Improvements in connection with the Windings of Dynamo Machines and Induction Motors.
Year: 1899

page_text: Date of Application, 16th June, 1899
Complete Specification Left, 6th Dec., 1899-Accepted, 16th June, 1900
PROVISIONAL SI'ECIFICATION.
Improvements in connection with the Windings of Dynamo
Machines and Induction Motors.
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 carried out
with cut continuous current windings of dynamo machines-or induction motors-
in order to obtain therefrom two rotary phase current pressures different in extent
from those which could be obtained with an uncut continuous current winding. For
this purpose any arrangement of continuous current winding with S bars and 2a
parallel circuits which are divided by 6a cuts, into 6a bar groups will serve.
The obtained bar groups are then connected together in various different ways for
obtaining the two above mentioned rotary phase current pressures.
Before proceeding to the explanation of the arrangements for the above purpose
it is necessary to give the following explanation as to the carrying out of the
cuttings and as to the diagrammatic illustrations required for indicating the separate
connections.
With every continuous current winding with optional number of poles and
armature wires (bars or windings) each wire produces a varying electromotive force,
which generally speaking is not of the nature of a sinus curve but of a nature
corresponding to the form of the magnetic field. As the wires (bars or windings)
are uniformly distributed upon the armature, either separately or in groups (for
instance in grooves) each bar will at a certain time have a different phase, i.e. a
different position relatively to the poles. In order to determine this position in the
simplest way, it is convenient to represent a sinus like distribution of the field in
the air space in order from the position of a bar relatively to a sinus field to be then
able to at once 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, as above stated, distributed uniformly over the periphery
of the armature, it is possible by the division of the entire periphery of the armature
into 6 times p equal parts, (where p denotes the number of pole pairs) to form groups
of bars in which no wire has a greater phase shift than 60° relatively to the other
wires of the same group, and which, taken as a whole (i.e. the sum of the electro-
motive force of all wires of one group) will produce electromotive forces that are
shifted 60° relatively to the electromotive forces of the contiguous groups. By this
division there will be obtained as many phases as there are groups, each sixth group
showing the same phase of the electromotive force, so that the number of the actual
phases is always reduced to six. It is possible with every continuous current
winding having quite generally speaking 2a parallel circuits, to obtain 6a separate

page_text: groups of bars, by cutting them open in 6a places, so that in each such group only
wires of the same phase occur, that is, only wires that lie in the sections 1, 4, 7, 10,
&c. or in the sections 1 and 4, 2 and 5 &c. or lastly, only in one section if the 6p
sections into which the armature was divided be consecutively designated by 1, 2, 3,
to 6p. In all cases and with each kind of winding it is however not possible to
obtain Ga perfectly equal groups of bars because it may happen that the armature
bar-number 8 is not divisible by 6a: in this case the division will be so made that
the separate phases i.e. bar groups have as nearly as possible the same number of
bars, which can in reality be very well effected without prejudice to the following
connections.
In Figs. 1 to 4 of the accompanying drawings are shewn diagrammatically various
practical examples of the manner of cutting open a winding at 6 points in the above
described manner.
Fig. 1 shews the arrangement for a four-pole machine with series winding
(a1, i.e. with only two parallel circuits), the total number of wires being so chosen
that it is divisible by 6a (therefore in this case 6).
Fig. 2 shews an analgous winding with a different number of bars, not divisible
by 6. Thus while the winding of Fig. 1, can be divided into 6 equal bar groups,
each with 7 bars, there are obtained with the winding according to Fig. 2, four bar
groups with 8 bars, and two bar groups, with 7 bars. This inequality is not
detrimental, the less so as in actual practice windings will seldom occur with so few
bars as are here assumed. In Fig. 3 is shown the division of the continuous current
winding into Ga phases of an eight polar machine with a = 2, that is, with four
parallel circuits, while Fig. 4 shews the same division for a six polar (p = 3) machine
with a =
1, that is, with two parallel circuits, the several six phases being again not
quite equal in this case.
Other examples of the division of the winding with other kinds of winding, need
not be described as the examples given of how the division with drum wave-winding
is to be effected will suffice.
