Improvements in and relating to Apparatus for Measuring Electric Currents and for Weighing Bodies or Substances.
Year: 1889

page_text: Date of Application, 4th Sept., 1889
Complete Specification Left, 4th July, 1890-Accepted, 4th Sept., 1890
PROVISIONAL SPECIFICATION.
Improvements in and relating to Apparatus for Measuring Electric
Currents and for Weighing Bodies or Substances.
I, ALFRED LYSTER SHEPARD, of 8 West Kensington Gardens in the County of
Middlesex, Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to apparatus chiefly designed for measuring electric currents.
By my invention I provide an improved device by means of which the quantity
or amount of electric current passing through a circuit, or the strength or intensity
of the said current may be accurately measured and recorded or registered upon a
suitable dial or dials.
My improved apparatus is also applicable for weighing or measuring substances.
In carrying my said invention into practice I provide a suitable beam or balance
lever pivoted at or near its centre to a suitable bracket. Upon one extremity of the
said beam or balance lever is provided a coil of wire electrically connected in a shunt
or derivation from the main circuit. This coil is suspended directly over another coil
which is placed in the main circuit or the circuit which it is desired to measure.
The two coils are so arranged as to be normally in close proximity to each other but
without coming into contact. The other extremity of the said beam or balance lever
is connected to a suitable centrifugal governor provided upon the shaft or arbor of
a small electro-motor arranged to be driven by a shunt or derivation from the main
current, or by current from any suitable source. The circuit to the said electro-
motor when no current passes in the main coil is broken and a suitable contact piece
is provided above the said beam or balance lever, against which the latter is adapted
to bear when oscillated by the varying strength of the current to be measured in
the manner hereinafter described, thus making or completing and interrupting or
breaking the circuit to the said electro-motor. A suitable fly-wheel is preferably
employed for equalizing the motion of the said electro-motor, and maintaining the
rotary motion of the latter during the short intervals or periods during which the
circuit thereto is interrupted or broken. When no current is passing in the circuit
to be measured the beam or balance lever is so adjusted that the contact to the electro
motor is just broken so that the slightest current passing in the main coil will
destroy the equilibrium and press the beam against the said contact, when the motor
will revolve. The operation of the apparatus is as follows that is to say :-The speed
of the electro-motor is so regulated that at any moment the pull of the centrifugal
governor is equal to the pull of the current being measured. Any increase of the said
current will cause the coil upon the extremity of the beam or balance lever to
approach the coil or magnet in the said circuit and thus lower or depress the
extremity of the said beam or balance lever carrying the said coil and consequently
raise or elevate the other extremity thereof and complete the circuit to the electro-
motor. The speed of the latter will then be increased so that the arms carrying the
balls of the governor will fly outwards by centrifugal force and act upon the other
extremity of the said beam or balance lever so as to draw down or depress the same,
and cause the said beam or balance lever to resume its normal position of equilibrium.
The electro-motor is connected by means of tooth gearing or in any other suitable
manner with a dial or dials for registering or recording the number of revolutions of
the electro-motor and from this is deducted the quantity of electric current that has
passed through the said circuit.
By altering the said dial or dials and registering or recording mechanism the
strength or intensity of the said current may be registered or recorded.
My annaratns is also advantageously applicable for weighing substances. In this

page_text: case one extremity of the said beam or balance lever is suitably connected to the
platform upon which the weight is deposited, and the speed of the said electro-
motor is arranged to indicate upon a suitable dial or dials the amount of the said
weight.
Although I have herein before described a convenient and advantageous method of
carrying my said invention into practice it is obvious that I can somewhat modify
the construction of my apparatus without however in any-way departing from the
nature of my said invention.
Dated this 4th day of September 1889.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Apparatus for Measuring Electric
Currents and for Weighing Bodies or Substances.
I, ALFRED LYSTER SHEPARD, of 8 West Kensington Gardens, 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 apparatus chiefly designed for measuring electric currents.
The chief object of my said invention is to provide an improved apparatus by means
of which the quantity or amount of an electric current passing through a circuit or
the strength or intensity of the said current may be accurately and continuously
measured and recorded or registered upon a suitable counter.
An important feature of my said invention consists in the provision of suitable
means whereby the speed of a small electro-motor arranged to be driven by a shunt
or derivation from the main circuit, or by a current from any other suitable source,
will be caused to vary in accordance with the strength or intensity of the current to
be measured, the speed of the said electro-motor balancing mechanically the
strength pull, or intensity of the said current. The electro-motor is connected by
means of tooth-gearing or in any other convenient manner with a suitable counter
for registering or recording the number of revolutions of the said electro-motor, and
from which is deduced the quantity of electric current that has passed through the
said circuit.
My improved apparatus is also advantageously applicable for weighing or measuring
substances.
In the accompanying drawing I have shown how my said invention may be
conveniently and advantageously carried into practice.
Figure 1 is a front elevation illustrating one form of my improved apparatus for
measuring electric currents.
Figure 2 is a front elevation of a portion of a similar apparatus showing a slight
modification hereinafter described.
Like letters indicate corresponding parts throughout these two Figures.
A is a bed plate or base plate, B is an electro-motor, C is the shaft or arbor
thereof which is supported in suitable bearings in a bracket B' secured to the casing
of the said electro-motor, D is one of the field coils, and EE are the brushes, F is the
counter or registering device.
a is a beam or balance lever pivoted at or near its centre by means of a knife
edge a² to a suitable bracket b secured to the bed plate or base plate A. is a coil
of coarse wire supported upon the said bed plate or base plate A, and placed in the
main circuit or the circuit which it is desired to measure. d is another coil of fine
wire electrically connected in a shunt or derivation from the main circuit. The coil d
is secured upon one extremity of a brass or other rod e which passes through a suitable
hole in the centre of the coil c, and the other extremity of which is provided with a
point resting in a countersink at or near one end of the beam or balance lever a.

