Improvements in Meters or Apparatus for Making Measurement of Electrical Energy.
Year: 1893

page_text: Date of Application, 4th Apr., 1893
Complete Specification Left, 2nd Aug., 1893-Accepted, 21st Oct., 1893
PROVISIONAL SPECIFICATION.
Improvements in Meters or Apparatus for Making Measurement of
Electrical Energy.
A communication from abroad by HERBERT CLARENCE WIRT, of 12, Millmont
Street, Boston, in the State of Massachusetts, one of the United States of
America, Electrician.
I, Alfred GEORGE BROOKES of 55 and 56 Chancery Lane, in the County of
London, Chartered Patent Agent do hereby declare the nature of this invention to
be as follows:-
My invention relates to improvements in meters or apparatus for making a
registered measurement of electrical energy.
Heretofore great difficulty has been experienced in producing a meter which
would measure alternating electrical currents with any degree of accuracy. Most
of the meters brought out for this purpose so far, are of the particular type known
as motor-meters, and consist, usually of a small electric motor which actuates a
counting train and which is provided with some kind of a load which is intended to
vary in such a way as to allow the speed of the motor to be proportional to the
energy to be measured.
These motor-meters have been found objectionable, first, on account of the fact
that the friction of the moving parts prevents the meter from starting up under
small currents, and renders the registration very inaccurate under light loads;
second, the large number of turns which it is necessary to use upon the series coils
which are placed directly in the circuit, causes a very great drop of potential
through the meter; and third, the motors and retarding devices usually follow
different laws and consequently do not balance each other, the result being very
inaccurate registrations throughout most of the range of the meter.
The object of my invention is to provide a motor meter for the measurement of
alternating electric currents, which shall be free from the above objections, and
which shall be simple, reliable, accurate, and inexpensive to construct.
In most of the motor-meters heretofore devised for the measurement of alterna-
ting electric currents, the motor has been of the particular type whose action is
dependent on the principle of a rotating magnetic field. Such meters as usually
constructed.do_not_develope a torque directly proportional to the energy passing
through them but more nearly proportional to the square-of-the-current,-and.fans,.
revolving either in air or in some liquid having usually been used for retarding
devices. The resisting moment of such retarding devices is not directly proportional
to the speed of rotation, but to soine higher power, and in most cases it does not
seem to follow any well defined law. As a consequence the retarding device does
not properly balance the power developed by the motor and inaccurate registration
of the meter is the result.
Now I have discovered that a motor constructed upon the principles and after
the manner hereinafter described will develope a torque directly proportional to the
energy passing through the motor.
By loading this meter with a retarding device whose resisting moment is directly
proportional to the speed of rotation, I get a speed of rotation of the motor shaft
which is directly proportional to the electrical energy I wish to measure, and the
addition of some mechanism for counting the number of revolutions of the motor
is all that is necessary to produce an electric meter which shall accurately register
the amount of energy passing through it.
One part of my invention therefore consists in an electric meter for the measure-
ment of alternating electric currents, the said meter containing an armature

page_text: consisting of a hollow closed conductor of copper or other non-magnetic conducting
material, of series coils through which passes the current to be measured, and shunt
coils arranged with their common axis at right angles to the common axis of the
series coils and connected as a shunt across the circuit leading to the translating
devices, said parts constituting an electric motor which developes a torque propor-
tional to the energy passing through the motor.
Also in an electric meter for the measurement of alternating electric currents,
the use with the service wires leading from the transformer or other electrical
source and carrying the current to be measured, of series coils placed in one of the
service wires, shunt coils arranged with their axis perpendicular to the axis of the
series coils and connected across the service wires in shunt to the lumps or other
translating devices, an inductive resistance placed in series with the shunt coils,
and an armature placed inside of said coils, said armature consisting of a hollow
closed conductor of copper or other conducting material.
