Improvements in Apparatus for Measuring Electric Ourrents.
Year: 1888

page_text: Date of Application, 8th May, 1888
Complete Specification Left, 31st Jan., 1889
Complete Specification Accepted, 30th Mar., 1889
Improvements in Apparatus for Measuring Electric Ourrents.
I, HERMANN ARON, Ph.D. of Konigin-Augustastrasse 46 Berlin, in the Kingdom
of Prussia, Empire of Germany, do hereby declare the nature of this invention to be
as follows:-
My invention relates to improvements in apparatus for measuring electric currents
of that class, for which I have obtained Letters Patent in Great Britain No. 6770
dated April 24th 1884 and No. 8856 dated June 20 1887.
In apparatus of that kind, the pendulum or regulating spring of a clockwork, or of
two clockworks is subjected to the magnetic influence of a coil or coils through which
the current to be measured is sent, the deviations from the normal time worked by the
influence of the current, affording a true and proportional scale of the force to be
measured, as has been amply explained in the patents aforesaid. In the said patents
I have described and shewn two modifications of differential counters, consisting of
two trains of clock work imparting their movement to a common dial or set of dials
for automatically counting or indicating the amount of deviations of the two clock-
works, occasioned by the magnetic influence of the current.
It will be obvious that the exactness of such instruments or differential counters
depends in a high degree on the synchronism of the clockworks during the time when
there is no influence acted by the current on one of the pendulums or regulating
springs, any deviations between the normal speed of the two clockworks being counted
as if they had been worked by the current, and the amount of current actually spent
will be as much less, or as much greater, than the amount indicated, as the two clock-
works have differed in their normal speed, such difference either adding itself to or
subtracting itself from the difference that has been worked by the current.
My invention, therefore, has for its purpose, first to provide means to secure as
much as practically perfect synchronism of the two pendulums, or regulating springs,
of the two clockworks connected to each other by the differential counter; such
synchronism being established during the time, where there is no influence worked by
the current. From the monent when the current enters, the two pendulums or
regulating springs, are allowed to vibrate independently of each other to produce the
deviations to be counted or indicated on the dial or dials.

page_text: To obtain such synchronism while there is no current passing through the coil or
coils, I provide, according to my invention an extremely small coercion between the
two pendulums sufficient to keep them in exact conformity of vibration such slight
coercion, however, being of no avail from the moment where even the least delivery
of the current influences one of the pendulums or regulating springs and increases the
difference of the duration of the vibrations of the two pendulums or springs.
For acting such coercion, I connect the two pendulums or balances, by an extremely
light and yielding junction, preferably by a light, elastic or non-elastic thread or cord
or a light chain of any suitable material to which thread cord or chain, a small weight
of a few gramms is suspended, automatically adjusting itself at the lowest point of the
slack thread and serving to provide the required slight tension to the thread. By
such means deviations between the normal speed of the two pendulums or regulating
springs, amounting to several vibrations por diem and which deviations may be
occasioned by an unsufficient control, or which cannot be overcome by the controlling
device are entirely compensated. The two pendulums or regulating springs thus
connected to each other work continually in precise conformity with absolute coinci-
dence of their vibrations either in the same or in opposite direction. I have termed
this connection a sympathetic band with reference to the sympathetic pendulums,
which are known to have first been observed by Huyghens.
A connection of this kind may be applied to clock-pendulums of any kind and con-
struction, for instance to torsion-pendulums, and it may be applied with the same
effect to the balance of the regulating springs of clockwork and other regulating
devices.

