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Патент USA US2412442

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Dec. 10, 1946.
F. E. CREVER ETAL
2,412,442
REGULATOR SYSTEM
2 Sheets-Sheet l
Filed July 1, 1945
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F. E. CREVER ETAL
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REGULATOR SYSTEM
Filed July 1, 1943
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Inventors :
Frederick E. Cr‘ever,
v
Leonard C. ?elder,
by WW6
Their- Attorney
Patented Dec. 10, 1946
2,412,442
UNITED STATES PATENT OFFICE
2,412,442
REGULATOR SYSTEM
Frederick E. Crever, Scotia, N. Y., and Leonard C.
Calder, Catonsville, Md, assignors to General
Electric Company, a corporation of New York
Application July 1, 1943, Serial No. 493,084
9 Claims. (Cl. 172-246)
1
This invention relates to regulator systems and
more particularly to improvements in wattless
current regulator systems for alternating-current
circuits.
‘
2
ies between constant power factor and constant
reactive kva.
The invention will be better understood'from '
' the following description taken in connection with
It is 'often desirable to be able to control auto- _
the accompanying drawings and its scope will
be pointed out in the appended claims.
In the drawings Fig. 1 illustrates diagrammat
ically an embodiment of the invention, Figs. 2, 3,
to the active component of the current so as to
4, 5 and 6 are vector diagrams for explaining the
maintain constant power factor for various loads 10 operation of the invention, and Figs. 7 and 8 are
on the circuit. At other times it may be desir
detailed views of modi?cations of the invention.
matically the wattless current in an alternating
current circuit. For example, it is sometimes de
sirable to vary the wattless current in proportion
able to maintain constant wattless current or re
Referring now to the drawings and more par
active power for wide variations in actual load
ticularly to Fig. 1, there is shown therein a three
or total current in the circuit. Under still other
phase alternating-current power circuit having
conditions it may be desirable to combine these 15 conductors I, 2 and 3 and it is assumed that the
two types of regulation so that under certain load
phase sequence of this circuit is I--2—-3. Con
conditions the reactive power is held constant,
nected to the circuit is an apparatus for causing
whereas under other load conditions the power
variable amounts of active and wattless currents
factor is maintained constant and for intermedi
to ?ow in the circuit. This means is shown by
ate loads both the power factor and the reactive 20 way of example as a synchronous motor 4 hav
power change. An example of the latter case is
ing a ?eld winding '5. This ?eld winding is ener- I
a synchronous motor which is subjected to con
gized from a suitable source of direct current such-v
tinually changing wide load variations. Such
as from the supply circuit '6 through a switch ‘I
operation is often encountered on electric shov
which is arranged to connect the ?eld winding
els where the synchronous motor is the main 25 across a discharge resistor 8 when the ?eld cir
power supply means of the shovel and usually
cuit is opened. The excitation of the machine
drives a Ward-Leonard set or its equivalent. By
4 is controlled in any suitable manner such as
controlling the excitation of such a motor ac
by a buck and boost generator 9 connected‘ in
cording to the latter type of regulation it can
80 series with the ?eld winding 5. This machine
at no load be made to draw a de?nite amount of
is shown by way of example as an amplidyne
lagging reactive kva. and as the load increases the
generator having a pair of short circuited brushes
reactive lagging kva. decreases so that the power
I0 for providing the main armature reaction ex
factor increases for two reasons, namely, the in
citation of the machine and being provided with
crease in the active component of the current and
series compensating field windings il in circuit
the decrease in the reactive component of the
with its load brushes !2. In addition, the ma
current until at a predetermined value of load
chine is provided with an anti-hunt winding I3.
the power factor is unity and as the load increases
and a pair of buck and boost control windings i4
further the reactive current reverses and be
and i 5. In order to secure proper anti-hunt ac-:
comes leading so that the power factor decreases 40 tion of the winding i 3 it is energized only during
but in the leading direction. Such control sub
stantially eliminates fluctuations in voltage on
changes in voltage of the amplidyne-generator
by connecting it across this generator through a
the alternating-current power supply system as a
result of variations in load on the synchronous
stabilizing transformer it.
,
For energizing the buck. and boost windings It
and It di?erentially in accordance with electri
An object of the invention is to provide a new
cal conditions in the main power circuit these
and improved electrical regulator.
windings are energized in accordance with both
Another object of the invention is to provide a
the voltage and the current of the main power
new and improved wattless current regulator for
circuit through individual recti?ers 17 and iii.
alternating-current circuits.
