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Патент USA US2407072

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Sept. 3, 1946!
'
w. N. GITTINGS ETAL
ELECTRIC
CONTROL
2,407,072
SYSTEM‘
Filed 0st,. 24, 1944' '
7
v
4 Sheets-Sheet 1
Fig. la.
2
PHASE SHIF TEH
P07E/VTML
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Inventors:
William N. Sittings}
Amos“ W. Bateman,
by
Thelr" Attorney.
Sept. 3; 1945-
w. N. GITTINGS ET AL
J 2,407,072
ELECTRIC CONTROL SYSTEM
Filed Oct. 24, 1944
4 Sheets-Sheet 2
.1
FHA SE SH/F7'EH
+ 67
—68
69
74
Inventors:
WiHiam N.Gittings,
Amos W. Bate an,
by
Thai
Atto r‘n ey.
Sept 3', 1946‘
w. N. GITTINGS. ETAL
‘
2,407,072 -
ELECTRIC‘ CONTROL SYSTEM
'
Filed Oct. 24', 1944]
4 Sheets-Sheet 3
Pi .Saz
Inventor's:
William N. Gitt'mgs,
ArnOs W. Bateman,
by
’
-
T heir‘ Attorney.
v Sept. 3, 1946.
'
'w. N. GITTINGS ET AL
‘2,407,672
ELECTRIC CONTROL SYSTEM
Filed Oct. 24, 1944
‘ F‘i
4 Sheets-Sheet 4
3b.
L010
Inventors:
William N. Sittings, ‘
Amos W. Bateman, ’
by
Then”- Attbr‘ney
Patented Sept. 3, 1946
2,407,072
UNITED STATES PATENT OFFICE
2,407,072
ELECTRIC CONTROL SYSTEM
William N. Gittings, Oakmont, and Amos W.
Bateman, Yeadon, Pa, assignors to General
Electric Company, a corporation of New York
Application October 24, 1944, Serial No. 560,161
32 Claims. (Cl. 171--97)
1
2
Our invention relates to electric control sys
tems and more particularly to electric control and
It is a further object of our invention to provide
new and improved fault control and protective
regulating systems for power conversion systems.
means in an electronic conversion system.
In order to illustrate our invention, we will de
scribe suitable apparatus for carrying it into effect
in an electronic conversion system but it will, of
course, be understood that our invention in its
broader aspects is not limited to the particular
Our invention will be better understood from
the following description taken in connection with
the accompanying drawings, and its scope will be
pointed out in the: appended claims.
In the accompanying drawings, Fig. la and Fig.
1b are, respectively, a ?rst and second section of
application described but is gene-rally applicable,
in whole or in part, to various systems- of control 10 a diagrammatic illustration of one embodiment
of our invention in an electronic conversion sys
or regulation in other electric systems.
tem of the dual conversion type; Fig. 2 is an ex
A type of electronic power‘ conversion equip
planatory diagram, and Fig. 3a and Fig. 3b are,
ment to which our present invention is applicable
respectively, a ?rst and second section of a modi?
is that type sometimes known in the art as a dual
conversion system wherein the power from an al 15 cation of the invention illustrated in Fig. 1a and
ternating current supply circuit is recti?ed by a
Fig. lb and illustrates the control of a plurality
of electronic conversion units.
Referring now to Figs. 1a and 1b‘, we have in
dicated an electronic power conversion system
tube inverters which, in turn, deliver power of
the same frequency as the sup-ply circuit, or of 20 in a simple schematic. form since the particular
arrangement and features of the electronic power
a different frequency, to an alternating current
circuits per se, as distinguished from switch
load circuit. Such apparatus may be used to
ing and control circuits, do not form a part of
interconnect two electrical systems: and may be
our invention. A satisfactory arrangement of
classi?ed as a system tie, a frequency changer, or
a direct current transmission system, depending 25 the electronic power circuits for commercial pur
poses in described and claimed in an application
upon the: principal function performed by the
conversion apparatus.
of August Schmidt, Jr., Serial No. 539,939, ?led
group of tube recti?ers, transmitted as direct cur
rent over a direct current loop to a group of
June 12, 1944, and assigned to the assignee of
the present application.
In the system as illustrated in Figs. la and 1b,
possible to adjust the ?ow of power to any desired 30
In such systems it is usually required that the
power flow be reversible at will and that it be
value in either direction. Thus, various regular -
We have shown one alternating current system I
ing and control means including selective control
of dynamo-electric machines and switchgear are
involved in carrying out our invention.
machine 2. Such a system may be taken as repre
It is an object of our invention to provide a new -
and improved electric control and regulating sys
"em.
connected to» be energized by a dynamo-electric
sentative of a public utility 60 cycle system which
supplies power to ‘an industrial customer.
An
industrial load, indicated by the rectangular out
line 3, is connected to be energized from a supply
It is another object of our invention to provide
circuit 4 which, in turn, is connected through a
a new and improved regulating system for elec
switch 3’ to the system I. It may also be as
tronic power conversion apparatus interconnect
sumed that the industrial customer has; local 60
ing two alternating current systems which will en
cycle generators, indicated by generator 5, which
able the power interchanged between such sys
also feed power to the circuit 4 to assist in sup
tems to be controlled at any desired value for
plying power to load 3. A second alternating cur
either direction of power ?ow.
It is another object of our invention to provide 45 rent circuit 6 is shown at the opposite end of the
system with a dynamo-electric generator ‘I and
new and improved control and regulating means
an industrial load 8. For purposes of illustra
for dynamoelectric machines.
tion, the circuit 6 and the connected apparatus
It is another object of our invention to provide
may be taken to represent a 25 cycle alternating
new and improved regulating means in an electric
current system of an industrial customer. The
control and regulating system.
two alternating current systems, namely the as
It is another object of our invention to pro
sumed 60 cycle system I and the assumed 25
vide a new and improved control system for a plu
rality of electronic power conversion units op
cycle system 6, are interconnected by electronic
erated for interchange of power between two al
power conversion equipment, indicated generally
ternating current systems.
55 by the numeral 9, which is arranged to transfer
2,407,072
3
4
power in either direction between the two alter
nating current systems. I and 6.
The electronic power conversion apparatus 9 is
interconnected with the. alternating current sys
tem I through transforming means IE, bus II and
suitable circuit interrupting means I2, and is
similarly connected to circuit 6 through trans
forming means- I3, bus I4 and suitable ‘circuit
insulating transformer 40 and the grid circuit 34
is supplied through a peaker transformer 4| and
interrupting means I5.
includes a bias means 42. An ignitor short-cir
cuiting switch 43 having an operating coil 44 is
provided to short-circuit the ignitor transform
ers for the purpose and in the manner to be
described later. A suitable form of ignitor and
grid control circuits, in accordance with the sche
matic arrangement disclosed, is described and
‘
The electronic conversion apparatus 9 com
prises two converter tube groups I6 and I ‘I shown
in a very simple form and each comprising a
group of six tubes connected in a three-phase
double-way (full wave) circuit. A particular ar
rangement of transformers and tube groups suit~
able for a commercial arrangement is shown and
described in the above-identi?ed Schmidt appli
cation. In the simple arrangement illustrated
herein, the tube group I6 comprises siX tubes I8
in which tubes 180 degrees apart in phase po—
sition are mounted back-to-back with the cathode
of the upper tube connected to the anode of the
tube below it, as viewed in the drawings. Simi
larly, the tube group ll comprises six tubes I9
connected in a three-phase double-way circuit in
which the tubes 180 degrees apart in phase po
sition are mountedback-to-back. We have il
lustrated the tubes as being of the ignitron type
although our invention is not limited to ap
10 claimed in an application of B. D. Bedford, S.
No. 539,941, ?led June 12‘, 1944, and assigned
to the assignee of the present application. The
excitation circuits are arranged to be supplied
from a source of alternating current which is cor
15 related in phase and frequency with the alter
nating current circuit associated with tube group
I6. As illustrated, the excitation circuit means
3'6 is connected-to be energized from the circuit
4 through circuit 45 having therein a suitable
20 switch 46 and transformer 41. The device 36 in
cludes a phase shifting means which is controlled
in accordance with the differential voltage be
tween an adjustable ?xed component of voltage
introduced from a resistor 48 and a variable com
25 ponent of voltage depending upon an electrical
condition of tube group I6 operating either as a
recti?er or an inverter. The variable component
of voltage is introduced in the input circuit of
device 36 by resistor 49 which is connected by
plications involving tubes of any particular type. 30 the switch 50 to be energized in accordance with
Each of the several tubes l 8 of group I6, as illus
trated, is provided with an anode 20, a mercury
pool cathode 2|, an immersion ignitor or are
initiating member 22, a holding anode 23 and a
control electrode or grid 24 to determine the 35
instant of conduction in each tube in the proper
an electrical condition of the tube group I6 op
erating either as a recti?er or inverter, as indi
cated by the R and I positions of switch 50. A
shift in the phase relation between the various
control electrodes and the associated anodes is
utilized to obtain the desired power flow be
sequence for recti?cation or inversion. Similar
tween circuits I and 6 in the manner to be de
ly, the several tubes IQ of tube group I‘! are pro
scribed later. A suitable and commercially sat
vided with an anode 25, a cathode 26, an immer
isfactory form of phase shifter and control ap
sion-ignitor or are initiating member 21, a hold 40 paratus, in accordance with the schematic form
ing anode 28 and a control electrode or grid 23.
illustrated, is of the type described and claimed
The direct current terminals of the tube groups
in an application of B. D. Bedford, Serial No.
I6 and I1 are interconnected by a direct cur
539,942, ?led June 12, 1944, and assigned to the
rent loop circuit 3!! having interposed therein a
assignee of the present application. In the form
direct current reactor 3| to suppress voltage rip 45 of phase shifter disclosed in this Bedford appli
ple in the direct current circuit.
cation a voltage component variable in accord
Each of the tube groups is furnished with suit
ance with an electrical condition of the tube
able excitation circuits for each ignitor, holding
group [6 or H, such as the current input there
anode, and control electrode but since the par
to, constitutes the variable signal voltage and
ticular form or details of the excitation circuits 50 is compared with an adjustable reference volt
do not form a part Ofour invention, we have il~
age which is indicated in the accompanying
lustrated these circuits in a very schematic form.
drawings by the voltage drop across the resistor
Thus each tube I8 of conversion unit I6 would
48. This reference voltage may be obtained from
be provided with excitation circuits indicated by
a well known form of three phase induction reg
the cathode-ignitor circuit 32, the holding anode 55 ulator 5| connected to be energized from an in
circuit 33 and the grid circuit 34 connected to
the several electrodes of the lower right-hand
tube I 8 of group I6, as viewed in the drawings.