As already stated, there are obtained by cutting open a winding at Ga points, Ga
bar groups, but always only with 6 phases, as a bar groups have the same phase.
It will therefore be possible in the following always to speak of 6 phases if it be
assumed that the a equal phases are connected in series or in parallel, or partly in
séries and partly in parallel and if the expression "a phase" be always assumed to
indicate a group of equal phases.
8
Ba
Each phase produces an electromotive force that is shifted 60° relatively to the
contiguous phases, and as furthermore each phase produces the same pressure, the
electromotive forces of the 6 phases can be represented by the sides of regular
hexagon as shown in Fig. 5 by the hexagon inscribed in the circle. The electro-
motive force of a phase results from wires, which produce relatively equal electro-
motive forces but which are however not of equal phase. As each wire produces the
same electromotive force and as on account of the uniform distribution of the wires
on the armature, each wire produces an electromotive force that is shifted through
the same small angle, and the sum of all these pressures gives the side of the
hexagon, it will be readily seen that the pressures of the separate wires can be repre-
sented by chords, for instance in Fig. 5, of the arc L-1, by dividing the are into 6a
equal parts and drawing in the chords. In Fig. 5 it is assumed that 7 wires form
together the electromotive force of one of the six phases, as is the case with the
winding diagram shewn at Fig. 1. In order to enable a continuous current winding
with 2a parallel circuits to be cut open correctly into 6a groups of wires, a common
cement is made at an optional point I and the winding is followed in one direction.
marking the commencement of the first bar with A¹. After passing over
bars, one
Ga
arrives at the second point of cutting 1, and the end of-the last bar already passed
8

page_text: over is marked e¹ while the commencement of the second phase yet to be passed over
8
6a
is marked a'. After passing over other bars, one arrives at the point of cutting II,
and so on.
The further designations are shewn in Figs. 1 to 5. If now 6 phases
have been passed over, and if a is greater than one, that is, if the winding has more
than two parallel circuits, one will again arrive at the beginning of a second first
If
phase, which is designated by A¹. The farther designations are shewn at Fig. 3.
however the machine has separated windings, the second, third, &c winding must be
cut open in the six points of the same potential as the first one.
The above being assumed, it will be evident that from now one can make use of
the diagrammatic representation of Fig. 5 for indicating the various arrangements
that can be carried out with the 6a bar groups.
As stated at the commencement, all the arrangements forming the subject of the
invention have the object of obtaining from a continuous current winding, cut open
in 6a points, two rotary phase current pressures of different value by connecting
together the obtained 6a bar groups in different ways.
Figs. 6 and 7 show connections which are produced by connecting each two
contiguous bar groups to from a double phase so that the phases A E¹, A² E²
and A³ E³ result. These three double phases are then so arranged according to Fig. 6,
that E3 is connected with ¹, E¹ with n² and E2 with 3, where n n² and n³ are three
points of the winding on the three phases at equal distances from A1 A2 A3. It is
therefore possible to take from a machine two rotary phase current pressures A¹ A².
and E E2 whose relative values can be varied by the choice of the points n¹ n² and n³
on the corresponding ares A¹ E', A² E² and A³ E³. The smaller pressure can serve
for example for lamps and the greater one for working motors.
In. Fig. 7 is shown an arrangement similar to that at Fig. 6 with the difference
that in this case the points E¹ E² and E³ are connected with the points n¹ n² and n³
different from the previous case.
Fig. 8 shews an arrangement produced by shifting the connections of the ends of
the three double phases, cyclically. Namely while, with the uncut continuous
current winding, A' is connected with E³, A2 with E' and A³ with E2: with this
arrangement A' is connected with E2, A2 with E3 and A3 with E¹.
In order with this arrangement to obtain two rotary phase current pressures, three
symmetrically situated points n¹ n² and n³ are assumed on the three double phases,
between which points a pressure proportional to the length n n² is then obtained.
This arrangement can be utilised like the counter connection with rotary phase
current motors, by connecting together permanently the points which give the
smaller pressure either directly or through resistances.
'n¹ n².
If namely the points n¹ n² n³ are permanently short circuited with each other, then
with one and the same turning moment of the motor an increase of slip in the
A¹ 12) 2 will be obtained. In order then to pass to the normal working
proportion
the greater pressure is utilised by short circuiting with each other the points A¹ A² A³.
