IMPROVEMENTS IN GOVERNING APPARATUS APPLICABLE FOR DYNAMO OR MAGNETO ELECTRIC MACHINES, AND FOR THE USUAL FORMS OF ELECTRO-MOTORS
Year: 1881

page_text: LETTERS PATENT to William Phillips Thompson, of the Agency for Foreign
Patent Solicitors, G, Lord Street, Liverpool, in the County of Lancaster, and
323, High Holborn, in the County of Middlesex, Civil Engineer, for an
Invention of "IMPROVEMENTS IN GOVERNING APPARATUS APPLICABLE FOR
DYNAMO OR MAGNETO ELECTRIC MACHINES, AND FOR THE USUAL FORMS
OF ELECTRO-MOTORS." A communication from abroad from Professor John
Williams Langley, of the City of Ann Arbor, Michigan, in the United States
of America.
COMPLETE SPECIFICATION left by the said William Phillips Thompson at
the Office of the Commissioners of Patents on the 27th September 1881.
WILLIAM PHILLIPS THOMPSON, of the Agency for Foreign Patent Solicitors,
6, Lord Street, Liverpool, in the County of Lancaster, and 323, High Holborn, in
the County of Middlesex, Civil Engineer. "IMPROVEMENTS IN GOVERNING
APPARATUS APPLICABLE FOR DYNAMO OR MAGNETO ELECTRIC MACHINES, AND
FOR THE USUAL FORMS OF ELECTRO-MOTORS." A communication from abroad
from Professor John Williams Langley, of the City of Ann Arbor, Michigan, in
the United States of America.
"Figure 1 is a side view of the electro-magnet of a dynamo-electric machine, the
armature and shaft being shown as simple rings, and Figure 2 is an end view of
the same magnet, with my Invention attached thereto.
"
My Invention consists in suspending a piece of magnetic metal by suitable
mechanism in such relation to the poles of the electro-magnet in a dynamo-electric
machine that when such machine produces more current than is required by the
work to be done by it, the attraction of the poles upon the piece of magnetic metal
will become so strong as to overcome the resistance of the suspending mechanism,
cause the piece of magnetic metal to approach the poles, and tend to establish
magnetic communication between the poles, thereby reducing the current generated
by the machine.
"In the Drawings A is an electro-magnet, of which P, P, are the poles; B is an
armature which revolves on the shaft S between poles P, P. Armature B may be
any known type, such as the Pacinotti ring armature.
"C, C¹, are pieces of magnetic metal long enough to reach from one pole P to the

page_text: other pole P, and may be made curved, as shown in the Drawings, or any convenient
shape which will allow pieces C, C', to extend from one pole to the other without
touching the armature B.. I usually make picces C, C, the same width as poles P,
but it is not necessary to make them so wide. While two of theso pieces C, C',
are shown in the Drawing, only one of them is necessary to the use of my
Invention, as ono operates sufficiently well for all practical purposes.
“D”, D„, D are guide rods of diamagnetic inaterial (as brass) fastened to
poles P, P, as shown in the Drawing, and serve as supports for the springs which
resist the approach of the free ends of pieces C, C', towards poles P, P. N, N., N,,
are screw nuts working on threads cut on guide rods D₁, D., D, by which the
distance of the free ends of pieces C, C, from poles P, P, can be adjusted.
"T, TT, are spiral springs made of some diamagnetic material (such as brass)
and are placed between the free ends of pieces C, C¹, and polos P, P, being
supported by guide rods D₁, D₂, D¸.
H, H', are pivots or hinges by which pieces C, C¹, are fastened at one end to
poles P, P, and on which pieces C, C¹, swing.
"The principle and mode of operation of my Invention is as follows:-
"It is well known that the efficiency of a dynamo-electric machine depends
upon the amount of free magnetism in the electro-magnet. If the poles of the
electro-magnet be connected by a magnetic substance (which is equivalent to pro-
longing the poles until they meet and form a magnetic ring around the armature),
the free magnetism in such electro-magnet will be greatly diminished, the magnetism-
therein becoming bound, and in proportion-as-a-magnetic connection-is-more nearly
established between the poles of such electro-magnet the amount of free
magnetism therein will be diminished, and the current produced by the machine
weakened.
"It follows then that if in a dynamo-electric machine a piece of magnetic metal
be held by springs or other suitable mechanism at such a distance from the poles
of the electro-magnet that the machino will generate just enough current for the
wants of the external circuit of such machine, a diminution of the resistance of
the external circuit or an increase in the speed of the armature will cause the poles
of the magnet to exert an increased attraction upon the magnetic metal piece, the
resistance of the supporting springs will be partially overcome, the magnetic metal
piece will approach the poles of the magnet and tend to establish magnetic con-
nection between them, thus diminishing the amount of free magnetism in the
magnet and weakening the current produced by the machine.
"
The spring T, is made of such strength and length that when the dynamo-
clectric machine shown is supplying just the amount of current needed in the
external circuit of the machine, said spring T, will hold the free end of magnetic
metal piece C at a fixed distance from pole P. As the power of such machines and
the current required from them differs so greatly it is impossible to prescribe any
given strength for said spring, but it is a comparatively easy matter for any maker
of electrical machinery to adjust said spring to the power of any particular
machine.
"As long as the resistance of the external circuit remains constant, or nearly so,
the free end of piece C will remain nearly stationary, having however a slight
vibratory movement to compensate for variations in the resistance of the external
circuit. If now the resistance of the external circuit be diminished, as, for
instance, by extinguishing one or more electric lamps out of a number of lamps in
said circuit, or if the speed of the armature be increased, the attraction of pole P
upon the free end of magnetic metal piece C will increase so as to overcome the
resistance of spring T., the free end of magnetic metal piece C will be drawn
towards pole P, thus diminishing the free magnetism in magnet A, and weakening
the current produced by the machine. When the resistance of the external circuit
again becomes as great as at first, or the speed of the armature is decreased, pole P
ceases to attract the free end of magnetic metal piece C so strongly, and spring T,
forces the free end of said piece C away from said pole.

