Improvements in Dynamos.
Year: 1895

page_text: Date of Application, 24th Sept., 1895-Accepted, 24th Sept., 1896
the County of Northampton and State of Pennsylvania, United
America.]
Improvements in Dynamos.
States OL
I, DUGALD CLERK, of 18 Southampton Buildings, Chancery Lane, London, W.C.
Engineer, 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 relates to the general construction and arrangement of dynamos
and the winding of the field coils thereof, the object particularly in view being the
production of a dynamo in which the usual winding of the armature may be
dispensed with and the construction of the dynamo made more simple and reduced
in cost. The several features of the invention are fully described hereinafter and
are represented as embodied in the dynamo illustrated in the accompanying
drawings in which―
Figure 1 is a plan view, partly broken out to show details of construction.
Figure 2 is an end view, partly in cross section.
Figure 3 is a perspective view of the armature disc, a commutator of ordinary
construction being indicated by dotted lines.
Figure 4 is a perspective view of the commutator just referred to.
Figure 5 is a partial plan view, the arrangement of the brushes to bear directly
upon the armature disc.
Figures 67, and 8 are diagramatic views illustrating the winding of the field
coils.
Figure 9 is a plan view of a partially completed field coil to illustrate the
winding.
The core A of the magnet consists of a bundle of soft iron wires laid in
parallelism and held together in a substantially cylindrical form. At each end of
the bundle and firmly attached thereto is a soft iron annular disc B, which for
convenience and to indicate its functions, is termed a spreader. These annular
discs may be brazed to the ends of the bundles or heated and shrunk upon the
ends of the bundle or otherwise securely held to the ends of the bundle in
any convenient manner. They form virtually a part of the core and are pre-
ferably as large again as the diameter of the core, their function being to enlarge
or spread the area of the magnetic field. As a matter of convenient construction
longitudinal rods C, C are laid parallel with the bundle forming the core and are
extended through the spreaders to hold all parts together firmly. These rods may
be embedded among the outer wires of the core which are somewhat shorter than
those forming the body thereof and are held in place by the spool heads D, D.
In winding each field coil. two special features are adopted, which contribute
materially to the production of an efficient dynamo, one of them being of particular
importance. The first of these features is the decrease of the size of the winding
wire or wires from the core outward. One, two or more layers immediately about
the core are formed of heavy wire, as indicated at e, e. The one, two or more
layers next outside of these are formed of small wire as indicated at f, f, and so on
to the outside of the spool, the finest wire being on the outside. The number of
sizes of wire employed and the number of layers formed with each size may be

page_text: varied more or less as desired or as found productive of the best results under
particular conditions of use. For a purpose to be referred to hereinafter the ends
of successive wires of different sizes are not connected directly but are brought out
at the end of the coil, as clearly shown at e', e, f, f', and g¹, g', in Figures 1
and 2. The ends are preferably provided with jacks e, f, g, and a plug board H
is mounted in proximity to the magnet so that the ends of the different wires can
be coupled together in any desired manner.
The other feature of the winding and one which is particularly important in the
attainment of the desired result whether wires of different sizes be employed or
not, is the reversing of the direction of winding of the wire about the core at the
end of every second layer. This is clearly illustrated in Figures 6, 7 and 8, each
one of which figures indicate the manner of winding of the successive layers of
wire upon a single core, there being for each double layer two representations of
the core so that the direction of winding both to and fro upon the core may be
indicated. Thus in Figure 6 the heavy wire e which lies nearest to the core is
represented as being wound about the same in the direction of movement of the
hands of a watch in both the first layer, when the winder is moving forward, and in
the second layer, when the winder is moving back toward the end at which its
movement commenced. To make the illustration clearer but two layers of the first
or heaviest wire are represented but it will be understood that there may be two,
four, six or more as may be found desirable, and that at the end of every second
layer the direction of winding is reversed as more fully illustrated with respect to
the second and third wires.
The second wire is wound upon the last layer of the first wire with the
direction of winding reversed, that is to say, if the direction of winding of the two
layers immediately preceding was in the direction of movement of the hands of the
watch, the direction of winding of these next two layers, to and fro, is opposite to
that of the hands of a watch. Of the second wire f, as of every other wire there
may be two, four or more layers and as before stated the direction of winding is
reversed at the end of every second layer; consequently, as indicated in Figure 7
and in Figure 8 each wire, if not cut and having its end extended out from the
coil, must be bent upon itself to form a bight, as at fx in Figure 7, and wound on
over the preceding layer in a direction opposite to that in which such preceding
layer was wound. Such bight is secured in any convenient manner, as by a bit
of taping, and it is evident that wherever there are four, six or more layers formed
from one wire there will be a bight at the end of every second layer until the
end of the wire is reached. The winding of the third wire y and of every
successive wire is conducted in a similar manner. It will be understood that
whether a single wire be used or several different sizes of wire be used in
succession, the direction of winding is reversed at the end of every second layer.
It will also be understood that when several wires of different sizes are used each
wire forms an even number of layers and that the ends of each wire are brought
outside of the coil to be connected up in any one of the several different ways
which are possible, as may be found most desirable.
A yoke I of soft iron is secured to the spreaders at one end of the coils, having
a width preferably equal to the diameter of the spreaders and having a length
preferably equal to half the length of one of the cores.
Although the construction of the field magnet already described is not only the
preferred construction but forms a part of the invention set forth herein, and
although the armature which is presently to be described is also that which it is
preferred to use with the described magnet and itself forms a part of the invention,
the described field magnet and armature co-operating in the attainment of the
improved results and being to an extent interdependent, nevertheless it is to be
understood, so far as either the field magnet or the armature is concerned, con-
sidered separately, that the features of novelty in the one are restricted by
reference herein to the specific construction of the other. The preferred armature
consists of a disc K of soft iron, cut radially, as indicated at k, k, nearly but not

