Year: 1886

page_text: Date of Application, 29th Dec., 1886.
Complete Left, 23rd Aug., 1887.
Complete Accepted, 27th Sept., 1887
I GISBERT KAPP of Stanley Villa, Stanley Road, Wimbledon, in the County of Surrey,
Electrical Engineer, do hereby declare the nature of this invention to be as follows:-
:―
I will first describe the general arrangement in connection with alternating current
dynamo electric machines and then as regards mechanical details and finally as applied
to continuous current dynamo electric machines.
I employ an armature consisting of a ring support and attachment to the spindle an
iron core suitably subdivided and coils of copper wire in which the currents are
generated. I use a core of comparatively large diameter and small axial length.
The field consists of an even number of steel magnets or electro magnets of alternating
polarity set with their axes parallel to the spindle evenly around the circumference of
the disc and preferably to both sides of it. The ends of each set of magnets farthest
from the disc are magnetically connected by yokes. The pole pieces may either be
carried across the disc so as to surround it on the two faces and on the outer
periphery, in which case each pole piece serves for two magnets, which construction I
hereafter call "surrounding poles; or the pole pieces need not be carried across the
periphery but may abut against the face of the disc in which case each pole piece
serves for one magnet and this construction I call "divided poles."
I wind the core of the armature with as many distinct coils as there are poles and
1 place the coils at even distances from each other. The winding is at right angles
to the face of the disc. I join these coils either in series or in parallel or in any
suitable combination of series and parallel connection amongst each other and with
contact rings fixed to but insulated from the spindle and I take off the currents by
31

page_text: springs sliding on these contact rings. The methods of connection will be obvious to
any competent electrician and need here no special description. I find it is
advantageous to make the width of the pole pieces, measured circunferentially
somewhat smaller than the distance between the edges of neighbouring pole pieces
and to make the width of each coil, also measured circumferentially, about equal to
the space between successive coils. Hence only about one-half the armature core is
covered by the set of coils, the other half being free of winding. The spaces thus
left free may be utilized by winding another set of coils in between the first set and
connecting the respective coils of the second set and with two contact rings and
springs thereby forming a second armature circuit independently of the first one.
In
this way the output of the armature is greatly increased and the machine rendered
capable of feeding two external circuits independently and if required at different
pressures. For example all the coils of one arinature circuit can be coupled in series
and the currents collected from the corresponding pair of contact rings for lighting
a number of arc lamps in series, whilst I can at the same time couple all the coils of
the second armature circuit in parallel and use the currents collected from the
corresponding pair of contact rings for feeding a number of glow lamps in parallel.
Or I can connect the coils of both circuits similarly and obtain currents of equal
strength and pressure in the two independent external circuits. The advantage of so
increasing the output from a given armature by winding it with two circuits would
however not be realized if I were to connect them both to one and the same external
circuit because the impressed electro-motive force in one of the arinature circuits is a
maximum at the moment at which the impressed electro-motive force in the other is
zero. This is due to the difference in phase between the two armature circuits, which
difference is equal to the time required for an angular displacement of the armature
equal to half the angular distance of two succeeding poles. If it be desired to do all
the work in one external circuit only, arrange the machine as follows. Let A
represent one of the armature circuits and let B represent the other. I join the
circuit B with the external circuit and insert in it (in series) the secondary spiral
of a transformer. The primary spiral of this transformer I connect with the armature
circuit A in such way that the induced E.M.F. in the secondary spiral is added to
the impressed E.M.F. of the armature circuit B, whilst the counter E.M.F.
developed in the primary spiral opposes the impressed E.M.F. in the armature
circuit A. In this manner the major portion of the work done by the circuit A is
transferred to the circuit B and therefore also to the external circuit. I excite
the field electro magnets of my alternating current dynamo either from
independent source of electricity producing a continuous current, or I mount a second
armature wound for continuous currents on the spindle of the machine and fit a pair
of separate field magnets, in which case the output of the main armature can be
regulated automatically or by band by the expedient of suitably varying the exciting
power on the separate pair of field magnets, or 1 wind a separate exciting coil on the
main armature, (omitting for this purpose if necessary one or more of the coils in
which the alternating working currents are produced) and connect it with the field
magnets coils by means of a suitable commutator and brushes. To regulate
the strength of the field magnets and therefore the output of the armature.
I sometimes insert into the exciting circuit between the exciting coil on the
armature and the commutator, the secondary spiral of a transformer, the primary
spiral of which is suitably connected with one or more of the other armature coils, or
with any other portion of the main circuit.
an
An arrangement of this kind can at constant speed of rotation be made to a certain
extent self regulating either for constant current or constant pressure without the
employment of any mechanical device, or regulation may be obtained even at variable
speed of rotation by adding a mechanical device which acts upon the iron core of the
transformer and so varies the induced electromotive force in the secondary spiral.
If desirable I connect this mechanical device with the brushes so as to shift their
position and keep them automatically at or near the point of least sparking.