page_text: Improvements in Apparatus for Measuring Electric Currents.
I, HERMANN ARON, Ph.D. of 40 Königin Augustastrasse Berlin, in the Kingdom
of Prussia, Empire of Germany, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
My invention relates to improvements in apparatus for measuring electric currents
of that class for which have obtained Letters Patent in Great Britain No. 6770
dated April 24, 1884, and No. 8856 dated June, 20, 1887.
In apparatus of that kind, the pendulum, or regulating spring of a clockwork or of
two clockworks, is subjected to the magnetic influence of a coil or coils through which
the current to be measured is sent, the deviations from the normal time worked by
the influence of the current, affording a true and proportional scale of the force to be
measured, as has been amply explained in the patents aforesaid. In the said patents
I have described and shown two modifications of differential counters, consisting of
two trains of clockwork imparting their movements to a common dial or set of dials
for automatically counting or indicating the amount of deviations of the two clock-
works occasioned by the magnetic influence of the current.
It will be obvious that the exactness of such instruments or differential counters
depends in a high degree on the synchronism of the clockworks during the time when
there is no influence acted by the current on one of the pendulums or regulating
springs. Any deviations between the normal speed of the two clockworks which may
exist or occur being counted as if they had been worked by the current, and the
amount of current actually spent will be as much less, or as much greater, than the
amount indicated, as the two clockworks have differed in their normal speed, such
difference either adding itself to or subtracting itself from the difference that has
actually been worked by the current.
My invention, therefore, has for its purpose to provide means for securing as much
as practicable perfect synchronism of the two pendulums, or regulating springs, of the
two clockworks connected to each other by the differential counter, such synchronism
being established during the time when there is no influence worked by the current.
From the moment when the current enters, the two pendulums, or regulating springs,
are allowed to vibrate independently of each other, to produce the deviations to be
counted or indicated on the dial or dials.
To obtain such synchronism, while there is no current passing through the coil or
coils, I provide, according to my invention, an extremely small coercion between the
two pendulums, sufficient to keep them in exact conformity of vibration, such slight
coercion, however, being of no avail from the moment when even the least delivery
of the current influences one of the pendulums or regulating springs, and increases
the difference of the duration of the vibrations of the two pendulums or springs.
For acting such coercion, I connect the two pendulums or balances by an extremely
light and yielding junction, preferably by a very light elastic or non-elastic thread or
cord, or a light chain of any suitable material, to which thread, cord or chain, a
small weight of, say a few gramines, is suspended, automatically adjusting itself at
the lowest point of the slack thread and serving to provide the required slight tension
of the thread. By such means deviations between the normal speed of the two

page_text: pendulums or regulating springs amounting to several. vibrations per diem, which
deviations may have been occasioned by an insufficient control, or which cannot be
overcome by the controlling device, are entirely prevented. The two pendulums or
regulating springs thus connected to each other work normally in precise conformity
with absolute coincidence of their vibrations, either in the same or in opposite
directions. 1 have termed this connection a sympathetic band" with reference to
the sympathetic pendulums which are known to have first been observed by
Huyghens.
In the accompanying drawings, Figure 1 represents the manner in which my said
invention is to be applied to an apparatus for measuring electric currents, said
apparatus consisting of two clockworks arranged side by side in a casing A, and
connected each to a differential counter or dial-train B, as has been fully described in
the specifications of my prior patents No. 67704 and No. 88567. P, P1, are the two
pendulums of the two clockworks, to one of which pendulums P₁, a magnet M is
attached, swinging in proximity to an electric coil C, through which the current to
be measured is sent. A light thread, cord or chain D of any suitable material, elastic
or non-elastic is connected with each of its ends to one of said pendulums P, P', and
if the said thread or cord is non-elastic and slack, a small weight E is suspended to
the said thread, cord or chain to give it a slight tension, which, however, must be
carefully tried, as an excess of draught acting on the two pendulums would cause
them to stop. If an elastic cord, thread or band, of an extremely yielding kind, or a
spiral spring, be employed, the weight E may be dispensed with.
Figure 2 represents, drawn to a larger scale, how the sympathetic band is to be
employed in connection with the regulating springs F of two clockworks. G G are
the two balances of the two clocks, the other parts of which and their connecting gear
with the intermediate dial-train B are not shown in the drawing. To one of said
balances G', a magnet N S is attached under influence of the coil C through which
the current is sent. The thread, cord, band, or chain or elastic connection D may
preferably be secured with its ends, to the shafts of the balances G G¹ or they may as
well be attached to any other part, the spokes or tyre, of the balance wheels. The
slight coercion acted by the said thread, cord, band, or chain D), on the two shafts of
the balance wheels G G will establish synchronism by overcoming slight deviations
of the vibrations in the same manner as with the pendulums as in Figure 1.
A connection of this kind may be applied to clock pendulums of any kind and
construction, for instance to torsion pendulums, or to other regulating devices
employed to control the speed of clockwork.
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 :-
-
In apparatus for measuring electric currents consisting of two clockworks, the
deviations of which occasioned by the influence of the current, are counted to indicate
the amount of current delivered, the combination with the two pendulums, or regu-
lating spring balances, or other equivalent regulating devices, of a readily yielding
elastic or non-elastic thread, cord, band or chain, connecting said pendulums or
regulating devices to each other, for the purpose of establishing synchronism between
the two clockworks while there is no current passing, and of freely allowing the two
clockworks to deviate under the influence of the current, substantially as described.
Dated this 30th day of January 1889.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Filing Agents for the Applicant.