Year: 1887

page_text: Date of Application, 5th Apr., 1887
Complete Left, 4th Jan., 1888
Complete Accepted, 17th Feb.. 1888
I GISBERT KAPP of Stanley Villa Wimbledon in the County of Surrey Electrician
do hereby declare the nature of my Invention to be as follows:-
My Invention consists in improvements in continuous current dynamo electric
machines used as generators or motors and is applicable to such machines as have drum
or cylinder or disc armatures. In machines of the latter type I prefer to construct
the core of the armature partly of soft iron wire and partly of soft iron tape the
latter being comparatively narrow and two tapes being coiled to form the end faces of
the core the iron wire being coiled into the annular trough thus formed, my object in
employing narrow tape and iron wire is to facilitate without undue heating the pene-
tration of the core by magnetic lines of force in other directions than only parallel to
the axis of rotation. The magnetic field of my dynamo electric machine may be
bipolar or multipolar but in all cases I split up the magnetic system into two portions,
one excited by coils in series with and traversed by the armature current or a definite
and constant portion thereof; and the other excited by coils which may be traversed
by a variable portion of the armature current or by a shunt current or by a current
I call the first
from an independent source or by a combination of these methods.
portion of the magnetic system the "normal" field and the second portion the
"auxiliary field. I arrange the pole pieces of the auxiliary field with a certain
angle of advance (in the direction of rotation) over those of the normal field so that
each individual wire on the armature after passing the neutral zone comes under the
influence of the normal pole piece before it conies under that of the auxiliary pole
piece of the same polarity. In this manner I cause the reversal of current in the
wires passing under the brushes to take place in a position where only the normal
field is active and thus variations in the strength of the auxiliary field do not materially
affect, the best position of the brushes for the sparkless or nearly sparkless collection
of the current.
I
may instead of employing only one armature, employ two armatures mounted on
the same spindle and let one revolve in the normal and the other in the auxiliary field
corresponding coils on the two armatures being connected in series and only one
armature having a commutator.
For purposes of regulation I vary the exciting current in the auxiliary field. This

page_text: may be done either by hand or automatically in several well known methods but in
cases where under a variable speed of revolution and variable resistance in the external
circuit the machine is required to furnish a nearly constant current I employ the
following arrangement. The armature normal field, auxiliary field and external
circuit are all coupled in series. If the auxiliary field is of the single horse shoe type
I place across the terminals of its exciting circuit a shunt rheostat and if the field be
of the double horse shoe type I may do the same or I may arrange the rheostat to be
a shunt to the exciting circuit of one horse shoe or set of horse shoes only. The
contact pieces of the rheostat group round an insulated cylinder in a similar
manner as are arranged the sections of the commutator of an ordinary continuous
current dynamo. A brush capable of rotation round the centre line of this commu-
tator serves as movable contact and according to its position which is controlled by a
solenoid or electro-magnet, the amount of current respectively passing through the
shunt rheostat and through the exciting circuit of the auxiliary field is varied. The
solenoid is in circuit with the main current and its force is counterbalanced by an
adjustable weight or spring. The electrical connections are made so that upon an
increase of main current the resistance of the shunt rheostat is diminished and vice
versa.
If the dynamo electric machine is to be used as a motor worked by a constant
current obtain uniformity of speed under varying loads by actuating the rheostat
not by an electro magnetic device, but by a centrifugal governor or other mechanical
speed regulating device. If the dynamo electric machine is required for the
production of variable currents at constant pressure I excite the auxiliary field with a
shunt current and insert the rheostat in series into this exciting circuit. The solenoid
is then inserted as a shunt across the points between which the pressure is to be main-
tained constant and the connections are made so that a rise in pressure produces an
increase in the resistance of the series rheostat.
If the dynamo electric machine is to be used as a motor fed from a constant
pressure circuit I may either make the machine self regulating by winding the
auxiliary field with a shunt and differential main circuit or I may omit the main and
regulate by a centrifugal governor and rheostat in the manner already described with
this difference that the rheostat is in series with the shunt exciting coils; instead of
being a shunt to the series exciting coils as before.
