Improvements in Apparatus for Indicating and Recording Electric Supply.
Year: 1895

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c., Act, 1883), as allowed
by the decision of the Comptroller General of the 11th day of October 1897.
Date of Application, 27th Nov., 1895
Complete Specification Left, 28th Sept., 1896--Accepted, 7th Nov.,
1896
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Indicating and Recording Electric
Supply.
I, WILLIAM THOMSON, BARON KELVIN or LARGS, Professor of Natural
Philosophy in the University of Glasgow, North Britain, do hereby declare the
nature of this invention to be as follows:-
In the electric supply meter described in ny Specifications Nos. 18436,
A.D. 1891, and 24,471, A.D. 1893, I find that a sufficiently uniform scale for
practical purposes can be obtained with a wire or thin rod of soft iron without the
solenoid of fine insulated wire around it, by giving a proper configuration to the
fixed solenoid to produce a stronger magnetic field in the upper part of its hollow,
and a properly graded field throughout. When the maximum current to be
ineasured is less than 20 amperes the desired grading of the field may be given by
greater and less number of turns of insulated wire in different parts of the solenoid.
For stronger currents the solenoid may be made with a single turn of the conductor
round each part all over, but with the successive convolutions closer and less close
in different parts, and to avoid heating the conductor may be made thicker in the
parts where the convolutions are less close. When the strongest current to be
measured is 1000 amperes or more, instead of the solenoid I use a broad ribbon
of copper bent through 180 degrees as sharply as may be, so that the current enters
and leaves in opposite parallel directions. Or I use a straight ribbon conveying
the current in one direction, and in such case I use, instead of the straight iron
rod, a horse-shoe of soft iron wire with its ends on the two sides of the ribbon. The
proper gradation of the field may be obtained by making the ribbon thinner in
some places and thicker in others, or by making saw-cuts or holes in different parts
of the ribbon, so as partially to obstruct the current in the places where the
magnetic field is to be less strong.
The soft iron plunger is hung on the lower end of a spiral spring, the upper end
of which in some cases is hung from the lower end of an adjusting screw, and in
some cases from one end of the beam of an ordinary balance prevented by a stop
from sinking below a certain limit, or controlled by adjustable spring stops. The
reason for sometimes suspending it on the beam of a balance is to give sufficient
sensibility for the smallest currents to be measured; and for this purpose an
adjustment of the centre of gravity of the beam is provided.
With a simple soft iron wire for the plunger instead of the suspended electro-
magnet of my supply meters as hitherto made, the separate recording har becomes
unnecessary, and I produce the record by causing the clockwork to lift the plunger
itself simply instead of the recording pin.
A farther improvement consists in causing the recording pin or plunger to be
pressed between an idle roller and the roller of the recording train by keeping the

page_text: axis of the idle roller fixed, and bringing the other into contact by a motion of the
framework of the recording train. This improvement has the advantage of
preventing any tendency to drive the recording roller backwards by the descent of
the recording pin or plunger.
For keeping the clockwork going I use a bar of soft iron which is lifted by a
current through a fixed solenoid of fine wire, and is allowed to descend and serve
At the end of its
as driving weight by its breaking the circuit during its ascent.
descent, or a little before it, it re-makes the circuit by pushing down, or by letting
fall a contact piece, and is again lifted by the current. I simplify the clockwork
very much by omitting the two ratchet wheels and the maintaining power of the
apparatus described in my Specification No. 24,471, A.D. 1893, and using a soft
flexible ribbon over a brass drum to bear the iron bar at one end, and having its
other end attached to an arm provided with a cam weighted or pressed by a spring
very lightly against a smooth rim rigidly connected with the escapement wheel, the
cam being so shaped as to allow motion relatively to the rim in one direction and
prevent it in the other. I may also use a cam with a fixed axis pressing lightly on
the wheel and so shaped as to prevent it running backwards.
In some cases where it is desired to show the maximum current which has
passed through the meter during a certain period I employ the plunger
above described to operate an indicator. The indicator may be a light inarker
kept in position on the plunger by pressure of a like spring. As the plunger
is drawn into the solenoid the marker comes in contact with a fixed stop and
is slided along the plunger a greater or less distance according to the amount
of current being used. The marker remains in the position to which it is moved
and thus indicates the maximum amount of current which has passed through the
meter. Instead of the sliding marker above described I may use a paper strip
attached to the plunger, and provide a tube containing ink or other coloured liquid
in the centre of the solenoid, into which the plunger with paper attached is drawn.
The length of paper coloured by the liquid will indicate the maximum current
which has passed through the meter. Or I may use other forms of-indicator; as
for example the plunger may be drawn into a tube full of oil or other liquid, and
as it is drawn in, the oil or other liquid may be caused to flow into a measuring
vessel. The quantity of liquid which overflows into the measuring vessel indicates
the maximum current passed through the meter; or I may employ a marker
attached to a string passing over a pulley and balanced by a disc hanging in a
vessel containing oil or other viscous fluid. By means of a suitable connection
the plunger as it is drawn into the solenoid will draw the marker down and
leave it in position indicating the maximum current passed through the meter.
In some cases I use the indicator for maximum current, and omit the recording
clockwork.
BOTTOMLEY & LIDDLE,
154 St. Vincent Street, Glasgow, Applicant's Agents.
Improvements in Apparatus for Indicating and Recording Electric
Supply.
I, WILLIAM THOMSON, BARON KELVIN OF LARGS, Professor of Natural
Philosophy in the University of Glasgow, North Britain, 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 :-
In the electric sunnly meter described in my Specifications Nos. 18436 A.D. 1891

