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Патент USA US3026476

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March 20, 1962
K. F. FRIEDRICH
3,026,466
ELECTRIC POWER TRANSLATION SYSTEM
Filed Nov. 2l, 1958
2 Sheets-Sheei'l 1
March 20, 1962
K. F. FRIEDRICH
3,026,466
ELECTRIC POWER TRANSLATION SYSTEM
Filed Nov. 2l, 1958
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INVENTOR
Kevin E Friedrich4
United States Patent Office
ßßïhßäh
Patented Mar. 20, 19ë2
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2
3,026,466
desirable in a translation system of the type described,
which is used to convert a polyphase alternating current
to a unidirectional current, that the alternating current
ELECTRIC POWER TRANSLATION SYSTEM
Kevin F. Friedrich, Sharon, Pa., assigner to Westinghouse
applied to associated asymmetrically conducting devices
Electric Corporation, East Pittsburgh, Pa., a corpora
tion of Pennsylvania
include a larger plurality of phases in order to obtain a
smoother unidirectional current at the output of the trans
Filed Nov. 21, 1958, Ser. No. 775,431
13 Claims. (Cl. 321-5)
lation system. Further, it is desirable that the phase
angle shift required in phase shifting transformers in
This invention relates to electric power translation sys
cluded in a translation system of the type described be
tems of the type in which a plurality of asymmetrically
held to a minimum.
It is an object of this invention to provide a new and
con-ducting devices are used to interchange power in one
direction or the other ‘between a first polyphase system
improved electric power translation system.
and a second system which may be either a direct current
It is another object of this invention to provide a new
and improved connection arrangement between a trans
former means and a plurality of asymmetrically-connect
ing devices in a translation system for electric power.
A further object of this invention is to providea new
and improved electric power translation system which
system or an alternating current system having a fre
quency which is different from the first polyphase system,
In certain types of conventional electric power trans
lation systems, such as rectifier circuits, including a plu
. rality of rectifierV units connected in parallel, it is desir
able to provide a relatively large number of rectifier phase
voltages in order to obtain more desirable operating
‘N
includes a plurality of transformers and associated phase
shifting means with the plurality of transformers ar
characteristics. For example, one advantage of providing 20 ranged to reduce the phase angle shift required in 'the
a large number of phases in such a system is that asso
associated phase shifting means.
ciated power generating equipment, `such as generators,
A more specific object of this invention is to provide
in an electrical power system need be effectively derated
an electric power translation system having a multiple
to a lesser extent. There are several conventional meth
phase output and including a plurality of transformers
ods for increasing or multiplying the number of phases 25 divided into pairs with the primary windings of each
in an overall rectifier system, One method commonly
pair arranged to introduce a phase angle shift into the
employed is to provide phase shifting means, such as
output voltage of each of said transformers in oppo
phase shifting transformers, which are connected in cir
site directions to reduce the phase angle shifts required
cuit relation With associated rectifier transformers to in
in associated phase shifting transformers.
troduce different phase shifts into the output voltages 30 A final object of this invention is to reduce the phase
of each of a plurality of parallel connected transformers
angle shift of the phase shifting means in an electric
to thereby increase the number of phases in the overall
power translation system having a relatively large number
rectifier system.
'
'
»
of phases at the output without requiring a tertiary wind
The required phase angle shift introduced by each of
the phase shifting transformers in a rectifier system of
the type described may be quite large in a particular
application and the phase shifting transformers in such
mg on the transformers included in the translation system.
ther objects of the invention will in part be obvious
and will in part appear hereinafter.
For a fuller understanding of the nature and objects
of the invention, reference should be had to the follow
in physical size and rather difficult to design. In order
ing detailed description, 'taken in connection with the
to reduce the phase angle shift required in certain appli 40 accompanying drawing, in which:
applications have the disadvantages of being quite large
cations, one conventional method involves the use of a
FIG. l is a schematic diagram in block form of an
plurality of rectifier transformers half of which inclu-de
delta connected primary windings and half 0f which
electric power translation system illustrating one embodi
ment of the invention;
include Y connected primary windings to reduce the
FIG. 2 is a schematic diagram of parts of the apparatus
required phase angle shift in the associated phase shift 45 shown in PIG. l in block form; and
ing transformers. A disadvantage ofthe latter method
FIG. 3 is a schematic diagram illustrating an alternate
is that in certain conventional rectifier circuits of this
form of the interphase reactance means shown in FIG. 2.
type, it is necessary to provide a -delta connected tertiary
.Referring now to the drawings and FIG. l in par
winding on a rec'tiñer'transformer which includes a Y con
50 ticular, there is shown in general, an electric power trans
nected primary winding. The necessity for a tertiary
lation system illustrating one embodiment ofthe inven
winding on a transformer increases the equivalent k.v.a.
tion. More specifically, there is illustrated an electric
rating and the associated losses of such a rectifier trans
power translation system of the type in which power
former.
is taken from a three phase power supply system includ
An example of a rectifier circuit in which the rectifier
ing the power leads Ll, L2 and L3 and is transmitted
transformer must include a delta connected primary
through a plurality of asymmetrically-connecting devices
winding or include a tertiary winding provided for neutral
to a unidirectional current circuit having power leads
stabilization is disclosed in U.S. Patent No. 2,825,022,
D1 and D2, to which is` connected a load lut). The in
issued Feb. 25, 1958, on application of l. L. Boyer et al.
vention will be described as if the power is transferred
and assigned to the assignee of the present application. 60 from the three phase power leads Ll, L2 and L3 to the
The rectifier circuit disclosed in said patent is of a type
unidirectional current power leads Dl and D2, but it
which is uniquely adapted for use with certain asymmet
is to be understood that by the use of well known in
rically-'conducting devices, such as semiconductor recti
verter control connections, the direction of power ñow
fiers and large ignitrons, in which the rating is deter
could be reversed» The unidirectional current power
mined, more by the peak current rather than by the 65 leads D1 and D2 will be described as if they were a di
average current carried by each of said devices. In
rect current power system which receives power from
order to take greater advantage of the current carrying
the three phase power system at L1, L2 and L3, but it is
capacity of such devices, it is desirable that a rectifier
to be understood that unidirectional current power leads
circuit or system be provided in which each of said devices
could be either the anode terminal circuit of one phase
has a lower peak current and also conducts for longer
(or the phase) of a second different frequency alternat
periods during each cycle of the alternating current elec
tric power _interchanged in such a system. ' It is yalso
'
ing current system which receives power from or which
transmits power to the three-phase power system at L1,
spaanse
3
4
L2 and L3, provided that suitable rectifier controlling
plurality of groups 50, each of said groups including six
semiconductor rectifying devices S1 through S6, which
means are provided.
