A DYNAMO- ELECTRIC OR MAGNETO-ELECTRIC MACHINE TO CONVERT MECHANICAL ENERGY INTO ELECTRICITY, OR TO CONVERT ELECTRICITY INTO MECHANICAL ENERGY." SP
Year: 1880

page_text: LETTERS PATENT to John Perry, Bachelor in Engineering, late Professor of
Engineering, Imperial College of Engineering, Tokio, Japan, of 14, Talgarth
Road, West Kensington, London, W., for an Invention of "A DYNAMO-
ELECTRIC OR MAGNETO-ELECTRIC MACHINE TO CONVERT MECHANICAL ENERGY
INTO ELECTRICITY, OR TO CONVERT ELECTRICITY INTO MECHANICAL ENERGY."
PROVISIONAL SPECIFICATION left by the said John Perry at the Office of
the Commissioners of Patents on the 18th March 1880.
JOHN PERRY, Bachelor in Engineering, late Professor of Engineering, Imperial
College of Engineering, Tokio, Japan, of 14, Talgarth Road, West Kensington,
London, W. "A DYNAMO-ELECTRIC OR MAGNETO-ELECTRIC MACHINE TO CONVERT
MECHANICAL ENERGY INTO ELECTRICITY, OR TO CONVERT ELECTRICITY INTO
MECHANICAL ENERGY."
All dynamo-electric or magneto-electric machines are applications of a principle
discovered by Faraday, that when a conducting circuit moves in a magnetic field
of force a current is produced in it. In the Gramme, Siemens, and other continuous-
current-machines the magnetic field is necessarily weak, because the inducing
magnets must be placed at a considerable distance apart for their lines of force to
pass mainly through the moveable conducting circuits. In all these machines this
concentration of the lines of force is materially helped by the use of soft iron in
the moveable part, but at very high speeds such soft iron can no longer help in
intensifying the magnetic field through which the conductors move. In alternating-
current machines, such as that of Wilde, a very intense field is possible, but great
loss of power occurs in making such currents continuously pass through an external
circuit in one direction. Now it is my object to get an intense field and at the
same time to have my currents continuous. I employ my machines with other
commutators than the one described below to give discontinuous currents which are
not so quickly varying as in other machines, but I mainly employ them to give
continuous currents, using a commutator of the ordinary kind, or preferably the
one described below.
My moveable conductors consist of coils of insulated wire of copper or iron, which
I usually place round a strong annular core. The core may be of any material

page_text: having the requisite strength, and usually I make it of steel or of phosphor-bronze,
but for machines in which slow speeds are employed it is made of soft iron. In
general the use of my core is to give strength and stiffness to the rotating coils,
and I consider that for high speeds that material and construction of core should
be employed which allows fewest induction currents to be formed in it. I there- 5
fore keep this core as small in section as possible consistent with the strength of
the arrangement, and in my smaller machines I altogether dispense with it, the
coils having then no internal spaces but being wedged into their proper positions
by a surrounding ring of wood and an interior disc of wood.
In the machines of Wilde and others each winding of wire is as nearly as possible 1
at right angles to the axis of rotation; in the machines of Gramme, Siemens, and
others each winding of wire is as nearly as possible in the planes containing the
axis of rotation. Each winding of wire in my machine on the rotating part makes
a decided angle with the axis of rotation, say, from 30 to 60 degrees. When a
core is used I usually divide it into two halves, as at a, b, Fig. 2. A great number 1
of thin wedge-shaped coils, like c, Figs. 2 and 3, are each wound upon a peculiarly
shaped bobbin; they are soaked in a stiffening insulating material, and when this
hardens they are removed from the bobbin, retaining their proper wedge shape;
they are then slipped upon the halves of the core, which when nearly filled with
them are bolted together at the ends, the small vacant spaces in the core being s
wound by hand or left vacant for the straps, such as a, b, d, which fasten the core
to the inside disc of wood, which is keyed to an internal shaft, such as e, f, Fig. 1.
Any method of fixing the coils so that they form a ring which may be rotated, and
so that each winding everywhere makes a certain angle with the direction of its
motion, may be adopted.
