provements in the Arrangement and Connections of the Windings of Dynamo Machines.
Year: 1899

page_text: Date of Application, 16th June, 1899
Complete Specification Left, 6th Dec., 1899-Accepted, 16th July, 1900
IMVUYIDIONAL DIECIFICATION
Improvements in the Arrangement and Connections of the Windings
of Dynamo Machines.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Build-
ings, in the County of London, Consulting Engineer and Chartered Patent Agent,
do hereby declare the nature of this invention (as communicated to me from
abroad by Victor Karmin, of 1 Backerstrasse No. 1 Vienna, Austria, to be as
follows:
-
:
This invention relates to arrangements and modes of connection to be employed
with dynamo machines having at least two separate continuous current windings,
at least one winding being provided with a collector while the second winding
or the other windings are cut open at suitable places to form bar-groups, these
groups or only some of them being connected at suitable points with the uncut
winding or windings having collectors.
In order that these arrangements and connections shall have the desired effect,
it is necessary that all the continuous current windings shall have such con-
nections and numbers of bars that when provided with a collector they will give
the same electromotive force, and that the bar groups obtained by the said
cutting-open and which are to be connected with the uncut winding, shall
bars, if the total number of bars of the cut winding be designated by S
and the number of parallel circuits of the said winding by 2a 'when used as
continuous current winding.
show
א
66
Before describing these connections and arrangements more particularly, it is
necessary to explain the graphie illustrations employed and the mode in which
the cutting-open is to be effected.
In the following explanation will be shown in respect of the most frequently
occurring case, where the entire winding is cut into fia equal phases, how such a
cutting open is to be effected and how the electromotive forces of the separate
bar groups have to be represented.
In every continuous current winding with an optional number of poles and
armature wires (bars or windings) each wire produces a varying electromotive
force which is not generally of the nature of a sinus curve, but corresponds more
to the form of the field. As now the wires (bars or windings) are distributed
uniformly, either singly or in groups (for instance in grooves), over the armature,
each bar will, at a certain time, have a different phase, that is a different
position relatively to the poles. In order now to determine this position in the
simplest manner, it is convenient to imagine a sinus like distribution of the
field in the air space, in order, from the position of a bar relatively to the
sinus field to be able at once to determine its phase, although such a distribution
of the field is not necessary for causing the connections to be presently described
to operate correctly.
As the induced bars are uniformly distributed over the periphery of the
armature it is possible, by dividing the entire periphery of the armature for
instance. into 6 times equal parts (where p represents the number of pole
pairs) to form groups of bars in which no wire has a greater phase shift relatively
to the other wires of the same group, than 60°, and which taken as a whole.
(i.e. the sum of the electromotive forces of all the wires of a group) produce

page_text: electromotive forces which are shifted 600 relatively to the electromotive forces
of the contiguous groups.
By this division therefore there are obtained as many phases as there are
groups each sixth group having however the same electromotive force, so that
the number of phases is always six.
It is possible, with every continuous. current winding having quite generally
speaking a parallel circuits to obtain, by cutting them open in 6a points,
Ga separated groups of bars, so that in each group only wires of the same phase
occur, that is, only wires lying on the armature in the sections 1, 4, 7, 10 &c.,
or in the sections 1 and 4, 2 and 5, &c. or in a single section, if the 6p sections
into which the armature was divided are designated consecutively 1, 2, 3, to 6p.
It is not possible in all cases and with every kind of winding to obtain 6a
perfectly equal groups of bars, because it may occur that the number of armature
bars S is not divisible by Ga.
In this case the division will have to be so made that the groups of bars have
as nearly as possible the same number of bars, which can always be readily done
without detriment to the following connections.
On the accompanying drawing is shewn at Fig. 1 a practical example how a
cutting-open at 6a points is to be effected for the winding of a four-polar
machine with two separate windings, each winding having a series con-
nection (a:
=
1).
The one winding is cut open in six points A¹ A3 A3 a¹ a² 3, while the other
is uncut and provided with a commutator.
The points I II III 1, 2, 3, of the uncut winding are the points of equal
potential with the points of division of the cut winding.
Other examples of the division of the winding with other kinds of winding are
not necessary to be shewn the given example as to how the division is to be
effected with drum wave-winding being sufficient.
As already stated there are obtained by cutting open a winding in 6a points,
Ga group of bars but always with only 6 phases, as a bar groups have the same
phase. It will therefore be possible in the following to speak always of 6 phases
if it be assumed that the equal phases 'be connected in series or in parallel,
or partly in series and partly in parallel and if the term "phase" be always
intended to indicate such a group of equal phases.
