IMPROVEMENTS IN THE MEANS OR APPARATUS FOR MEASURING ELECTRIC CURRENTS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Charles Ashley Carus-Wilson at the
Office of the Commissioners of Patents on the 23rd December 1881.
CHARLES ASHLEY CARUS-WILSON of Grenville Place in the County of
Middlesex. "IMPROVEMENTS IN THE MEANS OR APPARATUS FOR MEASURING
ELECTRIC CURRENTS."
My Invention relates to means or apparatus for measuring electric currents and
it consists essentially in the employment for this purpose of a secondary battery
or secondary batteries which, or each of which, is first charged or acted upon by
the current to be measured or a part of it and is then allowed to discharge or run
down or has its current reversed, these alternate actions being repeated and made
to communicate motion to or regulate the action of any given counting or
integrating apparatus.
The Invention may be carried out in various ways some of which I will now
proceed to describe.
According to one method a secondary battery is acted upon by the current to be
measured or a part of it and when this battery is fully charged or charged to a
certain predetermined amount the current to be measured is cut off and reversed
so that it proceeds to charge the battery in the other direction or rather to undo
what it has just done; this action keeps repeating itself and each reversal
communicates motion to or regulates the action of the counting or integrating
machine. The rate of such notion being proportional to the strength of the
current.
According to another method a secondary battery is charged by the current to be
measured and when fully charged or charged to a certain predetermined amount
the current is cut off and the battery is allowed to discharge itself by making
suitable contacts; and when discharged it again makes contact to charge, and so
on, the respective actions actuating or regulating the counting apparatus.
According to another method two or more secondary batteries are employed;
when one of them, say the first is fully charged or charged to a certain
predetermined amount by the current to be measured it cuts off circuit and makes
ID 471

page_text: circuit to the second battery, at the same time permitting the first to discharge or
run itself down or reversing the current in it, and so on through the series of
batteries, the respective actions actuating or regulating the counting apparatus.
According to another method a second battery is charged by the current to be
measured and the circuit through the battery is automatically broken at certain
intervals, the amount of electricity stored therein being measured and recorded by
any suitable counting or integrating apparatus; while the registration is being
effected another secondary battery may be charged and then treated in the same
way so that a continuous registration of the amount which has passed may be
obtained. Any convenient number of secondary batteries may be used in this way.
According to another method a secondary battery or one of two or of a series of
secondary batteries is charged by the current to be measured and the current is
automatically broken at fixed intervals such intervals being determined by the
amount stored; and when the circuit is broken a circuit may be made to another
battery of the series, the first battery being permitted to discharge or run itself
down or having the current in it reversed, and so on through the series of batteries
the respective actions actuating or regulating the counting apparatus.
According to another method one or more secondary batteries are charged in
succession by the current to be measured, the rate of charging (consequent upon
the amount of current passing) producing a motion which is stopped in cach
battery-at-a-certain-predetermined or other point and the current is reversed or
else cut off entirely or changed to another battery; while this other battery is
being charged the first is brought to its original state by the reversal of the
current in it or by being allowed to run down. The respective actions actuate or
regulate the counting apparatus as before. If in place of such batteries the
current is simply allowed to decompose liquids the products of decomposition may
be allowed to recombine and thus produce an electric current or they may be
permitted to escape..
According to another method a secondary battery or one of a series of secondary
batteries is charged by the current to be measured and the contact is broken at
intervals such breaking of contact being regulated by mechanism and capable of
variation; and the mechanism may be controlled by any apparatus which has
action varying with the resistances that may be in circuit from time to time.
For instance, clockwork or other motion, may be employed controlled by the action
of a galvanometer, which galvanometer may be arranged with resistances in the
meter, as a Wheatstone's bridge or differential coils, and it being so contrived that
when the galvanometer is deflected, consequent upon an increase or decrease of
resistance in circuit, an auxiliary current is brought into play which actuates
mechanism to put in more or less resistance in the meter to balance that in the
circuit, the result being that a movable piece can be got to have a certain definite
position for a certain resistance in circuit, and by altering the proportion of the
resistances in the meter, the apparatus can be made more or less sensitive and the
measuring capacity of the meter be thus increased or decreased.
This arrangement may also be employed in a meter wherever it is necessary to
obtain an action movement or position varying with the resistance in circuit.
According to another method one or more secondary batteries are employed
charged by the current to a certain degree to actuate mechanism, which mechanism
is in its turn controlled by the amount of current passing so as to register
or record it; this may take the place of clockwork in a meter which has to be
wound up, and it may be so arranged that when the battery actuating the
mechanism has nearly run out it may be charged again while another is, or is not,
taking its place. In order that a "short circuit" in the circuit may not injure
apparatus in the meter, I introduce into the meter a short circuit detector,
which is so arranged that upon a "short circuit" occurring, the main current is at
once broken cutting off the current to the district or position where the short
current has occurred, and keeping the current cut off, at the same time rendering
some visible sign that a short circuit has occurred, as a handle thrown out or disc

page_text: moved &c, and so that the current cannot again flow until the detector in the
meter is released.
When it is required to register the variations in, or the degree of, the electro
motive force between any two conductors, or to record such variations at different
times, either in connection with a current ineter or separately, any of the above
arrangements that are suitable might be used, provided the current between the
two conductors be passed through a fixed resistance. For instance the current
may be passed from a main to an earth through a fixed resistance and be made
to act upon
a secondary battery, such action to be suspended from time to
time, and the amount of the action that has taken place recorded so as to indicate
the variations in the electro-motive force, another battery being acted upon
meanwhile; such apparatus may also be employed where it is necessary to
introduce the variations in the electro motive force as a function in any current
integrating apparatus, the indications above referred to, instead of registering
themselves automatically, causing variations in the action of other mechanism,
which action may already be integrating with respect to one or more variables.
In any of the above apparatus the secondary batteries may be charged and
reversed or allowed to run down under different circumstances, for instance
through different resistances; thus a battery may be charged through x ohms
and allowed to run down short circuited or vice versa, and the time of charging
and reversing or running down may be made to vary in this manner, either
arbitrarily or automatically.
By the term secondary battery as herein used I mean any combination or
combined employment, of substances which vary their condition under the action
of an electric circuit and are capable of resuming or returning to their original
state or condition when such current is cut off and generating an electric current,
whilst that secondary or reverse action is taking place.
In any of the methods described either the main current to be measured or part
of it may be employed.