The coils are all connected so that they form one complete closed circuit. The
ends of each coil are also attached to the insulated pieces of any commutator, such
as is usually employed in such machines, but I prefer to use the following new
kind of commutator:-In well known machines the terminals of any exterior
circuit are usually metallic brushes, formed of wires or strips, which rub upon pieces
of metal attached to the ends of all the moveable coils, insulated from one another
by thin pieces of solid insulating material inserted between them. The smaller the
diameter of the cylindric rubbing surface the less power is lost in friction, and there
must therefore be much loss of electricity through the insulating material and over
its surface from one insulated piece of an ordinary commutator to the others. I
attach the ends of my coils to a number of curved rods g, h, Fig. 1, insulated from
one another by rigid insulating material, not at h, the place where the electricity
is collected, but at g, where the rods may be separated from one another by con-
siderable distances. The rods are so shaped that they are arranged at their free
ends h in a small circle, where they are only separated by thin spaces of air, and it
is here that the electricity may be collected from them by metallic contact pieces
or brushes. In this way, depending on the strength of these insulated rods, I get
superior insulation and little friction. In my larger machines where there are
many rubbing brushes I have more than one such rubbing surface, so that loss of
power through friction may be as small as possible.
I produce a magnetic field of force such that the lines of force pass nearly at
right angles to such windings of the coils as happen to be in the most intense parts
of the field, that is, these lines of force are neither in the direction of motion of the
coils, as in the Gramme machine, nor at right angles to it, as in the Wilde machine;
but they make a distinct angle with this direction of from sixty to thirty degrees.
To do this I use permanent magnets or electro-magnets, whose opposite poles are
on opposite sides of the rotating ring; not directly opposed to one another, but
shifted with respect to one another in the direction of motion of the ring, so that,
straight lines joining corresponding points of the two poles make a distinct angle,
say, from sixty to thirty degrees, with the direction of motion of the ring at that
place. Thus, suppose I have a number of N poles and the same number of S poles
acting upon one ring, N and S are placed on opposite sides of the ring, so that

page_text: their mutual lines of force pass obliquely through the ring; N, is on the same side
of the ring as S₁, but so far removed that only a few lines of force pass from one to
the other; S, is on the same side of the ring as N₁, but so far removed that only a
few lines of force pass from one to the other. Whereas there is an intense field of
oblique lines of force between N, and S. In Fig. 4 if AB is part of the rotating
coiled ring looked at edgewise, if a b, ab, are the direction of winding the magnets
N₁, S, N, S₂, would be placed as shown.
I claim as my Invention, first, the arrangement of moveable coils so that the
plane of each winding makes a certain angle with the direction of motion, whether
this motion is one of rotation, as it is in the machines which I have as yet con-
structed, or whether it is one of mere translation, or whether it is a motion
compounded of translation and rotation; second, the creation of a field of force
such that where it is most intense the lines of force are inclined to the direction of
motion of the coils, and pass nearly all at right angles through a few neighbouring
windings; third, the commutator which has been described.
When I employ electro-magnets to create my magnetic fields the current which
passes in them may be the current produced by the machine itself, or one of the
currents so produced, or part of any one of them (the brushes being connected
through an electromagnet independently of the outside circuit), or an independent
current from some exterior source.
Figures 1, 2, 3, and 5 are taken from Drawings of a machine which is being
constructed; but it is obvious that my machines may assume very different forms.
My coils might be arranged in a prismatic form, and get a reciprocating motion
parallel to the axis of the prism. Again, by the use of few or many magnets the
appearance of the machine will alter.
