Improvements in Electro-motors.
Year: 1890

page_text: Date of Application, 23rd Oct., 1890-Accepted, 6th Dec., 1890
COMPLETE SPECIFICATION.
Improvements in Electro-motors.
I RANKIN KENNEDY Electrician 10 India Street Kilmarnock N.B. 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 for its object improvements in the method of and in apparatus
for obtaining motive power from an alternating current of electricity. One
alternating current being applied to energise the magnets and primary circuits of said
motors said current being divided into branches.
According to my invention this new motor consists of two parts. Firstly, a motor
of any of the well known types of continuous current motors commonly in use having
a luminated field magnet and the commutator removed leaving the ends of each
armature coil or section disconnected from each other and so that they may readily
be connected to sections of wire coils on the second part of my new electro motor.
This second part of my new electro motor is a converter having a primary and
secondary winding, and an almost perfectly closed magnetic circuit luminated
throughout. That part of the magnetic circuit carrying the primary winding is fixed
and of the form of a dynamo field magnet, and that part of the magnetic circuit
carrying the secondary winding is mounted on the same shaft with the armature of
the motor part, and the secondary winding is in as many sections as there are
sections in the motor armature coils, the sections of the one being connected to
corresponding sections of the other as hereinafter described.
The secondary coils are so wound in or on that portion of the magnetic circuit,
which rotates and carries them round: that there is no induction due to the
movement or rotation, but that there is a maximum of induction due to the alternating
primary current.
And in practice the construction is made so that this second part of the motor
inductively acts equivalently to a stationary induction converter. The rotation of the
secondary portion of the converter is for the purpose of reversing the direction of
flow of the secondary currents in each section successively twice in every revolution
and thus at any instant the currents circulating in the two halves of the armature
coils are in opposite directions the same as in continuous current motors.
The secondary coils are wound in sections, each enclosing a projecting part of
the core which is luminated, and of either ring drum or disc form, and is embraced
by two or more poles of the primary magnet.
In order that others skilled in the art may clearly understand the nature of my
said invention, I have hereunto appended a sheet of drawings.
Fig. 1 is an end view shewing the field magnet and armature of motor.
Fig. 2 is an elevation of the motor showing the two magnets, the shaft and
bearings.
Fig. 3 is an end view showing the luminated magnet acting as the primary
circuit, and the luminated drum with projecting teeth, with the secondary coils
wound thereon.
Fig. 4 is an elevation showing the ring armature of the motor, and the secondary
magnetic circuit of the converter both on the same shaft, and the sections of the one
connected to the sections of the other.
Fig. 5 shows an edge and face view of the form of a disc core for the secondary
part of the converter with two luminated primary magnets applied to it.
Fig. 6 shows an edge view of a disc armature for motor part, wound obliquely and
suitable for a multipolar field. In this form of construction there is no iron core in
the armature of the motor.
Referring to Figures 1, 2, and 3 the field magnet F is made up of soft sheet iron

page_text: stampings secured together: it is wound with two exciting coils, energised by an
alternating current whose phase is adjusted to produce a magnetic flow consonant
with the flow of alternating currents in the armature coils. The armature A is made
of soft iron wires, and wound with coils of insulated wires forming the well known
Gramme Ring Armature-each armature section S. S. S. is coupled to one of the
secondary coils b. b. b. on the moveable secondary C. C. C. magnetic circuit. The
primary magnet M is made of sheet iron stampings and energised by primary
coils connected to a source of alternating currents. The currents induced in
the secondary coils are entirely due to the pulsations of the primary current, and
not in any way to their motion; a secondary coil being carried past the poles from d
to e or from ¹ to e' does not cut magnetic lines of flow in the manner necessary
for the induction of currents by motion in a magnetic field, but they are subjected
to the full inductive action of the pulsatory primary current, and its resultant
pulsatory magnetic flow, and the direction of the secondary currents at any instant
through all the coils on the one side of the dividing line J. K. is in one direction at
any instant while on the other side at the same instant they are in the opposite
direction, and this same distribution of current attains in the armature having its
coils connected one to each secondary coil, the currents in each half being at same
instant in opposite directions they produce the same effects as are obtained in
a continuous current motor armature.
Referring to Fig. 4, A is the motor armature with sections S. S. S. coupled to
secondary coils b. b. b. the secondary coils being wound on a drum having projecting
teeth enclosed by each coil, this drum being thoroughly Inminated.
Referring to Fig. 5, the disc secondary magnetic circuit N has projections carrying
the secondary coils b. b. b. on both faces, and the disc is placed between two
primary magnets M M with the poles arranged as shown, and forming segments
wide enough so that each pair of poles cover nearly one half of the projections, the
one half having a north pole on the right hand, and a south on the left hand, the
other having a south pole on the right hand and a north pole on the left hand side.
Referring to Fig. 6 a disc armature wound obliquely and constructed as described
in Ayrton and Berry's British Patent Specification No. 3036, 27th June 1882 with,
luminated field magnets, N. S. N. S. represents two of the field magnets poles four
pair being applied to the armature and four pair to the converter, the coils of the
armature are wound obliquely. G is a section through the armature and two poles.
The principle of my invention may be applied in many ways, of which those herein
shown are chosen for simplicity of explanation.
Fig. 7 shows a common form of magnet which may be used instead of the single
horse shoe form it is built up of sheet iron stampings of the form shown R placed
one up as shown and one inverted alternately to form the proper width of pole.
These new motors are energised by a branch of the main alternating current
connected to the coils on the primary magnet and by another branch connected to
the coils on the field magnet and the phases may be slightly adjusted by an
impedance coil in either circuit.
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
1st. In an electromotor operated by alternating current the combination of an
electromotor with an induction converter having a portion of its magnetic circuit
carrying the secondary windings fixed on a shaft and rotating with the armature
of the electromotor having coils in sections each connected to a section of the
secondary coils of the converter as and for the purpose substantially' as herein
described.
2nd. In an electromotor operated by alternating currents the combination of a
rotating portion of the magnetic circuit of an induction converter carrying secondary
coils with a primary magnet fixed and having wide polar faces each embracing
nearly one half of the secondary coils as and for the purpose substantially as herein
described..

page_text: 3rd. In an alternating current electromotor, the combination of an electromotor
having an armature wound with many sections, and each section connected to a
section of the secondary winding of an induction converter as herein described the
sections on one half of the armature energised by currents at any instant all in the
same direction, while at the same instant the other half of the armature sections are
energised all in the same direction, but oppositely to those of the first half, the
direction of flow being reversed twice in each revolution in each section successively
as and for the purpose as herein set forth.
4th. The method of obtaining motive power from alternating currents of electrical
energy by means of a converter having the secondary part of its magnetic circuit
carrying the secondary coils free to move and rotate with a motor armature on same
shaft, the coils of the armature being connected to the coils of the secondary of the
converter, combined with luminated primary and field magnets substantially as
herein described.
Dated this Twenty-second day of October 1890

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