Improvements in and connected with Automatically Operating Variable Resistances in Electrical Circuits.
Year: 1896

page_text: Date of Application, 3rd Mar., 1890
Complete Specification Left, 1st Dec., 1896-4ccepted. 6th Feb.
Mar., 1890
Complete Specification Left, 1st Dec., 1896-4ccepted. 6th Feb.
PROVISIONAL SPECIFICATION.
Improvements in and connected with Automatically Operating
Variable Resistances in Electrical Circuits.
We, CECIL BURMAN CALLOW of Great Missenden in the County of Bucks,
Electrical Engineer, and HENRY BEVIS of 71 Queen Victoria Street in the City
and County of London, Electrical Engineer, do hereby declare the nature of this
invention to be as follows:-
Our invention relates to automatically operated variable resistances in electric
circuits and has for its object the provision of an automatic governor in a power
or other installation which is subjected to an intermittent load."
In carrying our invention into effect we use a trough or tank filled with mercury
or any other fluid possessing similar qualities of conductivity a series of plates of
any suitable metal are arranged so as to be permanently immersed in the trough
or tank and these are of varying length, so that the area of immersion of each
plate at any given level is differential according to a predetermined scale.
Each plate is coupled in series with an interposed resistance of a calibrated
degree according to the range of the apparatus and the purpose to which it is to
be applied. It is evident that a regulative resistance may be effected by either
raising or lowering the plates in the conductor liquid or varying the level of the
latter, producing a corresponding increase or decrease of the area of the conducting
surface aforesaid, and cutting out or placing in the circuit such resistance coils or
the like which connect the plates of lesser area.
We prefer to vary the liquid level of mercury or other liquid, fluid, or viscous
conductor by placing a reservoir of said metallic or other conductor, upon a
pivotted rod, with a vertical fulcrum which is held in a normal position by a spiral
or other spring. An electromagnet, the coils of which are in series with the
circuit is arranged so as to attract the reservoir aforesaid, against the tension of
the spring and cause it to raise the level of the liquid conductor within, the tank
or trough. When the load becomes excessive, the raising of the reservoir
practically short circuits the resistance coils between the plates, and the total
current is increased when required. The back E.M.F. of the motor, lamp, or
other apparatus to which this regulator may be applied, causes the magnetic effect
of the magnet to vary in direct proportion to the current, and in other cases of
adaptation the regulation is effected by the automatic adjustinent of the normal
resistance of the whole circuit.
As an alternative device, we may use an armature at the end of a lever, which
by a delicately adjusted counter poise will raise the plates out of a constant
liquid level by means of the magnet in circuit as herein before described, or be
the action of the core of a solenoid, with any system of levers or counterpoises, or
suitable gearing interposed.
We may vary the details to suit varicus conditions of adaptation without
departing from the essential features of the invention.
Dated this 25th day of February 1896.
FREDK. WALKER,
Fellow of the Society of Patent Agents,
73 St. Stephen's Road, Upton Park, London, Agent for the Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in and connected with Automatically Operating
Variable Resistances in Electrical Circuits.
We, CECIL. BURMAN CALLOW, formerly of Great Missenden in the County
of Bucks, now of Alford Road Erith, in the County of Kent, Electrical Engineer
and HENRY BEVIS of 71 Queen Victoria Street in the City and County of
London 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:-
Our invention relates to automatically operated variable resistances in electric
circuits, and has for its object, the provision of an automatic governor in an
electric power or other installation which is subjected to an intermittent load.
In order that our invention may be the better understood we have appended
the accompanying sheet of drawings, in which the device is shown partly in
section.
In carrying our invention into effect we use a trough or tank G partially filled
with mercury or any other fluid possessing similar qualities of conductivity.
A series of plates p of any suitable metal are arranged so as to be immersed in the
trough or tank G, and these are of varying length so that the area of immersion
of each plate at any given level is differential according to a predetermined scale.
Each plate is coupled in series with an interposed resistance r of a calibrated
degree according to the range of the apparatus and the purpose to which it is to
be applied. It is evident that a regulative resistance may be effected by raising
or lowering the plates in the conductive liquid or fluid, or varying the level of the
latter, producing in both cases a corresponding increase or decrease of the area of
the conducting surfaces, and cutting out, or interposing, such resistance coils
which are placed between the plates p and short circuited when these are immersed.
In our Provisional Specification we have described a balanced lever and electro
magnet or solenoid, but in practice we prefer to vary the level of the conductor
fluid by means of a flexible tube, in combination with a solenoid A.
Said solenoid A has a core C, carrying a reservoir B, holding mercury or the
like m and provided with a plunger or float D, which is balanced by immersion in
a mercury chamber E, so that the action of the solenoid A may be sensitive to any
luctuation of the current.
The mercury, or other liquid or fluid conductor m in the reservoir B is connected
to the tank or trough G by means of a flexible pipe F, which offers no resistance
to the pull of the solenoid A, and maintains by gravity the liquid level in B
and G. We may substitute a dash pot, or spring for compensating the weight of
the core C and reservoir B.
The coils of the solenoid A being in series with the circuit; upon an access
of current, raises the reservoir B and consequently the level of the conducting
fluid in the tank G, thus short cireuiting more of the resistances by reason of
immersion of the plates p, in addition to the variation of resistances due to the
irregular areas immersed at any given level. We may use V shaped plates in
order to render the action more sensitive.
When the load becomes increased, the current is proportionately increased by
the cutting out of the resistances r. The back E.M.F. of the motor, lamp or
ther apparatus to which this regulator may be applied causes the magnetic effect
of the solenoid to vary in direct proportion to the current, and in any ense of
adaptation we prefer to effect the aforesaid regulation by means of automatically
varying the level of a mercury or other conductive liquid bath as described.

page_text: Having now fully described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is ;-
In apparatus for automatically operating variable resistances in electrical
circuits, the combination of a solenoid A in series with the circuit, a core C,.
mercury reservoir B and compensator E, with a tank G with plates p and
resistances connected to B by a flexible tube F, substantially as and for the
purposes as herein described and shown by the appended drawings.
Dated this 25th day of November 1896.
FREDK. WALKER,
73, St. Stephen's Road, Upton Park, London, E.,
Agent for the Applicants.