Improvements in Electric Motors.
Year: 1886

page_text: Improvements in Electric Motors.
I, NATHAN HUNTLEY EDGERTON, residing at the corner of, 13th and Market Streets,
in the City of Philadelphia, County of Philadelphia, and State of Pennsylvania in the
United States of America, 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 has relation to electric motors of the form having a field of force
provided with radially converging magnets and an armature having on its periphery
radially diverging magnets; and it has for its object to simplify the construction and
enhance the durability of the motor, and this I accomplish by providing the field with
two oppositely located pole-pieces each of which preferably form a common or a single
pole-piece for a set or series of magnets or helices, that is to say each pole piece is
provided with a series or set of magnets, and by also providing a simple and easily
constructed & economical form of armature which is so constructed that sparking at
the commutator is avoided, a greater proportionate amount of wire is wound upon or
used for the magnets and heating of the armature is materially reduced where by it is
rendered exceedingly durable and efficient and is adapted for use with any form of
motor having any known or desired form of field of force.
My invention accordingly consists: 1st. Of a field of force composed of a cylinder
or ring having attached to its inner side or bore two oppositely located pole pieces one
or both of which are provided with one or more sets of magnets or helices to provide
pole pieces each of which is common to its own series of magnets or only one of said
poles is common to a series of magnets and the other is without magnets or helices.
2nd. Of a tubular motor casing having one or more sets or series or removable
magnets and core pieces common to each said set of magnets.
3rd. Of a tubular casing having in its bore two oppositely located pole-picces,
outside feet or supports, and detachable end caps having bearings for the armature

page_text: shaft; and, 4th. Of an armature composed of an elongated sleeve or hub of any suitable
prismatic or other configuration in cross-section having radially arranged magnets
arranged lengthwise of the core or parallel to the armature shaft. Each magnet is
composed of a core-piece terminating in a pole piece cast integral with the armature-
hub or sleeve and is wrapped with a helix of wire, so that, while all the magnets have
core-pieces and poles common to an armature hub or sleeve yet the helix of each
magnet is independent of all the others.
At one end of the armature is an insulated ring and at the other end a commutator
composed of insulated blocks, spirally or angularly arranged around the armature shaft.
One set of ends of one polarity of the magnet-helices are connected to or are in
circuit with said insulated ring and the other set of ends of one but opposite polarity
are connected to the commutator, each of the last named ends being connected to a
separate commutator block; one brush may be employed for the commutator and one
for the insulated ring, and the circuit connections between the brushes and the field so
made that the field and armature magnets are in series with the outside or working
current, or, the two brushes may be upon the commutator to place the armature and
field in series with the outside circuit while the one set of ends of the armature magnet
helices connected to the insulated ring, are in multiple are circuit, or, when two
brushes are used upon the commutator the field may be in a shunt circuit.
Reference being had to the accompanying drawings on which; Figure, 1, is an
elevation, and figure, 2, a longitudinal section of an electric motor embodying my
improvements; figure, 3, a cross section, figure, 4, an end view of same; figure, 5, a
perspective of the armature and figure, 6, a partial end view showing usual form of
brushes for the commutator.
A, represents a cylinder or ring which is formed in one piece having outside feet or
supporting ledges, a, removable end plates or caps, B, having central hubs, b, for an
armature shaft, c, To the inner side of the cylinder are affixed by means of screws, d,
two series or sets of radially converging electro-magnets, D, which run lengthwise of
the cylinder. The magnet of each set or series are united by semi-circular pole picces,
E?E? which oppose each other. These pole pieces of the field of force therefore,
are common to two or more magnets radially converging within the cylinder so that
both poles of the field of force have exciting helices.
The heads of the screws, d, are outside of cylinder so that by removing one of the
end plates, B, and withdrawing the screws d, of a set of magnets, D, they are readily
detached and withdrawn from the cylinder for repairs or other purposes without
necessitating removal of the armature. The casing or cylinder being in one piece and
outside of the magnets it rapidly dissipates or radiates into the air heat generated in
the field magnets and they are therefore kept cool and their efficiency is thereby duly
maintained. The armature, C, is composed of an elongated hub or sleeve, c', on shaft, c,
which hub is preferably of a prismatic form in cross section to divide its periphery into
surfaces or sides, c², from each of which project a radial core piece terminating in a
web or plate, e, forming a pole piece between the underside of which and the adjacent.
side, c, of the armature sleeve is wound a helix, c.
The outer surface or side of core pieces, c³, is curved to conform to the curve of the
field pole-pieces adjacent to which the armature pole pieces revolve. As the sides, c²,
of the armature are parallel to the underside of the pole pieces, ct, a uniform and an
increased space between said sides and pole pieces is provided for the helices, c³,
and they are thereby readily wound upon the core pieces, c³, and a proportionately
larger amount of wire may be wound upon the cores to increase the efficiency of the
armature.
The core pieces with their poles, c', and helices, constitute the armature magnets, F,
which are radially arranged around the periphery of the armature sleeve or hub;
while all the magnets are common to the armature, yet the helix of each magnet, it
will be noted, is separate from all the others, that is to say, that no.part of the helix of
one magnet is wrapped upon or is in contact with any of the helices of the remaining
magnets. Any number of these radially arranged magnets may be used.