Also in an electric meter for the measurement of alternating electric currents,
the employment of a shaft carrying an armature consisting of a hollow closed con-
ductor of copper or other non-magnetic conducting material, with a retarding device
consisting of a metallic conductor revolving between the poles of a permanent
magnet, and a conducting train for recording the number of revolutions of the
shaft.
Also in an electric meter for the measurement of alternating electric currents,
the use with a motor whose action is dependent upon the principle of a rotating
magnetic field and which developes a torque proportional to the energy passing
through it, of a retarding device developing a resisting moment proportional to the
speed of rotation, and a counting train for recording the number of revolutions of
the motor.
Also in an electric meter for the measurement of alternating electric currents,
the use with the service wires leading from the transformer or other electrical
source and carrying the current to be measured, of a motor whose action is dependent
upon the principle of a rotating magnetic field and which developes a torque
directly proportional to the energy passing through it, a retarding device consisting
of a metallic conductor revolving between the poles of a magnet, and a counting
train for registering the number of revolutions of the motor.
Also in an electric meter for the measurement of alternating electric currents,
the use with the service wires leading from the transformer or other electrical source
and carrying the current to be measured, of a motor consisting of a hollow closed
circuit armature revolving within a magnetic field produced by series coils carrying
the main current together with shunt coils placed at right angles to the series coils,
and a retarding device consisting of a metallic conductor revolving between the
poles of a magnet.
Also in an electric meter for the measurement of alternating electric currents,
the use with a shaft carrying a commutatorless armature consisting of a hollow
closed conductor, of series coils through which passes the current to be measured,
shunt coils arranged with their axis perpendicular to the axis of the series coils and
connected as a shunt across the service wires, an inductive resistance placed in series
with the shunt coils, and a retarding device consisting of a metallic conductor
mounted upon the shaft revolving between the poles of a magnet.
Also in an electric meter for the measurement of alternating electric currents,
the use with the service wires leading from the transformer or other electrical
source and carrying the current to be measured, of series coils placed in one of the
service wires, shunt coils arranged with their axis perpendicular to the axis of the
series coils and connected across the service wires in shunt to the lamps or other
translating devices, an inductive resistance placed in series with the shunt coils, a
shaft upon which is mounted an armature arranged to rotate inside of the series
and shunt coils, said armature consisting of a closed circuit conductor without any
commutator, and a counting train for recording the number of revolutions of the
said shaft.

page_text: Also in an electric meter for the measurement of alternating electric currents,
the combination with the service wires leading from the transformer or other
electrical source and carrying the current to be measured, of series coils placed in
one of the service wires, shunt coils arranged with their axis perpendicular to the
axis of the series coils and connected across the service wires in shunt to the lamps
or other translating devices, an inductive resistance placed in series with the shunt
coils, a shaft carrying an armature arranged to rotate inside of the series and shunt
coils, said armature consisting of a hollow closed conductor without a commutator,
a retarding device consisting of a metallic conductor mounted upon the said shaft
and revolving between the poles of a magnet, and a counting train for recording
the number of revolutions of the said shaft.
Also in an electric meter for the measurement of alternating electric currents,
the method of winding the series coils carrying the main current, consisting in the
use of a winding of ribbon made of copper or other good conducting material wound
upon a spool or other suitable support, the different layers of the ribbon being
separated by layers of insulating material placed between, substantially as and for
the purpose set forth.
Also in the method of constructing an inductive resistance consisting in winding
a coil of wire around a bundle of sheet iron strips, bending the strips around the
two sides of the coil and cutting their ends off so as to form butt joints, thus
obtaining a compact double closed magnetic circuit through the coil.
Also in an electric meter for the measurement of alternating electric currents,
the method of constructing the armature for said meter, consisting in stamping
from copper or other metal two cup shaped pieces, joining them together by
soldering or otherwise, and thus forming a hollow conducting cylinder with closed
ends.
Also in an electric meter for the measurement of alternating electric currents,
the method of constructing the armature for said meter, consisting in spinning from
metal two cup shaped pieces, joining their edges together by soldering or otherwise,
thus forming a hollow cylinder with closed ends, and laminating the side of said
cylinder by making longitudinal saw cuts through the metal of the sides.
