Improvements in and relating to Electric Motors.
Year: 1892

page_text: Date of Application, 27th Feb., 1892-Accepted, 13th Aug., 1892
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Motors.
I, CARL COERPER of Ehrenfeld Cologne in the Empire of Germany Director
of the Helios Company, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
My invention relates to electric motors.
The object of this invention is the construction of an electric motor which can be
actuated by means of alternating currents while obtaining a great useful effect and
allowing the start to be effected under a load which was not heretofore possible.
This is obtained by the construction forming the subject of this invention, that is to
say, by arranging between the pole pieces and the fixed iron armature core or (when
the latter does not exist) between the pole pieces of the magnet, a rotating drum,
ring or disc armature which is made of subdivided magnetic material connected to
the wires or conductors conveying the electric current for the purpose of forming a
magnetic bridge of the smallest possible resistance between the magnetic poles or
between the magnet and the said iron armature core and of allowing a steady
arrangement of the current conveying coils. The invention is illustrated in the
accompanying drawing in which
Figure 1 is a front view partly in section of a motor provided with the improved
arrangement.
Figure 2 shows to an enlarged scale a cross section of the fixed iron armature
core and of the drum armature Figure 1.
Figure 3 is a longitudinal section partly in elevation of the arrangement shown
in Figure 1.
Figure 4 is a longitudinal section of a somewhat modified construction of the
arrangement shown in Figure 1 and the mechanism which receives the drum
armature and is mounted on a hollow shaft surrounding the fixed shaft a on the
right and left hand side.
Figure 5 is a similar section to that shown in Figure 2 showing the application
of the invention to a ring machine.
Figures 6 and 7 show a front and a side view respectively of the arrangement of
the new ring or disc armature in two other forms of machine without fixed iron
core in order to show that the improved construction, that is to say, the use of the
peculiar rotating drum disc or ring armature arranged between the pole pieces and
the fixed armature core or between the magnetic poles alone can be applied to
every form of machine however different it may be.
In the drum machine shown in Figures 1 to 3 the armature core, which
together with the shaft a is stationary, is provided with the coils or winding dd,
through which the current passes, and which always produces the magnetic
poles S and N at the same time as the coils or winding c and cof the magnet
produces the poles N and S in the pole pieces of the field magnet. By this
arrangement the counter electromotive force of the machine is materially diminished.
The arrangement of the rotary coils or winding e, e offer considerable difficulties.
This winding must be very stable, as it has to receive the pull of the machine, it
must not moreover have too large dimensions radially, otherwise the magnetic
resistance between the armature core and the pole pieces N and S would be
increased to an injurious extent. The rotary armature winding, by reason of the
losses resulting therefrom, must not be arranged upon a solid metal support nor be
made of solid magnetic material; moreover in drum and ring machines the
windings must be made of subdivided magnetic material, otherwise the magnetic
lines of force would be conducted away. My arrangement for obviating these

page_text: inconveniences, is as follows. Upon a nave of non-magnetic material, Figure 3 is
fixed a framework composed of, a number of irons or sections.
The irons or sections which may be made of various forms as shown in
Figure 2 and which form the skeleton which is firmly connected with the nave,
and therefore rotates upon the fixed armature core, constitutes a magnetic bridge
for the passage of the lines of force from the pole-pieces N and S to the armature
core . Round these sections the current-conducting wire is wound. The rotary
armature therefore consists of single elements for example the iron section and
the wire the iron always forming the magnetic conducting material (the magnetic
bridge) which is surrounded by the current-conducting material (the wire winding).
The peculiarity of my arrangement therefore consists in the fact that a magnetic
Bridge of subdivided magnetic material is formed for the passage of the lines of
force from the pole pieces N and S to the armature core at the same time
ensuring the stable arrangement of the windings conducting the currents. Here
it is not necessary that the magnetic material shall be insulated from the windings
conducting the currents in fact the magnetic material may always be employed in
conjunction with a material forming a better conductor for the currents.
The mechanical arrangement may be made either according to Figure 3 or
Figure 4. In Figure 3 the armature core is by means of the shaft a- firmly
connected with the pedestal . The axis rotating with the nave is supported.
in the two bearings m m. The iron frame-work e secured upon the nave therefore
runs freely round the stationary armature core band within the pole pieces N S.
The current-conducting armature windings mounted by means of the iron frame-
work are suitably joined to the commutator l.
1
In Figure 4 the shaft a passing from end to end is stationary together with the
armature core b. The shaft is bored to enable the current to be conducted to the
armature winding d d Figure 2. On both sides of the armature core the naves f
are arranged to turn upon the shaft a. The naves fare firmly connected,
parallel with the shaft, between the armature core and the pole pieces by the
frame-work e e. With the rotary naves ff are connected at one end the belt
pulley or a toothed wheel or the like and at the other end the commutator l.
The current conducting armature windings are arranged as in Figure 3. ***
The same object can be attained in a similar manner in the kinds of machines as
represented in Figures 5 to 7.
+J
Figure 5 is a ring machine. The armature core bb is stationary and may be
provided with the winding d d. The rotary armature windings conducting the
currents are mounted in the ring e e in such a manner that they intersect the
magnetic lines of force in their rotation. The ringe contains again as
mechanical parts of construction, and as a magnetic bridge, magnetically con-
ducting material and current conductors. The same arrangement may also be used
in the case of flat ring machines.
:
The arrangements of the machines in Figures 6 and 7 may very well be employed
for any purposes, if with these magnetic fields is combined a disc armature with a
Gramme commutator. The stationary armature core is here dispensed with. .On
the other hand the rotary ring or the disce e is again inade of magnetically con-
ducting material and current conductors. The current-conducting windings are
guided as in the known disc armatures and provided with a Gramme commutator.
My arrangement may be used in multipolar machines as well as in two pole
machines.
All the arrangements herein before described may be modified so that the
machine elements of the machine stated in the description as being rotary may be
stationary, those stated to be stationary being made rotary.
"
..
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 :-
First. An electric motor comprising a magnetic field with a drum or ring

page_text: armature separated from the armature core, or of a magnetic field with a ring or
disc armature without an armature core, the said armature being made of sub-
divided magnetically conducting material in combination with current conductors,
for the purpose of forming a magnetic bridge of as little resistance as possible
between the magnet poles, or between the magnet and armature core, and ensuring
the stable arrangement of the current-conducting windings.
81
Second. An electric motor which, besides the ring, drum or disc forming
magnetic bridge possesses an armature core which is provided with a magnetising
winding.
Dated this 27th day of February 1802
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.