Improvements in Alternating Current, Simple or Polyphase, Dynamo Electrio Machines.
Year: 1894

page_text: Date of Application, 1st May, 1894-Accepted, 7th July, 1894
COMPLETE SPECIFICATION.
Improvements in Alternating Current, Simple or Polyphase, Dynamo
Electrio Machines.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, (a com-
munication to me from abroad by André Blondel, and Sautter, Harlé et Cie., of
Avenue Suffren, Paris, in the Republic of France,) do hereby declare the nature
of this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
The novel system of simple or polyphase alternating current machines forming
the object of the present invention is founded upon the use of the disc form both
for the inductor system and the induced system.
The word "disc" is used to signify a portion of a soft iron cylinder of suitable
thickness traversed by lines of force from one face to the other whatever may be
their path in the interior of the soft iron.
In the following description the word "inductor" is by analogy with continuous
current machines used to signify that portion of the machine in which the magnetism
is stationary or at least is subject to very slow displacement.
The word "armature" is used to signify that portion of the machine in which
the magnetic field varies or is subject to displacement with the same periodicity as
the utilised alternating currents. The armature is therefore the current generating
portion in a generator and the receiving portion in a motor.
The armature and the inductors have soft iron cores in all the machines described
in the present Specification. They are moved relatively to each other either by.
rotating the armature or by causing the inductors to rotate about their common
axis.
They may also both be stationary the moveable portion being an unwound disc
of discontinuous soft iron.
This type is called "machine with rotating iron disc."
The two principal advantages obtained by the system herein described are:-
facility for reducing the angular velocity to a small value and the diminution of the
volume of iron submitted to hysteresis which allows specific induction to be
augmented and self induction to be reduced. The weight of armature copper is
greatly reduced whilst its specific utilisation increases. The armature and the
inductors are easy to inspect and to repair.
In this present system the method of constructing the armature is the same
whether the machine be synchronous or non-synchronous, the inductors only are
different.
The description comprises therefore four portions:
I. The armature for a synchronous or non-synchronous machine.
II. The inductors for a synchronous machine.
III. The inductors for a non-synchronous machine.
IV. The machine with rotating iron disc.
:
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a diagram illustrating the system.
Figure 2 shows the general arrangement of a disc armature with flat bobbins with
discontinuous winding.

page_text: Figures 9, 10, 11 and 12 show several arrangements of continuous winding with
flat bobbins for monophase or polyphase currents.
Figures 13 and 14 show discontinuous winding with oblique bobbin arrangement
for monophase or polyphase currents.
Figures 15, 16, 17, 18 and 19 show continuous winding with oblique bobbin
arrangement for monophase or polyphase.currents.
Figures 20 and 21 show discontinuous winding with involute bobbin arrangement
for monophase or polyphase currents.
Figures 22 and 23 show discontinuous winding in involute form of a disc with
iron core for monophase or polyphase currents.
Figure 24 shows diagrammatically discontinuous winding for the inductors of a
synchronous machine.
Figures 25, 26, 27, 28, 29 and 30 show inductors with discontinuous winding
made of bands of sheet iron wound for synchronous machines.
Figures 31, 32, 33, 34 and 35 show inductors with discontinuous winding made
of plates cut separately and fastened together for synchronous machines.
Figures 36, 37, 38, and 39 show massive inductors in iron, cast iron or steel with
discontinuous winding for synchronous machines.
In Figures 36 and 38 these inductors are mounted with a suiuable armature.
Figure 40 shows an inductor made of toothed sheet iron with continuous winding
for synchronous machines.
Figures 41, 42, 43, 44, 45, 46 and 47 show inductors with bobbin arrangements
in closed helices for non synchronous machines.
Figures 48, 49 and 50 show this system applied to machines with rotating
iron disc.
Figure 51 shows in section a monophase or polyphase current generator.
Figure 52 shows in section a monophase or polyphase non synchronous motor.
In these figures:
A is the armature, consisting of a soft iron disc, provided with bobbins and
moved relatively with respect to the inductors about its axis.