Unidirectional conducting devices 35 and 35' are
connected in circuit with ignitors 22 and 21, re
put circuit 52 and having its usual series and
degrees.
by the circuits 32’, 33’ and 34’, respectively, lead
shunt windings connected in a manner to pro
vide an output voltage across its output circuit
53 which is variable in magnitude in accordance
with the position of its rotatable element 54.
spectively, in a conventional manner. These cir
The output circuit 53 is connected to energize a
cuits are arranged to be energized from suitable
transformer ‘55 having a primary winding 56 and
excitation means indicated by the rectangular
two secondary windings 51 and 58. The volt
symbol 36 with a notation “phase shifter” which
age of secondary winding 51 is recti?ed by a
would include the necessary transformers, reac 65 suitable recti?er 59 and impressed across the
tors and other elements utilized in excitation
resistor 48.
circuits of this type. The ignitor circuit 32 com
Similarly to tube group [6, each tube I9 of
prises an output transformer 31 having a pair of
tube group I’! is provided with ignitor, holding
secondary windings 38 which are connected, re-_
spectively, to tubes [8 displaced 180 electrical 70 anode and grid control excitation as indicated
Similarly, the holding anode circuits
ing from the excitation means 36’. This excita
tion means is energized from the bus I4, the alter
nating current circuit associated with tube group
holding anode circuit 33 is. supplied through an 75 I1, through a transformer 6|]. A switch 43’ hav
33 and grid circuits 34 are Supplied from an out
put transformer 39 having a pair of secondary
windings for the associated pair of tubes. The
5
2,407,072
ing an operating coil 44' is arranged for short
circuiting the ignitor transformer 31' in the same
manner as has been illustrated for ignitor trans
former 37 of tube group iii. The signal voltage,
variable in accordance with an electrical con
dition of the tube group IT, is introduced into
the phase shifter ‘by resistor 49' and switch 56’.
An adjustable reference component of voltage
6
tion and speed of rotation of rotor 54. Hence,
a reversible polarity direct current generator 69
is utilized to energize the armature winding of
motor 6!. Although various types of generators
having the proper characteristics may be used,
We have found it preferable to use a generator
of the armature reaction excited type, known in
the art as an amplidyne generator, and described
is derived from secondary winding 58 through
and claimed in U. S. Letters Patent No. 2,227,992,
recti?er 59' having its direct current terminal
granted June as, 1939, upon an application of
connected across resistor 48'.
M. A. Edwards and E‘. F. W. Alexanderson. The
Although we have illustrated schematically a
amplidyne generator is a preferred form because
particular form of means for effecting phase
its low excitation requirements permit the use
shift by adjusting a reference voltage correlated
of relay and control switch contacts directly in
with a variable component so that phase shift 15 its ?eld circuits owing to the fact that the con
in one direction or the other is effected, depend
trol ?eld currents may be as low as 0.1 ampere for
ing upon the resultant between the two voltage
a generator terminal voltage of 300 volts and
components, it will be evident to those skilled in
the resistance of the ?eld circuits is low com
the art that our invention in its broader aspects
pared with that of conventional generator ?eld
ray be carried out in response to a variable ele 20 circuits. The use of a reversible voltage gen
ment which effects a phase shift directly or indi
orator to energize the motor 5i permits the motor
rectly between two voltages as a result of the
to be reversed without reversing contactors; per
movement of a movable element in response to
mits easy adjustment of the motor armature
the condition to be regulated.
voltage magnitudes; permits the use of simpli
As fully explained in the above—identi?ed Bed
?ed control circuits; and provides inherent dy
ford application S. No. 539,942, the desired load
namic braking. The generator 69 has a pair of
on the electronic conversion unit, in accordance
short circuit brushes ‘ill for providing the main
with the means herein illustrated, is set by the
armature reaction excitation of the machine and
induction regulator 55 in accordance with the
a pair of load brushes 1i and
which are'in
reference voltage obtained across resistor 48 or quadrature relation with the short circuit brushes
48' which is proportional to the rotation of rotor
ll). The generator is provided with a compen
54. Generally speaking, if unit it is operating
sating winding "l3 in circuit with the load circuit
as a recti?er, unit I‘! will then be operating as an
brushes ‘ii and ‘E2 which substantially neutral
inverter. The grids of tubes !8 of the recti?er
izes the armature reaction of the generator along
will then be advanced from a predetermined
the axis of brushes ‘ii and 12. The load brushes
lagging phase position toward an in-phase or
ii and
are connected to the armature brushes
actually to an in-phase position to obtain max
and ill of motor 6i. The amplidyne gener~
imum power flow from circuit l to circuit 6.
ator is provided with three other ?eld windings
At the same time, the grids of the inverter tub-es
in addition to the compensating ?eld winding
59 will be operated in an advance position from
56. Two of these ?eld windings W5 and '55 may
a predetermined minimum advance position for
be referred to as control ?eld windings and the
inverter operation to a greater advance position
remaining ?eld winding ‘is is used as an anti
to maintain the desired commutating angle re
hunt and residual voltage killing ?eld winding
quired for deionization. For reverse power flow,
and is connected in shunt to the armature wind~
the tube group I‘! would be similarly operated as 45 ing through an adjustable resistor ‘H. The polar
a recti?er and the tube group‘ I6 would then be
ities of the ?eld windings are such that with
operated as an inverter.
In Fig. 2 we have shown a simple diagram
current flowing from left to right of the ?eld
winding, the right~hand load brush ‘ii is assumed
which illustrates, in a general way, the power
to be positive with respect to the left-hand brush
flow in the conversion system. Rotation of the 50 l2. When brush 'H is positive, the motor 6i is
rotor 54 from A to B or from C to D represents
assumed to. be rotated in the direction which
increase in power flow from zero to maximum for
causes the induction regulator rotor 5% to in
either direction of power flow as indicated.
crease the power ?ow from the circuit i to the
In accordance with our invention, we provide
circuit 6. For ease of identi?cation, we have
an electric control and regulating means which 55 heretofore referred to circuit ! as a 60 cycle sys
effects control of the power ?ow in the electronic
tem and circuit 55 as a 25 cycle system. In this
conversion system in either direction. In ac
event, tube group it will be operating as a recti
cordance with the illustrated embodiment of Figs.
?er and tube group ll as an inverter. To obtain
la and lb, we provide a direct current motor (5|
an increase in power flow from the 25 cycle sys
for operating‘ the rotor 54 through a suitable
cycle system, the rotation of the
60 tern to the
shaft 52 and suitable gearing 63 which, in turn,
motor $5 is reversed by having
current in
is connected through. a suitable shaft 64 to the
the generator ?eld. ‘ill or it? flow from right to
rotatable element 54 of the induction regulator
left. Control ?eld
is used only with a “de
5!. Between the motor 6! and shaft 62 we have
mand load” regulator
and control ?eld ‘M is
found it to be desirable to utilize: a high ratio 65 used with either a manual control is or with a
gearing £35 in order to reduce the speed ratio
“watt regulator" control 83, all to be described
between the motor and the rotor 54. The motor
presently. The control ?elds
and ‘it have a
5| is provided with load brushes 6B and 61 and
common terminal 84 which is connected to a
a ?eld winding 58 which is separately energized
mid-voltage or neutral tap es of a suitable source
from a constant source of voltage indicated by
of direct current such as a battery 83, although
the plus and minus signs. With this arrange 70
it
will be obvious that conventional forms of
ment the magnitude and polarity of the voltage
midtapped recti?ers could be used without de
impressed upon the armature brushes 56 and
parting from our invention in its broader as
6'! will determine the direction and speed of
pects. The other ends of the ?eld windings 1!;
rotation of motor GI and consequently the direc 75 and '55 are connected through control contacts to
2,407,072
7
be described presently to either end of the source
83 by means of an auxiliary control bus 84 so
8
recti?ers I09 and H0, which are poled oppositely
with respect to current ?ow from the midtap 02
of battery 83 so that in combination with their
associated limit switches the ?eld windings ‘I4
and ‘I5 are blocked against current flow which
Cam operated position switches 85, 86, 81 and
would run the rotor 54 past either limit of its
88 are operated from the shaft 62 of the motor GI
travel.
in order to provide the desired control relative
An auxiliary relay 85a having an operating coil
to the position of the rotor 54 of the induction
85b and three sets of contacts III, H2 and H3
regulator 5|. Position switch 85 includes a suit
ably shaped cam member 89, switch contacts 90, 10 is associated with and controlled by position
switch 85 so that the relay contacts are picked
switch biasing means 9I and contact operating
up for power ?ow from the 60 cycle system to the
means 92 which may take the form of a rod posi
25 cycle system, or from position A to position B
tioned to engage the operating surface of cam 89.
in Fig. 2. Similarly, an auxiliary relay I I4 having
The surface of cam 89 is so designed that contacts
an operating coil H5 and three sets of contacts
90 will be closed for motion of motor (H for sub
I I8, I I1 and H8 is associated with and controlled
stantially 165 mechanical degrees in a clockwise
by position switch 88 so that the relay contacts are
direction from a substantially twelve o’clock posi
picked up for power flow from the 25 cycle system
tion or Zero position corresponding to point A of
to the 60 cycle system, or from position C to D
Fig. 2 to, say, a ?ve-thirty position corresponding
in Fig. 2. Position switches 85 and 86 have their
to point X of Fig. 2. For the remainder of the
respective contacts 90 and 94 both open for a
circumference of the cam 89, contacts 90 are in
small portion of travel by the rotor 54 at the zero
the open position. During this clockwise move
power flow position as indicated between A and C,
ment of cam 89, power flow of the conversion
Fig. 2. At the zero position of rotor 54, there
system is assumed to be effected from the 60 cycle
system (circuit I) to the 25 cycle system (circuit 25 fore, both auxiliary relays I09 and H4 are
dropped out and all the contacts of the respective
6) . Position switch 86 similarly includes a suit
relays are in the open position. The use of the
ably shaped cam 93, switch contacts 94, switch
auxiliary relays 85a and H4 will be described
biasing means 95 and a contact operating means
later.
98. The surface of cam 93 is so designed that
The circuit interrupting device I2 is provided
contacts 94 will be closed for motion of motor SI 30
with any suitable circuit closing means H9 and
for substantially 165 degrees in a counterclock
circuit opening means I20. The circuit opening
wise direction from a substantially twelve o’clock
means I20 may be made responsive to overcur
position, or zero position, corresponding to point
rent conditions of the alternating current circuit
C of Fig. 2 to a six-thirty position corresponding
of the conversion unit IS in a conventional man
to point Y of Fig. 2. For the remainder of the
ner but, in accordance with our invention, we
circumference of cam 93, the contacts 94 are in
provide an additional circuit I2I for energiza-tion
the open position. Position switch 81 is a limit
in response to special fault conditions to be de
switch and includes a cam 91, switch contacts 98,
scribed later. The circuit interrupting device I2
switch biasing means 99 and a contact operating
means I00. The contacts 98 are arranged to be 40 is also provided with auxiliary circuit controlling
contacts I22, I23 and I24 which are shown, for
closed for a counterclockwise motion of motor BI
the open position of the circuit interrupting de
beginning from a substantially ?ve o’clock posi
vice I2, with contacts I22 and I24 open, and con
tion corresponding to point B of Fig. 2 to a five
tacts I23 closed. In order to simplify the draw
thirty position approached from. the counter
clockwise direction corresponding to point X of ? ings, each of the contacts I22, I23 and I24 may
be considered to represent two contacts in series,
Fig. 2. In other words, contacts 98 are closed at
one contact for the 60 cycle end as shown and
all times except when the rotor 54 reaches the
one corresponding contact for the circuit inter
end of its travel in the 60 to 25 cycle power ?ow
rupter I5 of the 25 cycle end.