Y
The electric power translation system shown in FIG.
are of a type in which the rating is determined more
1, more specifically the rectifier. system, comprises a plu
rality of phase shifting means, a plurality of associated
by the peak current than by the average current carried
rectifier transformers and a plurality of groups of asym
metrically-conducting devices connected in circuit rela
tion to provide a unidirectional current output based on
It is to be noted that each pair of the rectifier trans
formers 40 and 141i introduces a phase angle shift into
by each of said rectifier devices.
Y
the output voltages of the respective rectifier transform
ers which decreases or reduces the required phase angle
The translation system shown in FIG. 1 includes 10 shift in the associated phase shifting means 30, 32, 34,
36, 38 and 42. For example, if the rectifier transform
twelve phase shifting means each arranged to introduce
er 40 connected to the phase shifting means 3d did not
apredetermined phase angle shift >between the voltage
72 phase rectifier operation.
include a phase shi-ft or phase rotation of substantially
+15 °, the phase shifting means 30 connected between
and B3, respectively, and the voltage applied at the in 15 the transformer 40 and the power leads L1, L2 and VL3»
would have to be designed for a phase shift of ysubstan
put of each of the associated rectifier transformers.
Each of the phase shifting means 30 introduces a phase
tially +271/2" rather than l21/2° as shown.Vv The man
ner in which the phase angle shift is` incorporated into
angle shift of substantially -1-121/2", and the shifting
each ofthe rectifier transformers 40 and 140 of a pre
means 32, 34, 36, 38 and `42 each introducesl a phase
angle shift of +71/2°, -[-21/2-°, '-2'1/2° and ---l21/2°, re 20 determined angle which is in opposite directions for the
transformers 4t? and 1.40, respectively, relative to the
spectively. The twelve rectifier transformers associated
voltage at the three-phase power leads L1, L2 and L3 I
with the twelve phase shifting means just described are
will be explained hereinafter in detail.
divided into two groups of six transformers 40, each in
In summary, the electric power translation system
troducing an additional phase angle shift between the
voltage at the input of each of said transformers and the 25 shown in FIG. 1 includes phase shifting means and a
plurality of rectifier transformers for applying to associ
voltage at the output olf each of said transformers of
ated groups of asymmetrically-connecting devices, 72 recti
substantially +l5° with respect to the voltage at the
at the three-phase power leads Ll, L2 _and L3r which are
connected to the corresponding bus conductors Bil, B2 '
fier phase voltages which are symmetrically displaced from
` three-phase power leads L1,.L2 and L3. The other six
each other by substantially five electrical degrees, each
rectifier transformers 140 each introduces an additional
phase'angle shift of substantially ,-15 ° with respectV to 30 pair of the rectifier transformers cooperating with the
the voltage at the three-phase power leads L1, L2 and
L3.
v
associated phase shifting means to provide two six-phase
output voltages which are separated kfrom each other by
substantially 30° or, in other words, each pair of recti
The twelve rectifier'transformers, which Vincludes the
fier transformers providing a twelve-phase output voltage.
six transformers 140 and the six transformers di), may
be divided into six pairs of transformers, each including 35 The twelve-phase _output voltages of the respective pairs
of transformers are’then displaced in phase relation from
a transformer 40 and a transformer 14€! which are both
each other by predetermined phase angles as indicated
connected to associated phase shifting means having the
by the various phase shifting means shown in FIG. l to
y same phase angle shift associated with said phase shift
produce 72 rectifier phasefvoltages which are finally ap
ing means. For example, there is a transformer 4f! and
a transformer 140 each connected to a phase shifting 40 plied to the plurality of rgroups 50' of the semiconductor
means 30, which introduces a phase angle shift of 121/2 °
rectifying devices. As stated previously, the required
with respect to the voltage at the three-phase power leads
phase angle shift introduced by each of the phase shift
L1, L2 and L3 at the input of the associated transformer.
ing means 30 through 42 >is `reduced by the inherent phase
The other phase shifting means 32, 34, 36, 38 Vand d2
shifting characteristic of each of the rectifier transformers
’
'
~
and the associated rectifier transformers Mia-nd` 1,40 may 45 4f) and-140, respectively. '
be similarly divided into pairs. The rectifier transform
er‘4t) connected to the phase shifting means 30 produces
at the output rectifier leads Rl’ through R6', six recti
fier phase voltages which are applied to the associated l
group 50 of the semiconductor rectifying '-'devices' S1 50
Referringnow to FIG. 2, there -is illustrated in detail
the phase shifting means 42 Iand 30l Iand the associated
rectifier transformers 140 and 40 respectively. As shown,
the rectifier transformers y14€) and 40 are each intercon
nected withV an associated group 150 of ignitron tubes
through S6, respectively, for providing a first six-phase
Tl through T6 which may be substituted «for the groups
Sil shown in FIG. 1 and which may be taken to be broadly
output at .the unidirectional power leads D1 and D2.
representative of six separate single phase asymmetrically
Theass'ociated rectifier transformer 140` also connected
»to the phase shifting‘means 3f? also produces six -rectifier
conducting devices »of a type in which the rating of each
phase voltages at its output which are displaced in phase 55 lde’gice is determined more by its peak current thanby its
vfrom the output of the associated rectifier transformer
average current. Each of the ignitron tubes T 1 through
" V40 by an angle of substantially 30° because of the rela
T6 comprises .a main anode '72, a grid ’74 'and ignitor 76 e
.tive phase angle shifts of opposite directions with re
and a mercury orfotherV vaporizable cathode' pool 7S.
