Improvements in Multi-polar Dynamo-electric Machines.
Year: 1890

page_text: Date of Application, 28th Mar., 1890
Complete Specification Left, 27th Dec., 1890-Accepted, 7th Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in Multi-polar Dynamo-electric Machines.
I, GISBERT KAPP of 31 Parliament Street Westminster in the County of
Middlesex, Electrical Engineer, do hereby declare the nature of this invention to
be as follows:-
This invention relates to multi-polar dynamo-electric machines, and these
improvements consist in the construction and arrangement of the armature core
and of the commutator as hereinafter described.
According to these improvements I employ a cylindrical armature core and
arrange the armature circuit on any of the known systems of multi-polar drum
winding, with either series or parallel connections.
The field consists of an even number of magnets placed radially around the
armature and having their outer ends magnetically connected by a common
yoke ring.
The radial depth of the armature core is small as compared with the total radius
of the armature and has such dimensions only as will just suffice to carry the total
flow of lines at a moderate induction.
Instead of building up the core of the armature from complete discs of wrought
iron, I construct it from segments of dises and thus effect a considerable economy
in the amount of material employed. In cutting out the segments I form on their
inner edges two or more lugs which are perforated for the passage of holding bolts.
The positions of these lugs are such that following segments when threaded on the
holding bolts, break joint with each other.
"
In building up the core I first thread upon the holding bolts a complete disc of
stout iron plate provided with corresponding perforated lugs; next, I thread a
number of thin segmental core plates insulated on their surfaces by varnish, paper,
or suitable means until a certain deptlı parallel with the axis is obtained, taking
care to make successive segments break joint. Next, I thread on the bolts a pair
of complete iron discs provided with the perforated lugs on their inner edges and
with projections or "driving horns on their outer edges. These two discs are
separated by means of distance pieces so as to produce an air space between them
for ventilating the armature. I next thread on the holding bolts another series of
the segmental plates and then another pair of complete discs with the air space
between them and so on until the desired length of armature core has been
completed. I make the bolts somewhat longer than the armature core in order
that they may project at each end to a sufficient distance to enable them to be
connected to end rings which may conveniently be castings provided with arms and
with hubs by means of which they may be keyed upon the armature spindle. The
holding bolts thus serve not only to hold the segmental core plates together, but
also to support the armature as a whole.
The core when thus built up may be clamped between the end rings by means of
a second set of bolts or by means of a fast collar and a screw thread and a nut on
the armature spindle.
The commutator is preferably constructed of comparatively large diameter and is
mounted upon a hollow sleeve or pulley having arms and a boss secured upon the
spindle. The objects of this arrangement are, first, to reduce the radial depth of
the commutator sections which with a large diameter for the commutator, would be
excessive; and second, to admit air between the shaft and the body of the com
mutator and to the interior of the armature.
The end connections of the armature conductors are preferably made as described