page_text: in
The said coil d is electrically connected in the said shunt or derivation from the main
circuit in such a manner as not to interfere with the free working or movement
thereof. The two coils are arranged at any suitable distance from each other, the
adjoining faces being opposite poles. ff are spherical or other suitable weights
firmly secured to or formed on arms pivoted at g₁ to a ring or collar / firmly
attached to or formed on a hollow spindle or tube i. j is another ring or collar
arranged to move freely upon the said hollow spindle or tube i. The ring or collar j
is coupled to the arms g by means of connecting rods. This device is substantially
similar to an ordinary centrifugal governor. kis a rod arranged to fit easily in the
said hollow spindle or tube i. One extremity of the said rod k is attached to the
movable ring or collar j by means of a pin which passes through a slot
the hollow spindle or tube i. is a spiral spring, one extremity of which bears
against the ring or collar and the other against the movable ring or collar; so as to
maintain the latter in its normal position and to take up the back lash. The upper
or one extremity of the hollow spindle or tube i is plugged or formed solid and is
provided with a countersink in which engages a point bearing m provided in the
bracket B and the lower or other extremity of the rod k is formed conical or pointed
and is arranged to engage in a corresponding countersink at or near the other end of
the beam or balance lever u. n is a worm wheel firmly secured upon the hollow
spindle or tube i and gearing with a corresponding worm o provided upon the shaft
or arbor C of the electro-motor. is a worm also firmly secured upon the said hollow
spindle or tube i, and gearing with a corresponding worm wheel 7 firmly secured to
or formed on a spindle connected by suitable gearing with the counter or registering
mechanism F. is an adjustable contact piece with which the beam or balance lever a
is adapted to form or make contact as hereinafter described. s is an adjustable
weight or counterpoise for balancing or adjusting the beam or balance lever a. The
hollow spindle or tube i will be rotated by the electro-motor B through the said
worm o and worm wheel n.
A
The electro-motor B is driven as hereinbefore mentioned by a shunt or derivation
from the main current, or by a current from any suitable source. This current is
arranged to pass through the beam or balance lever a, and when no current passes in
the main coil c the contact between the said beam or balance lever a and contact
piece is broken and the said current is also broken or interrupted. The said beam
or balance lever, bears against or forms contact with the contact point or piece r when
oscillated by the varying strength of the current to be measured, thus making or
completing, and interrupting or breaking the circuit to the said electro-motor.
suitable fly wheel is sometimes employed for equalizing the motion of the said electro-
motor and for maintaining the rotary motion of the latter during the short intervals
or periods during which the circuit thereto is interrupted or broken. The beam or
balance lever a is so adjusted that when no current is passing in the circuit to be
measured it will be in a state of equilibrium and the electrical contact with the
contact point or piece r be only just broken, so that the slightest current passing in the
main coil e will attract the coil d thereto and through the rod e destroy the equilibrium
and press the said beam or balance lever a against the said contact point or piece r and
complete the circuit, when the electro-motor B will revolve.
The operation of the apparatus is as follows that is to say-The speed of the
electro-motor B is so regulated that at any moment the pull of the weighted arms g
of the centrifugal governor is equal to the pull of the current being measured. Any
increase of the said current will cause the coil d to approach the coil or magnet c in
the said circuit and thus through the spindle e lower or depress the extremity of the
said beam or balance lever a connected therewith and consequently raise or elevate
the other extremity thereof and complete or make the electrical circuit to the electro-
motor through the contact point or piece r. The speed of the said electro-motor will
then be increased and the arms g carrying the balls f of the governor will fly outwards
by centrifugal force overcoming the resistance of the spring and drawing down, or
using the ring or collar j to descend, or move so as to also shift or move the rod k,

