IMPROVEMENTS IN MAGNETO-ELECTRIC AND ELECTRO-MAGNETIC MACHINES
Year: 1878

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
MAGNETO-ELECTRIC AND ELECTRO-MAGNETIC MACHINES." A communication
from abroad by Auguste de Méritens, of Paris, in the Republic of France,
Civil Engineer.
Sealed the 31st January 1879, and dated the 17th September 1878.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 17th September 1878.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. " IMPROVEMENTS IN MAGNETO-ELECTRIC AND ELECTRO-MAGNETIC
MACHINES." A communication from abroad by Auguste de Méritens, of Paris, in
the Republic of France, Civil Engineer.
This Invention relates to the construction of magneto-electric and electro-magnetic
machines based upon the following novel principle, viz. :-
Let it be assumed that a horizontal coil is employed composed of copper wire
insulated by silk, cotton, india-rubber, or other suitable material, with a core of soft-
iron placed in the centre of the coil, and that there is arranged in relation to the
said coil a permanent magnet, one of the poles of which is caused to travel along a
line parallel to the longitudinal axis of the coil and in close proximity to its.
periphery, and commencing and terminating at points beyond the extremities or
poles of the coil.
This motion will have the effect of producing in the coil until the magnet reaches
the commencement of the same an inverse current of induction with relation to the
currents of the end of the magnet.
While the magnet is traversing the length of the coil the current induced is direct
with relation to the end of the magnet; it is not instantaneous and goes on increasing
in power.

page_text: From the end of the coil to the terminal point of the stroke of the magnet the
induced current becomes again inverse with relation to the pole of the magnet.
During the entire transit therefore three induced currents are obtained, two being
inverse, and one (in the centre) being direct. On measuring the value of each of
these currents with a galvanometer it will be found that the direct current is exactly
equal to the sum of the two others.
The machine next herein-after described is constructed upon the foregoing prin-
ciple. A number of cores of soft iron (say four) are employed, which are curved so
as to form four segments of a circle with spreading poles, one at each end of each
segment, the whole constituting a ring when joined together by the said poles.
Each pole of one segment is separated from the adjacent pole of the neighbouring
segment by a blade of copper or ivory. Each iron core is covered with conducting
wire between its two spreading ends.
For the purpose of facilitating the magnetisation and demagnetisation the cores
are composed of blades of thin sheet iron placed one over the other, and rivetted
together in suitable numbers to form a ring of the required width.
The ring is keyed upon a central shaft, and is capable of rotating with it, so as
to pass before the alternated poles of permanent magnets or of electro-magnets.
In the operation of the apparatus a current, direct with relation to the inductor,
will be produced in the coil in proportion as a polar extremity approaches the said
inductor. A pole of the same denomination as the inductor is developed, and
increases at the polar extremity of a coil so long as they are not opposite each
other.
By re-action a pole of an opposite denomination is developed and increases
simultaneously through the diamagnetic partition between two segments. An
induced current is thus produced in the next coil inverse with relation to one pole,
but direct with relation to another pole of the inductors, and this alteration is
continued during the revolution of the ring.
Each of the poles of the magnets acts upon three coils at once by double induction.
Each coil changes its denomination on coming opposite a fresh pole.
The machine forming the subect of this Invention thus differs from machines having
a similar object in the simultaneous utilization of the currents of magnetisation and
of demagnetisation, the currents derived from reversal of the poles and the currents
resulting from the re-action of a first induction through diamagnetic partitions.
It thus combines every description of induction simultaneously. The number of
inducted coils or of inducting magnets may be reduced or increased according to
circumstances; for example, machines may be constructed with 8 inducting magnets
and 16 coils in the following manner:-
The coils are carried upon the circumference of a brass wheel and form a complete
ring.
The stationary magnets supported by two brass discs are symmetrically arranged
round the circumference of the ring in such a manner that the intervals between
them are equal to the solid portions.
The currents are collected by means of two insulated rubbers upon the shaft of the
machine.
The foregoing details relate to magneto-electric machines. Dynamo-electric
machines supplying an alternate current for lighting require an exciting machine
with a continuous current.
As an example of the application of the Invention to this purpose a magneto-
electric machine, with four inducting magnets and eight coils is employed, connected
by means of a sleeve to another machine, in which the inducting magnets turn, and
the coils in which the current is induced are stationary. The inducting magnets
consist of four straight electro-magnets, with cores composed of fine iron wire, as in
the case of Ruhmkorf coils. The coils in which the current is induced consist of
two rings constructed in accordance with this Invention. In lieu of being acted on
by the magnets at their periphery, as in the arrangement herein-before described,