Each phase produces an electromotive force which is shifted through 60°
relatively to the contiguous phases, and as furthermore each phase produces the
same amount of pressure, the electromotive forces of the six phases can be
represented by the sides of a regular hexagon, as shewn in Fig. 2, by the sides
of the hexagon inscribed in the circle. The electromotive force of a phase is
. produced by wires, which each produce equal electromotive forces but having
S
Ga
different phases.
In order now to enable a continuous current winding, with two parallel circuits
to be correctly divided into Ga groups of wires, one commences at an optional
point I and follows the winding in one direction, designating the commencement
of the first bar with A¹. After passing over bars, one arrives at the second
8
8
6a
point of cutting I, indicating the end of the last bar passed over by el, while the
ommencement of the second phase to be passed over is designated by a After
passing over a further bars, one arrives at the point of cutting II, and so
on. The further designations are shewn in Figs. 1 and 2.
When 6 phases have been passed over, then assuming a to be greater than 1,
that is, if the winding has more than two parallel circuits one will arrive at the
commencement of a second first phase and so on.
If however the machine has several separate windings to be cut open, the
second third &c. winding must be cut open at the six points of the ame

page_text: as the first
potential
one. If having been thus explained how
such a cutting open of the winding is to be effected for the special.
case where the division into a equal bar groups was assumed, it will be
easy to effect such a division for every other case in which the number of the
required bar groups is not Ga, but a different one; it is only to be again
observed, that the bar groups to be connected with the uncut continuous current
windings must always have accurately, or nearly so, bars, as was the case for
8
6a
all the bar groups in the example under consideration, in order that the halving
point of the continuous current pressure and at the same time the star centre
of the rotary phase current may be attained.
Figs. 3, 4 and 5 shew arrangements which can be carried out with a continuous
current winding divided into Ga bar groups.
Fig. 3 shews an arrangement in which two bar groups whose phases are
shifted 180° relatively to each other, are connected in parallel and the double
phases thus obtained are connected in star connection. By connecting the 3 free
ends of the three double phases with the points of equal potential of the uncut
winding, there is obtained the arrangement shewn at Fig. 3, where point is
the star centre of the rotary phase currents, and the halving point of the con-
tinuous current pressure.
By connection of the point with a slip ring it is possible to produce an
equalising machine or a generator for a three lead system, as point O always
halves the pressure which exists between the two continuous current brushes."
The cut windings can in this case either be of equal strength with or differing
from the uncut windings as the strength of the cut winding depends upon the
amount of the equalizing current to be produced.
If, on the other hand, cach two bar groups whose phases are shifted 180°
relatively to each other be connected in series and the centres of the three double
phases be connected together at the star centre 0, and the other 6 ends at points
of the uncut winding of equal potential, there will be obtained the arrangement
shown at Fig. 4, which possesses in comparison to the preceding, the advantage
of a better equalisation and of a somewhat smaller loss in copper. With both
arrangements, assuming drum winding, equalising currents are absolutely
excluded, no matter how, the distribution of the field in the air space may be.
If it is a question of constructing a machine for simultaneously giving off ·
continuous current and rotary phase currents, the arrangement at Fig. 3 is
best employed in which in such case the points 1, and 3 must be led to three
slip rings from such a machine with such windings and connections rotary phase
currents can be taken between the points 1, 2 and 3, for instance at 190 volts
for working motors, then between the star centre and the points 1, 2 and 3 also
rotary phase currents but of a less pressure, such as 110 volts, for lamps, and
lastly between the continuous current brushes about 300 volts continuous current,
which will be halved by the neutral point 0. If the rotary phase current
pressure should appear to be too small in proportion to the continuous current,
the former can be doubled by arranging the connections as at Fig. 5 where the
same double phases as before are arranged in star connection, and the centres
thereof are connected with points of equal potential of the uncut winding,
Other arrangements of the connections are possible in particular when the
machine has windings with more than two parallel circuits (a > 1) as such a cut
winding has 6 instead of 6 phases, but where a phases are always of perfectly
equal value. It is however not necessary to go farther into this question, but it
suffices to repeat the main feature of all these arrangements, namely that when a
machine is provided with at least two separate windings, all having such con-
nections and number of bars as to give with a collector the same continuous
current-electromotive force, and if at least one winding is provided with a
collector while the others are so cut open that the bar groups produced have Ga
.

page_text: bars, then phases are obtained which have the property that if suitably connected
(for instance as at Figs. 3, 4 and 5) they will always give the star centre or
neutral point O, and that no equalising currents can be produced however the
distribution of the field in the air space may be arranged.