In the following arrangements shewn at Figs. 9 to 15 on the other hand, a double
phase is always made out of two bar groups whose phases are shifted 180° by series
connection, so that here also only 3 resulting phases, namely the phases A¹ e¹ E² a²,
A² e E³ ³, and A³ ³ El a¹ are obtained.
These three phases are so connected in Fig. 9 that a¹ is connected with n³, a²
with n and a³ with n², where again n¹ n² and ³ are three points of the winding
situated at equal distances from E¹ E2 and E3 on the arcs E¹ a¹, E2 a² and E³ a³.
From this winding also two rotary phase current pressures can be taken, namely a
smaller one a¹ a² and a greater one A¹ A². In Fig. 10 an arrangement analogous to
Fig. 9 is shewn with the difference that here a' is connected with n² instead of n³, a²
with n³ instead of n', and a³ with n¹ instead of n².
Also in this case the ratio of the pressures can of course be altered, by a suitable
choice of the points n¹ n² and n³.
If n n and n³ be taken not upon the ares E¹ a¹ E² ² and E³ ³, but upon the

page_text: ares A¹ e¹ A² ² and A³ ³ at equal distances from A' A2 and A³, there will again be
obtained, as shewn at Figs. 11 and 12 two rotary phase pressures the amount of
which have the same proportion as a¹ a² to A¹ A2. The difference between the two
arrangements consists in that in Fig. 11 a¹ is connected with n², a² with n² and a³
with n³, while in Fig. 12 a¹ is connected with n², a² with n³ and a³ with n¹.
-
Figs. 13 and 14 shew two special cases, in which the points n¹ n² n³ are so chosen
as to coincide with E1 E2 E³.
In Fig. 13 a¹ is connected to E², a² with E3 and a³ with E¹, while in Fig. 14 a¹ is
connected with E3, 2 with E¹ and a³ with E².
In Fig. 15 the three phases are connected in a triangle, which, arrangement is
produced if the three point n¹ n² and n³ be so chosen as to coincide with A¹ A²
and A³.
In order also in this case to obtain two rotary phase current pressures, there must
be taken on the three double phases three points that are indicated by n¹ n² and n³
Fig. 15. This arrangement can be employed as counter connection with the rotary
phase current motors, the three points which give the smaller pressure 'being
permanently connected together either directly or through resistances. If namely,
the three points n¹ n² and n³ which give the smaller rotary phase current are
permanently short circuited with each other, there will be obtained with one and the
same turning moment of the motor, a greater slip. increased in the proportion
(AL A²²
\n' n²
In order then to pass over to the normal working, the greater pressure is employed
by short circuiting the points A¹ A2 and A³ with each other.
In the arrangements to be last considered, a double phase is always produced from
2 bar groups whose phases are shifted 180°, by parallel connection, so that three
double phases are again obtained as is for example shown at Fig. 16.
If now these three double phases are connected either in star connection Fig. 16,
or in triangle connection, then provision must be made by assuming 6 points on the
6 bar groups for obtaining the smaller rotary phase current pressure.
In Fig. 16 is shewn how this is to be done, the lengths m n representing the
smaller pressures and the lengths A¹ A² the greater pressures.
This arrangement is also applicable as the counter connection for rotary phase
current motors; if namely the six points which are to give the smaller rotary phase
current pressure be connected together in pairs either directly or through resistances
in such manner that those points which are situated on a double phase are short
circuited with each other, there will be obtained with a certain turning moment a
A¹
than that which would be
slip which will be greater, in the proportion (2012) 2
obtained in short circuiting the points A¹ A² and A³.
101
CT1000
Improvements in connection with the Windings of Dynamo
Machines and Induction Motors.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Build- 45
ings, in the County of London, Consulting Engineer and Chartered Patent
Agent, do hereby declare the nature of this invention (as communicated to me

page_text: 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 ascer-
tained in and by the following statement:-
This invention relates to arrangements and inodes of connection to be carried out
with cut continuous current windings of dynamo machines or induction motors in
order to obtain therefrom two rotary phase current pressures different in extent from
those which could be obtained with an uncut continuous current winding.
