An Improved Instrument for Regulating Electro Motive Force and Current.
Year: 1889

page_text: Date of Application, 14th Sept., 1889-Accepted, 23rd Nov., 1889
COMPLETE SPECIFICATION.
An Improved Instrument for Regulating Electro Motive Force and
Current.
We, WILLIAM HENRY DOUGLAS of Stourbridge in the County of Worcester
Electrical Instrument Maker and THOMAS HUGH PARKER of New Bridge Wolver-
hampton in the County of Stafford Electrical Engineer do hereby declare the nature
of our said 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 has for its object an improved instrument for regulating Electro
motive force and current, and is applicable to electric lighting and other purposes
where variations take place through change in the temperature, and through variations
in work.
We accomplish this automatically by the use of a differential device which is so
arranged as to compensate for change of temperature.
One portion of this device is operated upon by electric current and so thrown out
of balance the other part following the normal temperature and thus compensating for
the effect of a rise or fall in temperature and work.
In the construction of our instruments we use a balance bar the action of which is
controlled by the device, that is to say the bar is stationary when the thermometers
are alike or when they move in unison.
But immediately an excess of E M F occurs in the circuit one part of the device
expands so operating the said balance bar thus through it throwing in resistance to
reduce the EMF or otherwise should a fall occurr the contraction operates the bar,
and removes the resistance and thus increases the EMF so controlling the regularity
or constancy of the E M F.
This instrument may be applied for regulating the current as well as the EMF.
In order that our invention may be clearly understood and more easily carried into
practice we have appended hereunto two sheets of drawings upon which we have
fully illustrated our invention as well as the various connections thereto.
On sheet 1. Figure 1 is an exterior Front elevation of the instrument. Figure 2 is
an exterior side elevation.
On sheet 2 Figure 3 is a general interior view. Figure 4 is a side elevation of the
pulley D.
In carrying our invention into effect we connect the electric current to the
terminals at of the differential device A in which the action of the atmospheric
temperature upon the wire a' through which the current passes is compensated for by
the rods a which are acted upon solely by the temperature this being effected by
means of the wire a' passing over the pullies a³ which are in turn mounted upon the
ends as of the rods a² which are fixed at the ends a' so as to more or less alter the
position of the pullies a³ when any expansion or contraction of the bars a² takes
place thereby compensating for a similar action of the temperature upon the wire a¹.
The ends of the wire are fixed to the terminals at so that the position of the
pulley B is altered by the contraction or expansion of the said wire a¹ as the electrical
current passes through and the pulley B being mounted upon the rod 6' which is
operated in one direction by the pull of the contractions springs 62 and ³ the move-
ment of the rod 6' with the assistance of the chain 6 revolves the pulley D upon the
arbor and upon the pulley D the pin d¹ is fixed so as to press the balance bar E
which is mounted to move loosely on the arbor d against the resistance of the con-
traction spring e' thus retaining the end e² of the balance bar E midway between the
contact tables F and F¹ the wire a¹ being adjusted as hereafter described so that this
midway position shall take place when the EM F is not above or below the required
strength.

page_text: In the case of an excess of E MF in the circuit the wire a' expands thus through
the pulley B and rod B₁ allowing the spring 6 to contract and by the aid of the
chain 6 revolve the pulley D merely causing the pin d to press against the balance
bar E sufficiently to cause the ends ea to forin contact with the table F¹ which is so
connected with any approved form of resistance as to increase the amount of the
resistance and so reduce the EMF or should a fall in the EM F occur the contraction
of the wire a withdraws the pressure of the pin d' from upon the balance bar E and
allows it by means of the spring e¹ to form contact with the table F which removes the
resistance and increases the EMF and by these means a regularity & constancy in
the EMF is secured.
It will be seen that in case of the wire a¹ breaking the spring 63 would operate the
pulley, and form continued contact between the balance har E and contact table Fl
thereby forming a continual resistance which would reduce the EMF to minimum.
To obviate this we provide the balance bar H which is mounted upon the arbor ¹
and provided at the one end with the ring through which the rod 61
passes the other end being made so as to normally form contact with the contact
table K so as to complete the circuit but in case of breakage of the wire a¹ the rod b¹
would be drawn down by the spring 62 until the boss 65 which is provided upon the
rod 61 presses down the end 2 of the lever sufficiently to break contact between
the end of the lever H and the table K and form contact between the end h³
of the balance bar H and the contact table K¹ thereby breaking the connection with
the battery Z and the resistance and forming circuit with the battery Y and
alarm X.
To cut off the circuit of battery Z when the instrument is not required by reason
of no electric current passing through the wire a' we provide the pin d³ upon the pulley D
which as the wire a¹ contracts is revolved by the pull of the rod 6' until the pin d³
operates the lever H which is attached to the balance bar H thus breaking contact
between the contact table K and the balance bar H and through that the circuit of
the battery Z.
In case of the falling of the rod 61 through breakage of the wire a¹ or other causes
the friction pulley N is mounted upon the arbor d' by the arm d³ with the spring n³
which has a tendency to carry the pulley in the direction of the arrow n¹ so as to take
up any slackness which may thus occur in chain 6 and so prevent it from losing its
position upon the pulley D. For the purpose of adjusting the instrument to the
strength of the EMF required the thumb screw P is connected with the worm
wheel which by means of the toothed wheel p² operates one of the terminals a¹ of
the wire a¹ and thus causes the terminal to act as a drum upon which more or less
of the wire is wound as may be required by reason of the variations of the strength
of the EM F or the quantity of current required.
We do not confine ourselves exactly to the transferring mechanism shewn-though
that is quite new and we claim it as we may use differential gearing through which
the two thermometers are connected in which case we mount the balance bar E upon
the spindle or shaft of the differential gearing so that the actions of the atmospheric
compensating device is utilized for the same purpose of regulating the electro motive
force and current. Of course we lay no claim to the differential device when
working alone.
Having now particularly 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 :-
First. An improved instrument for regulating electro motive force and current in
which the pulleys B and D and balance bars E and H are operated by the differential
device A substantially as and for the purpose herein set forth and shewn upon the
drawings.
-
Second. An improved instrument for regulating electro motive force and current
on which the differential gearing and balance bars E and H are operated by a
differential device substantially as and for the purpose herein set forth.

page_text: Third. In combination with an improved instrument for regulating electro motive
force and current the use of the spring friction pulley N substantially as and for the
purpose herein set forth and shewn upon the drawings.
Dated this 13th day of September 1889
GEORGE BARKER,
77, Colmore Row, Birmingham, Agent for Applicants.