IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
Year: 1882

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of "IMPROVEMENTS IN
DYNAMO-ELECTRIC MACHINES." A communication from abroad by Henry
Brinsley Sheridan, of Cleveland, in the County of Cuyahoga, State of Ohio,
United States of America, Civil Engineer.
COMPLETE SPECIFICATION filed by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 25th February 1882.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES."
A communication from abroad by Henry Brinsley Sheridan, of Cleveland, in
the County of Cuyahoga, State of Ohio, United States of America, Civil Engineer.
The object of this Invention is to produce dynamo electric machines so
constructed that the current induced in the armature will be without wide breaks
and nearly continuous, and also to increase the efficiency of the said machines.
The Invention consists in a dynamo-electric machine constructed with its field
magnets made oblong in cross section, and arranged in two series in a circle
around the armature shaft with the poles of the opposing series facing each other,
and arranged at a sufficient distance apart to receive the armature between them,
the poles of each series nearly overlapping each other laterally, forming a nearly
continuous magnetic field; also in the armature constructed of a hollow iron ring
nearly rectangular in cross section, and with its sides converging or inclined
inwards from the periphery towards the inner side; also in the hollow ring
armature made with corresponding openings in its periphery and inner sides, and
projections of uniform thickness upon its inclined or converging sides, whereby
the outer part of the armature is brought nearer to the magnetic field of force
than the inner part; also in the hollow ring armature made with two series of
projections of different shape alternating with each other, the projections of the
one series being made V shaped or with converging sides, and the projections of
the other series being made with slightly inclined or converging sides and V shaped
ends, whereby channels or grooves of uniform width are formed to receive the
helix coils; also in the combination with the armature having lugs and the

page_text: armature shaft of the hubs having flanges, whereby the said armature will be
firmly connected with the said shaft; also in the combination with the armature
and the armature shaft of the stationary magnet cores and the helices, the said
cores being placed spirally around the armature shaft and at an inclination with
the said shaft, and the said helices being wound with their coils parallel with the
magnetic field of force, whereby the field of force will be elongated in the direction
of the armature's movement, as will be hereinafter fully described.
In the accompanying Drawings, Figure 1 is a side elevation partly in section
of the machine; Figure 2 is a plan view of the same, partly in section ;
Figure 3 is a sectional end elevation of the same taken through the line x, x,
Figure 1, showing one magnet in end view and the other in section and with the
helix wires removed; Figure 4 is a sectional end elevation of the same taken
through the line y, y, Figure 1; Figure 5 is a sectional end elevation, showing a
modification of the machine; Figure 6 is a sectional plan view of the same taken
through the line 2, 2, Figure 5; Figure 7 is a sectional side elevation of a modifi-
cation of the same taken through the line w, w, Figure 8; Figure 8 is a sectional
end elevation of the same taken through the line v, v, Figure 7. Similar letters of
reference indicate corresponding parts in all the Figures.
A is the bed plate of the machine; B are two standards attached to the bed
plate A, and having bearings in which revolves the shaft C that carries the
armature. The standards B also form the seats and supports for the stationary
magnet cores E, around which are wound helices F of insulated copper wire. The
magnet cores E stand with their axes in a spiral line of convenient direction and
pitch around the axis of the shaft C. With this arrangement the stationary
magnet cores present an oblong field of force to the armature, the length of the
field of force depending upon the pitch of the magnet cores E and their inclination
from the axis of the shaft C. The magnet cores E are arranged with the longest
diameters of their fields of force in the direction in which the armature revolves,
by which arrangement the projections of the armature will remain longer in the
fields of force, and the generated currents will thus be considerably increased. One
of the magnet cores E with the surrounding helix can be one pole of an electro
magnet, or two or more of the said cores E can be connected on their faces by a
plate G, and thus form only one pole of an electro-magnet.
As shown in Figures 1, 2, and 3, each standard B has two magnets, each formed
of two magnet cores E connected at their poles by a plate G, but four or more
magnets can be used upon each standard if desired. The armature core D is made
in the form of a hollow iron ring, and is nearly rectangular in cross section. The
sides of the armature core D converge slightly from the periphery of the said ring
to its inner side, as shown in Figure 1. In the periphery of the armature core D
are formed a number of openings H, and in the inner side are formed a corre-
sponding number of openings I, as shown in Figures 1, 2, and 4. Upon the sides
of the armature core D are formed projections J, K, the outer surfaces of which
converge or incline so as to be parallel with the sides of the body of the said
armature. The projections J are made V shaped and terminate at or near the
inner side of the armature core D, or may extend in a thin blade a little beyond
the said inner side of the said armature core D. The sides of the projections K are
slightly inclined or converged to or nearly to the inner side of the armature core D,
and their ends are made ✓ shaped, and terminate at or a little beyond the said
inner side of the said armature core D. The outer ends of the projections J, K,
may terminate at the periphery of the armature core D, or may project a little
beyond the said periphery. The projections J, K, thus forin pairs of grooves or
channels of uniform width, in each pair of which is wound a single helix L of
insulated copper wire. The outer end of each helix wire L is connected with the
inner end of the next helix wire L, and both are connected with one of the sections
of the commutator M, the number of sections of the commutator M being equal to
the number of helices L when only one commutator is used. When two commu-
tators M are used, as shown in Figure 2, the outer end of the first belix is