direction (clockwise) at which point the contacts
98 open. Position switch 88 is also a limit switch 50 The rotor 54 of the induction regulator 5| is al
ways in the position represented for zero power
and includes a cam IOI, switch contacts I02,
flow at the time the 60 cycle and 25 cycle circuit
switch biasing means I03 and a contact operat
interrupts are closed. In the open position of
ing means I04. 'Ilhe contacts I02 are arranged
circuit interrupters I2 and I5, as illustrated,
to be closed for a clockwise motion of motor 6|
which would also result if the circuit interrupters
beginning from a substantially seven o’clock po
were tripped while the conversion apparatus was
sition corresponding to point D of Fig. 2 to a six
carrying load, the rotor 54 is automatically re
thirty position approached from a clockwise di
turned to the zero position corresponding to
rection and corresponding to point Y of Fig. 2.
points A to C of Fig. 2 for zero power ?ow. This
In other Words, contacts I02 are closed at all
is accomplished by the auxiliary contacts I23 of
times except when rotor 54 reaches the end of its
circuit interrupter I2 which connects the control
intended travel in the 25 to 60 cycle power ?ow
?eld winding ‘I4, through contacts III or H6 of
direction (counterclockwise) at which point the
auxiliary relays 85a or 5 I4, to the polarity of bat
contacts I02 open.
tery 83 which causes the motor BI to drive rotor
Indication of the position of the rotor 54 is
obtained by mounting a Selsyn transmitter I05 on C: .UT 54 towards its zero power ?ow position. As the
rotor 54 arrives at a position corresponding to
the shaft 62 and connecting the output of the
point A or C of Fig. 2, the relay 85a or H4 is de
transmitter to a Selsyn receiver I06 provided with
energized and the rotor 54 remains in the zero
position indicating means I01 and located at any
power flow position.
convenient point for observation. The source of
supply for the Selsyn indicator is indicated by 70 Manual control of power flow through the con
version apparatus is e?ected by means of the
conductors I08 of an auxiliary source of alter
manual control apparatus ‘I0 comprising a push
nating current.
button switch I25 with normally open contacts
The contacts 98 and I02 of the two limit
I26 for one direction of control, and a second
switches 81 and 08 are connected in series with
unidirectional conducting devices, such as contact 75 push‘ button switch I21 with normally open con
as to provide a simple means of obtaining cur
rent flow in either direction in the ?eld windings.
2,407,072
10
tacts I28 for the opposite direction of control.
I41 are interposed between potential transformer
The switch I25 has its contacts I26 connected
I38 and its associated voltage coil I31 of element
in series relation with an adjustable resistor I29
I32. Relay I46 is provided with an operating coil
to the positive conductor of control bus 84, and
I48 which is connected to be energized in accord
switch I21 has its contacts I28 connected to the 5 ance with the operation of position relay 85a
negative conductor of control bus 84 through an
which, in turn, is controlled in accordance with
adjustable resistor I30. The magnitude of the
the cam operated position switch 85 controlling
current in the control ?eld 14 and thus the speed
power flow from circuit I to circuit 6. Relay I41
at which the rotor 54 adjusts load setting is read
is provided with an operating coil I49 which is
ily adjusted by the resistors I29 and I30. With 10 connected to be energized in accordance with the
circuit interrupters I2 and I5 in the closed posi
operation of position relay I I4 which, in turn, is
tion, interlocking contacts I22 are closed so that
controlled in accordance with the cam operated
upon closure of manual control switch I25 the
position switch 86 which controls power flow in
left-hand end of ?eld winding 14 is connected“
the reverse direction, namely, from circuit 6 to
to the positive side of control bus 84 while the 15 circuit I. Similarly, auxiliary reversing relays
right~hand terminal is connected through the
I56 and I5I are interposed between potential
contact 98 of auxiliary switch 81 and through
transformer I43 and its associated voltage coil
recti?er I09 to the midtap of battery 82. This
I42 of element I33. Relays I46 and I50 are ar
circuit effects energization of ?eld winding 14 in
ranged to be operated simultaneously by the op
a direction to cause rotor 54 to be operated in a 20 erating coil I48, while relays I41 and I5I are ar
clockwise direction from A to X, Fig. 2, and thus
increase power flow from the 60 cycle system
(circuit I) to the 25 cycle system (circuit 6). On
the other hand, closure of manual control switch
I21 connects the negative conductor of bus 84
through circuit interrupter interlock contacts
I22 to the left-hand terminal of ?eld winding
14 while the right-hand terminal thereof is con
nected through contact I02 of auxiliary position
switch 88 and the recti?er IIO to the more posi
tive midtap terminal 82 of battery 83. It will be
observed that the polarity of ?eld winding 14
has been reversed so that the motor 6| and
hence rotor 54 would be operated in the reverse
direction to cause an increase in power ?ow from
the 25 cycle system to the 60 cycle system.
The ?rst type of automatic control previously
mentioned and identi?ed in Whole as device 80
may be referred to as “watt regulator” control.
This control is effected by means of an induc
ranged to be operated simultaneously by the
operating coil I49. The two relay elements I 32
and I33 may be constructed in accordance with
the principles of conventional and well known
types of induction disc relays.
The third element of the “watt regulator” I3I
is provided as a calibrating element and com
prises a current winding I52 and a Voltage wind
ing I53 which are arranged in cooperative rela
tion with an induction disc I54 also mounted on
the shaft I45. The current coil I52 is arranged
to be energized with constant current and, as il
lustrated, is connected to be energized from a
current transformer I55. The current trans
former is connected in series relation with a re
sistor I56 across a secondary winding I51 of a
constant potential transformer I58. An adjust
able resistor or voltage divider I59 is also con
nected across the secondary winding I51 of the
constant potential transformer and is provided
tion disc type device I3I comprising three watt 40 with an adjusting arm I60. One terminal of the
responsive elements I32, I33 and I34. The ele
potential coil I53 is connected to the adjusting
ments I32 and I33 are connected in a manner
similar to a conventional two-element three
phase three-wire wattmeter.
Th'us element I 32
is provided with a current coil I35 connected to
be energized in accordance with the upper phase
conductor of circuit II through a current trans
arm I60 and the other terminal is connected to
the other side of the constant potential trans
ex Cal former. The voltage of the potential coil I53 is,
therefore, variable between zero and full voltage
of the transformer I58. By changing the setting
of arm I60, it is possible to vary the torque pro
former I36. This element is also provided with
ducing watts in the calibrating element from
a voltage coil I31 connected to be energized in 01 zero to some predetermined value depending up
accordance Wtih the voltage of the upper two
on the constants of the circuit. The torque of
phase conductors of circuit, II through a poten
calibrating element I34 acts in the same direction
tial transformer I38. The current winding I35
as the torque of elements I32 and I33. An indi~
and voltage winding I31 are arranged in cooper
cating wattmeter I6I, comprising a current cOil
ative relation with an induction disc I39 to pro
5
I62 in circuit with current coil I52 and a voltage
vide a torque proportional to the watts in this
coil I63 responsive to the same voltage as voltage
element. The element I33 is provided with a
coil I53, indicates the watts input to the calibrat
current coil I40 connected to be energized in ac
ing
element I34 so that the indicating wattmeter
cordance with the current in the lower phase
may
be calibrated to read directly the “watt reg
conductor of circuit II through a current trans
ulator” setting.
former I4I. This element is also provided with
The several contacts and cooperating auxiliary
a voltage coil I42 connected to be energized in
relays of the “watt regulator apparatus” 80 may
accordance with the voltage of the lower two
now be considered. The shaft I45 of the “watt
phase conductors of circuit I I through a poten
regulator” device I3I per se is provided with a
tial transformer I43. The current coil I40 and
movable contact arm I64 which may be biased
voltage coil I42 are arranged in cooperative rela
by suitable biasing means I65 to a position in
tion with an induction disc I44 to provide a
termediate two pairs of cooperating contacts I66
torque proportional to the watts in this element.
and I61 and I68 and IE9. Contact I66 is con
The induction discs I39 and I 44 are mounted on
nected to contacts H2 and I I1 of auxiliary relays
a common shaft I45. In order to maintain the
85a and H4, respectively, while contact I 68 is
correct direction of torque on the “watt regu
connected to contacts III and II 6 of auxiliary
lator” relay I3I for different directions of power
relays 85a and H4, respectively. Contacts I61
flow, we have found it expedient to reverse the
and I69 have a common junction I10 which is
connections of the potential coils I31 and I42.
connected through a conductor IN to the left
As illustrated, auxiliary reversing relays I46 and 75 hand terminal of ?eld winding .14 of amplidyne
2,407,072‘
12
tively, while contacts I82 and I83 may be identi~
generator 89. A switch I12 which may be re
?er as the “slow,” “raise” and “lower” contacts,
ferred to as a “watt regulator” transfer switch is
respectively. The “raise” contacts I8I and I82
connected in circuit with conductor I1 I. Switch
are connected through adjustable resistors I85
I12, which may be automatically operated, is
shown, for purposes of simplicity, as a manually CH and I86, respectively, to the positive side of con~
trol bus 84. The “lower” contacts I83 and I84
operated switch and comprises one set of con
are connected through adjustable resistors I81
tacts I13 and a second set of contacts I14. The
and I88, respectively, to the negative side of con
contacts I13 are open and the contacts I14 are
trol bus 84. Separate resistors for “raise” and
closed when the switch is in one operating posi
tion such as the lower or “off” position as illustrated 10 “lower” speed adjustment are used since operat
ing engineers may ?nd it desirable to decrease
in the drawings. In the upper operating position or
the load setting at a faster rate than the load
“on” position, as illustrated in the drawings, con
‘setting is increased, or Vice versa.
tacts I13 are closed and the contacts I14 are open.
To connect the “demand load” regulator into
Contacts I13 are connected in series with con—
the control circuits heretofore described and at
ductor HI and places this circuit under control
the same time switch out other circuits‘ which
of the “watt regulator” 80. Contacts I14 are con
might cause con?icting control, we provide a “de
nected in series with the contacts I26 and I28
mand load” regulator transfer switch I89. This
of the previously described manual control
switch is a two position switch and is provided
switches I25 and I21, respectively. In all cases
with three sets of contacts I98, I9I and I92. In
under “watt regulator” control, the desired di
the lower or “off” position of switch I89, when
rection of power flow must ?rst be selected man
the “demand load” regulator 18 is not intended
ually by the operator by means of switch I25 or _
to effect a controlling action, the contacts I90
I21. We may continue to trace the circuit of
and I9I are in a closed position. Contacts I98
conductor I1I through closed contacts to be de
are in series relation with conductor I1I, making
scribed presently through interlocking circuit in
it possible for watt regulator 80 to exercise con
terrupter contacts I22, which are closed when the
trol, and contacts I9I make it possible for man
power circuit interrupters I2 and I5 are closed, to
ual control to be exercised through manual con
the left-hand terminal of control ?eld winding
trol switch 19. When switch I89 is in its upper
14.