Also in an electric meter for the measurement of alternating electric currents,
the method of constructing the armature of said meter, consisting in casting from
brass or other metal a cylindrical shaped piece forming a hollow closed conductor.
Also in an electric meter for the measurement of alternating electric currents,
the method of constructing the armature of said meter, consisting in winding upon
a suitable frame-work a number of coils of wire, the planes of said coils being
parallel to the axis of said armature, and the ends of said coils being joined upon
each other so as to form a separate closed conductor of each coil.
Dated the 4th day of April 1893.
COMPLETE SPECIFICATION.
Improvements in Meters or Apparatus for Making Measurement of
Electrical Energy.
A communication from abroad by HERBERT CLARENCE WIRT, of 12, Millmont
Street, Boston, in the State of Massachusetts, one of the United States of
America, Electrician.
I ALFRED GEORGE BROOKES of 55 & 56 Chancery Lane in the County of
London, Chartered Patent Agent 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 improvements in meters or apparatus for making a
registered measurement of electrical energy.

page_text: Heretofore great difficulty has been experienced in producing a meter which
would measure alternating electrical currents with any degree of accuracy. Most
of the meters brought out for this purpose so far, are of the particular type known
as motor-meters, and consist, usually of a small electric motor which actuates a
counting train and which is provided with some kind of a load which is intended to
vary in such a way as to allow the speed of the motor to be proportional to the
energy to be measured.
These motor-meters have been found objectionable, first, on account of the fact
that the friction of the moving parts prevents the meter from starting up under
small currents, and renders the registration very inaccurate under light loads;
second, the large number of turns which it is necessary to use upon the series
coils which are placed directly in the circuit, causes a very great drop of potential
through the meter; and third, the motors and retarding devices usually follow
different laws and consequently do not balance each other, the result being very
inaccurate registrations throughout most of the range of the meter.
The object of the invention is to provide a motor meter for the measurement of
alternating electric currents, which shall be free from the above objections, and
which shall be simple, reliable, accurate, and inexpensive to construct.
In most of the motor-meters heretofore devised for the measurement of alternating
electric currents, the motor has been of the particular type whose action is dependent
on the principle of a rotating magnetic field. Such meters, as usually constructed
do not develope a torque directly proportional to the energy passing through them
but more nearly proportional to the square of the current, and fans, revolving either
in air or in some liquid having usually been used for retarding devices. The
resisting moment of such retarding devices is not directly proportional to the
speed of rotation, but to some higher power, and in most cases it does not seem
to follow any well defined law. As a consequence, the retarding device does not
properly balance the power developed by the motor and inaccurate registration of
the meter is the result.
Now it has been discovered by my correspondent that a motor constructed upon
the principles and after the manner hereinafter described will develope a torque
directly proportional to the energy passing through the motor.
By loading this meter with a retarding device whose resisting moment is directly
proportional to the speed of rotation, I get a speed of rotation of the motor shaft
which is directly proportional to the electrical energy I wish to measure, and the
addition of some mechanism for counting the number of revolutions of the motor is
all that is necessary to produce an electric meter which shall accurately register the
amount of energy passing through it.
One part of the invention therefore consists in an electric meter for the measure-
ment of alternating electric currents, the said meter containing an armature
consisting of a hollow closed conductor of copper or other non-magnetic conducting
material, of series coils through which passes the current to be measured, and shunt
coils arranged with their common axis at right angles to the common axis of the
series coils and connected as a shunt across the circuit leading to the translating
devices, said parts constituting an electric motor which developes a torque
proportional to the energy passing through the motor.
Also in an electric meter for the measurement of alternating electric currents, the
use with the service wires leading from the transformer or other electrical source
and carrying the current to be measured, of series coils placed in one of the
service wires, shunt coils arranged with their axis perpendicular to the axis
of the series coils and connected across the service wires in shunt to the lumps
or other translating devices, an inductive resistance placed in series with the shunt
coils, and an armature placed inside of said coils, said armature consisting of a
hollow closed conductor of copper or other conducting material substantially as
will be described.
