cessively closed and opened to effect a decrease
in the ?ow of current through the main generator
?eld winding Gf. During this interval the regu
lator-generator R is effective to maintain the
speed of the motor M at values corresponding to
the contact members which are closed.
As a re
sult, regardless of the variable conditions or load
ing of the elevator system, or the connections to
the potentiometer Pl, the elevator car II] will be
decelerated in accordance with a deceleration 35
pattern determined by the resistance values be
tween the contacts C1C2, etc. and by the relative
angular positions of the corresponding cams.
A further result of the deenergization of the
speed relay V is to close contact members V5 and
to complete an obvious energizing. circuit for the
operating winding of the landing inductor relay
F in parallel with the operating winding of the
45 able to provide the contact members VI in the slowdown inductor relay E. As soon as contact
normally open condition and to close them on > members Fl, come into proximity with the up
operation of the system at‘ full speed.
As has been set forth hereinbefore, it is desir
able that speed of the motor M be at a certain
50 value for each of the steps vof control voltage
obtained from the potentiometer Pl. It is then
possible vto obtain a smooth acceleration curve
which will be unaffected by the many variables
in the system that have been set forth in detail
55 hereinbefore. In addition, it is also desired that
the same speed relationship exist when the con
tact members CI through 08 are operated in a
reverse order to effect the deceleration of the
motor M and the'elevator car driven thereby‘. .
60
We have found that the desired speed relation
ship will exist regardless of the variable charac
inductor plate UP, the previously traced energiz-v
ing circuit for the operating winding of the up
reversing switch U and the auxiliary switch X, is
interrupted. These switches are deenergized.
The potentiometer PI is disconnected from the 50
conductors LI and L2 and the previously traced
energizing circuit for the brake winding Bw is
opened. The brake B is then applied and the
elevator car I0 is brought to rest at the desired
?oor.
i
‘
.
,
In order to further point out the application of
our invention, reference may be had to the cir
cuits shown in Fig. 5 of the drawings. The cir
cuit connections there shown are identical with
those shown in Fig. 4, with the exception that the
to
teristics of the elevator system, or the connections “ potentiometer PI and the control motor CM are
to the potentiometer Pi, when the regulator
omitted. Also, the speed relay V is arranged to
generator R is employed and its ?eld windings are,
connected as shown in conjunction with the bal
anced Wheatstone bridge circuit. Because of the
short circuit an accelerating resistor Ar which is
connected in series circuit relation with the bridge
circuit to permit the operation of the motor M to
connection of the shunt ?eld winding R1’ in series
full speed in one step.
circuit relation with the main. generator ?eld
winding‘Gf in one of the branches of the bridge
As shown in Fig. 5 of the drawings, the arma
ture Ra. of the regulator-generator is connected
70 circuit, the changes which are introduced to- e?‘ect
a corrective action through the generator (3- are
across two of , the terminals of a Wheatstone
'
-
'
_
bridge, as set forth hereinbefore, one leg of which
immediately re?ected in the voltage which is gen- ' comprises the differential ?eld winding Rd of
erated in the armature Ra of the regulator-gen
the regulator-generator, and the main ?eld wind
erator.v As a result, the corrective effect which is ing G] of the generator G. The remaining legs
applied by the vregulator-generator R is, in a.
70
of the Wheatstone bridge comprise resistors n, 75.
8
2,128,066
r: and n. The terminals of the Wheatstone
bridge not connected tothe armature Ra are ar
ranged to be connected to the conductors LI and
L2 through the accelerating resistorAr, and these
connections may be reversed by means of the up
and down reversing switches U and D.
Since the sequence of operation of the system
shown in Fig. 5 of the drawings is somewhat
similar to that set forth hereinbefore in con-
10 nection with, Fig. 4, only the portion necessary
to illustrate the function of the Wheatstone bridge
will now be set forth.
As soon as the master
switch MS is operated, to the up position for ex
ample, contact members U2 and U3 are closed to
15 connect the Wheatstone bridge in series circuit
relation with the accelerating resistor Ar and
across the conductors ,LI and L2. The brake
winding Bw is energized to release the brake B
and ‘the motor M is then energized to move the
20 elevator car in the up direction. The voltage
which is applied to the main generator ?eld wind
ing G! of the generator G is then a function of the
voltage existing across the conductors LI and L2,
less the voltage which is consumed in the ac
without altering the effect of the other source in
the functioning of said device.
3. In a system for controlling the functioning
of an electrical device, in combination, a Wheat
stone bridge circuit including said device in one 5
of the branches thereof, means for connecting
one control source between opposite terminals of
said bridge circuit, means for connecting another
' control source between the remaining pair of
terminals of said bridge circuit, and means re
sponsive to the combined effects of said control
sources for controlling the functioning of said
second control source.
'
=
4. In a system for controlling the functioning
of an electrical device, in combination, a Wheat 15
stone bridge circuit includng said device in one
of the branches thereof, means for connecting
one control source between opposite terminals of
said bridge circuit, means for connecting another
control source between the remaining pair of ter
minals of said bridge circuit, means for independ
ently altering the effect of each of said control
sources to independently effect corresponding
changes in the functioning of said device, and
celerating resistor Ar, and is further proportional
means responsive to the combined effects of said
to the voltage which is generated in the armature
As is set forth
said second control source.