The regulator 18 may be referred to as a “de 30 or “on” position, the contacts I90 and I9I are
in the open position disabling both manual con
mand load regulator” and for purposes of illus
trol 19 and watt control 89 and putting “demand
tration may be assumed to be an indicating-in
load” regulator 18 in control. As previously
tegrating device designed to hold kilowatt hour
pointed out, the “demand load” regulator 18 ex
demand practically constant at a predetermined
ercises its control through ?eld winding 15 rather
value and at the same time hold the instantane
than ?eld winding 14 which is utilized with man—
ous kilowatt value within desired limits, Under
ual control 19 and “watt regulator” 80. Thus,
the assumed system of connections generally out
lined hereinbefore, it will be observed that there
are three sources of power available for the in
dustrial customer’s load 3, (a) the public utility
60 cycle system indicated by circuit I, (b) the
industrial customer’s 60 cycle generators indi
cated by generator 5 and (c) the industrial cus
tomer’s 25 cycle generators indicated by generator
1 feeding into bus 6.
The electronic conversion
apparatus 9 interconnects the 25 cycle system,
with contact I92 closed, a circuit can be com
pleted from either the positive or negative con
ductor of control bus 84, depending upon the po
sition of the regulator arm I19, through inter
locking contacts I24 of circuit interrupters ‘I2 and
I5 through a conductor I93 to the left-hand ter
minal of winding 15. The right-hand terminal
of winding 15 is connected through junction ter
minal 8|, which in turn is connected through
the contacts of limit switches 81 or 88 to the mid
tap 82 of battery 83.
The usual types of faults to which electronic
circuit 6, and the 60 cycle system, circuit I. The
“demand load” regulator 18 is connected to re
spond to the net interchange of power between
the public utility’s 60 cycle system, circuit I, and 50 recti?er apparatus is subjected, such as are
backs, may be taken care of successfully by igni
the‘ power system of the industrial customer.
tor
blocking in, accordance with the system de
The “demand load” regulator may be of a type
scribed and claimed in U. S. Letters Patent No.
commercially available in the art and it is be
2,348,653, granted May 9, 1944 upon an applica
lieved suf?cient for the purpose of disclosing our
tion
of A. H. Mittag and assigned to the assignee
invention to indicate the regulating instrument 55
of
the
present application. In the ignitor block
per so by the rectangular symbol I15. The cur
ing system, means are provided to short circuit
rent element of the regulator I15 is energized
the ignitor ?ring impulses to an entire tube
through a switch I15’ from current transformers
group. We have indicated such blocking for the
I16 connected at the tie point I11 between circuit
ignitors of tube groups I6 and 11 by the ignitor
I and the connection point of the industrial cus
blocking relays 43 and 43', respectively, hereto
tomer’s circuit 4 and electronic converter bus
fore
described. The relays 43 and 43’ are con
II. The voltage element of the device I15 may
trolled by a fault responsive relay I94. The relay
be energized through a suitable potential trans
I94 is provided with an operating coil I95, three
former I18 connected to respond to the voltage
sets
of normally open contacts I96, I91 and I98,
at the tie point I11 or, as illustrated, may be 65
and a normally closed set of contacts I99. The
connected to the bus 4 which has a voltage of
contacts I96 and‘ I98 constitute the ignitor block
predetermined phase, frequency and magnitude
ing control contacts and when closed cause en
relative to the voltage of the tie point I11. The
ergization relays 43 and 43', respectively, over
device I15 is provided with a movable contact arm
control circuits 200 and 20 I, respectively, to short
I19 which is biased by suitable means I80 to
circuit the impulses to the ignitor. The contact
a position intermediate two groups of contacts
I99 is connected in series with the conductor to
I8I and I82 constituting one group and I83 and
the midtap 82 of control battery 83 so that upon
I84 constituting the second group. The outer
closure of contacts I95 and I91 for ignitor block
limit contacts I8I and I84 may be identi?ed as
ing the control of the phase shifting apparatus
the “fast,” “raise” and “lower” contacts, respec
13
2,407,072"
will also be interrupted through the interrup
ratchet wheel Zl? one notch in a counterclock
wise direction and at the same time operates the
time mechanism 2l-9 to release the pawl 2I8 and
satisfactory to use an instantaneous overcurrent
thereby hold the ratchet wheel in the new posi
relay responsive to the alternating current supply
tion. If the number of impulses or energizations
to the respective converters I6 and I? operating
of coil 2I5 are sufficient to move contact arm 2%
as recti?ers. We may obtain this response from
to a predetermined position before the predeter
the current transformers 2% or 293 through se
mined time has elapsed, a pair of contacts 224
lective switch 204 which permits connection of
the fault responsive apparatus to whichever end 10 in series relation with conductor lZI are closed
so that tripping mechanism I20 of circuit inter
of the converter is operating as a recti?er. Al
rupter l2 will be energized and the circuit in
though various known types of overcurrent re
terrupter will be operated to its open position.
lays may be used, we have shown an overcurrent
Otherwise,
if the frequency of occurrence of ig
relay 285 provided with an operating coil 2% con
nitor blocking is less than the predetermined
nected to be energized from a resistor 20'! which, 15
time, the timing mechanism will reset pawl 2I8
in turn, is energized through a full wave recti?er
to a releasing position and the contact arm will
‘298 having its input side connected by selective
tion of the control ?eld windings of generator 69.
For arc-back protection of each recti?er, it is
switch @265.- to either transformer ‘292 or 203. Re
lay 205 is provided with» normally open contacts
269 which when closed complete a control bus 20
circuit indicated by the plus and minus signs to
cause energization of operating coil I95 of the
fault responsive relay 494.
Since an arc-back is also manifested in the
return to its biased position against stop ‘ZZI
without effecting operation of the releasing mech
anism E20 of circuit interrupter i2.
The Operation of the embodiment of our in
vention illustrated in Figs. 1a and 1b is substan
tially as follows: The electronic conversion unit
9 is switched into service by closing the power
circuit interrupters i2 and I5, thereby connecting
direct current circuit of the electronic converter, 25
the transformers It and E3 of the electronic con
we provide a current shunt 2 I 0 in the direct cur
verter unit to the systems I and 6, respectively.
rent loop- 3t and through conductors 2i I energize
The switches it‘ and 416’ are closed to energize
a second relay 252 having normally open con
the excitation control units 36 and 36’, and switch
tacts Elli. The contacts 2&3 are connected in
3' is closed. to interconnect the 60 cycle system 1i
parallel relation with contacts 289 so that op
eration of either relay will cause energization of 30 of the industrial customer with the G0 cycle sys
tem of the public utility system at the tie point
the ignitor blocking relays lit and 43’. Relay 2 l2
Ill. Switch I75’ is closed to energize the poten
also affords protection for a fault condition of
tial coil of “demand load” regulator H5. The
inverter operation which is re?ected on the direct
current circuit and which may not be reflected 35 only prerequisite to putting the unit into serv
ice is that the excitation control units 36 and 36’
in the alternating current circuits of the con
for both ends of the converter be established for
version unit. Under certain fault conditions of
inverter operation. Since the operation of the
the inverter, such as tube failures, mis?re, or in
various control and regulating devices has been
sufficient deionization time, two tubes connected
described hereinbefore relative to their individ
back-to-back, such as the right-hand pair of
ual ‘functions, it is believed an overall description
tubes !8 in group I5, may be simultaneously con
of the operation of the system under control of
ductive during inverter operation. This condi
tion is known as a “shoot-through” and con
stitutes a short circuit on the direct current loop
the several control means will su?ice for a clear
understanding of the illustrated embodiment.
When the switching of the power circuits and
but may not result in abnormally high currents
in the inverter transformer. In this case, the ig 45 auxiliary power circuits has been effected as out
lined above, the power converter is ready for con
nitor blocking relays t3 and 43’ would be picked
trol of direction and magnitude of power flow.
up by the operation of relay ZIZ. Thus either
The operator has a choice of three types of con
an arc-back or an inverter shoot-through will
be successfully cleared by the ignitor blocking
relay.
In the case of repeated arc-backs or shoot
throughs, the fault suppression apparatus will
trol: manual control by device l9, “watt regulator”
50 control by device 80 and “demand load” regula
tor control by device 78. The direction of power
?ow through the electronic converter 9 is deter
mined by the connections of the phase shifting
merely suppress these faults as fast as theyoc
networks
36 and 36'. These connections are
cur. However, it has been found desirable to dis
connect the converter when the fault responsive 55 made by the R and I positions of switches 59 and
50’. When the switch 50 is moved to the I po
means operates a predetermined number of times
sition, the phase shifting network 36 causes the
within a predetermined period of time. In ac
tube group E6 to operate as an inverter, whereas
cordance with our invention, We provide means
when the switch 58 is moved to the R position
for performing this function. For this purpose,
we have illustrated a known form of notching re 60 the phase shifting network 36 causes the tube
group I6 to operate as a recti?er. A correspond
lay ZM which is provided with an operating coil
ing operation is obtained with respect to switch
2l5, a ratchet wheel 2I6, a reciprocating lever
50’ and its associated phase shifting network 33’
mechanism 2 l ‘l, a pawl 2 I8, a delayed time release
and the tube group ll. Therefore, for example,
2I9 for the pawl, and a contact arm 220 operated
by the ratchet wheel. The contact arm is biased 65 to have power flow through the converter 9 from
the 60 cycle system to the 25 cycle system, switch
50 would be moved to the R position and switch
22I by spring 222. The operating coil H5 is con
58' would be moved to the I position. The mag
nected to be energized from a control bus 223
nitude of the power flow through the electronic
through contact I91’ of the ignitor blocking con
converter ‘9 is determined by the magnitude of
70
trol relay I94 each time the ignitor blocking con
the reference voltage derived from induction reg
trol relay is operated to its closed or upper posi
ulator 5| by means of the resistors 48 and 48’
tion as illustrated in Fig. la of the drawings.
associated with the phase shift networks 36 and
When coil 2I5 of the notching relay is energized,
36'. This reference voltage is determined by the
it moves the mechanism 2H 50 as to notch the 75 position of the rotor 54 of induction regulator 5|
to predetermined starting position against stop
2,407,072
15
so that control of the rotation of the rotor 54
is the direct means by which power flow through
the electronic converter '9 is controlled.
Manual control of power flow is by means of the
simple double throw momentary contact control
switch 19. Field winding 14 of amplidyne gen
erator 69 is used for manual control.
Thus if
switch I25 is closed, the left-hand terminal of
?eld winding 14 is connected to the positive ter
minal of control bus 84 through contacts I14, con
tacts I9I, auxiliary contacts I22 of circuit inter
rupter I2, and through conductor I1I. This di
rection of energization has been assumed to cause
clockwise rotation of motor BI and thereby effect
an increase in power flow through the electronic
converter from circuit I to circuit 6. The clo
sure or switch I21 causes the reverse operation
by connecting the left-hand terminal of ?eld
winding 14 to the negative terminal of bus 84.