page_text: In some cases I find it advisable to omit the exciting coil on the armature altogether
and obtain the exciting current solely from the secondary spiral of a transformer
combined with a commutator and brushes for changing the alternating current given
off by the secondary spiral into a continuous current suitable for energizing the field
magnets.
The commutator in this and the preceding arrangement is mounted on the spindle
of the armature and consists of as many segments as there are poles in the field.
Alternate segments are in metallic connection, but are insulated from neighbouring
segments and from the spindle. The brushes are placed at an angular distance about
equal to that of two succeeding poles in the field.
I find it economical to form the mechanical support of my armature core of a meta!
ring, spokes and central hub cast in one piece, but this may be varied. The external
surface of the ring is turned to a true cylinder and upon this I coil a flat ribbon of
soft iron with suitable insulation between successive spirals. If the machine is to be
provided with "divided poles" I coil the ribbon until the full radial depth desired is
reached. Over the ring thus formed I place a metal hoop, either continuous or in
segments, and I form radial holes through hoop, armature core and metal ring for the
reception of bolts or fastenings by which the whole structure is firmly held together.
Care should be taken to form the holes midway of the sides through the core so as to
avoid eddy currents and heating. The hoop or each segment of the hoop is provided
with projections on either side which serve as guides during the winding of the copper
coils and also to transmit the power direct to the coils. The projections may be either
cast or formed in one with the hoop, or they may be formed by employing a hoop
somewhat wider than the core cut down to its width in places where the coils are to
be wound, whilst portions of the strips thus separated from the main surface are bent
to a radial position and thus form projections for the support of the coils. For
security against centrifugal force the core thus formed can be provided with a
serving of metal wire on its cylindrical surface before the copper coils are wound on
it. If the machine is to be provided with "surrounding poles" there will be lines of
magnetic force entering and leaving the core on its periphery as well as on its two
faces and in this case the outer portions of the core would be heated by eddy currents
if the core were wound to its whole depth with flat iron ribbon. To overcome this
difficulty I wind the core with ribbon to less than its full radial depth; then I put on
the hoop with its projections turned radially outwards, secure the whole by countersunk
bolts or rivets as already described and complete the winding of the core by layers of
iron wire until the full radial depth is reached. In this case the projections serve not
only for the support of the copper coils, but also as guides during the winding of the
iron wire. The radial depth of this winding should not be less than half the width of
the armature core. Before winding the copper coils on the core thus formed the
whole of it including the projections must be suitably insulated.
In adapting the latter portions of these improvements here described to disc
machines for continuous currents the number of projections will preferably be made
greater than in the case of disc machines for alternating currents.
Dated the 29th day of December 1886.
WM. BROOKES & SON,
55 & 56, Chancery Lane, London,
Agents for the Applicant.