page_text: in the Specification of Letters Patent granted to me and numbered 9910 of
A.D. 1888.
Dated this 26th day of March A D 1890.
WILLIAM E. HEYS,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Multi-polar Dynamo-electric Machines.
I, GISBERT KAPP of 31 Parliament Street Westminster in the County of
Middlesex, Electrical 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 consists in certain improvements in the construction of multi-polar
dynamo-electric machines, and has more especially reference to the mechanical
arrangement of the armature cores.
According to these improvements the armature core is of cylindrical shape and
the armature circuit is arranged on any of the plans known as multipolar drum
winding, and with either "series" or "parallel" connections.
The field consists of an even number of magnets placed radially around the
armature with their axes either parallel with or at right angles to, the centre line
of the spindle, and having their outer ends connected by a common yoke-ring of
circular or polygonal shape. The magnet cores and the yoke ring may conveniently
be made of cast iron in one piece, or the casting may be constructed with a horizontal
joint in the yoke-ring so that the upper half of the field-magnet system may be
lifted to give access to the armature.
The radial depth of the armature core is small in comparison with its diameter,
being made of such dimensions as will just suffice to carry the total flow of lines of
force at a moderate induction.
It has hitherto been customary to build up the armature core with complete discs
of thin wrought iron, but in the machines made according to my present invention
I do not employ complete discs, but segments of discs, by which means a considerable
waste of material in cutting out is avoided. I may thus employ four quarter circle
segments or other number of segments constituting a complete circle to form one
disc. Each segment is provided with two or more lugs on its inner side, and these
lugs are perforated to admit bolts which hold all the segments together. The
positions of the lugs on the segments are such that successive segments threaded on
the bolts break joint with each other.
In building up the armature core, I thread upon the bolts, first, a continuous ring
or disc of stout iron plate; next, I thread thereon a number of thin segmental core
plates insulated from each other by varnish, paper, or other suitable means, until a
certain depth measured parallel with the spindle is reached. I next thread upon
the bolts a pair of continuous stout iron discs which are also provided with lugs on
the inner side and with tooth like projections or driving horns on their outer
diameters. These two discs are separated by distance pieces so as to form an air
space between them for the ventilation and cooling of the armature. Instead of
the pair of discs with the air space between them I may employ a corresponding
single disc of gun-metal or of other suitable non-magnetic metal. I next thread
upon the bolts a second series of the segmental plates as herein before described,
then another thick disc or pair of discs, and so on until the desired length of
armature core has been built. The bolts employed are of greater length than the
armature core, so that they may project for a sufficient length at each end for
making the attachment to end rings which may conveniently be iron castings
provided with arms and hubs by means of which they may be keyed upon the
spindle or armature shaft. The bolts therefore serve not only for holding the
segmental core plates together, but also for supporting the armature as a whole. I

page_text: clamp the complete core between the end rings of metal, using for this purpose
either a second set of bolts or a collar and a screw-thread and nut upon the
armature shaft.
I prefer to make the end connections between the armature conductors in the
manner and by the means described in the Specification of Letters Patent granted
to me No. 9910 dated the 7th day of July A.D. 1888.
I have appended hereto a sheet of drawings which illustrate in what manner my
invention may be carried into practical effect. In each of the figures thereon
similar parts or details of construction are denoted by similar letters by which they
are hereinafter referred to.
Figure 1 is a diagrammatic representation of a multipolar dynamo machine of
the type to which my improvements are applicable. The armature core is indicated
by two concentric circles but, for the sake of clearness, the segmental division of
the core plates is not shewn.
Figure 2 represents one of the segmental core plates of the armature. These
core plates break joint with each other as represented by Figure 3. The segments
are connected by the bolts P.
Figure 4 is a section along the line A-B of Figure 3 and shews on a larger
scale a portion of the soft iron plates, the bolts P, and the driving disc D with the
driving horns H.
Figure 5 is an elevation of a part of a driving disc shewing the lugs perforated
for the passage of the bolts P, and the driving horns H. This figure also shews
in what manner the driving disc may be made lighter by forming openings O
therein.
Figure 6 is a longitudinal section through a complete armature, the upper part
of the section being taken through one of the bolts P, and the lower part through
one of the bolts Q by means of which the end castings R R may be drawn together
so as to secure between them the armature core.
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 the armature of a multipolar dynamo machine, segmental core plates arranged
to break joint with each other and furnished on their inner peripheries with
perforated lugs for the passage of holding bolts; substantially as hereinbefore
described and as illustrated by the accompanying drawings.
2. In the armature of a multipolar dynamo machine, the combination with
segmental core plates such as those referred to in the preceding claiming clause, of
driving discs or rings having perforated lugs formed upon their inner peripheries for
the passage of the holding bolts; substantially as hereinbefore described and as
illustrated by the accompanying drawings.
3. In the armature of a multipolar dynamo machine, the combination and arrange-
ment of the segmental core plates, the driving discs, and the end rings, secured
together as and by the means set forth; substantially as hereinbefore described
and as illustrated by the accompanying drawings.
4. An armature core for a multipolar dynamo, constructed and arranged sub-
stantially as herein before described and as illustrated by the accompanying
drawings.
Dated this 23rd day of December A.D. 1890.
WILLIAM E. HEYS,
Agent for the Applicant.