' Ra of'the regulator-generator.
hereinbefore. the voltage which is generated by
the armature Ra may be independently applied to
30 the generator ?eld winding GI and this effect will
be entirely independent of the effect which is
caused by the voltage which is applied thereto
from the source represented by the conductors
LI and L2.
When the speed relay V is energized, contact
members Vi are closed to short circuit the ac
celerating resistor Ar. The Wheatstone bridge
circuit vis then connected directly across the con
ductors Li and L2. The regulator-generator R
40 then functions to maintain the proper current in
the generator ?eld winding GI, so that the motor
M will operate at a fixed speed regardless of the
load or variableconditions affecting it.
Since certain further changes may be made in
45 the foregoing constructions and different em
bodiments of the invention may be made without
departing from the scope thereof, -it is intended
that all matter shown in the accompanying draw
ings or set forth in the foregoing description shall
50 be interpreted as illustrative ‘and not in a limit
' ing sense.
We claim as our invention:
1. In a system for controlling the functioning
of an electrical device, in‘ combination, a Wheat
:a in stone bridge circuit including said device in one
of theubranches thereof, means for connecting
one control source between opposite terminals of
said bridge circuit, means for connecting another
control source between the remaining pair of
60
terminals of said bridge circuit, and means for
altering the effect of one control source to effect
a change in the functioning of said device with
, out altering the e?ect of the other source in the
functioning of said device.
2. In a system for controlling the functioning
of an electrical device, in combination, a balanced
Wheatstone bridge circuit including said device
in one of the branches thereof, means for con
necting one control source between opposite ter
minals of said bridge circuit, means for connect- ‘
ing another control source between the remaining
pair of terminals of said bridge circuit, and means
for altering the effect of either control source to
effect a change in the functioning of said device
control sources for controlling the functioning of
“
5. In a system for controlling the functioning
of an electrical device, in combination, a bal
anced Wheatstone bridge circuit including said
device in one of the branches thereof, means for‘
connecting one control source between opposite
terminals of said bridge circuit, means for con
necting another control source between the re
maining pair of terminals of said bridge circuit,
and means responsive to the combined effects of
said control sources for controlling the function
ing of said second control source.
‘
6. In a system for controlling the functioning
of an electrical device, in combination, a balanced 40
‘Wheatstone bridge circuit including said device
in one of the branches thereof, means for con
necting one control source between opposite ter
minals of said bridge circuit, means for connect
ing another control source between the remaining
pair of terminals of said bridge circuit, means
for independently altering the effect of each of
said control sourcs to independently effect cor
responding changes in the functioning of said
device, and means responsive to the combined 50
effects of said control sources for controlling the
functioning of said second control source.
7. In a system for controlling the functioning
of an electrical device, in combination, a bal
anced Wheatstone bridge circuit including said 65
device in one of the branches thereof, means for
connecting one control source between one pair
of opposite terminals of said bridge circuit, means
for connecting another control source compris
ing the armature of a generator between the re
maining pair of terminals of said bridge circuit,
means for controlling the voltage generated by
said armature, and means responsive to the com
bined effects of said control sources for also con
trolling the voltage generated by said armature.
8. In a system for controlling the functioning
of an electrical device, in combination, a bal
anced Wheatstone bridge circuit including said
device in one of the branches thereof, means for
connecting one control source between one pair
of opposite terminals of said bridge circuit,
means for connecting another control source com
prising the armature of a generator between the
remaining pair of terminals of said bridge circuit,
65
2,128,056
means for controlling the voltage generated by
said armature, and a ?eld winding in said gen
erator connected to be responsive to the current
?owing through said device for also controlling
the voltage generated by said armature. '
9. In a system for controlling the functioning
of an electrical device, in combination, a bal
9
ture of a generator andlone-o‘f the legs of said
bridge'having connected in circuit a?eld in said
generator, the resistance of said leg plus the re
sistance of the adjacent leg that is in series cir
‘ cuit relation with said armature and said ?eld;
substantially equalling numerically the volts gen
erated by said armature with one ampere of cur
' anced Wheatstone bridge circuit including said
, device in one of the branches thereof, means for
1
a connecting a'variable control source between one
I
rent flowing in said ?eld.
15. In a system for controlling the voltage of
pair of opposite terminals of said bridge circuit,
Wheatstone bridge circuit with variable poten
tial sources connected across the diagonals of
said bridge one of said sources comprising the
i l
means for connecting another control source
comprising the armature oi’ a generator between
the remaining pair of terminals of said bridge
15 circuit, means for variably controlling the volt
armature o! -a second generator, and one of the
legs of .said bridge comprising a ?eld winding of 15
age generated by said armature, and a ?eld wind
‘ing in said generator connected in series circuit
relation with said device for opposing the func
said first mentioned generator and a ?eld‘ wind
ing of said second generator in series circuit
tioning of said last-named means in controlling
plus the resistance oi.’ the adjacent leg that is in
series circuit relation with the armature‘oi' said 20
20 the voltage generated by said armature, where
by the current ?owing through said device is in
dependently a function of the variable voltage
from said variable control source and the voltage
generated by said armature.
