Improvements in the Distribution of Electricity by Alternating Differential Phase Currents.
Year: 1891

page_text: Date of Application, 21st Feb., 1891-Accepted, 4th Apr., 1891
COMPLETE SPECIFICATION.
Improvements in the Distribution of Electricity by Alternating
Differential Phase Currents.
}
We, MICHAEL VON DOLIVO-DOBROWOLSKY, Electrician, and the Company
"ALLGEMEINE ELEKTRICITÄTS-GESELLSCHAFT," both of No. 22, Schiffbauer
Damm, Berlin, Prussia, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
Our invention relates to the transmission of alternating currents whose respective
phases succeed each other, or differential-phase currents, to distant points of con-
sumption, and its object is to utilize the advantages presented by causing a large
number of alternating currents of the said kind to be produced by the generators
and to act in the motors, &c., without being obliged to employ an excessive number
of transmitting mains. For this purpose the primary currents supplied in plurality
by the generator, are first converted by means of transformers into a reduced
number of secondary alternating differential-phase currents (preferably into three,
differing in their phases by 120 degrees or one third of a phasial length), these
secondary currents are thereupon conducted by a corresponding number of mains
to the distant points and there split again by other transformers into a greater
number of tertiary differential-phase currents, which are then caused to operate in
the motors, lamps or other current-consuming apparatuses. The means for
converting many primary currents into a small number of main currents, and those
serving for the conversion of main currents, into a larger number of operating
currents, may be employed independently of each other.
The mains may be arranged in circuit with the coils of the transformers in
ordinary manner, or by means of the system of connections, in which each main
forms a circuit with one of the other mains and one or more of the transformer-
coils, and which we shall call "concatenated circuits" the said system requiring
but as many mains as there are currents to be transmitted; but in this system a
common return wire may be introduced.
In view of equalizing the tension of the primary currents supplied by the
generator we combine regulating apparatuses and volt-meters with the connections
between the generator and the transformer.
In the annexed drawings
Fig. 1 is a diagrammatic view of a circular transformer and conductive mains
constructed and combined according to our invention.
Figs. 2 and 3 represent the inner part of the same transformer with different
connections between the coils thereof and the mains.
Figs. 4 to 7 are views of other transformers and their connections to' the
mains.
Fig. 8 shows a dynamo producing a plurality of currents, in combination with a
transformer for reducing the number thereof to three.
Fig. 9 represents a transformer for converting three currents into a greater
number in combination with motors and lamps.
Figs. 10 and 11 show two dynamos combined in different manners with trans-
foriners and three mains.
The transformer illustrated by Fig. 1, consists in the iron ring y carrying a
plurality of primary or exciting coils d, and the iron star having three arms
provided with the secondary or excited coils a be, the latter being all connected
together at their inner ends e, while their outer ends are individually connected to
the mains A B C. For completing the line-circuits, the mains A B, A C, B C
are shown connected together at their outer ends by the respective systems of

page_text: lamps I, II, III, three concatinated circuits being thus produced, which require
three mains only. Whenever the coils are supplied with alternating currents in
such manner that the phases of these currents follow one after the other in the
successive coils, a circumrotating magnetic field is obtained, which induces in the
secondary coils a bé three currents of a phasial difference of 120 degrees.
In the modified arrangement shown by Fig. 2, the outer end of the coil a is
connected to the main A, and, by the wire A2, to the inner end of coil b, while the
coils are connected in like manner to the respective mains B C, and, by the
wires B C to the respective coils ca, a system of three concatinated circuits being
thus also produced with but three mains. These systems of concatinated circuits
do not, however, in themselves form any part of my present invention.
Fig. 3 represents an arrangement of circuits which is derived from the onc
described first, by the addition of a common return-wire D, connected at e to the
three coils a b c and split at its distant end into three branches severally attached
to the mains A B C. On account of the currents nearly neutralizing each other
in the said wire D, the same may be made of much smaller section than the mains.