Dated this 16th day of June 1899.
ABEL & IMRAY,
Agents for the Applicant.
Improvements in the Arrangement and Connections of the Windings
of Dynamo Machines.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Build-
ings, in the County of London, Consulting Engineer and Chartered Patent Agent,
do hereby declare the nature of this invention (as communicated to me from
abroad by Victor Karmin, of 1, Backerstrasse, No. 1 Vienna, Austria), and in
what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
This invention relates to arrangements and modes of connection of the wind-
ings to be employed with dynamos, which enable both continuous and alternating
currents to be taken from a dynamo, and, in addition, to divide the continuous
current pressure into two halves.
To be able to halve the pressure of an electric current means, as is well known,
that one can determine a point which at all times lies as regards the pressure
accurately midway between the two poles of the source of the current.
The improved arrangements and modes of connection consist of combinations
of ordinary continuous current windings with alternating current windings, in
which the pressure delivered by the parts of the alternating current winding
must stand in an accurately determined ratio to the pressure developed by the
continuous current winding. In order to readily determine the conditions under
which the electromotive forces are produced in the desired proportion's in the
separate parts of the winding it is preferable to assume the rotary-phase current
winding to have been produced from a continuous current winding. This method
affords the best explanation of the new mode of connection includes all cases that
may occur, and allows of the formulating of a general rule, by which the
practical carrying out of the method can be effected, in a concise manner.
From this point of view any machine can be used for carrying out the new
method which has at least one continuous current winding closed in itself and is
provided with a commutator and a second continuous current winding which
is also closed.in itself but is without a commutator if these two windings have
such a mode of connection and number of bars, that the continuous current
electromotive forces induced therein are equal to each other.
In carrying out the new method of connection, the one closed continuous
current winding remains in connection with its commutator, the second winding
or set of windings is or are divided into corresponding rotary-phase current
winding sections (by cutting the windings open) and the rotary-phase current
winding sections thus obtained are connected with each other and with the
first named continuous current winding (or with the commutator thereof)
according to definite rules.
In dividing the second winding into sections the main point is to obtain six
rotary-phase current winding sections, whose induced electromotive forces are
equal and are shifted in phase through 60° relatively to each other. The induced
alternating current electromotive force of each of these six winding elements
must be equal to one half the alternating current electromotive force which is
produced from the continuous current winding with commutator when 2 points
of this winding, shifted through 180° relatively to each other are connected
with two sliding contact rings.

page_text: In the first part of the following description the formation of the rotary phase
current winding elements will be dealt with, in the second part, the arrangement
and connection of these elements with the uncut continuous current winding
having a commutator, and in the third part the application of the new arrange-
ments will be considered. Before-setting up a general rule as to the method
by which the said 6 winding elements can be obtained by cutting open the
continuous current winding, it is necessary to shortly describe the graphic
illustrations employed.
With every continuous current winding with optional number of poles and
armature bars or coils, each bar or wire produces a varying electromotive force,
which does not follow a sine curve but one corresponding to the form of the
field. As now, the bars or coils are uniformly distributed over the armature,
either singly or in groups, each bar will at a certain moment have a different
position relatively to the poles, i.e. a different phase. In order to determine
this phase in the simplest manner it is convenient to assume a sine-like distribu-
tion of the field in the air space, and in order then to determine the phase of a
bar at once from its position relatively to the sine field, although such a distribu-
tion of the field is not necessary for the correct working of the mode of connection
to be presently described.
The induced bars being thus uniformly distributed over the periphery of the
armature it is possible by dividing the entire periphery of the
armature, for example into 6 times equal parts ( representing the number
of the pole pairs), to form groups of bars in which no bar has a greater phase-
shift than 60° relatively to the other bars of the same group, and which, taken
as a whole (ie. the sum of the electromotive forces of all wires of a group)
produce electromotive forces which are shifted 60° relatively to the electromotive
forces of the contiguous groups. By this division there are consequently obtained
as many phases as groups, each sixth group having however the same phase of
the electromotive force, so that the number of actual phases is always reduced
to 6.
If the continuous current winding were to be cut open in this manner only
considering the number of pole pairs, there would be obtained a greater number
of cuts than is strictly necessary; one would therefore have, in forming the six
winding elements, to do with an unnecessary large number of groups of equal
phase and in addition special care would have to be taken that the connection of
the groups of equal phase to form a winding element were affected in such manner
that the induced electromotive force of such a winding element was equal to one
half the electromotive force of the uncut continuous current winding. In the
following it will be shown that the number of necessary cuttings depends upon
the arrangement of the continuous current winding and not upon the number of
pole pairs; also, a general rule will be set up as to how the cutting open is to
be effected and how the parts cut open have to be connected to form the above
named winding elements."
