IMPROVEMENTS IN APPARATUS FOR MEASURING AND REGISTERING ELECTRIC CURRENTS
Year: 1882

page_text: LETTERS PATENT to Camille Alphonse Faure of 446 Strand in the County
of Middlesex for an Invention of "IMPROVEMENTS IN APPARATUS FOR
MEASURING AND REGISTERING ELECTRIC CURRENTS."
PROVISIONAL SPECIFICATION left by the said Camille Alphonse Faure at
the Office of the Commissioners of Patents on the 15th February 1882.
CAMILLE ALPHONSE FAURE of 446 Strand in the County of Middlesex
"IMPROVEMENTS IN APPARATUS FOR MEASURING AND REGISTERING ELECTRIC
CURRENTS"
One of the principal objects of this Invention is an instrument for permanently
registering the amount of electricity that is passing in a conductor so as to permit
the easy reading off of this quantity after different periods of time as a gas ineter
is read.
In such an instrument it is requisite that the speed of working should be directly
proportionate to the quantity of current passing and that the record should be
permanent and accurate.
The principle upon which my instrument is based is well known viz―that a
conductor conveying a current tends to rotate around a magnet.
In carrying the Invention into practice I employ a cylindrical electro-magnet
mounted vertically within a vessel containing mercury so that the electro-magnet
is surrounded with mercury a conductor in form like the flier of a spinning
machine is pivotted on the top of the magnet core and its arms dip down into the
mercury.
The same current, viz-the current to be measured is caused to circulate into
the coils of the magnet and into the moving conductor so that the moving force is
proportional to the square of the current. The resisting medium is the mercury in
the cup which for this purpose is made sufficiently deep. Now as the force
required to move any object through a liquid is proportional to the square of the
speed it follows the number of rotations of the conductor will be proportional to
ID 11

page_text: the current to be measured. The mercury cup is made to envelope the whole of
the top part of the magnet and is hermetically sealed up so that the inercury may
not escape during the carriage of the instrument and may not oxidise by contact
with the atinosphere.
The magnet is isolated from the mercury and the whole is so arranged that
tracing the current from one terminal of the instrument it may after traversing
the coils of the electro-magnet enter the mercury cup and then pass up both
branches of the rotating conductor and into the magnet core by the pivot and thus
rejoin the base upon which is the other terminal. The base affords lodgment for
the coils making the central rod or core into an electro magnet.
The top of the magnetic rod where the pivot rests is cupped and receives mercury
to ensure good electric contact. The quantity of mercury enclosed in the apparatus
is such that after turning the apparatus in any direction or upside down the pivot
mercury cup will always retain mercury when the apparatus is returned to its
normal position.
The registering part of the instrument may be independent of the above system
and generally it consists of an electro magnet and armature similar to that of an
electric bell and arranged with a train of wheels.
Each pulsation of the armature registers permanently. The circuit of this last
electro magnet is completed by means of a contact finger protruding into the first
instrument and receiving a current at a certain point in every revolution of the
rotating conductor.
This current may be derived from the current being measured or may be set up
by a separate battery.
The whole of the registering train of wheels or discs may be within the envelope
around the rotating conductor and may then receive direct motion and be seen
through a glass cover or it may be outside and receive motion by a spindle.
I use sometimes a permanent magnet instead of an electro-magnet but in this
case the square roots of the dial readings are to be taken as the true readings.
This applies also in the case when the electro magnet is circulated by a foreign but
constant current of known magnitude. These means are resorted to when the
currents to be registered are very weak and it is advisable to have a strong
magnetism as a base for the moving force.
Increased resistance to the motion of the rotating conductor may be applied by
alloying the mercury or more properly by resisting vanes which may be operated
from the outside of the envelope of mercury. In this manner the instruments
may be made use of with very varying strength of currents.
An instrument for indicating temporarily the strength of a current is based on
the above arrangements but instead of allowing the rotating conductor to revolve
continuously it is resisted by a spiral or other spring and the amount of deviation
of the conductor from a fiducial mark gives directly the value of the deflecting
current