The six cathode leads ofthetubes T1 through T6 are
troduced by the pair of transformers 40 and 14@ which 60 'each connected to the positive conductor D?. of the direct
' Spect to the power leads L1, L2 and L3 which are in
' are connected to the’phase shifting means 30. VSimi
larly, the rectifier transformer ile-ti` connected to the
phase shifting means 42 produces at the rectifier leads
R1 through R6, six Vrectifier phase voltages which are
currentV bus.
The six anode‘leads of the tubes T1 to
T6 comprise six rectifier leads R1 throughy R6 respectively, ì "
the leads and the tubes being numbered in accordance
-with the sequence of the phases in a Vsix phase rectifier
applied to another associated group Sti and which are 65 arrangement.
The phase shifting means e2 and 30 each comprises a
displaced in a phase substantially 30° from the output
.voltageso'f the other rectifier transformer 40 Vof the pair ’ .
conventional, hexagonally connected autotransformer hav
of. transformers-¿ffl and 14d which .are Vboth connected 7 ing input terminals A, B and C connectedto the three
phase power leads L1, L2, and L3, respectively, through:
to a phase shifting means 42. The other rectifier trans
the bus connectors B1,»B2 and B3, respectively. The
i' V.forrners‘dfì and 140 and'their’associated phase shift
ing ` means 32,"` 34,66 and 38, respectively, each pro
.
' vides six rectifier’phase voltages to the unidirectional
f îïpower leads 'Dfi and D2 which are symmetrically 'dis
1» placed in 'phase' from V_the outputs'iofV the Vother vrectifier .
. transformers to provide total ot 72 rectifier phasesjtoi the:
-output terminals Pill, P2 and' P3Vofr. the phase shifting'
:transformer ¿ft-2A are connected to they input terminals H1,V
‘H2 and H3, respectively, of the associated rectifier'trans'-V
former effi. »As Vwell known in the art',` the relative por
tions or turns of the phase windings of Athe phase shifting
noaa-16e
6
transformers 42 and 30 may be varied to obtain a phase
langle shift between the voltage applied at the input termi
nals and the voltage of the output terminals of said phase
shifting transformers. For example, the output voltages
of the phase shifting transformers 42 and 30 are displaced
in phase from the input voltages by phase angles of
+121Á2° and _l21/2°, respectively. The phase shifting
transformer 30 is similar to the phase shifting trans
former 42 except that the corresponding references `are
permit the parallel operation of a plurality of rectifier
phases.
v
ì
A
y
ì
As explained previously, each pair of rectifier trans
formers is connected to a phase angle transformer means
having the same phase angle shift and is arranged to in
clude a first transformer, shown in FIG. 2 as the trans
former 4f), and a second transformer, shown in FIG. 2
as the transformer 140. For example, as shown in FIG.
l, a transformer 46 and a transformer 140 are connected
primed and the windings arranged to produce a phase 10 to an associated phase shifting means 30 having the same
angle shift in the opposite direction to the direction of
phase angle shift, which is substantially -}-l21/2 °. Each
the phase angle shift introduced by the phase shifting
pair Iof the transformers 40 and 140v has the hexagonally
transformer 42. The other phase shifting transformers ~ connected or interconnected primary windings 62 and 162,
or means 32, 34, 36 and 38 are similar to the phase shift
respectively, arranged to shift the input voltage applied at
ing transformers 42 and 30 except lfor the relative por 15 each of said transformers 4by a predetermined phase angle,
tions or turns of each phase winding of said phase shift
which is illustrated as being substantially 15°, in opposite
ing transformers and the corresponding phase angle shift
directions with respect to the voltage at the power leads
produced by each of said phase shifting transformers, as
L1, L2 and L3. When the phase angle of the voltages
shown in FIG. 1.
The rectifier transformers 140 and 40 include the hex
applied at the inputs of a pair of transformers 4f) and 140
is the same, then the hexagonally connected primary wind
agonally connected or interconnected primary windings
162 -and 62, respectively. The input terminals H1, H2
ings of said transformers are arranged so that the six
and H3 and H1', H2' and H3’ of the transformers 140
and 40, respectively, are connected to the output termi
from the voltage at the power leads L1, L2 and L3 by a
40, respectively. For example, the secondary winding
the phase windings in the primary windings 62 and 162,
phase output voltage of each transformer is displaced
predetermined angle, which is substantially 15°, in op
nals of the associated phase shifting transformers 42 and
posite directions. Therefore, the two six-phase voltages
30, respectively. Each of the rectifier transformers 40
of each pair of the transformers 40 and 140 are displaced
and ‘140 includes three secondary windings 6_3, 1_4
from each other by a total phase angle of substantially
and 2_5 and 6'_3', 1’_4’ and 2’_5’, respectively.
13° to produce a total of l2 rectifier phase voltages dis
Each of said secondary windings includes the mid-tap
placed from each other by substantially 30°. It is to be
leads M1, M2 and M3 and M1', M2’ and M3', respec 30 noted that the physical construction of the rectifier trans
tively. Each of the secondary windings is responsive to
formers 40 and 140 is substantially the same and that the
the main portion of the associated phase winding of the
only difference between the transformers lies in the con
primary winding of each of the transformers 140 and
nections of the several portions which make up each of
6_3 is responsive to the main portion of the phase wind 35 respectively, of said transformers. Therefore, the com
ing between the terminals H‘1 and H2 of the associated
mutating reactance of each of the transformers 40 and
primary winding 162.
