Improvements in Electric Meters.
Year: 1898

page_text: Improvements in Electric Meters.
I, EMILE BATAULT, of 6, Rue de l'Université, Geneva, Switzerland, Doctor of
Medicine, do hereby declare the nature of this invention to be as follows:-
This meter is a most simple alternating current motor in which the whole
scale of registration is accurate and this as well on highly inductive as on non-
inductive circuits. The starting being possible with a very small current though
no running of the meter is to be feared when the main current is not passing
through it.
The necessary supply of energy is quite unimportant, no special brake is neces-
sary when the meter is used on a circuit at a constant E. M. F.; if not so a
permanent magnet may be added as brake, as will be seen.
My meter consists chiefly of a new combination of following parts: A shunt
wound electro-magnet inducing eddy currents in a metallic disc or other solid
of revolution rotating freely in the magnetic field of the electro-magnet; of a
conductor carrying the current to be metered and wound round a portion of the
iron of the poles of the shunt magnet, and of other new combinations of parts,
metallic rings, closed circuits and various details to obtain energy meters.
I, sometimes carry out my invention in the following manner: A U-shaped
shunt wound electro-magnet A A¹ A8 is placed with its branches A¹ A2 upwards
so that their extremities come in the same horizontal level; above the U, at a
small distance is provided a fixed horizontal armature B, armature and magnet
are made of thin iron plates.
A horizontal metallic disc D, preferably of aluminium, on a vertical shaft C,
is arranged to rotate horizontally between the electro-magnet and its armature,
that is to say in the magnetic field so produced. The diameter of the disc is
about the same as the external width of the pole pieces.
The magnetism of the shunt magnet induces eddy currents in the disc at both
extremities of a same diameter at the same time, and if this disc is caused to
rotate by any given impulsion. these eddy currents oppose themselves to its motion,
the checking action varying directly as the speed.
The current to be measured passes by way of a conductor winding round_a
portion only of the iron branches A1 A2 of the shunt magnet as shewn in EE',
(a few windings only are necessary as a rule so that EE could scarcely be called
coils, but it will be clearer to use that denomination for the description).
For this purpose the upper part of the branches A¹ As leaves in its inside a
free space parallel to the diameter of the disc, which free space can be in the
middle of the core or unsymmetrical to the axis of the core (see Sheet 2 Fig. 5
to 16). This free space may be deeper than necessary to put in the coil and be
filled underneath the coil by a non-magnetic material. It can also have the shape
of Fig. 14 with a non-magnetic part I and the iron laminae shorter in the middle
part than on the outsides, or as in Fig. 15 the external parts need not be in
the same level what is practical for standardising purposes.
When the current to be measured is used on a non-inductive circuit, the phases

page_text: of the series and shunt currents approach to a difference of 90° and the cores of
the shunt magnet are magnetized at same intervals, totally by the shunt current
and partially by the main current.
:
We obtain in this way two fields produced in the same iron but inducing in
the disc Foucault currents differing in phase, the consequence of which is a torque
which drives the disc; this torque being quite proportional to the current flowing
in the main coils, when the E. M. F. is constant. The speed of the disc is there-
fore proportional to the current
to be measured.
If the shunt magnet is not vitalized and if we pass a current in the series wind-
ings disposed as in EE Fig. 1 and 2 the dise shows no tendency to move even
at heavy loads.
'
The armature B is pivoted in its center F so that it can be moved round Fin
a horizontal plane and take positions like B' B2 or B3 B4 Fig. 2. These changes
in the position of B allow to regulate the starting speed of the meter, as they
can give to the disc a tendency to be moved in any chosen direction or stop any
actual motion produced by the fact of putting the main coils on the shunt magnet
iron.
The motion that can be imparted to the disc by the fact of bringing the main
coils on the shunt magnet iron varies with the different kinds of windings. This
motion is great, for instance, with the windings of Fig. 5, 9, 10 and 11 and very
small if any with those of Fig. 7 and 8.
This motion may be stopped not only by a given position of the armature B
but also by other means, such as the bringing of a metallic ring of suitable size
on the free iron part of the shunt magnet on a or d, for instance, Fig. 5 or on
both a and d or by approaching near or d a metallic piece especially an iron
one.