I
10. me system for controlling the functionin
0! an electrical device, in combination, ‘a pair of
circuits disposed to be connected to a ?rst con
trol source, said device being connected in‘ one
of said circuits; means for connecting a second
relation, the resistance‘of said ?eld containing leg
second generator and the leg containing said
?elds substantially equalling numerically the
volts generated by the armature oi! ‘said second
generator with one ampere of current ?owing in
the said ?eld of said generator, and the resistance
01' the legs of said bridge being so proportioned
that the resistance of the leg containing said
one of said circuits to a point ‘of substantially
?elds dividedby the said adjacent series circuit
leg equals the resistance of the other leg adjacent
to the ?eldcontaining leg divided by the resist
ance of the leg opposite said fields.
equal potential in the other of said circuits, and
means for varying; the lpotentlalrotone of said
16. In a system for controlling the voltage of
the'armature 01' a generator. in combination, a
control source from‘a point of given potential in
sources to vary the current ?owing in said device.
85
the armature of a generator, in combination, a 10
Wheatstone bridge circuit with variable poten
11. In a system for controlling the functioning ' tial sources connected across the diagonals oi’ said
01’ an electrical device, in combination. a pair
7 of circuits disposed to be connected to a ?rst con
bridge one of said sources comprising the arma
ture of a second generator, and one of the'legs
trol source, said device being connectedv in one
of said circuits; means for connecting a second
40 control source from a point 01' given potential in
one of said circuits to a point of substantially
?rst mentioned generator and a ?eld winding of
equal potential in the other of said circuits,
means for varying the potential of said ?rst
source andadditional means for varying the po
tential oi’ said second source.
‘
12. In a system-tor controlling the functioning
of an electrical device, the combination, a Wheat
stone bridge circuit with variable potential
sources connected across the diagonals of said
50 bridge, one of the legs of said ‘bridge comprising
said. device, the resistance of the legs of said
bridge being so proportioned that the resistance
of the leg containing said device divided by the
resistance of either adjacent leg substantially
55 equals the resistance of the other adjacent leg
divided by the resistance of the leg opposite.
13. In a system for controlling the functioning
. of an electrical device, the combination, a Wheat
stone bridge circuit with variable potential
of said bridge comprising a ?eld winding of said
said second generator in‘ series circuit relation,
the resistance of said ?eld containing leg plus the
resistance of the adjacent leg that is vin series
40
circuit relation with the armature of said second
generator and the leg’ containing said ?elds sub
stantially-equalling numerically the volts gener 45
ated by the armature of said second generator
with one ampere oi’ current ?owing in the said
?eld of said generator, and the resistance oi’ ,the
legs of said brldgebeing so proportioned that the
resistanceof the leg containing said ?elds divided 50
by the said adjacent series circuit leg equals the
resistance of the other leg adjacent to the ?eld
containing leg divided by the resistance of the
leg opposite said ?elds and a second ?eld in said
second generator connected across the armature
of said ?rst mentioned generator.
55
'
1'7. In a system for controlling the voltage of
the armature of a generator, in combination, a
Wheatstone bridge circuit with variable potential
sources connected across the diagonals of said sources connected across the diagonals of said 60
bridge. one of the legs of said bridge comprisingr bridge one of said sources comprising the arma
said device, the-resistance of the legs of said ture of a second generator, and one, of the 'legs
bridge being so proportioned that the resistance I of said bridge comprising a ?eld winding of said
of the leg containing said device divided by the ?rst mentioned generator and a ?eld winding of
_65 resistance of either adjacent leg substantially ' said second generator in series circuit relation,
equals the resistance of the other adjacent leg
_ divided by'the resistance of the leg opposite.
whereby varying either source varies its effect
on said device without altering the effect of the
vother source on said device.
14. In a system for controlling‘the functioning‘
' of an electrical device, the combination, a Wheat
stone bridge circuit with variable potential
'75
sources connected across the diagonals of said
bridge, one of said sources comprising the arma
the resistance of said ?eld containing leg plus
the resistance of the adjacent leg that is in‘series
circuit relation with the armature of said‘seco'nd
generator and the leg containing said ?elds sub- '
stantially equalling numerically the volts gener»
ated by the armature of said second generator
with one ampere of current ?owing in the said .
?eld of said generator, and the resistance of the
legs of said bridge being so proportioned that the
resistance of the leg containing said ?elds divided 55
1O
'
2,128,050
'1)? the said adjacent series circuit leg equals the
resistance of the other leg adjacent to the ?eld
?eld being so connected that its ampere turns ,
oppose those of the ?rst mentioned ?eld of said
containing leg divided by the resistance of the
second generator.
leg opposite said ?elds and a second ?eld in said
a second generator connected across the armature
of said ?rst mentioned generator, said second
‘
I
DANILO SANTINI.
KENNETH MARTIN WHITE.
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