Year: 1886

page_text: I, HERBERT JOHN ALLISON, of the firm of Allison Brothers, of 52 Chancery
Lane, London, in the County of Middlesex, Patent Agents, 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:-
The present invention relates to improvements in dynamo electric machines, and
also in electric motors since some of the constructions herein described are applicable
to both.
The principal object of the invention is to secure a simple and efficient dynamo
electric machine adapted to furnish a constant potential, or nearly so, and an
electric motor for the purpose of maintaining when fed by a current of constant
potential a nearly constant speed.
Fig. 1, represents in elevation and partly in section a machine constructed in
accordance with my invention.
Fig. 2, is an end elevation of the same.
Fig. 3, is a diagram of the circuits.
Fig. 4, is an exterior view of the armature core unwound.
Fig. 5, is a longitudinal section of the armature core.
Fig. 6, illustrates the winding of the armature.
Fig. 7, is a diagram of the winding.
Fig. 8, is a side view of the commutator cylinder.
Figs. 9, 10, 11 and 12, are diagrams illustrating the magnetic actions during
operation.
Fig. 13, shows an adjustable arrangement sometimes employed.
In Fig. 1, F, is a section of the core of one of the field magnets, which is flanged
so as to be joined to a corresponding flange of the field magnet F, at the other end
by an exterior casing of iron, or iron bars.
.
Each of these field magnets consists as shown, of a short cylinder of iron, or
other suitably shaped piece, the end of which presented to the armature A, is
hollowed out to form a concavity conforming to the spherical outline of the
armature. Exteriorly to the part F, and surrounding it, as usual, are coils of
copper wire C, C, constituting the coils of the field magnet proper.

page_text: The armature A, constructed as hereafter described is mounted on a shaft, seen
end-on at X, in Fig. 1, and seen as extending from the pulley and across the
machine in Fig. 2.
A suitable frame with feet G, G, is provided for the support of the shaft and
various parts of the machine.
The armature is wound with wire which revolves along with the said core. The
mode of winding will be described hereinafter.
Supported so as to surround the armature core A, but not moving with it is a
coil or coils B, B, B¹, B¹, placed as shown in Fig. 1, so as to permit the free
revolution of the armature internally thereto.
These coils may be described as stationary loops of wire, preferably bent to
avoid the shaft, and whose planes of position are inclined preferably as shown in
such manner that the inclination is backward with reference to the direction of
revolution, as indicated by the arrow. The purpose of this arrangement will
be afterwards described.
In Fig. 2, P, is the driving pulley. The bearings of the shaft are shown at D,
and E, which bearings are suitably supported on the iron frame work carrying the
feet G, G, and extending from the flanges on F, F", being securely bolted thereto.
The bearing A, is on an arm of bracket H, fastened to the framework, which
bracket serves also as a support for the yokes and attachments of the commutator
brushes. The commutator is indicated at K.
In Fig. 3, the modo of connecting is shown. The commutator brushes J, J,
indicated as bearing on the commutator cylinder K, in a suitable position are
attached respectively to connections leading through the coils C, C, as shown,
while the circuit from J, J, is continued through the coils B, B, and B³, B¹,
themselves arranged in series or in multiple are with each other, and transversed
by the current generated by the machine and supplied to the electric mains.
The work, such as a number of incandescent lamps W, W, arranged in multiple
arc from the mains or conductors leading from the machine (the number of which
lights W, W, may be varied ad libitum) is fed by the current developed, save that
portion which passes through C, C. The coils C, C, are therefore in shunt to the
work W, W.
In Fig. 4, the armature core A, is shown mounted on a shaft ready to be wound.
It consists of a portion of a sphere from which two segments have been taken in
the polar portion through which the shaft passes so as to leave two flattened
surfaces thereat. The core is built up bodily, either of a mass of iron wire wound
around a shaft between suitable guiding plates M, N, figure 5, or preferably, of a
number of sheets of iron or iron discs of varying diameter as seen in Fig. 5, piled
up around a suitable form carried by the shaft and secured between such plates..