For this purpose any desired continuous current winding can be used, it being
quite immaterial whether it be a drum winding or a ring winding, and whether it
consist of one or more closed windings; also whether, with a large number of pole.
pairs, the separate parts of the winding are connected in series or in parallel or
partly in series and partly in parallel.
As is known, there is in every closed continuous current winding at least one
branched current. Thus in the simplest case of a bi-polar machine with a closed
continuous current winding this may be arranged so that not all bars or coils of the
winding work in series, but that two halves of the winding are connected together in
parallel. If a bi-polar machine be provided with several short circuited continuous
current windings, there will be a branched current in each of these windings.
If the machine is a multi-polar one, the number of branched currents will depend
upon the kind of winding. Thus, for example, with a purely series connection of the
bars or coils of a closed winding, only a single branched current will occur, as in a
bi-polar machine. With a purely parallel connection there will occur as many
branched currents as there are pairs of poles. By forming a mixed parallel and series
connection the number of branched currents can be varied at will. As therefore, in
consequence of each branching of a current, two winding sections are produced that
work parallel with each other, and as at least one branch current must be produced,
the number of the parallel working sections of a continuous current winding can,
generally speaking, always be expressed by an even number 2*.
In the following it is intended to shew that every continuous current winding can
be used for carrying out the present invention whereby two rotary phase current
pressures of different extent are produced therefrom.
For this purpose the continuous current winding must first be divided into sections
by cutting. The number of such sections depends entirely upon the number of the
current branches which would occur in the winding to be cut, if it were to be used
as continuous current winding.
If the number of bars or coils of a continuous current winding be represented by 8,
the number of current branches with a and consequently the number of the winding
sections which are connected in parallel with 2", then 6* cuts are required, by which
the total winding is divided into 6 parts. The connections which have to be made
in these 6 parts in order to obtain two rotary phase current pressures, may however,
in all cases as will be shewn in the following-be led back to the simplest case of
a bi-polar machine with a single branch current, that is with a = 1.
The obtained bar groups may be connected together in various different ways for
obtaining the two above mentioned rotary phase current pressures.
Before proceeding to the explanation of the arrangements for the above purpose it.
is necessary to give the following explanation as to the carrying out of the cuttings
and as to the diagrammatic illustrations required for indicating the separate
connections.
With every continuous current winding with optional number of poles and armature
wires (bars or windings) each wire produces a varying electromotive force, which,
generally speaking, is not of the nature of a sine curve, but of a nature corresponding
to the form of the magnetic field.
As the wires (bars or windings) are uniformly distributed upon the armature, either
separately or in groups (for instance in grooves) each bar will at a certain time have a
different phase, i.e. a different position relatively to the poles. In order to determine
B.

page_text: this position in the simplest way, it is convenient to represent a sine like distribution
of the field in the air space in order from the position of a bar relatively to a sine
field to be then able to at once 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, as above stated, distributed uniformly over the periphery
of the armature, it is possible by the division of the entire periphery of the armature
into 6 times p equal parts, (where p denotes the number of pole pairs) to form groups
of bars in which no wire has a greater phase shift than 60° relatively to the other
wires of the same group, and which, taken as a whole (i.e. the sum of the electro-
motive force of all wires of one group) will produce electromotive forces that
are shifted 60° relatively to the electromotive forces of the contiguous groups. By
this division there will be obtained as many phases as there are groups, each sixth
group shewing the same phase of the electromotive force, so that the number of
the actual phases is always reduced to six.
If the division of the armature winding be effected in the above described
manner, by only considering the number of pole pairs and making 6 p cuts at
equal distances apart, there will be obtained in most cases more cuts than are
absolutely necessary.
Thus, by cutting a 6 pole armature winding (p=3) with purely series connec-
tion, (a 1) there would be obtained 6 × 3 winding sections of which the first, seventh,
thirteenth, as also the second, eighth, fourteenth &c., would have equal phases. The
number of cuts: 6 ×p: 18, is, however, in this case much greater than the minimum
number of cuts that are necessary.