The tendency to movement may be exaggerated with an aluminium disc and
inipart to it a very slow motion in certain positions, the disc stopping always again
nearly in the same positions. I have found that a still greater security for the
stopping of the aluminium disc, may be obtained by drilling a hole through it
at some place near its periphery and by plugging it with a small metallic disc or
pin, of copper or silver for instance, which needs not be thicker than the disc itself
as shown in H Fig. 1 and 2.
The effect of this pin H is easy to be seen whilst the disc D has a very slow
movement; when H comes near the shunt magnet iron the speed of I) increases
and H passes between the magnet and the armature B, but as soon as H has to
leave the iron core it is retained and the motion is stopped. This checking is
stronger with a larger pin H.
In this way I can safely counterbalance the retarding effects of friction for small
currents by giving the necessary tendency to movement and still be quite sure
that no running of the meter will happen with no load.
It is very important that a meter should be a good wattmeter, that means
accurate whether with inductive or non-inductive circuits.
My meter as just described shows an error of defect of registration when used
on highly inductive circuits. The phase-differences in this case becoming very
small, smaller indeed than they ought to be, or even none at all, because the phase-
differences between the shunt current and non-inductive series current are
never 90°, in which case there would be no error, as they can only approach 90°.
I have found a most simple way of completely correcting this error in meters
where the driving force depends on the shunt and main currents being in different
phases as this one, or as my former one described in Patent No. 25729 of 1896
for instance.
I put round the whole magnetic core of the shunt magnet a metallic ring, of
preference a copper one, as shown in L, or when the main winding is on the two
poles of the shunt magnet I preferably put one ring on each pole as in LL', and
the apparatus becomes a perfect wattmeter if the section of the metallic ring
is rightly chosen.

page_text: When the section is too small the meter shows still a defect of registration on
highly inductive circuits, though less than without it; if the section is too large
the error of registration is one of excess on the same inductive current; with the
right section we have a perfect energy meter registering equally well the watts
on inductive or non-inductive circuits. The ring may be replaced by a suitably
proportioned short circuited winding or closed coil.
If it is not absolute necessary that the ring should be close to the disc, it may
be somewhere round the shunt magnet iron, neither does it need to be close to the
iron, it may be larger. The currents produced in the ring induce in the disc,
directly and through the iron, or through the iron only according to the position
of the ring, eddy currents which have a difference of phase of much more than 90°
with the series current when non-inductive, so that the action of the field of the
ring and of the field of the series current on the disc, produce a driving effect
which is greater with inductive currents than with non-inductive and the action
of the shunt current and of the main current on the contrary, as said before, has
more motive force with non-inductive than with inductive currents.
A convenient combination of these two actions gives the true energy meter and
is obtained by the position and section of the ring.
The ring or closed coil may be employed with all kind of different main wind-
ings shewn and described before.
Such as yet described the meter is a very good energy meter, on the condition
of being used on a circuit at a constant E. M. F. which is generally the case in
practice. Then, supposing a central station has a normal E. M. F. of 120 volts,
it may be that it is sometimes 123 but also at other times it may become 117,
the registration of the meter would be a little too small with 123 volts but a
little too large with 117 and practically the error would be of no account. The
conditions would be the same as with ampere-meters on constant current.
Some central stations however prefer true wattmeters and I can obtain this
result by controlling the rotation of the disc driven as said before, by a
permanent magnet P, of which the poles are disposed close to the two surfaces
of the disc, and acting as a brake, but it is then absolutely necessary that this magnet
should be constant, if not, the indications of the meter will vary according to the
variations in the brake-force, here is the objection to the use of permanent
magnets. It is almost impossible to secure completely constancy in a permanent
magnet, but what we need is not absolutely constancy in the magnet itself but
indeed in its braking action.
To obtain this I have devised the following arrangement Fig. 17. The poles p P³
of the magnet P are above and below the disc D so that the lines of force pass
through the disc and I provide on the outside of the disc an iron armature R,
carried by a spring S, at a convenient distance from p and so that R is attracted
by pp, which means that a certain number of lines of force are passing or rather
derived through it.