The connections of the secondary windings of the
140 is substantially the same which eliminates the neces
sity of matching the reactances of delta and Y rectifier
transformer 140 will be described in detail and it is to
transformers which are often connected in parallel in con
be understood that the connections of the secondary wind 40 ventional rectifier circuits.
ings of the transformer 40 are similar except that the
It is to be noted that the interphase reactance means 70
reference numbers are primed. The secondary windings
and 70' are necessary since the rectifier connections de
6_3, 1_4 and 2_5 are connected to the associated
scribed above are such that different rectifier phases,
ignitron tubes T1 through T6 in a triple diametric con
which are energized by the instantaneous voltages of the
nection. The diarnetrically opposite ends of the sec 45 three-phase power circuit at L1, L2 and L3, are operated
y ondary winding 6_3’are connected to the associated
ignitron tubes T6 and T3, respectively. Similarly,
the diametrically opposite ends of the winding 1_4 are
connected to the ignitron tubes T1 land T4 respectively,
in parallel with each other at times so as to simultaneously
' supply to or receive power from the same unidirectional
power circuit or bus.
The interphase reactances 70 and 70’ develop the in
and the ends of the winding 2_5 are connected to the 50 stantaneous voltage differences necessary to permit the
ignitron tubes T2 and T5, respectively. The voltage
between the opposite ends of each secondary winding
parallel operation of two or more rectifier phases having
output voltages which do not reach their peaks at the
same instant and yet allow independent operation of the
`> Vand its associated mid-tap are substantially 180° out of
phase. For example, the voltage between the terminal
parallel rectifier phases. The interphase reactances 70
6 and the mid-tap M1'is 180° out of phase with the volt 65 and 70’ are represented as each comprising three phase
age between the terminal 3 and the mid-tap M1. There
l `windings which would be disposed on an associated mag
fore, the secondary windings of the transformer 140 are
netic core (not shown) and connected in a star or Y
arranged to produce three biphase voltages which are
arrangement, the neutral point of the Y connected wind
displaced from eachother 'by substantially 120°. Simi
ings being connected to the negative conductor D1 in
larly, the secondary windings of the transformer 40 are 60 order to provide areturn path for the output currents
also arranged to produce three biphase voltages. The
supplied to the unidirectional current lbus at the conduc
mid-taps M1, M2 and M3 of the secondary windings
tors D1 and D2. The interphase reactance means ’70 and
70' will be designed for operation at the second harmonic
the negative conductor D1 of the direct current bus
of the fundamental frequency of the voltage at the power
through the windings 70A, 70B and 70C, respectively, 65 leads L1, L2 and-L3.
of an interphase reactance means 70 which is of three
In actual practice, the interference reactance means 70”
phase construction and Y connected withV the neutral> point
shown in FIG. 3 could be substituted for each of the
of the .Y connected interphase reactance' means 70 con
interphase reactances ‘70 and 70’. Each of the three phase
nected to the negative conductor D1. Similarly, the sec
windings of the interphase reactance 70” are divided into
ondary windings of the transformer 40 are connected at 70 two sections '70AA and 7iiAB, 70BA and 70BB, 70CA
their mid-tap leads M1’ through M3' to the negative con
and 70GB, respectively, with each pair of sections con
nected in a zig-zag arrangement to the mid-tap terminals
ductor lll-through a similar interphase reactance means
70'. The interphase reactance means 70 and 70' are
M1, M2 and M3, respectively, and with the neutral point
connected to the negative conductor D1. The interphase
each provided to absorb or develop the necessary alter
nating current voltage differences or ripple voltages to 75 reactance 70” has the advantage that in operation the
6_3, 1_4 and 2_5 respectively are each connected _to
3,026,466
s
8
able changes in the phase shifting means or transformers
inag'netomotive forces on Aeach leg of the associated ,mag-5
Y' neticrcore (not shown) due tothe unidirectional currents
which flow in the windingsof the interphase reactancel
, 70” ,are balanced or substantially add up to zero.
provided between each pair of rectifier transformers and
a polyphase‘ power system, such as the three-phase power
system indicated at L1, L2 and L3 in FIGS. 1 and 2. For
example, a 24 phase rectifier system could be provided
with two pairs of the rectifier transformers 40 and 140
The:
latter operation assumes that the unidirectional currents.
which -ii‘ow at the associated mid-tap terminals Ml, M2.
and with four associated phase shiftingV transformers, two
and M3 are substantially equal.
In general, the connections between each of the trans
-being designed for a phase angle shift of «.-l-71/2 ° and two
being designed for a phase angle shift of -71/2 ° or with
. formers 140 and 40, the associated rectifier leads R14
only two 15° phase shifting transformers. Other rec
tifier systems in multiples of twelve phases vcould be simi
through R6 and R1’ through R6', respectively, and the-ignitron tubes T1 through T6 in each of the groupsîStìi
may be described as a hexagonal or interconnected delta,
larly provided. In'general, Ythe number of phases ina
six-phase, triple diametric connection. Since'three bi--
translation system or rectifier system as disclosed would
be equal to the number of pairs of rectifier transformers.
provided times twelve assuming that suitable or appropri
ate phase shifting means were also provided.L
phase voltages are obtained at the >output of each ofthe:
transformers 40 and 140 by the latter connection which~
are separated by an angle of substantially 30° from the
As previously described, the ignitron tubes T1 through
koutputvoltageuof theassociated rectifier transformer of‘
T6 may be provided with -any‘sui'tableY _ignitor energizing.
each pair due to the difference in the connections of the
control circuit for energizing the ignitors'76‘of the sev
hexagonally connected primary windings vof >the trans
formersinfeach pair, a total of _six biphase voltages forA .20, eral tubes. As described, each of the ignitron tubes T1
through T6 constitutes a vapor-electric device having‘a
twelve phase rectifier >operation may be provided by con»
single-phase space current pathbetween an anode means
knecting each of the` diametrically opposite ends of the
and a cathode means and each vapor-electric device has
secondary windings of each pair of rectifier transformers
its own individual-cathode means, It is to be understood
40 and 140 through one-of the rectifier leads R1 to R6
vand R1’ to R6’ to one of the ignitron tubes T1 to T6 off 25 that the rectifier circuit or translation system as disclosed
could be used with any of the well known semiconductor
rectiiiers, preferably of the type in which the current
' The operation of the secondary windings 6--3,v1--4»
>each of the associated groups 150 of ignitron tubes.k
rating of the rectiñer is determined more by the peak
current than by theV average current carried by eachsemi
_and 2_5 in the transformer-,140 in the interconnected
delta, six-phase, triple diametric connection will now be
considered. Because of the diametric connection of the-y
conductor rectiñer.