Also in an electric meter for the measurement of alternating electric currents, the
employment of a shaft carrying an armature consisting of a hollow closed conductor

page_text: of copper or other non-magnetic conducting material, with a retarding device
consisting of a metallic conductor revolving between the poles of a permanent
magnet, and a conducting train for recording the number of revolutions of the
shaft, substantially as will be described.
Also in an electric meter for the measurement of alternating electric currents, the
use with a motor whose action is dependent upon the principle of a rotating
magnetic field and which developes a torque proportional to the energy passing
through it, of a retarding device developing a resisting moment proportional to the
speed of rotation, and a counting train for recording the number of revolutions of
the motor, substantially as will be described.
Also in an electric meter for the measurement of alternating electric currents,
the use with the service wires leading from the transformer or other electrical
source and carrying the current to be measured, of a motor whose action is
dependent upon the principle of a rotating magnetic field and which developes a
torque directly proportional to the energy passing through it, a retarding device
consisting of a metallic conductor revolving between the poles of a magnet, and a
counting train for registering the number of revolutions of the motor, substantially
as will be described.
Also in an electric meter for the measurement of alternating electric currents,
the use with the service wires leading from the transformer or other electrical source
and carrying the current to be measured, of a motor consisting of a hollow closed
circuit armature revolving within a magnetic field produced by series coils carrying
the main current together with shunt coils placed at right angles to the series coils,
and a retarding device consisting of a metallic conductor revolving between the poles
of a magnet, substantially as will be described.
Also in an electric meter for the measurement of alternating electric currents,
the use with a shaft carrying a commutatorless armature consisting of a hollow
closed conductor, of series coils through which passes the current to be measured,
shunt coils arranged with their axis perpendicular to the axis of the series coils and
connected as a shunt across the service wires, an inductive resistance placed in series
with the shunt coils, and a retarding device consisting of a metallic conductor mounted
upon the shaft revolving between the poles of a magnet.
Also in an electric meter for the measurement of alternating electric currents,
the use with the service wires leading from the transformer or other electrical source
and carrying the current to be measured, of series coils placed in one of the service
wires, shunt coils arranged with their axis perpendicular to the axis of the series
coils and connected across the service wies in shunt to the lamps or other trans-
lating devices, an inductive resistance placed in series with the shunt coils, a shaft
upon which is mounted an armature arranged to rotate inside of the series and
shunt coils, said armature consisting of a closed circuit conductor without any
commutator,-and-a-counting-train-for-recording-the-number-of-revolutions-of-the-
said shaft.
Also in an electric meter for the measurement of alternating electric currents,
the combination with the service wires leading from the transformer or other
electrical source and carrying the current to be measured, of series coils placed
in one of the service wires, shunt coils arranged with their axis perpendicular to
the axis of the series coils and connected across the service wires in shunt to
the lamps or other translating devices, an inductive resistance placed in series
with the shunt coils, a shaft carrying an armature arranged to rotate inside of the
series and shunt coils, said armature consisting of a hollow closed conductor without
a commutator, a retarding device consisting of a metallic conductor mounted upon
the said shaft and revolving between the poles of a magnet, and a counting train for
recording the number of revolutions of the said shaft.
Also in an electric meter for the measurement of alternating electric currents,
the method of winding the series coils carrying the main current, consisting in the
use of a winding of ribbon made of copper or other good conducting material wound
upon a spool or other suitable support, the different layers of the ribbon being

page_text: separated by layers of insulating material placed between, substantially us and for
the purpose set forth.
Also in the method of constructing an inductive resistance, consisting in winding
a coil of wire around a bundle of sheet iron strips, bending the strips around the
two sides of the coil and cutting their ends off so as to form butt joints, thus
obtaining a compact double closed magnetic circuit through the coil, substantially
as will be described.