If I were removed, R would take the position R¹. Two small pins prevent R
from coming accidentally into contact with ppl then normally R should always
be at a certain distance from the poles of P. If the force of the magnet varies,
getting smaller for instance, which will nearly almost be the case, the armature R
under the influence of the spring S will come further from pp, the magnetic
derivation will be less and the number of lines of force passing through the disc
will remain the same as before. If the magnet gets stronger, R. will come
nearer and the brake-action remain constant, which is desired.
For the three wires distribution I use separately the coils E E¹ on each branch
of the U-shunt magnet as shown in Fig. 16 for instance.
For biphased meters I employ two shunt magnets M, N, placed at two opposite
extremities of a same diameter of the disc, as shown in Fig. 3 and 4. The pole
pieces of each shunt-magnet, in this case, are so disposed above and below the
disc at its periphery that Foucault currents are induced in it. The series
coils T and V are placed on a portion of the pole pieces as before, and are separate

page_text: for each shunt which is excited by a different phase. Three magnets may be
used for triphased currents.
The regulation of the starting speed of the disc is then obtained by displacing
the electro magnets as shown in dotted lines (M¹) the cores being no more in a
line with the disc's diameter.
031
1000
I, EMILE BATAULT, of 6, Rue de l'Université, Geneva, Switzerland, Doctor of
Medicine, 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:-
This meter is a most simple alternating current motor, in which the whole
scale of registration is accurate, and this as well on highly inductive as on non-
inductive circuits.
The starting of the meter is possible with a very small current, though no
running of the meter is to be feared when the main current is not passing through
it.
The necessary supply of energy is quite unimportant, no special brake is neces-
sary when the meter is used on a circuit at à constant E. M. F.; if not so a
permanent magnet may be added as brake, as will be seen.
My meter consists chiefly of a new combination of following parts, 1. A shunt
wound electro-magnet inducing eddy currents in a metallic disc, or other revolubly
mounted conducting body, located and rotating freely in the magnetic field of the
electro-magnet. 2). A conductor carrying the current to be metered and wound
through the core, about a portion only of the cross section of the pole pieces of
the shunt magnet. 3). Other new combinations of parts, metallic rings, closed
circuits surrounding the pole pieces, and various details to obtain energy meters.
I will now proceed to describe my invention in relation to the drawings filed
with my Provisional Specification, showing one of the manners of carrying it out,
reference being had to the letters and figures marked thereon.
Fig. 1 is a front elevation and Fig. 2 is a plan both showing the essential parts
of the apparatus.
Fig. 3 is a front elevation and Fig. 4 is a plan both showing the essential parts
of a different form of the meter.
Fig. 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 illustrate various modes of windings,
various shapes of the pole pieces and different details.
Fig. 16 shows the schematic connections of a three wires distribution.
Fig. 17 is a special view of the construction of the improved permanent brake
magnet.
Fig. 18 and Fig. 19 (drawings filed with my Complete Specification) illustrate
a construction more special for biphase and triphase meters.
Fig. 20 represents a diagram showing the connections for a biphase current
with three wires distribution.
Fig. 21 is diagram like Fig. 20 but for biphase currents with four wires.
Fig. 22 and 23 are diagrams showing the connections for triphase currents.
The same letters of reference indicate the same parts in all figures.
A U-shaped shunt wound electro-magnet AA'A² (Fig. 1 of the drawings filed
with my Provisional Specification) is placed with its branches A¹A² upwards,

page_text: so that their extremities come in the same horizontal level; above the U, at a
small distance is provided a fixed horizontal armature B. The magnet is made
of thin iron plates or wires. A horizontal metallic disc D), preferably of aluminium,
on a vertical shaft C, is arranged to rotate horizontally between the electro-magnet
and its armature, that is to say in the magnetic field so produced. The diameter
of the disc is about the same as the external width of the pole pieces.
The current to be measured passes through the core by way of a conductor
winding round a portion only of the iron branches AA of the shunt magnet, as
shewn in EE' (a few windings only are necessary as a rule and EE are short
series coils or solenoids.)