As is known, there exists in every closed continuous current winding at least
one current branching. Thus in the simplest case of a bi-polar machine with a
closed continuous current winding not all the bars or coils can work in series, but
the two halves of the winding are connected in parallel. If a bi-polar machine
is provided with several continuous current windings closed in themselves, there
will be a current branching in each of these windings. If the machine is multi-
polar, the number of the branch currents only depends upon the description of
winding used. Thus for example with a purely series connection of the bars or
coils of a closed winding only a single current branching occurs, exactly as with
a bi-polar machine. With a purely parallel connection of the bars, as many
current branchings occur as there are pairs of poles. With a mixed series and
parallel connection of the bars or coils on the other hand, the number of current
branchings can be varied at will.
As, in consequence of the existence of every current branching there are
produced two parallel acting winding sections, and as at least one current

page_text: branching must occur, it follows that the number of parallel acting sections of
a continuous current winding can always he expressed by an even number:
It is assumed that the armature winding, which as above stated consists of at
least one closed continuous current winding with commutator and at least one
closed continuous current winding without commutator, has altogether s bars
or coils that the number of all current branchings be ; and the number of
the parallel acting winding sections 2a; it is further assumed that each closed
continuous current winding would if used as such, give equal pressures.
Under these assumptions the following general rule holds good for the cutting
open of the windings without commutator. The winding is cut open at any
desired point and it is followed along the connected bars thereof until bars
(or coils) have been passed over.
8
Gr
Geb
A second cut is now made and in like manner as above bars are passed
over, before a third cut is made and so on. If the number of bars or coils of the
winding is divisible by the last cut must coincide with the first one. If
8
6 %
however the number of bars or coils is not divisible by
compensation must be made.
a corresponding
6.1
By means of these cuttings the winding is divided into a number of sections
d'visible by 6.
The induced electromotive forces of the first six parts obtained by such cutting
are equal to each other in extent, or (if compensation had to be resorted to)
practically equal, and are shifted through 60°. In addition the electromotive
forces are in extent, equal to half the electromotive force of the uncut winding
which this would give if used as continuous current winding.
In the next following winding sections of the cut winding the electromotive
forces of the first six winding sections are repeated in the same sequence that
is, the electromotive force of the seventh, thirteenth, nineteenth &c. sections, is as
regards extent and phase equal to the electromotive force of the first winding
section the electromotive force of the 8th, 14th, 20th &c. section is equal to that
of the second &c.
As it is essential (as will be presently shown) that the winding elements that
are to be formed from the cut winding and connected with the uncut winding
with commutator, shall have half the electromotive force of the continuous
current winding with commutator there will be obtained in the case under
consideration, the six necessary winding elements by the parallel connection of
the sections of equal phase. Thus the 1st, 7th, 13th &c. section of the cut winding,
when connected in parallel will form the first winding element; the 2nd, 8th,
14th, &c. section the second winding element &c.
If the armature of the machine has, in addition to the continuous current
winding with commutator more than one closed winding, each one of these is
cut open and treated in the above described manner.
A winding element then consists of the parallel connected winding sections of
equal phase of all the cut windings.
The above described invention will now be illustrated by means of an example
for which purpose reference will be had to the drawings accompanying my
Provisional Specification.
Fig. 1 shews the developed diagram of the winding of a quadri-polar con-
tinuous current machine (7. 2) with two separate closed windings, the one
winding being provided in the usual manner with a commutator while the other
is divided in the above described manner into 6 winding elements, which are then
connected with each other and with the first winding, or with its commutator.
The total number of the bars s is 84. Both, windings are formed in the same
manner. Consequently each winding has 42 bars. As both windings have purely

page_text: =
===
series connection a is 2 for both. The windings are formed as drum wave
windings, the one wave length y¹ 19, the second y³ 21, that is, in con-
necting the bars in the one case 19 bars have to be passed over and in the other
case 21 bars.
.
•
The consecutive bars of the windings to be cut open are 1, 20, 41, 60, 81,
16, 37, 50. 77, 12; 33, 52, 73, 8, 29, 48, 69, 4, 25, 44, 65, 84, 21, 40, 61, 80,
17, 36, 57, 76, 13, 32, 53, 72, 9, 28, 49, 68, 5, 24, 45, 64, 1.