Dated this 5th day of Anril 1887

page_text: Improvements in Dynamo-electric Machinery.
I, GISBERT KAPP of Stanley Villa Wimbledon in the County of Surrey, Electrician,
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 :-
[
My Invention consists in Improvements in Continuous Current Dynamo Electric
Machines used as generators or motors and is applicable to such machines as have
drum, cylinder or disc armatures. In machines of the latter type I prefer to construct
the core of the armature partly of soft iron wire and partly of soft iron tape, the
latter being comparatively narrow and two tapes being coiled to form the end faces of
the core, the iron wire being coiled into the annular trough thus formed. My object
in employing narrow tapes and iron wire is to facilitate without undue heating the
penetration of the core by magnetic lines of force in other directions than those which
are parallel to the axis of rotation. The magnetic field of my dynamo electric
machine may be bipolar or multipolar, but in all cases I split up the magnetic system
into two portions one of which is excited by coils in series with and traversed by the
armature current or a definite and constant portion thereof while the other is excited
by coils which may be traversed by a variable portion of the armature current or by a
current from an independent source or a combination of these methods. I call the
first described portion of the magnetic system the "normal field," and the second
described portion the "auxiliary "field. I arrange the pole pieces of the auxiliary
field a certain distance in advance (in the direction of rotation) of the pole pieces of
the normal field so that each individual wire on the armature after passing the neutral
zone comes under the influence of the normal pole piece before it comes under the
influence of the auxiliary pole piece of the same polarity. In this manner I cause
the reversal of current in the wires passing under the brushes to take place when only
the normal field is active and thus variations in the strength of the auxiliary field do
not materially affect the best position of the brushes for the sparkless or nearly
sparkless collection of the current.
Instead of one I may employ two armatures and mount them both on the same
spindle. One armature will then revolve in the normal and the other in the auxiliary
field. Corresponding coils on the two are connected together in series and one of the
armatures is provided with a commutator.
For purposes of regulation I vary the exciting current in the auxiliary field.
This may be effected either automatically or by hand in several well known
methods, but in cases where under a variable speed of revolution and variable
resistance in the external circuit the machine is required to furnish a nearly
constant current, I employ the following arrangement. The armature normal
field, the auxiliary field, and the external circuit are all coupled in series.
the auxiliary field is of the single horse shoe type, I place a shunt rheostat across
the terminals of the exciting circuit. If the field is of the double horse shoe
type the rheostat may be arranged in the same manner, or it may be arranged as
a shunt in the exciting circuit of one horse shoe or set of horse shoes only. The
If

page_text: contact pieces of the rheostat are grouped around an insulating cylinder in a similar
manner to the sections of the commutator of an ordinary continuous current dynamo.
A brush capable of rotation round this commutator serves as the movable contact and
according to its position which is controlled by a solenoid or an electro-magnet, the
amount of current passing respectively through the rheostat and the exciting circuit
of the auxiliary field is varied. The controlling solenoid or electro-magnet is in circuit
with the main current and is counterbalanced by an adjustable weight or spring. The
connections are made so that as the main current increases the resistance of the shunt
rheostat diminishes and vice versa.
If the dynamo-electric machine is to be used as a motor worked by a constant
current I obtain uniformity of speed under varying load by actuating the rheostat by
a centrifugal governor or other mechanical instead of electro-magnetic device. If the
machine is required for the production of variable current but constant pressure, I
excite the auxiliary field with a shunt current and connect the rheostat in series with
this exciting circuit. The solenoid is then connected as a shunt across the points
between which the pressure is to be maintained constant, so that a rise in pressure
produces an increase in the resistance of the series rheostat.
If the machine is to be used as a motor fed from a constant pressure circuit I may
either make the machine self regulating by winding the auxiliary field with a shunt
and differential main circuit or I may omit the main and regulate by a centrifugal
governor and rheostat in the manner already described, with this difference, that the
rheostat is in series with the shunt exciting coils instead of being a shunt to the series
exciting coils as before.
The appended sheets of drawings illustrate the application of some of my improve-
ments to dynamos and motors.