page_text: "As the magnetic attraction of pole P upon the free end of magnetic piece C
increases in strength with the approach of the free end of said piece C to said
pole P faster than the resistance of spring T, increases I employ shorter supple-
mental springs T₁, T, which successively come into play, and thus increase the
resistance to the approach of the free end of piece C to pole P in practically the
same ratio as the magnetic attraction increases. The length and strength of these
supplementary springs should be adjusted, as hereinbefore explained with regard to
spring T
"My Invention will work with only one spring, but its operation is much
more complete, thorough, and satisfactory, with two or three springs, as shown and
described.
"As an electro-motor is simply a dynamo-electric machine used to convert
electricity into power instead of power into electricity it is obvious that the speed
of such motors will be governed effectively by my Invention.
"
Having thus described my Invention, what I claim as new and desire to secure
by Letters Patent is,―
"1. The combination with the poles of an electro-magnet in a dynamo or
magneto-electric machine of a magnetic metal piece and mechanism, sustaining the
same in such relation to the poles of the electro-magnet that an excess of current
will cause the poles to attract the magnetic metal piece and tend to establish
magnetic communication between tho poles through said magnetic piece.
2] The combination with the poles of the magnet in a dynamo or magneto-
electric machine, of a magnetic metal piece connected at one end with one of the
poles and mechanism for sustaining the other end of the magnetic metal piece at a
xed distance from the other pole in such relation thereto that an excess of current
will cause the pole to attract and swing the magnetic metal pieco and tend to
establish magnetic communication between the poles, substantially as described
and shown.
"3. The combination of the poles P, P, of the magnet in a dynamo or magneto-
electric machine with the movable magnetic metal piece C or pieces C, C³, and
diamagnetic springs T₂, as and for the purposes set forth.
"4. The combination of the poles P, P, of the magnet in a dynamo or magneto-
electric machine with the movable magnetic metal piece C and diamagnetic springs
T, T₂, T, as and for the purposes set forth.
5. The combination with the poles of the magnet in a dynamo or magneto
electric machine of a magnetic metal piece pivotally connected at one end with
ono of the poles and a spring or springs sustaining the other end of said magnetic
metal piece in such relation to the other pole that an excess of current will cause
the pole to attract the same so strongly as to partially overcome the resistanco
of the spring or springs, and tend to establish magnetic communication between
the poles through the magnetic metal piece, substantially as described."
In witness whereof, I, the said William Phillips Thompson, have hereunto
set my hand and seal, this Twenty seventh day of September, in the year of
our Lord One thousand eight hundred and eighty one.