Improvements relating to Dynamo-electric machines.
Year: 1888

page_text: Improvements relating to Dynamo-electric machines.
I, CARL COERPER, of Ehrenfeld near Cologne / Rhine, in the Empire of Germany,
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:-
In the construction of generators of electricity the attainment of the necessary
velocity at which the armature has to pass through the magnetic field presents
special difficulties. Most of the machines are for this purpose driven at such a
high number of revolutions that the safety of working is apparently endangered,
and the costs of maintenance are as high as the wear and tear is great. The
development of the science of electricity. will of necessity lead more and more to
the construction of low speed machines.
In continuous current machines.a low speed can only be attained 1st by con-
siderably enlarging the armature or the whole machine 2nd by increasing the wire
lengths upon the armature or 3rd by augmenting the power of the magnetic field.
If a greater length of wire is used upon the armature and the power of the magnetic
field increased greater losses and difficulties occur in the working, whilst the enlarge-
ment of the machine materially affects the costs of manufacture.
In alternating current machines it is necessary that in a second a definite number
of changes of polarities shall be attained. This is only rendered possible by
increasing the number of revolutions or augmenting the number of the poles of
the magnetic field. In order to construct alternating current machines operating
at a low number of revolutions, very large models must therefore be used, whereby
the costs of manufacture are exceedingly augmented.
.
Low speed machines can however be made in which all the above mentioned
difficulties are obviated, if the magnetic field is caused to turn in the opposite
direction to that of the armature. The number of revolutions in the same size of
machine is thus decreased by one half. It is however impracticable to effect this
opposite rotation of the magnetic field and armature by ordinary means, such as
toothed wheels, friction sheaves, belts, or the like, because the wear and tear of these
intermediate parts would be just as large as that of the dynamo at double the
number of revolutions of the armature and a fixed magnetic field. By such an
arrangement the safety of working would also be rather decreased than increased.

page_text: The driving device constructed according to the present invention is however
different from this. For the purpose of the said invention I employ motors having
either one or more cylinders.
In motors having one cylinder, two connecting rods are actuated by one piston rod.
One connecting rod causes a special crank shaft, which is connected with the
magnetic field, to be moved in the definite direction, and the other connecting rod
causes a second crank shaft, upon which the armature is secured, to be moved in the
opposite direction. The magnetic field and armature are so arranged that the latter
rotates in close proximity to the poles of the magnetic field.
In motors having two cylinders the crank-shaft is divided, so that one cylinder with
its crank shaft drives the magnetic field, whilst upon the crank shaft of the other
cylinder is placed the armature which is caused to rotate in the opposite direction to
that of the magnetic field.
The described arrangement can of course be combined with any rotary shaft or
with any machine element moving to and fro.
In the manner above described the number of revolutions of the generators of
electricity is reduced by one half without materially increasing the costs of manu-
facture, or decreasing the safety and the useful effect of the working.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I wish it understood
that I claim;—
In the construction of generators of electricity the arrangement in which the
magnetic field and armature are rotated in opposite directions, namely by means of
two connecting rods such as are generally used in machine construction, and which
are connected either with the piston rod of a cylinder, or with two or more piston
rods of two or more cylinders.