IMPROVEMENTS IN MAGNETO- ELECTRIC MACHINES OR MACHINES FOR GENERATING ELECTRICITY
Year: 1878

page_text: LETTERS PATENT to Michael Radcliffe Ward, of 15, Gloucester Place, Brighton,
in the County of Sussex, for the Invention of "IMPROVEMENTS IN MAGNETO-
ELECTRIC MACHINES OR MACHINES FOR GENERATING ELECTRICITY."
Sealed the 13th December 1878, and dated the 9th October 1878.
PROVISIONAL SPECIFICATION left by the said Michael Radcliffe Ward at
the Office of the Commissioners of Patents on the 9th October 1878.
MICHAEL RADCLIFFE WARD, of 15, Gloucester Place, Brighton, in the County of
Sussex. "IMPROVEMENTS IN MAGNETO-ELECTRIC MACHINES OR MACHINES FOR
GENERATING ELECTRICITY."
This Invention has for its object improvements in magneto-electric machines or
machines for generating electricity. In machines of this nature now in use a
rotating armature is employed; it is of cylindrical form, wound inside and out
with covered wire which is coiled around it in directions parallel to the axis of the
cylinder. This armature is made to revolve whilst its periphery is in close
proximity to the pole pieces of electro-magnets. But in this arrangement the pole
pieces are necessarily separated from the cylindrical iron core of the wound armature
by somewhat more than the space occupied by the coils on its exterior, and this
detracts from the efficiency of the machine. According to my Invention I provide
grooves in the cylindrical core to receive the coils of covered wire, and when the
armature is wound the coils fill these grooves, so that the wound armature is
approximately cylindrical. When this armature is mounted in the machine the
[Price Gd.]

page_text: portions of the core between the coils are only separated from the pole pieces of the
electro-magnetic inductors by a clearance sufficient to avoid risk of actual contact
when the inachine is in use. In place also of forming the core of a single piece I
build it up of bars nearly of H form but with the sides somewhat inclined, and a
number of these bars placed side by side form the grooved cylindrical core.
In machines for producing alternating currents I employ a wound cylinder of
comparatively large size with the bars separated the one from the other by a dia-
magnetic material, such as copper, and in place of rotating this cylinder I cause
electro-magnetic inductors to revolve within it. In some cases I apply also electro-
magnetic inductors on the outer side of the wound cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Michael Radcliffe Ward in the Great Seal Patent Office on the 9th
April 1879.
"
MICHAEL RADCLIFFE WARD, of 15, Gloucester Place, Brighton, in the County of
Sussex. IMPROVEMENTS IN MAGNETO-ELECTRIC MACHINES OR MACHINES FOR
GENERATING ELECTRICITY."
From experiments which I have made in the inagnetisation and demagnetisation
of iron I find there is a very great difference in the effect which is produced on an
iron core when the influence of the magnetic or electro-magnetic inductor is on the
bare iron core and when it has to act through several layers of insulated wire.
When the inductor acts on the bare soft iron core, between which core and the
inductor there is not any barrier to the inductive influences, although the coils
themselves in which the currents are induced are perhaps further from the inductor
still the ultimate effect in the production of electricity is much greater when the
inductor acts directly on the bare iron.
In order to adapt this fact to the generation of electricity for the purpose of
electric lighting, plating, or any other purpose for which electricity generated by
dynamo-electric machines may be useful, I construct a generator, as shown in the
Drawings, both for the production of continuous direct or alternating currents.
Figures 1 and 2 shew a simple generator for the production of direct continuous
currents made on this principle, and the direct magnetisation of the core is effected
in an improved manner; Figure 1 is a sectional elevation and Figure 2 is a trans-
verse section on the line 1, 1, in Figure 1.
a, a, is the frame of the machine; it supports the axis b which is driven by the
motor and carries the coiled armature or bobbin c; d is a collector built up of
alternate blades of metal and vulcanite.
N is a north pole of an electro-magnet which forms one inductor; S is a south
pole of an electro-magnet which forms the other inductor.
The machine starts to generate electricity in the first instance by the aid of the
residual magnetism in the iron poles of the upper and lower magnets. This
residual magnetism developes feeble currents which pass around the electro-magnets
N and S which are in the circuit. Then they are made active electro-magnets and
the strength of their poles N, S, increases until their maximum strength is reached
with a given speed of rotation of the bobbin and a given resistance in the circuit.
Instead of placing the electro-magnets in the working circuit they may have a
portion of the total current passed through them, the rest of the current being
taken direct to the required work; or one machine may feed the magnets of
another. This action and method of generating the currents is not now but well
known.
Figures 3 and 4 shew a segment of the core of the bobbin or armature; Figures
5 and 6 shew a cross section of the same with the insulated conducting wire
wrapped round it. The longitudinal section shews that the wire is wrapped in a
direction parallel to the axis of the armature or bobbin in which the direct
continuous currents are induced. The bobbin shewn on the Drawing contains
twenty segments, and in each segment I lay three lengths of wire in separate coils
side by side. It will be seen that the segments or cores are made with their
greatest length parallel to the axis. I make the segment cores from iron, it may
be malleable cast iron, but I much prefer pure soft iron. In constructing the
bobbin I insulate each iron segment from its neighbour by a diamagnetic and
di-electric material, such as paper. I desire to draw particular attention to this
insulating the segments one from the other by a non-conductor, as the production
of induced currents in the core is by this means reduced to a minimum. I join the
insulated wires in which the currents are induced together, that is, the end of one
length is joined to the same radial strip of copper (forming the connection with the