Fig. 1. illustrates the core of a disc armature constructed according to my Improve-
ments; Fig. 2, is a plan of Fig. 1, and shows the relative positions of the normal and
auxiliary pole pieces as applied to disc machines. In Fig. 1, H H are the sides of
the core formed by coiling soft iron ribbons or bands together with ribbons of some
insulating material upon a suitable support T. Two flanges are thus formed and the
space between is filled with soft iron wire W. Both in this Figure and in Fig. 2,
CC are the magnet cores upon which the field coils are wound in the usual way:
Y Y are the yokes, and N S are the normal and N¹ S' the auxiliary pole pieces. If
the armature rotates in the direction of the arrow shown in Fig. 2, then each coil of
the armature is brought under the influence of the normal pole piece N before it is
brought under the influence of the auxiliary pole piece N¹, and similarly with respect
to pole pieces S and S¹. The brushes should be placed so that the coils short circuited
by them shall occupy a position about midway between the auxiliary pole pieces, or
about the position indicated by the lines B B and B B'. It will be evident that
instead of arranging the auxiliary pole pieces with an angular advance in the direction
of rotation over the normal pole pieces, I can obtain the same effect by placing the two
sets of pole pieces so as to exactly face each other and by winding the armature with
oblique coils the wire on one side of each turn having a certain angular advance over
the wire on the other side of the same convolution.
Figs. 3 and 3 shew how these Improvements may be applied to multipolar cylinder
machines. A is the armature surrounded by two sets of magnets. NS NS together
with a yoke Y form the normal field; and magnets N¹S' N₁S' with yoke Y¹ form the
auxiliary field. For the sake of clearness the sets of magnets are shewn side by side
but it will be understood that in reality they are placed one behind another and enclose
the same armature A.
The lines B B and B¹ B' indicate approximately the positions of those armature
coils which are short circuited by the brushes.
Figs. 4, 4 and 5 shew the arrangement of the normal and auxiliary fields as applied
to a bi-polar drum machine of the single horse shoe type. Fig. 4 is a section of the
auxiliary field along the line 11 of the plan Fig. 5, and Fig. 4" shows the normal field
and in a section along the line 22. As before B B represents the position of the
short circuited coils...

page_text: Figs. 6 6 show a cylinder machine of the double horse shoe type to which my
Improvements are applied. Fig. 6 and 6ª illustrate respectively the auxiliary and
normal fields and are sections along the lines 1 1 and 2 2 of the plan Fig. 7. Similar
letters denote similar parts in Figs. 3 3, 4 4 5, and 6 6" 7.
It will be observed that in Figs. 4 and 6 the pole pieces N₁ and S¹ are symmetrical
while the pole pieces N S in Figs. 4" and 6" are not so. In these cases the armature
is wound in the usual way that is the external wires are parallel to the axis throughout
their length and in order to permit the commutation of current to take place in each
wire whilst under the influence of the normal field only it is necessary to arrange the
auxiliary field with a certain angular advance in the direction of rotation, hence the
difference in the shape of the normal and auxiliary pole pieces. It will however be.
evident that I may employ symmetrical pole pieces for both the normal and
the auxiliary field and that there need be no angular advance of one set of poles
over the other, if the required angular advance is produced in the armature
wires themselves as shewn diagrammatically in Fig. 8. The part A is influenced
by the auxiliary field and the part A is influenced by the normal field. The
part B of each wire has a certain angular advance in the direction of rotation shown by
the arrow over the part B' of the same wire. At the moment of commutation the
part B of each wire is being influenced by the normal field so as to produce sparkless
or nearly sparkless commutation; and the part B is about midway between and
therefore free from the influence of the auxiliary poles.