In the Figures ef is a shaft made to rotate; ab is a ring of phosphor-bronze or
of steel on which a great number of thin wedge-shaped coils are packed so as to
form an annular armature, whose section is shown at kk. The plane of each
winding of this armature makes an angle of forty-five degrees with the direction
of its motion when turning. The core ab is fastened to the disc of wood ii, which
is keyed to the rotating shaft, and fills up the central part of the armature. All
the wire wound on the armature forms one closed circuit; but the ends of one thin
coil and of its neighbour are also fastened to an insulated rod of copper gh, there
being as many such rods as there are of little coils in the armature; m, m', are six
electro-magnets whose cores at m are fastened through a soft-iron ring rr to the
cast iron standard 8. The ends m' are furnished with nearly square or rather
sectorial plates of soft iron, which nearly touch one side of the armature. The
ends m' are bedded in a frame of wood, which is held down to the base of the
machine by a strap of brass so that they cannot move. On the other side of the
ring there are six similar electro-magnets similarly placed with regard to one
another and the armature; but this system of magnets is moved ten degrees with
regard to the first system, and fixed in the same way as the first, see Fig. 5. Thus
the lines of magnetic force from n¹ to m' pass nearly at right angles to the windings
of the wire between them. There are six contact pieces rubbing on or near the ends
of the insulated pieces g, h. From two of these a current of electricity is taken to
excite all the electromagnets. From each of the other pairs of contact pieces
currents are taken into exterior circuits.
It is my intention-to-construct these machines with internal resistances of from
one to one-thousand ohms., those of low resistance being employed for such purposes
as electric lighting and electro-plating, and those of high resistance being employed
for telegraph purposes to replace voltaic batteries.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Perry in the Great Seal Patent Office on the 17th September
1880.
JOHN PERRY, Bachelor in Engineering, late Professor of Engineering at the
Imperial College of Engineering, Tokio, Japan, of 14, Talgarth Road, West
Kensington, London, W. "A DYNAMO ELECTRIC OR MAGNETO-ELECTRIC MACHINE
TO CONVERT MECHANICAL ENERGY INTO ELECTRICITY, OR TO CONVERT ELECTRICITY
INTO MECHANICAL ENERGY."
All dynamo-electric and magneto-electric machines are applications of a principle
discovered by Faraday, that when a closed conducting circuit moves in a magnetic
field of force a current of electricity is produced in it. In the Gramme, Siemens,
and other continuous-current machines the magnetic field is necessarily weak
because the inducing magnets must be placed at a considerable distance apart for
their lines of force to pass mainly through the moveable conducting circuits. In
all these machines this difficulty is to some extent done away with by the use of
soft iron in the moveable part; but at very high speeds, such as are usual and
necessary, the soft iron can no longer help in intensifying the magnetic field in
which the conductors move, and even at lower speeds when the soft iron is really
useful in intensifying the field of force, the rapid changes of polarity cause great
heating of the iron. In alternating-current machines, such as that of Wilde, a very
intense magnetic field is possible, but great loss of power occurs on account of the
rapidity of change in the character of the currents. Now it is my object to get a
very intense magnetic field, and at the same time to have my currents continuous.
I employ my machines, with other commutators than the one to be presently
described, to give alternating currents which are not so quickly varying as in other
machines, but I mainly employ them to give continuous currents using a commu-
tator of the ordinary kind, or preferably the one described below. My moveable
conductors consist of coils of insulated copper or iron wire, usually placed round a
strong annular core. The core may be of any material having the requisite strength,
and usually I make it of steel or phosphor-bronze, but for machines in which slow
speeds are employed it is made of soft iron. In the machines of Gramme, Siemens,
and others each winding of wire is as nearly as possible in the plane containing the
axis of rotation. In the machines of Wilde and others each winding of wire is as
nearly as possible at right angles to the axis of rotation, or its plane is parallel to
the direction of motion. Each winding of wire on the rotating part of my machine
makes a decided angle with the axis of rotation, say from twenty to seventy
degrees. In winding my ring I usually divide the core into two halves; a great
number of thin wedge-shaped coils are each wound upon a peculiarly shaped bobbin ;
they are soaked in some stiffening insulating material, and when this hardens they
are removed from the bobbin retaining the proper wedge shape; they are then
slipped upon the halves of the annular core, which, when nearly filled with them,
are screwed together at the two ends, a little of the ring having to be wound by
hand. Sometimes my coils are not wedge-shaped, and the spaces between them on
the outer part of the ring are to be filled with paper or wood. In general the use
of my core is to give strength and stiffness to the rotating coils, and I consider that
for high speeds that material and construction of core should be employed which
allows fewest induction currents to be formed in it. I therefore keep this core as
small in section as possible, consistent with the strength of the arrangement, or I
form it of a number of strips or bars insulated from one another, and in my smaller
machines I altogether dispense with it, the coils being then fixed by means of an
internal disc of wood and a surrounding ring of wood, thin plates of metal,
preferably soft iron, enclosing them at the sides. Sometimes I lay them in a
groove of nearly semi-circular section in a wooden disc, and keep them rigid by
bolting another similarly grooved disc to the first. In this case I place pieces of

page_text: iron outside the discs where the wood is thin, partly for strength and partly to
create a magnetic field. The ends of the coils of my rotating armature are soldered to
the insulated pieces of any commutator, such as is usually employed in such machines,
but I prefer to use a commutator whose pieces are insulated in the following manner:-
The terminals of any exterior circuit are usually metallic brushes formed of
wires or strips which rub upon pieces of metal attached to the ends of all the
moveable coils insulated from one another by material inserted between them.