n
‘
secondary windings 6--3, 1-«4 >and 2-5 of the power'
Átransformer '140‘ through the associated rectifier leads R6
and R3, R1 and R4, rand R2 and R5, respectively, to the;
In FIG. l, the asymmetrically-c'onne‘cted devices are
each shown by means of a conventional rectifier symbol
which is intended to be applicable to any kind of asym
corresponding ignitron tubes T6'and T2, T1 and T4, and
`rnetrically-conducting device. In FIG. 2, the asymmetri
T2 and T5, respectively, three'of the latter ignitron tubes . 35 cally-conducting devices are shownV as ignitron tubes. In
carrying out this invention, it is contemplated that devices
wouldpbe operating at parallel at any given instant of’
shall preferably be of a type in which the rating is deter
>each voltage cycle of the three-phase power system at Ll,
VL2 and L3. Any voltage differences, existing at the 'out
mined more by the peak current rather than by the ther
mal capacity of the asymmetrically-conducting device. ~
puts of the three ignitron tubes which are operating in
parallel at any given instant willbe absorbed by`one of at() Two examples of’such asymmetrically-conducting, devices
previously mentioned are the ignitron tube and’any one of A
the interphasereact’ances ’70' or 79". The group 15-0í of
the large number of semiconductorrectiíiers and our in
vention shall be understood as preferably including the.
._ the ignitron tubes T1 through T6 connected tothe sec
onc‘la‘ryl windings of the associated transformer '40 con
nected to the phase shiftingv means having the same phase
angle shift- as the phase shifting means connected to thel
transformer 140`of the same pair will- operate in similar
use of either one of these two types of rectiliers. Con-l
sidering the/semiconductor rectiiiers, the current rating
Áof such rectiñers is'comrncnly established by the maxi- ï
mum peak' orfault current which said devices can .with
stand. In order to obtain sufficient current capacity, such
fashion so that` at any given instant, six of the twelve
ignitron tubes vincluding the two groups 15§)"connected to
each pair >of Vrectifier transformers will be operating in
rectiiiers are often employed with a plurality of rectiiiers
` vparallel to provide effectively twelve phase rectifier opera-v ' , connected in parallel in each phase of an overall rectifier
system. Since the peak current of a translation system
tion. Since'at Vany given instant, three of the `six ignitron
as disclosed is lower than that of a conventional recti
tubes connected to each transformer operate in parallel,
fier circuit of the same type, the'number of parallel yco'n- e
each ignitron tube conducts for ’180° for each cycle of
the power supply system at L1, L2 and L3. The con
nected semiconductor rectiiiers may be reduced in appar
duction of six ignitron tubes in parallel for each' pair of>
ticular application without reducing the overall current
capacity of the complete translation system.
‘ rectifier transformers will progress ini phase sequence in
.',accor'dance `with the reference numbers of the ignitron
_
It is to be understood that single phase transformers" Y
may `be substitutedfor thel polyphase transformers'in
tubes Tlto T6. As one ignitron tube ceases to conduct
Vthe nextignitron tube will begin to conduct so that six
~ eluded in a translation system or rectifier circuits as .di’s- ~ ' '
closed in a particular application.
l
-;
,~ ,
of theV twelve-.ignitron tubes connected to each pair of
. Irectifier transformersare alwaysV conducting in parallel.
` It is to be noted that‘the rectifier transformers included
in' a translation system as disclosed combine phase shift- .
' In a >72 phase'translation system, such as the rectifier cir->
ing with phase multiplication and,voltage"transformationY
j cuit shown in FIG. 1_, this means that at any given in
andas previouslyfmentioned, the physical construction of
stant substantially 36 of the 72 asymmetrically-connectingf
each of the rectiñer transformers in a rectifier system as
`'devices shown in said system are operating in parallel. '
. disclosed isV substantially the same except lfor `the inter
`It is to be understood that a translation system as dis
connections` of the different portions of the primary wind
ings of the phasewindingsïin each primary winding“ of
' closed 'may include one or more pairs of-rectifìer trans-V
formers 40 and 140` in a particularV embodiment. VFor
example, a twelve-phase rectifier system could be pro
‘vi'ded with one pair of transformers 40 and ‘140 con
said rectifier transformers. f
.70
>fi‘iectedV directly to a three-phase power system such as
; indicated at the leads Ll.,V L2 and L3 without any as
' '-sociated phase` `shifting means being required. `Other
Y"rectifier systems includingv two or lmore pairs of >rectifier
transformers'40 and '149 could'befprovided'with suit-`
.
Y
The apparatus and circuits embodying the teachings of
the invention have 'several advantages. For example, in
’
ie
a rectifier or translation system as disclosedhaving a rela-V
tively Vlarge` number ofL phases, the required V'phase angle!VV '_ ,
shiftand’size of'therphase'shifting transformers included "
in’saîd system, compared-.with those employed inl'conven- u
adsense
.