Also in an electric meter for the measurement of alternating electric currents,
the method of constructing the armature for said meter, consisting in stamping
from copper or other metal two cup shaped pieces, joining them together
by soldering or otherwise, and thus forming a hollow conducting cylinder with
closed ends.
Also in an electric meter for the measurement of alternating electric currents,
the method of constructing the armature for said meter, consisting in spinning
from metal two cup shaped pieces; joining their edges together by soldering
or otherwise, thus forming a hollow cylinder with closed ends, and laminating the
side of said cylinder by making longitudinal saw cuts through the metal of
the sides.
Also in an electric meter for the measurement of alternating electric currents,
the method of constructing the armature of said meter, consisting in casting from
brass or other metal a cylindrical shaped piece forming a hollow closed conductor.
Also in an electric meter for the measurement of alternating electric currents,
the method of constructing the armature of said meter, consisting in winding upon a
suitable framework a number of coils of wire, the planes of said coils being parallel
to the axis of said armature, and the ends of said coils being joined upon each other
so as to form a separate closed conductor of each coil.
In the accompanying drawings,
Fig. 1 is a front view of the meter, the right half being sectioned through the
centre of the shaft so as to show the internal construction;
Fig. 2 is a side view of the meter, partly sectioned as before
Fig. 3 is a plan view of the meter, the right half being sectioned through the
centre of the armature ;
Figs. 4 and 5 are section views shewing details of the construction of the inductive
resistance;
Fig. 6 is a diagram shewing one of the various methods of connecting the meter
in the circuit.
Referring to Figs. 1, 2, and 3, S and S' are the series coils which carry the
current to be measured.
These coils consist of a few turns of heavy wire or of a copper ribbon wound upon
spools U, U, made of wood, vulcanite or other insulating material.
The two coils are connected together in series and the other ends are connected,
one by means of the wire O' to the binding post M', and the other by means of the
wire Ŏ to the binding post M.
T and T are the shunt coils and are arranged with their axis perpendicular to
the axis of the series coils, so that there will be no induction between the series
coils and the shunt coils.
These shunt coils are wound with small wire upon the spools V, V', as shewn.
The spools U, U³, and V, VI, are secured to the standards C, C¹, by means of
screws a, a, etcetera, and c, c, etcetera, as shewn.
Standards C and C¹ are connected at the top by means of the T-shaped piece D,
which carries the the counting train K, and also the adjustable bearing R.
This bearing supports the upper end of the shaft E, the lower end turning in a
jewelled step bearing J, as shewn.
Shaft E, carries the armature A, mounted so as to revolve freely inside the field
coils U, U', and V, V¹.
The armature A, consists of a closed metallic circuit, made of such shape as to
embrace as many as possible of the magnetic lines produced by the field coils.

page_text: There are many different ways of constructing the armature, the essential point
being to secure a closed metallic circuit around the magnetic lines of the field, and
this regardless of the relative positions of the armature and the field coils. The
armature may be built up of some light non metallic core or frame-work wound
with one or more closed circuits of wire, or it may be made of a metallic casting
forming a closed circuit or a number of closed circuits, or, as I prefer, it may be a
hollow cylinder of copper or other good conducting material.
The cylindrical part may be continuous, or it may be laminated by longitudinal
saw cuts.
In general, the construction of the armature may be varied to meet various
conditions of practice, the essential point being, as before stated, to secure a closed
conductor, which in any position shall embrace as many as possible of the magnetic
lines of the field. The shaft E carries near its lower end, a disc G, of copper or
other conducting material, and this disc revolves between the poles of a permanent
steel magnet.
An inductive resistance Q is placed in series with the shunt coils.
This inductive resistance, cross sections of which are shewn in Figs. 4 and 5,
consists of a coil of wire Q, surrounded by a double closed magnetic circuit of
iron H which gives the coil a very high coefficient of self-induction.
The object of the coil is to retard the phase of the current in the shunt coils, and
also to reduce the shunt current to a minimum amount without the loss of energy
which a dead resistance would occasion.
