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Nov. 26, 1946.
’
E. E. MOYER
' 2,411,145
ELECTRIC CONTROL CIRCUIT
Original Filed Oct. 29, 1941
lg$5 .-kELSE
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Inventor
Elmo E; Meyer,
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His Attorne‘g.
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2,411,745
Patented Nov. 26, 1946
UNITED srA'rEs PATENT‘ OFFlCE
ELECTRIC CGNTROL CIRCUIT
Elmo E. Moyer, Scotia, N. Y., assignor to General
Electric Company, a corporation oi‘ New York -
Original application October 29, 194i, Serial No.
416.3%. Divided and this appiicaticn February
25, 1343, Serial No. d'i'l,il3l
'
ll
My invention relates to electric control circuits
-. ticulariy to improved electric con“
trol circuits for accomplishing variable energiza
tlon oi‘ a load circuit, such as an electric motor,
by the use of electric valve translating apparatus“
This application is a division of my application
sér, No. 416,974.», filed October 29, 1941, entitled
It is an object of my invention to provide a
new and improved electric control circuit.
It is another object of my invention to provide
a new and improved electric control circuit for
an electric valve translating apparatus for efiect=
ing variable energization of a load circuit which
provides for a predetermined initial energizatlon
of the load.
'
Electric control circuit, and assigned to the same
It is still another object of my invention to
assignee as the present invention.
In control systems employing electric valve 10 provide a new and improved electric control sys
tem I employing self-synchronous type motion
translating apparatus for e?ecting variable ener
transmitting devices which insures smooth regu
gization of a load circuit and particularly in sys
lating action under all operating conditions.
terns where the load circuit comprises a motor
Briefly stated, in the illustrated embodiment of
which is to be maintained in some de?nite opera
my invention I provide a controlled electric valve
tive relation with respect to another motor, it is
system for variably energizing the armature
desirable to insure that the output of the electric
winding of an electric motor to maintain a pre
valve apparatus is returned to a predetermined
determined speed relatlon between the motor and
value each time the system is deenergized so that
another motor which is not energized through
the initial energization of the load circuit is always
the same. In systems of this character employed 20 the electric valve means. ‘The control of the
electric valve means to effect the desired variable
for controlling the energization of one of a plu
energlzation is accomplished by means of motion
rality of motors to maintain the motors in de?nite
transmitting devices including a differential mo
speed relation by means of synchronous motion
tion transmitting device which is operatively con
transmitting devices driven by the motors and
operating to control the position of a movable 25 nected with the rotor of a phase shifting device
for controlling the excitation of the electric valve
element for varying the output of the electric
means. The connection between the rotor of the
valve means, it has been found that if the mov
differential signal device and the rotor of the
able element is positively driven in accordance
phase shifting device is accomplished by means
with ‘the relative positions of the movable ele
ments of the motion transmitting devices, uneven. 30 of a torque clutch which permits synchronous
movement of the differential device after the
operation of the regulating system results if the
rotor of the phase shifting device has reached
speed relation of the motors continues to depart
the limit of its movement. This provides for
from the desired relation after the movableele-s
smooth functioning of the control at the time the
ment of the valve controlling means has reached
the limit of its movement. In order to overcome 35 desired speed relation is again attained and oper
ating of the movable element of the phase shift“
this dimculty I provide a connection between the
ing device within its effective range is resumed.
motion transmitting devices and the movable ele
In order to insure that the initial output of the
ment of the tube controlling means which permits
' electric valve apparatus is always the same upon
the motion transmitting devices to remain in syn
chronism after the movable element of the con 40 energization of the anode-cathode circuit thereof,
1 provide means for automatically returning the
trol device has reached the limit of its travel. In
rotor of thc phase'shiiting device to a predeter
this way a continued temporary departure of the
mined position upon deenergization of the anode
desired relation between the movable elements
cathode circuit of the electric valve means and
and the motors after the movable element of the _
also provide means for preventing energization
tube controlling means has reached the limit of
of the anode-cathode circuit until the rotor has
its travel permits the motion transmitting devices
been returned to the predetermined position. In
to remain in synchronlsm and as soon as the speed
order to improve the smoothness of action of the
relation approaches that desired and the. motion
control system still further I provide an improved '
transmitting devices tend to rotate the movable
element of the controlling means in the opposite 50 anti-hunting circuit including a resistor-capacitor
combination responsive to voltages of the load
direction the control‘ is picked up smoothly as
circuit for modifying the excitation voltages ap»
contrasted with the sudden changes which occur
if the motion transmitting devices temporarily
plied to the electric valves. rthe anti-hunting
circuit includes a pair'of parallel resistors each
lose synchronism with the rotating elements of
of which is provided with a variable tap for vary“
the motors which are controlled.
