IMPROVEMENTS IN AN ELECTRICAL CURRENT MEASURER
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, HENRY FRANCIS JOEL, of 44 Lavender Grove, Dalston, London, in the
County of Middlesex, Electrical Engineer, do hereby declare the nature of my
Invention for "IMPROVEMENTS IN AN ELECTRICAL CURRENT MEASURER," to be
as follows:-
My invention relates to the construction and regulation of a Galvanometer, or
Electrical Current measurer. I construct a Galvanometer with a broad band of
copper as the conductor, and a short magnetic needle of about the same length as
the width of the copper band, I pivot the needle in a separate frame over the
centre of the conductor, and mount the whole upon a suitable base board. To the
pivot of the needle I fix a pointer with its under end overweighted by an adjustable
screw bob. The magnet and pointer in their normal condition hang perpendicularly
with their axis in a line with the centre of the conductor. I have found that with
such a combination, the tangent of the angle of deflection is a measure of the
ampere current passing through the conductor, and if the screw bob is raised or
lowered the deflection for the same current is increased or decreased.
:
To adjust and regulate this ampere meter, I move the needle towards or away
from the conductor, either by sliding it along the pivot, or alternatively by moving
the needle and frame in which it is pivoted, backwards or forwards by means of a
screw; in this latter case I attach a pointer to the screw and with a scale regulate
the adjustment.
I also adjust or calibrate the deflection of the needle by means of a small jockey
counterweight which I slide up or down upon the pointer itself.
I surround the magnetic needle with a ring of soft iron which whilst . not
preventing the movement of the needle acts as an armature, and also as a damper
to the motion of the needle, at the same time it screens the needle from any outside
disturbing magnetic influence.
Dh: 10th of 1901.

page_text: COMPLETE SPECIFICATION.
I, HENRY FRANCIS JOEL of 44 Lavender Grove, Dalston, London, in the
county of Middlesex, Electrical Engineer, do hereby declare the nature of my
invention for IMPROVEMENTS IN AN ELECTRICAL CURRENT MEASURER, and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:—
In the accompanying drawing Fig 1, is a plan Fig 2, a section of my complete
Electrical Current Measurer, Figs 3, and 4, are respectively a plan and section of
. details. I construct a galvanometer with a broad band of copper C, as the
conductor, and a short magnetic needle N, of about the same length as the width of
the copper band C. I pivot the needle N, in a separate frame F, over the centre of
the conductor and mount the whole upon a suitable base board B. To the pivot of
the needle P, I fix a pointer R, with its under end over weighted by an adjustable
screw bob S, The magnet N, and pointer R, in their normal condition hang
perpendicular with their axis in a line with the centre of the conductor C. I have
found that with such a combination, the tangent of the angle of deflection is a
measure of the Ampere current passing through the conductor O and if the screw
'bob S is raised or lowered the deflection for the same current is increased or
decreased.
'
To adjust and regulate this Ampere meter, I move the needle N, (see Fig 1)
towards or away from the conductor C, either by sliding it along the pivot P or
alternatively by moving the needle and frame D in which it is pivotted, (see Figs 3
a plan and Fig 4 a section) backwards or forwards by means of a screw E, in this
latter case I attach a pointer e, to the screw and with a scale regulate the
adjustment.
I also adjust or calibrate the deflection of the needle by means of a small jockey
counter weight J, (see Fig 1) which I slide up or down upon the pointer R itself, in
one position the pointer would indicate 100 Amperes, and in the other 200 Amperes
over the scale, as shewn.
I surround the magnetic needle with a ring of soft iron M (see Figs 1 and 2)
which whilst not preventing the movement of the needle N acts as an armature,
and also as a damper to the motion of the needle, at the same time it screens the
needle from any outside disturbing magnetic influence.
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 :-
1st A Tangent Electrical Current Measurer, having a conductor C, magnetic
needle N, pointer R, and adjustable counterweight S, substantially as shewn and
described.
2nd The method of regulating the Meter by moving the magnetic needle to or
from the conductor substantially as shewn and described.
'
3rd The method of altering the deflection of my Meter by moving a jockey
weight on the pointer, substantially as shewn and described..
4th Protecting the magnetic needle of the Meter from disturbing magnetic
influences, by means of a ring of soft iron, substantially as shewn and described.
.
Dated this 11th day of October 1884.