Electric Motors.
Year: 1890

page_text: Date of Application, 6th June, 1890-Accepted, 9th Aug, 1890
COMPLETE SPECIFICATION.
Electric Motors.
I, HENRY GROSWITH, of 1430 Penn Square, in the City of Philadelphia, County
of Philadelphia, State of Pennsylvania, United States of America, Doctor, 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 relates to an improvement in Electric Motors, the object being to
provide such a motor which shall be very efficient in use and possess advantages
over other such machines now in general use.
The invention consists essentially in an electric motor, the field magnets of which
are each composed of primary and secondary cores magnetically connected together
and wound with conducting wires in opposite directions, and electrically united, in
combination with an armature consisting of a series of separate alternately arranged
coils wound in opposite directions, the coils of each series being electrically connected
and each series united with separate commutator plates, substantially as hereinafter
set forth.
The invention also consists in the novel construction and arrangement of parts
bereinafter fully described and specifically defined in the claims.
In the accompanying drawings
Figuro 1 is a vertical sectional view of an electric motor constructed according
to my invention;
Figure 2 is an end view of the same;
Figure 3 is a sectional view of the armature ;
Figure 4 is a diagrammatic view showing the electric circuit through the field
magnets and armature.
In said drawing the reference numeral A designates the armature, and B its shaft,
Cthe poles, D the field magnets, and E the yoke connecting the cores of said
magnets.
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The field magnets are exact duplicates of each other and are constructed as
follows: first take the cylindrical cores F, F, 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 F,
with wires d the windings being in opposite directions, that is to say, one is wound
from right to left while the other is wound from left to right. After a proper
thickness has been attained for the inner or
primary field as I term it, I cover
each magnet thus formed with a coating or jacket of suitable insulating material.
The next step is to form outer or "secondary "cores e, of coiled wire or soft iron of
proper thickness around the cylindrical body of these insulated inner magnets, which
in turn are covered by layers or jackets of insulating material f. The magnets are
now completed by winding said wires d around the secondary cores but in opposite
directions to the windings of the inner coils and then electrically connecting said
primary and secondary wire coils with each other and each pole in series with the
other as per Fig. 4, magnetically connecting all the cores by the yoke E.
From the above description it will be seen that the convolutions of the primary
coil of each field magnet run in a reverse or opposite direction to the convolut ons
of the outer or secondary coil thereof, the inner ends of said wires being united or
connected together while the outer ends constituting the terminals of the secondary
coils are to be connected with battery, and where thus connected, the circuit will be
from battery through outer or secondary coil of one magnet, then in a reverse or
opposite direction through inner or primary coil, then over to inner coil of other

page_text: magnet and from thence in a reverse or opposite direction through outer or secondary
coil of this magnet to battery.
The manner of winding and connecting said coils may be varied, however, without
departing from the spirit of my invention. For instance, a single wire may be used
in building up the field magnets, said wire first being wound upon one of the inner
cores, the secondary core then formed thereupon, then the wire wound in a reverse
direction upon said secondary core, then carried over to the other magnet which is
similarly formed. In this case all the coils are formed of one and the same wire.
Or the coils may be formed of four separate wires which are afterwards connected
ogether, the essential feature being that all the coils shall be composed of a continuous
conductor wound in opposite directions upon the primary and secondary cores
respectively.
Upon the tops of magnets D are placed insulating disks H of vulcanite or other
suitable material which separates them from the under side of the yoke plate E, yet
in such a manner that there shall be magnetic contact or connection between the
central cores F and the yoke and also between the secondary cores e and the yoke.
Similar disks T are placed between the under side of the magnets D and their
respective pole pieces C.
The inner coils of each magnet may be many more than the outer or secondary
coils.
The letter A designates the armature, B its shaft, K the core and L, L, the
commutator plates. These are of usual or ordinary construction except that the
commutator plates are placed on each side of the machine and each is provided with
its own brushes M, M.
The armature coils consist of a number of separate wires alternately wound in
opposite directions upon the core and the terminals of each series of alternate coils
being electrically connected and joined to the commutator plate upon one side of the
machine while the terminals of the other series are similarly united and joined to the
other commutator plate. This forms in effect two distinct armatures having no
electrical connection with each other and the positive brush of one commutator plate
is connected with positive binding post while the other similarly situated or positive
brush of the other commutator is connected with negative post or vice versa according
to the direction in which the motor is running, determined by switch; the negative
brushes one on each commutator connecting with battery see Fig. 4.
From the above it will be seen that the main working current from battery never
goes through both series of armature coils at the same time, which is clearly shown
in the diagram, Figure 4, the arrows showing direction of said current from binding
post through one series of the coils to battery. The shunt current from the field
magnets, after passing therethrough, is carried to the other series of armature coils
and from thence conducted to battery.
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 an electric motor the combination with the field magnets each consisting of
a primary and secondary core wound with conducting wire in reverse or opposite
directions and electrically and magnetically connected or united, of an armature
having separate coils wound in opposite directions and alternately arranged in
connected series, and each series connected with separate commutator plates,
substantially as described.
2. In an electric motor the combination with field magnets each consisting of
primary and secondary cores wound with conducting wires in reverse or opposite
directions and electrically and magnetically connected or united, of an armature
consisting of a shaft, a core, commutator plates and connecting wires wound in opposite
directions forming a series of alternating reversely wound coils, the wires of each
series being electrically connected and joined to one of the commutator plates, while

page_text: the other one similarly united and connected with the other plate, and said commutator
plates provided with positive brushes connected respectively with positive and
negative binding posts and negative brushes connected with battery, substantially as.
described.
FELL & WILDING,
Agents for the Applicant.