A are polar projections on the armature with discontinuous winding, they are
equal amongst themselves and are equal in number to that of the inductor
poles.
A is the core of the armature with continuous winding formed of lamina of
sheet iron.
A is the core of an armature with involute discontinuous winding.
A is a disc armature with flat bobbin winding, or oblique or annular
winding.
B are the exciting inductors with their bobbins.
B'B' show polar projections of inductors with discontinuous winding, cat in the
same sheet of iron.
B is a roll composed of a band without teeth.
B are plates inserted between the spirals on the band B³.
B* B* B* B* B* B* are inductors with discontinuous winding formed of plates
fastened together.
Bare massive inductors.
B¹ is a crown of inductors formed of an assemblage of toothed sheet iron.
B1 are soft iron inductors of non synchronous machines.
B are fixed portions of the machine, formed of bands or separate plates, or of
solid iron, cast iron or steel.
bare bolts or hooks retaining the turned down ends of the bobbins upon the
cylindrical faces of the armature.
C is the axis of rotation.
D is the hub supporting the armature.
D' is the hub supporting the inductor.
E are armature bobbins.
e are armature bobbins for discontinuous winding and monophase currents.

page_text: In multipolar machines the windings are reproduced symmetrically for each
field. Windings of the same phase may be grouped either in series or in parallel.
For bisecting the phases according to the ordinary method wires of different
section are employed according as the bobbins are mounted in star or in
-polygon.
The two methods of winding, the discontinuous and the continuous, are both
applicable to the disc provided with flat bobbins. The first method has the
advantage of facilitating the repair of the bobbins which are all removeable or
interchangeable. The bobbins of the two faces of the disc may also be connected
in series or in parallel.
To produce the diphase current for example, it is sufficient to place the bobbins
such as ee and ee in two superposed groups or to adjust those of one face e* *
half a polar interval with respect to e e¹. This last arrangement is very
advantageous in that it does not modify the construction used for the monophase
current armature.
The phases may also be bisected and the bobbins e ed wound in a contrary
direction by connecting them in series. The second group 'e then supplies the
second circuit of the diphase current. One thus avoids superposing the bobbins
as et e¹.
The alternate inductor poles B" in the machine Figures 38 and 39 may be
adjusted not at a polar interval but at a polar half interval, the armature disc with
flat bobbins will produce a diphase current upon its two faces.
The same arrangements are moreover applicable to the production of a current
with any number of phases.
"
In continuous winding with flat bobbins the radial grooves in the armature are
equidistant and their number for each polar space is an odd or even multiple of
the number of phases to be produced if it be wished to obtain a polyphase
current.
To produce the monophase current the first group 8 of the windings encircles
one or n teeth, the second group e encircles 3 or + 2 teeth, the third group €10
encircles 5 or n+4 teeth and so on. The second bobbin e eelo wound in a
contrary direction is connected in series or in parallel with the preceding.
A polyphase current is obtained by superposing on the preceding winding similar
windings adjusted to a suitable angle.
Continuous winding with flat bobbins may also be applied to a smooth armature
for monophase or polyphase currents.
In the disc armature with iron core and oblique bobbins the two faces of the
armature no longer work independently; they are united by junction pieces placed
obliquely upon the cylindrical surfaces, or distorted as shewn in Figure 17.
The discontinuous winding (bobbins el el) is intended for monophase currents.
By superposing other similar windings, adjusted to a suitable angle, polyphase
currents are obtained.
In the continuous winding, for triphase currents, for example, the grooves F are
numbered 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6 upon one face and 11, 21, 31, 41, 51, 6',
1, 2, 3, 4, 5, 61 upon the other face. The sign + corresponds to a pole of even
order, the sign to a pole of odd order.
The winding occupies the grooves 11, 1, 21, 2 etc. coupled in series; the
winding e, the grooves 31, 3, 41, 4 etc.; the winding e, the grooves 51, 5, 61, 6 etc.