10
9 '
tional rectifier circuits, is substantially decreased or
reduced without the necessity for additional tertiary
devices, triple diametric connection means for connecting
the diametrically opposite end connections of said sec
ondary windings of each transformer means to said
twelve-phase power leads and for connecting said devices
ybetween said unidirectional current leads and said twelve
windings on the rectifier transformers included in said
rectifier system. A second advantage relates to the con
struction of the rectifier transformer in a translation
system as disclosed. Since each phase winding of the
phase power leads, said heXagonally-connected primary
hexagonally connected primary windings of the rectifier
windings of Said transformer means being arranged to
transformers 40 and 140 includes portions of voltages
shift the six-phase output voltage of each transformer
from at least two of the three phases of the three-phase > means by a predetermined phase angle in opposite direc
power system to which the primary winding is connected, 10 tions to provide a twelve-phase output voltage at said
any unbalance in the phase voltages from the three-phase
twelve-phase leads and interphase reactance means con
system applied at the input of the rectifier transformers
nected between said mid-tap leads of said secondary wind
will be transmitted to several phase windings of said recti
ings and said unidirectional leads to permit 4half of said
ñer transformers. v The latter arrangement tends to reduce
devices to operate in parallel at all times.
unbalanced currents which might otherwise result in the 15
2. An electric power translation system comprising
different phases at the output of each rectifier transformer
three-phase power leads, unidirectional current power
and may eliminate the necessity for special load compen
leads, twelve-phase power leads, ñrst and second trans
sating circuits which would be designed to distribute the
former means connected 'between said three-phase power
load current substantially equally among the three bi
leads and said twelve-phase power leads, each vof said
phase rectiñer voltages associated with each transformer. 20 transformer means including a three-phase prim-ary wind
Otl'er advantages of a translation system as disclosed
ing hexagonally-connected to said three-phase power leads
relates to the preferred triple diametric connection of the
and three secondary windings each having a mid-tap lead
secondary windings of the rectifier transformers 40 and -
and diametrically opposite end connections for providing
140. The latter connection results in substantially 180°
la six-phase voltage output, a plurality of -vapor electric
conduction in each asymmetrically-connecting device in 25 devices each having a single-phase space current path and
the system and a lower peak current which permits more
anode means and a cathode means, each of said devices
eñicient use of asymmetrically-conducting devices of the
having its own individual cathode means, triple diametric
type in which the rating is determined more by the peak
connection means for connecting the diametrically oppo
current than by the average current carried by each of
site end connections of said secondary windings of each
said devices. The latter advantage is particularly irn 30 transformer means to said twelve-phase power leads and
-portant in the application of semiconductor rectiñer
for connecting said devices `between said unidirectional
de vices where additional rectifier devices are often required
current leads and said twelve-phase power leads, said
to provide for the higher peak current or fault current
heXagonally-connected primary windings of said trans
which occurs in conventional rectifier circuits of the same
former means being arranged to shift the six-phase out
type.
35 put voltage of each transformer means by a predetermined
It should be noted that the necessity for a tertiary wind
phase angle in opposite directions to provide a twelve
ing in certain parallel connected rectifier units in transla
phase output voltage `at said twelve-phase leads and inter
tion systems, having a relatively large number of phases, '
phase reactance means connected between said mid-tap
arises because of the problem of neutral stabilization. In
leads of said secondary windings and said unidirectional
certain types of conventional rectifier circuits, the primary 40 leads to permit half of said devices to operate in parallel
winding cannot be connected in Y since, during the opera
at all times.
tion of the rectifier system, the primary neutral might
3. An electric power translation system comprising
shift and produce erratic operation of the overall rectifier l three-phase power leads, unidirectional current power
system. For example, the asymmetrically-conducting
leads, twelve-phase power leads, first and second trans
devices might conduct for 120° or 60° instead of sub 45 former means connected between said three-phase power
stantially 180° as is normal in a triple diametric rectifier
leads and said twelve-phase power leads, each of said
circuit. The latter operation results because of changes
transformer means including a three-phase primary wind
in the voltages across particular phases of the rectifier
ing heXagonally-connected to said three-phase power leads
transformers due to shifting of the lprimary neutral and
and three secondary windings each having a mid-tap lead
the corresponding shifting of the neutral in the secondary 50 and diametrically opposite end connections for providing
Winding. VAs previously mentioned, the latter problem is
a six-phase voltage output, a plurality of mercury vapor
not present in a rectifier system as disclosed since a Y
gas tubes each having a single-phase space current path
connected primary winding is not necessary in the differ
and anode means and a cathode means, each of said tubes
ent rectifier transformers.
having
its own individual cathode means, triple diametric
Since numerous changes may be made in the above ap
connection means for connecting the diametrically oppo
l paratus and circuits, and diiîerentembodiments of the in
site end connections of said secondary windings of .each
vention may be made without departing from the spirit
transformer means to said twelve-phase power leads and
thereof, it is intended that all kthe matter contained in the
for connecting said tubes between said unidirectional cur
y foregoing description or Yshown in the accompanying
rent leads and said twelve-phase power leads ,said hexag
drawing shall be interpreted as illustrative and not in a
60
limiting sense. i
I claim as my invention:
l. An electric power translation system comprising
three-phase power leads, unidirectional current power
onally-connected primary windings of said transformer
means being arranged to shift the six-phase output rvoltage
of each transformer means lby a predetermined phase
angle in opposite directions to provide a twelve-phase out
leads, twelve-phase power leads, first and second trans 65 put voltage at said twelve-phase leads and interphase
reaction means connected between said mid-tap leads of
said secondary windings and said unidirectional leads to
leads and said twelve-phase power leads, each of said
former means connected between said three-phase power
permit hal-f of said tubes to operate in parallel at all times.
transformer means including a three-phase primary wind
4. An electric power translation system comprising
ing heXagonally-connected to said three-phase power leads
and three secondary windings each having a mid-tap> lead 70 three-phase power leads, unidirectional current power
and diametrically opposite end connections for providing
leads, twelve-phase power leads, ñrst and second trans
a `six-phase voltage output, a plurality of separate, single
former means connected ’between said three-phase power
phase, asymmetrically-conducting devices ofy a type in
leads and said twelve-phase power leads, each of said
which the rating is determined more by the peakcurrent
transformer means including a three-phase primary wind
than by the average current carried by each of said
ing hexagonally-connected to said three-phase power leads
annalisa
1I
and three secondary windings each having'a mid-tap lead
and diametrically opposite end connections for providing
a six-phase voltage output, a plurality of separate, single
phase, semiconductor rectifying devices of a type in which
the rating isdetermined more by the peak current than
by the average current carried 'by each of said devices,
rtriple diametric connect-ion means for connecting the dia
y12
'phase leads a »voltage 'having symmetrical phases equaly
to »the number-of pairs times twclveandinte'rphase react
ance means connected'in circuit relation withIsaid-'sec
ondary windings to permit apliirality bfsaid devices-to
operate-in parallel at all times.