When a machine constructed by any of the heroin before described methods is to be
used for the production of a nearly constant current through a variable external
resistance and the speed at which the dynamo is driven varies, conditions which
frequently occur in are lighting, I employ the apparatus shewn in Fig. 9 in connection
with a series of resistances to automatically obtain the desired regulation. The
solenoid D is in the main circuit and contains within it a soft iron core I suspended by
a spring E from an adjustable screw T. The solenoid is connected by means of a silk
or other cord with the shaft O which is supported in insulated glass bearings one of
which is shewn in section at P. The cord is wound a few times round the shaft and
is attached at its lower end to a weight or spring F. Attached to a standard Q which
also supports the second insulated glass bearing, is a commutator R constructed in a
similar manner to the commutator of an ordinary dynamo. The projecting ends R¹
of the commutator are connected with different points in the series of artificial
resistance R as shown diagrammatically in Figs. 10 and 11. In Fig. 9 however these
connections are omitted for the sake of greater clearness. Mounted on the shaft O is
an arm provided with a counter weight G and contact spring M. As the shaft is
rotated by the movement of the solenoid core I the contact spring M makes contact
with one or other of the segments of the commutator R. A spring K rubbing
against the shaft O establishes electrical communication between the spring M and the
terminal V.
In Figs. 10 and 11 are shewn the arrangement of circuits and the application of the
governor when the dynamo is respectively of the single and double horse shoe type.
Similar letters denote similar parts in both Figs. A represents the armature commu-
tator, NS the exciting coils of the normal field and R2 the series of artificial resistance.
The pole pieces of the auxiliary field are marked N' S'; the manner of winding the
coils is clearly shewn in the Figs. L represents the external circuit, containing the
arc lamps, motors or other apparatus requiring a constant current. In adapting my
electric governor to motors fed by a constant current, I obtain a constant or
nearly constant speed under varying loads by replacing the solenoid D and core I
by a centrifugal governor or other known speed regulating device, but the other
parts of the governor and the connections, remain the same as shewn in Figs. 9. 10.
and 11.
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 limit myself to the application of my invention to series are lighting

page_text: with a constant current under a varying potential, since it can be applied to glow lamp
lighting, motive power purposes and electro chemical work, and generally in cases
where it is essential to obtain a sparkless or nearly sparkless collection of current whilst
the speed, the current, or the electro motive force may be varied; and I declare that
what I claim is:
(1) In Electro generators and motors, the sub-division of the magnetic field into
two portions of which one in addition to producing a certain fixed minimum of electro
motive force is chiefly instrumental in producing a sparkless or nearly sparkless
commutation and the other is chiefly instrumental in adding more or less electro-
motive force to the said fixed minimuin of electro motive force in accordance with the
varying resistance in the external circuit when the machine is used as a generator and
in accordance with the variations of load when the machine is used as a motor;
substantially as herein before described.
(2) In Electro generators and motors, the combination of the normal and of the
auxiliary magnetic fields with an armature and devices for commutating the current;
substantially as and for the purposes hereinbefore described.
(3) In electro generators and motors having normal and auxiliary magnetic fields
constructing and arranging the corresponding parts of such fields in such a manner
as to produce an angular displacement between the poles; substantially as and for the
purpose hereinbefore described.
an
(4) In electric generators and motors having symmetrical normal and auxiliary fields,
winding or arranging the coils on the armature in such a manner as to produce
angular advance in the armature wires; substantially as herein before described and as
diagrammatically represented by Fig. 8 of the appended drawings.
(5) In electric generators and motors having disc armatures, the construction and
arrangement of the armature core; substantially as and for the purposes hereinbefore
described and as illustrated by Fig. 1 of the accompanying drawings.
(6) The construction and arrangement of the electric governor substantially as and
for the purpose herein before described and illustrated by Fig. 9 of the appended
drawings.
(7) In combination with an electric generator or motor having a normal and an
auxiliary field, an adjustable artificial resistance for varying the exciting current in the
magnetic coils of the auxiliary field.
(8) In combination with an electric generator or motor having a normal and an
auxiliary field an electrical or mechanical governor having a commutator and an
artificial resistance substantially as and for the purpose hereinbefore described.
(9) In electric generators or motors, the combination and arrangement of two
armatures mounted upon one spindle, having their coils joined in series, with one
commutator and with a normal and an auxiliary magnetic field; substantially as
hereinbefore described.
Dated this First day of Januaryv A D 1888