page_text: and 24471 A.D. 1893 I find that a sufficiently uniform scale for practical purposes
can be obtained with a wire or thin rod of soft iron without the solenoid of fine
insulated wire around it by giving a proper configuration to the fixed solenoid to
produce a stronger magnetic field in the upper part of its hollow and a properly
graded field throughout. When the maximum current to be measured is less
than 20 amperes the desired grading of the field may be given by greater and less
number of turns of insulated wire in different parts of the solenoid. For stronger
currents the solenoid may be made with a single turn of the conductor round each
part all over but with the successive convolutions closer and less close in different
parts, and to avoid heating the conductor may be made thicker in the parts where
the convolutions are less close. When the stronger current to be measured
is 1000 amperes or more instead of the solenoid I use a broad ribbon of copper
bent through 180 degrees as sharply as may be, so that the current enters and
leaves in opposite parallel directions. Or I use a straight ribbon conveying the
current in one direction, and in such case I use, instead of the straight iron rod a
horse shoe of soft wire with its ends on the two sides of the ribbon. The proper
gradation of the field may be obtained by making the ribbon thinner in some
places and thicker in others or by making saw-cuts or holes in different parts of.
the ribbon so as partially to obstruct the current in the places where the magnetic
field is to be less strong.
The soft iron plunger is hung on the lower end of a spiral spring, the upper end
of which in some cases is hung from the lower end of an adjusting screw and in
some cases from one end of the beam of an ordinary balance prevented by a stop
from sinking below a certain limit, or controlled by adjustable spring stops. The
reason for sometimes suspending it on the beam of a balance is to give sufficient
sensibility for the smallest currents to be measured, and for this purpose an
adjustment of the centre of gravity of the beam is provided.
With a simple soft iron wire for the plunger instead of the suspended electro-
magnet of my supply meters as hitherto made, the separate recording bar becomes
unnecessary and I produce the record by causing the clockwork to lift the plunger
itself simply instead of the recording pin.
A further improvement consists in causing the recording pin or plunger to be
pressed between an idle roller and the roller of the recording train by keeping the
axis of the idle roller fixed and bringing the other into contact by a motion of
the framework of the recording train. This improvement has the advantage of
preventing any tendency to drive the recording roller backwards by the descent
of the recording pin or plunger.
For keeping the clockwork going I use a bar of soft iron which is lifted by a
current through a fixed solenoid of fine wire and is allowed to descend and serve as
driving weight by its breaking the circuit during its ascents. At the end of its
descent, or a little before it, it re-makes the circuit by pushing down, or by letting
fall a contact piece, and is again lifted by the current. I simplify the clockwork
very much by onitting the two ratchet wheels and the maintaining power of the
apparatus described in my Specification No. 24471 A.D. 1893 and using a soft
flexible ribbon over a brass drum to bear the iron bar at one end and having its
other end attached to an arm provided with a cam weighted or pressed by a spring
very lightly against a smooth rim rigidly connected with the escapement wheel,
the cam being so shaped as to allow motion relatively to the rim in one direction
and prevent it in the other. I may also use a cam with a fixed axis pressing
lightly on the wheel and so shaped as to prevent it running backwards.
In some cases where it is desired to show the maximum current which has passed
through the meter during a certain period I employ the plunger above described
to operate an indicator. The indicator may be a light marker kept in position on
the plunger by pressure of a light spring. As the plunger is drawn into the
solenoid the marker comes in contact with a fixed stop and is slided along the
plunger a greater or less distance according to the amount of current being used.
The marker remains in the position to which it is moved and thus indicates the

