Year: 1885

page_text: I, EDWARD JOHN HOUGHTON of No 1 Pilkington Road, Peckham in the County
of Surrey, Electrical Engineer, do hereby declare the nature of this invention to
be as follows:-
My invention has for its object either to vary the strength of electric current
from a dynamo electric machine or to intercept such current altogether when the
machine attains a certain speed. I accomplish this by causing the motion of the
armature spindle of the machine to effect the raising of mercury or other conducting
liquid in a vessel so as, when a certain speed is attained to make a contact and
thus close an electric circuit comprising an electro magnet, the motion of whose
armature causes a resistance to be introduced into the main circuit or shunt
circuit of the machine, whereby the current will be diminished. Or the armature
of the electromagnet is made to break a contact whereby the main circuit or shunt
circuit is entirely broken.
Various arrangements may be employed for carrying out the said invention, thus
according to one arrangement a screw blade contained in a vessel filled with mercury
is driven by a strap from the armature spindle so as to cause the mercury to rise in
a tube of insulating material in the upper part of which is the one contact of a
circuit containing an electromagnet, the other terminal of which is formed by the
vessel containing the mercury, so that the latter in closing the circuit causes the
armature of the electromagnet to be attracted and thereby to introduce a resistance
into the main or shunt circuit of the machine, whereby the current will be
diminished.
The insulated tube may contain one or more other contacts at higher levels, so
that should the speed of the machine be further increased, one or more other
contacts will be made by the mercury, thereby introducing one or more further
resistances into the circuit. Or the said insulated tube may have a side opening
at a certain height, communicating with a second tube containing the said contacts,
so that the mercury when raised to the height of the said opening, will flow into
the second tube and make the necessary contact or contacts. From the second tube
the mercury would flow back into the chamber through a restricted opening.

page_text: EDWARD JOHN HOUGHTON 1 Pilkington Road, Peckham S.E Electrical 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 :—
My invention has for its object either to vary the strengh of an electric current
from a dynamo electric machine or to intercept such current altogether when the
machine attains a certain speed-I accomplish this by causing the motion of the
armature spindle of the machine to effect the raising of mercury or other conducting
fluid in a vessel so as when a certain speed is attained to make a contact and thus
close an electric circuit comprising an electro magnet, the motion of whose armature
causes a resistance to be introduced into the main circuit or shunt circuit of the
machine whereby the current will be diminished-Or the armature of the electro
magnet is made to break a contact whereby the main circuit or shunt circuit is
entirely broken.
By this invention a screw blade contained in a vessel filled with mercury is
driven by a strap from the armature spindle so as to cause the mercury to rise in
a tube of insulating material in the upper part of which is the one contact of a
circuit containing an electro magnet, the other terminal of which is formed by the
vessel containing the mercury, so that the latter in closing the circuit causes the
armature of the electro magnet to be attracted and thereby to introduce a resistance
into the main or shunt circuit of the machine whereby the current will be
diminished.
The insulated tube may contain one or more other contacts at higher levels, so
that should the speed of the machine be further increased one or more other
contacts will be made by the mercury thereby introducing one or more further
resistances into the circuit.
A reference to the drawing will show how this is accomplished.
A is a metal cylinder containing mercury within which is a coarsely threaded
screw,
B. is the pulley of the screw which is actuated by a strap on the dynamo
armature spindle.
When the armature spindle turns, the screw on the pulley B. revolves also and
causes the mercury or other conducting fluid to rise in the tube C-When the
speed of the dynamo is sufficient the mercury makes contact with the metal pin D,
operating the electro magnet E and inserting the resistance F. into the main or

page_text: shunt circuit-When the mercury rises still higher it makes contact with the
pin G operating the electro magnet E. and inserting the additional resistance I.
Instead of inserting resistances the circuit may be broken.
Fig. 1 is the cylinder containing mercury.
Fig. 2 is an electro magnet with resistance already inserted in the circuit.
Fig. 3 is an electro magnet with resistance not put in the circuit.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
The use of electro magnets for inserting resistances into electric circuits and for
disconnecting such circuits at varying speeds of the dynamo machine substantially
as hereinbefore described.