Improvements in Apparatus for Measuring a Supply of Electricity.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Measuring a Supply of Electricity.
WILLIAM ARTHUR Price, Teign House, Westcombe Park Road, London, S.E.,
Electrician, do hereby declare the nature of this invention to be as follows:-
My invention relates to the construction of instruments which measure the
quantity of electricity supplied from any source, such as a public distribution
system, during any given time. I desire for the purpose of such an instrument
so to regulate the rotation of an electrical motor deriving power from any con-
venient source that its speed shall be at all times proportional to the current
which the instrument is intended to measure, which I call the house current. To
do this I fix on the axis of the motor a disc of copper, or other conducting
material, revolving in its own plane with the motor. Near this disc is mounted
on pivots a magnet or magnetic system free to move through a small are between
limiting stops, and so placed that the rotation of the disc tends to move it up
to one stop by the mutual action of the disc and the magnet. A conductor
carrying the house current is placed near the magnet in such a position that it
tends to move the magnet up to the other stop in the opposite direction to that
in which the disc moves it, by the mutual action between the current and the
magnet. When the magnet is drawn against one stop by the action of the disc
the electrical circuit of the motor is broken, and when it is drawn against the
other stop by the action of the house current the circuit of the motor is com-
pleted. Thus when the action of the house current is more powerful than that
of the disc the circuit of the motor is completed and its speed accelerated; when
less powerful the circuit of the motor is interrupted and its speed reduced. In
practice the speed of the motor will be constantly changing within narrow limits,
alternately rising above and falling below a speed at which the actions on the
magnet of the disc and the house current are equal. When this is the case the
mean speed of the motor is proportional to the house current, and a counter
attached to the motor measures the supply of current.
To prevent any action on the magnet of wind produced by the rotating disc I
place a shield or screen between the disc and the magnet.
Dated this 22nd day of November 1898.
Improvements in Apparatus for Measuring a Supply of Electricity.
I. WILLIAM ARTHUR PRICE, of Teign House, Westcombe Park Road, London,
S.E., Electrician, do hereby declare the nature of this invention and in what
[Price 8d.]

page_text: manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
-
My invention relates to the construction of apparatus for measuring the quantity
of electricity supplied in a direct current from any source, such as a public
distribution system, during any given time. I desire for the purpose of such
apparatus so to regulate the rotation of an electrical motor deriving power from
any convenient source that its speed shall be at all times proportional to the
current which the apparatus is intended to measure and which I call the house
current. To do this I fix on the axis of the motor a mass of copper, or other
electrically conducting material having some convenient figure of revolution
about the axis of the motor revolving in its own plane with the motor. The figure
of revolution may conveniently be a disc, and I shall speak of it hereinafter as
disc. Near this disc is mounted on an axis a magnet or magnetic system free
to move through a small are between contacts or limiting stops, and so placed
that the disc when rotating tends to move it up to one stop or contact by the
mutual action of the moving disc and the magnet. A conductor carrying the
house current is placed near the magnet in such a position that it tends to move
the magnet up to the other stop or contact in the opposite direction to that in
which the disc moves it, by the mutual action between the current and the
magnet. When the magnet is drawn against one stop or contact by the action
of the dise the supply of electrical energy to the motor is partly or wholly inter-
rupted, and when it is drawn against the other stop or contact by the action of
the house current the supply of energy to the motor is continued. Thus when
the action of the house current is more powerful than that of the dise the supply
of energy to the motor is continuous and its speed accelerated; when less powerful
the supply of energy to the motor is interrupted and its speed reduced. In
practice the speed of the motor will be constantly changing within narrow limits.
alternately rising above and falling below a speed at which the actions on the
magnet of the disc and the house current are equal. When this is the case the
mean speed of the motor is proportional to the house current, and a counter
attached to the motor measures the supply of current.
To prevent any action on the magnet of wind produced by the rotating disc a
shield or screen may be placed between the disc and the magnet.