For this purpose the upper part of the branches A1 A2 leaves in its inside a
free space or slot, parallel to the diameter of the disc, which free space can be
in the middle of the core or unsymmetrical to the axis of the core, (see, Sheet 2,
Fig. 5 to 15). This slot may be deeper than necessary to put in the coil and be
filled underneath the coil by a non magnetic material I (Fig. 12 to 15). It can
also have the shape of Fig. 14, with a non magnetic part I and the iron laminae
shorter in the middle part than on the outsides, or as in Fig. 15 the external parts
need not be in the same level, what is practical for standardising purposes.
When the current to be measured is used on a non-inductive circuit, the phases
induced by the series coils which have nearly no self-induction and the phases
induced by the shunt coils which have a great self-induction approach to a differ-
ence of ninety degrees.
The core of the shunt magnet is thus magnetized at the same intervals, totally
by the shunt current and partially by the main current. The magnetic forces thus
produced in the same iron, induce in the disc D, Foucault currents, differing in
phase, the consequence of which is a torque which drives the disc; this torque is
quite proportional to the current flowing in the main coils, when the electro-motive
force is constant. The speed of the disc is therefore proportional to the current to
be measured.
The action is as follows: If we consider the shunt magnet alone, the series
coils being taken away and if we vitalize the shunt, eddy currents are set up in
the disc at both extremities of a same diameter at the same time and no move-
ment can be produced by such Foucault currents, but if the disc is caused to
rotate by any given impulsion, these eddy currents oppose themselves to its
motion; the checking action varying directly as the speed. If we were to put
series coils surrounding completely the pole pieces and vitalize them, abstraction
being made of the shunt coils, we would have a magnet working on the disc
exactly in the same conditions as the shunt magnet alone, only at a different
phase, and no motion could be produced. Even, if we now combine these two
actions, no rotation can take place, whatever may be the difference of the phases,
because the two fields produced exactly cover each other. For this reason, until
now, all meters with rotating fields were made with shunt magnets and series
magnets or coils placed aside the poles of the shunt magnet.
I have found that by winding the series coils through the core by splitting the
pole pieces, as described, a rotating field may be obtained in a most simple way,
because the series coil field does not cover completely the shunt field, it is a great
simplification in the construction, the rotating action is a very good one for our
purpose because the two fields are as close each other as they may possibly be,
very few turns are necessary for the series coils and the brake action of the
shunt remains complete. We have the action of two magnets in one core, which
is possible because the two magnetizations take place at different times.
This is SO true, that the series coils may be wound
produce like poles, the shunt winding being such as to produce always
different poles. There is an advantage, as will be seen, to wind the series coils
as shown in Fig. 1, because they can both be put on both front parts or on both
back parts of the slotted core and still their rotating actions on the disc add
themselves.
SO that they

page_text: If the series coils are wound to produce different poles one must be put on
the front iron part on one side and on the back iron part on the other (see Fig. 9,
10 and 11 for instance). As explained before, a disc located in the magnetic
field of a shunt magnet has no tendency to be moved and the slots in the pole
pieces introduce no difference as to this fact. But, when we bring the series coils
into the slots, eddy currents are set up in them by the shunt magnet, and these
eddy currents induce themselves in the disc Foucault currents of a different
phase of those produced directly by the shunt magnet and the disc begins to rotate,
although no work current passes through the coils.
Of course, such motion cannot be admitted and must be completely avoided.
The rotation that can be imparted to the disc, by the fact of bringing the main
coils on the shunt magnet iron, varies a great deal with the different kinds of
windings. This motion is great for instance, with the windings of Fig. 5, 9,
10 and 11 and very small if any with those of Fig. 1, 7 and 8.
It is easy to understand that, in the winding of Fig. 1 or 7 which produces like
poles when the main current passes through it, the eddy currents induced by
the shunt magnet, which has unlike poles, in the series coils are such that, in
one coil they have a tendency to move the disc in one direction and in the other
coil a tendency to move the disc in the opposite direction, because both series
coils are on the same side of the disc's diameter; but, with the main current
producing like poles in both series coils the driving actions add themselves. So
that with this winding, the tendency of the disc to rotate by the mere presence
of the series coils on the magnet is only the difference between the two, actions
of the coils taken separately, which difference is always very small if any.