The smaller the diameter of the cylindric rubbing surface the less power is lost in
friction, but the smaller is this diameter the greater must be the loss of electricity
through the insulating material and over its surface from one insulated piece of the
commutator to the others. I attach the ends of my coils to a number of curved
metal rods insulated from one another by rigid material, not at the place where
the electricity is collected, but at places where the rods are separated from one
another by considerable distances. The rods are much nearer together at their
free ends than at their fixed ends, and form a circular surface where the electricity
may be collected from them by brushes or friction-rollers. In this way, depending
on the stiffness of these insulated rods and on the superior insulating qualities of
air for short distances, I get good insulation and little frictional loss of power.
My brushes or friction wheels may be few or many, depending on the way in which
the coils of my armature are connected with one another, and although I generally
prefer to use as many insulated rods as there are coils I may use a smaller number.
I produce a field of magnetic force, such that the lines of force pass nearly at right
angles to such windings of the coils as happen to be in the most intense parts of
the field; that is, these lines of force are such that they are neither in the direction
of motion of the coils as in the Gramme machine nor at right angles to it as in the
Wilde machine, but they mainly make a distinct angle with this direction of from
twenty to seventy degrees. To do this I use electro-magnets or permanent
magnets whose opposite poles are on opposite sides of the rotating ring not directly
opposed to one another, but shifted with respect to one another in the direction of
motion of the ring, so that straight lines joining corresponding points on the two
poles make a distinct angle of from twenty to seventy degrees with the direction
of motion of the armature at that place. Thus, suppose I have a number of north
poles N and of south poles S acting on one ring, N, and S, are placed on opposite
sides of the ring so that their mutual lines of force pass obliquely through the
ring and nearly at right angles to the windings of the coils; N₂ is on the same
side of the ring as S, but so far removed that only a few lines of force pass from
one to the other; S, is on the same side of the ring as N₁, but so far removed that
only a few lines of force pass from one to the other, whereas there is an intense
field of oblique lines of force between N, and S. When, as is usual, I employ
electro-magnets to create my magnetic fields, the current which passes in them
may be the current produced by the machine itself, or one of the currents so
produced, or part of any one of them, or an independent current from some
exterior source. It is obvious that instead of having the magnets fixed and the
armature moveable I may use a fixed armature and moveable magnets, so that in all
that precedes when I speak of motion of the armature I really mean its motion
relatively to the magnets. The following description of one form of my Invention
is given here that my Invention may be readily understood;
but my Invention
may take other forms quite different from this in appearance through the use of a
greater or less number of fixed magnets, the use of a different kind of commutator
or method of collecting electricity from the separate coils, and again from the use
of a prismatic armature having a reciprocating motion in the direction of its axis
and in many other ways:-Fig. 1 is the sectional elevation of a machine which is
now being constructed; e f is a shaft made to rotate; a b is a ring of phosphor
bronze on which a great number of thin wedge-shaped coils are packed so as to
form an annular armature whose section is shown at k, k, Figures 1 and 3. The
plane of each winding of this armature makes an angle of 50 degrees with the
direction of motion when turning with the shaft. Three of the coils are shown

page_text: at c, Fig. 3. The armature is firmly fixed to the shaft, and is kept from changing
its shape during rotation by means of the wooden discs i, i, which embrace the
coils on the inner parts of the ring, and which are bolted together and fastened to
the shaft by the screws and collar shown in the Figure, and by means of the outer
rings of wood and metal 11, 12, which are bolted together, embracing the outside
of the ring. All the coils of the armature form one closed circuit, but the ends of