page_text: connected with the inner end of the third helix, and both are connected with a
section of one of the commutators M, and the outer end of the second helix is
connected with the inner end of the fourth helix, and both are connected with a
section of the other commutator. In this case each commutator has half as many
sections as the armature has helices.
Upon the side edges of the inwardly projecting ends of the projections K are
formed projections or lugs N, which engage with the flanges O of the hubs P placed
upon and secured to the shaft C that carries the commutator M, so that the
armature when expanded by heating will be held firmly in place. The armature
core D can be made in segments or sections, which will be held together at the
inner side of the said armature core by the interlocking of the lugs N with the
flanges of the hubs P, and at the periphery of the said armature core by screws Q
and lugs R, as shown in Figure 4. S are brushes or springs which rest upon the
commutator M and make the connection between the helices L of the armature
and the helices F of the electro magnets. The helices F are wound with their
coils parallel with the field of magnetic force instead of being wound at right
angles with the magnetic cores E, as shown in Figures 1 and 2.
In case the machine is constructed for the armature to revolve inside of the
series of electro magnets, rows of magnet cores E' are placed in spiral lines around
the armature shaft C¹, each core E' being radial to the said shaft, as shown in
Figures 5 and 6. Two, four, or more of the magnet cores E' can be placed around
the armature D', being secured at their outer ends to a ring, hollow cylinder, or
other suitable support. Several magnet cores E' can be used for one magnet, or a
single core can be placed in a spiral line around the armature.
In the modification shown in Figures 7 and 8, the series of magnets are arranged
in circles around the shaft C, one series being attached to each frame B. The
magnet cores E² are made oblong in cross section, and are arranged in inclined
positions with reference to each other, so that they nearly overlap each other
laterally, the side of one magnet being tangential to the rounded edge of the
adjoining magnet, and so on throughout the series. With this arrangement the
face of the pole of each magnet is arranged diagonally across the path of the
armature ring in the plane of its rotation, as shown in Figure 8. This construction
brings the magnets into such positions that each section coil L of the armature
will pass upon the pole of each magnet at the instant it leaves the pole of the
preceding magnet, so that the current induced in the armature will be without
wide breaks and will be nearly continuous. With this construction the armature
can be revolved in either direction. The construction and arrangement of magnets
last described is preferred as providing a more effective machine.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as new and desire to secure by Letters
Patent is,-
1st. A dynamo-electric machine, constructed substantially as herein shown and
described, with its magnets made oblong in cross section, and arranged around the
armature shaft C with the side of each magnet in the series nearly overlapping the
edge of the adjacent magnet, substantially as herein specified.
2nd. In a dynamo-electric machine the armature core D, constructed substantially
as herein shown and described, of a hollow iron ring nearly rectangular in cross
section, and with its sides converging or inclined inward from the periphery
towards the inner side, as set forth.
3rd. In a dynamo electric machine the armature core D constructed, substantially
as herein shown and described, of a hollow iron ring having corresponding openings
H, I, in its periphery and inner side, and projections J, K, forming channels of
uniform width upon its inclined or converging sides, as set forth.
4th. In a dynamo electric machine the armature core D constructed, substantially
as herein shown and described, of a hollow iron ring having upon its sides
projections J, K, of different thicknesses alternating with each other and projecting
beyond the inner side of the core, the projections J being V shaped or with sides

page_text: converging to an edge, and the projections K being made with slightly inclined or
converging sides and V shaped ends, whereby channels or grooves of uniform
width are formed to receive the helix coils, as set forth.
5th. In a dynamo-electric machine the combination with the armature core D
having lugs N, and the armature shaft C of the hubs P having flanges O,
substantially as herein shown and described, whereby the armature will be firmly
connected with the said shaft, as set forth.
6th. In a dynamo electric machine the combination with the armature and the
armature shaft C of the stationary magnet cores E and the helices F, substantially
as herein shown and described, the said cores being placed spirally around the
armature shaft and at an inclination with the said armature shaft, and the
said helices being wound with their coils parallel with the magnetic field of force,
as set forth.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty fifth day of February, A.D. 1882.