With
the windings 9 and 10 these actions add themselves hence the greater movement
of the disc.
Another advantage of the winding of the series coils to produce like poles is,
that a short circuit has no bad influence on the meters in which a permanent
magnet brake is used.
The armature B is pivoted in its center F so that it can be moved round Fin
a horizontal plane and take positions like 131 132 or 133 134 Fig. 2. These changes
in the position of B allow to regulate the starting speed of the meter, as they
can give to the disc a tendency to be moved in any chosen direction or stop any
actual motion produced by the fact of putting the main coils on the shunt magnet
iron.
The tendency of the disc to rotate while no current is passing through the work
circuit may also be neutralized by surrounding, with a metallic ring or a closed
circuit, the portion a (Fig. 5) of the limb of the magnet core opposite to the portion
on which the series coils are fixed.
In this case the eddy currents induced in the ring or closed circuit, which passes
through the core, by the shunt coils, have a contrary action to the eddy currents
induced in the series coil by the same shunt coils, so that, with a suitable size
of the ring or a suitable resistance of the closed circuit, the motion may be
stopped, even in the case of windings like 5, 9 and 10. Such a closed circuit
may be used of course on both branches of the magnet, when the series coils are
on both poles.
Therefore, the tendency to movement may be regulated by the position of the
armature B and by the closed circuits or rings just described. This tendency
may be exaggerated with an aluminium disc and impart to it a very slow motion
in certain positions, the disc stopping always again nearly in the same positions.
I have found that a still greater security for the stopping of the aluminium
disc may be obtained by drilling a hole through it, at some place near its peri-
phery, and by plugging it with a small metallic disc or pin, of copper or silver
for instance, which needs not be thicker than the disc itself, as shown in H
Fig. 1 and 2.
The effect of this pin H is easy to be seen whilst the disc D has a very slow

page_text: movement; when H comes near the shunt magnet iron the speed of D) increases
and H passes between the magnet and the armature B, but as soon as H has to
leave the iron core it is retained and the motion is stopped.
This checking stronger with a larger pin H.
In this way I can safely counter-balance the retarding effects of friction for
small currents by giving the necessary tendency to movement and still be quite
sure that no running of the meter will happen with no load.
It is very important that a meter should be a good wattmeter, that means
accurate whether with inductive or non-inductive circuits.
The meter as just described shows an error of defect of registration when used
on highly inductive circuits the phase differences in this case becoming smaller
than they ought to be, because the phase differences due to the self-induction
between the shunt current and non-inductive series current, even in the best
conditions are never ninety degrees, in which case there would be no error: they
can only approach ninety degrees. I have found a most simple way of completely
correcting this error in meters where the driving force depends on the shunt and
main currents being in different phases.
By putting round the poles of the shunt magnet a metallic ring L and L' of suit-
able size. the apparatus becomes a perfect wattmeter. The proper section of the
ring is determined by experiment and by the following consideration:
When the section is too small the meter shows still a defect of registration on
highly inductive circuits, though less than without it; if the section is too large
the error of registration is one of excess on the same inductive current; with
the right section we have a perfect energy meter registering equally well the watts
on inductive or non-inductive circuits. The ring may be replaced by a suitably
proportioned short circuited winding or closed coil.
There need not be two rings. One ring on one of the poles may be sufficient.
It is not absolutely necessary that the ring should be close to the disc, it may.
be somewhere round the shunt magnet iron, neither does it need to be close to
the iron, it may be larger. The currents produced in the ring induce in the
disc directly and through the iron, or through the iron only according to the
position of the ring, eddy currents which have a difference of phase of much
more than ninety degrees with the series current when non-inductive. So that
the combined action of the field of the ring and of the field of the series current
on the disc produce a driving effect, which is greater with inductive currents than
with non-inductive and the action of the shunt current and of the main current
on the contrary, as said before, has more motive force with non-inductive than
with inductive currents. Indeed, non-inductive currents in the series coils, having
a phase difference of much more than 90 degrees with the field of the ring, would
have a tendency to move the disc in the opposite direction, which means that such
rings introduce a checking action for the non-inductive currents, on the contrary,
very inductive circuits having a phase difference of about 90° have a greater
driving action. A convenient combination of these two actions gives the true
energy meter and is obtained by the position and section of the ring.