one thin coil and of its neighbour are also fastened to an insulated rod of
copper gh, there being as many such rods as there are of thin coils on the
armature. The ends g of these rods are fixed to an insulating ring of ebonite,
which is fastened to the wood centre i and rotates with the shaft. The other ends
of the rods are quite free, being only separated from each other by air. From
these rods electric currents are taken away by means of four contact pieces, which
rub or roll on them; m m³, m m³, are four electro magnets bolted at the ends m, m,
to a ring of iron, and to the cast iron frame 8 8. At their ends m¹, m¹, they are
firmly fixed in a frame of wood. The cores of these electro magnets terminate in
iron pole pieces of the sectorial shape shown at m, m, Fig. 2, which are close to
the armature; nn1, n n¹, are four similar electro magnets, fixed in the same way
on the other side of the armature in such a way that n¹ and m¹ do not come
opposite to one another, but in the position shown in Fig. 3. In fact, the system
of magnets n n¹, is rotated about ten degrees relatively to the system m m³, and a
line joining the middle points o o, of two opposite pole plates makes an angle of
about 50 degrees with the direction of motion of the ring at that place. The
electrical connections are such that n' and m², Fig. 3, have opposite polarity, so
that between them there is formed an intense field of force, whose lines are
nearly all at right angles to the planes of winding of the coils passing through
it. Fig. 4 shows a small machine, in which my Invention is carried out in
a different manner. A, B, C, is a tubular electromagnet. The magnetic field is
most intense between the pole pieces m¹ and n', of which there are four sets. An
armature, the direction of winding of whose coils is seen at D, rotates as shown in
the Figure. In this case poles of only the same name are found on one side of the
ring. By using two tubular magnets for one ring I obtain as many north as of
south poles on one side of my ring. When using dynamo electric machines instead
of voltaic batteries in sending telegraphic messages I make machines the internal
resistances of whose rotating armatures are as nearly as possible equal to the
average lengths of the telegraphic circuits through which messages have to be sent.
Such dynamo-electric machines as have hitherto been tried for this purpose have
bad armatures of resistances from one-quarter of an ohm. to a few ohms. The
armatures of the dynamo machines used by me for telegraphic purposes will have
resistances greater than twenty ohms, and may have resistances of several thousand
ohms.
Having thus described the nature of my Invention and the manner of performing
the same, I would have it understood that I claim,-
First. The use of coils on a moveable armature, such that the plane of each
winding makes an angle, not a right angle and not zero, with the direction of
motion, substantially as described.
Second. The method of placing magnetic poles of opposite polarity near each
other on opposite sides of an armature of coiled wire, so that nearly all the lines of
force make a decided angle of from 20 to 70 degrees with the direction of motion,
or so that a straight line drawn from the centre of one pole piece to the centre of
the other makes an angle of from 20 to 70 degrees with the direction of motion of
the armature at that place, substantially as described.
Third. The use of an annular or prismatic armature consisting of coils wound at
right angles to, or making any other angle with the direction of motion when soft
iron it not used as a core, that is, when the coils are fixed on any other core than
one of soft iron or when they have no core, substantially as described.
Fourth. The methods of manufacturing an annular armature of coils with or
without a core, substantially as described.

page_text: Fifth. The method of constructing a commutator, consisting of rods of metal,
which shall be well insulated from one another, and which shall cause little loss of
power by friction, because of the rods being near together and insulated by air at
the place where rubbing occurs, and far apart where they are fastened to the more
rigid insulator which keeps them in their proper relative positions, substantially as
described.
Sixth. The method of using dynamo machines of internal resistance greater than
20 ohms. for telegraph work, substantially as described.
In witness whereof, I, the said John Perry, have hereunto set my hand
and seal, this Sixteenth day of September, in the year of our Lord Eighteen
hundred and eighty.
JOHN PERRY. (LS.)