50 These recti?ers have input terminals which are
A further object of the invention is to provide
connected in series across the secondary Wind
motor.
.
.
'
an adjustalbe regulator which can hold either
constant power factor or constant reactive kva.
or a schedule of power factors depending upon
the load so as to give a characteristic which var 55
ing of a transformer iii by means of conductors
to and 2! and a jumper 22. The transformer 59
is excited in accordance with the voltage of the
main power circuit and. as shown, it is connected
2,412,442
3
4
4
.
away from the mid-tap. This will produce a
change in the ‘vector diagram, as shown in Fig. 5.
The shifting of the point of connection of the
resistor 24 with the secondary winding of the
transformer l9 is‘equivalent to retarding the
between the line conductors I and 2 through a ‘
conventional potential transformer 23.
‘The current response is obtained by creating '
a voltage drop in an impedance which corresponds
in magnitude and phase with the current in the
main circuit and inserting this voltage drop be
vphase of the current.
tween the junction of the input terminals of the
recti?ers, namely, thejumper 22, and an inter
_
~mediate point on the secondary winding of the
transformer IS. The impedance is shown by way 10
of example as a resistor 24 and the voltage drop
in this resistor is obtained by circulating a cur
rent in it which is the vector difference between
the currents in lines 2 and 3 in the main circuit,
this vector dl?erence being obtained by current
transformers 25 and 26 whose secondary wind
ings are connected across the resistor 24 in such
a manner that the current which ?ows in resis
tor 24 is the vector difference between the cur
That is to say, the ener
gizations of the two control ?eld windings l4 and
i5 will only be equal when the current in the
resistor 24 has been retarded in phase with re
spect to the angle it had in Fig. 4. Thus, in Fig.
5 the tap connection has been shifted to such
an extent that unity power factor operation will
result when the voltage drop across the resistor
24 is displaced thirty degrees from the position
shown in Fig. 4 and it will be seen that this cor.
responds to the angular relationship illustrated
in Fig. 3.
If now the load on the synchronous
motor decreases, the regulator automatically
holds the current to such a magnitude and phase
~20 that the energizations of the buck and boost
rents in the two secondary windings.
windings are virtually equal so that the vector
For adjusting the characteristics of the regu
representing the voltage across the resistor 24
lator the intermediate point in the secondary
has its locus on the perpendicular bisector of the
winding of ‘the transformer I9 to which the re
voltage vector [-2 with the result that the. cur
sistor 24 is connected is made adjustable by means '
rent will become more and more lagging; in other
of a plurality of taps in this winding which ter
words, the power factor will decrease in the lag
minate in tap contacts 21' which are selectively
ging direction until at no load the voltage drop
engagedby a tap switch 28.
across the ‘resistor 24 will be at right angles to
The’operation of Fig. -1 can best be understood
the unity power factor voltage drop indicating
by reference to, the vector diagrams. Fig. 2 shows
the vector relations between the line to line volt 30 that a de?nite amount of zero power factor lag
ging wattless current will be maintained in the
ages and phase currents of the main power cir
synchronous motor at no load. For increases in
cuit during unity power factor conditions and
load above the unity power factor point the power
shows that the vector difference between I3, cor
responding to. the current in conductor 3, and I2, ~ factor will become leading, as shown in Fig. 5.
Another way of representing the operation of
corresponding to the current in conductor 2, is
the regulator is shown in Fig. 6 in which the
thirty degrees out of quadrature with the voltage
horizontal vector Vrepresents the voltage of the
between lines land 2.