'it A'r'i electric power *translation system comprising
three-phase power leads, direct-current power leads, poly
metrically opposite end connections of said secondary
phase power leads, a plurality of pairs of transformers
windings of each transformer means to said twelve-phase
lïpower Ileads and for connecting said devices between said
‘unidirectional currentleads and said-twelve-phase power
polyphase power leads, each of the transformers of said
ìleads, said hexagonally-connected primary windings of`
fsaid transformer means being arrangedto shift the six
phase output voltage of each transformer-means by a pre
ldetermined'phase angle in opposite directions to'provide
1a twelve-phase output voltage at said twelve-phase leads
connected between said three-phase power leads and said f
pairs comprising an interconnected delta ythree-phase pri
mary winding connected to said >three-phase -leads and
three secondary windings each having vdiametrically‘op
posite end connections, said primary windings of each
`pair being arranged to produce across the Vassociated sec
ondaryV windingstwo six-phase output voltages each-dis
placed in phase from said three-phase leads’by a predeter
mined angle in opposite directions, means »conductively
‘mid-tap -leads of said secondary windings and said uni
connecting the diametrically opposite end connections of
directional leadsïto permit half of said devices to operate
20 each secondary winding t’o said polyphase leads, a plu
‘in parallel at all times.
rality of mercury `vapor gas tubes each having a single»
"5. An electric ypower translation system comprising
:and interphase »reactance means connected between said
three-phase »power leads, direct-current power leads,
‘polyphase power leads, a plurality-of pairs of transformers
connected between saidl three-phase power leadsfand said
'polyphase power leads, each of the transformers v‘of said
pairs comprising-an’interconnected delta three-phase pri
rnary Áwinding connected to said‘three-phase leads and
phase space currentfpathï-andanode `means and a cathode
means, each of said-tubeshaving its own individual cath- Y
ode means, said devices being `connected=between said
direct-current-»leads and -said plurality ofpairs of trans
formers in an interconnected, delta, six phase, triple dia
metric connection, phase shifting transformers connected
three secondary windings each having diametrically oppo
site end connections, said primary windings of each pair
between said three-phase-power leads yand atleast 'two
separate, single-phase, asymmetrically-conducting devices
8. An electric power translation'system comprising
three-phase power leads, direct-current power-leads, poly
phase power leads, a pluralityv of pairs of transformers
pairs of said transformers to-shift the outputvoltages of
ïbeing arranged to produce ‘across the'associated secondary ,30 each of said pairspby apredetermined phase angleto
produce across said-polyphase leads a voltage having
`windings two six-phase 'output voltages each displaced-in
symmetrical phases equal to the-numberof'pairsitimes
phase from said >three-phase leads by la predetermined
twelve and interphase reactance means connected-incir
' angle in opposite directions, means conductively connect
cuit relation with said vsecondary -wi'ndings to Apermit a
ing the diametrically Vopposite end connections of each
plurality of said devices to operate in parallel at all `times.
secondary winding to said polyphase leads, a plurality of
Kof la type in which the rating is determined more by the
peak current than by-the'average current carried ïby each
connected between said three-phase power leads Aand> said
ofsaid devices, said devices being connected between said
polyphase
power leads,.each of the'transformers of said
40
Idirect-current leads `and said=v plurality of pairs of 'trans-i
pairs comprising an interconnected- delta, three-phase Vpri
’form-ers in aninterconnected, delta, six-phase, ‘triple dia
mary winding connected to said three-phase leads andl
metric connection,"phase shifting transformers connected
‘between said three-phase power leads’ and at least one pair
three secondary windings each'having »diametrically op- v
posite end connections, said primary windings of each Y
of said transformers to shift the output voltages of vsaid
pair being arranged to produce across the associated sec
pair by a predetermined> phase-angle to produce across L 45 ondary windings two six-phase output voltages` each dis
said polyphase leads a voltage 'having symmetrical phases
‘equal to the number ofl pairs times twelve and linterphase
reactance means connected in circuit relation with said
secondary windings to permit ‘a plurality of said devices
to operate in parallel at all times.
’
~
6. An ‘electric power translation system comprising
three-phase'power leads, direct-current power leads, poly
phase power leads, a'plurality of pairs of transformers con
Y nected between said three-phase power leads and said poly
phase power leads, each'of the transformersl of saidrpairs
comprising an intercon‘nectedV delta three-phase' primary
winding connected to said'three-phase leads and three sec
' ondary windings each having diametrically opposite end
connections, said primary windings of-each pair being ar
placed in phaseA from said _three-phase leads by apre
determined angle in opposite-directions, lmeans-conduc
tively connecting »the diametrically opposite'end connec
tions of each secondary >winding to Vsaid Vpolyphase leads,
a plurality of separate, single-phase,semiconductor recti
fying Vdevices of` a type `iniwhich the rating is determined
morek by the peak current=than by-the average currentr
carried by each of said-devices, said devices- ‘being‘con->>
nected between saidkrdirect-current 4leads and said plurality
of pairs of transformers in’an interconnected, deltafsix
phase, triple, diametric connection, phase _shifting trans-.
