Improvements in Apparatus for Measuring Electric Currents.
Year: 1891

page_text: Date of Application, 24th July, 1891
Complete Specification Left. 23rd Apr.. 1892-Accepted. 23rd July. 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Measuring Electric Currents.
I, HERMANN ARON Ph.D. of 6 Lützowstrasse, in the City of Berlin and
Kingdom of Prussia, German Empire, do hereby declare the nature of this
invention to be as follows:-
My invention relates to an improvement in apparatus for measuring electric
currents of that class in which an electric motor, worked by the combination of a
main circuit and a shunt circuit, is employed for measuring the supply of current.
All apparatus hitherto employed of this class are subject to a great disadvantage
which consists in that they absorb too much of the electrical energy, partly by
causing a considerable loss of tension in the circuit of the main current, and partly
by consuming a too great amount of current in the shunt circuit.
The loss of tension in the main circuit, with most of the apparatus of the class
described, amounts to 0.5 up to 10 volt, when the maximum volume of current is
passing through the circuit.
While the loss of energy is a considerable disadvantage, a still greater dis-
advantage, connected with the said class of apparatus, is caused by the variability
of tension according to the greater or less amount of current employed. Such
differences of tension, being added to the inevitable variations of tension which
occur besides, form a material and greatly objectionable deterioration of the whole
system, and are therefore to be avoided.
The considerable consumption of current in the shunt circuit, however, does not,
in fact, materially influence the quality of the system, but, owing to the amount of
energy lost in the present kind of motor counting-apparatus, comes prominently
into consideration, since such amounts to about to ampère in the shunt circuit
and since this loss of energy continues all along, even if there be no consumption
of current in the main circuit.
A consumption or loss of 16 ampère in 24 hours is equal to a loss of 2.4 ampère-
hours per diem. Now, as an electrical light system of 12 ampères may be taxed
to supply, in the average of year, 8 ampères during three hours per diem, equal
to 24 ampère-hours per diem, the consumption of current in the shunt-circuit
alone would amount to 10 per cent. of the total supply, a proportion which, without
doubt, is very disadvantageous and objectionable.
To obviate these inconveniences, I connect, according to my present invention,
the shunt-circuit of the motor-counting apparatus to suitable mechanism, such as a
clock-work or wheel-work, which closes the shunt circuit during suitable intervals,
for instance, during intervals of one or two minutes, for a very short period, say t
or second, after which the current is again interrupted. At each intermittent
closing of the circuit, the motor receives strong impulses, which impart motion to
the same, while, in the intervals, owing to the consumption of energy through
mechanical or magnetical friction or any other passive resistance, the motion of the
motor is being slowed down and either stopped or retarded till the next impulse
gives it a fresh start.
Now, as the consumption of current during such intervals will scarcely undergo
material variations, and, as such accidental variations which may occur will be
compensated in the total sum, the intermittent motion of the motor is quite as
applicable for registering the supply of current, as the constant motion which the
motor would receive if my said invention were not applied.
Supposing now that the shunt-circuit of the motor becomes closed, for instance,
for second in every minute, it will be evident that, under the conditions afore-
stated, the consumption of current in the said shunt-circuit will amount to only

page_text: 1 of the consumption in constant motion. This consumption of current, indeed,
would be so trifling that, without losing a too great amount of current in the
shunt-circuit, the strength of such current could be materially increased, the more
so as, owing to the very short duration of the current, the conductors will not
materially be heated.
By increasing the strength of current in the shunt-circuit, for instance, from
ampère to 2 ampères, and by closing the current for second in every minute,
the total loss of energy in the shunt-circuit, would still only be 0.2 ampère-hours
in the course of a day, that is, the twelfth part of the loss which, according to the
above statement, is experienced in a shunt-circuit of ampère and a motor with
constant, motion. A shunt-circuit of 2 ampères would give impulses to the motor,
at short intervals of 20 fold strength when compared with a current of 1 ampère,
but, as such vigorous impulses are by no means required, the strength of current in
the shunt-circuit may be considerably reduced, say to the fifth part of 2 ampères,
as above proposed. This reduction may preferably be performed by choosing
the fifth part of the ampère-turns for the main current. By this means, the
loss of tension in the main current is equally reduced to the fifth part, a
rate which is no further objectionable. The strength of current in the shunt-
circuit, thus being reduced to 04 ampère, will still give impulses of 4-fold
strength, as compared with a current of 10 ampère, and by such sufficiently
strong impulses, any checking influences, or resistances, will be much easier
overcome and work no undue effect. In consequence, by the improved apparatus
of my invention, not only a considerable economy of current will be obtained, but
the working will be more reliable and secure.
Dated this 23rd day of July 1891.
WM. P. THOMPSON & Co.,
Agents for Applicant.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Measuring Electric Currents.
I, HERMANN ARON, Ph.D. of 6 Lützowstrasse, in the City of Berlin and
Kingdom of Prussia, German Empire, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
My invention relates to an improvement in apparatus for measuring electric
currents of that class in which an electric motor, worked by the combination of a
main circuit and a shunt circuit, is employed for measuring the supply of current.
All apparatus hitherto employed of this class are subject to a great disadvantage
which consists in that they absorb too much of the electrical energy, partly by
causing a considerable loss of tension in the circuit of the main current, and partly
by consuming a too great amount of current in the shunt circuit.
The loss of tension in the main circuit, with most of the apparatus of the class
described, amounts to 0-5 up to 10 volt, when the maximum volume of current is
passing through the circuit.
While the loss of energy is a considerable disadvantage, a still greater dis-
advantage, connected with the said class of apparatus, is caused by the variability
of tension according to the greater or less amount of current employed. Such
differences of tension, being added to the inevitable variations of tension which
occur besides, form a material and greatly objectionable deterioration of the whole
system, and are therefore to be avoided.
The considerable consumption of current in the shunt circuit, however, does not,
in fact, materially influence the quality of the system, but, owing to the amount of
energy lost in the present kind of motor counting-apparatus, comes prominently
into consideration, since such amounts to about ampère in the shunt circuit and

