An Improved Electric Meter for Alternating and Continuous Currents.
Year: 1897

page_text: Date of Application, 4th Sept., 1897
Complete Specification Left, 4th June, 1898-Accepted, 16th July, 1898
PROVIDIUNAL DICITICATION.
An Improved Electric Meter for Alternating and Continuous
Currents.
I, PROSPER RENE BLONDLOT, Professor at the Faculty of Sciences, No. 8, Quai
Claude le Lorrain, Nancy, in the Republic of France, do hereby declare the nature
of this invention to be as follows:-
This invention relates to the general application to the measurement of elec-
tricity of a novel principle hereinafter described.
The device comprises a large bobbin with a horizontal axis. Within this
bobbin is suspended a second bobbin consisting of a ring formed of several turns of
wire. The circuits of the two bobbins, arranged in series, are traversed by the
current which it is desired to measure.
The ring within the large bobbin is movable around its vertical axis; with
this object it is supported by a lever resting upon a point, the current being con-
ducted to it by means of two cups containing mercury.
Under the influence of the current, the said ring sets itself in such a position or
at such an angle that its turns are parallel to those of the large bobbin, it then
remains at rest at this angle. If it is slightly displaced from this angle of
equilibrium, it executes isochronous oscillations. The period (T) of the oscillation
is in inverse ratio to the square root of the moment to which the ring is submitted
for a displacement equal to the angular unity; it is consequently inversely pro-
portional to the intensity () of the current. Thus the product Ti is constant. As
this product is the same thing as the quantity of electricity which has traversed
the section of the circuit during the time occupied by an oscillation, it follows
that: whilst an oscillation is taking place, a constant quantity of electricity passes
through the section of the circuit, whatever the intensity i and the period T
may be.
As a consequence of this, it is only necessary, in order to ascertain the quantity
of electricity supplied during any lapse of time, to maintain the oscillations during
such time and to count them.
I effect this in the following manner:
I cause the ring to oscillate to one side only of its position of equilibrium.
With this object a horizontal metallic arm is fixed to the ring; when the ring
has been displaced from its angle of equilibrium, the electro-dynamic action causes
it to resume its position of equilibrium, but, at the moment when it reaches the
same, the arm strikes against a spring or blade which the armature of an electro
magnet maintains applied to a fixed stop during the whole time that such electro
magnet is not acting.
At the moment of contact between the arm and the spring the circuit of this
electro magnet is closed; the spring is then liberated and imparts to the arm an
almost instantaneous impulse which causes it to complete a unilateral semi-
oscillation, and so on in continuation. Neither the amplitude of the oscillation
nor the extent of the impulse has any sensible influence upon the period.
027

page_text: A pawl fixed to the armature of the electro-magnet causes the first wheel of a
revolution counter to advance to the extent of one tooth for each oscillation of
the ring. In this manner, the oscillatory movement of the said ring is in nowise
affected by the passive resistances of the counter, since it is the electro-magnet
which causes this latter to move.
It is essential that, when the counter is not acting, the ring should be kept
displaced from its position of equilibrium as otherwise it might happen, with
extremely weak currents, that it would not start. The following arrangement
ensures its starting: A small bar of soft iron, provided at its middle point with a
lever resting on a point, is arranged along the axis of the bobbin (it passes through
the ring). A weak spring holds the bar out of the horizontal plane when no
current is traversing the apparatus. In its turn, the bar keeps the ring displaced
by means of a hanging portion fixed thereto which acts upon the arm.
When a current is passing the bar is instantaneously caused to lie along the
axis of the bobbin, and the ring, thus liberated, commences to oscillate, as already
stated. A fixed piece of soft iron against which the bar bears when the current
is passing, prevents any movement of the latter.
I may also wind around the bar a fine wire traversed by a current in shunt; in
this manner a straight electro magnet is obtained, upon which the bobbin exerts
a very considerable force, the apparatus is less delicate and the bar may be placed
outside the bobbin.
An Improved Electric Meter for Alternating and Continuous
Currents.
I, PROSPER RENE BLONDLOT, of 75, Rue Claude Bernard, Paris, Professor, and
late of No. 8, Quai Claude le Lorrain, Nancy, in the Republic of France, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following state-
ment:-
This invention refers to meters for recording the quantity of electricity passing
a given spot, and consists of a device embodying the practical application of a
new principle, namely,
That when a fixed bobbin acts upon a free bobbin in conditions hereinafter set
forth, these bobbins being traversed by the same current, the quantity of electricity
which traverses the section of the circuit, during one oscillation of the free bobbin,
is constant, whatever may be the intensity of the current and the duration of the
oscillation.
I will now describe my invention with reference to the accompanying drawings
in which:-
Fig. 1 shows the bobbin AA¹ with the ring or smaller bobbin B B¹ suspended
inside.
Fig. 2 shows a method of making and breaking the contact.
Fig. 3 shows enlarged details of Fig. 5.
Fig. 4 shows a sectional elevation of the meter with the mercury contacts.
Fig. 5 shows a plan view of the meter.
Fig. 6 shows a diagram of the general arrangement of the wires.