This is the kind of circuit which we employ by preference with our system of
current transmission.
Our invention is, however, entirely independent of the form of transformer
employed, and for this reason we have shown in Figs. 4 to 7 four different con-
structions of transformers provided with coils or sets of coils so arranged and
connected as to be serviceable for the purpose of the invention. Thus according
to Fig. three pairs, a' bc, of induction coils are placed on an annular core fi
and connected to the mains A B C, and with each other by the wires A' B¹ C¹.
According to Fig. 5 three coils a²bc² are wound on a disk-shaped or cylindrical
core and connected pairwise to the mains A B C. Fig. 6 represents a trans-
former composed of the straight core gl with primary coils d'and the like core f³
with three sets of coils a³ ³33, the coils of each set being only separated from
each other by the polar extensions of the core, but forming virtually a single coil.
The three sets of coils are connected at one end to the respective mains A B C,
and at the other end by the wires A B C to each other and to the wire D. The
arrangement illustrated by Fig. 7 consists in a plurality of transformers combined
to constitute a single system, the secondary coils being again connected to form
virtually three coils, which are connected to the mains A B C and the wire D,
substantially in the same manner as in the foregoing case.
It will be perceived that by all these arrangements a plurality of primary
currents are converted into three secondary currents circulating in concatinated
circuits so that they may be conducted to distant points by a small number of
mains. For the effect to be obtained it is, however, not only indifferent what
arrangement of transformer is employed, but it is also immaterial whether, in the
conversion of the currents, the tension of the latter is altered, that is to say,
whether the secondary coils are arranged to produce currents whose tension is
equal to that of the primary currents or higher.
By the means alike to those employed for the conversion of a plurality of
currents into three (or any other limited number) it is also possible to convert
the latter again at the point of consumption into a plurality of tertiary currents,
it being for this purpose only necessary to connect to the mains A B C, or to
these mains and wire D, the coils, ac, a¹¹ c¹, or a² 22, &c., of another trans-
former having its core g or g¹ provided with a plurality of coils d or d¹. The
number of tertiary currents thus produced inay of course be different from that of
the primary currents.
In Fig. 8 is shown a transformer T of the kind represented by Fig. 6, in
combination with a multiple-current dynamo E, regulating apparatuses, current
indicators and volt-meters j. The coils of the dynamo are connected to the
primary coils on core g of the transformer by the wires 1 to 6 and the return-
wires, to 6', while the secondary coils on core f³ are connected to the main ABC
substantially in the manner described relatively to Fig. 2. By means of the

page_text: regulators inserted into the wires 1 to 6 and the volt-meters j, the primary
currents flowing through the said wires are regulated to have equal or nearly
equal tension. The return-wires 1' to 6¹ may, however, be united in one wire of
suitable section without prejudice to the independence of the individual currents
and to the interruption, measuring and regulation of each one singly.
Fig. 9 represents a distributing-system comprising the transformer T' connected
to the mains A B C, moreover two electro-motors M M' of different sizes, and two
systems of lamps L, the transformer T being adapted to convert the three
currents flowing through the mains, into six currents. The motor M has six sets
of exciting-coils which are severally connected to all six coils of the
transformer T by means of twelve wires 1. A portion of the currents circulating
in three of the coils d' is, in addition, utilized for driving the motor M', having
three sets of exciting-coils, the latter being connected to six of the aforesaid
twelve wires 1. Besides this, from four of the wires 1, not connected with
motor M¹, are branched off two circuits supplying current to the lamps L.
In case one or some of the circuits of the generator should be overcharged by
an excessive consumption of current unequally divided among the different portions
of the electric distributing system, the tension of the currents in the said
generator-circuits may be maintained at the proper height by means of ordinary
alternating current dynamos connected to the overcharged coils of the generator.
Thus in Fig. 8 are indicated the brushes W1 W of two such dynamos connected
to the circuits to which belong the wires 1 and 2.
