Improvements in Dynamo Electric Generators and Motors
Year: 1894

page_text: Date of Application, 28th Dec., 1894
Complete Specification Left, 30th Sept, 1895-Accepted, 28th Dec., 1890
PROVISIONAL SPECIFICATION.
Improvements in Dynamo Electric Generators and Motors
I, LLEWELYN BIRCHALL ATKINSON, of 3 Whitehall Place, Westminster,
S.W., Civil Engineer, do hereby declare the nature of this invention to be as
follows.-
This invention relates to improvements in dynamo electric generators and
motors and has for its object. the provision of means whereby the amature of such
machines may be the stationary part whilst the field magnets, on which the
magnetising coil may be but is not necessarily wound, revolves, for the purpose of
educing the danger of breakdown of the armature and its coils and for the
purpose of allowing the armature coils to be coupled in series or parallel to valy
its electro motive force Dynamo electric generators and motors have been
Constructed in which the armature is fixed and the field magnets revolve, but in
them the armature and commutator are substantially of the usual type and the
brushes revolve thus preventing adjustment of the same when the machine is in
motion, this difficulty is got over by the picsent invention
In my improved type of dynamo machine or motor the commutator connected
to the arinature having as many sections as the matine has coils in its winding is
replaced by a series of brushes in number equal to the number of coils in the
aim iture; and the brushes usually applied to the commutator being equal in
number to the number of poles surrounding the amature are replaced by revolving
contact plates or blocks, coming successively in contact with the brushes before
mentioned as the magnet evolves, the connection betw con these contact plates
and the circuit is maintained by slip rings in any of the usual methods. To avoid
the use of a great number of bushes, I apply commutator coils, or reverse coils
or reversing field poles in addition to the mam field poles thus avoiding spiking
or great variation in position of the brushes with varying loads. The field magnet
may be of various types, either having the coils fixed upon it and evolving with
it, or by carrying pait of the magnetic circuit parallel to the axis of revolution,
the coil surrounding the magnet may be fixed, the magnet only revolving, the
winding may be shunt, series, or compound, as the case may be, to suit the
purpose for which the mache is required In certain cases the winding may be
dispensed with altogether and the magnetic encuit excited by the coils on the
armature, by giving a suitable lead to the brushes, or a separate winding may be
provided on the armature with its own brushes, and revolving contact plates,
situated in a 2 pole machine 90° or thereabouts from the main armature winding,
for the purpose of magnetizing the revolving magnet The brushes may be
connected to the armature coils by flexible connections for the purpose of enabling
them to be fixed in a carrier and rocked for the purpose of putting them in the
best position as to sparking, or to vary the magnetizing effect of the armature
on the field magnet, or to vary the E.M.F. of the armature.
Dated this 28th day of December 1894.
FELL & WILDING,
1 Queen Victoria Street, London, E.C., Agents for the Applicant.

page_text: Improvements in Dynamo Electric Generators and Motors.
I, LLEWELYN BIRCHALL ATKINSON, of 3 Whitehall Place, Westminster,
S.W. Civil Engineer, 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.—
This invention relates to improvements in dynamo electric generators and motora
and has for its object the provision of means whereby the armature of such
machines may be the stationary part whilst the field magnets, on which the
magnetising coil may be but is not necessarily wound, revolves, for the purpose of
reducing the danger of breakdown of the ni mature and its coils and for the purpose
of allowing the ai mature coils to be coupled in series or parallel to vary its electio
motive force.
Dynamo electric generators and motors have been constructed in which the
amature is fixed and the field magnets revolve, but in them the armature and
commutators are substantially of the usual type and the bushes revolve thus
preventing adjustment of the same when the machine is in motion; this difficulty is
got over by the present invention.