This apparatus may be used also to measure the output of an electric lighting
station, the charge or discharge of an accumulator battery or for any other similar
purpose. In describing the apparatus I shall for convenience treat it as applied
to the measurement of a direct current house supply.
For these purposes of my invention I take an electrical motor of any convenient
form, which revolves about an axis, and is supplied with current from any con-
venient source of power, and by suitable means I cause this motor to revolve
always at a speed proportional to the rate at which electricity is passing into
the house, so that the total number of revolutions made by the motor in any
given period is proportional to the total quantity of electricity which has passed
in that period. For the purpose of counting the number of revolutions made I
attach an ordinary counting mechanism to the motor axle. The motor may be
of any suitable construction, and the source of electric energy for driving the
motor may be a battery or public distribution mains and the current may be
direct or alternating.
Now my invention principally relates to the mode of regulating the rotation
of the motor, so that its speed shall always be proportional to the current flowing
into the house from the supply mains.
One form of my apparatus is shown diagrammatically in Figures 1 and 2.
In these figures A indicates the armature of a direct current motor receiving
current from a source of electric energy E (shewn here by way of example as a
battery) through brushes b12, and revolving in the field of a permanent magnet M.
The revolutions of the motor armature are counted by a counter B. On the axis

page_text: of the motor armature A and revolving with it is fixed a disc C made of any
suitable electrically conducting material but preferably aluminium or copper.
Close to the disc and parallel to it is placed conductor dd, through which
passes the current which it is desired to measure. A permanent magnet P of
contracted horse-shoe shape pivotted freely on an axle è e is so placed that the
disc C, and a suitable portion of the conductor dare situated in the space
between the north and south poles (which are marked N and S respectively) of
the magnet P in the relative positions shown in the figures. The said portion
of the conductor dis preferably flattened out in order that the gap between
the magnet poles may be made as narrow as possible. With this arrangement
of the parts when the disc C is revolving in the direction of the curved arrow in
Figure 2 between the poles of the magnet the electro magnetic action between
the moving disc C, and the magnet P will tend to turn the magnet P about its
axle e e in the direction from a to z. When the current to be measured is passing
in the conductor from d to the north and south poles N and S of the magnets
being in the positions shown the electro magnetic action between the current in
and the magnet P will tend to turn the magnet P in the opposite direction,
viz.: from z to .
Attached to the magnet P is a contact piece g working between two fixed
contacts h and k so placed that the movement of the disc C tends to press the
contact piece against the contact h, while the action of the current in the
conductor tends to press the contact piece against the other contact .
The contact piece g is connected by means of a flexible connection, marked 7.
to one brush or terminal 12 of the motor, and the contact k is connected to one
pole or terminal of the source of electric energy E. The other terminal of the
source of electric energy is connected to the other brush or terminal 6 of the
motor, and it may be convenient to insert in this connection a suitable resistance
R3. Then, when the contact piece is pressed against the contact the current
from the battery E passes through the armature A of the motor and tends to
accelerate ifs rotation. When the contact piece g leaves the contact k the circuit
through the motor armature A is interrupted, and the armature A and disc C
tend to stop. If necessary a condenser K of suitable capacity and a suitable
resistance R¹ may be connected in the way shewn in Figure 2 between the brushes
of the motor, in order to prevent any sparking at the contacts gk. When the
speed of the disc C is such that the magnet P is drawn by it from a to z more
powerfully than it is drawn by the current in the conductor dd from ≈ to r.
the contact piece g will leave the contact k, and the speed of the motor and disc C
will tend to decrease. When the speed of the disc C is such that the action of
the current in the conductor on the magnet P is the more powerful, the
magnet P will be drawn from z to r, the contact piece g will be pressed against
the contact k, and the rotation of the motor and disc will be accelerated.
By this action the speed of the disc is constantly varying sometimes being
a little above, sometimes a little below, a mean speed which would exactly
balance the current in the conductor as regards their respective actions
on the pivoted magnet P.