An operator, therefore, merely selects the desired
position of control switch 19 to give the desired
16
nects the manual control through the opening of
contacts I14. It will be assumed that the oper
ator has moved rotor 54 to a position correspond
ing to position A so that position switch 85 has
been moved to close cntacts 90 and power ?ow has
been initiated through the electronic converter
from circuit I to circuit 6. With the closure of
contacts 98, auxiliary switch 95a is picked up and
closes its contacts I I I, II2 and I I3. Contacts
III connect the “lower” contact I68 to the nega
tive conductor of control bus 84 and contacts II2
connect the “raise” contact I66 to the positive
conductor of the control bus 84. With the power
flow established through the converter from cir
j cuit I to circuit 6, it will be assumed that the
power ?owing is less than the setting of the "Watt
regulator”. Its contact arm I64 would be moved
to close “raise” contacts I66, I61, which results
through contact I I2, in connecting the left-hand
1 terminal of ?eld winding 14 to the positive ter
minal of control bus 84 and thus causes an in
crease in the power flow through the electronic
direction of power flow and the switch is held
converter from circuit I to circuit 6. The opera
in that position until power ?ow has increased to
tion which follows when the power ?ow through
the desired magnitude, such as may be indicated
. the converter is greater than the “watt regulator”
by any conventional wattmeter on the control
' setting will be obvious as the lever I64‘ moves to
board. It will be observed, however, that with
close the “lower” contacts I68, I69 to reverse the
current ?ow from left to right, in ?eld winding
polarity of ?eld winding 14 and thereby reverse
14 the path from the right-hand end or junction
the direction of rotation of rotor 54 of induction
8| to the battery neutral terminal 82 is through
contact 98 of position switch 81 and recti?er I09. 30 regulator 5I. A sequence of events similar to
that just described will occur if the power ?ow is
Thus when rotation of cam 91 has been effected
in the reverse direction through the converter.
in a clockwise direction to a point corresponding
In this case contact 94 of position switch 86 will
to point B in Fig. 2, the field circuit is inter
be closed resulting in picking up relay I I4. This
rupted by switch 98 and no further increase in
action reverses the connection of the potential
power flow can [be effected beyond the established
coils of “watt regulator” 89 for the reverse power
limit by this means. A similar limit is estab
flow and at the same time reverses the connection
lished at point D, Fig. 2, for power flow in the
reverse direction by means of switch 88 and its
cam IUI which opens contact I02 in the circuit
from neutral battery terminal 82 through recti
?er I Ill.
The “watt regulator” 89 is a means for auto
matically regulating the power flow through the
electronic converter 9. The power elements I32
and I33 are connected in the power circuit of the
electronic converter in the manner described
of ?eld winding 14 so that an increase in power
?ow is effected by a counterclockwise rotation of
40 motor 6| and a decrease of power ?ow is e?‘ected
by a clockwise rotation.
The “demand load regulator” is put into opera
tion by moving the “demand regulator” transfer
switch I89 to its “on” or upper position as illus
trated in the drawings. At the same time, the
“watt regulator” transfer switch I12 is moved to
its “oif” or lower position as illustrated in the
drawings. With switch I89 in its “on” position,
its contacts I90 and I9I are opened cutting out
the “watt regulator” control and at the same
time contacts I92 are closed connecting the de
mand regulator contacts I8I to I84 in condition
for effecting control. The “demand load regu
lator” ‘I8 permits the industrial customer to make
above with the potential coil reversing switches
I48 and I49 arranged to connect the potential ele
ments automatically and correctly in accordance
with the operation of position switches 85 and 86.
The regulator 80 has two sets of contacts; one set
I68, I69, which has been identified as the “lower”
set, is closed when the electronic converter power
flow is greater than the regulator calibration, and
another set of contacts I66, I61, which has been 55 the best possible exchange of kilowatt hours with
the public utility system as determined by the
identi?ed as the “raise” set, is closed when the
customer's contract with the power company.
electronic converter power is less than the regu
When the 60 cycle industrial load 3 is greater
lator calibration. Both sets of contacts are open
than the setting of the regulator ‘I8, the elec—
when the electronic converter power flow is equal
to or within a predetermined percentage of the 60 tronic power converter 9 is controlled to supply
power from the customer’s 25 cycle‘ system, cir
regulator calibration. Calibration is changed by
cuit 6, to the 60 cycle system. On the other
the adjusting arm I69 of the calibrating resistor
hand, when the 60 cycle industrial load 3 is less
I59. The indicating instrument I6I may be ar
than the setting of the regulator 18, the elec
ranged to indicate the calibration setting directly
in kilowatts. In putting the electronic converter 65 tronic power converter 9 is controlled to supply
power from the 60 cycle system to the custom
on “watt regulator” control, it is initially neces
er’s 25 cycle system. This control is effected
sary for the operator to select direction of power
through ?eld winding 15, rather than ?eld wind
?ow by means of the manual switch 19. Once
ing 14, of the amplidyne generator 6I. Assume
the rotor 54 of induction regulator 5| arrives at
that when the system is put under “demand load
a position corresponding to position A or C in
regulator” control the integrated load demand of
Fig. 2, the “watt regulator” transfer switch I12
the 60 cycle industrial load is below the setting of
is moved to its upper or “on” position closing con
the regulator 18. These conditions require that
tacts I13 and the “watt regulator” functions to
the power flow to the industrial customer must
pick up the load for which the regulator is set.
This operation of the transfer switch I12 discon 75 increase and this is eifected by causing the elec
2,407,072
‘
17
tronic converter to transmit power from the 60.
cycle system to the 25 cycle system. Therefore,
the movable arm I19 of the regulator 73 moves
to close one of the “raise” contacts I32 or IE!
18
form of reversible motor and for purposes of il_
lustration is shown as a direct current motor with
a split ?eld winding comprising sections 221 and
223 connected to be selectively energized from a
source of direct current 229 through a selector
switch 230. The switch 23!] may be located at any
convenient point for purposes of remote control
and thereby connects the left-hand terminal of
?eld winding ill to the positive conductor of con
trol bus 865. This connection results in a clock
wise rotation of motor
and results in power
and in practice has been mounted on a control
flow from the 60 cycle system to the 25 cycle sys
panel so that the operator can View the indicat
tem in the direction desired. Conversely, if the 10 ing wattmeters l’o‘l and I55’ and thereby deter
integrated load is above the setting of the regu
mine by observation the desired calibration set
later '18 the contact arm I19 is moved to close
ting.
one of the “lower” contacts ass or iii‘! and there~
Each of the calibrating elements of the “watt
by reverses the connections of ?eld winding ‘it.
regulators” to and 88' may be provided with a
This connection results in a counterclockwise r0
load balancing adjuster control which in the case
tation of motor 8| and results in power flow from
the 25 cycle system to the 60 cycle system in the
direction necessary to bring the integrated de
mand down to the setting of the "demand reg-v
ulator.”
In Figs. 3a and I), considered together, we have
shown an embodiment of our invention arranged
for controlling a system in which a plurality of
electronic converters are utilized to interconnect
the assumed 60 cycle and 25 cycle systems. The
“demand load regulator” ‘ill of the single con“
verter system is arranged to control both elec=
tronic converters, while means are provided to
keep the loads on the two electronic converters
approximately equal or in a predetermined ratio
under these conditions of control. rI‘he arrange
ment also illustrates the system with “watt regun
lator” control for each electronic converter unit
and with means for adjusting the calibration of
each “watt regulator.” Although the control cir no In
cuits of each converter unit would be provide
with the manual control 19, as illustrated in Figs.
la
b, it has been omitted from the illustration
of this embodiment in order to simplify the draw~
ings. The various devices and elements of Figs.
3a and 32) corresponding to those of Figs. la and
1b and the electronic converter there she Jl'l have
of watt regulator 89 comprises an adjustable re
sistor 23! connected across the voltage coil I53
and similarly in watt regulator
adjustable
resistor 23!’ connected across the voltage coil
I53’. This control is used only when the elec
tronic converters are both under “watt regulator”
control. Any unbalance of power on the two elec
tronic converters can be corrected by properly
adjusting resistors till end 23l’. The load bal
ance adjusters
and 231' should normally be in
their zero resistance positions and if it is neces
sary to balance the load between the two elec
tronic converters, the resistor for the unit car
rying the smallest load need be the only resistor
changed from the zero position.
When the electronic converters Q and 9’ are
under control of the “demand load regulator” “it,
it may be desirable to provide means to maintain
automatically a predetermined division of load
between the respective converters. For this pur
pose, we provide load balance relays 232 and 232’,
and for purposes of explanation it will be as-.
sumed that it is desired to maintain equal loads
on the respective converters. The load balance
relay 232 may be a conventional polyphase induc
tion disc type relay with current coils 233 and 234
and Voltage coils 235 and 236. The current and
voltage coils 233 and 235 are arranged in coop
been assigned like reference numerals, whereas
corresponding devices and elements of the addi~
erative relation with an induction disc 23? and
tional electronic converters have been assigned 45 the current and voltage coils 231i and 235 are sim
like reference numerals which have been primed
ilarly arranged in cooperative relation with an
and in a few instances double primed where the
induction disc 233. The discs 23'! and 238 are
devices were originally designated by a primed
mounted on a common shaft 239. Load balance
numeral.
relay 232" is constructed in a similar manner
The system as illustrated therefore, com~ 50 with current and voltage coils 233' and 235' in
prises the assumed 60 cycle circuit I of the public
utility, the Si) cycle system Ll of the industrial
customer, both of which are interconnected with
the 25 cycle system of the industrial customer
which is indicated by circuit 5. In the arrange
ment as illustrated two electronic converter cir
cuits, indicated by the buses H and ii’ and in
cooperative relation with disc 23'?’ and current
and voltage coils 234’ and 236' in cooperative
relation with disc 238’ with the discs mounted on
a common shaft 23%’. Current transformers 2618
and 246' are connected, respectively, in the cor
cluding the electronic converters 9 and 9', inter~
tion to energize current coils 233 and 233', Sim
responding outside phase conductors of circuits
H and H’ and are arranged in differential rela
connect the 69 cycle system and the 25 cycle sys
ilarly current transformers 2M and 24! ’ are con
tem. Each of the electronic converters 9 and 9' 60 nected in the corresponding inside phase conduc
is provided with control apparatus corresponding
tors of circuits ii and ii’ and are arranged in
to the apparatus illu"*“-'ated in Figs. 1a and b and
differential relation to energize current coils 23d
except for the addi cnal elements and devices
and 23B’. Voltage coil 235 is connected through
which have been introduced in this modi?cation,
a potential transformer ‘M2 to the phase voltage
it is not believed that
further description is
of its associated current coil 233 of circuit H and
required for an understanding of the invention.
voltage coil 23% is connected through potential
In connection with the “watt regulators” {ill
transformer 253 to the phase voltage of its as
and 8%’ means are provided to adjust the calihra~
sociated core coil 235i. Voltage coils 235' and 235'
tion of these regulators simultaneously and this
are similarly connected to circuit l I’ through 120"
may be accomplished through the calibrating
tential transformers 252' and Ell-3'. The shaft 239
rheostats E59 and IE9’ by means of a shaft 225
of relay 232 is provided with a movable contact
having the contact arms E66 and Hill’ mounted
arm Mil biased by suitable means 245 to a posi~
thereon. A reversible driving means, such as the
tion intermediate one pair of "raise” contacts 245
reversible motor 226, is arranged to operate the
and 241 and a second pair of “lower” contacts 243
shaft 225. The motor ‘1"!’ may be any suitable
and 24?. The shaft 239' of relay 232' is similarly
2,407,072
19
20
will be brie?y tabulated for unbalance of load
on the respective electronic converters 9 and 9’.
constructed with a movable contact arm 244'.
bias means 245’ and cooperating “raise” contacts
248-24? and “lower” contacts Mir-249C The
The relays are connected to close their contacts
as follows:
interconnected or common contacts 246 and 248
of relay 882 are connected through a pair of con—
tacts 258 which have been added to “watt reg»
Power flow 60 cycle system to 25 cycle system
Converter 9 carrying greater load
Relay 232 contacts 245-248 closed, contacts
ulator” transfer switch I12. By reason of the
addition of the load balancing relays 232 and
232’, additional contacts are required on the “de
mand load” transfer switches I89 and I89’.