page_text: quite to the centre to form a series of segments k¹, which are insulated from
one another except at their apexes where they are united to the common hub ..
This armature is mounted to rotate in front of the poles of the field magnet,
cutting transversely across the magnetic fields. It may be secured to a shaft L.
which has a pulley L' and is supported to rotate in suitable bearings M, M. As
represented in Figure 1 an ordinary commutator N may also be fixed upon the
shaft L with its several bars in contact with the hub of the disc K, the-
brushes O, O bearing upon the commutator and being carried by an adjustable
rocker P as usual. The usual commutator may be dispensed with, however, and
the brushes O, O arranged to bear directly against the segments of the disc K, as
shown in Figure 5, the rocker P¹ being modified to support them properly. In
this arrangement the commutator is virtually incorporated with the armature-
itself.
Practical tests of field magnets constructed as described demonstrate that
the magnetic fields produced are of great density and that highly satisfactory
results in the production of the induced current can be secured, even with an
armature of construction shown, in which the usual windings are wholly dispensed
with. Moreover, an almost endless variety of changes of the condition of the
magnetic fields with the. consequent varied effect upon the induced current, is
made possible by the provision made for connecting up in many different ways
the several wires of which said field coil is composed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is,
--
1. In a dynamo, the combination with an artnature, commutator and brushes, of
a field magnet having its coils formed of a series of wires, the ends of said wires
projecting from the coil, and means whereby said wires may be connected and
disconnected as desired, substantially as shown and described.
2. In a dynamo, the combination with an armature commutator and brushes, of
a field magnet having its coils formed of successive layers of wires, the direction of
the wire being reversed at the end of every second layer, substantially as shown
and described.
3. In a dynamo, the combination with the field magnet and brushes, of an
armature mounted to rotate in front of the poles of the magnet, the said armature
consisting of a disc cut nearly to the centre to form separate segments connected
to a common point, substantially as shown and described.
4. In a dynamo, the combination with the field magnet and brushes, of au
armature mounted to rotate in front of the poles of the magnet, the said armature
consisting of a disc cut nearly to the centre to form separate segments, and means.
to support the brushes in contact with the disc, substantially as shown and
described.
5. In a dynamo, the combination of a field magnet, having its coils formed of
successive layers of wire, the direction of the wire being reversed at the end of
every second layer, and an armature mounted to rotate in front of the poles of said
magnet and consisting of a disc cut to form separate segments, substantially as
shown and described.
MARKS & CLERK,
18 Southampton Buildings, London, W.C., and
13 Temple Street, Birmingham, Agents for the Applicant.