An Improved Controlling Apparatus for Electric Motors.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
An Improved Controlling Apparatus for Electric Motors.
JOHN ALEXANDER STEVEN, 12, Royal Crescent, Glasgow, Engineer, and
WILLIAM RYLANCE HAIGH, 6, Elmwood Gardens, Broomhill, Glasgow, Engineer,
do hereby declare the nature of this invention to be as follows:
An improved arrangement and device of controlling apparatus for electric
motors the object of which is to automatically regulate and control the first rush
of current through motors when starting and in like manner to control diminish
and cut off the current when stopping.
For this purpose we employ in conjunction with any of the well known and
customary forms of switch a set of variable electrical resistance coils or rheostat
the handle or lever of which is operated by a governor of any of the well known
centrifugal types driven from the motor shaft either by direct attachment or
by belt or otherwise and so arranged that as the speed of the motor increases
the resistance coils are successively and gradually cut out until all are removed
out of circuit on the motor attaining full speed.
If it is desired to use the resistance as a choking coil for the purpose of reduc-
ing the current and showing down the motor prior to stopping we then employ
a similar governor and rheostat the handle or lever of which is hung or carried
upon a movable or floating fulcrum to which fulcrum the governor is connected.
One end of this lever carries a suitable form of quick acting or snapper switch
to complete or break the electrical circuit with the rheostat, the other end is
under the control of the attendant and may if so desired, be arranged to carry
another contact piece or switch. In operating this form of the apparatus the
attendant would by moving his end of the handle or lever bring the snapper
switch into contact with the first terminal of the rheostat closing the electrical
circuit and cause the motor to rotate at a comparatively slow speed an excessive
rush of current being prevented by the resistance of the rheostat. Under the
centrifugal action the governor now draws the snapper switch gradually and
successively across the terminals of the rheostat cutting out resistance and
increasing the speed at each step until finally all the resistance is cut out and
the motor runs at full speed.
In stopping the motor the attendant moves the handle of the rheostat in the
opposite direction to that of starting cutting in resistance and slowing down the
motor, the controlling springs of the governor then overcome the centrifugal
forces and cause the governor to operate the rheostat handle and cut in still
more resistance causing further slowing down, so re-acting on each other until
finally the snapper switch breaks contact and the motor stops.
Dated this 28th day of December 1899.
J. ALEX. STEVEN.
WM. R. HAIGH.

page_text: COMPLETE SPECIFICATION.
An Improved Controlling Apparatus for Electric Motors.
JOHN ALEXANDER STEVEN, of 12, Royal Crescent, Glasgow, Engineer, and
WILLIAM RYLANCE HAIGH, of 6, Elmwood Gardens, Broomhill, Glasgow,
Engineer, 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: :―
An improved arrangement and device of controlling apparatus to automatic-
ally regulate and control the first rush of current through electric motors when
starting, and in like manner to control diminish and cut off the current when
stopping.
For this purpose we employ a set of variable electrical resistance coils or
rheostat RT the handle or lever L of which is hung upon a movable fulcrum F
attached to and operated by any well known type of centrifugal governor G
which governor G is driven either by direct attachment to the motor shaft or
by belt or otherwise, so arranged that as the speed of the motor increases the
lever L is pushed forward and the resistance coils are successively and gradually
cut out, until all are removed out of circuit on the motor attaining full speed.
One end of this lever L carries a suitable form of quick acting or snapper
switch S¹ to complete or break the electrical circuit with the rheostat R T, the
other end is under the control of the attendant and may if so desired be arranged
to carry another contact piece or switch, S2.
In operating this form of apparatus the attendant by moving his end of the
rheostat handle or lever L would bring the switch into contact with the
first terminal of the rheostat R T closing the electrical circuit and cause the
motor to rotate at a comparatively slow speed, any excessive rush of current
being prevented by the resistance of the rheostat. Under the centrifugal
action, the governor G by operating the movable fulcrum F. now pushes the
switch S gradually and successively across the terminals of the rheostat RT
cutting out resistance and so increasing the speed of the motor, until finally all
the resistance is cut out and the motor runs at full speed.
To stop the motor, the attendant moves the handle L of the rheostat RT in
the opposite direction to that of starting, cutting in resistance and slowing
down the motor, the controlling springs of the governor G then overcome the
centrifugal forces causing the governor G to operate the rheostat handle L
and cut in still more resistance which causes further slowing down, the parts
so re-acting on each other until finally the switch S¹ breaks contact and the
motor stops..
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
The combination of a centrifugal governor with a rheostat the handle of which
is hung upon a movable or floating fulcrum or so connected with such floating
fulcrum and lever that the movement of the governor operates the rheostat
handle so automatically controlling the electrical current supplied to the motor
substantially as described and shewn upon the accompanying drawing.
1
T1. 1000
J. ALEX. STEVEN.
WM. R. HAIGH.