TIVIDUAAL OLE Improvements in or connected with Dynamo Electric Machines for Use in what is known as the Three Wire System.
Year: 1896

page_text: Date of Application, 8th July, 1896
Complete Specification Left, 3rd Mar., 1897-Accepted, 22nd May, 1897
L SPECI
CIFICATION.
TIVIDUAAL OLE
Improvements in or connected with Dynamo Electric Machines for
Use in what is known as the Three Wire System.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields, in the County of
London, Gentleman, do hereby declare the nature of this invention (which has
been communicated to me from abroad by the "Electricitäts-Actien Gesellschaft,
Formals W. Lahmeyer & Co." of Frankfort-on-the-Main, in the German Empire)
to be as follows:-
multiple
Dynamo machines as hitherto proposed or constructed for feeding a
system of conductors such as is known as the three wire system without resorting
to the employment of tension dividing machines or storage batteries have been
attended with the drawback that they afford no means for regulating or controlling
the various tensions; the consequence being that installations on the multiple
conductor systems fel by such machines, admitted but of very slight differences or
variations in the charges put upon the several branches of the system. This, too,
is the deficiency exhibited by the double field dynamo constructed in accordance
with Kingdon's British Patent No. 24033. The connection of this machine is a
"double-pole" connection, with four pole pieces projecting from the systein or set
of magnets; every two poles situated side by side being of like polarity.
According to Kingdon's specification it is the exciting coils of poles of the same
the
sign that are always connected in series. Now if the influence produced upon
machine by the operation of the armature be taken into account, it will be seen (as
illustrated in Figure 1 of the accompanying drawings) that two opposite poles of
different polarity are thereby weakened, whereas the two remaining opposite poles
have their magnetism intensified. Therefore, with an increasing charge, the
tension in the branch O. I induced by the poles S' and N₁, would rise, while it
would correspondingly fall in the branch O. II, the excitation of the four windings
being maintained constant. If, however, the excitation of two poles connected in
series ("one behind the other ") and being of like polarity, be varied, the tension
of the two branches will at the same time undergo a change in the identical
direction. Thus it will be seen that in this arrangement of Kingdon's the two
tensions are not capable of being regulated independently of each other. But
what does admit of independent tension regulation or controllability, is the
simultaneous variation of the excitation of two opposite poles of different polarity,
since any two such poles will in all cases be influenced by the armature currents in
a like manner. This object is best attained by connecting the coils in question in
series. Thus, in the arrangement shown in Figure 1, S' and N', and also S2 and N³,
would have to be connected in series, but then, owing to the mutual action of the
two branches, or their influence upon each other, the machine would in this case
manifest an aptness to change its polarity, unless complicated measures of precaution
were taken,
Now the object of this invention is so to connect the exciting coils that no
such "depolarisation" is possible, and so as to admit of a ready and partly
automatic regulation of the several branches, or in other words, of the equalization
of their tension. In such an arrangement as this the branches will excite each
other, that is to say, the exciting coils of the poles S' and N' will be joinel on to
the branch O. 11 induced by the poles S and N'; and conversely, the exciting