The ring or closed coil may be employed with all kinds of different main wind-
ings shewn and described before.
Such as vet described the meter is a very good energy meter, on the condition
of being used on a circuit at a constant E. M. F., which is generally the case in
practice. Then, supposing a central station has a normal E. M. F. of 120 volts,
it may be that it is sometimes 123 but also at other times it may become 117,
the registration of the meter would be a little too small with 123 volts but a little
The con-
too large with 117 and practically the error would be of no account.
ditions would be the same as with ampere-meters on constant current.
Some central stations however, prefer true watt meters and I can obtain this
result by controlling the rotation of the disc, driven as said before, by a permanent
magnet P the poles of which are disposed close to the two surfaces of the disc

page_text: and act as a brake, but it is then absolutely necessary that this magnet should be
constant; if not, the indications of the meter will vary according to the varia-
tions in the brake-force, here is the objection to the use of permanent magnets.
It is almost impossible to secure completely constancy in a permanent magnet,
but what we need is not absolutely constancy in the magnet itself but indeed in
its brake-action.
To obtain this, I have devised the following arrangement, Fig. 17. The
poles of the magnet P are above and below the disc D, so that the lines of
force pass through the disc, and I provide on the outside of the disc an iron
armature R, carried by a spring S, at a convenient distance from p and 7 so
that R is attracted by pp¹, which means that a certain number of lines of force
are passing or rather derived through it.
If P were removed, R would take the position R'. Two small pins prevent R
from coming accidentally into contact with pp, then, normally R should always
be at a certain distance from the poles of P. If the force of the magnet varies,
getting smaller for instance, which will nearly always be the case, the armature R
under the influence of the spring $ will come further from p2, the magnetic
derivation will be less and the number of lines of force passing through the disc
will remain the same as before. If the magnet gets stronger R will come nearer p¹
and the brake-action remain constant which is desired.
For the three wires distribution I use separately the coils EE¹ on each branch
of the U shunt magnet as shown in Fig. 16 for instance.
For biphase meters I employ two shunt magnets M N, placed at two opposite
extremities of a same diameter of the disc, as shown in Fig. 18 and 19.
The pole
pieces of each shunt magnet, in this case, are so disposed above and below the
disc, at its periphery, that Foucault, currents are induced in it.
The series coils E and E are placed on a portion of the pole pieces, as before
passing through the core, and are separate for each shunt which is excited by a
different phase.
The line conductors carrying the current of each phase are connected to the
series coils as shown in the diagrams of Fig. 20 and Fig. 21. The series coils
of one phase may be wound on the two branches of each pole of one of the shunt
magnets, the winding passing always through the core. The series windings
may be put both below and above the disc.
The drawing hereto annexed shows one case of main winding, but the different
kinds described may be used.
This construction is good also for single phase, both shunt magnets being
connected in tension.
In this case one shunt magnet is sufficient, even for a three wires distribution,
on the condition of having two well insulated series coils on the magnet and
through its core. One of the windings may be below and the other above the
disc.
Rings or closed circuits disposals about the poles of the magnets, whether above
or below the disc, may be employed in all cases to obtain meters equally accurate
on inductive or on non-inductive circuits.
The regulation of the starting speed of the disc is obtained by displacing the
electro-magnets laterally as shown in dotted lines in M¹, the core being no more
in a line with the disc's diameter.
As it is well known that triphase currents may be measured by two watt-
meters, the construction shown in Fig. 18 and 19 representing really two watt-
meters acting on one moving body, may be used also for such currents.
The connections with the three conductors Z Z1 Z2 are shown in the diagrams
of Fig. 22 and Fig. 23. E and E are a schematic representation of the two
series coils; M and N are a schematic representation of the shunt coils and x, x², x³,
the three points of the triangle or star distribution.
A larger number of magnets may be used for others multiphase distributions.