The same arrangement allows a monophase current to be obtained by limiting it to
a single winding e³.
Continuous winding may also be imbricated (Figures 18, 19) and will have the
same properties.
The oblique bobbins may be formed by placing wire, cabled wire strips, ribbon,
bars in grooves, holes or upon a smooth armature.
The bars may be connected by flat blades of copper arranged upon the cylindrical
surfaces and shaped to adapt themselves to the curvature of the disc.

page_text: In the disc armature with iron core and involute bobbin arrangement
(Figure 20-21) the discontinuous winding is alone employed. The grooves F in
involute placed symmetrically upon the two faces cut each other two and two at
the outer and inner circumference. The undulating bobbins e¹ of wire or strips
are placed alternately upon each face and joined from one face to the other by a
rectilinear junction piece parallel to the axis of the disc. As thus represented the
armature furnishes a monophase current. A polyphase current is obtained by
placing on the armature other similar windings adjusted to a suitable angle. -
The disc armature with iron core in involute form only includes discontinuous
winding. The iron core formed of plates in involute form is reduced to a minimum.
The bobbins ee" of the two circuits are placed alternately upon the two faces;
they are as represented for producing diphase currents. A polyphase current of any
order would be obtained with a number of circuits equal in number to the number
of phases to be produced.
Inductors for synchronous machines with discontinuous winding may be con-
structed of rolled bands of sheet iron cut out separately and fastened together
in iron, cast iron or steel blocks of any shape for example trapezoidal, rectangular,
circular &c.
The inductors of rolled bands have on them polar projections B₁ B' obtained
either by previously cutting the band (increasing the intervals according to the
variable winding radius) which allows the poles at the two faces of the machine to
be manufactured at one time or by forming in the previously rolled up band radial
grooves in which the exciting bobbins are placed.
In the arrangement shewn in Figure 30 the projecting inductor poles formed by
the plates B have the same outer shape but less density of laminated mass.
The inductors formed of fashioned plates are made up of U shaped plates either
of varying sizes to compensate the varying radius of the winding or of a single
size such as B united upon the inner circumference and the middle of which are
upon radii traced at equal distances from the poles leaving between each bundle an
empty V shaped space, or in three or several sizes such as B B7 B8 leaving between
them step like empty spaces. The exciting bobbins g' are placed in the spaces
which separate the two sheet iron U shaped jambs.
The empty spaces of the bundles may also be filled by interposed rectangular
plates B placed with crossed joints between the plates B³.
The inductor poles may also be formed of rectangular plates B1 encased in the
notched cheeks G³.
These several arrangements cause the parasitic currents tending to be produced
in the inductors by the variation of the field due to the discontinuous winding of
the armature to be suppressed.
Massive inductors B" the use of which simplifies the construction of the machines,
may be arranged in such a manner as only to carry a single exciting bobbin
common to the whole system the polarity remaining the same upon each face of
the armature. The inductor poles N and S may be placed facing each other or
adjusted to a polar interval which allows a disc armature with continuous or
discontinuous annular winding to be employed, or again it may be adjusted to
a polar demi interval to produce diphase currents, each face of the armature with
flat bobbins constituting one of the circuits at 180°.
Inductors for synchronous machines with continuous windings are formed of a
band of toothed sheet iron B" provided with teeth uniformly distributed.
The winding may be effected with flat oblique radial or annular bobbins as in the
disc armature with continuous winding with teeth; it is however traversed by a
continuous current. The turns distributed upon the angular portion which
corresponds to a complete magnetic field are connected in such a manner as to form
only two single bobbins having contrary magneto motive forces.

page_text: III. INDUCTORS FOR NON SYNCHRONOUS MACHINES.
The inductors for non synchronous machines may be formed of bands of sheet
iron, solid iron, cast iron or steel.
They are necessarily with continuous winding and are either in flat bobbing or
in a flat ring.
.
The bobbins may be made with insulated conductors, the different flat or annular
bobbins being connected in such a manner as to constitute a certain number of
circuits, the bobbins of the same row in the several fields may be coupled in series
or in parallel.