page_text: and therefore depress the extremity of the beam or balance lever a connected there-
with. The electrical contact of the beam or balance lever a with the contact point or
piece is thus broken, and the said beam or balance lever resumes its normal position of
equilibrium. Consequently the current to the motor is interrupted and the speed thereof
decreases until the pull of the current overcomes the force of the said governor,
when the electrical contact of the beam or balance lever a with the contact point or
piece › is again made.
The number of revolutions of the electro-motor B is registered or recorded by the
counter or registering device F and from this is deduced the quantity of the electric
current that has passed through the circuit to be measured.
Figure 2 illustrates a modification wherein the hereinbefore described centrifugal
governor apparatus is dispensed with and I provide a spindle t upon which is firmly
secured the worm-wheel and the worm p. The upper extremity of the said spindle
is supported on a point bearing m in the bracket B and the lower extremity thereof
extends through a slot a' provided in the beam or balance lever a and is supported in
a conical or other suitable hearing m¹ in the bed plate or base plate A. 2 is a cup or
receptacle secured at or near one extremity of the beam or balance lever u. The said
cup or receptacle is provided with plates or baffles ¹ and with a central tube or
sleeve through which passes the said spindle t. vis another tube closed at the
upper extremity and firmly attached to the said spindle t in such a manner that it will
extend into the said cup or receptacle u and surround the tube or sleeve ². The
tube is provided externally with a worm or screw-thread . The cup or receptacle v
is filled with mercury glycerine or other suitable liquid, and should the spindle t
(which is driven by the electro-motor B in a similar manner to the herein before
mentioned hollow spindle or tube i) exceed a predetermined number of revolutions
the extremity of the beam or balance lever a supporting the mercury cup or
receptacle will be depressed by the action of the worm or screw thread l on the
mercury in the said cup or receptacle and the electric contact of the said beam or
balance lever a with the contact point or piece r be broken The circuit to the
electro-motor is thus momentarily interrupted as before.
The plates or baffles u prevent a rotary motion from being imparted to the mercury
or other liquid in the cup or receptacle u by the action of the worm or screw thread v1.
Instead of the said worm or screw thread helical blades are sometimes employed.
By altering or modifying the said coils and the counting or registering mechanism
the strength or intensity of the current to be measured may be recorded, instead of
the amount or quantity thereof.
My apparatus is also advantageously applicable for weighing or measuring
substances. In this case one extremity of the said beam or balance lever is
suitably connected to the platform tray, or receptacle upon, or in which the substance
to be weighed or measured is deposited and the speed of the said electro-motor is
arranged to indicate upon a suitable dial or dials the amount of the said weight, or
the measure or quantity of the said substance.
When the apparatus is employed for registering or recording the amount or
quantity, or the strength or intensity of alternating currents I prefer to drive the
electro-motor by a current derived from a separate source of supply.
It is obvious that I can employ clockwork or any other motor in place of the
electro-motor hereinbefore mentioned. In this case I employ any convenient device
such as a brake, escapement or the like for permitting the operation of the said motor
relatively to the amount or quantity of the current, or of the substance to be weighed
or measured.
Although have hereinbefore described convenient and advantageous means for
carrying my said invention into practice it is obvious that I can somewhat further
modify the construction of my improved apparatus for measuring the amount or
quantity of an electric current passing through a circuit, or the strength or intensity
of the said current, or for weighing or measuring substances, without departing in
any way from the nature of my said invention. For instance in place of the movable

page_text: coil I sometimes employ a suitable iron core or magnet. In some instances I place
the revolving part of the hereinbefore mentioned electro-motor upon the shaft or
spindle carrying the centrifugal or other governing device.
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 1
claim is :-
First. The improved method of measuring electric currents substantially as herein-
before described, wherein the speed of a small electro-motor is caused to vary in
accordance with the quantity or amount of the electric current to be measured and to
balance mechanically the strength, pull or intensity of the said current, and wherein
the number of revolutions of the said electro-motor is recorded upon a suitable
counter or registering apparatus, as, and for the purposes, above specified.
Second. An apparatus for measuring electric currents comprising an electro-motor
driven by the current in a shunt or derivation from the main circuit or by a current
from any suitable separate circuit, a coil placed in the main circuit or the circuit
through which flows the current to be measured, a coil placed in a shunt or derivation
from the main circuit or a soft iron core, a beam or balance lever or other suitable
means for making and breaking the said circuit to the electro-motor in accordance
with the quantity or amount of the electric current to be measured, or the strength or
intensity of the said current, and suitable means for registering or recording the
number of revolutions of the said electro-motor substantially as and for the purposes
hereinbefore specified.
Third. The improved apparatus for measuring electric currents comprising a motor,
a beam or balance lever, two or more coils, a centrifugal or other governing device,
and a suitable counter or registering device substantially as described.
Fourth. The modification of my improved apparatus for measuring electric currents
substantially as described with reference to Figure 2 of the accompanying drawing.
Fifth. The modification wherein my improved apparatus is adapted for weighing or
measuring substances substantially as described.
Sixth. The improved apparatus for measuring electric currents substantially as
described with reference to Figure 1 of the accompanying drawing, and operating as
and for the purposes herein before specified.
Latou
ALFRED LYSTER SHEPARD.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.