page_text: Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what
I claim is;-
1. In an electric meter for alternating currents the combination, with a revolubly
mounted conducting body, of a magnet or magnets or equivalent devices, having
shunt coils and adapted to cause said conducting body to rotate under the influence
of the rotating field produced by passing an alternating current through the said
shunt coils and series coils conveniently disposed, and of rings or closed conduct-
ing circuits disposed about the poles of said magnet or magnets; substantially
as described and for the purpose set forth.
2. In an electric meter the combination with a revolubly mounted conducting
body of a magnet or magnets having shunt and series coils thereon, the series
coils being wound through the core, about a portion only of the cross section of
the core, and forming therewith an electro-magnetic device producing a rotating
field under the influence of the alternating currents passing through the shunt
and series coils, and of rings or closed conducting circuits disposed about the poles
or cores of said magnet or magnets; as described and set forth.
3. In an electric meter the combination with a revolubly mounted conducting
body, of cores having shunt and series coils thereon, the series coils being wound
through the core, about a portion only of the cross section of the core, and forming
therewith an electro-magnetic device producing a rotating field under the influence
of the alternating currents passing through the shunt and series coils; of rings
or closed conducting circuits disposed about the cores, and of a permanent magnet
having its poles near the moving body so as to act as a brake; substantially as
described and shewn.
4. In an electric meter the combination of a shunt electro-magnet provided at
a distance with a movable armature or of several displaceable shunt electro-
magnets, with a revolubly mounted conducting body located and rotating freely
in the magnetic field produced by the said electro-magnet or magnets, and with
one or several solenoids carrying the current to be measured and wound through
the core, about a portion only of the cross section of the poles of the shunt magnet
or magnets substantially as described and for the purpose set forth.
5. In an electric meter the combination of a shunt electro-magnet provided
at a distance with a movable armature or of several displaceable shunt electro-
magnets, the cores of the electro-magnets being surrounded with a metallic ring
or a closed conducting circuit of suitable resistance, with a revolubly mounted
conducting body, (controlled or not by a pemanent magnet acting as a brake)
located and rotating freely in the magnetic field produced by the said electro-
magnet or magnets, and with one or several solenoids carrying the current to be
measured and wound through the core, about a portion only of the cross section of
the poles of the shunt magnet or magnets, substantially as described and for the
purpose set forth.
6. In an electric meter the combination with a core and series and shunt coils
thereon and forming therewith an electro-magnetic device, the series coils being
wound about a portion only of the cross section of the core, of a conducting closed
circuit wound through the core, about another portion only of the cross section of
the core, and of a revolubly mounted conducting body located in the magnetic
field and caused to rotate by reason of the influence of the eddy currents induced
in it; substantially as described and for the purpose set forth.
7. In an electric meter the combination with a core, and series and shunt coils
thereon and forming therewith a laterally displaceable device, the series coils
being wound through the core about a portion only of the cross section of the
core, of a revolubly mounted conducting body located in the magnetic field and
caused to rotate by reason of the influence of the eddy currents induced in it,
substantially as described and for the purpose set forth.
8. In an electric meter the combination, with a revolubly mounted metallic

page_text: body freely rotating in a magnetic field, of a conducting piece or pin of a different
metai, plugged in or fixed on the moving body and so located that, by the move-
ment of the revolubly mounted body, said conducting piece accesses and recedes
from the magnetic poles, thereby checking false movement of the moving body,
substantially as described.
9. In an electric meter the combination, with a permanent magnet acting as a
brake on a moving body, of a movable magnetic armature carried on a spring,
and so arranged as path diverter that, by the variations in the magnetism of the
permanent magnet, the said armature comes nearer or further from its poles, in
order to act as a self regulator of the magnetic lines passing through the moving
body substantially as described and shown.
10. An electric meter as described consisting of a shunt electro-magnet A A¹ A²,
with the rings LL' about its poles and with its armature B movable round its
center F, of a rotating disc D with its metallic pin H and of series coils EE'
wound through the core, about a portion only of the cross section of the shunt
magnet core; as shewn and for the purpose set forth.
11. In electric meters the different kinds of series windings described and shewn
in the different figures.
D1100+1
Cantamh 1808