The consecutive bars of the winding with commutator are 2, 23, .42, 63, 82, 19,
6a 6X2
The first cut is made between the 4th and the 25th bars and the commencement
of the cut winding section is marked A'. For obtaining the next point of cutting,
8
6x2
according to the general rule, therefore connected bars 25, 44, 65, 84, 21,
40, 61, have to be passed over. The next cut has therefore to be made between
the bar 61 and the bar 80.
'
The end of the first section is marked e¹ and the beginning of the next section
is marked a. . The operation is continued in like manner, in marking the end
of the second section E, the beginning of the third section A" the end hereof e³
&c..
The sixth cut coincides with the first one in the example under consideration.
Consequently, the winding sections Ale; 'E; A²²; a²²; A³e; E³ constitute
at the same time the winding elements.
If the cutting of the winding had been such as to form 12, 18, &c., sections
instead of 6, the sections having the same phase would, as above stated have to
be connected to form a single winding element.
Other examples of the division of the winding with windings of a different
kind, such as ring looped winding or ring wave winding, also looped drum
winding, need not be given. It remains to be shewn that under certain circum-
stances the 6 necessary winding elements can also be obtained by cutting open a
continuous current winding the electromotive force of which is smaller or larger
than that of the continuous current winding provided with commutator.
8
If in this cases be taken to designate the number of the bars of the winding
to be cut, a the number of the branch currents thereof 2a the number of parts
thereof working in parallel if the winding were used as a parallel winding, then
by effecting cuts after passing over every consecutive bars, the winding
can be divided into Ga winding sections. The electromotive force of each such
winding section is, in extent equal to half the electromotive force of the continuous
current winding before it was cut open.
6a
Having shewn above how the six winding elements can be obtained by cutting
open the continuous current winding, I will proceed to describe the arrangement
of the connections which have to be effected with these elements and with the
continuous current winding provided with committator for the purpose of this
invention.
"
For brevity's sake the six winding elements will in the following be called
phases." The consecutive phases are designated, corresponding to Fig. 1, by
A'e': 'E'; A²e²; ²²; A³¹³; a³E³.
.
In order to show clearly the arrangement of connections of the six phases and
the continuous current winding with commutator, a mode of representation has
been chosen which renders it possible to read off directly from the diagram
the pressure between two points of the combined rotary phase current winding
and the continuous current winding.
<<
The electromotive forces which exist between any optional points of the con-
tinuous current winding with commutator, and the six phases," can be repre-
sented, as regards their extent and direction according to Fig. 2 in the simplest
possible manner, by indicating the continuous current winding with commutator

page_text: by a closed circle while the six phases are indicated by a circle of the same
diameter cut open at six places.
"
The two circles cover each other at points of equal potential. Thus the six
equidistant sectional points of the one circle, which represent respectively the
commencement and endings E³A¹; c'a¹; E'A²; c²a²; E²A³; c³¹³ of the six
phases" Ale; a¹E¹; A²²; a²E²; A33; E, coincide with the six points I, 1,
II, 2, III, 3, of the continuous current winding with commutator, E A¹ and I;
ela and 1.
being as above stated points of equal potential. With this
mode of representation the electromotive force between two optional points is
given as regards both extent and direction,. directly by the distance between
these points. The distance of the points A¹ and et, that is, the distance A¹¹
thus gives the electromotive force of the phase A'e¹; a¹E gives the electromotive
force of the phase a¹E. The phase shift of the electromotive forces A¹e and a¹E¹
is given by the angle of 60° which the distances Ale¹ and a'E' form with each
other.
The greatest electromotive force which exists between two points of the con-
tinuous current winding with commutator, that is, the pressure which this wind-
ing when used as such, gives, is represented by the diameter of the circle.. The
electromotive force of each phase" is, as to its extent, equal to one half the
electromotive force of the continuous current winding, as the distance A¹e¹ equals
one half the diameter of the circle.
"
In order that the electromotive force which exists between any two points of
the winding may be read off directly from the diagram in the above described
connection of the six "phases" and the continuous current winding with com-
mutator for carrying out the new combined rotary phase current winding and con-
tinuous current winding, the separate phases are shifted parallel from the position
which they occupy in Fig. 2 to the points of connection. Thus, for example,
if the commencement A¹ of the phase Ale¹ is to be connected with the point 3 of
the continuous current winding with commutator, this is made apparent by
shifting parallel to itself the phase A'e which in Fig. 2 covered the part II of
the continuous current winding, in such manner that the point A coincides
with the point 3. This connection is shewn in Fig. 3. It will be evident that.
by the connection of A¹ with 3 the electromotive forces between any point of the
phase Ale and every point of the continuous current winding will be com-
pletely changed but that neither the electromotive forces between two points of
the phase Ale or the electromotive forces between two points of the continuous
current winding will be changed in any way.
