An Electricity Meter for Alternating Currents.
Year: 1889

page_text: Date of Application, 23rd Sept., 1889
Complete Specification Left, 2nd Nov., 1889-Accepted, 21st Dec., 1889
PROVISIONAL SPECIFICATION.
An Electricity Meter for Alternating Currents.
I, OTTO TITUS BLATHY, electrical engineer, subject of the King of Hungary
resident at Budapest, Hungary, II Hauptstrasse 75 do hereby declare the nature of
this invention to be as follows:
This invention relates to apparatus for measuring the electrical energy consumed in
a circuit of alternating currents in a given time, by recording the number of revolutions
of a rotating body in that time.
The rotating body may be in the form of a disc, solid or hollow cylinder, or other
solid of revolution, and may be made of one or of several metals. The simple form of
the meter is a dise fixed on an axis arranged so that the edge of the disc passes
through two magnetic fields, the one field situated at an interval of 90° from the
other.
One of the fields is that of an electromagnet having its coils in the main circuit so
as to take the whole of the current, or it may be in a shunt from the main circuit with
an interposed resistance so as to take a fraction of the current. The other field is also
that of an electromagnet. in shunt from the main circuit. The currents exciting the
two fields with a difference of phase act on the disc so as to make it revolve
continuously, and the number of revolutions are registered by a counter geared to the
axis of the disc.
Instead of two magnetic fields situated at right angles to each other, there may be
a greater number arranged around the disc. And, instead of discs, hollow cylinders
or bodies of such like form may be employed, in some cases with iron cores to
diminish the magnetic resistance when the body revolves within two sets of opposite
poles.
Within the disc or revolving boily enrrents are set up which may be modified in
direction by cutting out portions of the metal. The rotation may be retarded by a
fan flyer fixed on the axis, or by another disc on the axis arranged to revolve in fields
of permanent or electromagnets tending to retard its rotation. The currents exciting
the fields of the meter may be primary currents from the main circuit, or they may be
secondary currents from transformers having their primary currents drawn from the
main circuit.
Dated this 23rd day September 1889.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
An Electricity Meter for Alternating Currents.
I, OTTO TITUS BLATHY, Electrical Engineer, Subject of the King of Hungary,
resident at Budapest Hungary, II Hauptstrasse 75, 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 invention relates to apparatus for measuring the electrical energy consumed
in a circuit of alternating currents in a given time, by recording the number of
revolutions, of a rotating body made in that time. The rotating body may be in the
form of a disc, solid or hollow cylinder, or other, solid of revolution, and may be made
of one metal or of several metals. It is acted upon by two magnetic fields, or two groups
of fields, displaced in phase, from one another. This displacement of phase results
from the fact that the one field, or group of fields, is produced by the main current,

page_text: while the other field or group of fields, is excited by a coil of great self-induction
shunted from those points of the circuit, between which the energy consumed is to be
measured. The magnetic fields, however do not cross one another within the solid of
revolution, as in the well known arrangement of Ferrari but pass through different
parts of the same, independent of one another.
Figs. 1 and 2 of the accompanying drawings show a simple form of this electricity
meter with two magnetic fields. The rotating body which is acted upon by the two
fields H and N, displaced in phase from one another, is a metallic dise M. The coil of
the electro magnet His traversed by the main current, and that of the electro-
magnet N is shunted between the mains as indicated by Fig. 3, where A is any source
of alternate currents and L are lamps or any other consumers of electricity connected
parallel. The disc Mis caused to rotate in the direction determined by the connection
of the two electro magnets. If they are so connected; that assuming no displace-
ment of phase, they would have equal direction of lines of force, the disc moves from
the series magnet towards the shunt magnet. When the connection is opposed the
revolution takes place in the opposite direction. The number of revolutions is recorded
by suitable counting apparatus.
The phenomenon of revolution may be explained as follows: Both the electro-
magnets N and H produce induced currents within the disc M in consequence of the
fluctuations of the exciting currents. The paths of the mean current lines are shown
in Figs. 4 and 5 by the dotted curves F H and F N. If the inductive resistance of
the shunt coil N is very great as compared with its ohmic resistance, its pliase of
magnetisation is displaced for nearly one quarter of a phase from that of the series
magnet, as is indicated diagrammatically in Figs. 6 and 7, where Z H is the wave of
the series magnetisation and Z N that of the shunt, magnetisation. Fig. 6 shews the
magnets connected so as to have apparently the same polarity in this case, the phase
of the shunt magnet N lags behind that of the series magnet H; consequently, the
phase of the eddy (or Foucault) currents, induced by the former, represented by the
dotted wave FN, also lags behind that of the eddy currents FH; induced by the series
field, by nearly one quarter of a phase. When the eddy currents of one field are at
their maximum value, those of the other field pass through zero, and vice versu, The
maximum values of the eddy currents FH and F N very nearly coincide with the
maximer of the magnetisations FN and F H as may be seen from Fig. 6, and
the eddy currents FH are always attracted by the magnet N (Fig. 5 arrow 1) while
the eddy currents F N are always repelled by H (Fig. 4, arrow 1). The rotation,
therefore takes place continually from H towards N.
Fig. 7 shews the two electro inagnets connected so as to have apparently opposed
polarities, it also shews that the eddy currents F H are repelled by the magnet N,
while those F N are attracted by the magnet II, the disc, therefore in this case rotates
in the direction of the dotted arrow 2 in Figs. 4 and 5.
The rotation of the disc through the two magnetic fields produces within the body
of the disc eddy currents B H and B N the paths of which are indicated in Figs. 8
and 9. These eddy currents B Hand B N retard the dise M, as for their production
a certain amount of energy is required which is supplied by the attraction and
repulsion of the fields N and I and, eddy currents FH and F N respectively. In
consequence of this retarding the number of revolutions of the disc is such as to make
the work done and that expended equal to one another.
It has already been mentioned that two groups of magnetic fields may be employed
instead of two fields only Figs. 10 and 11 show as an instance, an arrangement with
two series fields Hand H and two shunt fields N and N
In order to get an
addition of the attractive and repulsive effects of the four fields H H N¹ and N2 upon
the eddy currents produced in the two halves of the disc indicated respectively by F N¹
and F N in Fig. 12 and by F E and F H in Fig. 13, the magnet coils belonging to
the same group must be connected so as to generate opposite directions of the lines of
force. If for example the lines of force of 11 pass downwards through the dise M
those of He must traverse the disce upwards. For this reason eléctro-magnets of the
forms shown in Figs. 14, 15 and '16 may be advantageously employed.

