Improvements relating to the Distribution of Electrical Energy by Means of Polyphase Currents, and to Induction Coils or Trans- formers therefor.
Year: 1897

page_text: Date of Application, 23rd Aug., 1897
Complete Specification Left, 20th May, 1898-Accepted, 23rd Aug., 1898
[Communicated from abroad by PROF. GUIDO GRASSI, Royal School of Engineers,
Naples, and DOMENICO CIVITA, Engineer Royal Naval Arsenal, of St.
Bartolomeo, Spezia, both in the Kingdom of Italy.]
Improvements relating to the Distribution of Electrical Energy by
Means of Polyphase Currents, and to Induction Coils or Trans-
formers therefor.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:-
In plant for the transmission and distribution of electrical energy it is
frequently impossible to ascertain beforehand how much energy will be required
for illumination, and how much is to be used at the same time for the distribu-
tion of power or any other
purpose. Hence there arise considerable
difficulties where alternating currents are employed. Monophase cur-
rents are not SO well suited to the working of electrical motors
as polyphase currents, and motors constructed on the principle of a rotating
magnetic field offer material advantages over motors operating by 'means of
monophase alternating currents. Where, however, in addition to motors,―
lamps or other apparatus, having no self-induction, are to be operated, the
result, arising from the fact that the last-mentioned apparatus only receives
current from two wires of the polyphase system, is, that the equilibrium of the
distributing system is destroyed, the moment the charge sustained by the several
conductors becomes unequal; and, both complicated and expensive apparatus
or arrangements have to be resorted to, in order so to regulate the system, as
to keep up uniform voltages (or differences of potential), whilst the different
branch-lines are unequally charged.
Now this invention relates to an arrangement which enables polyphase current
to be made use of in such a manner, that the advantages of polyphase systems
are secured in working motors, and the advantages of monophase systems, in
feeding lamps or other apparatus. This object is attained by means of a special
induction coil or transformer, fed by all the currents of the polyphase system
and inducing monophase current of sufficient voltage in a secondary coil or
winding.
The triphase current in this apparatus actuates a laminated iron core having
three arms, each of which carries a primary coil receiving one of the three
primary currents. The three arms which for convenience are designated by
the letters A, B, C, are so connected as to form a closed magnetic circuit for
all magnetic fluxes.
The direction in which the currents are sent through the three coils, respec-
tively, is such, that the magnetic fluxes of two of them.-A and C. for

page_text: example, combine into a magnetic flux of an intermediate phase, while having
at the same time a tendency to generate a magnetic flux in the third arm, the
phase of which corresponds to that of the magnetic flux set up through the wind-
ing of the very arm, B, that receives the third current. Now as the three currents
are placed at 120° to each other, the current which is sent through the coil B
will be reversed, or the coil itself will have to be wound in the opposite direction,
relating to the other two coils.
Or, if desired, the current II may be sent into the coil B without being in-
verted, as in ordinary triphase transformers; but this would reduce the output
of the apparatus.
In one arrangement where the current II is supposed to be reversed, the
coil B, through which such reversed current is sent, should consist of a larger
number of turns than (say, one-and-a-half times or twice as many as) the two
other coils, where it is desired that the primary circuits should not contain an
unduly great number of windings, given the ratio of transmission and the
output of the apparatus; and that, where the coils work idle, i.e. where the
secondary circuit remains open, the consumption of current should be incon-
siderable.
The secondary coils may be wound upon the arm B, when a monophase
alternating current will be set up in such coil. Such secondary winding
terminates at points hereinafter referred to as 3 and 4. Or the secondary coils
may be wound upon the arms A and C only, the currents generated therein being
utilised in a series connection.
In order that, in this case, however, both the output and efficiency of the
apparatus may continue to attain a high degree, the junction of the two currents
must involve the reversion of one of the secondary coils, the two secondary
coils A and C terminating at the points hereinafter referred to as 1 and 2;
and to attain a higher potential, the two secondary windings on the arms A
and C and the secondary winding on the arm B may be connected in series, in
which case the points 2 and 3 are connected together, while the free ends or
points 1 and 4 form the poles of the secondary circuit. Or-as will be readily
understood the points 2 and 4 may be connected, if preferred; when the
points 1 and 3 will form the poles of the secondary circuit.
The primary circuits may be connected together after either of two methods,
known, respectively, as star-grouping" and " mesh-grouping."
66
The primary coils may also receive the triphase current in the manner herein-
after described. Upon the arms B there are wound two primary coils, connected
in series, both with each other and with the primary coils of the arms A and C.
The triphase current is supplied through three conductors I, II and III which
join the ends of the windings of the coils A and C and the point of connection
of the two central coils; the coils upon the three arms A, B, C, being wound
in the manner above described.
The desired voltage of the secondary current will be obtained as a result of the
relation between the numbers of turns of the secondary and primary coils,
respectively.
The secondary current, which is thus generated, is supplied for consumption
to those points, where there are in operation devices best worked by means of
a monophase alternating current. An alternation in the change of the circuit
does not disturb the equilibrium of the polyphase system; or in other words,
the relation between the differences of potential of the several lines remains
practically unaltered, so that the operation of the system is regulated auto-
matically, without necessitating the employment of any additional arrangement
or apparatus of a complicated nature.
This transformer may be carried out in widely varying forms, the number
of turns in the coils, and the shape and number of the wires, or the laminae of
the iron core, being variable according to circumstances, thus the coils, instead
of being wound with copper wire, may consist of copper tubes, strips or the like.