page_text: In the drawings, I have shown the armature having three. The number of sides, c²,
on the armature varies according to the number of magnets, F, used, but as it is not
essential that the armature sleeve or hub should be of a prismatic form in cross-section,
I do not limit myself thereto as any other suitable configuration of same may be
employed, so long as the feature of separate magnet helices for the armature is
maintained. Upon the shaft, c, at one end of the armature is an insulated ring, G,
and at the other end is a commutator, H, which is composed of insulated blocks, N,
one for each magnet, F, and are spirally or angularly arranged around the shaft so
that the brushes in contact therewith will not break contact with one block before
making contact with a succeeding or another block, that is to say, that the circuit or
current is not broken as the blocks of the commutator revolve past the brushes to
effect the necessary changes of polarity in the armature; hence sparking between the
commutator blocks and the brushes is avoided and the efficiency of the armature is
proportionately enhanced by reason of there being no sparking on the commutator.
The ends, f, of the helices of all the magnets, F, are connected or in circuit with the
insulated ring, G, these ends being all of a like polarity, and the ends, f1, are connected
to the commutator blocks, these ends being all of one but, opposite polarity. All the
magnets therefore, have one set of ends of one polarity connected to the insulated
ring, G, while the other set of ends of one but opposite polarity are in circuit with the
commutator. The brushes, k, for the commutator are mounted on adjustable holders, K,
supported upon plates or brackets, fitting into sockets or recesses, a¹³, in the edge of
the cylinder and screwed thereto so as to be removable, or if desired the brushes or
their supports may be otherwise arranged. The holders, K, have elongated slots, k2,
through which the adjusting screws pass and which secure the holders to plates, K¹.
The commutator may have two brushes as shown in fig. 6, or it may have only one
in which case a brush is placed upon the insulated ring, G.
The field and armature may be in series relation with each other and with the
outside circuit, or the field may be in a shunt relation with the armature or other
desired arrangement of circuit connections may be employed; as I do not limit myself
to any one arrangement of circuit connections for the field armature and outside
circuit. If desired oscillating forked or bifurcated brushes may be used for both the
commutator, H, and, ring, G, as illustrated in figure, 4.
As the form of brushes for the commutator and for the ring and the use of the
brushes upon one or the other of said parts depend upon the internal and external
circuit connections, I do not confine myself to any particular form and arrangement
of the brushes. If desired only one pole piece, E¹, may be provided with helices or
magnets, D, as indicated in full lines in figure, 3, in which case the pole, E¹, without
helices is preferably integral with casing, A, as shown, and hence my invention
embraces either one pole without helices or magnets or both poles having a set or
series of magnets or helices.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed I declare that what I claim is :-
1. In combination with a cylinder having on its inner side radially converging
magnets, opposing pole pieces each common to two or more magnets and an armature
having a series of radially arranged magnets the helices of which are independent of
each other an insulated ring at one end of the armature and a commutator at the other
end, one set of ends of the helices of one polarity connected to the insulated ring and
the other set of one but opposite polarity, connected to the commutator, substantially
as set forth.
2. In combination with a cylinder, having removable end caps provided with
armature shaft bearings, and having on its inner side two sets of radially converging
magnets each set having a pole piece common to all the magnets of a set, of an
armature having a series of radially arranged magnets the helices of which are
independent of each other, an insulated ring at one end of the armature and a com-
mutator at the other end, one set of ends of the helices of one polarity connected