Projecting pins p, p, serve as guides in winding the armature conductors and are
usually carried by the plate or flange at each end of the armature core. I find it
of considerable advantage in the use of such an armature core to construct it with
connecting wires L, L, equal in number to the segments to be used in the commu-
tator, or to the number of coils or divisions of a single coil on the armature. The
leading wires or connecting wires L, L, pass, as shown in Fig. 5, (sectional view)
from near the périphery of the armature in wardly through a proper space provided
in the armature core itself, and out through the end plate N, along the shaft.
These leading wires are carefully insulated and preferably enclosed between discs
of insulating material (shown in black) allowing them to be spread out radially
from near the shaft.
Other constructions permitting the carrying of the wires L, L, from along the
shaft to a point at or near the greatest exterior circle of the armature core will
suffice, but the construction shown is simple and efficient.
The plates M, N, may be keyed securely to the shaft, and where it is not
desirable to have the sheet iron discs extend close to the shaft an interior tube or
other support may be provided to hold them concentrically with said shaft.

page_text: It is also preferable to leave small spaces g, g, between the discs at suitable
points, blocks of any suitable material being inserted to hold them apart.
These spaces permit convertion currents to circulate through the body of the
armature and help to dissipate heat, though it is desirable to construct the arma-
ture of sheets of iron of such thinness that very little heat is generated by the
change of the magnetism.
The mode of winding may be described as follows, aud the result of the winding
is exhibited at Fig. 6. Beginning at any convenient point a suitable wire or
several wires are carried around the armature in diametrically opposite spaces
between the pins p, p, provided as guides in winding each space for wire being
filled only half. When this is done the wire is carried diagonally into the next
space and this passage is made on the armature, as seen in Fig. 6, at that portion
of the core having the largest diameter, and where a space is left vacant between
the coils due to the form of the armature and its varying diameter as the coils of
wire pass over it. This will be understood when it is stated that the periphery at
which the pins p, p, are located is smaller than that at the middle line (dotted in
the figure) so that wire which follows and fills the spaces between the pius leaves
open spaces between the coils at the central position. But the wires L, L, through
which connection is made to the commutator cylinder are arranged to have one end
of each open into one of these spaces and in regular succession, so that a joint from
said wire is easily inade with the projecting end and the portion of the coil passing
near thereto from one coil space to another. Thus wire a, in Fig. 6, will be con-
nected to L, one of the terminal wires projecting radially from the armature core,
and being a continuation of a corresponding wire led along the shaft as seen in
Fig. 5.
In armatures wound upon cylindrical cores no such facility for the connection of
coils exists, and my construction therefore furnishes a simple method, differing
from others, of winding a continuous wire around the armature core, securing
ample space for the production of a good joint with the commutator leading wires,
and securing simplicity and ease of winding.
To complete the winding of the armature it is only necessary to continue half
filling the coil spaces with wire in regular succession around the core, and making
the suitable joints with the leading wires until the core is covered with wire.
At this time it will be found that one half of the leading wires have been con-
nected to the wire of the winding. It is now only necessary to continue the
winding, filling the spaces completely, while the joints are made with the connecting
wires between what now become the exterior coils of the system.
The finishing of the winding takes place in connecting the first end to the last
end of the wire used in the winding.
To elucidate the winding Fig. 7, may be referred to where there are supposed to
be eight leading wires L, L, L, L, &c., and eight coils consisting of two series, the
under series and the outer series all constituting a single unbroken wire.
Assuming the coil D, to have been laid on, then in passing to the adjoining space
described, the connection to a leading wire is made and this is repeated in passing
from coil 2 to 3, and from 3 to 4, at which moment the armature core has received
the entire series of coils on its exterior, then a similar joint is made in passing to
the first coil of the second series and the last joint to the leading wire, in passing
from the last coil of the second series to the first coil of the first series.
Any number of coils may be thus wound on the armature, if the number of
spaces provided therefor are sufficient.
The winding it will be seen is similar to what is known as the Siemens winding,
but the connections are taken out in an entirely novel manner, permitting the
close winding of a single wire or group of wires.
The wires L, running along the shaft from the coils R, to the commutator
segments respectively are insulated from each other as usual, as shown in Fig. S.
The revolution of the armaturo in the magnetic field generates currents in the
coils, which, as in the Siemens construction, are carried out to the strips in the

page_text: commutator and are there conveyed to the circuit by the brushes bearing upon
the commutator.