page_text: The transformer is employed in the following manner: then conductors of
the system of transmission and distribution simultaneously supply the n primary
coils of the ordinary polyphase transformers, and the new induction apparatus,
with current, the secondary polyphase currents of the former serve to operate
the rotating current motors, while the secondary monophase current serves for
purposes of illumination and, generally, for feeding apparatus requiring mono-
phase alternating current for their operation.
The novel transformer will also prove serviceable for measuring purposes
in the case of polyphase systems, inasmuch as it enables the measurements to be
carried out by means of the monophase current of the secondary circuit, instead
of by the various currents which do not keep time with the volts. The im-
proved apparatus may be fitted, at will, at any point of the system of distribu-
tion, for the purpose of measuring the voltage or amount of current or ascer-
taining the consumption of energy.
Dated this 22nd day of Au 100%
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
Improvements relating to the Distribution of Electrical Energy by
Means of Polyphase Currents, and to Induction Coils or Trans-
formers therefor.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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 -
In plant for the transmission and distribution of electrical energy it is
frequently impossible to ascertain before hand how much energy will be required
for illumination, and how much is to be used at the same time for the distribu-
tion of power or any other purpose. Hence there arise considerable
difficulties where alternating currents are employed.
Monophase currents are not so well suited to the working of electrical motors
as polyphase currents, and motors constructed on the principle of a rotating
magnetic field offer material advantages over motors operating by means of
monophase alternating currents. Where, however, in addition to motors,-
lamps or other apparatus, having no self-induction, are to be operated, the
result, arising from the fact that the last-mentioned apparatus only receives
current from two wires of the polyphase system,-is, that the equilibrium of the
distributing system is destroyed, the moment the charge sustained by the several
conductors becomes unequal: and, both, complicated and expensive apparatus
or arrangements have to be resorted to, in order so to regulate the system, as
to keep up uniform voltages (or differences of potential), whilst the different
branch-lines are unequally charged.
Now this invention relates to an arrangement which enables polyphase currents
to be made use of in such a manner, that the advantages of polyphase systems
are secured in working motors, and the advantages of monophase systems, in
feeding lamps or other apparatus. This object is attained by means of a special
induction coil or transformer, fed by all the currents of the polyphase system

page_text: and induces monophase currents of sufficient voltage in a secondary coil or
winding.
The principle and construction of the improved apparatus will be best understood
by reference to the accompanying drawings, in which
Figure 1 represents the same in the special form applicable to triphase current,
and
Figure 2 shows a modification of the same.
The triphase current in this apparatus actuates a laminated iron core having
three arms, each of which carries a primary coil receiving one of the three
primary currents. The three arms A, B, C, are so connected as to form a closed
magnetic circuit for all magnetic fluxes.
The direction in which the currents are sent through the three coils, respec-
tively, is such, that the magnetic fluxes of two of them,-A and C, for
example, combine into a magnetic flux of an intermediate phase, while having
at the same time a tendency to generate a magnetic flux in the third arm, the
phase of which corresponds to that of the magnetic flux set up through the wind-
ing of the same arm, B, that receives the third current. Now as the three currents
are placed at 120° to each other, the current which is sent through the coil B
will be reversed, or the coil itself will have to be wound in the opposite direction,
relatively to the other two coils, as illustrated in Figure 1.
Or, if desired, the current II may be sent into the coil B without being in-
verted, as in ordinary triphase transformers; but this would reduce the output
of the apparatus.
In the arrangement shown in Figure 1, where the current II is supposed to be
reversed, the coil B, through which such reversed current is sent, should consist
of a larger number of turns than (say, one-and-a-half times or twice as many
as) the two other coils, where it is desired that the primary circuit should not
contain an unduly great number of windings, given the ratio of transmission
and the output of the apparatus; and that, where the coils work idle,-.e. where
the secondary circuit remains open, the consumption of current should be
inconsiderable.
The secondary coils may be wound upon the arm B, when a monophase
alternating current will be set up in such coil. Such secondary winding is
indicated in Figure 1 by a dotted line terminating at the points 3 and 4. Or
the secondary coils may be wound upon the arms A and C only, the currents
generated therein being utilised in a series connection.
In order that, in this case, however, both the output and efficiency of the
apparatus may continue to attain a high degree, the junction of the two currents
must involve the reversion of one of the secondary coils, as illustrated in Figure 1,
where the two secondary coils A and C are drawn in dotted lines terminating
at the points 1 and 2; and to attain a higher potential, the two secondary wind-
ings on the arms A and C and the secondary winding on the arm B may be
connected in series, in which case the points 2 and 3 are connected together,
while the free ends 1 and 4 form the poles of the secondary circuit. Or as will
be readily understood-the points 2 and 4 may be connected, if preferred;
when the points 1 and 3 will form the poles of the secondary circuit.
«
"
The primary circuits may be connected together after either of two methods,
known, respectively, as star-grouping and mesh-grouping."
The primary coils may also receive the triphase current in the manner illus-
trated in Figure 2. Upon the arms B there are wound two primary coils, con-
nected in series, both with each other and with the primary coils of the arms A
and C.
The triphase current is supplied through three conductors I, II and III which
join the ends of the windings of the coils A and C and the point of connection
of the two central coils; the coils upon the three arms A, B, C, being wound
in the manner illustrated in Figure 1.
The desired voltage of the secondary current will be obtained as a result of

