armature and induction coils.
Year: 1890

page_text: Date of Application, 18th Oct., 1890-Accepted, 24th Jan., 1891
armature and induction coils.
In the said drawings referring to Figures 1 and 4 inclusive, the reference letter A
designates the armature coil, A₁ the induction coil, B the armature shaft, C the pole
pieces, D the field magnets, and E the yokes connecting the cores of said magnets.
The field magnets are exact duplicates of each other and are constructed as follows.
I first take the cylindrical cores FF having axial bores or apertures for the reception
of the bolts G by which they are connected respectively at opposite ends to the yoke
plate E and pole piece C. Next I wind each of these cores with the wire d until the
proper thickness has been attained, and connect one terminal of said wire with switch
plate band by means of switch lever a connect with dynamo or generator and the
other terminal with the armature brush H¹ connected with return conductor or
wire a, to generator. Around this primary core I next form a secondary core of
soft iron e, of proper thickness and then wind with wire g. The said cores are then
magnetically connected by means of the yoke E. One of the terminals of the wire g
is connected with the other switch plate 61, while the other terminal is connected with
the brush H³ of the induction coil, more fully shown in Figure 4.
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The letter I designates the armature core and K, K, the commutator plates. These
are of the usual construction except that the commutator plates are placed on each
side of the machine and each is provided with its own brushes H, H¹, H², H³.
The armature and induction coils consist of a number of separate wires wound in
opposite directions upon the core and the terminals of each series of alternate coils
being electrically connected and joined to the commutator bars upon one side of the
machine while the terminals of the other series are similarly united and joined to the
other commutator bars.
There are thus formed two sets of separate and distinct coils electrically disconnected
from each other one of which A, forms the armature coil through which the current
from the generator passes to energise it, while the other is an induction coil by which
the currents induced in the armature coil are carried away by brush H2 and by means
of wire g connected with said brush they pass through said wire around the cores of
the field magnets and from thence back through brush H³, thus assisting in energizing
the field magnets whereby their power is increased. The circuit is as follows: From
generator to switch lever a, plate b, wire d, around primary cores of field magnets, to
brush H' and conductor x to generator. Also from plate l, through armature A and
from armature by brush H¹ to conductor x and generator.
At the same time the induced currents from the induction coil flow back through

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brush H2 to wire g, thence around the secondary cores of the field magnets and from
thence back through brush H³ thus materially increasing the effectiveness of the said
magnets as will be apparent.
By shifting switch lever a over to switch plate 6' the direction of the current from
the generator is changed and the operation of the motor reversed, the armature coil A
now becoming the induction coil and vice-versa. The main or motor current now
flows through armature coils A¹ and field wire g and thence to wire a and back to the
generator. From the above it will be seen that I utilize the inductive effects of both
field and motor current in increasing the effect of the field magnets and at the same
time materially reduce the sparking due to self-induction in the armatnre wire.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. In an electric motor the combination of an armature core wound with two sets
of coils, two commutators, brushes, a field magnet having two sets of coils one
terminal of each set being connected to one brush of its respective commutator and
to a common conductor, and the other terminal of each set of field coils being
connected to the other corresponding brush and to a contact or binding post for
external connection.
2. An electric motor having a set of field coils, armature coils, and commutator,
in one circuit, a duplicate set of elements, a commom external connection to one
brush of each cominutator, and a pair of contacts or binding posts connected
respectively to the two other brushes for external connection.
3. The combination with the field magnets and armature of an electric motor, said
armature having separate coils connected respectively to commutators having positive
and negative brushes on opposite sides of the machine, of a switch lever, a conductor
connecting said lever with the positive pole of a source of electricity, the contacts b
and 6 electrically connected respectively with each of the positive brushes of the
commutators, the field magnets having their terminal wires connected with said
positive brushes and the return conductor connected with negative brushes of the
commutators and with the negative pole of the source of electricity, substantially as
described.
Dated this Saventeenth day of Oatahan 1800
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.