2,411,745
ing the magnitude thereof so-that it is possible
to adjust independently the time constant ofthe
condenser circuit and the magnitude of the re
sistance included in the control circuit.
My invention will be better understood by ref
erence to the following description taken in con
nection with the accompanying drawing and its
_ scope will be pointed out in the appended claims
In the drawing, the single ?gure is a schematic
representation of one embodiment of my inven
tion.
‘
-
Referring now to the drawing, I have shown
my invention embodied in a controlled electric
valve system for variably energ’zing the armature
with the voltages of the phase terminals of the
threeephase stator winding 35 of a phase shift
ing device 36 having a three-phase rotor winding
31. The phase shifting device 38 is of a'type well
known in the art and is similar in mechanical
construction to a three-phase wound rotor in
duction motor. The circuit between the three
phase terminals of the stator winding 35 and the
respective control members 25 of valves I g, 20
and 2| is completed through current limiting re
sistors 38. Thev'neutral terminal of the stator
winding '35 is connected to the cathode bus 36
of the valves I9, 28 and 2! through a portion of
a resistor 39 determined by the positionof the
windings of a direct current motor 90 to maintain 15 slider 40. Resistor 39 and a parallel connected
a predetermined speed relation between the mo
resistor 4| form part of an anti-hunting circuit
tor Ill and another direct current motor i I which
which is operative to introduce by means of the
has the armature l2 thereof energized from a di
7 portion of resistor 39 included in the circuit of
rect current supply 13 through a suitable motor
the control members 25 a voltage dependent upon
starting and control circuit (not shown). The 20 changes in voltage across ‘the terminals of ar
direct current ‘motor ID has the terminals of the
mature id of the machine it. The anti-hunting
armature Id thereof connected in the direct cur
circuit includes a resistor 62 and capacitor 63
rent circuit of an electric valve recti?er illus
connected in series across the terminals of the
trated generally by numeral H5. The motors l0
armature It and a capacitor lit connected be
and ii each include a ?eld winding l5 energized 25 tween the common point of resistor 52 and yea
from a suitable source of direct current I1
pacitor t3 and the terminal of parallel resistors
through a variable resistance It.
39 and Eli remote from the cathode bus 34!. The
As mentioned above the armature winding of.
condenser M for a given voltage of the armature
I the motor to is energized from the direct current
it is charged to a predetermined value. Changes
circuit of an electric valve recti?er it. As illus 30 in the armature voltage result in a change in the
trated in the drawing the recti?er is a three
charge of the capacitor M and the charging cur
' phase half-wave system comprising three electric
rent ?owing through resistor 39 introduces a di
valves I9, 20 and 2i each preferably of the type
rect current bias voltage in the circuit of vcontrol
comprising a container enclosing an ionizabie me
members 25 which a?ects the conductivity of the
dium,_ such as a gas or vapor, and ‘within which 85 valves in a direction to oppose the change in ar
are mounted an anode 22, a cathode 23 and asso
mature voltage. The magnitude of the bias volt
ciated heater element 213, a control member or
age for a given current ?ow through resistor 39
grid 25 and a shield grid 26. The particular type
is controlled by the position of the slider all while
of valve illustrated~ is not essential to the present
the position of a short circuiting slider 85 on re
invention and any of the well known types of 4.0 sistor 4| determines the total resistance of the
controlled electric valves may be employed, if de
parallel resistance combination 39 and Ill to de
sired. The anodeecathode circuits of the electric
valves are energized from a three-phase alternat
‘
termine the time constant of the discharge cir-i
cult of the anti-hunting capacitor it. Capaci
ing current supply circuit 2? which energizes an
tor 43 cooperating with resistor 42 operates as
alternating current bus 28 under the control of a 45 ?lter to remove a portion of the ripple from the
manual switch '29. The anodes of the electric
voltage of the anti-hunting circuit. Capacitors
valves I 9, 20 and 2! are connected to the end ter
£511 are connected between the respectivecontrol
minals of a Y-connected secondary winding 3d
members 26 of electric valves 19, 2D and 2i and
of an anode transformer 3i having a delta-con
the cathode bus 34 and serve to minimize tran
nected primary winding 32 connected to the al 50 sient voltages on the control members and im
ternating current bus 28. The direct current cir
prove the controlling action thereof.
