Improvements in Systems of Electrical Distribution.
Year: 1898

page_text: Date of Application, 14th June, 1898-Accepted, 1st Oct., 1898
COMPLETE SPECIFICATION.
Improvements in Systems of Electrical Distribution.
We, THE BRITISHI THOMSON-HOUSTON COMPANY LIMITED, of 83, Cannon Street,
in the City of London, Electrical Engineers, do hereby declare the nature of this
invention (which has been communicated to us from abroad by Charles 1.
Steinmetz, residing at Schenectady, County of Schenectady, State of New York,
United States of America, Electrical Engineer), and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:-
The present invention relates to monocyclic systems of distribution, and con-
sists in combining therewith a three-wire system, whereby light and power may
be efficiently and economically supplied from the same generator.
To these ends there is provided a source of single phase electromotive force,
and connected thereto a three wire system of the ordinary type, in which the
electromotive force across the "outside" wires is equal to the sum of the electro-
motive forces between the two "outside" wires and the "neutral" wire. To
this three wire system, or to translating_devices connected thereto, is applied a
source of dephased electromotive force. In the preferred form of the invention,
one terminal of this source of dephased electromotive force is connected to one
side of the wires of the three wire system, as the neutral wire, and from the
other terminal of the source is carried a fourth or supplementary wire to the
distribution system.
Furthermore single phase translating devices are connected to the three wire
system in the ordinary way, and multiphase translating devices are connected
between any two wires of the three wire system (but preferably the two outside
wires) and the supplementary wire.
In the drawings attached to this specification, Fig. 1 is a diagram of a dis-
tribution system embodying the present improvements, and Figs. 2, 3, and 4 are
views of slightly modified forms.
In Fig. 1, G is a generator having an armature coil C, connected to collector
rings R, R, and a second coil C, connected to an intermediate point in the first
coil and to a third collector ring R2. The coil C₁ is displaced 90 degrees in the
field of force relatively to the coil C. E is a shunt wound direct current
exciter regulated by the rheostat R4, and supplying current to the field winding C
of the generator G. Mains 1, 2, 3, are connected, as shown, to the collector
rings. With this arrangement an electromotive force of displaced phase is main-
tained upon main 2, as is now well understood in the art, so that the electromotive
forces between mains 1, 2 and 3 have a displaced phase relation.
The mains 1, 3, extend over the district to be supplied, and the transformers
are connected to them at suitable points to feed lights or other single phase
translating devices. Such a transformer is shown at T. From the secondary
winding extend three wires, 8, 9, 10, which form a three wire single phase
system. Lights L, L. or other single phase translating devices are connected
in wherever required.

page_text: But at points where it is desired to supply current to multiphase translating
devices, are installed two transformers, T and T. The transformer T is similar
to the transformer T already described; the transformer T is supplied from
the coil C of the generator, and its secondary is interconnected with the three
wire system 4, 5, 6, as shown. 4 and 5 are the outside wires of the three wire
system, and 6 is the neutral wire. Single phase translating devices may be
connected between any two of the wires 4, 5, 6. Multiphase translating devices
may be supplied from any two of the wires 4, 5, 6, in conjunction with the fourth
or supplementary wire 7, which is fed by the transformer T with an electro-
motive force displaced from the electromotive force of the three wire system.
For example, there is shown at M a motor of the monocyclic type, whose field
winding is excited by a direct current machine E¹. Its armature coils, which are
arranged in a manner characteristic of the monocyclic system, are connected to
the wires 4, 5, and 7. M is an induction motor, having a closed secondary, and
its primary windings are coupled and connected in the same manner as are those
of the motor M.
In most cases it is best to couple the motors as just described, between the
outside mains of the three wire system and the supplementary main, but when a
lower voltage is desired in the motor circuits, they may be coupled between the
neutral wire and one of the outside mains of the three wire system and the supple-
mentary wire. Motors M² and M³ are so connected, and are similar in character
to motors M and M¹.
The distribution system shown in Fig. 2 is very similar to that just described.
It differs principally in the fact that the neutral main of the three wire system
extends all the way back to the generator, instead of starting from one or more
of the transformers, as in Fig. 1. The generator G and exciter E, represented
in this figure, are the same as those in Fig. 1, with the addition of a fourth
collector ring R, which is connected to a central point in the main coil C of
the generator armature. The mains 1, 2, 3, as shown herein, constitute the
three wire circuit, and the supplementary main is marked 4. The trans-
formers T, T, similar to the corresponding transformers in Fig. 1, are connected
on the primary side to the mains 1, 3, 4, and on the secondary side to 5, 6, 7.
The generator shown in this figure is assumed to have its armature coils so
proportioned that there is substantially 60 degrees difference of phase between
the mains 1, 3, and the main 4, as in the case with the ordinary type of mono-
cyclic generators now in use. In Fig. 1 the transformers are so wound and
connected that they operate to change the voltage without shifting the phase
relations. In Fig. 2, however, the number and arrangement of turns on the
transformer is such that the displacement of phase on the secondary side is
120 degrees and therefore three phase motors, as M, may be run from the
mains 5, 6, 7. Groups of lamps, L, are fed from the mains, 1, 2, 3, either
directly or through the transformers T2, T3, T. At T there is shown a com-
pensator, or single coil transformer, connected to mains 1, 2, 3 and feeding
multiple series groups of lamps.
In Fig. 3 a system is shown differing from the preceding in the means for
maintaining a displaced electromotive force on the supplementary main. The
generator G in this form has a coil C connected to mains 1, 2, through the
collector rings R, R¹. An independent coil C¹, displaced 90 degrees in the field
of force, is connected by the collector rings R, R5 to the circuit 3, 41. Two
transformers, T, T¹, are used, as before, the primary coil of T being connected to
the circuit 1, 2, and the primary coil of T¹ to the circuit 3, 41. The secondary
of the transformer T leads to the outside mains 5, 6, of a three wire system, the
neutral main 7 being joined to the center of the secondary coil. The secondary
winding of the transformer T has one terminal connected to the supplementary
main B, and the other to the neutral main 7. Lamps L may now be run from
the mains 5, 6, 7, and motors M from the circuit 5, 6, 8.
In Fig. 4 the power generator consists of an ordinary single phase alternator C,