If the current consumed is throughout greater than the amount that can be
furnished by one dynamo, two or more such machines may be connected together
parallel in two different manners. Thus Fig. 10 shows are arrangement in which
the corresponding currents of two machines E' E' unite previous to their passing
into the single transformer T, while according to Fig. 11 the parallel connection
is established subsequent to the transformation of the currents by the two trans-
formers T3 T. The latter arrangement is generally preferable because it does
not require the machines to be constructed for equal numbers of phases. The
machines EE represented is Fig. 11, have for instance four and three sets of
coils respectively.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. In a system for the transmission of alternating electric currents of relatively
differing phases by means of several mains, the combination of a dynamo-electric
machine having a plurality of coils or sets of coils in which, independent alter-
nating currents of relatively differing phases are induced; a transformer provided
as many primary coils as there are induction coils or sets of coils in the dynamo,
and with a smaller number of secondary coils; separate connections between the
induction-coils of the dynamo and the primary transformer-coils, and mains
connected to the secondary transformer-coils either in ordinary manner, or so as
to form therewith concatenated circuits, substantially as described.
2. In a system for the transmission of alternating electric currents of relatively
differing phases by means of several mains and for the distribution of the currents,
the combination, with the said mains, of a transformer provided with as many
primary coils as there are circuits formed by the mains, and a larger number of
secondary coils, and distributing circuits connected to the secondary coils, the said
mains being connected to the primary transformer-coils either in ordinary manner,
or so as to form therewith concatenated circuits, substantially as specified.
3. The combination of the two electric systems specified in the first and second
claims in this manner that the mains proceeding from the secondary coils of the
first transformer, i.e. of the one operating on the dynamo-currents, are connected
to the primary coils of the other transformer,. substantially as set forth.

page_text: 4. The combination, with the electric system specified in the first claim, of
regulating-apparatuses and volt-meters connected with the circuits established
between the dynamo and the transformer, substantially as described.
Dated the Seventeenth day of February 1891.
J. H. JOHNSON & Co.,
Agents.

page_text: [Date of Application, 21st Feb., 1891-Accepted, 4th Apr., 1891
COMPLETE SPECIFICATION.
Improvements in the Distribution of Electricity by Alternating
Differential Phase Currents.
We, MICHAEL VON DOLIVO-DOBROWOLSKY, Electrician, and the Company
"ALLGEMEINE ELEKTRICITÄTS-GESELLSCHAFT," both of No. 22, Schiffbauer
Damm, Berlin, Prussia, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
Our invention relates to the transmission of alternating currents whose respective
phases succeed each other, or differential-phase currents, to distant points of con-
sumption, and its object is to utilize the advantages presented by causing a large
number of alternating currents of the said kind to be produced by the generators
and to act in the motors, &c., without being obliged to employ an excessive number
of transmitting mains. For this purpose the primary currents supplied in plurality
by the generator, are first converted by means of transformers into a reduced
number of secondary alternating differential-phase currents (preferably into three,
differing in their phases by 120 degrees or one third of a phasial length), these
secondary currents are thereupon conducted by a corresponding number of mains
to the distant points and there split again by other transformers into a greater
number of tertiary differential-phase currents, which are then caused to operate in
the motors, lamps or other current-consuming apparatuses. The means for
converting many primary currents into a small number of main currents, and those
serving for the conversion of main currents into a larger number of operating
currents, may be employed independently of each other.
The mains may be arranged in circuit with the coils of the transformers in
ordinary manner, or by means of the system of connections in which cach main
forms a circuit with one of the other mains and one or more of the transformer-
coils, and which we shall call " concatenated circuits" the said system requiring
but as many mains as there are currents to be transmitted; but in this system a
common return .wire may be introduced.
In view of equalizing the tension of the primary currents supplied by the
generator we combine regulating apparatuses and volt-meters with the connections
between the generator and the transformer.
In the annexed drawings
Fig. 1 is a diagrammatic view of a circular transformer and conductive mains
constructed and combined according to our invention.