The altered electromotive force between any point of the phase A'e' and a point
of the continuous current winding is given directly by the distance between'
these points. The electromotive force between the point A¹ and the point I is
given by the distance A'I (while before the connection of A¹ with 3 it was zero)
the electromotive force between the point e¹ and any point of the continuous
current winding is, as to its extent given by the radius of the circle.
"
The shift of phase" Ale¹ relative to the other "phases". or separate sections
of the continuous current winding has of course not been altered by the connection
of the point A¹ with 3.
With the first mode of construction of the combined rotary phase current wind-
ing and the continuous current winding each two "phases" shifted 180° relatively
to each other are connected to form a "double phase" and the three double
phases thus obtained are connected in star form. Between the free ends of the
double phases there exist therefore three equal electromotive forces shifted 120°.
The three ends of the rotary phase current windings thus obtained are connected
with such points of the continuous current winding between which electro-
motive forces act that are the same as regards extent and direction as those
between the said three ends. This arrangement is shewn in Fig. 3.
That this connection of two opposite "phases" constitutes a parallel connection
thereof will be seen best from the fact that with the parallel shift of the

page_text: phases" into the connecting position and the connection of two end points, the
other two end points cover each other. Thus if for example the ends A¹ and E³
of the "phases" Ael and a²E3 shifted 180° relatively to each other be connected
then the points e¹ and a² cover each other, which shows that no pressure exists
between the points e¹ and a³.
The three double phases A'e¹, Ea³; A²², E³a³; A³, Ela¹, are connected in
star form by connection of the points a¹ a² a³ el e² e in such manner between the
points A1 A3 A3 that there exist three equal pressures A'A2, A2A3, AA1, shifted in
hase through 120° relatively to each other. The outer points A¹ A² A³ or E¹
E3 E3 of the rotary phase current winding connected in star form are connected
with such three points 3, 1, 2 of the continuous current winding between which the
same electromotive forces exist (as regards extent and direction) as between the.
points A1 A2 A³.
Thus between the points 3 and 1 the pressure 3-1 exists which as regards
extent and direction is equal to the pressure A¹A³, while the pressures 1-2
and 2-3 are respectively equal to the pressures A2A3 and A³A!.
It will be readily seen that the three double phases might also be so con-
nected in star form that the points A1 A2 A3 E1 E2 E3 are connected, and that the
three rotary phase current pressures, shifted 120° relatively to each other occur
between the points a¹ a² a³.
The points a a² a³ would however in that case not be connected to the
points 3, 1, 2, but with the points I, II, III, of the continuous current winding
with. commutator.
With the second construction of the combined rotary phase current winding
and continuous current winding each two "phases" that are shifted 180° rela-
tively to each other are connected in series to form a resultant phase," and the
three resultant phases are connected together at their middles.. The six free ends
are connected with such six points of the continuous current winding between
which the same pressures (as to extent and direction) exist as between the
six- end points of the resultant phases.
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This arrangement is shewn at Fig. 4. It will be evident that, for example,
the phases Ae and a,E, are connected in series by connection of the ends A,
with , as with the parallel connection of the "phases at the connecting
position the two ends e, and E, are at a distance apart Ea, which is equal to
double the distance A₁e, or a E.
=
The pressures which exist between the free ends of the "resultant phases"
which are connected by their centres A, A, A₁ or a, a α are represented, as
regards both extent and direction by the distances E, E, E‚Æ‚¤‚_e̟‚Ë„
Ee. The free ends e, E, e₁E₁, E, are connected with the points I, 1, II, 2,
III, 3, of the continuous winding, these points being so chosen that between two
points of the continuous current winding such as I and 1 the same pressure
both as to extent and direction, exists as between the points of the rotary phase
current winding e, and E, connected thereto. It will be evident that the "resul-
tant phases" can also be produced by the connection of the other ends of the
phases. Thus the points e, and E, of the phases A,e,, and a.E, that are shifted.
180° from each other, might be connected; in that case point A, would have to
be connected with 3, and the point a₂ with II.
In a third mode of carrying out the combined rotary phase current and con-
tinuous current winding, each two phases shifted 180° are again connected in
series to form "resultant phases" and the three resultant phases are connected
in star form. The three centres of these resultant phases are then connected with
such three points of the continuous current winding with commutator between
which the same pressure (both as to extent and direction) exist as between the
three centres of the three resultant phases.