,
supply circuit and the parallel dashed sloping
As the vector di?erence current ?ows through
lines represent the loci of the current in the main
resistor '24, the voltage drop in'24 will be in phase
with this resultant current so that Fig. 3 shows 40 supply circuit for different settings of the tap
the relation between the input voltages of the - switch 28. The sloping dashed line passing
through the common origin zero of the voltage
and current vectors represents the operation
when the tap switch is on the mid-tap of the
ondary winding of the transformer 19. As will be
seen, the voltage ‘applied to the boosting ?eld as U! secondary winding of the transformer l9 and as
will be seen vthis represents a condition of con
I5 is greater than the voltage applied to the buck
stant power factor operation, the power factor
ing ?eld l4 so that the amplidyne-generator will
recti?ers I1 and I8 when tap switch 28 is con
nected to the mid-tap or mid-point of the sec
being thirty degrees leading. As the tap switch
is moved‘ to the right, as shown in Fig. 1, the
will continue until the inequality in voltage ap L O dashed line will be displaced perpendicular to it
self and downwardly, as shown in Fig. 6, thereby
plied to the two control ?eld windings is virtually
causing the phase of the current to vary between
eliminated and,'as shown in Fig. 4, this will occur
. ninety-degree lagging at no load and unity power
when the voltage drop in the resistor 26 is vir
factor‘at an intermediate value of load, this in
tually at right angles to the line voltage com
ponent of the energization of the rectifiers Ibe 55 crease in power factor being accompanied by
simultaneous increases in load component ‘of the
cause then the voltages across the two recti?ers '
boost the excitation of the synchronous motor,
thus advancing the phase of its current. This
will be equal. As will be seen from a comparison
of Figs. 3 and 4, this represents an advance in
phase of the current by thirty degrees so that
with the particular setting of the regulator shown
in the drawing it will automatically tend to hold
thirty-degree or .866 leading power factor of the
synchronous motor 4. Thus, as long as the cur
A rent difference stays at right angles to the volt
age, the two voltages applied to the recti?ers are
equal so that the current may increase and de
crease along thevertical line shown in Fig. 4
current and decreases in ‘lagging wattless com
ponent of the current. As the load increases fur
ther, the power factor becomes leading and de
creases from unity.
-
The angle a between the sloping dashed lines
and the voltage vector may be readily adjusted
by shifting the phase of the energization of the
transformer l9 with respect to the energization
of the resistor 26. For ‘example, as shown in Fig.
7, a rotary transformer type phase shifter may
be substituted for the potential transformer 29.
This device may consist of a polyphase stator
without unbalancing the regulator. If, however,
whose terminals are connected to the lines i, 2
vthe current departs from the thirty-degree lead
ing power factor, there will be a differential exci 70 and 3 and-a single-phase rotor whose terminals
tation of the amplidyne-generator and this will
are connected to the primary winding of the
transformer E9. The stator produces a rotating
be in such direction as to restore the balance or
magnetic ?eld which induces a voltage in the
equality of the energization of the two control
rotor and the phase of this voltage with respect
?eld windings l4 and I5.’
‘
Assume now that the tap switch 28 is moved 75 to any one of the phase or linentc-lins r-itages
5
2,412,442
at
t3
of the supply circuit may readily be adjusted by
terial whether the phase of the supply voltage or
adjusting the angular relation of the rotor to
the stator. As mentioned above, such angular
adjustment will adjust the angle of the parallel
current loci with respect to the voltage vector V
in Fig. 6.
It will be observed that in Figs. 3 and 4 the
voltage applied to the boost ?eld winding I5 is
proportional to the vector difference between two
the phase of the supply current to the regulator
is shifted, it will be obvious that the phase shifter
29 can be used in the current circuit for supply
ing the resistor 24 as well as in the potential cir-'
unit for supplying the transformer 19.
It is interesting to note that if the phase shifter
is operated so as to rotate the current loci in
Fig. 6 until they are parallel to the voltage vec
alternating voltages, these being respectively half 10 tor and if the tap switch 28 is operated from its
the voltage of the secondary winding of trans
former l9 and the voltage drop in the resistor 24,
whereas the voltage applied to the buck ?eld
winding 14 is proportional to the vector sum
of two alternating voltages, these being respec 15
mid-position so as to displace these loci from the
voltage vector, then the regulator will act to hold
constant reactive power with variations in load
because the quadrature component of the cur
rent will then necessarily be constant.