In my improved type of dynamo machine or motor, the commutator which m
ordinary types is connected to the armature having as many sections as the
armature bas coils in its winding, is replaced by a series of brushes in number
equal to the number of coils in the armature, and the brushes usually applied to
the commutalo being equal in number to the number of poles surrounding the
atmature ato replaced by evolving consact plates or blocks, coming successively
in contact with the brushes before mentioned as the magnet revolves, the
connection between these contact plates and the circuit is maintained by slip rings
many of the usual methods. To avoid the use of a great number of coils and
brushes, apply commutator coils, or reverser coils or reversing field poles in
addition to the main field poles thus avoiding sparking or great variation in
position of the brushes with varying loads. The field magnet may be of various
types, either having the coils bxed upon it and revolving with it, or by carrying
part of the magnetic cucuit parallel to the axis of revolution, the coil surrounding
the magnet may be fixed, the magnet ouly revolving, the winding may be shunt,
series, or compound, as the case may be, to suit the purpose for which the
machine equned. In certain cases the winding may be dispensed with
altogether and the magnetic circuit excited by the coils on the armature, by giving
a suitable lead to the brushes. The brushes may be connected to the armature
coils by flexible connections for the purpose of enabling them to be fixed in a
cale and 1ocked for the purpose of putting them in the best position as to
sparking, or to vary the magnetizing effect of the armature on the field magnet, or
to vary the E.M.F. of the aimature.
And in order that my invention may be the better understood I now proceed to
describe it in relation to the diawings hereunto annexed reference being had to
the letters and figues marked thereon.
Figure ebows diagrammatically a dynamo electric machine constructed in
accordance with my invention. A is the fixed armature ring built of laminated
ion and wound with coils, in this case shewn wound after the manner of a gramme
ring and connected together, wires numbered 1 to 12 being brought from the
Intercoil connections.
Bis the revolving magnet, magnetized as shown by the coil a b and having in
this bgure subsidiary pole pieces at right angles to the main poles magnetized by
coil o d.

page_text: Figure 1 shows the airangement of brushes, which are connected to the
points 1-12 1espectively, and press on a cylinder carrying two contact plates рg,
the said plates being so arranged that in the revolution of the cylinder they make
contact in turn with brushes 1 to 12 there being a period during which adjacent
brushes are connected through the plate, for the purpose of reversing the current
in the coil, between the brushes thus connected, in the manner well understood by
those versed in the art.
The plate p is connected to the slip ring and brush y.
The plate is in this case connected through the coils cd to the slip ring and
brush, and y being connected to the external circuit.
The ends ab of the main maguetising coil are also connected to p q, then furnishing
a shunt winding.
When the magnet is to have in addition a series winding for the purpose of
making the winding a compound winding the series coil of the main magnet will be
connected in series with the coil cd between plate g and ring .
In place of the current in the coils being reversed by the action of the series
wound subsidiary magnets shewn in Figure 1 the same result may be achieved, by
providing as shown in Figure 2 au independent fixed ring C arranged parallel to A
but shown for convenience laiger in diameter on which are wound 10versing coils,
such coils being connected between the intercoil points and the brushes and so
placed that an independent inagnet M, will act upon that coil which is connected to
one of the intercoil points leading to the armature coil to which the current is to be
eversed. The magnet M 18 excited by a coil in series with the external circuit as
are the subsidiary magnets in Figuro 1.
Figure 3 shews another method of reversing the current in the coils, but in this
method some adjustment of the bushes becomes uecessary, as the load vanes, since
the E.M.F. applied to the coil to reverse the current is not proportional to the
current as in the case of Figures 1 and 2. In this airaugement commutating coils
are provided, wound on the same ring as the main armature coils, but displaced i
position so that of the two coils connected to the intercoil points, leading to the
coil in which the current is to be reversed, one is under the action of the pole
which is strengthened by the atmature cuirent, the other is not under either pole.
Various methods of applying such commutating coils are known to those acquainted
with the art.
