Dynamo Electric Machines.
Year: 1891

page_text: Date claimed for Patent under Sect. 103 of Act,
being date of first Foreign Application (in
Switzerland),
-31st Dec., 1890
Date of Application (in United Kingdom), 23rd July, 1891
Complete Specification Left. 23rd July, 1891-Accepted, 26th Sept., 1891
COMPLETE
SPECIFICATION.
Dynamo Electric Machines.
We, HERMANN CUÉNOD, ERNEST SAUTTER, and GEORGES HOCHREUTINER,
together constituting the firm of Cuénod, Sautter and Company, of Geneva,
Switzerland, Engineers, 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 object of our invention is to avoid the main inconvenience which is
encountered in the employment of armatures with magnetic cores. This incon-
venience consists in the diminution of power and of output of machines provided
with such armatures in consequence of the expenditure of force necessary to the
magnetization and demagnetization of the magnetic masses or in other treatments
in consequence of the presence of hysteresis. This lost work becomes considerable
when powerful fields are employed and high speeds of rotation. It may become so
large that the heating resulting from it prevents the working of the machine with-
out danger, even without supplying any utilizable current. Efforts have con-
sequently been made to avoid altogether the use of moving iron in the armatures of
dynamos. Various plans have been proposed and realized; we will mention, for
example, the machines with radial armatures of Desroziers and others, and the
original machines of Siemens with a drum like winding, revolving on stationary
magnetic masses. These machines present all the inconveniences of weak and
complicated construction and something like impracticability in the drum winding.
Besides all windings of this sort have the serious inconvenience that neighbouring
sections of the winding have between them the total difference of tension furnished
by the machine. Hence the difficulties of insulation are much augmented; the
interspace and interior resistance are also increased. These armatures to have
anything approaching the requisite strength have to be composed of somewhat stiff
conductors in which Foucault currents limiting the power and the yield are
set up.
We have found that a suitable compromise can be obtained by a mixed system
in which the iron is employed in a very small quantity, just that required for
solidity of construction and arranged in such a manner that the presence of this
iron does not create any appreciable magnetic resistance. The conductors
supported by the iron, may be composed of multiple wires, as fine as may be
desired, so as to avoid Foucault currents.
The sections of winding follow each other regularly as in a Gramme ring
without the inconvenience which drum windings of the Siemens class present,
namely, the presence of neighbouring conductors between which there exists all the
tension difference available at the terminals of the machine.
Figure 1 shows a sectional elevation of our dynamo which we have shown with
six poles but which obviously may be constructed with any even number of poles.
The inductor is composed of two multipolar concentric electric magnets, the
poles of opposite names N. S. in juxta position the one to the other, so that the
magnetic flux created by the exterior magnetic magnet aids in tension to that
A

page_text: furnished by the interior electro magnet. Thus three double magnetic circuits are
formed indicated in Figure 1 by dotted lines c. m. Each magnetic flux twice
traverses radially the thickness of the armature, which is composed of a divided
iron ring the internal and external faces of which are covered with straight
conductors arranged parallel to the axis as in the Gramme armature, but coupled
together in a special manner represented and described further on.
Figure 2 shows a longitudinal section of the machine, illustrating the manner in
which the interior inductor A¹ is attached, as well as the arrangement of the
mounting of the machine upon its axis B. The drum C is fixed' by its base upon a
solid disc C¹ of bronze or other non magnetic or but partially magnetic metal fixed
upon the axis B. The connections to the base of the drum occupy a thickness not
exceeding that of the ring itself so that the armature can be removed from the
inductor without it being necessary to remove this last. A is the exterior inductor
fixed upon the base of the machine. D is the collector fixed upon the axis B.
E and F are the bearings and G the motive pulley.
Figure 3 shows in perspective the drum with the accessories removed and covered
with one section only of winding with a commencement of another, so as to show
the manner in which the conductors are connected the one to the other. The
"drawing represents a commencement of winding in tension. Following the
direction of the arrows starting from the exterior conductor a it is seen that this is
connected by the connection 1 to the interior conductor 6 placed about 60 degrees
"further on, in front of the next pole. In its turn the interior conductor / is
connected by the connection 2 to the external conductor e also placed 60 degrees
further on.
Then in order, c is connected to def g by the connections 3, 4, 5 &c. ;
ġ is the commencement of the following section, and the same is repeated as many
times as there are sections of winding..
Between the neighbouring conductors a and g there exists a difference of tension
equal to the sum of the electro motive forces developed when at work in a b c d e f
"that is to say in one complete section of the winding, as in the Gramme ring and
-not as in the ordinary drum, winding of the Siemens type; it is the same for all the
wires covering the armature.
:
Figure 4 shows the arrangement of the connections upon the bases of the drum
for a machine of six poles. The winding is in tension as in Figure 3 and the
-sections of winding are 13 in number.
Figure 5 shows a quantity winding with 12 sections.
A machine of this sort may be furnished with inductors and armatures of various
forms, for example, the winding may be radial instead of longitudinal without
change of principle but as we cannot describe all the arrangements possible we
limit ourselves' to those above represented.
Finally we claim as our invention a bi or multipolar dynamo electric machine
characterized by (1) A double inductor with poles of opposite names placed in
juxta position the one to the other so that the magnetic flux produced traverses
through and through a ring form armature so that the electro motive forces
developed in the internal conductors may be in the same direction as those delivered
in the external conductors placed between the same poles. (2) An armature com-
posed of a divided drum or ring of iron of reduced thickness supporting two series of
conductors, the one internal, the other external, coupled together in series, so that
the electro motive forces developed in cach of the internal conductors are added to
the electro-motive forces developed in each of the external conductors by means of
connections made upon the bases of the drum or of the ring connecting the
⚫conductors from pole to pole; the whole substantially as described.
7 7
T-1
100
CARPMAEL & Co.,
Agents for the Applicants.