cuit of the recti?er is completed from the neu
As previously mentioned, the motor i0 is vari
tral connection 33 of the secondary winding 30
ably energized to operate at a speed dependent
upon the speed of the motor [I i. The arrange
to one armature terminal of motor Ill and from
the other armature terminal of the motor to the 55 merit for controlling the position of the rotor 37!
cathode bus 34 of the electric valves i9, 20 and
of phase shifting device 36 to accomplish this
26. As is well understood by those skilled in the
speed relation between motors in and M will now
art the three-phase recti?er circuit described
be described. A source of alternating current
above is effective to supply direct current to the
control voltage is derived from the alternating
armature of the motor In at a voltage dependent dd current bus 28 by means of a control transformer
upon the energization of the control members or
66 having a primary network it? comprising three
grids 25 of the electric valves.
phase windings provided with taps which may
_ The control circuit for energizing the control -
members 25 to e?ect Variable energization of the
be adjusted to provide the desired magnitude of
control voltage. The secondary network 48 pro
motor in will now be described. In the arrange 65 vides a source of energizing voltage for the rotor
ment illustrated the motor to is intended to op
Winding 31 of the phase shifting device 3%. The
erate at a ?xed ‘speed relation with respect to the
transformer is also provided with secondary
motor H as may be desired in many commercial
windings t9 and 5d. Winding 69 provides a
applications such. for example, as in the case of
source of energy for heating the cathode heaters
a cable making equipment where motor Hi, for
241 of electric valves 89, 20 and El and the sec
example, may be the reel driving motor and the
ondary d6 provides a source of voltage for en
motor it may be the ?yer motor or, in other
ergizing the rotor windings 5i and 5'2 of angular
words, the motor which controls the twist or
motion transmitting devices 53 and 56 respec
‘lay of the cable. The conductivities of the elec
tively. The devices 53 and 553 are provided with
tric valves lQ-Zl are controlled in accordance 75 three phase Y-connected stator windings 55 and
9,411,745
5
a as respectively with the phase terminals of stator
winding 55 connected with the phase terminals
valves I9, 20 and 2| are controlled by the movable
contacts 66 of an anode contactor 61 having an
of the three phase rotor winding 5.‘! of a differen
operating electromagnet 68 including an operat
tial motion transmitting device‘ 58 while phase
ing coil 69. The coil 68 is connected to be en
ergized from one phase of the transformer sec
ondary network ‘8 through a manually controlled
switch 10 and a pair of spaced’fixed contacts ‘H
terminals of the winding 56 are connected with
l ,the phase terminals of the polyphase stator
winding 59 of the differential motion transmit- ,
the stator terminals of the differential device and -
which are bridged by‘a conducting member 12
when the phase shifting device is in the position
are of such a rating that they take a. leading
of minimum output of the electric valves. The
tingdevice 58. Capacitors 60 are connecte'dacross
cooperating contacts ‘H and 12 also provide a
excitation current equal to the lagging excitation
mechanical 'stop for the rotor of the phase shift
current required by the differential device with
ing circuit. A mechanical stop 13 is provided
the result that the exciting current which must
to limit the movement of the rotor winding 37
be supplied to the differential by the device 53
for example, is equal only to the power compo 15 in the opposite direction. It is apparent that
these stops may be adjusted in angular position
nent of the current which is in general only
to determine the minimum and maximum output
a small portion of the total excitation current.
of the electric valve means. A variable contact
As illustrated in the drawing, the rotor wind
14 actuated by the relay 68 completes a circuit
ing SI of device 53 is coupled to the shaft of motor
ill by means of suitable gearing designated by 20 in parallel with the contacts ‘H to provide a hold
ing circuit for the coil 68 after it has moved .the
the numeral 6!, and the rotor 52 of device 5| is
mechanically coupled to the shaft of motor I I by
suitable gearing. 62. This gearing is arranged so 7
contacts 65 to closed position.