In the arrangement so far descubed, the magnetising coil revolves with the
magnet, but in the case of series wound dynamos, that is dynamos in which the
excitation is proportional to the current in the external circuit the exciting coil on
the main magnet may be dispensed with, and the revolving magnet magnetized by
the armature coils, by giving the brushes (if a generator) a forward lead
(corresponding to a backward lead of the brushes of an ordinary machine) or in a
motor by giving the brushes a backward lend. This arrangement is specially
adapted for use with commutating coils as in Figure 3.
The magnet as shewn in Figures 1, 2, 3, 18 of the form shewn in Figure 4 where
the coil is shewn lying in a plane parallel to the axis. But by constructing the
magnet of the form shown in Figure 5, the coil may be wound in a plane at right
angles to the axis and covered by the polar expansions shewn.
A modified construction is shewn in Figure 6 allowing the exciting coil to be
fixed so that only the iron revolves.
Figure 7 shows the construction of the framework for such a machine in
which N N are ings of laminated iron, carrying the coils, F is a framework of
solid magnetic material, the exciting coil X is shewn between the coils within
the framework and surrounding the axis of the magnet which bas polar
extensions.
In these cases where the reversal 18 effected by subsidiary magnets or reversing
coils the machines will be built in two halves similar to one another in general
construction but not necessarily in size, one half containing the main magnet and
armature coils, the other half containing the subsidiary maguct and reversing coils.

page_text: Where the reversal is effected by commutating coils, those coils will be wound on
the same cores as in Figure 3.
"1
The armature being fixed the coils may be wound in sections, and these sections
may be coupled in series or parallel, by any of the well known devices for securing
this object, for the purpose of varying the E.M.F. and current which the armature
will give
This 16 specially applicable to motors for locomotive purposes.
Though the descriptions herein refers to bi-polar machines wound with "grammie
windings, inultipolar machines or dium windinge, and either plain cores, or notched,
or hole wound cores may be used in manner well understood, and further although
the description and figures show the armature arranged externally to the revolving
magnet, it will be understood that the stationary armature may be inside the
revolving magnet, or he between the pole faces of the magnet, one being on each
side of it.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I wish it to be understood
that do not claim the use of a revolving magnet and stationary armature, either
with fixed or revolving brushes, but I declare that what I do claim is :-
1st. In a continuous current generator or noto in combination, a fixed armaturo
a revolving magnetic field, aubsidiary revolving magnets adapted to reverse the
cument in the armature coils, stationai y brushes, connected to the armature coils,
revolving contact makers and ship rings adapted to make connection with the
stationary bushes and the external circuit, substantially as described.
2nd. In a continuous curient generator or notor in combination, a fixed armature,
a revolving magnetic field, reversing coils and reversing poles adapted to reverse
the current in the armature coils, stationary brushes connected through the said
reversing coils to the armature coils and revolving contact makers and slip rings
adapted to be in contact with an external cncunt, substantially as described.
3id. In a continuous current generator or motor, in combination, a fixed amature,
a revolving magnetic field, commutating coils adapted to reverse the current in the
armature coils, stationary brushes connected through commutating coils to the
armature, evolving contact makers adapted with means for connection to an
external circuit, substantially as described.
4th. The construction and arrangement of a generator or motor of the form
claimed in either Claim 1, 2, or 3 having a revolving field magnet wound with a
coil about its axis, substantially as described and illustrated in Figure 5 of the
accompanying drawings.
5th. The construction and arrangement of a generator or motor of the form
claimed in either Claim 1, 2 or 3, having a revolving field magnet as shown in
Figure 6 with a stationary coil wound about the axis of the said field magnet,
duplicate arinature cores and a containing casing, substantially as described and
illustrated in Fig. 7 of the accompanying drawings.
6th. The general construction and airaugement of dynamo electric generators
and motors substantially as described and illustrated in Figures 1 to 7 of the
accompanying drawings.
Dated this 28th day of September 1895.
FELL & WILDING,
1 Queen Victoria Street, London, E.C., Agents for the Applicant.