The circuits obtained are closed in short circuit upon themselves or are connected
to insulated rings fixed upon the axle thus allowing the currents to be collected for
use in any manner, in particular for use in another machine or for interposing in
their circuits rheostats self inductions, condensers etc.
The bobbins may also be made up of closed turns formed by copper bars g.
soldered to copper rings g' or closed in short circuit upon themselves.
These two types of bobbins may be associated upon the same machine. The
soft iron core of the inductors may also be completely enveloped in a continuous
metal covering which has exactly its shape and of which the portion which covers
the inner face may be a grating fitting into the grooves in the core.
IV. MACHINES WITH ROTATING DISC.
The machines with rotating iron disc may be constructed for synchronous or
nonsynchronous simple or polyphase currents.
...The exciting bobbins and the armature-bobbins may be connected either upon
the disc A which remains stationary, the parts B composed of masses of soft iron
these alone being moveable, or upon the parts B, in this case fixed, the soft iron
disc A. alone being moveable.
In the first arrangement (Figure 48) the exciting bobbin g is fixed the
upon
armature A. The core B of the inductors rotates in the interior of which
.remains stationary, the current is generated in the same way as in the types shown
in Figures 36 and 38. The inductor poles may be placed opposite each other or
adjusted at intervals.
In the second arrangement (Figures 49 and 50) the fixed portions B carry
round the poles N and S the exciting bobbins g' and the armature bobbins e
-alternately.
The rotation of the disc A' changes the direction of the flow in the armature
poles by producing the variation necessary for creating the induced electro
motive force.
The machines with rotating iron disc does away with the rings, rubbers or
moveable contacts, which gives great facility in the insulation of the armature and
inductor circuits.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
-claim is:-
1. The combination in simple or polyphase alternating current synchronous or
nonsynchronous machines, of a system of disc armature with iron core covered
with flat bobbins or provided with oblique radial bobbins or with bobbin arrange-
ments in the form of involutes or with bobbin arrangements the iron core of which
is itself formed of plates in form of involutes, each of these bobbin arrangements
being discontinuous or continuous according as the armature is itself provided with
or is without apparent poles and being formed according to any one of the methods
.described and shewn.
2. The combination in simple or polyphase alternating current synchronous

page_text: machines of a system of inductors made of rolled bands; shaped plates or massive
iron, cast iron, or steel for discontinuous winding or of toothed bands for continuous
winding, excited by a continuous current, placed laterally against the smooth faces.
of the armature disc; the windings being effected according to any of the methods.
described and shown.
3. The combination in simple or polyphase alternating current non synchronous
machines of a system of inductors in the form of flat discs or rolled bands in
massive cast iron, iron or steel covered with bobbin arrangements of insulated
conductors with flat or annular winding closed in short circuit upon themselves or
connected to an outer circuit or covered with a bobbin arrangement with closed.
turns formed of copper bars soldered between them.
4. The combination of any one of the forms of disc armature described and.
shown with any one of the forms of inductors described and shown for the
construction of a simple or polyphase alternating current synchronous or non.
synchronous generator or motor with moveable armature or with moveable inductors,
the inductors in two parts surrounding the armature or the two part armature.
surrounding a double crown of inductors; whatever be the voltage, power,.
frequency, the number of poles and the method of exciting either with a continuous
current or commutated current produced by the machine itself or separately
excited.
5. The combination of any one of the forms of disc armature described and.
shown or of the form of ring disc described and shown with any one of the forms
of inductors described and shown for the construction of a simple or polyphase
alternating current generator or motor with rotating iron disc, the two inductor and
armature electric circuits remaining stationary and being directly connected with.
the outer circuit without intermediary of rings or moveable rubbers.
6. The combination of several of the types of winding described and shown the
one with the other upon the armature system or the inductor system or the two.
systems at a time or the combination of one or several of these windings with a
continuous current winding.
7. The arrangements above described and shown in the annexed drawings.
ד
11004
SYDNEY PITT..