’
The rotor 31 of the phase shifting device 38 has
that the speed of rotation of windings ii and 52
are equal when the desired speed relation be
tween the motor ill and the motor It exists. As
is well understood the Selsyn system including
an inherent tendency to rotate in a direction to
devices 53, 5B and 58 operate to produce a torque
mum output when the anode-cathode circuits of
electric valves are deenergized, I provide means
on the rotor 5? dependent on the displacement
reduce the output of the electric valves i9, 20 and
ii. In order to utilize this tendency to restore
the phase shifting device to the position of mini
between windings 5i and 52. For example, if 30 for loading electrically the stator winding with
impedance elements such as resistors 15 in re
windings 5i and 52 are in equilibrium position
sponse to opening movement of the contacts 66. '
no torque is produced on winding 51. However,
As illustrated in the drawing, this is accomplished
a change in speed of one of the motors from the
by means of a switching device ‘it having mov
desired speed with respect to the other motor
causes a relative displacement of the windings 5i 33 able contacts Tl for connecting one of the re
and 52 and torque is produced on winding 5i
sistance elements 15 in circuit between each pair
of terminals of ‘the stator winding 35 of the de-.
dependent on the magnitude and direction of the
vice 36. "The device 76 is provided with an actu
relative displacement of the windings 5i and 52.
ating coil ll'a connected to be energized from one
As illustrated in the drawing, the rotor winding
57 is mechanically coupled by means of a shaft 40 phase of the control power supply transformer
secondary 45 through a circuit including a mov
63 to a torque clutch illustrated schematically at
able contact 18 on the anode contactor 61. From
64 which has the output shaft 65 thereof con
an inspection of the circuit of coil 11 it is seen
nected with the rotor of the phase shifting selsyn
that it is electrically connected with the trans
36. The torque coupling provides what under
normal operation is a positive drive of the rotor 45 former secondary winding 48 whenever the anode
contacts 88 are closed. in this way the resistors
of the phase shifting device 36 but which per
‘15 are automatically disconnected from the stator
mits continued rotation of the differential Selsyn
winding of the phase shifting device 36 when the
after the phase shifting rotor has reached the
anode leads of the electric valves i9, 20 and 2|
limit of- its travel. This arrangement allows the
differential Selysn to continue to rotate in the 60 are closed by closure of contacts 66. When the
rotor 31 of the device 86 is energized from the
differential selsyn to continue to rotate in the
supply circuit 28 this loading of the stator in
event that the departure from the desired speed
creases the torque tending to rotate the phase
relationship between machines Ill and H is not
shifting device to the position or minimum out?
immediately corrected by control of the electric
valves I9 to 2| before the winding 31 reaches one 55 put of the electric valves and to maintain the
same in that position with the cooperating con
of its extreme positions.
tacts ‘H and “I2 operating as a mechanical stop
With the motor control system illustrated it is
. against which the rotor is held.
desired that the electric valves 19, 20 and 2|
Although the operatic/n of the various elements
have their anode-cathode circuits energized and
that the control circuit therefor be adjusted so 60 of the system described above has been described
during the description, it is believed that the fea
that the output voltage is insu?icientto rotate
tures and advantages of the present invention will
the reel motor l0 until after the motor ‘I! has
been started. Preferably the minimum output‘
be more apparent from a brief consideration of
the operation of the system as a whole. Let it be
of the valves is su'?lcient to produce considerable
torque in the reel but insu?icient to rotate it. To 65 assumed that switches 29 and '16 are open and
that both motors lo and il are-at standstill. If
this end means are provided for insuring that the
rotor 3101’ the phase shifting device 36 is re
it is desired to start the system, switch 28 is ?rst
turned to the position of minimum output of the
closed energizing transformer 46 and the rotor
winding of phase shifting device 36. The Selsyns
electric valves when the anode-cathode circuits
of the electric valves are deenergized and for pre 70 53 and 54 are also energized and the cathode
heater elements of the electric valves l9, 2G and
venting the energization of the anode-cathode
21 are energized. The contacts ‘H are normally
circuits until the rotor has been returned to the
position corresponding to minimum output volt
closed and resistors 15 are thereby connected
age of the electric valve recti?er. Referring
across the terminals of the stator windings 35 of
again to the drawing, the anode circuit of the 75 the phase shifting device 38, thus increasing the
acreage
torque produced on the rotor to insure that it is
rotated to the position of minimum output and
that movable conact‘ I2 is closed on contact Ii.