formersjconnected between saidV three-phase powerleads
and at least two pai'rsfof saidtransformers to’shiftxthe
output voltages of said pair byv a'predeterminedphasg
‘ j ranged toproduce across the .associated secondary `wind-`
angle to produce across >said polyphase leads avoltage "
ings two six-phase output voltages eachV displaced in phase
from` said three-phase leads by a predetermined phase
having symmetrical phases equal to the number -rof pairs
of transformers times twelve _and interphase` reactance
" angle in opposite directions, means conductively connect
¿means connected in circuit relation with said secondary
ing-'the diametricallyy 'opposite end connections of each
windings to ’permit a plurality of saidy devices-to operate inf` »
' « secondary winding to saidV polyphase leads, a plurality
of vapor-electric devices each having a single-phase space
parallel at all times.;
_
t
. Y
- Y
9,. A polyphase connection for supplying power toa
plurality of parallel connected rectifiers comprisingv a '
current path and anode means and a cathode means, each
’ of said devices having its own individual cathode means, i » polyphase power circuit, a‘plurality of transformers each
said'devices being connected between said »direct-current, having an interconnected delta, three-phase primary wind
leads and‘said plurality of pairs of transformers in an' 70 ing’connected to said polyphase power circuit and-three,
interconnected, delta, six phase, triple diametric connec
tion, phase shifting transformers connected between said
secondary windings cionnectedfin a triple diametric con!
'I nection to provide asix-phase output voltage, said plu-V 1
kthree-phase power'leads. and atleast one pair of'said` rality of transformers >being'_divided into .pairswith the "
e transformers toi shift the output vvoltages of-said pair by.Y 75 interconnected delta primaryi-windings'hfleach,pair ar
Y >a 'predetermined‘phase angle to produce across said'p'olyf
ranged to shift the output voltage of'eachtransformer'inï’` t ,
13
3,026,466
said pair with respect to the voltage of said polyphase cir
cuit by a predetermined phase angle in opposite direc
tions to provide a twelve-phase output voltage from each
of said pairs, phase shifting transformer means `connected
between at least two of the pairs of said plurality of trans
formers and said polyphase circuit to shift the twelve
phase output voltage of each of the associated pairs by
a predetermined phase angle to provide a total output volt
age having phases equal to the number of pairs of said
transformers in said plurality times twelve, the required
phase angle shift of said phase shifting transformer means
`being reduced by the phase shift introduced by said inter
connected delta primary windings of said transformers
14
shift the phase of the output voltage of the associated
pair of transformers and to increase the number of sym
metrical phase voltages applied to said group of devices,
the hexagonally connected primary windings of each pair
of said transformers being arranged to introduce predeter
mined phase shifts in opposite directions in the output volt
ages of the different transformers of each of said pairs to
thereby reduce the required phase shift in the associated
phase shifting transformer means and interphase react
ance means connected in circuit relation with said second
ary windings to permit a plurality of said devices to op
erate in parallel at all times.
12. A transformer adapted for connection between
and interphase reactance means connected in circuit rela
three-phase alternating current power leads and a plurality
tion with said secondary windings to permit a plurality 15 of asymmetrically-conducting devices of a type in which
of said rectiñers to operate in parallel at all times.the rating is determined ymore by the peak current than
10. A polyphase connection’for supplying power to a
by the average current carried by each of said devices com
nu
plurality of parallel connected rectiiiers comprising a
prising a three-phase hexagonally connected primary wind
three-phase power circuit, a plurality of pairs of trans
ing connected to said three-phase power leads, and three
formers each having a hexagonally delta connected pri 20 secondary windings each having a mid-tap lead and dia
mary winding connected to said three-phase power circuit
metrically opposite end connections for providing a siX
and three secondary windings connected in a triple diamet
phase output, said diametrically opposite end connections
ric connection to said -rectifìers to provide a six-phase
of said secondary windings being adapted for connection
output voltage, the hexagonally delta connected wind
to
said plurality of asymmetrically-conducting devices, said
ings of each pair arranged to rotate the output voltage 25 hexagonally connected primary winding being arranged
of each transformer by a phase angle of substantially 15°
to shift the six-phase output of said transformer by a pre
with respect to said three-phase power circuit in opposite
determined phase angle.
‘
directions to produce a twelve-phase output voltage from
13. A transformer adapted for connection between
each pair, a plurality of phase shifting transformers con
three-phase alternating current power leads and a plurality
nected between at least one of said pairs to shift the twelve
of semiconductor rectifying devices of a type in which the
phase output voltage of each of the associated pairs by
rating is determined more by the peak current than by
a predetermined phase angle to produce a total output volt
age having symmetrical phases equal to the number of
the average current carried by each of said devices com
prising a three-phase hexagonally connected primary wind
said pairs times twelve, the necessary phase angle shift
ing connected to said three-phase power leads, and three
of each of said phase shifting transformers being reduced 35 secondary windings each having a mid-tap lead and dia
by the predetermined phase rotation introduced by said
metrically opposite end connections for providing a siX
hexagonally delta connected primary windings and inter
phase output, said diametrically opposite end connections
phase reactance means connected in circuit relation with
of said secondary windings being adapted for connection
said secondary windings to permit a plurality of Vsaid
to said plurality of semiconductor rectifying devices, said
rectiíiers to operate in parallel at all times.
40 hexagonally connected primary winding being arranged to
l1. An electric power translation system comprising
shift the six-phase output of said transformer by a phase
three-phase power leads, direct-current power leads, a
angle of substantially 15 °.
plurality of groups of asymmetrically-conducting devices,
a plurality of pairs of transformers each having a hexag
References Cited ín the ñle of this patent
onally connected three-phase primary winding connected
UNITED STATES PATENTS
to said three-phase power leads and three secondary Wind
ings associated with said primary winding and connected
2,039,034
Rose et al. ___________ __ Apr. 2,8, 1936
to said- direct current power leads and to a group of said
devices to apply a six-phase output voltage thereto, phase
shifting transformer means connected between said three
phase power leads and each pair of said transformers to 50
2,166,900
2,193,585
2,602,152
2,714,700
Bohn et al. ___________ __ July 18,
Evans _______________ .__ Mar. 12,
Storsand _____________ __ July 1,
Johnson _____________ __ Aug. 2,
1939
1940
1952
1955
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