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Camille Alphonse Faure in the Great Seal Patent Office on the
12th August 1882.
CAMILLE ALPHONSE FAURE of 446 Strand in the County of Middlesex.
"IMPROVEMENTS IN APPARATUS FOR MEASURING AND REGISTERING ELECTRIC
CURRENTS."
One of the principal objects of this Invention is an instrument for permanently
registering the amount of electricity that is passing in a conductor so as to permit
the easy reading off of this quantity after different periods of time as a gas metor
is read.
In such an instrument it is requisite that the speed of working should be directly
proportionate to the quantity of current passing and that the record should be
permanent and accurate.
The principle upon which my instrument is based is well known viz-that a
conductor conveying a current tends to rotate around a magnet.
In carrying the Invention into practice I employ a cylindrical electro magnet
mounted vertically within a vessel containing mercury so that the electro inagnet
is surrounded with mercury. A conductor in form like the flier of a spinning
machine is pivotted on the top of the magnet core and its arms dip down into the
mercury. The same current viz-the current to be measured is caused to circulate
into the coils of the magnet and into the moving conductor so that the moving
force is proportional to the square of the current. The resisting medium is the
mercury in the cup which for this purpose is made sufficiently deep. Now as the
force required to move any object through a liquid is proportional to the square of
the speed it follows the number of rotations of the conductor will be proportional
to the current to be measured. The mercury cup is made to envelope the whole of
the top part of the magnet and is hermetically scaled up so that the mercury may
not escape during the carriage of the instrument and may not oxidise by contact
with the atmosphere.
The magnet is isolated from the mercury and the whole is so arranged that
tracing the current from one terminal of the instrument it may after traversing
the coils of the electro-magnet enter the mercury cup and then pass up both
branches of the rotating conductor and into the magnet core by the pivot and thus
rejoin the base upon which is the other terminal. The base affords lodgment for
the coils making the central rod or core into an electro magnet.
The top of the magnetic rod where the pivot rests is cupped and receives mercury
to ensure good electric contact. The quantity of mercury enclosed in the apparatus
is such that after turning the apparatus in any direction or upside down the pivot
mercury cup will always retain mercury when the apparatus is returned to its
normal position.
The registering part of the instrument may be independent of the above system
and generally it consists of an electro magnet and armature similar to that of an
electric bell and arranged with a train of wheels.
Each pulsation of the armature registers permanently. The circuit of this last
electro magnet is completed by means of a contact finger protruding into the first
instrument and receiving a current at a certain point in every revolution of the
rotating conductor.
This current may be derived froin the current being measured or may be set up'
by a separate battery.
The whole of the registering train of wheels or discs may be within the envelope

page_text: around the rotating conductor and may then receive direct motion and be seen
through a glass cover or it may be outside and receive motion by a spindle.
I use sometimes a permanent magnet instead of an electro magnet but in this
case the square roots of the dial readings are to be taken as the true readings.
This applies also in the case when the electro magnet is circulated by a foreign but
constant current of known magnitude. These means are resorted to when the
currents to be registered are very weak and it is advisable to have a strong magnetism
as a base for the moving force.
Increased resistance to the motion of the rotating conductor may be applied by
alloying the mercury or more properly by resisting vanes which may be operated
from the outside of the envelope of inercury. In this manner the instruments may
be made use of with very varying strength of currents.
An instrument for indicating temporarily the strength of a current is based on
the above arrangements but instead of allowing the rotating conductor to revolve
continuously it is resisted by a spiral or other spring and the amount of deviation
of the conductor from a fiducial mark gives directly the value of the deflecting
current.
In order that my said Invention may be most fully understood and readily carried
into effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figures and 2 represent apparatus for measuring and registering electric
currents according to my Invention. Figure 1 shows in vertical section the
measuring portion of the apparatus; Figure 2 indicates the registering part. In
Figure 1, A is a cylindrical vessel of wood or ebonite or other material which is
nonconducting, and impermiable; it is closed by a cover B, the cover should fit air
tight so that the mercury which the vessel contains may be protected from contact
with the atmosphere. This vessel is divided into two compartments.
The iron
core C, is rendered magnetic by the passage of the electric current in the coils of
an insulated copper wire wrapped around its base at D. The upper part of the
core is covered to isolate it from the mercury by which it is surrounded. The
vessel A, and the core C, are fixed upon an iron plate E, which is mounted upon a
wooden base F. Another piece of iron G, completes the foot but this is not in
metallic contact with the piece E, it is separated from it by ebonite.
The upper part of the core C, is hollowed out to receive an axis or pivot H,
carrying the conductor I. The conductor is formed of platinum or iron wire, bent
to a U form and inverted; it, with its axis is moveable around the core C.
The hollow in the upper part of the core receives mercury and the quantity of
mercury in the vessel A, is such that when the instrument is laid upon its side
mercury enters the cavity and ensures its being properly charged.
The action of the apparatus is as follows:-
The current which has to be measured enters at + into the coils of the electro-
magnet, and traversing these in the direction of the arrow, it enters the mercury
by the contact M. It ascends by the two branches of the moveable conductor,
enters the central core by the pivot H and leaves it by the piece E.
The conductor I, then rotates with a velocity proportional to the number of 4
coul combs of current passing in a second of time. Upon the pivot H, there is a
platinum contact piece which at each revolution touches upon the light spring N.
This spring is also of platinum and is connected with the binding screw P so that
the electro magnet shewn at Figure 2 (of which the coils are connected at one end
with the piece G, and at the other end with P) is caused to attract its armature &
once to each rotation of the pivot. The armature, by means of a spring pawl
operates upon a ratchet wheel, the first of a registering train. The electro magnet
of the recorder may be operated by a separate battery or source of electricity, in
this case one terminal of the battery or other source should be connected at E, and
the other to the coils of the registering magnet.
6