By the following examples it will be clearly shewn that the number of poles do not
determine the number of cuts, but only the number of branch currents. It will be
seen that it is possible, with every continuous current winding with, generally
speaking, 2x a parallel circuits (a branch currents) by cutting the same at 6a points,
to obtain 6 separate groups of bars or coils, in such manner that in each such group the
bars or coils whose phases are most shifted relatively to each other, will have
a phase-shift of at most 60º.
With a 6 pole machine with purely series
connections (p=3 a=1) it will therefore not be necessary to make 18 cuts, but that
6 cuts will be sufficient, dividing the winding into 6 sections by means of which all
the rotary phase current connections necessary for the purposes of this invention can
be obtained.
In all cases and with each kind of winding it is however not possible to
obtain 6a perfectly equal groups of bars, because it may happen that the armature
bar-number 8 is not divisible by 6a; in this case the division will be so made that
the separate phases, i.e. bar groups, have as nearly as possible the same number of
bars, which can in reality be very well effected without prejudice to the following.
connections.
.
In Figs. 1 to 4 of the drawings accompanying my Provisional Specification are
shewn diagrammatically various practical examples of the manner of cutting open a
winding at 6 points in the above described manner.
a
In these figures are shewn diagrams of the connections of four drum windings with
wave-windings. In all the figures denotes half the number of the bars; p
the number of pole-pairs; a the number of the branch currents; 2ª the number of the
winding sections which operate parallel when using the winding for producing
continuous current; y¹-y² the pitch of the winding, i.e. the number of bars which
have to be passed over in connecting one bar with another of the same winding.
Fig. 1 shews the arrangement for a four-pole machine with series winding (a=1, i.e.
with only two parallel circuits, the total number of wires being so chosen that it is
divisable by 6a (therefore in this case 6).
Fig. 2 shews an analogous winding with a different number of bars, not divisible
by 6. Thus while the winding of Fig. 1 can be divided into 6 equal bar groups,
each with 7 bars, there are obtained with the winding according to Fig. 2, four bar

page_text: groups with 8 bars and two bar groups, with 7 bars.
This inequality is not
detrimental, the less so as in actual practice windings will seldom ocour with so few
bars as are here assumed.
Fig. 3 shews the division of the continuous current winding of an 8 pole machine.
The winding shews a mixed series-parallel connection in which a=2.
Fig. 4 shews the same division for a 6 pole (p=3) machine with a = 1 (purely
series connection) that is, with two parallel circuits, the 6 separate phases not being
perfectly equal.
Other examples of the division of the winding with other kinds of winding, need
not be described as the examples given of how the division with drum wave-winding
is to be effected will suffice.
From these examples it will be seen that in order to divide a continuous current
winding with, generally speaking, s bars and 2a parallel winding sections into 6
times a groups of the above described kind, the proceeding can be as follows:-
8
The winding is cut open at any desired point, and is followed along the connected
bars or coils in the one direction designating the commencement of the first bar
by A¹. After passing along bars, the next point for cutting is arrived at, and the
6.a
end of the last bar passed over is designated by e¹. The commencement of the next
bar to be passed along, with which the next winding section begins is designated
by a
In order to avoid misunderstanding, it should be here again stated that in passing
8
θα
8
δα
8
6.a
along
bars, the continuous winding has to be followed, and not contiguous
bars, which belong to other windings.
Starting from a¹, one arrives after passing along other bars, to the next point
of cutting, the end of the last bar passed over being marked E, and the commence-
ment of the first bar of the next section with A. Continuing in this manner, and
designating the points of cutting with (e, α₂) (E₂, A₁), (е, α₂) one arrives, if a = 1,
after passing along 6 phases, back to the point of starting, the end of the last bar
being designated by E.. If, however, a is greater than 1 (as in Fig. 3), then after
passing along the sixth winding section, one does not arrive at the point of starting,
but to a bar which has the same phase as the starting bar. From this bar, the
beginning of which is designated by A₁₁, the division of the winding is continued in
the same direction, always making a cut after passing over bars.
