An Improved Alternating Electric Current Motor.
Year: 1891

page_text: Date of Application, 12th Aug., 1891-Accepted, 10th Oct., 1891
COMPLETE SPECIFICATION.
An Improved Alternating Electric Current Motor.
We, WILLIAM BLANCH BRAIN, of No. 24 Villiers Street, Elsternwick near
Melbourne in the Colony of Victoria, Mining Engineer, and ARTHUR JAMES
ARNOT, of the Town Hall, Melbourne aforesaid, Electrical 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 has been devised for the purpose of providing a simple and
efficient motor whereby alternating electric currents may be utilised for motive
purposes.
Our invention embodies two principles one being that of the alternating current
transformer, and the other that of the Siemens' electric dynamometer.
In the first of these two apparatus the primary current is used for the purpose of
inducing another current, and it accomplishes this result. by reason of the well-
known inductive effect which the current passing along a wire in a given direction
has upon another wire arranged parallel and in close proximity to it, especially
when iron is in proximity to it or is used as a core.
The principle of the second apparatus is based upon the well-known electrical
law that currents flowing through two parallel wires in opposite directions will
cause said wires to repel and in the same direction attract each other.
In carrying our invention into practice in its simplest form we provide a coil of
wire, or compound solenoid wound spirally in the form of an annulus, and we
conduct the primary or main current around the two halves of said spirally wound
annular coil, or compound solenoid, in opposite directions, that/is, so that if a.
magnetic core were included in said coil or solenoid such current would tend to
form double north poles at, say the top, and double south poles at the bottom. In
close proximity to this spirally wound annular coil, or compound solenoid, we
arrange another similar coil or solenoid whose individual convolutions are so'
arranged as that at any given moment they will be approximately parallel to the
adjacent convolutions of the first-mentioned spirally wound annular coil. This said
second coil or solenoid is mounted upon a spindle in such a manner as that it can
revolve freely, whilst the first one is a fixture. A commutator is connected with
this moveable spirally-wound annular coil (or armature, as we shall hereinafter
describe it) in order that its different sections may be automatically included in
either the right or the left-hand half as it revolves so as to ensure the two halves
of the armature, or revolving spirally-wound annular coil or compound solenoid,
and the field or stationary coil being always in harmony with each other,
i.e. allowing the attractive and repelling forces to act simultaneously so as to rotate
the armature in the same direction.
In this primary or simplest form of our alternating electric current motor,
the two brushes of the commutator may be short-circuited, the result being (as
the current passes round the opposite sides of the fixed coil or field) to induce
corresponding currents in the two halves of said armature in the opposite
direction, on the same principle that governs the operation of an alternating
current transformer. These two currents, flowing in opposite directions, will
cause the parallel wires through which they flow to alternately repel and attract
each other owing to the well-known law which governs the operation of the
Siemens' dynamometer, and the result of these combined operations will be to
cause the moveable coil or armature of our motor to revolve.
In order to increase the efficiency of our motor we prefer to provide a pair of
fields or fixed coils, one on either side of the revolving coil or armature, because

page_text: by that means we utilise the inductive effect of the current on both sides of said
armature instead of only one. Again, in order to still further increase the efficiency
of the motor, a series of coils may be arranged side by side, thus enabling a
correspondingly greater proportion of their total inductive area to be utilised.
For instance, if we employ seven coils, then five of their sides will be utilised,
that is, ths of the whole area will be in operation, and similarly if a larger
number be used a correspondingly greater proportion of area will be in operation.
By inserting iron cores either in the fixed or revolving, or in both the fixed
and revolving spirally-wound annular coils, we still further increase the efficiency
of the machine, because by that means we utilise the magnetic effect of such iron
cores in addition to the inductive effect of the wires surrounding them. By
preference we provide the revolving coil or armature with a magnetic core, and
construct the other coils or fields without magnetic cores.
