Electric Motors.
Year: 1890

page_text: Date of Application, 14th Jan., 1890-Accepted, 15th Feb., 1890
Electric Motors.
I, STANLEY CHARLES CUTHBERT CURRIE, Electrician, a Subject of the Queen of
Great Britain, now residing in Philadelphia, Pennsylvania, U.S.A., do hereby declare
the nature of my invention for ELECTRIC MOTORS, and in what manner the same
is to be performed, to be particularly described and ascertained in and by the following
statement:-
The object of my invention is to increase the efficiency and improve the operation
of electric motors. By my improvements 1 obtain a constant and even torsion, an
equal distribution of forces at all periods of revolution, and avoid dead points. To this
end I employ multiple field poles and cause the changes of polarity in the poles of the
armature to pass from + to neutral and then to -, and vice versa.
In the accompanying drawings-
Figures 1, 2, 3, 4, 5, 6, 7, and 8 are diagram views illustrating different positions of
a motor having sixteen commutator bars, sixteen armature poles and four series of
windings.
Figures 9, 10, 11, and 12, are similar views of a motor having eight commutator
bars and two series of windings.
The machine illustrated comprises two field magnets of three poles each arranged
on opposite sides of a cylindrical armature. On one side the center field magnet is,
say of sign and the two outside ones, and on the opposite side the central pole
is and the outside ones + In other words opposite poles are of unlike polarity.
The armature indicated in the diagram is of a cylindrical toothed type. Each set of
field magnets.consists of one coil A, wound upon the central core, Figure 1, and two
exterior poles a.
-
Referring to figures 1 to 8, the armature is provided with sixteen poles b, and they
are wound throughout with four distinct series or sets of windings, the first set of
windings or that nearest the commutator is connected with commutator bars 1, 5, 9, 13;
the second set is connected with the bars 2, 6, 10, 14; the third set with the
bars 3, 7, 11, and 15; the fourth set with the bars 4, 8, 12, 16. Each winding
comprises a series of coils and each coil envelopes two poles of the armature, adjoining
pairs of poles being wound in different directions, and the wires connected between
coils with their proper commutator. bars. The coils of one winding are opposite the
spaces between the coils of adjacent windings. In other words, the coils of the second
layer or series of windings embrace adjoining cores included in the different coils of
the first winding; The coils of the third winding embrace adjoining cores included
in different coils of the second winding; and the coils of the fourth winding are
similarly related to those of the third. To explain more specifically, starting from
commutator bar number 1 the wire extends in both directions and is coiled in a reverse
sense around adjoining pairs of poles connections being made between coils with the
commutator bars 1, 5, &c. Starting from bar 2 the wire passes between two poles
enveloped by a coil of the first winding, extends in both directions and is wound in a
reverse sense around adjoining pairs of poles, connections being made between the
coils with the bars 2, 6, &c.
When the brushes are on bars connected with the first winding, for instance, upon
bars 1.and 9 in figure 1, the first winding only is in circuit and the polarities of the
armature will be as indicated; that is, the four poles at the top of the armature will
be +; the four poles at the bottom of the armature will be -; and on each side of
the armature the two poles nearest the bottom poles will be +, and the two nearest
the top poles will be When the brushes are upon bars 1 and 2 and 9 and 10,
Fig. 2, the three top poles will be + and then looking to the left in the direction of
-

page_text: -
rotation, the poles will be neutral, minus, neutral, plus, neutral, minus, minus, minus,
neutral, plus, neutral, minus, neutral. The signs + and on the inside of the
windings of course indicate the polarities at the circumference of the armature. In
each case it will be perceived that the polarities are such as to cause the revolution of
the armature with a practically even torsion or strain. In figure
the brushes are
upon bars connected with the second winding; in figure 4 with the second and third
windings; in figure 5 with the third winding, only; in figure 6 with the third and
fourth in figure 7 with the fourth only; and in figure 8 with the fourth and fifth.
From these diagrams it is clear that each pole of the armature in passing from
or becomes first neutral during one portion or stage of the revolution and then of
the opposite polarity. When the brushes throw two windings into action as in
figures 2, 4, 6, and 8, the armature is doubly magnetized at top and bottom between
the field poles, whereas these points directly opposite the poles are neutral and those on
each side between the middle and upper and lower field poles are active, and of a
polarity to be attracted in the direction of rotation. The course of the current in all
the winding is shown by the arrow heads.
I prefer to extend the upper and lower field poles concentrically with the armature
as indicated at y to afford full opportunity for action between these poles and
the armature. Of course this method of winding may be applied to armatures of any
suitable type.
In figures 9, 10, 11 and 12 I have shown the application of my invention to a
motor having eight commutator bars and two sets of winding, each winding being
connected with alternate bars in the commutator. The armature has eight poles and
each pole is wound with a coil of each winding, adjoining coils in each winding being
wound in a reverse sense, and on each pole the coils of the second winding are wound
reversely to those of the first. In figures 10 and 12, where both windings are in
circuit, the upper and lower poles are respectively doubly magnetized minus and
plus, while the intermediate poles are neutral. The polarities in the different positions
of the armature are plainly marked in the drawings which speak for themselves and
more specific description seems unnecessary.
In this form of machine as well as in that shown in other figures of the drawing,
the armature poles either + or are for a portion of a revolution neutral before
becoming of opposite polarity.
-
And now having particularly described and ascertained the nature of this said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is―
1. The combination with opposite sets of field magnet poles, each having a middle
pole of given polarity and outside poles of opposite polarity unlike poles in the two
sets being opposite each other, of an interposed multipolar armature wound with
independent circuits, each winding or circuit consisting of a series of coils, wound
alternately in reverse direction, and the commutator bars and brushes, substantially
as set forth.
2. The combination with opposite sets of field magnet poles each having a middle
pole of given polarity and outside poles of opposite polarity unlike poles in the two
sets of field magnets being opposite each other, of an interposed multipolar armature
having independent windings each connected with its commutator bars, each winding
consisting of a series of coils wound in a reverse sense around adjoining pairs of poles
and each pair of poles included in a coil of one circuit being adjoining poles
included in different coils of another circuit, substantially as set forth.
3. A multipolar armature having multiple windings, each of which is connected
with its commutator bars, and each consisting of a series of coils wound in a reverse
sense around adjoining pairs of poles, and each pair of poles included in a coil of one
winding, being adjoining poles included in different coils of another winding, sub-
stantially as set forth.
4. In an electric motor, the combination with the field-magnets, of the multipolar

page_text: armature, the poles of which are each independently wound in different circuits, and
the commutator with the bars of which armature circuits are connected, substantially
as set forth.
5. In an electric motor the combination, substantially as set forth, of the field
magnets, the multipolar armature having independent windings traversing all the
poles of the armature, each winding consisting of coils alternately reversely wound,
and the commutator with equi-distant bars of which each circuit or winding is
connected in the manner described.
Dated this 21st day of November 1889.
STANLEY CHARLES CUTHBERT CURRIE.