Figs. 2 and 3 represent the inner part of the same transformer with different
connections between the coils thereof and the mains.
Figs. 4 to 7 are views of other transformers and their connections to the
mains.
Fig. 8 shows a dynamo producing a plurality of currents, in combination with a
transformer for reducing the number thereof to three.
Fig. 9 represents a transformer for converting three currents into a greater
number in combination with motors and lamps.
Figs. 10 and 11 show two dynamos combined in different manners with trans-
formers and three mains.
The transformer illustrated by Fig. 1, consists in the iron ring g carrying a
plurality of primary or exciting coils d, and the iron starf having three arms
provided with the secondary or excited coils a bc, the latter being all connected
together at their inner ends e, while their outer ends are individually connected to
the mains A. B C. For completing the line-circuits, the mains A B, AC, BC
are shown connected together at their outer ends by the respective systems of

page_text: lamps I, II, III, three concatinated circuits 'being thus produced, which require
three mains only. Whenever the coils are supplied with alternating currents in
such manner that the phases of these currents follow one after the other in the
successive coils, a circumrotating magnetic field is obtained, which.. induces in the
secondary coils ac three currents of a phasial difference of 120 degrees.
In the modified .arrangement shown by Fig. 2, the outer end of the coil a is
connected to the main, A, and, by the wire. A to the inner end of coil 'b, while the
coils are connected in.like manner to the respective mains B C, and, by the
wires BC to the respective coils ca, a system of three concatinated circuits being
thus also produced with but three mains. These systems of concatinated circuits
do not, however, in themselves form any part of my present invention.
'
Fig. 3 represents an arrangement of circuits which is derived from the one
described first, by the addition of a common return-wire D, connected atte..to the
three coils a band split at its distant end into three branches severally attached
to the mains A B C. On account of the currents nearly neutralizing each other
in the said wire D, the same may be made of much smaller section than the mains.
This is the kind of circuit which we employ by preference with our system of
current transmission.
Our invention is, however, entirely independent of the form of transformer
employed, and for this reason we have shown in Figs. 4 to 7 four different con-
structions of transformers provided with coils or sets of coils so arranged and
connected as to be serviceable for the purpose of the invention. Thus according
to Fig. 4 three pairs, a¹¹e, of induction coils are placed on an annular core f¹
and connected to the mains A B C, and with each other by the wires A'B'C'.
According to Fig. 5 three coils a² 22 are wound on a disk-shaped or cylindrical
core and connected pairwise to the mains A B C. Fig. 6 represents a trans-
former composed of the straight core g¹ with primary coils d' and the like core f³
with three sets of coils a³ ³°³, the coils of each set being only separated from
each other by the polar extensions of the core, but forming virtually a single coil.
The three sets of coils are connected at one end to the respective mains A B C,
and at the other end by the wires A B C to each other and to the wire D. The
arrangement illustrated by Fig. 7 consists in a plurality of transformers combined
to constitute a single system, the secondary coils being again connected to form
virtually three coils, which are connected to the mains A B C and the wire D,
substantially in the same manner as in the foregoing case.
It will be perceived that by all these arrangements a plurality of primary
currents are converted into three secondary currents circulating in concatinated
circuits so that they may be conducted to distant points by a small number of
mains. For the effect to be obtained it is, however, not only indifferent what
arrangement of transformer is employed, but it is also inmaterial whether, in the
conversion of the currents, the tension of the latter is altered, that is to say,
whether the secondary coils are arranged to produce currents whose tension is
equal to that of the primary currents or higher.
By the means alike to those employed for the conversion of a plurality of
currents into three (or any other limited number) it is also possible to. convert
the latter again at the point of consumption into a plurality of tertiary currents,
it being for this purpose only necessary to connect to the mains A B C, or to
these mains and wire D, the coils a bc, a¹ 'c', or a² ² ², &c., of another trans-
former having its core g or g' provided with a plurality of coils d or d. The
number of tertiary currents thus produced may of course be different from that of
the primary currents.