246-241 open
Relay 232' contacts 246’-°4'l' closed, contacts
246’-248’ open
Converter 9’ carrying greater load
Relay 232 contacts 248-241 closed, contacts
246-248 open
Relay 232’ contacts 246’-248' closed, contacts
246'-241’ closed
Power ?ow 25 cycle system to 60 cycle system
Converter 9 carrying greater load
Relay 232 contacts 25.6-248 closed, contacts
These contacts are identi?ed as 25! and 252 on
switch I89 and. 25!’ and 252' on switch I89’.
Thus from contacts 258 of watt transfer relay I12,
the control circuit may be traced through con
tacts 252’ of relay I89’, through contacts 25! of
relay 188, through contacts I22 of circuit inter
rupter l2 to the right-hand terminal of ?eld
winding 14 of amplidyne generator 69. Proceed
ing in the opposite direction from contacts 250
this right-hand terminal of winding 14 is then
connected to the positive conductor of bus 84
through auxiliary relay 85a or the negative con
ductor of bus 84 through auxiliary relay I 14, de
pending upon the operation of position switches
85 and 86 and whether the load balancing relay
246-241 open
Relay 232' contacts 246’-241’ closed, contacts
246'-248' open
Converter 9’ carrying greater load
232 is in its “raise” or “lower” position. The op
Relay 232 contacts 248-241 closed, contacts
posite or left-hand terminal of ?eld winding 14 is
246-248 open
conected through the limit switches 81 or 88 to
Relay 232' contacts 24B'-248’ closed, contacts
the neutral terminal 82 of the battery 83. The
246’-24'|' open
left-hand terminal of ?eld winding 14' of am 30
plidyne generator 69' is similarly connected to
the plus or minus conductor of bus 84, depend
ing upon the operation of the position switches
85’ and 86’ and whether the load balance relay
232’ is in its “raise” or “lower” position. The :
right-hand terminal of ?eld winding 14’ is con
nected through limit switches 81' or 88' to the
neutral terminal 82 of battery 83. With equal
loads on the respective electronic converters 9
and 9' and with the differential arrangement of 4.0
the current transformers of the balance relays
232 and 232', no current flows in the current coils
of either relay and the relays “?oat.”
In analyzing the operation of relays 232 and
232’, it is necessary to keep in mind that the
motor 6|, amplidyne generator 69 and the po
sition switches in Fig. 3a are reversed in posi~
tion. as illustrated, from that of the correspond~
ing elements in Fig. 3b and also from the cor“
responding elements in Fig. 1b. Hence, it is
necessary in Fig. 3a to reverse the convention in
regard to e?ecting a decrease or increase in power
?ow between the respective alternating current
circuits. The convention may be correctly kept
in mind by considering a mirror image of Fig. 2
so that when power ?ow is from the 60 to 25
A study of Figs. 3a and 3b and the above tab
ulation will show that in all cases the relays 232
and 232’ operate to balance the power flow for
the two electronic converters. For example, as~
sume that power flow is from the 60 cycle to
the 25 cycle system and that converter 9 is car
rying the greater load. This requires that relay
232 reduce the load of converter 8 and increase
the load of converter 9’. For the assumed di
rection of power ?ow and reversed convention
for the control apparatus of Fig. 3a, motor 8|
will be required to rotate in a clockwise direc
tion which requires that ?eld winding 14 be made
negative at the right-hand terminal. When It,‘
lay 232 moves to close its “lower” contacts
246-248, relay I89 is picked up and connects
the right-hand terminal of ?eld winding 3 to the
negative conductor of bus 84 thereby reducing
the power ?ow of converter 9. At the same time,
relay 232’ moves to close its “raise” contacts
246’-241' which effects a clockwise rotation of
motor 6|’ and thereby raises the power ?ow
through converter 9’. When the load on the two
electronic converters becomes balanced, the re
lays 232 and 232’ open their contacts and the
contact arms “?oat” in the neutral position. The
cycle system a counterclockwise rotation of posi—
“demand load regulator” 18 functions to control '
tion switch 85 effects an increase in power flow
and a clockwise rotation a decrease. Converse~
1y, when power ?ow is from the 25 to 60 cycle
system, a clockwise rotation of position switch
both converters in the manner described here
inbefore so as to maintain the net interchange
85 effects an increase in power ?ow and a coun
terclockwise rotation a decrease. The conven-
tion with respect to the direction of rotation of
motor 6| in relation to the direction of energize."
tion of ?eld winding 14 remains the same since
current flow from right to left is assumed to cause
a counterclockwise rotation of motor 6! and en~
0 of power at the desired value determined by the
‘
demand load setting.
While we have shown and described particu
lar embodiments of our invention, it will be ob
vious to those skilled in the art that various
Cir changes and modi?cations may be made with
out departing from our invention and we, there
fore, aim in the appended claims to cover all such
changes and modi?cations as fall within the true
spirit and scope of our invention.
ergization from left to right is assumed to cause
a clockwise rotation. In connection with motor 70 What we claim as new and desire to secure
BI’ and amplidyne generator ?eld 14’ of Fig. 3b
by Letters Patent of the United States is:
1. In an electronic conversion system, a pair
the same convention is observed as for the cor
of circuits one of which is an alternating current
responding elements in Fig. 1b.
circuit, means comprising electric translating ap
With the stated conventions in mind the op
eration of the load balance relays 232 and 232' 75 paratus interconnecting said circuits and com
211
2,407,072
22
prising a plurality of electronic tubes each hav
met’ current voltage for energizing said control
?eld winding, means for reversing the polarity of
ing' an anode, a cathode and a control electrode,
means having a rotatable element for control
ling the potential of said control electrode to de
termine the instant of conduction between the
anode and cathode of each tube, a direct cur
rent motor connected to operate said movable
element, a direct current generator of the arma
the energization of said control ?eld winding from
said source, and means operated by said motor for
selectively determining the extent and direction
of rotation of said motor in accordance with the
position of said movable element. ,
5. In a control system, a dynamo-electric ma
ture reaction-excited type connected to energize
said motor and having a pair of short circuit 10 chine, a control ?eld winding therefor having two
terminals, means for energizing said ?eld wind
brushes and a pair of load circuit brushes dis
ing comprising a source of unidirectional voltage
placed therefrom, a control ?eld winding for said
having positive and negative terminals and an
generator, and means connected to said control
intermediate terminal, means comprising a two
?eld winding and responsive to an electrical con
branch circuit for interconnecting one terminal
dition of said conversion unit for controlling the
of said ?eld winding to said intermediate termi
power interchanged between said pair of circuits.
nal and having in one branch a circuit interrupt
2. In an electronic conversion system, a pair of
ing device and a unidirectional conducting device
circuits one of which is an alternating current
poled in a direction for current flow through said
circuit, means comprising electric translating ap
?eld winding in one direction and having in the
paratus interconnecting said circuits and com
other branch a circuit interrupting device and a
prising a plurality of electronic tubes each hav~
unidirectional conducting device poled in a di
ing an anode, a cathode and a control electrode,
rection for current flow through said ?eld wind
means having a rotatable element for controlling
ing in the opposite direction, and means for se
the potential of said control electrode to deter
lectively connecting the other terminal of said
mine the instant of conduction between the anode
?eld winding to the positive or negative terminal
and cathode of each tube, a direct current motor
of said unidirectional source.
connected to operate said movable element, a di
6. In a control system, a direct current gener
rect current generator of the armature reaction
ator having a control ?eld winding provided with
excited type connected to energize said motor
two terminals, means for energizing said ?eld
and having a pair of short circuit brushes and a
winding comprising a source of unidirectional
pair of load circuit brushes displaced therefrom, a
voltage having positive and negative terminals
control ?eld winding for said generator, and
and an intermediate terminal, means comprising
means for selectively varying the polarity of the
a two-branch circuit for interconnecting one ter
voltage of said generator for operating said mo
minal of said ?eld winding to said intermediate
tor in either direction of' rotation comprising
terminal and having in one branch a circuit in
means for reversibly energizing said control ?eld
terrupting device and a unidirectional conduct
winding.
ing device poled in a direction for current flow
3. In combination, a pair of electric circuits,
through said ?eld winding in. one direction and
means interconnecting said circuits and compris
having in the other branch a circuit interrupt
ing a movable element operable from a ?rst pre
ing device and a unidirectional conducting device
determined position to a second predetermined
poled in a direction for current ?ow through said
position in one direction of rotation for effecting
a change in one sense between an electrical con
dition of said circuits and operable from said
?rst predetermined position to a third predeter
mined position in the opposite direction of rota
tion for e?ecting a change in the opposite sense
between said electrical condition of said circuits,
a direct current motor reversible in its direction
of rotation for operating said movable element,
a reversible polarity direct current generator pro
vided with a control ?eld winding and connected
to energize said motor, a source of direct current
voltage for energizing said control field winding,
61
?eld winding in the opposite direction, means for
selectively connecting the other terminal of said
?eld winding to the positive or negative terminal
of said unidirectional source, and means for se
lectively controlling said circuit interrupting de
vices.
7. In a control system, a reversible polarity di
rect current generator having a separately ener
gized control ?eld winding, a direct current motor
connected to be energized from said generator
and having a direction of rotation dependent
upon the polarity of said generator, means for en
ergizing said ?eld winding comprising a source
means for reversing the polarity of the energiza
of unidirectional voltage having positive and Mg _
tion of said control ?eld winding from said source,
ative terminals and an intermediate terminal,
and means for selectively determining the extent
means comprising a two-branch circuit for inter
and direction of rotation. of said motor in accord
connecting one terminal of said ?eld winding to
ance with the position of said movable element,
4. In combination, a pair of electric circuits, 60 said intermediate terminal and having in one
branch. a circuit interrupting device and a uni
phase shifting means interconnecting said circuits
directional conducting device poled in a direction
and comprising a movable element operable from
for current ?ow through said ?eld winding in one
a ?rst predetermined position to a second pre
direction and having in the other branch a circuit
determined position in one direction of rotation
for effecting a change in. phase in one sense be 65 interrupting device and a unidirectional conduct_
tween the voltage of said circuits and operable
ing device poled in a direction for current ?ow
from said ?rst predetermined position to a third
through said ?eld winding in the opposite direc
predetermined position in the opposite direction
tion,
for selectively connecting the other
of rotation for effecting a change in phase in the
terminal of said ?eld winding to the positive or
opposite sense between the voltages of said cir 70
_ ,tive terminal of said unidirectional source,
cuits, a direct current motor reversible in its di
means operative in response to the rotation of
rection of rotation for operating said movable
said motor in one direction for controlling said
element, a reversible polarity direct current gen
circuit interrupting device of said one branch,
erator provided with a control ?eld winding and
and means operative in response to the rotation
connected to energize said motor, a source of di 75 of said motor in the other direction for control.