While there have been shown and described
particular embodiments of this invention, it will
be obvious to those skilled in the art that vari
tively the other half of the voltage of the sec
ondary winding of transformer 59 and the volt
age drop in resistor 24. However, this is not an
essential feature of the invention and it will be
ous changes and modi?cations can be made
obvious that the operation would be just the 20 therein without departing from the invention,
same if the phase of the voltage drop in the re
and therefore, it is aimed in the appended claims
sistor 24 were reversed by reversing its connec
to cover all such changes and modi?cations as
tions or the phase of the voltage of the secondary
fall within the true spirit and scope of the in
winding of transformer 19 were reversed by re
vention.
versing its connections, although in that case 25
What we claim as new and desire to secure by
the voltage applied to the boost ?eld would then
Letters Patent of the United States is:
correspond to the vector sum of two voltages
1. In combination, a three-phase alternating
and the voltage applied to the buck ?eld would
burrent circuit, a synchronous dynamo-electric
correspond to the vector difference of two volt
machine connected thereto, excitation controlling
ages. Furthermore, if the secondary winding of 30 means for said synchronous machine including a
transformer H! were divided into two equal coils
pair of differentially acting control windings, in
so that their relative series connections could be
dividual recti?ers for each of said control wind
reversed, the voltages applied to the buck and
ings, said recti?ers having a1ternating~current in
boost coils could both be proportional to the vec
put terminals, a third winding across which the
tor sum of two voltages or could both be pro
alternatingwurrent input terminals of said rec
portional to the vector di?erence of two voltages.
ti?ers are connected in series, means for exciting
Furthermore, the invention is not limited to
said third winding in accordance with the volt
the use of separate buck and boost ?eld coils and
age of said circuit, and means for inserting an
the outputs of the rectifiers H and I8 can be '
alternating voltage responsive in magnitude and
pa ssed through associated resistors 38 and 3| and 40 phase to the current in said circuit between the
a combined buck
boost field winding could
junction of the input terminals of said recti?ers
be connected to be responsive to the diiference be
and an intermediate point on said third winding.
tween the voltage drops across these resistors by
2. In combination, a three~phase alternating
connecting it across the two resistors in series,
current circuit, a synchronous dynamo-electric
as shown in Fig. 8. In this manner when the 45 machine connected thereto, excitation control
circuit isbalanced, as shown in Fig. 4. the volt
ling means for said synchronous machine includ
age drops in resistors 30 and Si would be equal so
ing a pair of differentially acting control wind
that the energization of the combined buck and
ings, individual recti?ers for each of said control
‘boost ?eld winding would be zero. As the voltage
windings, said recti?ers having alternating-cur
applied to one recti?er predominated that of the 50 rent input terminals, a third winding across
other, the voltage drops in the resistors
and
' which the ‘alternating-current input terminals of
Si would be unequal so that a current would ?ow
3:M rec-ti?ers are connected in series, means for
through the combined buck and boost ?eld Wind
excning said third winding in accordance with
ing in a direction corresponding to whichever
the voltage of said circuit, means for inserting an
voltage was the larger.
alternating voltage responsive in magnitude and
It will be noted from Fig. 2 that at unity power
La the current in said circuit between the
phase t"factor of the main circuit the current. in line
junction of the input terminals of said recti?ers'
conductor 3 is at right angles to the line-to-line
and an int point on said third. winding,
voltage between‘ conductors 2. Consequently, if
and means for s lfting the position of said in
current transformer 25 were omitted from Fig. 1 60 termediate point.
the system would automatically maintain unity
power factor with the tap switch 28 on the mid
tap, as shown in the drawings._ In other words,
Fig. 1i would then be representative of operating
3. In combination, a three-phase alternating
current circuit, a synchronous dynamo~electric
machine connected thereto, excitation controlling
means for said synchronous machine including a
conditions when the vertical resistance voltage (35 pair of differentially acting control windings, in
drop vector was produced by the current I3 alone
dlvidual rerii?ers for each of said control wind
flowing in resistor 2E and as this voltage would
ings, said rectiners having alternating-current
be at right angles to the voltage E2-1 at unity
input terminals, a third winding acl oss
the
power factor the system would be balanced at
alternating-“current input terminals of said recti
this power factor.