8
6a
In the example shewn at Fig. 3, where a = 2, one arrives at the starting point
again after passing over the twelfth winding section. The end of the seventh
section is designated by e₁₁, the beginning of the eighth section by a₁₁, the end of this
by E¹, the beginning of the ninth with A¹, &c., &c. It will be readily seen from
Fig. 3 that the winding section A₁₁ e₁₁ has the same phase as the winding
section A, e,; the section a¹, E¹, the same phase as the section a₁ E₁ &c. Thus
speaking generally, one obtains 6 times a sections, of which the 1st, 7th, 13th &c.,
then the 2nd, 8th, 14th &c., and lastly the 6th, 12th, 18th have the same phases. Of
the 6a sections a sections generally have the same phase, so that practically only 6
sections are produced having their phases shifted 600 relatively to each other, which
are repeated a times. In the following therefore, only 6 winding sections will be
referred to which are shifted in phase through 60°, it being assumed that a sections
of equal phase are connected either in series or in parallel, or partly in series and
partly in parallel, and form together a winding element. Such a winding element I
will in the following speak of as "phase," for brevity's sake.
If the machine has several separate windings, of which each one is closed in itself,
each of these has to be cut open in the above described manner.
In that case s must be taken to signify the total number of all the bars or coils,
and a the total number of all branch currents in all the windings, the cutting being

page_text: effected in an analogous manner in all the separate windings. Each winding is thus
divided into as many times six sections as it has branch currents. The number of
sections into which the entire winding is divided is, as before, equal to 6 times a.
Each set of a sections of equal phase form together a phase."
<
In order to render perfectly clear the connections which can be effected with the
"phases" thus obtained in order to produce two rotary phase current pressures of
different extent, a mode of representation has been chosen which renders it possible
to read off the pressure existing between two points of the rotary phase winding
directly from the diagram.
8
6a
Each phase produces an electromotive force that is shifted 60° relatively to the
contiguous phases, and as furthermore each phase produces the same pressure, the
electromotive forces of the six phases can be represented by the sides of regular
hexagon as shewn in Fig. 5 by the hexagon inscribed in the circle. The electro-
motive force of a phase results from wires, which produce relatively equal electro
motive forces but which are however not of equal phase. As each wire produces
the same electromotive force and as on account of the uniform distribution of the
wires on the armature, each wire produces an electromotive force that is shifted
through the same small angle, and the sum of all these pressures gives the side of
the hexagon, it will be readily seen that the pressures of the separate wires can be
represented by chords, for instance in Fig. 5, of the arc L-1, by dividing the arc
into equal parts and drawing in the chords. In Fig. 5 it is assumed that 7 wires
form together the electromotive force of one of the six phases, as in the case with the
winding diagram shewn at Fig. 1.
8
6a
In order that with each mode of connection the pressure between two points of the
rotary phase current winding obtained may be given directly by the distance apart
of these points, as in Fig. 5, the separate phases are shifted parallel to themselves
from the position which they assume in Fig. 5 into the particular position of the
connection required.
Figs. 6, 7 and 8 shew such connections, which are produced by shifting each two
of the six phases A₁ ₁₁; α₁ E₁; А, lq; αq Eą; Az ez; 3 E3; through 60° relatively to
each other and connecting then to form a resultant phase so that the resulting
phases A, E₁; A, E,; A, E,; have to be dealt with, which in the following will be
called "double phases" for brevity's sake.
The double phase A, E, by way of example, is produced by the connection of the
phases A, e, and a, E, shifted 60° relatively to each other; the resulting pressure is
therefore given by the distance A, E, which is the geometrical resultant of the dis-
tances A, e, and e, E₁. The resultant pressures of the three double phases are each
shifted 120° relatively to the others.
I
These three double phases are according to Fig. 6, so connected that E, is con-
nected with n, E, with n, and E, with n,, where n₁ n₁ n, are three points of the
winding sections which are equidistant from the ends A, A, and A..
Owing to the fact that, unlike the existing star connections where the three
corresponding ends E, E, E, of the three double phases, each shifted 120° are con-
nected directly with each other at one point, such ends in the present case form a
triangle, it is rendered possible to take off two different rotary phase current pressures.
If the machine operates as a rotary phase current generator and if the consumption
circuits are connected at A, A, A, and n₁ ng n₂, there will exist between the two first
circuits a pressure: A, A,, and between the two last circuits a pressure n₁ n. The
smaller pressure can now be used for electric lighting, and the greater for driving
motors.
