Improvements in Electric Motors.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Motors.
I, STANLEY CHARLES CUTHBERT CURRIE of 5th and Chesnut Streets, Philadelphia, in
the County of Philadelphia, State of Pennsylvania, 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, and has special relation to that class
of motors wherein there are more than two active poles, and which have in consequence
more than two brushes on the commutator.
My invention has for its object, the provision of means whereby the power of the
motor can be graduated according to the number of brushes on the commutator;
and my invention has for its further object, the provision of means whereby the
direction of motion of the motor can be readily and easily reversed and the power of
the motor increased or diminished in equivalent generations for both the forward and
backward movements of the armature.
My invention consists in the provision of novel means, whereby in a motor having
more than two brushes adapted to contact with the commutator, the brushes may be
successively thrown into or out of contact with the commutator to increase or
decrease the power of the motor.
My invention further consists in the provision of means whereby, in a motor
provided with more than two brushes the direction of motion of the moving portions
of the motor may be readily and speedily reversed and the power increased gradually
from the starting point in either direction.
My invention still further consists in the novel constructions, combinations and
arrangements of parts hereinafter described.
In carrying my invention into effect I provide a number of brushes equal to the
number of active poles which the motor may have and secure each brush at or about
its centre to a holder that is swiveled upon a stationary frame and to each such holder
I attach one end of a spring the other end of which passes between a pair of jaws,
rollers or equivalent guides secured upon a frame movable in a direction concentric
with the commutator and provided with a suitable handle. The jaws or the rollers
which embrace the springs are so arranged relatively to the swiveled brush holders
that upon moving the frame upon which they are carriod, the brushes are caused to
make contact or break contact with the commutator in succession, thereby gradually
increasing or decreasing the power of the motor.
The movable frame and its attached gripping jaws are also arranged so that upon
passing a certain point, and after all the brushes have been caused to break contact
with the commutator the opposite ends of said brushes will be successively brought
into contact with the commutator.
At or
Referring to the accompanying drawings wherein I have illustrated a motor having
my improvements applied thereto and wherein Fig. 1 is an elevation of the motor
looking towards the end of the commutator. Fig. 2 is a top view of the commutator
and appurtenances, and Figs. 3, 4, 5, 6, 7, 8 and 9 are detail views of parts of the
same. A designates the armature, B the commutator, C the main shaft and D the
field magnet poles,' all constructed in the usual or any appropriate manner.
near one end of the commutator B and concentric with shaft C is a fixed circular plate
or disk E, said plate E is embraced by a metallic ring F having a handle F by
means of which it may be moved in either direction around the plate, the amount
of motion being limited by a slot e in the ring through which passes a stud e¹ on the
plate. At equal distance apart and near the edge of the plate E are a number of radial
slots G, through which pass pins H, H, screw threaded to receive nuts h, h, by means
of which the pins are held in position in the slots at any desired distance from the center

page_text: arranged to turn concentrically with said commutator and four or more brushes
connected to said section and adapted to be successively or at intervals raised out of
contact with the commutator by the movement of the said section, substantially as
described.
2nd. In an electric motor, the combination with a commutator and four or more
brushes each secured in pivotal brush holders adjacent to said commutator and with
their free ends in contact therewith, of a movable section connected to each brush
holder by a spring the springs being each strained to greater degree than the preceeding
one, whereby as such section is moved the brushes will be successively raised from
contact with the commutator, substantially as described.
3rd. In an electric motor, the combination of a commutator, a series of brushes,
pivotal brush holders, springs connected to said brush holders, a movable section or
rollers, or jaws carried by said section and adapted to embrace said springs, the jaws
being arranged at variable intervals on a circular line concentric with said commutator
substantially as described.
4th. In an electric motor, the combination with a commutator and four or more
double ended brushes attached at the center to swiveled brush holders, a movable
section carrying clamping jaws arranged concentrically to said commutator at
unequal distance apart and springs projected through said jaws and connected to said
holders, whereby the brushes may be successively raised from contact with the
commutator and their opposite ends successively brought into contact therewith by a
progressive movement of said movable section, substantially as described.
5th. In an electric motor, the combination with a commutator, brushes adapted to
contact therewith, swiveled brush bolders and a movable ring or section carrying
clamping jaws or rollers secured in swiveled frames, adjustably secured to said
movable section, of springs having one end attached to the brush holders and the other
end projected through said clamping jaws, substantially as described.
6th. In an electric motor, the combination with commutator B, brushes M1, M2, M3, M*,
swiveled brush holders L', L, L, LA, of movable ring E carrying swiveled frames N, N,
with clamping rollers n, n, and Hat springs K, K³, K³, K, attached to said brush
holders and passing between said rollers all constructed and arranged, substantially
as described.