This arrangement is shewn at Fig. 5. The three resultant phases" A₁a,
A A, are produced by series connection of the phases A₁e, and a₂E, A₁₁
and aE A and a,E,, and they have their ends a, a, a connected together.

page_text: The point of connection is marked O. Between the middle points e̟, and eg of
this rotary phase current star winding exist the pressures è̟é̟é̟é̟, ее₁ which are
.equal both as to extent and direction-to the pressures 3-1, 1-2, 2-3 between
the points 3, 1, 2. Consequently c, is connected to 3, c, to 1, and eg to 2.1
It will be evident that for instance, for forming the resultant phase
of A, e̟ and ɑE, one might just as well connect the points A, and
and then the point e, with the points a₁ and ; and the point A, with point 3 of
the continuous current winding.
out
together,
Finally also, the three resultant phases A, A Ag, could be connected with
the ends A, A Ag in star form; the centres e, and would in that case
have to be connected with the points II III and I of the continuous current
winding, as the pressure e e̟ would be equal to the pressure ȚI III, the pressure e
III, 1, and I II.
==
It is an essential feature of the combined rotary phase current and continuous
current windings represented at Figs. 3, 4 and 5 that between two points of the
rotary phase current winding there always exists the same pressure both as
regards extent and direction, as between those two points of the continuous
current winding with which the said two points are connected.
In consequence hereof there is always obtained a combined rotary phase current
and continuous current winding which consists of several windings closed in
themselves, yet connected with each other.
0
In each of these closed windings the sum of the electromotive forces is
Thus the combined winding according to Fig. 3 may be considered as consisting
of the closed windings 31 E A 12 EA, 23 E, A
In the circuit 31 E, A, the electromotive force of the part-31 is equal to
the resultant electromotive force of the parts A₁e, and a,E,, consequently the
sum of the electromotive forces =0.
In the same way the sum of the electromotive forces in the closed winding Il
EA in Fig. 4 is = 0.
As the sum of the electromotive forces of each of the closed windings of which
the combined rotary phase current and. continuous current winding is composed
is == o, there can also occur. no inner currents in the combined construction
by which a useless expenditure of electrical energy would be occasioned.
The winding can therefore only yield current when separate points thereof
are connected through outer resistances. The entire current produced by the
winding then passes into the external resistance.
The improved construction is especially suited for generators and allows of the
simultaneously delivery of rotary phase current and continuous current.
'
A further very important advantage of the arrangement is that in consequence
of the peculiar mode of winding, a certain point of the winding, namely the
star centre 0, in which the rotary phase current winding elements are connected
with each other, is always situated between the two poles of the continuous
current winding, as regards pressure, whereby it is rendered possible to feed a
three-wire system without the use of a special equalising device as an equalisa-
tion is effected in the simplest possible way in the winding itself.
The continuous current is taken off from the commutator of the uncut con-
tinuous current winding by means of brushes in the usual manner. For taking
off the rotary phase current the three outer ends of the rotary phase winding
must be connected to sliding contact rings, to which rings the three. outer leads
are then connected by means of contact springs or brushes. If the machine is to
supply a three-wire system the two outer conductors are connected to the brushes
on the commutator and the middle conductor is connected by means of sliding
contact rings and springs with that point of the winding which always halves
the continuous current pressure, that is, with the star centre 0.
According as to whether the one or the other property of the new construc-
tion is to be more particularly utilised the one or other of the three arrangements
shewn at Figs. 3, 4 and 5 can be employed.

page_text: If in the construction at Fig. 3 the outer conductors of a three-wire distributing
system be connected with the commutator brushes, and the middle conductor with
the point and in addition three other conductors be connected to the points 1,
2, 3, that is, the connecting points between the rotary phase current and con-
tinuous current windings, there will be obtained: between the outer conductors of
the distributing network a continuous current of the full pressure of the closed
continuous current winding (this pressure is represented by the diameter of the
circle) between each outer conductor and the middle conductor connected to
the point 0, the half of the continuous current pressure (this pressure is repre-
sented by the radius of the circle); between each two of the three conductors
connected to the points 1, 2, 3, alternating currents whose pressures are given,
both as to extent and direction, by the distances A,A₂, AA, AA₁, and as shewn,
are shifted 120° relatively to each other as to phase: lastly, between the three
conductors connected to the points 1, 2, 3, and the conductor connected to the
point 0, alternating currents whose pressures are given, both as to extent and
direction, by the distances OA,, OA, OA,, and which are shifted as to phase
120° relatively to each other.