page_text: The registering apparatus may be dispensed with, the vessel A being in this case
provided with a glass cover and the observation being made by counting the
number of rotations of the conductor in a given number of seconds.
m, is the
Figure 3 is a vertical section of another form of my measuring apparatus. a is
an insulating base of wood or other material, b is a central column which I prefer
to be of soft iron. c is a hollow iron cylinder upon which an insulated wire is
wound thus forming an electro magnet. d, is mercury contained in an annular space
between b and c. e is a nonconducting envelope of caoutchouc or other material
serving to isolate the piece b from the piece c. f, is a cover, g is a caoutchouc
washer. is a glass plate, another ring of caoutchouc beneath the edges of the
glass ensures a tight joint. In the middle of the glass h, there is a step i, to
receive a pivot j. The step is supported by a thin cross piece of wood. The lower
end of the pivot j, is received into a lower step k, which can be raised and lowered
a little by the screw ; the washers A, and ", being of india rubber.
rotating conductor, its branches dip into the mercury. The quantity of mercury
is such that when the instrument is laid down mercury enters the cavity in which
the pivot i, is contained, and when the instrument is again erected the surplus
mercury runs out by the overflow aperture at o. Thus mercury is maintained at
uniform height in the cavity. The pivot j, is cut away at j¹. n is a piece of
metal, isolated from b, and its end is in close proximity to the side of the pivot j,
except when the part j¹, comes round. The piece n is connected with a conducting
wire which transmits currents from it to the registering magnet seen in Figure 2.
The end of the piece n, being so close to the pivot j and touching the mercury in
the cavity, the mercury is drawn up between the piece n, and the pivot by capillary
attraction and as the pivot revolves establishes the intermittent contact required to
operate the registering apparatus.
The current enters the mercury at p, and from thence passes by the conductor m,
to the pivot j. It thus reaches the colum b and the screw plug 4, and it is led
away by the conductor q.
Having thus described the nature of my said Invention and the manner of
performing the same I would have it understood that I claim.
First. Apparatus for measuring and registering an electric current in which a
conductor carrying the current rotates about a magnet and controls another circuit
in which is included an electro magnet, or like instrument, propelling a mechanical
counter, substantially as described.
Second. Apparatus for measuring electric currents in which the current to be
measured is caused to pass through the coils of an electro magnet and through a
conductor which then revolves under the influence of the current and of the said
magnet overcoming the resistance of a fluid, substantially as described.
Third. Apparatus for measuring electric currents, substantially as described and
illustrated by the annexed Drawings.
In witness whereof I the said Camille Alphonse Faure have hereunto set my
hand and seal this Third day of August in the year of our Lord One
thousand eight hundred and sights