page_text: In Fig. 14 each pair of electro-magnets placed symmetrically with respect to the disc
serve to produce one group of the fields. In Fig. 15 and 16 one of these electro-magnets
has substituted for it a yoke S, S, without any coil. In Fig. 15 both the magnets are
upon one side of the disc and both the yokes upon the other side whilst in Fig. 16 an
electro magnet and a yoke are placed upon each side.
The external form of the magnetic fields may be altered in many different ways
without altering the nature and operation of this meter. As an illustration one form
of magnet with two limbs is shewn in Figs. 17 and 18. In all cases, however, the
fields H and N must be independent of one another and must not in any way interfere
with or intersect one another, they must not cross one another anywhere nor may they
have any common parts.
Instead of a disc any other rotating body or other form may be used such for instance
as a hollow cylinder. Figs. 19 & 20 shew a meter with two double.fields H¹ and He
and N and N, arranged in different planes and acting upon a hollow cylinder M.
The operation of this apparatus is similar to that above described. The impelling and
the retarding eddy currents circulate in the metal of the hollow cylinder in the
interior of which one or several subdivided iron cores are placed in order to diminish
the magnetic resistance of the fields H and N. The iron parts may advantageously be
stationary they inay however revolve with the cylinder.
In this construction the form and number of the magnetic fields may be altered as
formerly described. Fig. 21 shows a modification in which there are two pairs of
magnets, producing eight fields H, H, H, and H, and N1 N2 N# N.
In this electricity meter the number of revolutions of the rotating body is
proportional to the energy that is to be measured within a very considerable range.
It is found by experience that this range may be enlarged by using special brakes
or retarding magnets to act directly on the rotating body M or to act upon another
body moved by M. Such a brake magnet may be applied to a meter of any of the
forins and constructions, mentioned above, either as a single magnet or as a group of
magnets, distributed over the circumference of the rotating body.
Fig. 22 shews the disc of the meter, illustrated in Figs. 1 and 2 provided with a
permanent brake magnet B acting upon the disc M. this magnet having a form as
shewn in Fig. 23 similar to the cores of the electro inagnets H and N. The brake
magnet as shewn in Fig. 23a may be an electro magnet excited by electricity
from any source A such as a primary or secondary battery or by an alternating
current.
The external form of the maguet may be varied in many ways, but care must be
taken to choose a form in which the magnetic circuit is as nearly as possible closed
otherwise the field strength of the maguet when it is of the permanent kind might in
time be diminished.
The meter of the form shewn in Figs. 10 and 11 is in Figs. 24 and 25 shewn with
several brake magnets B, acting upon a separate revolving body D which
may be a disc as shewn or may be a ring, cylinder, ball, or have any other suitable
form.
This solid D as well as M may be made of one metal or of several metals. In
Fig. 26a a disc is shewn made of two metals and in Fig. 266 it is shewn made of three
metals. Fig. 27 shews a hollow cylinder made of two metals. The rotating body
may have holes or slots formed in it to direct the eddy currents in certain paths.
Fig. 28 shows a disc made with radial slots.
For the magnetic brake above described may be substituted, any other known
braking apparatus such as flyers or these may be used in addition to the magnetic
brake.
Instead of passing the total main current through the apparatus it may be shunted
in the well known manner from a fixed resistance passed by the main current, more-
over also either or both of the currents the main and the shunt may be first transformed
producing secondary currents to operate the meter.

page_text: Having now particularly described and ascertained the nature of this invention
and in what inanner the same is to be performed I declare that what I
claim is :-
An electricity meter för alternating currents consisting of a counter registering the
revolutions of a disc or other solid of revolution caused to rotate by the inductive and
dynamic action of two magnetic fields or groups of fields, independent from and not
intersecting nor interfering with one another, the one field being excited by a coil
supplied by the main current or a fraction thereof or by a secondary current induced
thereby and the other field being excited by a coil of great self induction supplied by
a current shunted from the main circuit or by a secondary current induced by the
shunted current, substantially as described.
Dated this 2nd day of November 1889
ABEL & IMRAY,
Agents for the Applicant.