page_text: brass cylinder of the collector) as the commencing end of the next length. As
there are in the generator shown in the Drawing 20 segmental pieces and 3 series
of lengths in each, there will be 120 ends; these 120 ends are joined together by
twos, as above mentioned, so that there will be 60 radial strips of copper. d in
Figures 1 and 2 is a cylinder of conducting material preferably made of a tough
hard alloy of copper, brass, phosphor-bronze, &c. This cylinder is composed of 60)
pieces, one of which is shown in detail, see Figures 7. These 60 pieces are all
completely insulated one from the other and from the shaft in which they are fixed.
They are joined to radial strips and the radial strips to the wires of the bobbin.
Thus there is of course electrical connexion through the coil between these segments
of brass in the collector. This form of collector is the one usually employed in
machines of this nature. The electrical contact between this cylindrical collector
and the magnets or external circuit is made by conducting brushes preferably made
of fine copper wire coated with silver, pressing against the collector (by means of
springs) a little beyond the centre line between the inducing magnets in the usual
way. Figure 2 shows a cross section through the centre of the collector and
through the centre of the inductors and the bobbin.
Instead of having a collector on one side of the bobbin only I can place one on
cach side; then every other series or length of wire on the core would be joined to
one collector and the remainder to the other collector.
In constructing machines from which I desire to obtain a greater number of
separate currents than two I place three, four, or more collectors on cach side of the
bobbin, so by this means I can obtain theoretically an unlimited number of separate
currents from one main generator.
Having now described the simple form of generator, shewn in longitudinal and
cross sections, Figures 1 and 2, I will proceed to describe another way of utilizing
the principle of direct core induction; it is shewn in longitudinal and cross sections,
Figures 8 and 9.
In dynamo-electric machines as usually constructed there is a considerable amount
of useless resistance in the bobbin or part in which the currents are induced; I
adopt the method shewn at Figures 8 and 9 to overcome this, and reduce the
useless resistance of the part of the machine in which these currents are generated
to a minimum. The inductors N and S are the same as before described in the
simple form of machine. Instead of causing the shaft to revolve I fix it rigidly to
the frame supporting the inductors N, S, which are the poles of electro-magnets.
Affixed to this stationary shaft are two electro-magnetic inductors N', S'; and
connexion with these inner inductors is effected by making the shaft hollow, or by
having frictional contacts; of course the former is preferable.
Now between the two inductors I cause the bobbin or armature made in the
manner before described to revolve by means of the pulley P. The pulley is fast
with the armature and the collector, and the whole rotates as before, but on, instead
of with, the shaft. I employ brass discs with slots on the periphery to fit and
support the armature cores on both sides; these brass discs are shewn in section at
D, D, in Figure 8.
Figure 9, a cross section through the centre of Figure 8, shews the relative
position of the armature and inductors.
It will readily be understood that in this arrangement there is very little useless
resistance. The armature A is constantly passing through a very intense magnetic
field, and the pole induced by induction in the armature is much stronger than if
there was only an inductor on one side instead of both, as there is here.
Again, the induced pole is stronger because the inductors act direct on the bare
iron core instead of through insulated wire.
In Figure 8 the cores of the electro-magnets are shewn in elevation without the
wire around except at M³, where it is shewn in section.
This machine, represented in Figures 8 and 9, will be found to be of extraordinary
efficiency. The form of the external inductors may of course be varied; the cores