The shaft E, carries at its upper end a worm which engages with the gearing
of the counting train K and causes it to record the number of the revolutions of
the shaft.
The whole apparatus as above described is mounted on a cast base B, B, which
affords suitable supports for all of the various parts.
In installing the meter, wires are run from the binding posts M and N to the
electrical source, which may be a dynamo electric machine or a transformer.
Wires from the other posts M' and N', run to the lamps or other translating
devices.
The binding posts N and N¹ are connected by a bar as shewn in Fig. 1.
The method of connecting the meter in the circuit is shown in Fig. 6, which
represents the meter as connected in the secondary circuit of a transformer to
measure the energy consumed by incandescent lamps. p represents the primary
coil of the transformer, and s, its secondary coil.
Wires from the secondary lead to the binding posts M and N, and M' to N' to
the lamps e, e, e, etretera.
S and S' are the series coils of the meter, T and T' the shunt coils, and Q the
inductive-resistance.
The shunt circuit is shown as connected across from near binding post M to the
bar between N and N¹.
The right hand end may be connected between the two coils S and S¹ or it may
be connected on the other side of the coils near the binding post M¹.
Qis shewn as connected between the shunt coils and the binding posts N
and N.
It may also be connected between the two coils T and T' or it may be connected
between those coils and the binding post M.
The effect upon the action of the meter of changing these connections as indicated,
is very slight, but the connections as shewn in the diagram seem to give the best
results in practice.
The action of the apparatus is as follows:-Two sets of armature currents are
induced in the closed circuit of the armature by the series coils and by the shunt
coils and each proportional to the inducing current.
The armature currents induced by the shunt coils act upon the series coils and
end to produce rotation of the armature, the torque being proportional to the
product of armature current by series current, or in other words to the watts

page_text: Deing consumed 10 све circuit beyond the meter auu WHICH
measure.
15
Again the armature currents induced by the series coils react upon the field
established by the shunt coils and the result is as before, a torque proportional to
the watts being consumed in the circuit beyond.
Hence the motor develops a power which is proportional to the energy
measured.
The metallic conductor or disc, on being revolved across a constant magnetic
field, has eddy currents set up in it which tend to oppose the motion of the disc,
and the result is a retarding or resisting effect upon the motion of the disc, which is
proportional to the speed of revolution.
Owing to this retarding effect of the disc and magnet, the speed of the motor is
kept exactly proportional to the energy which is passing through the meter, and
the counting train, which records the number of revolutions of the armature, thus
affords a measure of the energy which is being consumed by the lamps or other
translating devices.
I do not confine myself to the special form of apparatus shewn and described
above, but claim broadly the general arrangement of parts and principle of
operation as set forth and they may be embodied in any forms of construction such
as shall be found in practice to be best suited to the end in view.
The improvement involves a radical departure in the construction and principle
of operation of motor-meters, the invention consisting broadly, of an alternating
current electric motor, operating upon the principle of a rotating magnetic field,
and developing a torque directly proportional to the energy passing through it; a
retarding device which develops a resisting moment directly proportional to the
speed of rotation and forming a load for the motor; and mechanism for registering
the number of turns of the shaft of the motor.
I make no claim upon the special arrangement of coils above described, for
producing a rotating field, such an arrangement having long been in use in electric
motors for various purposes.
Nor do I lay claim to the method of retarding the movement of the motor by the
use of disc and magnet.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In an electric meter for the measurement of alternating electric currents, the
combination with an armature consisting of a hollow closed conductor of copper or
other non-magnetic conducting material, of series coils through which passes the
current to be measured, and shunt coils arranged with their common axis at right
angles to the common axis of the series coils and connected as a shunt across the
circuit leading to the translating devices, these combined parts constituting an
electric motor which develops a torque proportional to the energy passing through
the motor.