page_text: I GISBERT KAPP of Stanley Villa, Stanley Road, Wimbledon, in the County of
Surrey, 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 :-
I will first describe the general arrangement in connection with alternating current
dynamo electric machines and then as regards mechanical details, and finally as applied
to continuous current dynamo electric machines.
I employ an armature consisting of a ring support and attachment to the spindle,
an iron core suitably sub-divided and coils of copper wire in which the currents are
generated. I use a core of comparatively large diameter and small axial length.
The field consists of an even number of steel magnets or electro magnets of alternating
polarity set with their axes parallel to the spindle evenly around the circumference of
the disc and preferably to both sides of it. The ends of each set of magnets farthest
from the disc are magnetically connected by yokes. The pole pieces may either be
carried across the disc so as to surround it on the two faces and on the outer periphery,
in which case each pole piece serves for two magnets, which construction I hereafter
call "surrounding poles ; or the pole pieces need not be carried across the periphery
but may abut against the face of the disc in which case each pole piece serves for one
magnet and this construction I call "divided poles."
I wind the core of the armature with as many distinct coils as there are poles and
I place the coils at even distances from each other. The winding is at right angles to
the face of the disc. I join these coils either in series or in parallel or in any suitable
combination of series and parallel connection amongst each other and with contact
rings fixed to but insulated from the spindle and I take off the currents by springs
sliding on these contact rings. The methods of connection will be obvious to any
competent electrician and need here no special description.
I find it is advantageous to make the width of the pole pieces, measured circum-
ferentially, somewhat smaller than the mean distance between the edges of neighbouring
pole pieces and to make the width of each coil, also measured circumferentially, about
equal to the space between successive coils. Hence only about one half the armature
core is covered by the set of coils, the other half being free of winding. The spaces

page_text: thus left free may be utilized by winding another set of coils in between the first set
and connecting the respective coils of the second set with each other and with two
contact rings and springs thereby forming a second armature circuit independently of
the first one. In this way the output of the armature is greatly increased and the
machine rendered capable of feeding two external circuits independently and if required
at different pressures.
1 excite the field electro magnets of my alternating current dynamo either from an
independent source of electricity producing a continuous current, or I mount a second
armature wound for continuous currents on the spindle of the machine and fit a pair
of separate field magnets, in which case the output of the main armature can be
regulated automatically or by hand by the expedient of suitably varying the exciting
power on the separate pair of field magnets, or I wind a separate exciting coil on the
main armature, (omitting for this purpose if necessary one or more of the coils in
which the alternating working currents are produced) and connect it with the field
magnets coils by means of a suitable commutator and brushes.
I find it economical to form the mechanical support of my arinature core of a metal
ring, spokes and central hub cast in one piece but this may be varied.
The external surface of the ring is turned to a true cylinder and upon this I coil a
flat ribbon of soft iron with suitable insulation between successive spirals. If the
machine is to be provided with "divided poles" I coil the ribbon until the full radial
depth desired is reached. Over the ring thus formed I place a metal hoop, either
continuous or in segments, and I forin radial holes through hoop, armature core and
metal ring for the reception of bolts or fastenings by which the whole structure is
firmly held together. Care should be taken to form the holes midway of the sides
through the core so as to avoid eddy currents and heating.
The hoop or each segment of the hoop is provided with projections on either side
which serve as guides during the winding of the copper coils and also to transmit the
power direct to these coils. The projections may be either cast or formed in one with
the hoop, or they may be formed by employing a hoop somewhat wider than the core
cut down in the places where the coils are to be wound, whilst portions of the strips
thus separated from the main surface are bent to a radial position and thus form
projections for the support of the coils. For security against centrifugal force the
core thus formed can be provided with, a serving of metal wire over its cylindrical
surface before the copper coils are wound on it.
If the machine is to be provided with "surrounding poles" there will be lines of
magnetic force entering and leaving the core on its periphery as well as on its two
faces and in this case the outer portions of the core would be heated by eddy currents
if the core were wound to its whole depth with flat iron ribbon. To overcome this
difficulty I wind the core with ribbon to less than its full radial depth; then I put on
the hoop with its projections turned radially outwards, secure the whole by counter-
sunk bolts or rivets as already described and complete the winding of the core by
layers of iron wire until the full radial depth is reached. In this case the projections
serve not only for the support of the copper coils, but also as guides during the
winding of the iron wire. The radial depth of this winding should not be less than
half the width of the armature core.
Before winding the copper coils on the core thus formed the whole of it, including
the projections, must be suitably insulated.
In adapting the latter portions of these improvements here described to disc machines
for continuous currents the number of projections will preferably be made greater
than in the case of disc machines for alternating currents.
In the accompanying drawings Figures 1 and 2 respectively show a longitudinal
and transverse section of part of my machine as constructed with "divided" poles,
Figures 3 and 4 show similar sections of my machine as constructed with
"surrounding" poles. S is the armature spindle R the metal ring cast in one with
its arms and hub, Cin Figures 1 and 2 indicates the armature core composed of coiled
iron ribbon with insulation between successive spirals in Figures 3 and 4 is that