2,407,072
23
ling said circuit interrupting device of said other
branch.
8. In a control system, a reversible polarity
direct current generator having a separately en
ergized control ?eld winding, a direct current
motor connected to be energized from said gener
ator and having a direction of rotation depend
ent upon the polarity of said generator, means
for energizing said ?eld winding comprising a
source of unidirectional voltage having positive
and negative terminals and an intermediate ter
minal, means comprising a two-branch circuit
for interconnecting one terminal of said ?eld
winding to said intermediate terminal and hav“
ing in one branch a circuit interrupting device 15
and a unidirectional conducting device poled in
a direction for current ?ow through said ?eld
winding in one direction and having in the other
branch a circuit interrupting device and a uni
directional conducting device poled in a direc~ 20
tion for current flow through said ?eld winding
in the opposite direction, means comprising a
pair of control circuits each having two circuits
arranged for selectively connecting the other terminal of said ?eld winding to the positive or 25
negative terminal of said unidirectional source,
means operative in response to the rotation of
said motor in one direction for controlling said
circuit interrupting device of said one branch
during control of said motor in one direction for 30
either corresponding circuit of said pair or" con
trol. circuits, and means operative in response to
the rotation of said motor in the other direction
for controlling said circuit interrupting device
24,
moelectric machine having a plurality of control
?eld windings each provided with two terminals,
means for energizing said control ?eld windings
comprising a source of unidirectional voltage
having positive and negative terminals and a
terminal intermediate thereof, means compris—
ing a two-branch circuit for interconnecting one
terminal of all of said ?eld windings to said
intermediate terminal and having in one branch
a unidirectional conducting device poled in a
direction for current ?ow from said ?eld, wind
ings to said intermediate terminal and having
in the other branch a unidirectional conducting
device poled in a direction for current flow from
said intermediate terminal to said ?eld windings,
and means for reversing the current flow in the
respective ?eld windings comprising means con
nected to the other terminal of each ?eld wind
ing for selectively connecting said other termi
nals of its associated ?eld winding to the posi
tive or negative terminal of said source of uni
directional voltage.
,
11. In a control system, a direct current dy
namoelectric machine having a plurality of con
trol ?eld windings each provided with two ter~
minals, means for energizing said control ?eld
winding comprising a source of unidirectional
voltage having positive and negative ter ninals
and a terminal intermediate thereof, means com
prising a two-branch circuit for interconnecting
one terminal of all of said ?eld windings to said
intermediate terminal and having in one branch
a unidirectional conducting device poled in a
direction for current ?ow from said ?eld wind
ings to said vintermediate terminal and having in
of said other branch during control of said mo
the other branch a unidirectional conducting de
tor in te other direction for either of the other
vice poled in a direction for current flow from
circuits of said pair of control circuits.
said intermediate terminal to said ?eld wind
9. In a control system, a reversible polarity
ings, means for reversing the current ?ow in
direct current generator having a separately en
ergized control ?eld winding, a direct current 40 the respective ?eld windings comprising a pair
ofv control circuits connected to the other ter
motor connected to be energized from said gen
minal of each ?eld winding for selectively con
orator and having a direction of rotation de
necting said other terminals of its associated
penden’r upon the polarity of said generator,
?eld winding to the positive or negative termi
means for energizing said ?eld winding compris
nal of said source of unidirectional voltage, and
ing a source of unidirectional voltage having
adjustable resistance means connected in each
positive and negative terminals and an interme
circuit of at least one of said pair of control
diate terminal, means comprising a two-branch
circuits.
,
circuit for interconnecting one terminal of said
12. In a control system, a direct current gen
?eld winding to said intermediate terminal and
erator of reversible polarity having a plurality
having
one branch a circuit interrupting de
of control ?eld windings each provided with two
vice and imidirectional conducting device poled
terminals, means for energizing said ?eld wind
in a direction for current ?ow through said ?eld
ings comprising a source of unidirectional volt
windir in one direction and having in the other
branch a circuit interrupting device and a uni
directional conducting device poled in a direc
tion for current ?ow through said ?eld winding
in the opposite direction, means comprising a
pair oi manual control circuits and a pair of
automatically controlled circuits each having two
age having positive and negative terminals and
an intermediate terminal, means comprising a
two-branch circuit for interconnecting one termi
nal of each of said ?eld windings to said inter
mediate terminal and having in one branch a
unidirectional conducting device poled in a direc
circuits arranged for selectively connecting the 60 tion for current flow through each ?eld winding
in one direction and having in the other branch
other term 1a]. of said ?eld winding to the posi
a unidirectional conducting device poled in a di
tive or negative terminal of said unidirectional
rection
for current flow through said ?eld wind
source, means operative in response to the rota~
ings in the opposite direction, and means for se
tion of said, motor in one direction for control—
ling the circuit interrupting device associated" lectively connecting the other terminal of each
?eld winding to the positive or negative terminal
with the unidirectional conducting device trans
of said unidirectional source for reversing the
' mitt‘ng current in one direction under either said
polarity of said generator.
manual or automatically controlled circuits, and
13. In a control system, a direct current gen
means operative in response to the rotation of
said motor in the other direction for controlling 70 erator of reversible polarity having a plurality
of control ?eld windings each provided with two
the circuit interrupting device associated with
terminals, means for energizing said ?eld wind
the unidirectional conducting device transmit
ings comprising a source of unidirectional voltage
ting current in the other direction under either
having positive and negative terminals and an
said manual or automatically controlled circuits.
intermediate terminal, means comprising a two
10. In a control system, a direct current dyna-'
2,407,072
25
branch circuit
interconnecting one terminal
of each of said ?eld windings to said intermedi
ate terminal and having in one branch a unidi
rectional conducting device poled in a direction
for current ?ow through each ?eld winding in
one direction and having in the other branch a
2%
direction of energization of said control ?eld
winding, a ?rst pair of switching means connect
ed in circuit with one terminal of said ?eld wind
ing for selectively connecting said one terminal
for energization in one direction or in the reverse
direction in dependence upon the direction of
unidirectional conducting device poled in a direc~
rotation of said rotatable element from said neu
tion for current flow through said ?eld windings
tral position, a second pair of switching means
in the opposite direction, means comprising a pair
of control circuits for selectively connecting the 10 connected to said other terminal of said control
?eld winding for interrupting the circuit of‘ said
other terminal of each field winding to the posi
control
?eld winding upon operation of said ro
tive or negative terminal of said unidirectional
tatavblel element to either one of its limit control
source for reversing the polarity of said generator,
positions, means responsive to interruption of
and adjustable resistance means connected in
current flow in said electric circuit for causing
each circuit of said pair of control circuits,
15 energizatlon of said ?eld Winding in a direction
14. In combination, a reversible polarity direct
to return said rotatable element to said neutral
current generator having a separately energized
position, and‘means controlled by said ?rst pair
control ?eld winding, a direct current motor con
of switching means for interrupting current ?ow
nected to be energized from said generator and
in
said control ?eld winding upon arrival at said
being operable in opposite directions of rotation
neutral position from either direction of travel
in dependence upon the polarity of said genera
therefrom.
,
,
tor, a source of voltage for energizing said ?eld
18.
In
combination,
a pair of alternating cur
Winding, means for selectively energizing said
rent circuits, power conversion apparatus inter
?eld winding from said source for reversing the
connecting said Halternating current circuits,
polarity of said generator, and adjustable means [C Li means
for controlling the power ?ow through said
in circuit with said last mentioned means for
conversion
apparatus, means including a watt re
causing operation of said motor at different
sponsive device connected to be responsive to the
speeds for opposite directions of rotation.
_
power flow through said conversion apparatus
15. In combination, a rotatable element for
and having a control element for effecting a con
controlling an electrical condition of an electric
trolling action in oppositesenses when the power
circuit, a reversible electric motor for operating
?ow in a given direction through said conversion
said rotatable element in oppositedirections from
apparatus, is above or below a predetermined
a predetermined neutral position for e?ecting the
value, and means for controlling said ?rst men
controlling action of said rotatable element, a
tioned means in accordance with the operation
generator provided with a control ?eld winding
and having one polarity or the reverse thereof in
dependence upon the direction of energization of
said control ?eld winding, said generator being
connected to energize said motor, means for re
versibly energizing said control ?eld winding, and
means responsive to interruption of current ?ow
in said electric circuit for causing energization
of said ?eld winding in a direction to return said
rotatable element to said neutral position.
16. In combination, an electric circuit, circuit
interrupting means connected in said electric cir
cuit, means for controlling an electrical condition
of said electric circuit comprising a, rotatable ele
ment, a reversible electric motor for operating
said rotatable element in opposite directions from
a predetermined neutral position for effecting the
controlling action of said rotatable element, a
of said control element.
39. In combination, a pair of alternating cur
rent circuits, powerconversion apparatus inter~
connecting said alternating current circuits,
means for controlling the power flow through
said conversion apparatus, means including a
watt responsive device connected to be responsive
to the power ?ow through said conversion appa
ratus and having a control element for effecting
a controlling action in opposite senses when the
power ?ow in a given. direction through said
conversion apparatus
above or below a prede
termined value at which said control element is
inactive, means vfor calibrating said watt re»
sponsive device to establish the predetermined
value of power flow at which said control element
is inactive, means for changing the setting of
said calibrating means, and means for control
generator provided with a control ?eld winding
ling said ?rst mentioned mean“ in accordance
and having one polarity or the reverse thereof in
dependence upon the direction of e-nergization of 55 with the operation of said control element.
20. In combination, a pair of alternating cur
said control ?eld winding, said generator being
rent
circuits, power conversion apparatus inter
connected to energize said motor, means for se
lectively energizing said control ?eld winding in
one direction or the other, and means operative
connecting said alternating current circuits,
means for controlling the power flow through
said conversion apparatus, means including a
watt responsive device connected to be responsive
to the power flow through said conversion appa
ratus and having a control element actuated
in response to operation of said circuit interrupt
ing means to interrupt said electric circuit for
causing energization of said ?eld winding in a
direction to return said rotatable element to said
neutral position from its position in either direc
thereby for effecting 'a controlling action in on
tion from said neutral position.
pcsite senses when Dower flow in a given direc
,
1'7. In combination, a rotatable element for
tion through said conversion apparatus is above
controlling an electrical condition of an electric
or below a predetermined value at which said
circuit, said rotatable element having a neutral
control element is inactive, means for calibrat
position intermediate limit control position for
ing said watt responsive device to establish the
either direction of rotation from said neutral p07 70 predetermined value of power ?ow at which said
sition, a reversible electric motor for operating
control element is inactive, means for indicating
said rotatable element in opposite directions from
the calibration of said watt responsive device,
said neutral position, a generator provided with
means for changing the setting of said calibrat~
a control ?eld winding and having one polarity
or the reverse polarity in dependence upon the
ing means in accordance with the indication of
said indicating device, and means for controlling
2,407,072
27
said ?rst mentioned means in accordance with
the operation of said control element.