After the cathode heater elements are at oper
ating temperature, preferably insured by a time
delay relay (not shown) having a contact in cir
dependent upon the voltage of motor it. Any
change in this voltage produces a change in the
condenser charge at a rate dependent upon the
time constant of the condenser resistor circuit.
The resistor 39 is. connected in the circuit of the
control members 25 so that the polarity of the
cuit with switch 7@, the switch ‘ill is closed and
voltage caused by a change in the condenser
coil 69 of relay 6% is energized from one phase
charge is in a direction to'oppose the change in
of winding 458 through the contacts ll and'l2- of
voltage of the armature machine i0 causing the
the limit switch associated with the phase shift 10 change in the condenser charge. In this way
ing device 36. As soon as relay 68 picks up, con
overshooting of the system is prevented and a
tact 18 is- closed to complete a circuit for coil
smooth regulating action obtained. The slider 65
‘Ha to operate contacts ill to open circuit position
controls the magnitude of resistance in circuit
and disconnect one terminal of each of the re- I
with condenser Lid and in this way controls the
sistors ‘l5 from the stator winding 35. The con
time constant of the condenser circuit. The
tacts 66 in the anode leads are closed and the
slider d0 controls the portion of resistor- 39 in
contact ‘M in parallel with contacts ‘H and I2 is
the control circuit and in this way controls the
magnitude of the anti-hunting voltage for a given
closed to complete a holding" circuit for the coil
69. The tube circuit is now in operating condi
current through resistance element 39. Con
tion and will function to impress a variable volt 20 denser d3 cooperates with resistor (32 to provide a
age on the armature winding of motor to de
?lter to remove some of the ripple from the anti
pendent upon the relative position of windings 5i
hunting voltage. The tendency of the regulat
and 52 of the devices 53 and 56 respectively. The
ing system to hunt may also be decreased by the
next step in the operation is the starting of the
introduction of-reduction gearing between the
motor i! which is brought up to operating speed
rotor 57 and rotor 31’ of the phase shifting device.
The gearing may be incorporated in the clutch
by any suitable starting circuit (not shown). As
unit 6d if desired.
motor it starts to rotate winding 52 will move
with respect to winding 5! and in this way pro
When it is desired to shut down the motors,
motor H is ?rst deenergized and brought to a
duce a torque on winding 57] which is transmitted
to rotate the movable element of phase shifting 30 standstill by dynamic braking if desired and
with the control circuit for motor iii functioning
device 36 in a direction to increase the output
in this way the motor ill follows motor it to
voltage of the electric valve recti?er and in this
standstill at which time switch W is opened.
1 way cause the reel motor iii to- start rotating.
Upon opening of the control switch Ill coil 89 of
The torque imparted to the winding 51 and its
the anode contactor operating relay 68 is opened
associated structure is always in a direction to
to deenergize the anode-cathode circuits of the
rotate the movable element 31 in a direction to
‘effect the change in the ‘impressed voltage on
electric valves i9, 20 and 2i. Contact 18 is also
opened to deenergize the winding Ila of the relay
the armature of motor Iii necessary to change its
It thus allowing contact II to close and connect
speed in the proper manner to bring the ele
ments ‘5i and 52 into the correspondence and in
resistors 75 across the stator winding 35 of the
phase shifting device 36. As described above this
this way to maintain the desired speed relation
between motors l8 and H.
'
insures that the winding 37 is returned to the
position of minimum output against the stops
‘ Inasmuch as movement of the rotor 37 of the
provided by contacts ‘H and 72 and places the
phase shifting device 36 to one of its extreme
system in position to be again. operated. If the
positions may fail temporarily to restore the de
shutdown is for a long period the contact 29 may
sired positional relation between the. movable
be opened and the system completely deenergized. elements of motors H3 and H, it is desirable to
provide for relative movement between the wind
While I have described what I at present con
ing El of the differential motion transmitting de-T
sider the preferred embodiment of my invention,
it will be obvious to. those skilled in the art that
vice 58 and the rotor 37. To this end the torque
clutch 6d interposed between the winding 57 and
various changes and modi?cations may be made
the winding 37 permits relative movement of
without departing from my invention, and I.