page_text: they are acted on at their flat surfaces. The two rings are secured to two brass
bearings bolted to the base plate. The inducting magnets are carried on two brass
wheels keyed upon the shaft, and rotate between the two rings, which are fixed at a
very short distance from their poles.
The two machines being thus mounted upon the same shaft, the following results
will be obtained by their motion :-
The magneto-electric machine produces an alternate current in its ring, which
flows along a passage provided in the centre of the shaft to the straight electro-
magnets forming the inducting agents of the second machine, the current produced
in the rings of the second machine being a continuous current.
As the inducting magnets are supplied with an alternate current, when " north"
reaches a fresh coil, it changes its denomination itself and becomes "south." The.
coil will therefore continue to be traversed by a direct current with relation to
"south" (that is to say), it will not change its direction. The same may be said of
all the other coils, and the current being conducted to two binding screws placed
upon one of the stationary rings, a machine will be obtained producing continuous
currents without a commutator, without a collector, and even without a rubber of
any description.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
14th March 1879.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN MAGNETO-ELECTRO AND ELECTRO-MAGNETIC
MACHINES." A communication from abroad by Auguste de Méritens, of Paris, in
the Republic of France, Civil Engineer.
The said Invention relates to the construction of magneto-electric and electro-
magnetic machines based upon a novel principle, and to an improved method of
converting an alternate current into a continuous current.
And in order that the said Invention may be fully understood, I shall now proceed
more particularly to describe the same, and for that purpose shall refer to the several
Figures on the annexed Sheet of Drawings, the same letters of reference indicating
corresponding parts in all the Figures.
Figures 1 and 1 are diagrams illustrating the principle of the Invention.
Figure 2 is a side sectional elevation; Figure 3, a corresponding plan; Figure 4,
à corresponding end elevation, partly in section; and Figure 5, details of a magneto-
electric machine for producing alternate currents according to the said Invention.
Figure 6, represents a side elevation of a machine for producing continuous
currents; Figure 7 is a plan; and Figures 8 and 9 end elevations, both corre-
sponding to Figure 6; and Figures 10, 11, and 12 are details of the same.
The principle of this apparatus, which will be understood on referring to Figure 1,
is based on the employment of a coil K composed of copper wire insulated by silk,
cotton, india-rubber, or other suitable material, with a core a of soft iron placed in
the centre of the coil K, in combination with a permanent magnet L, one of the
poles of which (the pole N for example), is caused to travel from a point X to a
point Y.
As the magnet moves from X to the commencement of the coil K at A, it will
have the effect of producing in the coil K an inverse current of induction with
relation to the currents of the end N of the magnet L. While the magnet is moving
opposite the coil from its commencement at A to its termination at B, the current
induced in the coil is direct with relation to the end N of the magnet. It is not
instantaneous and goes on increasing in power from A to B. While the magnet is
moving from B to Y the induced current in the coil K becomes again inverse with
relation to N, consequently three induced currents are obtained during the transit
of the magnet X to Y, two being reverse and one (in the centre being direct. On
measuring the value of each of these currents with a galvanometer, it will be found
that the direct current is exactly equal to the sum of the two others.
Assuming that a number of such coils are employed as shown in Figure 1º, in
which K, K¹, K², K³, are the coils having cores a of soft iron with spreading
poles A, B, C, D, E, F, G, H, and curved so as to form four segments of a circle, the
whole will form a ring when the cores are joined together by their poles.
Each pole of one segment is separated from the adjacent pole of the neighbouring
segment by a diainagnetic partition c, consisting of a thin piece of copper, ivory, or
other suitable material, say about of an inch in thickness. Each iron core is
covered with conducting wire between its two spreading ends, as shown at A.
For the purpose of facilitating the magnetisation and demagnetisation the cores
are composed of blades of sheet iron, say about 16 of an inch in thickness, placed
one over the other and rivetted together in suitable numbers to form when the cores
are united together a ring of the required width.
This ring is keyed upon a central shaft O, and is capable of rotating with it so
as to pass before the alternated poles N, S, N, S, of permanent magnets or of electro-
magnets,

