Apparatus for Controlling Electric Currents.
Year: 1896

page_text: Date of Application, 21st July, 1896
Complete Specification Left, 13th Apr., 1897-Accepted, 15th May, 1897
Apparatus for Controlling Electric Currents.
I, JOACHIM ESTRADE of Carcassonne in the Department of Aude, Republic of
France Manufacturer do hereby declare the nature of this invention to be as
follows:-
This invention relates to apparatus for controlling electrical currents and it is
more especially intended to prevent the consumption by a subscriber of more
current than that to which he is entitled.
The principle of the apparatus is based upon the instability of equilibrium of a
lever or balance oscillating on knife edges and having its centre of gravity at such
distance above its fulcrum as is desired to give more or less sensitiveness to the
operation of the apparatus.
This lover is inserted in the circuit of the current and its position may be
controlled or varied by an electro magnet also in the circuit if the current that is
drawn through the circuit increases above that for which the apparatus is adjusted
in order that in such event the movement of the lever will interrupt the circuit and
cause the current to cease or if desired cause it to pass through a shunt resistance
until the cause of the excess of current is removed.
The lever aforesaid may consist of a depending block of soft iron suspended on
the knife edges and having extending from it in one direction a copper rod with an
iron screw passing through its end and in the other direction an arin having its end
turned downwards. On the latter arm and also if desired on the former copper
rod there may a movable counterweight for purposes of adjustment. The end of
the arm and the aforesaid iron screw dip into mercury troughs forming contacts.
Adjacent to the soft iron plate is an electromagnet which may or may not be
adjustable to and from said plate. The whole is enclosed in a dismountable casing
so made that when put together a leaden or other seal may be applied to it so that
it cannot be opened without authority of or undetected by the officials of the
company or persons supplying the electric current.
If a subscriber has contracted for a supply of so many lights say five ten candle
power incandescent lights, the apparatus is set to allow the amount of current
necessary therefor to pass; but if for instance a further five caudle power lamp is
added by the subscriber or if he should substitute a sixteen candle power lamp for
a ten candle power the current will increase setting in movement the lever which
will either bring into action the shunt circuit causing all the lamps to be reduced to
dull red, or will oscillate causing the lamps to be alternately extinguished and
relighted, that is to say so disturbing the light that it will be useless to the
subscriber until the disturbing cause has been removed. A leakage to earth
within the subscribers circuit will also be detected since it will then be impossible
for him to use all his lamps until such leakage is found and corrected.
Duted this 21st day of Jul 1806
HERBERT HADDAN & Co.,
Agents to Applicant.

page_text: I, JOACHIM ESTRADE, of Carcassonne in the Department of Aude, Republic of
France, Manufacturer 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 :-
This invention relates to apparatus for controlling electrical currents and it is
more especially intended to prevent the consumption by a subscriber of more
current than that to which he is entitled.
In the annexed drawing
Fig. 1 is an elevational section, Fig. 2 a horizontal section and Fig. 3 a cross
section on line a a Fig. 1 of the apparatus.
The principle of the apparatus is based upon the instability of equilibrium of a
lever or balance V L P Q L' oscillating on knife edges O and having its centre of
gravity at such distance above its fulcrum as is desired to give more or less
sensitiveness to the operation of the apparatus.
This lever is inserted in the circuit of the current and its position may be
controlled or varied by an electro magnet E also in the circuit. If the current
that is drawn through the circuit A A" A' E B B" BV LP L'B' Z increases
above that for which the apparatus is adjusted, the movement of the lever will
interrupt the circuit and cause the current to cease or if desired cause it to pass
through a shunt resistance until the cause of the excess of current is removed.
The lever aforesaid may consist of a depending block of soft iron P suspended
on the knife edges OO on the pillars S S and having extending from it in one
direction a copper rod L with an iron screw V passing through its end and in the
other direction an arm L' having its end turned downwards. On the latter arm
aud also if desired on the former copper rod there may be a movable counter-
weight Q for purposes of adjustment. The end of the arm L' and the aforesaid
iron screw V dip into mercury troughs B' B forming contacts. Adjacent to the
soft iron plate P is the electro magnet E which may be adjustable by means of
screw and guide c to and from said plate P. The whole is enclosed in a
dismountable casing, consisting of the back plate X with holes 1 2 3 for the
passage of screws for fixing to the wall, of the sides P and the bottom plate F,
the loose top C attached by pins or tenons t¹ and t and having a pin t¹ to pass
through the hinged front X, this pin having a hole in the end through which a
wire may be passed and secured by a leaden or other seal to it so that the case
cannot be opened without authority of or undetected by the officials of the
company or persons supplying the electric current.
Y is a partition with a slot for the passage and guidance of lever arm L and to
keep the mercury fumes from the rest of the apparatus. A similar partition may
be placed to shut off the other mercury cup B.
If a subscriber has contracted for the supply of so many lights say five ten
candle power incandescent lights, the apparatus is set to allow the amount of
current necessary therefor to pass; but if for instance a further five candle power
lamp is added by the subscriber or if he should substitute a sixteen candle power
lamp for a ten candle power the current will increase setting in movement the lever
which will either bring into action the shunt circuit causing all the lamps to be
reduced to dull red, or will oscillate causing the lamps to be alternately extinguished
and relighted, that is to say so disturbing the light that it will be useless to the
subscriber until the disturbing cause has been removed. A leakage to earth within
the subscribers circuit will also be detected since it will then be impossible for him
to use all his lamps until such leakage is found and corrected.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
Apparatus for controlling an electric current, having an oscillatory lever
preferably mounted on knife edges with its extremities dipping into mercury cups,
one of said extremities taking current for an electromagnet and the other for
delivering current so long as the said electromagnet has not, by the attraction of
an armature on the lever, caused the lever to oscillate and break the circuit.
Dated this 13th day of April 1897.
HERBERT HADDAN & Co.,
18, Buckingham Street, Strand, London, Agents to Applicant.