page_text: Referring to the figures annexed as examples of arbitrary shapes and sizes, A, A¹
is a large bobbin or reel with a horizontal axis.
Inside this bobbin is suspended a second bobbin or ring B, B¹ consisting of a
few rounds of metal wire (either copper, aluminium or other suitable metal or
alloy). The circuits of the two bobbins, are arranged as a series and are traversed
by the current to be totalised.
The sketch in Fig. 6 is solely designed to show the communications and not to
show the respective positions of the bobbins to one another as hereinafter explained.
The ring B B is free to move round an axle same being vertical, and to this
effect said ring carries a point resting on a bearing o and the current is led to
it by the intermediary of two mercury contacts gg.
The rods which are immersed in the mercury are of a metal not corrosible
therem, namely nickel, platinum, suitable alloys, plated metals, aluminium and
the like.
A layer of insulating liquid as for instance glycerine protects the mercury from
contact with the air. The inferior cup g may have a cover with free opening,
working on the lower rod in the case of abnormal lateral displacements of the
interior bobbin B'B'. Through the action of the current, the ring B'B' turns
itself in such a way that its helices are parallel to those of the bobbins AA and
it then remains in equilibrium in this azimuth. If it is slightly disturbed from
this azimuth of equilibrium it executes isochronous oscillations.
The period of each oscillation is in inverse ratio to the square root of the
momentum to which the ring is subjected for a divergence equal to the unit of
angle. The aforesaid period is therefore in inverse proportion to the intensity
of the current. It follows that the product of the period of oscillation and the
intensity of the current is constant. This product not being other than the
quantity of electricity which has traversed the section of the circuit during one
oscillation it results therefrom that during the time taken to effect one oscillation,
a constant quantity of electricity passes through the section of the circuit, whatever
may be the intensity or the period.
After this, to ascertain the quantity of electricity during an arbitrary lapse of
time it is only necessary to permit oscillations during the time and to count them.
This is how I attain this result.
I cause the ring B¹ B¹ to oscillate on one side only of its position when in
equilibrium.
For this purpose a horizontal metallic arm c shewn in Figs. 2 and 5, is fixed on
to the ring B, B, when said ring has been disturbed from its azimuth of
equilibrium, the electro-dynamic action brings it back again but the moment it
arrives back to its azimuth, the arm e comes and strikes against a spring R which
is held by the armature 1) of an electro-magnet E, E, against a fixed obstacle E',
all the time that the electro-magnet does not act.
At the moment of the contact of the arm c and the spring R, the circuit of this
electro-magnet is shut, the spring is then set free and gives an almost instantaneous
inpulsion to the arm which makes same accomplish a unilateral semi-oscillation
and so on.
Neither the length of the oscillation nor the strength of the momentum have
any measurable effect on the period. A catch arrangement fixed on to the
armature of the electro-magnet turns one tooth of the first wheel of a mechanical
counter c, o at each oscillation of B'B', as shewn in Fig. 5.
In this way the oscillatory movement of B' B¹ is in no way changed by the
passive resistances of the counter, as it is the electro magnet which makes this
last named move.
The current which feeds the electro magnet EE may be taken from the main
(distribution) current or led from an auxiliary source a battery or an accumulator.
The power required is very slight.
It is necessary when the meter is not in use that the ring B¹B¹ should be held

page_text: away from its state of equilibrium; as otherwise it might happen that it would
no longer be influenced by very weak currents.
The following arrangement ensure its correct position (Figs. 3 and 5) that is
to say: The motor couple of the meter is maximum when the free and fixed wires
of the bobbins are at right angles. It is on the contrary very weak when the
wires are almost parallel. This happens when the contact points C and R are
near one another. The frame bears at its upper part a light lever L, which has
at its extremity a small cylinder of soft iron F. A small magnetized bar B is
fixed to the frame.
When the two contact points i come near one another, the bar of soft iron comes
near the magnetized bar through the movement of the frame round its axis X; the
magnet operating in the same direction as the current which passes through the
apparatus. The two points of contact are in this way brought towards one
another and repulsed, afterwards by the effect of the electro magnet, as already
described, to a more advantageous position.
This disposition allows the machine to be made much more sensitive and of
its registering the very weakest supply of current.
In a general way the attraction of the magnet is destined to overcome the friction
during the return to the position of equilibrium, when the divergence from same
has become very small. The action of this magnet, not only ensures the good working
of the apparatus, but moreover increases its accuracy, as shown by observation
and in other ways.
The apparatus is fitted with all appliances necessary to regulate its working.
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. The general adaptation to the electric meter of the principle herein recited
namely "That when a fixed bobbin acts upon a free bobbin in the conditions set
forth, these bobbins being traversed by the same current, the quantity of electricity
which traverses the section of the circuit during one oscillation of the free bobbin,
is constant whatever may be the intensity of the current and the duration of the
oscillation, as herein described and set forth.
2. The special application of this principle to the construction of the said electric
meters, as herein described and set forth.
3. The arrangement herein explained, ensuring the action of the apparatus,
even for very weak currents, as herein described and set forth.
4. The entire or partial combination of the devices and details herein described
as employed in the practical construction of electric meters, as herein described
and set forth.
Dated this 4th day of June 1898.
S. S. BROMHEAD,
Patent Agent, 171, Queen Victoria Street, London, E.C.