these windings when the torque required to ro
therefore, aim» in the appended claims to cover
all such changes and modi?cations as fall within
tate winding GI exceeds a certain value. The
the true spirit and scope of my invention.
clutch is adjusted so that the windings 37 and
57 are maintained in fixed relation to each other
What I claim as new and desire to secure by
as long as winding 37 is not against the stops
Letters Patent of the United States is:
provided by contacts ‘H and 72 at one limit of
1. In combination, a supply circuit, a load cir
travel and the mechanical stop ‘l3 at- the other
cuit, electric translating apparatus interconnect
limit of travel. In this way the system includ 60 ing said circuits including electric valve means
ing motion transmitting devices 53, 5d and 58 are
having a control member for controlling the con
allowed to remain in synchronous relation so that r,
as the elements of the motors ill and I I approach
ductivity thereof, phase shifting means including
the desired relationship and the phase shifting
control member to thereby variably energize said
a movable element for variably energizing said
device 3‘? is to be moved away from its extreme 65 load circuit, means for stopping said movable ele
ment at a predetermined limit of travel, means
position the devices 53, 5d and 58 are functioning
smoothly and the winding ill is not operated 11n
evenly as it would tend to if it were resynchro
forimparting a driving force to said movable
element ,dependent upon the energization of said
load circuit, and a mechanical connection be
ni’zing after having been out of step with the
remainder of the motion transmitting system.
70 tween said last mentioned means and the mov
In order to prevent hunting of the regulating
able element of said phase shifting means nor
system the circuit including resistor d2, capaci
mally providing a positive driving connection
tor M and parallel resistors 39 and d! are con
therebetween but permitting said last mentioned
nected across the armature terminals of the m0
means to continue movement in the same direc
tor ill. The capacitor tilt tends to have a charge 75 tion required to move said movable element to
'
2,411,745
10
said limit of travel after the movable element of.
' cal connection normally providing a positive
said phase shifting device has been stopped at
drive but permitting relative movement between
the movable element of said .phase shifting
the limit of its travel‘
2. A supply circuit, a dynamo-electric machine,
electric translating. apparatus interconnecting
means and the movable element of said motion
transmitting system when thegnovable element
said circuit and said machine including electric
of said phase shifting means reaches a limit of
valve means having acontrol electrode, phase.
its travel.
‘
_
shifting means including a movable element for
4. A supply circuit; a dynamo-electric machine,
controlling the conductivity of said electric valve
electric translating apparatus interconnecting
means, a self-synchronous motion transmitting 10 said circuit and said machine including electric
system for producing a torque dependent upon
valve means having a control electrode, a control
the operation of said dynamo-electric machine,
circuit for controlling the energization of said
and a torque clutch interposed between a mov
control electrode including a phase shifting de
able element of said motion transmitting system
vice having a rotatable element, means for posi
and the movable element of said phase shifting 15 tioning said movable element in accordance With
device to permit said movable element of said
the operation of the dynamo-electric machine
motion transmitting system to remain in syn
comprising a self-synchronous motion transmitchronism after the movable element of said phase
ting system including a differential motion trans
shifting device reaches the limit-of its travel.
mitting device having a movable element, me~
3. A supply circuit, a dynamo-electric machine, 20 chanical means interconnecting the movable ele
electric translating apparatus interconnecting
ment of said motion transmitting system and the
said circuit and said machine including electric
rotatable element of said phase- shifting device
valve means havinga control electrode, phase
comprising‘ means for normally driving the ro
shifting means for controlling the conductivity
tatable element of said phase shifting device in
of said electric valve means including a movable 25 fixed relation to the movable element of said
element movable between predetermined limits to
motion transmitting system, said last mentioned
vary the conductivity of said electric valve means
means providing for relative movement of said
between a maximum and a minimum, a self
rotatable member and said movable member
synchronous motion transmitting system for pro
when the torque required to rotate said rotatable
ducing a torque dependent upon the operation of 30 element exceeds a predetermined ‘value to permit
said dynamo-electric machine, mechanical means
the movable element of said motion transmitting
interconnecting the movable element of said mo
system to remain in synchronism.
tion transmitting system and the movable ele
ment of said phase shifting means, said mechani
ELMO E. MOYER.
'
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