page_text: to the insulating ring and the other set of one but opposite polarity connected to
'the commutator, substantially as set forth.
3. In combination with a cylinder, having removable end caps provided with
armature shaft bearings, and having on its inner side two sets of radially converging
magnets each set having a pole piece common to all the magnets of the set, of an
armature having radially arranged magnets, F, an insulated ring at one end, a com-
mutator at the opposite end composed of spirally arranged insulated blocks, one set of
the ends of one polarity of the magnet helices being connected to said insulated ring
and the other set of ends of one but opposite polarity connected to the commutator,
substantially as set forth.
4. In combination with a cylinder having removable end caps provided with armature
shaft bearings, and having on its inner side two sets of radially converging magnets
each set having a pole piece common to all the magnets of the set, of an armature
having a series of spools wound with helices or coils laid parallel to the axis of the
armature shaft and located upon its periphery, a commutator at one extremity of the
armature and, having same number of spirally arranged segments as there are spools
upon the armature shaft, an insulated ring at the opposite extremity of the armature,
one set of the ends of one polarity of said coils being connected to the commutator
segments and the other set of ends of one, but opposite polarity being connected to
the insulated ring and brushes, fields and circuit connections, substantially as set forth.
5. An armature having a series of radially arranged magnets the helices of which
are independent of each other, an insulated ring at one end of the armature and a
commutator at the other end, one set of ends of the helices of one polarity connected
to the insulated ring and the other set of one but opposite polarity connected to the
commutator, substantially as set forth.
6. An armature having radially arranged magnets, F, an insulated ring at one end,
a commutator at the opposite end composed of spirally arranged insulated blocks, one
set of the ends of one polarity of the magnet helices being connected to said
insulated ring and the other set of ends of one, but opposite polarity connected to the
commutator, substantially as set forth.
7. An armature having magnets, F, an insulated ring at one end having a contact
brush, a commutator at the other end having a brush, one set of the ends of the
magnet helices in circuit with the insulated ring, and the other set in circuit with the
commutator, a field and circuit connections for placing the field and armature in
series relation with the outside circuit, substantially as shown and described.
8. An armature having a series of spools wound with helices or coils laid parallel to
the axis of the armature shaft and located upon its periphery, a commutator at one
extremity of the armature and, having same number of spirally arranged segments as
there are spools upon the armature shaft, an insulated ring at the opposite extremity
of the armature, one set of ends of one polarity of said coils being connected to the
commutator segments and the other set of ends of one, but opposite polarity being
.connected to the insulated ring and brushes, fields and circuit connections, substantially
as set forth.
9. In an electric motor, an elongated casing having in its bore and on one side a
pole piece without helices and on the opposite side another pole piece provided with a
helix or helices and the casing serving as an unbroken or unjointed connecting yoke
for the said pole pieces, substantially as shown and described.
10. In an electric motor, a tubular casing having in its bore on one side, a projection
forming a pole piece without helices and integral with the casing, and on the opposite
side another pole piece detachable from the casing and provided with a helix or helices,
and the casing serving as an unbroken or unjointed connecting yoke for the pole
pieces, substantially as shown and described.
11. An electric motor casing, composed of a tubular body having outside feet or
supports oppositely located pole pieces in its bore and detachable end caps or plates
having bearings for the armature shaft, substantially as shown and described.
12. A motor having a field magnet one pole of which is without helices, an armature

page_text: having spools or helices each complete in itself, an insulated ring on the armature
shaft in multiple arc circuit with one set of the ends of the armature coils and
commutator for the remaining set of ends of the armature coils, substantially as shown
and described.
13. In an electric motor, the combination of an armature having an insulated ring
in multiple arc circuit with one set of ends of the armature coils or helices, and a
commutator having a single forked or one double ended brush, substantially as shown
and described.
14. In an electric motor, the combination of a field magnet having two oppositely
placed pole pieces, a series of helices on one of the pole pieces, an armature having a
forked commutator brush, and an insulated ring in multiple arc circuit with the
armature coils and a brush in series with the line, substantially as shown and
described.
W. P. THOMPSON & BOULT,
Agents.