A Method of Gauging Electric Currents and Apparatus for that Purpose.
Year: 1886

page_text: Date of Application, 20th Apr., 1886.
Complete Left, 20th Jan., 1887.
Complete Accepted, 22nd Feb., 1887.
A Method of Gauging Electric Currents and Apparatus
for that Purpose.
1, STANLEY CHARLES CUTHBERT CURRIE of No. 75 Jermyn Street in the County of
Middlesex, Electrical Engineer, do hereby declare the nature of this invention to be
as follows:-
My invention relates to means of gauging the quantity or intensity of an electric
current passing through a conductor, which I effect in the following manner.
Within a stationary. piece, or between several pieces of soft iron I mount. free to
swing on a pivot, or to slide, another piece of soft iron, and I surround the whole by
a coil or coils through which the current to be gauged or a portion thereof passes.
Owing to the passage of the current through the coil, all the pieces of iron are
magnetised, the adjacent poles of each being made of like polarity. Thus a repulsive
force acts on the moveable piece causing its poles to move away from the stationary
poles, in opposition to a weight or spring, and the amount of movement thus caused,
as shewn by an index, gauges the quantity or intensity of the passing current accord-
ing as the coil has low or high resistance.
Instead of using a weight or spring for resisting the repelling movement, a float
in mercury or other liquid may be employed, and this float may be so shaped as to
give by its greater or less immersion readings which are convenient for estimation.
ABEL & IMRAY,
28, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: A Method of Gauging Electric Currents and Apparatus
for that Purpose.
I, STANLEY CHARLES CUTHBERT CURRIE of No. 75 Jermyn Street, in the County
of Middlesex, Electrical Engineer, 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 :-
My invention relates to means of gauging the quantity or intensity of an electric
current passing through a conductor, which I effect in the following manner.
Within a stationary piece, or between several pieces of soft iron I mount free to
swing on a pivot, or to slide, another piece of soft iron and I surround the whole by
a coil or coils through which the current to be gauged or a portion thereof passes.
Owing to the passage of the current through the coil, all the pieces of iron are
magnetised the adjacent poles of each being made of like polarity. Thus a repulsive
force acts on the moveable piece causing its poles to move away from the stationary
poles, in opposition to a weight or spring, and the amount of movement thus caused
as shewn by an index gauges the quantity or intensity of the passing current
according as the coil has low or high resistance.
Instead of using a weight or spring for resisting the repelling movement, a float in
mercury or other liquid may be employed, and this float may be so shaped as to give
by its greater or less immersion readings which are convenient for estimation.
The accompanying drawings shew various forms in which the parts may be
arranged to operate as described.
In Figure 1 which is an elevation and Figure 2 which is a plan, an iron tube A
surrounded by a coil has fitted to slide longitudinally within it a tube of brass or other
non-magnetic material containing an iron core B. When a current passes through
the coil, both the tube A and the core B become magnetised with similar polarity.
The core is therefore repelled upwards giving an indication on a scale S. In Figure 3
which is a plan and Figure 4 which is a section on Z. Z, there are two iron bars A, A,
and mounted on a vertical axis, a third bar B which can oscillate between them. The
whole is enclosed in a casing wound round by a coil, and the axis of the bar B carries
an index. When a current passes through the coil, the two bars A and the bar B
become similarly magnetised so that the pole ends of Bare repelled, in opposition to
a spring V, and the index is thus moved along the scale. Figure 5 is a plan and
Figure 6 a section shewing a compact arrangement of the parts whereby the indications
are received on a scale of equal divisions.
Within a bobbin B which has a central cylindrical space I fix a piece of soft iron M,
which in section is a segment of a circle somewhat less than a semicircle. On a
vertical axis A which is eccentric to the bobbin, I fix arms carrying a cylindrical
piece of soft iron. The upper part of the axis A has fixed to it the inner end of a
volute spring V, the outer end of which is attached by a pin to a disc D that can be

page_text: turned more or less round by a key applied at K so as to adjust the force of the
spring in pressing C more or less forcibly against the flat face of M. To the axis A
is fixed an index I which points to degrees on a graduated scale S that can be seen
through glass G. The conducting wires convey the electrical current that has to be
gauged or a known fraction thereof, to posts fixed in a block E of insulating material
such as vulcanite, and connected to the coil of the bobbin B.
When a current passes through the coil the piece M and the piece C are both
rendered magnetic, each with similar poles at its ends, thus, if the upper end of M
is N, so also is the upper part of C, and conversely. Owing to the contiguity of the
similar poles the piece Cis repelled from Mand the index I is caused to move along the
scale S. At the same time, the piece C is influenced by the coil of the hobbin, so
that when it moves away from M, becoming repelled with force decreasing very
rapidly as it departs, it becomes attracted towards the side of the bobbin with a
force increasing as it approaches F. By properly selecting the position of the axis A
relatively to the centre of the bobbin, the result of the two forces, the magnetic
repulsion of M and the attraction of the side of the bobbin nearest to C, may be made
such that equal movements of the index I over the scale S correspond very nearly
with equal amounts of current in the hobbin coil, and consequently the scale S may
be graduated with equal divisions.
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 :-
1. The construction and use of an electric gauge wherein a stationary and a
moveable piece of iron are arranged within a coil so that they both become similarly
magnetised when an electrical current passes through the coil, and the moveable piece,
being thus repelled in opposition to a spring or other adjustable resistance, serves by
its movement to gauge the current, substantially as herein described.
2. In an electric gauge constructed and arranged substantially as described with
reference to Figures 5 and 6, the combination of the coiled bobbin B, the piece of
iron M fixed at one side and the piece C mounted on an index axis which is eccentric
to the bobbin and is acted on by an adjustable spring V.
ABEL & IMRAY,
Agents for the Applicant.