The position at which the brushes are set on the neutral line, with an enormous
strength of field magnetism, and an armature core whose magnetic effects are
comparatively very weak, as when but very little current flows in its coils, or
when a few connections exist upon it, will be in a line almost at right angles with
the magnetic line induced by the field poles, as is well understood.
It is inconvenient, however, to give to the machine such enormous field strength,
and to diminish the armature convolutions to the degree required, as it limits the
capacity of the machine, and makes the field expensive to produce. In consequence
a lower field strength is selected and an armature of more convolutions utilized, but
in this case the position of the neutral line at which the brushes should be placed
is forward to a greater or less degree, depending upon the work demanded of the
armature. Thus, in Fig. 9, N, S, represent the field poles, A, the revolving arma-
ture, K, the commutator, and B, the brushes. When the current is doing little
work, that is when the current flowing through the coils is small, as for a few
lamps, or devices, supplied in multiple arc, the brushes B2, B3, should be placed
to touch the commutator on a. line as t, t, nearly at right angles to a line joining
the centers of the field poles.
In practice a slight inclination is found to exist in the direction of revolution,
depending upon the speed of rotation of the armature and other causes.
If now the load on the armature or the work done by it be increased, the strength
of the field magnetism remaining the same, or even being increased to a limited
extent, the position at which the brushes should touch the commutator to avoid
spark will move forward as at t¹, t¹, Fig. 9, owing to the reaction between the
magnetism of the armature and the magnetism of the field and the consequent
distortion of the magnetic field. It is desirable, however, to avoid the necessity
of constant readjustments according to the load. To secure this end I place around
the armature core, as in figures 1, and 3, the coarse wire coils B, B, B1, B¹, and in
an angular position backwards. If the coils be made movable this position may
be readily adjusted.
These coils are represented in figure 10, and as has been stated, (Fig. 3,) are
traversed by the current fed to the work, which current is of varying amount.
The action of the currents traversing the coils B, B, B1, B, upon the armature
core, is such as to develop magnetism in it in a direction at right angles to their
plane, or axially to them, with the result of readjusting the neutral line, as the
current increases in the armature to a practically constant position, a little forward
of a line passing between the field poles N, S, centrally.
This neutral line so established is shown in Fig. 10, t¹, t'.
To make clear the manner in which the results are secured I refer to Fig. 11, as
exemplifying the magnetic action when the coils B, B, B', B¹, are absent. The field
poles tend to establish in the armature core a polar line or magnetic condition whose
direction is seen in the line N¹, S¹, while the current generated in the armature itself
tends to establish a polar line in the same armature core in the line N2, S. Tho
resultant line of real magnetism existing in the armature core will, however, bo
N³, S3, a line drawn intermediately between the line N¹, S¹, due to the inductive
influence of the field, and N2, S2, due to the currents flowing in the armature, but
approaching more nearly the direction of N¹, S', on account of the superiority of
the magnetic effects of the field to that of the armature currents. The direction of
revolution in all these cases is indicated by a curved arrow.
In Fig. 12, N¹, S¹, represents as before the induced magnetism or axial line in
the armature core induced by the field, while the line N, S', represents the line of
magnetism induced by the action, of the coils B, B, B1, B1, the direction of the
current sent through such coils being made such as will assist the action of the
field magnets themselves upon the armature core, but will produce a magnetic axis
not quite coinciding with that produced by the field magnets themselves, but which
will be displaced as indicated at N*, S, instead of being in the direction N¹, S',

page_text: which would have been the direction had the coils B, B, B1, B¹, instead of being
inclined been placed with their planes at right angles to the line N, S, or with
their planes parallel with the plane of the field magnet wire C, C, Fig. 3, with the
current unchanged in direction.
In Fig. 12, the line N2, S3, represents as before, the direction of the magnetic
axis induced by the flow of current in the armature coils. It will now be easily
seen, that should the influence of the coils B, B, B1, B¹, exist alone with that of the
armature currents, supposing such were possible, a resultant magnetic axis would
be produced which might easily be made coincident with the line N', S', or the
direction in which magnetism is induced by the field magnets themselves acting
alone. Hence by the construction which I have described it is easy to secure a
neutral point a little forward of the line at right angles to that joining the axis of
the field poles, which undergoes practically no change from light load to full load,
or from weak current developed by the armature to the strongest currents which it
may yield, this feature being due to the stationary armature encircling coils B, B,
B¹, B¹, overcoming the distortion of the magnetic field by their being placed in an
inclined position as described.