It should be stated that the "maximum" alternating current pressure is
always meant here, and not the "effective essure.
"
"
If, for instance, the entire continuous- current pressure were 300 volts, and
consequently the pressure between middle conductor and the outer conductors
150 volts, the effective" greater alternating current pressure would be about
190 volts and the effective smaller alternating current pressure about 110 volts.
When using the invention for a three-wire system with unequal loads on the
two parts the mode of effecting an equalisation can be best demonstrated by con-
sidering the closed continuous current winding and the three closed windings 31
"
A 12 E₁₁ A₂, 23 E, A, as windings independent of each other.
The continuous current winding can be considered as permanently connected
between the two outer conductors of the three-wire system, yielding a current
of the full pressure. The three other windings cach composed of parts of the
continuous current winding and of two phases" yield a current of one half the ⚫
pressure of the continuous current winding, and are connected between the middle
conductor of the system and one of the outer conductors, each winding being
connected alternately with the two outer conductors and permanently with the
middle conductor. The current supplied by the continuous current winding flows
from the one brush to the one outer conductor, flows through the resistances
(lamps, motors &c.) situated between this and the middle conductor and the outer
conductor, and passes back from the latter to the second brush. If only the
continuous current winding were in existence, then in the case of unequal
loads on the two parts of the system, that is, when the resistances between the
one outer conductor and the middle conductor were not equal to those between the
latter and the other outer conductor, no equalisation could be effected without
special equalizing apparatus or batteries. With the new arrangement however,
there are continuously interpolated between the middle conductor and each of the
outer conductors windings 31 EA, &c. which continuously produce an
electromotive force equal to one half that of the continuous current winding and
which supply more or less current in proportion to the consumption in the
particular part of the system, so that the pressures between the middle conductor
and the two outer conductors remain equal. This representation of the equalizing
action is not intended as a perfectly correct explanation of the phenomena that
take place, but only as an approximately correct representation thereof. If the
machine is intended solely to supply a three-wire system, it is advisable to use
the construction represented at Fig. 4, as this insures a more uniform action and
a better utilisation of the conducting material used for the windings.
The two outer conductors of the three-wire system are as before connected to
the commutator brushes and the middle conductor with the point 0. Of course
rotary phase current could also be taken from this construction.
If both rotary

page_text: phase and continuous current are to be taken off, but the former is to receive a
greater pressure than would be possible with the arrangements at Figs. 3 and 4,
the arrangement at Fig. 5 may be used with advantage.
The outer conductors are as before connected to the commutator brushes, while
the middle conductor of the three wire system is connected with the point O.
The three points A, A, A, are connected with sliding contact rings which in
their turn are connected with the three conductors of the three wire system by
means of suitable contact devices. Between each two conductors of this system
exist the alternating current pressures A,A2, AA, AA₁ shifted 120° relatively
to each other.
If it were desired, in addition to have a rotary phase current of less pressure,
the conductor connected to the star centre O might be utilised, and the pres-
sures A,0, A,0 and A0, be taken off.
It will be evident that the several properties of the above described arrange-
ments may be utilised either separately or in any desired combination: thus for
instance, rotary phase and continuous current might be taken off, but the con-
tinuous current pressure not be divided, or only continuous current might be
taken and the pressure thereof be divided as described, or again two kinds of
rotary phase current and continuous current may be taken and the latter be
divided in two.
66
If it be only desired to divide the continuous current pressure and no rotary
phase current be taken, less than six phases can be used, as, in principle a single
phase" suitably connected to the continuous current winding would be suffi-
cient although from practical considerations such an arrangement could not be
recommended.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare, that what
I claim is
In continuous current machines having at least two separate continuous current
windings and with such connections and number of bars that when provided with
a collector they give off electromotive force, and in which at least one winding
must be provided with a collector for giving off continuous current, while the
other winding or windings is or are divided into six or other number of bar
groups, a mode of connection of the windings having the object of either halving
the continuous current pressure so as to produce an equalising or three-lea
machine, or when both rotary phase current and continuous current are to be
given off, to determine the star point of the rotary phase current or to effect both
these ends, such-mode of connection being characterised by the fact that each of
the bar groups for connection with the uncut windings provided with a collector,
possesses a number of bars
wherein s is the total number of bars and a the
8
total number of current branchings occurring in all continuous current windings,
if used as such, substantially as described.
1 11
FIL
1
e T
7000
ABEL & IMRAY,
Agents for the Applicant.