2. In an electric meter for the measurement of alternating electric currents, the
combination with the service wires leading from the transformer or other electrical
source and carrying the current to be measured, of series coils placed in one of the
service wires, shunt coils arranged with their axis perpendicular to the axis of the
series coils and connected across the service wires in shunt to the lamps or other
translating devices, an inductive resistance placed in series with the shunt coils, and
an armature placed inside of said coils, said armature consisting of a hollow
closed conductor of copper or other conducting material, substantially as shewn and
described.
3. In an electric meter for the measurement of alternating electric currents, the
combination with series coils for the current to be measured; shunt coils arranged
with their common axis at right angles to that of the series coils, and connected a
a shunt across the service wires of the translating device and a shaft carrying an

page_text: armature consisting of a hollow closed conductor of copper or other non-magnetic
conducting material, of a retarding device consisting of a metallic conductor
revolving across a constant magnetic field, and a counting train for recording the
number of revolutions of the shaft substantially as shewn and described.
4. In an electric meter for the measurement of alternating electric currents, the
combination with a motor consisting of a hollow closed circuit armature revolving
within a rotating magnetic field produced by series coils carrying the main current
together with shunt coils placed at right angles to the series coils, of a retarding
device consisting of a conductor revolving across a constant magnetic field, and a
counting train for recording the number of revolutions of the motor, substantially
as and for the purpose described.
5. In an electric meter for the measurement of alternating electric currents, the
combination with the service wires leading from the transformer or other electrical
source and carrying the current to be measured, of a motor consisting of series coils
and shunt coils placed at right angles to each other and surrounding a hollow
closed circuit armature, a retarding device consisting of a conductor revolving
across a constant magnetic field, and a counting train for registering the number of
revolutions of the motor, substantially as shewn and described.
6. In an electric meter for the measurement of alternating electric currents, the
combination with the service wires leading from the transformer or other
electrical source and carrying the current to be measured, of a motor consisting of a
hollow closed circuit armature revolving within a magnetic field produced by series
coils carrying the main current together with shunt coils placed at right angles to
the series coils, and a retarding device consisting of a metallic conductor revolving
across a constant magnetic field, substantially as shewn and described.
7. In an electric meter for the measurement of alternating electric currents, the
combination with a shaft carrying a commutatorless armature consisting of a
hollow closed conductor, of series coils through which passes the current to be
measured, shunt coils arranged with their axis perpendicular to the axis of the
series coils and connected as a shunt across the service wires, an inductive resistance
placed in series with the shunt coils, and a retarding device consisting of a metallic
conductor mounted upon the shaft and revolving across a constant magnetic field,
substantially as and for the purpose set forth.
8. In an electric meter for the measurement of alternating electric currents, the
combination with the service wires leading from the transformer or other electrical
source and carrying the current to be measured, of series coils placed in one of the
service wires, shunt coils arranged with their axis perpendicular to the axis of the
series coils, and connected across the service wires in shunt to the lamps or other
translating devices, an inductive resistance placed in series with the shunt coils, a
shaft upon which is mounted an armature arranged to rotate inside of the series
and shunt coils, said armature consisting of a closed circuit conductor without any
commutator and a counting train for counting the number of revolutions of the
said shaft, substantially as set forth-and-described.
9. In an electric meter for the measurement of alternating electric currents, the
combination with the service wires leading from the transformer or other electrical
source and carrying the current to be measured, of series coils placed in one of the
service wires, shunt coils arranged with their axis perpendicular to the axis of
the series coils and connected across the service wires in shunt to the lamps or
other translating devices, an inductive resistance placed in series with shunt coils,
a shaft carrying an armature arranged to rotate inside of the series and shunt coils,
said armature consisting of a hollow closed conductor without a commutator, a
retarding device consisting of a metallic conductor mounted upon the said shaft and
revolving across a constant magnetic field, and a counting train for recording the
number of revolutions of the said shaft, substantially as and for the purpose set
forth.
10. The herein before described combination or arrangement of parts of a meter

page_text: or apparatus for making a registered measurement of electrical energy as and for
the purposes set forth.
Dated the 1st day of August 1893.
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.