page_text: since this loss of energy continues all along even if there be no consumption of
current in the main circuit.
A consumption or loss of 15 ampère in 24 hours is equal to a loss of 24 ampère-
hours per diem. Now, as an electrical light system of 12 ampères may be taxed
to supply, in the average of a year, 8 ampères during three hours per diem, equal
to 24 ampère-hours per diem, the consumption of current in the shunt-circuit alone
would amount to 10 per cent. of the total supply, a proportion which, without
doubt, is very disadvantageous and objectionable.
To obviate these inconveniences, I connect, according to my present invention,
the shunt-circuit of the motor-counting apparatus to suitable mechanism, such as
a clock-work or wheel-work, which closes the shunt circuit during suitable
intervals, for instance, during intervals of one or two minutes, for a very short
period, say or second, after which the current is again interrupted. At each
intermittent closing of the circuit, the motor receives strong impulses, which
impart motion to the same, while, in the intervals, owing to the consumption of
energy through mechanical or magnetical friction or any other passive resistance,
the motion of the motor is being slowed down and either stopped or retarded till
the next impulse gives it a fresh start.
Now, as the consumption of current during such intervals will scarcely undergo
material variations, and, as such accidental variations which may occur will be
compensated in the total sum, the intermittent motion of the motor is quite as
applicable for registering the supply of current, as the constant motion which the
motor would receive if my said invention were not applied.
Supposing now that the shunt-circuit of the motor becomes closed, for instance,
for second in every minute, it will be evident that, under the conditions afore-
stated, the consumption of current in the said shunt-circuit will amount to only
240 of the consumption in constant motion. This consumption of current, indeed,
would be so trifling that, without losing a too great amount of current in the shunt-
circuit, the strength of such current could be materially increased, the more so as,
owing to the very short duration of the current, the conductors will not materially
be heated.
By increasing the strength of current in the shunt-circuit, for instance, from
ampère to 2 ampères, and, by closing the current for second in every minute,
the total loss of energy in the shunt-circuit would still be only 0-2 ampère-hours
in the course of a day, that is, the twelfth part of the loss which, according to the
above statement, is experienced in a shunt-circuit of to ampère and a motor with
constant motion. A shunt-circuit of 2 ampères would give impulses to the motor,
at short intervals of 20 fold strength when compared with a current of to ampère,
but, as such vigorous impulses are by no means required, the strength of current in
the shunt-circuit may be considerably reduced, say to the fifth part of 2 ampères,
as above proposed. This reduction may preferably be performed by choosing the
fifth part of the ampère-turns for the main current. By this means, the loss of
tension in the main circuit is equally reduced to the fifth part, a rate which is no
further objectionable. The strength of current in the shunt-circuit, thus being
reduced to 04 ampère, will still give impulses of 4-fold strength as compared
with a current of 10 ampère, and, by such sufficiently strong impulses, any
checking influences or resistances will be much more easily overcome and work
no undue effect. In consequence, by the improved apparatus of my invention, not
only a considerable economy of current will be obtained, but the working will be
more reliable and secure.
The accompanying sheet of drawings illustrates, as an example, one modification
of the apparatus described in the foregoing Specification.
A, is the armature forming part of a motor, driven by the combination of an
electric main-circuit and a shunt circuit, as known in apparatus of the kind for
measuring electric currents; B is the dynamo-machine, or source of electricity;
C are the lamps or translating devices worked by the main circuit, which passes
constantly through ports 4-5.

page_text: The shunt-circuit of the motor is indicated by 1, 2, 3, 4, the said circuit being
interrupted as at a¹, a³, by which letters I have indicated contact springs, or other
suitable contacts, connected with the terminals a³, a' of the interrupted circuit.
D is the dial of any suitable clock-work, on the axis b of the second wheel, a
disc d of conductive material is mounted, the greater part of which disc, at the
circumference is covered by a suitable insulating material e such as ebonite or the
like. Such disc d, making one revolution in every second, slides on the two contact
springs a a, which, by their elasticity, bear against its circumference. While
the insulating portion e is sliding on the said springs a', a³, the shunt
circuit 1, 2, 3, 4, will be open, but, while the conductive portion e' connects the
two springs a, a, as shown, the said shunt-circuit will be closed. The motor
accordingly receives the electrical impulsion only during that part of a minute
where the conductive portion e' of disc d connects the contact-springs a¹, a². The
shunt circuit, when closed, passes from 1 to a¹, to e¹, to a³, to 2, to 3, to 4. The
lamps C are lighted without interruption through the main circuit passing
through 4-5.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
In a motor-counting-apparatus for measuring electric currents, the combination,
with a suitable motor worked by the combination of a main and a shunt-circuit, of
suitable mechanical means by which said shunt-circuit is closed and opened at
suitable intervals, thereby changing the continuous motion of the motor into a
periodical motion, substantially as and for the purpose described.
Dated this 22nd day of April 1892.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.