page_text: coils S2 and N2 will be joined on to the branch O. I induced by the poles St and N
(Figure 1).
A diagram showing the connection of a treble-conductor dynamo of this
type, with four projecting pole pieces, is given in Figure 2. There is no alteration
of polarity by the action and influence of one branch upon the other where this
method of connection is adopted, inasmuch as the two branches can only be
excited simultaneously, neither being capable of yielding any tension without the
other. When the tension of one branch is increased, a corresponding increase
-within certain limits,-will take place in the tension of the other branch, since
one branch excites the other, so that the arrangement does not require so much
regulating. Were the connection carried out in accordance with Kingdon's
specification, while the charge of the machine was being increased, then, even
though both branches were charged to the same extent, the difference between the
two tensions must go on increasing. The tension in one branch would rise whilst
that in the other branch would fall, but owing to the connection in series of the
proper coils and, more especially, owing to the reciprocal excitation of the two
branches, these differences may to a great extent be compensated for, or balanced,
and not until this is done, will the operation of the system under rational conditions
be feasible.
All that has herein been stated in reference to a treble-conductor machine
with four projecting poles and an armature having two poles is applicable to
machines comprising a greater number of poles, provided always that half of the
number of poles employed may be expressed by an even number.
Dated this 8th day of July 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
Improvements in or connected with Dynamo Electric Machines for
Use in what is known as the Three Wire System.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of London
Gentleman, do hereby declare the nature of this invention (which has been
communicated to me from abroad by the "Electricitäts Actien Gesellschaft,
vormals W. Lahmeyer & Co." of Frankfort-on-the-Main in the German Empire)
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
Dynamo machines as hitherto proposed or constructed for feeding a multiple
system of conductors such as is known as the three wire system without resorting
to the employment of tension dividing machines or storage batteries have been
attended by the drawback that they afford no means of regulating or controlling
the various tensions, the consequence being that installations on the multiple
conductor systems fed by such machines, have admitted but of very slight
differences or variations in the charges put upon the several branches of the
system. This, too, is the deficiency exhibited by the twin field dynamo constructed
in accordance with the Specification of Kingdon's Patent No. 2403/93. The
connection of this machine is a "double-pole" connection, with four pole pieces
projecting from the system or set of field magnets; with like poles situated side
by side instead of being set alternately. According to Kingdon's specification it is
the exciting coils of adjacent poles that are always connected in series. Now if
the influence produced upon the machine by the reaction of the armature be
taken into account, it will be seen (as illustrated in Figure 1 of the drawings
accompanying my Provisional Specification) that two opposite poles of different

page_text: polarity are thereby weakened, whereas the two remaining opposite poles have-
their magnetism intensified. Therefore, with an increasing charge, the tension in
the branch O, I induced by the poles S; and N₁. would rise, while it would
correspondingly fall in the branch O, 11, the excitation of the four windings being
maintained constant. If, however, the excitation of two adjacent poles connected
in series be varied, the tension of the two branches will at the same time undergo
a change. Thus it will be seen that in this arrangement of Kingdon's the two.
tensions are not capable of being regulated independently of each other.
what does admit of independent tension regulation or controllability, is the
simultaneous variation of the excitation of two opposite poles of different polarity,
since any two such poles will in all cases be influenced by the armature currents in.
a like manner.
But
This object is best attained by connecting the coils in question in series..
Thus, in the arrangement shewn in Figure 1, S₁ and N₁ and also S, and N,,-
would have to be connected in series, to attain the desired result but then, owing
to the mutual action of the two branches, or their influence upon each other, the-
machine, would in this case, be liable to change its polarity, unless complicated
precautionary measures were taken. The object of this invention is so to connect
the exciting coils that no such depolarisation is possible, and so as to admit of a.
ready and partly automatic regulation of the several branches, or in other words,..
of the equalization of their tension. In such an arrangement as this the branches
will excite each other, that is to say, the effect of the exciting coils of the poles S₁
and N, will be added on to the branch O II induced by the poles S, and N2; and
conversely, the effect of the exciting coils S, and N2 will be added on to the
branch O, I induced by the poles S, and N, (Figure 1). A diagram shewing the
connection of a three-wire dynamo of this type, with four projecting pole pieces, is
given in Figure 2 of the drawings accompanying my Provisional Specification..
There is no alteration of polarity by the action and influence of one branch upon
the other where this method of connection is adopted, inasmuch as the two branches.
can only be excited simultaneously, neither being capable of yielding any tension
without the other. When the tension of one branch is increased, a corresponding
increase, within certain limits,-will take place in the tension of the other branch,
since one branch excites the other, so that the arrangement does not require so
much regulating. Were the connection carried out in accordance with Kingdon's
aforesaid specification, while the charge of the machine was being increased, then,.
even though both branches were charged to the same extent, the difference between
the two tensions must go on increasing the tension in one branch would rise
whilst that in the other branch would fall, but owing to the connection in series of
the proper coils and, more especially, owing to the reciprocal excitation of the two
branches, these differences may to a great extent be compensated for, or balanced,
and only by this is the operation of the system under rational conditions possible..
All that has herein been stated with reference to a three-wire machine with four
projecting poles and an armature being wound for two poles, is applicable to
machines comprising a greater number of poles, provided always, that half of the
number of poles employed may be expressed by an even number.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
clain is :-
In dynamo electrical machines for use in the three-wire system, exciting or field
magnet coils and their connection with the branches of the system arranged
substantially as and for the purpose hereinbefore described.
Dated this 3rd day of March 1897.
JOHNSONS & WILLCOX.
47 Lincoln's Inn Fields, London, W.C.