I find also in the practice of my invention, that the proportions of the coils
B, B, B1, B¹, to the rest of the circuit may be made such as to secure a constant
potential at the commutator brushes, and a difference of electro motive force at tho
terminals of the machine of constant amount, this second feature being alike due
to the effect of said coils acting upon the armature core enclosed by them so as
to prevent a weakening of the magnetic action when the armature coils are
discharging heavy currents.
The position of the coils B, B, B', B³, can be made adjustable by mounting them
upon a suitable support permitting their movement. This is indicated in Fig. 13,
and consists of a stationary ring R, and a second ring or portion of a ring bearing
on the interior surface, to which second portion the coils B, B, B1, B¹, are secured.
A proper handle H¹, attached to the parts upon which the said coils are mounted
may be provided to set the coils in position, when the proper position has been
selected.
The screw D¹, serves merely to clamp the portions holding the coils B, B, to the
outer ring R2. This position having been selected requires no change unless the
other portions of the apparatus are changed. It is preferable however, to select a
fixed position for the coils and use them at all times in the best fixed position,
constructing them so as to dispense with the adjustability of the coils B, B, B1, B¹,
thereby securing cheapness and greater simplicity.
I do not however wish to limit myself to the use of coils with a fixed position
merely.
I have described my present invention as applicable to a dynamo electric
machine. The improvements are equally applicable to the case of motors, which
are simply reversed dynamo electric machines, and the changes which are to be
made in applying my invention to convert the dynamo electric machine into a
motor are only those changes which are made usually in such cases, and well under-
stood by those skilled in the art. I have therefore not deemed it necessary to
describe these alterations which are simply those of connection to the feeding
circuit.
The mechanical elements embodied in my present invention will be unchanged,
as the alteration of circuits will involve no change of structure.
Having now particularly described and ascertained the nature of my said
invention, and in what mauner the same is to be performed, I declare that what
I claim is
1. In a dynamo electric machine or motor, field magnet cores wound with wire
connected in derived circuit or shunt to the work, and an armature surrounded by
stationary coils traversed by the main current of the machine, substantially as
described.

page_text: 2. In a dynamo electric machine or motor, an armature surrounded by stationary
coils applied in the manner described to correct the tendency to distortion of the
magnetic field by the reaction of armature and field magnetism, substantially as
described.
3. In a dynamo electric machine or motor, the combination with the revolving
armature, of stationary.coils mounted on an adjustable support, whereby their plane
of winding may be varied with relation to the line of field magnetism, as and for
the purpose described.
4. In a dynamo electric machine or motor, an armature wound with a continuous
wire, and having connections therefrom to the commutator, in combination with
commutator brushes connected to a system of field magnet coils in derived circuit
around the work, and connected in series to the work through a system of stationary
coils surrounding the armature core.
5. In a dynamo electric machine, an armature core constructed with spaces
leading to the interior of said core, in combination with leading wires passing
through such spaces for connecting the armature coil system to the segments of the
commutator..
6. An armature core composed of end plates M, N, a series of discs of varying
diameter, spaces g, g, dividing the discs into groups and leading wires inserted into
passages made in the body of the armature core, as described.
7. In a dynamo electric machine, a system of coils wound upon an armature
whose peripheral surface is a portion of a sphere or ellipsoid, said system of coils
being wound in two series, overlaying and underlying, with the wire of one coil
in a series passing to the next coil in the series diagonally across the space existing
between the coils at or near the place of greatest peripheral diameter of the
armature.
8. In a dynamo electric machine or motor, a spherical armature wound with a
series of coils connected to one another diagonally across the spaces at or near the
greatest peripheral diameter of the armature core.
9. In a dynamo electric machine or motor, leading wires passing through a
portion of the armature core, and connected with the coil system at the places
where the coils are separated by passing over the greatest peripheral diameter of
the curved armature core, as described.