page_text: the relation between the numbers of turns of the secondary and primary coils,
respectively.
The secondary current, which is thus generated, is supplied for consumption
to those points, where there are in operation devices best worked by means of
a monophase alternating current. An alteration in the charge of the circuit
does not distort the equilibrium of the polyphase system; or in other words,
the relation between the differences of potential of the several lines remains
practically unaltered, so that the operation of the system is regulated auto-
matically, without necessitating the employment of any additional arrangements
or apparatus of a complicated nature.
This transformer may be carried out in widely varying forms, the number
of turns in the coils, and the shape and number of the wires, or the laminae of
the iron core, being variable according to circumstances. Thus the coils,
instead of being wound with copper wire, may consist of copper tubes, strips or
the like.
In the case of a polyphase system conveying more than 3 primary currents
say n for instance the core is provided with n arms A, B, C, forming a closed
magnetic circuit. Each of such arms is fitted with a primary winding fed by
one of the n primary currents. One or more or even all of the said n arms are
also fitted with secondary windings which are connected in series with each
other, if their number exceeds one.
The transformer is employed in the following manner; the n conductors of
the system of transmission and distribution simultaneously supply the n primary
coils of the ordinary polyphase transformers, and the new induction apparatus
with current. The secondary polyphase currents of the former serve to operate
the rotating current motors, while the secondary monophase current serves for
purposes of illumination and, generally, for feeding apparatus requiring mono-
phase alternating current for their operation.
The novel transformer will also prove serviceable for measuring purposes in
the case of polyphase systems, inasmuch as it enables the measurements to be
carried out by means of the monophase current of the secondary circuit, instead
of by the various currents which do not keep time with the volts. The improved
apparatus may be fitted, at will, at any point of the system of distribution, for
the purpose of measuring the voltage or amount of current, or ascertaining the
consumption of energy.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, as communicated
to me by my foreign correspondents, we declare that what we claim is:
1. An induction apparatus or transformer, the object of which is to utilize
the two or more currents of a polyphase current system in generating a single
secondary alternate current, and which, in the case of a triphase system, con-
sists of three lamellated iron cores (A B C), so connected as to form a system
of closed magnetic circuits, each of which carries a primary coil (I, II, III),
which coils are supplied with triphase current in the manner illustrated in
Figures 1 and 2 (the direction of the current being reversed in the coil II, if
required, in which case the number of convolutions in the coil B is to be corres-
pondingly increased), and one, two, or all of the cores A B C being provided
with secondary coils, supplying a monophase alternating current, which is
derived from one, two, or all of the secondary coils, connected in series, in order
to enable the total energy obtainable from the three primary circuits to be made
use of in such a manner that, notwithstanding any variations in the charge
sustained by the secondary circuit, the equilibrium of voltage between the three
primary lines may not be disturbed.
2. In a biphase current system, apparatus similar to that referred to in the
1st Claim, from which it differs only in the employment of two primary coils,
instead of three.

page_text: 3. The employment of an induction apparatus or transformer such as is
characterized in the 1st and 2nd claims, adapted to convert a polyphase alternat-
ing current into a monophase one, for the purpose of distributing electrical
energy; such distribution being ensured; in the case of polyphase systems,
by connecting the three, four, or n conductors of such a system with the primary
coils of the transformer; so as to feed lamps or other apparatus with monophase
current from the secondary coil, while polyphase motors receive current direct
from the polyphase conductors, or from the secondary 'windings of ordinary
polyphase transformers.
4. The employment of an induction apparatus or transformer, such as is
characterized in the first and second claims, adapted to convert a polyphase
current into a single alternate current, with a view to the direct and simultaneous
measurement of both the currents and the energy supplied by a polyphase system;
to which end the primary coil of the transformer is connected with the polyphase
conductor, while the measurements of the voltage, amount of current, and
energy, are effected with ordinary measuring instruments in the secondary
circuit.
Dated this 20th dore of M 1900
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.