The machine may be coupled up in many different ways, as will be well under-
stood by electricians. For instance, it might be in series, the same motive current
being conducted first through one field or fixed spirally-wound annular coil,
passing in opposite directions around each half thereof, then through the moveable
coil, passing in opposite directions through each of its halves, then through the
other field or fixed spirally-wound annular coil, passing in similar directions round
its halves so as to correspond with the halves of the first fixed spirally-wound
annular coil or field, and so on through the whole series, if more than three coils
are employed. Or the fields of the armature or armatures (if more than one be
employed) might be coupled up in parallel so that the current would divide, and
only a certain proportion of it would travel through each coil instead of, as in the
series arrangement, the whole current passing through all the coils. Or the
armature might be in shunt to the fields, or it might be supplied with current from
an independent source, as will be well understood, it being merely essential
according to this invention that the alternating current is caused to flow in opposite
directions around the halves of a stationary or a revoluble spirally-wound annular
coil adjacent to it, from which it is receding, and in the same direction as that to which
it is approaching, each convolution of each of said coils being so arranged as to be
at any given moment approximately parallel to its nearest convolution in the
adjacent coil.
.
Referring to the accompanying drawings
Fig. 1 is a diagrammatic view illustrative of the simplest form of an alternating
current motor constructed according to this invention, and shewing same coupled
up in series.
Fig. 2 is a similar view to Fig. 1, but illustrating the addition of iron cores to
both armature and field.
Fig. 3 is also another similar view, but illustrating the employment of a pair of
fields with one armature revolving between them.
Fig. 4 is an end elevation, and
Fig. 5 a side elevation of an alternating electric current motor, constructed
according to the modification of our invention illustrated in Fig. 3.
.
Fig. 6 is a vertical transverse section on line 6, 6, Fig. 5.
Referring to the simplest form of our improved alternating current motor, as
shown in Fig. 1, A represents a spirally-wound annular fixed coil or compound
solenoid, and B a spirally-wound annular revoluble coil of wire, each of which is
wound in such a manner as that the current will be caused to flow in opposite
directions round the two halves of said coils, whilst at the same time it travels in
opposite directions round the convolutions of each of the adjacent halves of said coils,
as will be well understood on reference to the diagram referred to. The effect of this
arrangement would be, as will be well understood by electricians, to form double
north poles at the top of one of said rings, and double south poles at the top of
the other ring, if a magnetic core were inserted within said coils.
It is essential in this invention that each individual convolution of the fixed
spirally-wound annular coil must at any given moment be approximately parallel

page_text: to the adjacent convolution of the revolving spirally-wound annular coil B, in order
that the current passing in one direction through the first-mentioned convolution
may act upon the current passing in the opposite direction through the second
convolution of the revolving coil B, and thus serve to repel this latter on the same
principle that governs the Siemens' electric dynamometer.
Although the arrangement illustrated in Fig. 1 is shewn coupled up in series, it
will be obvious that the fixed coil A. and the movable coil B might be in parallel
or the one might be in shunt to the other. A commutator C, secured to the
revolving coil B, enables the current to be automatically conducted to each half of
said revolving coil as required, so that the current flowing through said halves will
always be in the opposite direction to the current flowing around the corresponding
half of the fixed coil A. By this means the attracting and repelling forces of the
current will be utilised to always rotate the armature B in the same direction.
Another modification of this form of our invention consists in short-circuiting
the two brushes D, D, allowing the motive current to flow only round the fixed
coil A, and thus induce another current in the opposite direction in the revolving
coil or armature B, the effect being the same but in a much less degree to that
produced by passing the primary or motive current in opposite directions through
both the coils.
In order to increase the efficiency of the motor the two parallel spirally-wound
annular coils A, B, may be provided each with an annular iron core, preferably
made of laminated iron or soft iron wires, in order to reduce the residual inagnetism
as much as possible as well as to prevent the formation of Foucault currents.
preferred, only one of these coils need be provided with an iron core, the other coil
being constructed without.