page_text: When the parts are situate with relation to each other in the position shown in
Figure 1a, and the coils are caused to move in the direction of the arrow, it will be
found that a current direct with relation to the inductor N will be produced in the
coil K from A to B in proportion as A approaches N, and a pole of the same
denomination as N is developed and increases at A so long as they are not opposite
each other.
By re-action a pole of an opposite denomination to N is developed and increases
simultaneously through the diamagnetic partition c between A and H, and an
induced current is thus produced in the next coil H, G, inverse with relation to N,
but direct with relation to S, and consequently similar to the current, which is
produced simultaneously in the coil H, G, by its transit before S. A similar effect
is produced on each of the coils of the ring in turn. Eeach of the poles of the
magnets acts upon three coils at once by double induction, and each coil changes its
denomination on coming opposite a fresh pole.
The magneto-electric or dynamo-electric machines constructed according to many
of the well-known existing systems derive their electricity exclusively from the
magnetisation and demagnetisation of the soft iron cores in the coils, in which the
electricity is induced. In the system known as Gramme's the current is derived
exclusively from the continuous and successive reversal of the polarities produced in
the annular core of a series of coils.
The machine forming the subject of the present Invention, on the contrary,
utilizes simultaneously the currents of magnetisation and demagnetisation, the
currents derived from reversal of the poles and the currents resulting from the
re-action of a first induction through diamagnetic partitions, and thus utilizes every
description of induction simultaneously. The number of inducted coils or of
inducting magnets may be reduced or increased according to circumstances, the
number of four shown in Figure 1ª to demonstrate the theory being in no way
essential.
I have shewn in Figures 2, 3, 4, and 5, as an example of the mode of practically
carrying out the said Invention, a machine constructed with eight inducting magnets
marked L, and sixteen coils marked K. These coils are separated by diamagnetic
partitions, as described with reference to Figure 1ª, and are arranged upon the
periphery of a brass wheel R, so as to form a complete ring, as shown more clearly
in Figure 4. The wheel R is fast upon a shaft O, rotating in bearings P, supported
on a suitable stand Q, and provided with pulleys o for receiving motion from any
suitable prime mover.
.
The magnets L are stationary, and are supported by two brass rings d fixed to
the stand Q, being symmetrically arranged round the circumference of the ring
formed by the coils in such a manner that the intervals between them are equal to
the solid portions.
When the shaft is in rotation the coils K composing the ring will be caused to
move in presence of the magnets L, and a series of currents will be produced in the
said coils K, as described with reference to Figure 1ª, which are collected by means
of two insulated rubbers f upon the shaft O.
The foregoing description relates to magneto-electric machines. Dynamo-electric
machines supplying an alternate current for lighting require an exciting machine
with a continuous current, and in order to enable the Invention to be applied to
this purpose the apparatus may be constructed according to the arrangement shewn
in Figures 6, 7, 8, and 9, in which a magneto-electric machine M, with say four
inducting magnets L and eight coils K (shown detached in Figure 11) is employed,
the shaft O of such machine being connected by means of a sleeve or coupling at w
to a shaft O¹ of a machine N, in which the inducting magnets rotate, and the coils
in which the current is induced are stationary. The inducting magnets in the
machine N consist of eight straight electro-magnets L', shown in section in Figures 9
and 10, having cores a¹, which are formed of fine iron wire, as in the case of Ruhmkorf
coils. The current is induced in coils K¹, forming two rings constructed in accord-
ance with this Invention (and shown most clearly in Figure 12), but in lieu of being

page_text: acted on by the magnets at the periphery of the rings, as in the arrangement herein-
before described, they are acted on at their sides. The two rings are secured to two
brass supports bolted to the base plate of the machine N. The inducting magnets L'
are carried on two brass wheels T, Figure 10, keyed upon the shaft O¹, and relate
between the two rings, which are fixed at a very short distance from their poles.
The shafts of the two machines being connected as herein-before described, the
following results will be obtained by their motion :—
The magneto-electric machine M produces an alternate current in its ring of coils,
which flows along a passage provided in the centre of the shaft to the straight
electro-magnets L₁ forming the induting agents of the machine N.
By referring to Figure 1ª it may readily be perceived that the current produced
in the rings of the machine N will be a continuous current. If N turned in presence
of A, B, (Figure 1a), it would produce a direct current in this coil (with relation
to N); at the same time S would produce a direct current in C, D, with relation to
itself (S). When N reaches C and travels from C to D, this coil charges its direc-
tion and ceases to be traversed by a direct current with relation to S, but will be
traversed by a current direct with relation to N.
In the case in question, as the inducting magnets are supplied with an alternate
current when N reaches C, it changes its denomination itself and becomes S. The
coil C, D, will therefore continue to be traversed by a direct current with relation
to S, that is to say, it will not change its direction. The same may be said of all
the other coils, and the current being conducted to two binding screws placed upon
one of the stationary rings, a machine will be obtained producing continuous currents
without a commutator, without a collector, and even without a rubber of any
description.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or may be used or carried into effect, I
would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,―
First. The system or mode of generating or inducing electric or magnetic currents
by the utilization simultaneously of the currents of magnetisation and demagneti-
sation, the currents of polar inversion, and the currents resulting from a primary
induction through diamagnetis partitions, substantially as herein-before described.
Secondly. Constructing the cores of the coils of blades of sheet iron, secured
together substantially as herein-before described.
Thirdly. The peculiar construction and arrangement of combined machine, by
means of which a continuous current is produced without the aid of a commutator
or collector, substantially as herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this my Speci-
fication set my hand and seal, this Fourteenth day of March, One thousand
eight hundred and seventy-nine.