The proportion between the pressures can be varied at will by suitably varying the
positions of the points n, m, n, on the arcs A, E, A, E, A, E,.
Fig. 7 shews a mode of connection similar to Fig. 6, with the difference that in
this case the points E₁ E, E, are connected to the points n₁ n n in a different
nannan

page_text: Fig. & shews a mode of connection which may be supposed to have resulted from
the arrangement at Fig. 5, by shifting the connections of the ends of the three
resultant phases A, E, A, E, A, E,, so that the end E₁ of the first phase A₁ E₁ is con-
nected with the beginning A, of the third double phase A, E,, the end E, with A
and E, with A,
In order, with this arrangement, to obtain two rotary phase current pressures, three
points ni no n, situated symmetrically on the three double phases are taken, between
which points a pressure will then be obtained proportional to the distance n₁ n
This arrangement can be used in particular for the winding of the rotating part of
a rotary phase current motor.
As is known; it is generally endeavoured, in order on starting the motor not to
produce too strong a current in the rotor, to prevent the armature pressure by con-
necting the parts of a single phase in opposition to each other at first and then when
the armature has attained a certain speed, to let them work in parallel or in series.
This action can be obtained with an armature winding connected as at Fig. 8, in a
much more perfect manner than heretofore, by first so choosing the three points
which such a winding has to be short circuited or connected through resistances, that
the induced armature pressure is correspondingly small, and then by connecting the
points. E, E, E, to allow the greatest pressure to act. If for instance at first the
centres of the three double phases were to be short circuited or connected by resist-
ances, three circuits would be obtained in each of which two equal pressures would
act in opposition to each other. Consequently no current would flow through the
armature.
If the points n, m, n, be connected by suitable small resistances, three circuits will
be produced A, n₁ n₂ E₁; A₂ ng n₂ E; A₂ ng n₁ Е₁, in which the electromotive forces
act partially counter to each other. The resulting pressures in these three circuits
are directly proportional to the distances n₁-n, n-n₂, n₁—n₁.
If finally the points A, A, A, be connected by resistances, or be short circuited,
there will be obtained three circuits: A, E, A₁; A, E, A₂; A, E, A, in which the
electromotive forces will be proportional to the distances A₁-E₁, A, E₁, A.-E..
In the following arrangements shewn at Figs. 9 to 15 on the other hand, a double
phase is always inade out of two bar groups whose phases, are shifted 180° by series
connection, so that here also only 3 resulting phases, namely the phases A, е₁ E, α,
E, as and A, 3 E, a, are obtained.
A,
These three phases are so connected in Fig. 9 that a, is connected with n₂, a₂ with
n, and a, with no, where again n, n, and л, are three points of the winding situated
at equal distances from E, E, and Eg on the arcs E₁ a₁, E, a, and E, a..
From this winding also two rotary phase current pressures can be taken, namely a
smaller one a, a, and a greater one A, A. In Fig. 10 an arrangement analogous to
Fig. 9 is shewn with the difference that here a, is connected with n₂ instead of n
with ng instead of n₁, and with instead of n
Also in this case the ratio of the pressures can of course be altered by a suitable
choice of the points n₁₂ and
ng.
If n, n, and n, be taken not upon the-arcs E, α, E₂ α₂ and E α, but upon the
arcs A, e, A, e, and A, e, at equal distances from A, A, and A, there will again be
obtained, as shewn at Figs. 11 and 12 two rotary phase pressures the amount of
which have the same proportion as a₁ a₁ to A₁ A₂. The difference between the two
arrangements consists in that in Fig. 11 a, is connected with n₁, a with na and
with ns, while in Fig. 12 a, is connected with 11₂, a with ns and a3 with 12.
Figs. 13 and 14 shew two special cases, in which the points n₁ n₂ ng are so chosen
as to coincide with E, E, E,.
Az
In Fig. 13 a, is connected to E, a, with E, and a, with E₁, while in Fig. 14 a, is
connected with E., a₂
with E
with E, and
"
The arrangements shewn at Figs. 67 and 9 to 14, are generally similar and are
mainly intended to be used with generators which are used both for electric lighting
and for driving motors.