page_text: maximum amount of current which has passed through the meter. Instead of the
sliding marker above described I may use a paper strip attached to the plunger
and provide a tube containing ink or other coloured liquid in the centre of the
solenoid into which the plunger with paper attached is drawn. The length of paper
coloured by the liquid will indicate the maximum current which has passed through
the meter. Or I may use other forms of indicator; as for example a marker attached
to a string passing over a pulley and balanced by a disc hanging in a vessel containing
oil or other viscous fluid. By means of a suitable connection the plunger as it is
drawn into the solenoid will draw the marker down and leave it in position indicating
the maximum current passed through the meter.
In some cases I use the indicator for maximum current and omit the recording
clockwork.
In order that my invention may be properly understood and readily carried into
efect I have hereunto appended an explanatory sheet of drawings in the several
figures of which corresponding parts are marked with the same letters of
reference.
Figure 1 is an elevation of the instrument for recording electric supply with
qne method of showing the maximum current which has passed through the meter.
As represented in Fig. 1 is the movable soft iron rod or plunger hung on
the lower end of a spiral spring b. The upper end of the spring bis hung from
one end of the beam c of an ordinary balance prevented by a stop d from sinking
below a certain limit. c is an adjustable weight attached to the beam c to allow
of an adjustment of the centre of gravity of the beam. The current to be ineasured
passes through the fixed solenoid e which attracts inwards one end of the soft iron
plunger a. With the simple soft iron wire for the plunger instead of the suspended
electro-magnet of any supply meters as hitherto made, the separate recording bar
becomes unnecessary and I produce the record by causing the clockwork to lift
the plunger itself instead of the recording pin. The counter is similar to that
described in the Specification of my previous Patent No. 18436 A.D. 1891. The
soft iron plunger a moves between the roller g and another roller h. At periodic
intervals of time the roller is, by a revolving cam i caused to press the plunger a
against the roller g and at the same time and actuated by a crank pin attached
to the same cam the end of the rod ; rises up till it comes in contact with the
bar attached to the plunger & and then carries the plunger up with it and causes
the roller of the counter to turn through a space proportional to the amount of
current passing through the fixed solenoid e. The caini is kept revolving by
clockwork. For keeping the clockwork going I use a bar of soft iron which is
lifted by a current through a fixed solenoid m of fine wire and is allowed to descend
and serve as driving weight by its breaking the current during its ascent.
the end of its descent or a little before it remakes the circuit by pushing down the
contact piece n, which completes the circuit of the electro-magnet m and the weight
is again lifted by the current. The weight is hung on one end of a soft flexible
ribbon o Figures 1 and 2, which passes over a smooth brass drum p attached to
the escapement wheel. The other end of the ribbon is attached to an arın g
loosely pivoted to the axis of the escapement wheel. Pivoted to the arm q there
is a cam which rests on the drum p. The cam is shaped so as to allow motion
of the arm relatively to the drum in one direction and prevent it in the other.
Thus while the weight is descending the cam causes the drum p and escapement
wheel to turn round but when the weight is being lifted the cam slips along
the smooth surface of the drum without causing any motion in a backward
direction.
At
The arrangement for indicating the maximum supply consists of a marker 8,
Figure 1, attached to a string t passing over a pulley and balanced by a disc v
hanging in a vessel containing oil or other viscous fluid. The marker s is shown in
Figure 1 near the bottom of its range and not quite touched by the fork k. As
the plunger a is drawn into the solenoid the fork
attached to it pushes the

page_text: marker down and leaves it in a position indicating the maximum current passed
through the meter.
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 :-
1. In the apparatus for indicating and recording electric supply the method
of suspending the soft iron plunger by means of a spiral spring hung from one end
of the beam of a balance, substantially as described and illustrated on Figure 1 of
the accompanying drawings.
2. The simplified arrangement for keeping the clockwork going, substantially
as described and illustrated on Figures 1 and 2 of the accompanying drawings.
3. In apparatus for indicating electric supply the arrangements for indicating
the maximum current which has passed through the instrument, substantially as
described.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.