IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES, America INVENTION BEING ALSO APPLICABLE TO ELECTRIC MOTORS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Philip Middleton Justice at the
Office of the Commissioners of Patents on the 10th April 1883. Communi-
cated to him from abroad by
Keegan temporarily of the City of
Washington United States of America
PHILIP MIDDLETON JUSTICE of 55 Chancery Lane in the County of Middlesex
Fellow of the Institute of Patent Agents "IMPROVEMENTS IN DYNAMO-ELECTRIC
MACHINES, THE
a communication to me from abroad by
of Washington United States of America
INVENTION BEING ALSO
APPLICABLE TO ELECTRIC MOTORS
Keegan temporarily of the City
The object of this invention is First to reduce the amount of power required to
work a dynamo electric machine for the generating of an electric current, by
changing the polarity of the instant poles at time of motion without any disruptive
discharge and second to avoid the production of secondary induced currents in the
wire coil of the induced magnet and inducing magnet
The invention consists first in the relatively close arrangement of the poles of
the magnet both of the stationary and moving, whereby the poles of the moving
magnet at the instant of motion begin to pass before the opposite pole of the
stationary or inducing magnet thus causing opposite inductions to neutralize the
existing induced magnetism of opposite polarity in the poles and thus allowing
motion with great freedom from magnetic attraction
The second part of this invention consists in a special construction of the poles
of the magnets both inducing and induced, whereby the poles of one are made to
revolve between and in close proximity to the poles of the other and the magnetic
force is exerted more nearly in line parallel to motion of rotation The stationary
or inducing magnet may be an electro magnet or a permanent steel magnet The
general form of it is that of an ordinary horse shoe magnet but the poles are
formed of extension pieces which are turned towards each other at right angles to
the arms of the magnet The ends of these extension pieces are formed with
hollowed faces the hollows or depressions in the opposite faces forming when the
pieces are in position a cylindrical cavity extending quite across the faces Those

page_text: parts of the faces not cut away and opposite each other are separated by the space
ordinarily of from 1 to 1 of an inch but this space may be increased in very
large machines The space must be greatly less than the length of the face of
the moving pole so that said moving pole will begin to move before the face of
one pole of the fixed magnet as soon as it begins to leave the face of the other.
The induced magnet which is intended as the revolving magnet and except in the
form of the poles may be of ordinary shape The poles are formed upon the ends
of extension pieces fixed to the cores of the induced magnet said poles being bent
at right angles to said extension pieces They are in form longitudinal segments
of cylinders each less than a half cylinder with a space between the parts equal to
the spaces between the plain faces of the magnet heretofore described
The parts and spaces are so proportioned that the two poles form practically a
cylindrical body which when the magnets are set into their proper positions occupy
the cylindrical space between the poles of the magnet fitting as closely to the
hollowed ends as it may practically without touching at any point. Ordinarily
the annular space between the periphery of the poles and the walls of the cavity
of the poles of the magnet will be equal in width to that of a thick sheet of paper.
The induced magnet is provided with an ordinary coil of insulated wire with
connections which may be made in the usual manner and need not be herein
described The induced magnet may be mounted on an axis in any convenient
or well known manner so that it may be rotated at right angles to the cores This
rotation will cause the poles to revolve in the cavity between the poles of the
inducing magnet. In an apparatus of the proportions hereinafter described the
cylindrical extension formed by the poles will be approximately 7, of an inch
It will be apparent that when the poles are each exactly opposite a pole of the
inducing magnet each will be acted upon by the inducing poles to their full extent,
that is to say the said poles are then in a position of instant static polar condition
But as in their motion of rotation they begin to pass from this position before the
faces of the inducing magnet of opposite polarity they begin to receive inductions
of a polarity the opposite of that previously received which latter inductions tend
to neutralize the former At that point in the revolution where the poles of the
induced magnet are before or over lap equal parts of each pole or at ³/, revolution
from the position first specified, the inductions of opposite polarity are in
equilibrium and from this point is the position of a half revolution, the opposing
inductions prevail This construction therefore prevents any disruptive discharge
of the poles in their motion before the face of the static stationary magnet and
gives motion free to a greater extent from retarding magnetic attraction No
depolarization occurs at any point or instant but only successive changes of
opposite polarization
Instead of the hollowed poles of the stationary and the cylindrical poles of the
moving or induced magnets I may use poles with plain opposing faces though not
ordinarily with as good effect In this case the spaces between the poles of each
magnet must be of such small dimensions as compared with the area of the faces
of said poles that each pole of the moving magnet shall immediately upon its
.movement from position of instant static magnetic condition begin to pass before
the face of the opposite pole of the inducing magnet The form with cylindrical
poles is of special advantage for use in an electric motor for the reason that the
magnetic attraction between the poles of the inducing and those of the induced
magnet is more nearly in the direct line of motion than in the form and arrange-
ment of the poles in the ordinary motors. In the modification the principle of
the invention is employed in connection with a vibrating armature In this are
employed two inducing magnets set in different planes Between them is the
armature or induced magnet of such thickness in the face of its poles that as it
reciprocates from the plane of one magnet to that of the other, it shall begin to
pass before one immediately upon beginning to move from its position before the
other The position of the coil of the induced magnet, is entirely removed from

page_text: the field magnet at such distance that the said magnet cannot act directly on the
coils but only through the inducing magnet, no disturbing secondary currents can
occur in the coils caused by such direct induction and as I have found there is
greatly less tendency in the machines to heat
It is also to be understood that a helix or solenoid may be used as an armature
for induction in place of soft iron This solenoid must be constructed to act on
the same principle as the induced acting magnet or armature