Year: 1887

page_text: Date of Application, 12th July, 1887.
Specification Accepted, 26th Aug., 1887.
[Communicated from abroad by GEORGE WESTINGHOUSE, Junior, of Pittsburg,
County of Alleghany, State of Pennsylvania, United States of America,
Engineer.]
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool, and 6 Bank Street, Manchester, both in
the County of Lancaster, and 323 High Holborn, in the County of Middlesex, Civil
Engineer, 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 :-
The invention relates especially to the class of circuits and apparatus employed for
utilizing alternating electric currents for electric lighting and similar purposes.
It is customary to supply an alternating current from a generator of suitable
character, and conduct it through one or more pairs of leads or feeders to points near
where it is to be utilized, and there convert it into a similar current of different
potential. This converted current is then delivered upon main conductors and
employed in operating suitable translating devices, such, for instance, as incandescent
electric lights.
The object of this invention is to make it possible to extend the secondary
conductors to greater distances from the converter-stations and thus reduce the
number of such stations and the feeders required, and to do this without increasing
the size of the main-conductors to an undesirable extent. To accomplish this the
converters are grouped and connected in the system in a peculiar manner, as will be
described in connection with the accompanying drawing, in which figure 1 illustrates
the general organization of apparatus in a diagramatic form, and figure 2 illustrates
an extension of the system. Figure 3 illustrates a modification.
Referring to figure 1, M represents a suitable source of alternating or intermittent
electric currents, and it may be either a single generator or a group of the same,

page_text: One pole of the source is connected with the conductor and the other with the
corresponding conductor 1; these two conductors represent merely the respective
poles of the generator.
Two induction coils or electric converters, C³ and C³, have their respective primary
coils p and p' connected in multiple arc with these conductors by leads or supply
conductors d and d². The secondary coils sand of these two converters are
connected in series with each other. The two terminals are then connected by
conductors 1 and 2 respectively with two main conductors a and a² of a three wire
system. The third or neutral conductor a' is connected by a conductor 3 with the
conductor 4 joining the two coils & and s¹. The translating devices c, c, and c¹, c¹, are
connected in circuit between the conductors leading from the mains a, a' and a³ in the
usual manner. When an equal number of lamps are on both sides of the system, no
current passes through the neutral wire a', nor the conductor 3 leading thereto. If
now all the lights upon one side of the system, those, for instance, between the
conductors a and a¹, should be turned off, while all those between the conductors a¹
and a², remained in circuit, then the secondary coils would still supply the current
necessary to operate the latter devices, its operation not being affected to any practical
extent by the removal of the circuit connections of the secondary coil s¹. If instead
of withdrawing all the translating devices c, only a portion were withdrawn, then the
excess of current necessary to operate the devices c¹ will be supplied through the
neutral conductor 3.
It is desirable in extended systems that the currents should be supplied to the
mains a, a¹, a³, at different points along its length, as thereby the potential is more
readily equalized throughout the system. Other converters arranged in pairs C³, 0,
and C, C may therefore be placed at the proper points. These have their primary
coils in this instance, all included in muitiple arc circuit with supply conductors or
leads d³, d, which are derived from the conductors 1, 1. The secondary coils of the
two pairs are connected with the mains a, a¹, and a in the manner described with
reference to the converters C and (). Now as it may be desired to raise or lower the
potential toward either end of the mains without varying that existing at the other,
resistances are placed in the supply conductors or leads d and d³, and by varying the
amount of resistance thus in circuit, the potential at the terminal of the corresponding
primaries may be varied. A convenient form of resistance consists of an induction
coil or converter G having its primary coil g in the conductor d, and the terminals of
the secondary coil connected through an adjustable resistance y. By adjusting the
resistance in the secondary the potential at the terminals of the primary coil may
be varied.
A similar resistance device G¹ is inserted in the lead d³.
An entirely independent system of translating devices c³, c³, may be included in
circuit between conductors a³, a', and as, supplied from converters C and C. These
have their primary coils connected in multiple arc with the conductors / and ¹ in the
manner described with reference to the other converters.
It will be noticed that thus far the system has been described in connection with a
three-wire system but the number of wires may be indefinitely extended without material
change. In Figure 2 there is shown an organization in which four wires a³, a, a²,
and a are employed. These are supplied by three converters C, Co, C₁₁ The
secondaries of these coils are included between the respective wires a, a ; a, a'; a', a³;
being connected in series. The primary coils are connected in multiple arc with the
leads d and d¹. The operating of this organisation is similar to that already
described.
Instead of having two distinct converters C₁ and (the construction shown in
figure 3 may be adopted. In this instance a single primary coil p is placed upon the
core c and connected in circuit with the conductors d and d¹. The secondary coil is
constructed in two sections and s¹. A single continuous conductor constitutes these
two sections, and the middle point 4 is connected by the conductor 3 with the neutral
wire a. The outer terminals are connected by the conductors 1 and 2 with the
lines a and a respectively.

page_text: Having now particularly described and ascertained the nature of the said invention,
and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I declare that what I claim is :-
1. The combination with a three-wire system of translating devices, of electric
converters consisting of stationary bodies of inductive material and stationary,
primary and secondary coils of insulated wire, such converters having their secondary
coils connected in series with each other, their free terminals being respectively
connected with the positive and negative wires of the system, and their remaining
terminals with the neutral wire, and a source of alternating or intermittent currents
of electricity with which the primary coils are connected in multiple arc.
2. The combination of a three-wire system of electrical distribution, two converters
each consisting of a stationary body of inductive material and stationary primary
and secondary conductors applied thereto, such converters having their secondary
coils connected in series with each other, and with the positive and negative
conductors, a connection from the neutral conductor with the terminals of the
secondary coils and means for transmitting alternate or intermittent electric currents
through the primary coils.
3. In a system of electrical distribution, the combination with a source of alternating
or intermittent currents, of supply conductors connected therewith in multiple arc,
and one or more groups of electric converters having their primary coils connected in
multiple are with said supply conductors, and their secondary coils connected in series
with each other, and with the main conductors of the system, a third or neutral
conductor connected with a neutral point in the group or groups of converters and
translating devices connected between the neutral conductor and each supply conductor,
substantially as described.
4. In a system of electrical distribution, the combination with a source of alternating
or intermittent electric currents of two or more groups of electrical converters located
at different points, and supply conductors leading from said source to each of said
groups and connecting the primary coils of the converters in multiple arc with the
source, regulating devices for each of said conductors and a translating system
connected with the secondary coils of the converters, substantially as described.
5. The combination with three conductors, of the translating devices included in
multiple arc between one of the conductors and the other two conductors, a converter
consisting of a stationary mass of soft-iron and stationary primary and secondary coils
applied thereto, electrical connections between the terminals of the secondary coil and
said two conductors respectively, a connection between the remaining conductor, and
an intermediate point in the secondary coil, and a source of alternating or intermittent
electric currents supplying the primary coil of the converters.
WM. P. THOMPSON & Co.,
Agents for the Applicant.