page_text: part of the armature core which is composed of coiled iron ribbon and C² is that part
which is composed of iron wire, M M are in all these four views magnet cores upon
which are placed the exciting coils (not shown); Y. Y. are the yokes and P. P the
pole pieces.
Figure 5 is a section through the armature of Figure 1 drawn to a larger scale and
Figure 6 is an elevation of part of the armature. In Figure 5 the different layers of
iron ribbon are indicated by horizontal lines; the distance between the lines must
however not necessarily be taken to represent exactly the thickness of the ribbon
employed as this thickness may vary in different machines. In Figure 6 the different
layers of the coiled ribbon have been omitted to avoid complication of the drawing.
D. D represents the metal hoop which is fastened by means of bolts B. B or equivalent
means of fastening may be used as will readily be understood, these bolts passing
through the armature core C and supporting ring R and being countersunk and
revitted in the latter.
Figure 7 shows a part of this metal hoop straightened out.
For small machines the hoop may conveniently be cut from a piece of sheet metal
to shape such as shown in Figure 7. The projections E. E. must be bent in so as to
point to the spindle as shown in Figure 6 when the hoop is put on the core. Figure 8
is a similar view to Figure 7 the part a, b of each projection having been bent
inwards on the dotted lines.
In Figure 5 the insulation is represented by a thick black line surrounding the
core and serving to insulate the armature coils A from the core and hoop and also to
insulate the projections E from the core. In Figures 7 and 8 the width of the
armature core is indicated by the dotted lines and the clear distance between the
projections E is slightly greater than this width so as to allow room for the insertion
of some insulating material. In Figure 6 the armature coils A A are shown adjacent
to but not touching the projections E, the interval left being provided for insertion of
insulating material.
66
Figure 9 is a cross section through the armature according to the arrangement
shown in Figure 3 and which construction I have already referred to as surrounding
poles."
Figure 10 is an elevation of a part of the armature, Figure 11 is a view of a section
of the hoop and Figure 12 is a section on line I-II of Figure 10 showing the
projections E. E in section. C₁ is that portion of the core which is composed of coiled
iron ribbon as indicated by the horizontal lines in Figure 9 and is the portion
composed of coiled iron wire as indicated by the horizontal and vertical cross lines in
the same view. In Figure 10 the different layers of ribbon and wire have not been
separately indicated in the drawing to avoid complication. The metal hoop may be in
one continuous length as in the previous arrangement, or it may be formed in sections
as indicated by Figure 11. The latter construction I find particularly convenient for
larger machines in which cases the sections of hoop with their projections may be
castings of the form shewn in Figure 11, each casting being fastened by rivets or
bolts BB. or like fastenings as already explained. The thick black lines in Figure 9
and in Figure 12 represent the insulation of the core, a portion of which insulation
serves to separate the projections E from the core. These projections E serve the
double purpose of forming a lateral support for the iron wire core and for transmitting
the power in a positive and mechanical way to the armature coils A.
In large machines where the projections are long I sometimes strengthen them by
filling in the trapezoidal space between two neighbouring projections with fibre or
hard wood or other suitable insulating material indicated at F fastened by means of
rivets or fastenings to the sheet of insulating material between the projections and
the armature core, but other methods of fastening may be used.
Having now particularly described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I wish it to be understood that I
do not claim the use of a disc armature in combination with either divided or

page_text: surrounding poles whether for alternating or continuous current machines or
the use of iron tape and iron wire separately considered, but I declare that what
I claim is :-
In a dynamo electric machine
1. The combination of a disc armature core composed of iron ribbon with a
surrounding metal hoop (as D) having projections (as E) and the whole being
fastened together by bolts or similar fastenings (as B).
2. The hereinbefore described method of making the said hoop by cutting out or
similarly forming sheet metal and bending projecting portions thereof as and for the
purpose set forth.
3. The combination or arrangement and use in armature cores of iron ribbon
to form one part of said cores and iron wire to form the other part thereof with
a hoop or hoops (as D) separating the ribbon and wire portions, and with con-
necting bolts or equivalent fastenings, said hoop having projecting portions serving
as lateral supports to the iron wire and for transmitting the driving force to the
armature coils.
,
WM. BROOKES & SON,
55 & 56, Chancery Lane, London,
Agents for the Applicant.