Improvements relating to Dynamo Electric Machines.
Year: 1887

page_text: COMPLETE SPECIFICATION.
Improvements relating to Dynamo Electric Machines.
I, CARL COERPER, of Ehrenfeld, near Cologne on the Rhine, in the Empire of
Germany 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 :—
My invention relates to dynamo machines.
When dynamo machines are used for transmitting power by means of alternating
currents the solid iron masses in the machine become heated by the rapid changes of
polarization that is to say as long as the dynamo machine does not make the normal
number of revolutions, which is invariably the case at the commencement of the
operation and when the machine is overloaded the changing impulses of the currents
act partly upon the armature and partly upon the field magnets.
A considerable heating and consequently a loss of power is caused.
According to my present invention I reduce this heating and the loss of power to a
minimum, by making the cores of the armature, as well as the field magnets of thin
sheets of metal.
In the accompanying drawing the figures of which are hereinafter referred to I
have illustrated several arrangements of my invention.
Figure 9 shews the section of an improved machine whilst Figures 1 to 7 represent
side views of the machine or the armature and field magnets.
Figures 1 to 4 shew various forms of the several rings of which the armature and
field magnets are composed. These rings consist of a single sheet of metal which can
be cut up either wholly or in one place. The rings may also be composed of single
D

page_text: pieces of sheet metal. A large number of such rings are, as represented in Figure 9,
placed one upon the other and connected with each other to form a compact whole,
either by screwing them together by means of screw bolts Figure 9, or by com-
pression through the medium of suitable clamping devices. The elements thus joined
together and consisting of thin sheets of metal are provided with a suitable winding
of wire, and then combined to form a machine as indicated in Figures 5, 6, 7, and 8.
In Figures 5 and 7 the field magnet (NS) is outside, the armature inside. In
Figures 6 and 8 the magnetic field (NS) is inside, and the armature outside.
shewn in Figure 8 the magnetic field may consist of radial magnets composed of
single sheets of metal which are of Stellar shape as shewn in the drawing.
As
Figures 10 and 11 shew a similar arrangement. Here however the several sheets
of the armature and field magnets are wound one over the other like bands in the
axial direction, and the said armature and field magnets are so arranged relatively to
each other that either the field magnets or the armature is in the centre between two
armatures or field magnets Figure 10, or the magnetic field or the armature upon one
of the two sides of the armature or the magnetic field.
Apart from the improvement above described Figures 7 and 10 shew an improve-
ment in the form which considerably facilitates the transition of the magnetic lines of
force from the field magnets to the armature and enables a more complete utilization
of the magnetic current to be accomplished. Also in Figure 7 the field magnets can
be arranged internally and the armature externally; in this case the field magnets can
be made solid.
In all these constructions the sheets of metal which form the armature and the
magnetic field are simply toothed so that the wires are wound into the gaps, as first
introduced in the Weston machine. This arrangement has considerable defects
especially when the armature is inside because the wires widen up during the rotation
and in consequence of the heating, can only with difficulty be held fast. Moreover
the gaps must be of such width that the wires receive sufficient space together with
their insulation. By this means the tooth is considerably diminished and by reason
of the small surface of transition the reception of the magnetic lines of force is
reduced. Brown's construction which consists in providing closed holes in the
armature offers great advantages for the transition of the magnetic lines of force
from the magnetic field to the armature iron but the insulation can be put in only
with great difficulty, and several windings of thick insulated wires cannot possibly be
drawn in without injury to the insulation. These disadvantages are completely
obviated by the arrangements represented in Figures 13 to 17.
If upon the armature only one layer of wire is to be wound, holes a are punched
into the edges of the sheets of metal as in Figure 13. If two or more layers of wire
are to be arranged the sheets of metal are provided with correspondingly deeper
holes a as in Figure 14.
Figures 15 and 16 shew the details of the holes. On the periphery of the sheets of
metal are left laps d, d at such distances from each other that the wires can be laid in
without injury; the punched hole behind the laps d, d is made of a horse-shoe form
and of such size that not only the insulation b and c but also the required number of
wires have room; special slits may also be arranged either in the laps d d or behind,
as at e, e Figure 16, in order to give the material e a better hold. The pieces cc
are firmly inserted for holding fast and eventually for insulating the wires and must
therefore be made of durable material or be suitably composed. The holes may be
punched out simply to the shape of a horse shoe, as in Figure 17, and provided with
slits ee in front, in order to hold the wires in their position, and if necessary to
insulate them, by introducing the insulating material c. The form of the holes instead
of being horse shoe shaped can be square or otherwise.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed I declare that what I claim is ;—
First. A dynamo machine in which the armature as well as the field magnets are
made of sheets of metal.

page_text: Second. In a dynamo machine the employment of wholly or nearly symmetrical
sheets of metal of circular form for the armature and magnetic field, as described with
reference to Figures 7 and 10 of the drawing.
Third. In the sheets of metal designed for the armature of the dynamo-machine
referred to in the first claiming clause wherein however the field magnet can also
consist of solid iron masses the provision of holes which are so formed that one or
more layers of wire can be introduced in one piece, and the layers of wire are held
and eventually insulated by a strip c which is inserted, either behind the laps or
projections d, d Figure 15, of any desired shape or in the slits e, e Figures 16 and 17,
of any desired shape, thereby maintaining the surface of the armature iron, which
faces the field magnet as large as possible, and thus diminishing the resistance to the
transition of the magnetic lines of force.
Dated this 94th day of Tuno 1007
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.