In Fig. 15 the three resultant phases are connected in the usual triangular mesh

page_text: form. In order also with this mode of connection to be able to obtain two different
rotary phase current pressures, there must be chosen on the three resultant phases
three points n, n, n, which are equidistant from the points A, A, A,. This arrange-
ment is particularly suited for the winding of the rotating part of a rotary phase
current motor, as with the same, on starting the motor a similar action can be
obtained as with the arrangement with opposing pressures.
But while with the arrangement at Fig. 8, by short circuiting or connection of
three points, the pressure can be varied between the limits of zero and maximum,
with the arrangement at Fig. 15 the smallest obtainable pressure is about equal to
half the maximum pressure. If namely the three points which have to be short
circuited with each other or are connected by resistances, if the winding is to be
divided into three circuits, be so chosen as to lie in the middles of the three resulting
phases A, a A, a, A, a₁; there will be produced three circuits A₁ & Е₁ A₁; A₂ e̟
E A₂; A E Ag, in which the electromotive forces are proportional to the dis-
tances E, E, E₁—E, E‚—E₁.
If the points n, n n be taken to the right or the left hand of the resultant
phases, the pressures in the circuits which are produced by short circuiting or con-
necting the points n, non, are proportional to the distances n₁-n, n-n₁, N₁—N₁.
The maximum pressure will be obtained on short circuiting the points A, A, A,. The
maximum pressure is proportional to the distances A₁-A., A₂-A¸‚ A₂—A₁.
=
In the last arrangements to be considered there are always produced from each two
bar groups, whose phases are shifted 180°, one resultant phase, so that one has again
to deal with three double phases, as is for example shewn in Fig. 16. If now these
three double phases A-e, a₂-E; A₂-e α-E; A-a-E₁ are connected
either in star (Fig. 16) or in triangle, then by taking 6 points on the 6 bar-groups,
one can also obtain the smaller rotary phase current pressure.
Fig. 16 shews how this is to be done. If the points A, A, A, be short circuited or
be connected together by resistances, or if they be connected with the star point O,
there will be obtained for each phase the greater pressure OA, or OA, or OA. But
if two points of the same phase be connected with each other, that is, m₁ with n₂,
m, with n, m, with n, by means of the leads m, n, m, n, m, n₁ there will be ob-
tained the circuits A, m, n,, O m₁ n₂, A₂ m₂ ng, O. mg 13, A3 m² ₁, O m, n₁, and the
smaller pressures m, n, m, n, and m, n₁.
This arrangement can, similarly to those of Figs. 8 and 15, be used for the rotor
of a rotary phase current motor, the smaller pressure being used on starting the
motor, and the greater one when the motor is working normally.
.
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 dynamo machines and induction motors, the arrangement of the windings in
such manner that by means of a continuous current winding.with 2a parallel circuits,
and cut open at 6a points, two rotary phase current pressures can be obtained there-
from, the arrangement being such that 6 phases are produced from the 6a equal or
nearly equal bar groups formed by the 6a cuts, each set of a bar groups of equal
phase being combined to form a single phase either by parallel or series connection,
or both combined, the said arrangement being furthermore combined with either of
the following features:-
(a) A double phase is formed of two contiguous phases, and the double phases so
obtained are connected as shewn at Figs. 6, 7 and 8 of the drawings, the smaller
pressure being always taken from three points of the three double phase systems,
while the greater pressure is always taken from three of the six ends of the three
double phases; or (b) A double phase is formed of each two phases shifted 180°, by
connecting the same in series, and the three double phases thus obtained are
connected as shewn at Figs. 9, 10, 11, 13, 14 and 15, the smaller pressure being
again taken from three points lying symmetrically upon the three double phase
systems, while the greater pressure is always taken from three of the 6 ends of the
:

page_text: three double phases; or (c) A double phase is formed of each two phases shifted 180°
by connecting them in parallel, and the three phases thus obtained are connected
either in star (Fig. 16) or in mesh connection, the smaller pressure being taken from
two points of the same double phase, while the greater pressure is in the case of star
connection of the double phases, taken from three of the six ends of the three double
phases, and in the case of mesh connection of the double phases, it is taken from the
six ends of the three double phases.
1
בד.
1
1000