If
If
In order to still further increase the efficiency of our motor we prefer to
construct it as shewn in Figs. 3 to 6, with a pair of fixed coils A, A, on either
side of the revolving coil or armature B, as by that means we are enabled to
utilise the lines of force radiating from each side of said revolving coil.
preferred, the numbers of such coils might be increased; for instance, we might use
seven coils, in which case ths of their area would be utilised, and similarly if a
still larger number were employed, a still greater proportion of area would be
rendered effective.
The examples given in Figs. 5 and 6 are merely intended as examples of the way
in which our improved alternating electric current motor can be constructed, it
being obvious that many different modifications and arrangements of mechanical
parts might be preferred to those shewn.
It will be obvious to all persons skilled in the science of electricity that,
with a
motor constructed as herein described, there will be no difficulty in
starting it. Neither will it be necessary to maintain it in perfect synchronism
with the dynamo machine; and, moreover, the difficulty which has hitherto
been experienced, owing to the rapidity of the changes in alternating currents
being faster than it was possible to alter the polarity of the electro-magnets, will
be obviated.
Our improved alternating current motor will work independently of the number
of changes in the direction of the current.
Seeing that as the rate of change in one coil of the motor is simultaneous in
the other coils, therefore the magnetic whirls, or lines of force, always maintain the
same relation to one another, either attraction or repulsion, and are not dependent
on the magnetic moment as is the case in some motors where you must synchronise
with the generator.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is-
First. An alternating current motor wherein the action of a current flowing
along a wire upon another current flowing along an approximately parallel and

page_text: adjacent wire, is utilised to cause the rotation of the armature of said motor,
substantially as herein described and explained, and as illustrated in our drawings.
Second. An alternating current motor consisting essentially of two spirally
wound annular coils of wire (such as A, B) one of which is fixed, whilst the other
can revolve, the whole being so constructed and arranged as that the motive current
will be caused to travel in opposite directions around the two halves of each of said
coils, a commutator and brushes being employed for inserting the different sections
of the rotating coil or armature into its proper half of the circuit, so that it will
correspond or harmonize with the adjacent half of the fixed coil or field, sub-
stantially as and for the purposes herein described and explained, and as illustrated
in Figure 1 of our drawings.
Third. An alternating current motor consisting of a pair of spirally-wound
annular coils arranged parallel to each other, the one being a fixture; and the other
free to revolve, this latter being moreover provided with a commutator and brushes
for automatically inserting its sections into the requisite circuit, combined with a
laminated iron or other magnetic core inserted within either one or both of said coils,
substantially as and for the purposes herein described and explained, and as
illustrated in Figure 2 of our drawings.
Fourth. An alternating current motor consisting of three or more spirally-
wound annular coils of wire arranged side by side, each alternate coil being a
fixture, and the others revoluble, the current being led in opposite directions around
the halves of the alternate coils, whose adjacent convolutions are approximately
parallel to each other, a commutator or commutators and brushes being employed
for automatically inserting the different sections of the revoluble annular coil or
coils in circuit with one or other of its halves so as to ensure the current flowing
through said halves in opposite directions to that flowing through the corresponding
halves of said fixed annular coils, the whole being constructed and arranged sub-
stantially as and for the purposes herein described and explained, and as illustrated
in Figures 3 to 6 of our drawings.
Fifth. An alternating current motor, consisting of three spirally-wound
annular coils of wire arranged side by side, the centre one being revoluble and the
other two being fixtures, the current being led in opposite directions around the
two halves of the alternate coils, a commutator and brushes being employed for
automatically inserting the different sections of the revoluble annular coil in circuit
with one or other of its halves, and said revoluble coil being provided with a
magnetic core, whilst the other two coils are constructed without any such core
substantially as and for the purposes specified and as illustrated in the accompanying
drawings.
Dated this Sixth day of July One thousand eight hundred and ninety-one.
WILLIAM BLANCH BRAIN.
ARTHUR JAMES ARNOT.