70 iiers are connected in series, means for exciting
. When the phase shifter 29 is used it is, of
said "third winding in accordance with the volt
course, unnecessary to use more than one cur
age of said circuit, means for inserting an alter
rent transformer» as the phase shifter can be used
hating voltage responsive in magnitude and phase
to produce the desired angular relation between
to the current in said circuit between the June
the current and voltage vectors. As it is imma
tion of the input terminals of said recti?ers and
9,412,442
7
an intermediate point on said third winding, and
7. Electric circuit regulating apparatus com
prising in combination, an alternating current cir
means for shifting the phase relation of the excitation of said third winding with respect to the
cuit, apparatus connected to said circuit for effect
voltage of said circuit.
ing the flow in said circuit and in said apparatus
‘
‘
‘4. In combination, an alternating current pow
of a variable magnitude and variable phase cur
rent, control means for said apparatus including '
er circuit, a dynamo-electric machine connected
thereto, regulating means responsive to the volt
a pair of differentially acting control windings
age and current of said machine for automatically
and a pair of recti?ers connected for supplying.
varying the excitation of said machine to main
unidirectional current thereto, and means respon
tain a predetermined phase relationship between 10 sive to the phase relationship and magnitude of
said voltage and said current, said regulating
current and voltage in said circuit for energizing
means including a voltage responsive transformer
said rectifiers including a ?rst transformer re
having a primary winding energized from said
sponsive to magnitude and phase of circuit volt
power circuit, a secondary winding for said volt
age and a second transformer responsive to mag
age transformer having an intermediate tapped
nitude and phase ‘of circuit current, said ?rst
point for obtaining two control potentials oppo
transformer having an adjustable voltage sec
ondary winding.
_
'
site in phase, a current responsive transformer
for obtaining a voltage proportional to power cir
8. Electric circuit regulating apparatus com
cuit current, means for adding said current pro
prising in combination, an alternating current
portional voltage to‘ said control potentials, and
circuit, apparatus connected to said circuit for
means for varying the position of said interme
effecting the now in said circuit and in said ap
diate point on said voltage responsive transformer
paratus of a variable magnitude and ‘variable
to unbalance the magnitude or‘ said control po
phase current, control means for said apparatus
including a pair of differentially acting control
tentials.
5. In combination, a three phase alternating 25 windings and a pair of recti?ers connected for
current ‘circuit, a synchronous dynamo-electric
supplying unidirectional current thereto, means
responsive to the phase relationship and magni
machine connected thereto, excitation control
- ling means for said synchronous machine includ
ing a reversible polarity control winding, 3, pair 4
tude of current and voltage in said circuit for '
energizing said recti?ers‘including a ?rst trans
of recti?ers of opposed polarity for energizing 30 former responsive to magnitude and phase of cir
said control winding, said recti?ers having alter
cuit voltage and a second transformer respon
nating current input terminals, a second Wind
sive to magnitude and phase of circuit current,
ing across which the alternating current input
and means interposed between said second trans
terminals of said rectiflers are connected in se
former and said electric circuit for shifting the
ries, means for exciting said second winding in
phase relationship between said circuit voltage
accordance with the voltage of said circuit, and _ and said second transformer output voltage.
means for inserting an alternating voltage re
9. Electric circuit regulating apparatus com“
sponsive in magnitude and phase to the current
prising in combination, an alternating current
in said circuit between the junction of the input
circuit, apparatus connected to said circuit for
terminals of ‘said recti?ers and an intermediate 40 e?‘ecting the ?ow in- said circuit and in said ap
point on said second winding.
'
paratus of a variable magnitude and variable
6. In combination, a three phase alternating
phase current, control means for said apparatus
current circuit, a synchronous ‘dynamo-electric
including an electrically reversible control wind
machine connected thereto, excitation control
ing and recti?er means connected thereto for en
ling means for said synchronous machine includ
ergizing said winding with direct current of re-'
ing a reversible pdlarity control winding, a pair
versible polarity, means responsive to the phase
of recti?ers of opposed polarity for energizing
relationship and magnitude of current and‘volt
said control winding, said recti?ers having alter
age of said circuit for energizing said recti?er
nating current input terminals, a second winding
means including a ?rst transformer responsive
across which the alternating current input termi
to magnitude and phase of circuit voltage and a
second transformer responsive to magnitude and
nals of said recti?ers are connected in series,
means for exciting said second winding in ac
phase of circuit current, and means interposed ,
cordance with the voltage of said circuit, means
betweensaid electric circuit and‘ said second
for inserting an alternating voltage responsive in , transformer for shifting the phase relationship
magnitude and phase to the current'in said cir
between said circuit voltage and second trans
cuit between the junction of the input terminals
former output voltage.
of said recti?ers and an adjustable intermediate
point on said second winding, and means for
FREDERICK E. CREVER.
shifting the phase relation of the excitation of
LEONARD C. CALDER.
said second winding with respect to the voltage 60
of said circuit.
‘
'
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