21. In combination, a pair of alternating cur
rent circuits, reversible power conversion appa
ratus interconnecting said alternating current
circuits, means for controlling the power ?ow
through said conversion apparatus, means in
cluding a watt responsive device connected to be
responsive to the power flow through said con
version apparatus and having a torque producing
element and a control element actuated thereby
for effecting a controlling action in opposite
senses when the power flow through said con
version apparatus is above or below a predeter
mined value, means for maintaining the torque
of said watt responsive device in the same direc
tion irrespective of the direction of power flow,
and means for controlling said ?rst mentioned
means in accordance with the operation of said
control element above or below said predetere
mined value during either direction of power flow.
said load circuit, a supplementary source of en
ergy also connected to energize said load circuit,
a second alternating current system, a second sup
plementary source of energy connected to ener
gize said load circuit and comprising a power con
version unit interconnecting said second alter
hating current system and said load circuit,
22. In combination, a pair of valternating cur
rent circuits, reversible power conversion appa
ratus interconnecting said alternating current
circuits, means for controlling the power ?ow
through said
28
ing a controlling action in opposite senses when‘
the power flow in a given direction through its
associated conversion unit is above or below a
predetermined value at which said control ele
ment is inactive, adjustable means connected to
each watt responsive device for adjusting the
ratio of power flow of said pair of conversion
units, and means associated with each of said
watt responsive devices for controlling said ?rst
mentioned means in accordance with the opera
tion of the control element of its associated watt
responsive device.
25. In an electric power system, a load circuit,
a first alternating current system constituting a
principal source of energy connected to energize
means for varying the power ?ow in either direc
tion through said conversion unit, said principal
source and two supplementary sources of energy
being connected at a common tie point for jointly
energizing said load circuit, an integrating de
mand measuring instrument connected at said
tie point to be energized in accordance with the
net interchange of energy between said principal
conversion apparatus, manual
means interconnected with said ?rst mentioned
means for selecting the direction of power flow
through said conversion apparatus and varying
said power ?ow in either direction, automatic
means including a wattmeter device connected
source and said supplementary sources, said meas~
uring instrument being provided with a control
element, and means controlled by said control ele
ment for controlling said ?rst mentioned means
to cause said conversion unit to transmit power
to be responsive to the power ?ow through said
conversion apparatus above or below a predeter
mined value for controlling said first mentioned
means, and means for transferring the control
of said ?rst mentioned means from said manual
from said second alternating current system to
said first alternating current system when the
means to said automatic means or vice versa.
energy demand of said load is above said prede
termined value and to transmit power in the re
interconnecting said alternating current circuits, 40 verse direction when the energy demand of said
load is below said predetermined value.
means for controlling the power flow through
26. In an electric power system, a load circuit,
each of said conversion units, means including
a ?rst alternating current system of one fre
a pair of watt responsive devices arranged one
quency constituting a principal source of energy
with each of said power conversion units and
23. In combination, a pair of alternating cur
rent circuits, a pair of power conversion units
each watt responsive device being connected to be
responsive to the power ?ow through its asso
ciated conversion unit, each watt responsive de
vice being provided with a control element for
effecting a controlling action in opposite senses
when the power flow in a given direction through
its associated conversion unit is above or below
a predetermined value at which said control ele
ment is inactive, calibrating means connected to
each watt responsive device to establish the pre
determined value of power flow at which the
control element of its associated device is inac
tive, adjustable means associated with each of
said calibrating means for changing the setting
thereof, means for simultaneously adjusting said
adjustable means, and means associated with
each of said watt responsive devices for control
ling said ?rst mentioned means in accordance
with the operation of the control element of its
associated watt responsive device.
24. In combination, a pair of alternating cur
rent circuits, a pair of power conversion units
connected to energize said load circuit a supple
mentary source of energy of the same frequency
as said first alternating current system connected
to energize said load circuit, a second alternat
C; C.
ing current system of a different frequencythan
said ?rst alternating current system, a second
supplementary source of energy connected to en~
ergize said load circuit and comprising an elec
tronic power conversion unit interconnecting said
second alternating current system and said ?rst
alternating current system, means for varying
the power flow in either direction through said
conversion ‘unit, said principal source and said
two supplementary sources being connected at a
common tie point for jointly energizing said load
circuit, an integrating demand measuring instru
ment connected at said tie point to be energized
in accordance with the net interchange of en
ergy between said principal source and said sup
plementary sources, said measuring instrument
' being provided with a movable control element
constrained to a neutral position for a predeter
mined value of said net interchange of energy and
operated to one or the other of two controlling
means for controlling the power flow through
positions when the net interchange of energy
each of said conversion units, means including
a pair of watt responsive devices arranged one 70 is above or below said predetermined value, and
means operative in response to movement of said
with each of said power conversion units and
movable control element to one or the other of
each watt responsive device being connected to
its controlling positions for controlling said ?rst
be responsive to the power flow through its associ
mentioned means to cause said converter unit
ated conversion unit, each watt responsive device
being provided with a control element for effect 75 to transmit power from said second alternating
interconnecting said alternating current circuits,
29
2,407,072
30
current system to said ?rst alternating current‘
system when the energy demand of said load is
above said predetermined value and to transmit
second supplementary source of energy connected
to- energize said load circuit and comprising a
value.
ing the power ?ow in either direction through
said conversion units, said principal source and
pair of power conversion units connected in par
power in the reverse direction when the energy
allel relation between said second alternating cur
demand of said load is below said predetermined Di rent system and said load circuit, means for vary
27. In con-ibination, a pair of alternating cur
rent circuits, a pair of parallel connected power
two supplementary sources of energy being con
nected at a common tie point for jointly ener
conversion units interconnecting said alternating
current circuits, means arranged with each of .
gizing said load circuit, an integrating demand
measuring instrument having voltage and current
said conversion units for controlling the power
?ow through its associated conversion unit, means
coils connected at said tie point to be energized
in accordance with the net interchange of energy
between said principal source and said supple
including a pair of Watt responsive'devices ar
ranged one with each of said power conversion
units and each watt responsive device being con
nected to be responsive to the difference in power
mentary sources, said measuring instrument be
ing provided with a control element, means con
transmitted by the respective units of said pair
of conversion units, and circuit controlling means
for each watt responsive device having an inac
tive position when the watts of the respective ~'>
trolled by said control element for simultaneously
controlling said first mentioned means to cause
said conversion units jointly to transmit power
from said second alternating current system to
said ?rst alternating current system when the
energy demand of said load is above said prede
termined value and to transmit power in the
conversion units are in a predetermined ratio and
each having one or the other of two control po
sitions for controlling the ?rst mentioned means
of its associated conversion unit to increase or
decrease the power ?ow of its associated conver“
sion unit in dependence upon the direction of de
parture of watts in the respective conversion units
from said predetermined ratio.
28. In combination, a pair ofalternating cur
rent circuits, a ?rst and second power conver
reverse direction when the energy demand of
l
said load is below said predetermined value, and
means associated with each of said conversion
units and responsive to the ratio of load trans
mitted by the respective conversion units for mod
ifying said ?rst mentioned means to adjust the
30 loading between said conversion units to- a prede
sion unit connected in parallel relation between
termined ratio.
said alternating current circuits, means for con
30. In combination, a supply circuit, a load cir
trolling the power ?ow through said ?rst conver
cuit, electric translating apparatus connected be
sion unit, means for controlling the power flow
tween said circuits and including electronic means
through said second conversion unit, a ?rst watt
having an anode, a cathode and a control mem
responsive device including a currengt coil con~
her, an excitation circuit comprising a source of
nected to be energized in accordance with the
alternating current connected to energize said
differential current of the respective conversion
control member, circuit interrupting means con~
units and a voltage coil energized in accordance
nected between one of said circuits and said elec
with the voltage of one of said circuits, a second 40 tric translating apparatus, means responsive to
watt responsive device including a current coil
an abnormal operating condition of said electric
connected to be energized in accordance with the
translating apparatus for causing deenergiza
differential current of the respective conversion
tion of. said control member, and means for caus
units and a voltage coil energized in accordance
ing said circuit interrupting means to disconnect
with the voltage of said one of said circuits, a _ said electric translating apparatus from one of
movable contact arm arranged to be operated by
said circuits after a predetermined number of
said first watt responsive device from an inactive
operations of said last mentioned means in a pre
circuit controlling position for a predetermined
determined period of time.
ratio of watts in the respective conversion units
31. In combination, a supply circuit, a load cir
to one or the other of two active circuit control
cuit, electronic power conversion apparatus con
ling positions in dependence upon the magnitude
and direction of the differential watts of said
?rst watt responsive device, means operative in
response to movement of said contact arm to
either one of its active circuit controlling posi
tions for controlling said ?rst mentioned means,
a movable contact arm arranged to be operated
by said second watt responsive device from an
inactive circuit controlling position for the said
nected between said circuits and comprising elec
tronic means of the type employing an ionizable
medium and including an anode, a cathode and
an arc-initiating control member, an excitation
circuit connected to said control member and
comprising a source of alternating current and an
inductive device interposed between said source
and said control member for transmitting elec
trical impulses thereto, means for controlling said
predetermined ratio of watts in the respective
60 inductive device to prevent the application of elec
conversion units to one or the other or two active
trical impulses thereto, circuit interrupting means
circuit controlling positions in dependence upon
connected between said supply circuit and said
the magnitude and direction of the differential
power conversion apparatus, means responsive
watts of said second watt responsive device, and
to an abnormal current condition of said power
means operative in response to movement of the 65 conversion apparatus for causing operation of said
contact arm of said second watt responsive de
?rst mentioned means, and means for causing said
vice to either one of its active circuit controlling
circuit interrupting means to disconnect said sup
positions for controlling said second mentioned
ply circuit from said power conversion apparatus
means.
after said ?rst mentioned means has performed
29. In an electric power system, a load cir
a predetermined number of its circuit controlling
cuit, a ?rst alternating current system constitut
operations in a predetermined period of time.
ing a principal source of energy connected to
32. In combination, a pair of alternating cur
energize said load circuit, a supplementary source
rent circuits, electronic power conversion ap
of energy also connected to energize said load
paratus connected between said circuits and com
circuit, a second alternating current system, a
prising two electronic conversion units, each unit
2,407,072
31
being Operable as a recti?er or an inverter, a
direct current circuit interconnecting said units,
each conversion unit also comprising electronic
means of the type employing an ionizable medium
and including an anode, a cathode and an arc
initiating control member, a source of excitation,
means including a transformer for interconnect
ing said source and said control member for supi
32
sponsive to alternating current above a predeter
mined value transmitted to a conversion unit
when operating as a recti?er from its associated
alternating current circuit, means responsive to
the current of said direct current circuit above
a predetermined value, relay means responsive to
the operation of either of said two last men
tioned means for operating said shunting means,
and means for energizing one of said circuit open
an are between said anode and cathode, shunting 10 ing control circuits to cause opening of its asso~
ciated circuit breaker after said shunting means
means for rendering said transformer ineffective,
has been operated a predetermined number‘of
a circuit breaker connected between each conver~
times in a predetermined period of time.
sion unit and its associated alternating current
plying thereto electrical impulses for initiating
circuit and each circuit breaker being provided
with a circuit opening control circuit, means re- i
mum
WILLIAM N. GITTINGS;
AMOS W. BATEMAN,
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