page_text: connected to the mains 1, 2. A compensator T, for which of course a suitable
transformer or arrangement of transformers may be substituted, is connected
across the mains 1, 2, and also to mains 4, 5, 6, forming the three wire system.
Lamps, L, are shown, fed from the mains 4, 5, 6, through transformers. M,
M', M², are motors as before, but in this case three phase motors, having two
of their coils connected to the mains 4, 5, and the third coil connected to the
supplementary main 7. The motors will equalize by transfer of energy over
the main 7, and as long as any one of them is running, any other can be started by
the out of phase electromotive force thus created on the fourth or supplementary
main.
It will be seen that with the improved system a great economy of copper is
attained. For example, in it it is only necessary to run two wires to any building
in which lights are required, while by the addition of a single supplementary
wire motors may also be supplied. On the secondary circuits, all the advantages
of the three wire system are secured, as well as the advantages of the multiphase
systems.
We do not claim in the present application the specific generator shown in
Fig. 2, as such generator forms the subject matter of another application of even
date therewith, viz. No. 13274.
Having now particularly described and ascertained the nature of our said
invention (as communicated to us from abroad) and in what manner the same
is to be performed, we declare that what we claim is:-
1. In a system of electrical distribution, and in combination, a generator
having a main coil, and a supplemental coil at an angle thereto connected at
one end to an intermediate point in the main coil, a three wire distribution system
fed from the main coil, and a multiphase translating device fed from both coils.
2. In a system of electrical distribution, a source of current having a main
coil, and a supplementary coil connected to an intermediate point in the main
coil, means for producing an electromotive force of displaced phase in the supple-
mental coil, a three wire single phase distribution system fed from the main
coil, and a multiphase translating device fed from both coils.
3. The combination of a source of single phase currents, a two wire circuit
leading therefrom, a transformer connected to said circuit, a three wire single
phase system fed from the secondary of the transformer, and a fourth or supple-
mentary wire on which a dephased electromotive force is maintained, inter-
connected with the three wire system.
4. The combination of a generator of single-phase currents having a main
coil, an additional coil on said generator so displaced as to be the seat of an out
of phase electromotive force, a two wire circuit leading from said generator to
a transformer, a three wire single phase system fed from the secondary of the
transformer, and a fourth or supplementary wire fed from the main additional
coil, and multiphase translating devices fed from the main additional coil, and
multiphase translating devices fed from the three wire system and from the
fourth wire.
5. The combination of a source of single phase current, a single phase three
wire distribution system fed therefrom, a single supplementary wire, and a source
of dephased electromotive force connected between the three wire system and
the supplementary wire, single phase translating devices and multiphase trans-
lating devices, the single phase translating devices being fed from the three
wire system, and the multiphase translating devices being fed from the three
wire system and from the supplemental wire.
6. The combination with a single phase winding of alternating current genera-
tor, of a transformer which on one side is connected to the said armature winding
and on the other side to a single phase three wire system, and an additional
source of dephased electromotive force connected to the neutral wire of the three

page_text: wire system, and to a fourth or supplemental wire which forms, with two wires
of the three wire system, a multiphase distribution system.
7. The combination with an alternating current three wire system of a source
of dephased electromotive force connected between the neutral wire of said
system and a fourth or supplementary wire, single phase translating devices
connected to the three wire system, and multiphase translating devices connected
to the three wire system and to the supplementary wire, whereby the four said
wires form a complete system suitable for the distribution of light and power.
8. The combination with the main armature winding of a monocyclic generator,
of two rings connected to the terminals of said winding, an additional armature
coil connected at one end to an intermediate point on the said winding and at its
other end to a third ring, a field magnet in inductive relation to said armature,
connections from two of the first mentioned rings to a transformer, a three
wire single phase system fed from the secondary of said transformer, an additional
transformer connected at one end to a wire leading from the third ring and at
the other end to an intermediate point in the primary of the first mentioned
transformer, a connection from one terminal of the secondary of said additional
transformer to the neutral wire of the three wire system and from the other
terminal to a fourth or supplementary wire, single phase translating devices
connected to the three wire system, and multiphase translating devices connected
to the three wire system and to the fourth or supplementary wire.
121
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1000
THE BRITISH THOMSON-HOUSTON CO. LTD.
W. MARTINDALE,
J. H. THOMPSON,
ALFRED CLEMENTS,
}
Directors,
Assistant Secretary.