page_text: may be made flat, the frame may be of divers shapes so long as it efficiently fulfils
its purpose, the mass of iron in the inductors may also be different to that shewn
on the Drawings, but it should have a surface relative to the core of the armature
equal to that shewn on the Drawings.
In adapting my armature to the production of alternating currents I construct a
machine which is shewn at Figures 10 and 11 in longitudinal and cross section.
Instead of having stationary inductors on the outside, as shewn in the first-described
continuous direct-current machine, I rotate a series of electro-magnetic inductors
inside a series of the cores of special form; these electro-magnetic inductors are of
opposite polarity, alternately north, south, north, south, &c., therefore the currents
which are induced in the insulated wires, which are wound round all the segments,
but shewn only in section at e, e, are of constantly changing direction.
The greater the mass of iron of course the longer the time required to magnetize
and demagnetize such iron; I therefore prefer to make the cores very small, smaller
even than shewn at Figures 10 and 11. If I require very powerful currents I
prefer to have a large number of small segments than few large ones, as by this
means I economize power for the reason stated.
In Figures 10 and 11 I is a frame which is secured to the shaft B and carries the
inductors.
e, e, are the coils wound on the H pieces in which the currents are induced; they
are shewn separately by the Figures 12.
place a diamagnetic substance, such as copper, between each segment and the
next, and I prefer a substance which is both diamagnetic and a non-conductor of
electricity, such as paper, wood, or vegetable fibre.
X shews the diamagnetic non-conductor.
In Figure 11, i, i, i, is insulating material, and R, R, are rollers of conducting
substance. By means of brushes pressing on these, connexion is made with the
electro-magnetic inductors. The rollers R, R, are attached the one to one extremity
and the other to the other extremity of the wire going round the cores of the
electro-magnetic inductors, which are so wound as to be of alternate polarity.
Figure 13 shews the core and coils in plan with the diamagnetic and non-
conducting substance between them; c is the core; d, the diamagnetic non-
conductor; the ends of the wire on the core are not shewn.
Figure 14 shews the double inductor arrangement, which I much prefer to that
in which there is an inductor on one side only.
I, I, I, I, Figure 14, are the inductors. Those two which influence simultaneously
one core are of like polarity. N, N¹, are both, say, north; S, S¹, are both, say,
south. As herein-before stated, the influence of the inductor is much more powerful
when the core has an inductor on both sides, and the influence is the greater owing
to the core being bare at some points.
In Figure 14 I may of course alter the form of the frame and method of
supporting both the cores and inductors without in any way altering the machine
electrically.
Figure 15 shews a cross section of the double inductor arrangement for alternating
currents.
In Figure 14 I' is the only inductor shewn with the wire (which conveys the
current) in section; the others are shewn with the core plates in elevation and
without the wire, and the inducing faces i, i, i, i, in section, also the plates b, b, b, b,
which hold the wire on are in section.
Wherever practicable, where I do not require it for magnetic purposes I prefer to
dispense with the use of iron, and to employ brass or bronze instead. Thus the
frames F, F, in Figure 8, I prefer to make of brass. If they are made of iron they
are uselessly magnetised by induction of the neighbouring magnets and force is
lost. Likewise the carrier frame I, Figure 10, I prefer to make of brass. In short,
I prefer to dispense with iron or steel altogether, except when I require it for
magnets or core, although I sometimes use it for the sake of cheapness.

page_text: Having now described the methods of putting my Invention into practise I
declare that I claim,―
First. The combination forming a continuous current machine, and consisting of
a rotating coiled armature or bobbin having a core built up in segments of H like
section, of electro-magnetic inductors, and of a collector, substantially as described
in respect to Figures 1 to 7.
Second. The modification of my continuous current machine, shewn in Figures 8
and 9, where internal as well as external electro-magnetic inductors are employed.
Third. The combination forming an alternating current machine, and consisting
of a stationary coiled armature or bobbin having a core built up in. segments of
H like section, and rotating electro-magnetic inductors, substantially as described
in respect to Figures 10 to 13.
Fourth. The modification of my alternating current machine, shown in Figures
14 and 15, in which rotating electro-magnetic inductors are applied externally as
well as internally.
In witness whereof, I, the said Michael Radcliffe Ward, have hereunto set my
hand and seal, this Ninth day of April, in the year of our Lord One
thousand eight hundred and seventy-nine.
M. RADCLIFFE WARD. (L.S.)