In Fig. 8 is shown a transformer T of the kind represented by Fig. 6, in
combination with a multiple-current dynamo E, regulating apparatuses h, current
indicators and volt-meters. The coils of the dynamo are connected to the
primary coils on core g of the transformer by the wires to G and the return-
wires 1' to 6', while the secondary coils on core are connected to the main A. BC
substantially in the manner described relatively to Fig. 2. By means of the

page_text: regulators inserted into the wires 1 to 6 and the volt-meters j, the primary
currents flowing through the said wires are regulated to have equal or nearly
equal tension. The return-wires 11 to 6¹ may, however, be united in one wire of
suitable section without prejudice to the independence of the individual currents
and to the interruption, measuring and regulation of each one singly.
Fig. 9.represents a distributing-system comprising the transformer T¹ connected
to the mains A B C, moreover two electro-motors M M' of different sizes, and two
systems of lamps I, the transformer T₁ being adapted to convert the three
The motor M has six sets
currents flowing through the mains, into six currents.
of exciting-coils which are severally connected to all six coils d' of the
transformer T¹ by means of twelve wires l. A portion of the currents circulating
in three of the coils is, in addition, utilized for driving the motor M', having
three sets of exciting-coils, the latter being connected to six of the aforesaid
twelve wires l. Besides this, from four of the wires 1, not connected with
motor M', are branched off two circuits supplying current to the lamps L.
In case one or some of the circuits of the generator should be overcharged by
an excessive consumption of current unequally divided among the different portions.
of the electric distributing system, the tension of the currents in the said
generator-circuits may be maintained at the proper height by means of ordinary
alternating current dynamos connected to the overcharged coils of the generator.
Thus in Fig. 8 are indicated the brushes W1 W2 of two such dynamos connected
to the circuits to which belong the wires 1 and 2.
If the current consumed is throughout greater than the amount that can be:
furnished by one dynamo, two or more such machines may be connected together
parallel in two different manners. Thus Fig. 10 shows are arrangement in which
the corresponding currents of two machines E' E' unite previous to their passing.
into the single transformer T2, while according to Fig. 11 the parallel connection
is established subsequent to the transformation of the currents by the two trans-
formers T3 T. The latter arrangement is generally preferable because it does
not require the machines to be constructed for equal numbers of phases. The
machines E E² represented is Fig. 11, have for instance four and three sets of
coils respectively.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
:-
1. In a system for the transmission of alternating electric currents of relatively
differing phases by means of several mains, the combination of a dynamo-electric
machine having a plurality of coils or sets of coils in which independent alter-
nating currents of relatively differing phases are induced a transformer provided
as many primary coils as there are induction coils or sets of coils in the dynamo,.
and with a smaller number of secondary coils; separate connections between the
induction-coils of the dynamo and the primary transformer-coils, and maius
connected to the secondary transformer-coils either in ordinary manner, or so as
to form therewith concatenated circuits, substantially as described.
2. In a system for the transmission of alternating electric currents of relatively
differing phases by means of several mains and for the distribution of the currents,
the combination, with the said mains, of a transformer provided with as many
primary coils as there are circuits formed by the mains, and a larger number of
secondary coils, and distributing circuits connected to the secondary coils, the said
mains being connected to the primary transformer-coils either in ordinary manner,
or so as to form therewith concatenated circuits, substantially as specified.
3. The combination of the two electric systems specified in the first and second
claims in this manner that the mains proceeding from the secondary coils of the
first transformer, i.e. of the one operating on the dynamo-currents, are connected
to the primary coils of the other transformer, substantially as set forth.

page_text: 4. The combination, with the electric system specified in the first claim, of
regulating-apparatuses and volt-meters connected with the circuits established
between the dynamo and the transformer, substantially as described.
Dated the Seventeenth day of February 1891.
J. H. JOHNSON & Co.,
Agents.