It is well known that the mutual forces of a moving conductor and a magnet
are within certain limits of speed nearly proportional to the speed of the con-
ductor: and that the mutual forces of a current and a magnet are within certain
limits of current nearly proportional to the current. The speeds and currents I
employ in this apparatus are within these limits. Consequently in the apparatus
herein described the mean speed of the motor and disc is nearly proportional to
the current in the conductor 2, and the action of the device described above
is to regulate the rotation of the motor and disc so that its speed is always nearly
proportional to the current being supplied to the house.
The above described apparatus and mode of regulation may be modified in
various ways without departing from the nature of this invention. For example,

page_text: instead of using a permanent magnet of the horse-shoe form moving about a
fixed axis as shewn in Figures 1 and 2, I may employ a fixed permanent magnet
or magnets having a pair of movable pole pieces mounted on an axle moving in
fixed bearings; or I may connect the two movable pole pieces by a piece of
non-magnetic material so as to form a rigid system which can be carried on a
single point, by which means I secure greater freedom from friction, while the
combined action of the weight of the system and the magnetic forces of the
permanent magnets, control the motion of the moving system, so that it can only
take place about a fixed geometrical line as an axis.
I prefer to place the centre or point on which the system of pole pieces rests
as close as possible to the centre of gravity of the moving system, so that the
moving system is not thrown into oscillation by shocks or vibration of the frame
on which the pivot or centre rests.
Figures 3, 4 and 5 illustrate this construction. In these figures A A are fixed
permanent magnets, B B are fixed soft iron polar extensions, and CC are the
two pole pieces attached rigidly to one another by means of the non-magnetic
piece D. The parts C C and D D constitute a movable system which is supported
by a point K placed as near as possible to the centre of gravity of the system
resting on a fixed support E. Electrical connection is made with the movable
system by means of a spring F which is mounted on the fixed support E, and
bears upon a point or centre L placed in the line of the axis M N, about which
the moving system is adapted to rotate. G is the rotating disc, and H H is the
conductor that carries the current to be measured. The movable system carries
a contact piece of 2 which is caused by the motion of the movable system to make
contact with the two fixed contact terminals 01 02 respectively. M N are brass
screws or studs by means of which the moving system can be lifted off its pivot
and locked for transport. D is an adjustable weight provided for the purpose
of balancing the movable system.
The speed of rotation of the motor may also be regulated by so connecting
the contact pieces to the motor brushes that the speed of the motor is reduced by
short circuiting the armature: or the speed of the motor may be increased by
short circuiting a resistance inserted in the motor circuit.
Figure 6 illustrates diagrammatically the employment of both these methods.
In this figure the terminals marked and are the points at which the
current is brought into the house from the supply mains. G is the revolving
disc. and C is the movable magnetic system. H is a diagrammatic representation
of the lamps alight in the house. The whole current passes through the con-
ductor. The power to drive the motor is in this case taken from the supply
mains to the brushes 12 through the resistances R R2 and the arrangement
of the contacts is such that when the movable contact piece e rests against the
contact the motor armature is short circuited, and when the contact piece
rests against the contact g the resistance Re is short circuited. Thus for small
currents along the conductor and low motor speed the regulation of the
motor is effected by alternately short circuiting and opening the armature circuit
with a very large resistance (R¹ + R2) in the circuit, and a small motor current.
For large currents along the conductor and high motor speed the regulation
of the motor is effected by alternately short circuiting and opening the resistance
R2 the resistance R remaining constantly in the motor circuit. At some one
intermediate value of the current, the contact piece e will stand indifferently
between the contacts f and g, and the regulation may be made in either way.
In another arrangement of my apparatus illustrated in Figures 7 and 8, the
two movable pole pieces C C are made double-ended and are connected to each
ether by means of two stav pieces D D of non-magnetic material. The parts CC
and DD together with the movable contact pieces of o², constitute a movable
system which is carried centrally on a point K midway between the polar exten-
sions M N of the two fixed permanent magnets A A. The copper disc G revolves
between the two adjacent ends of the pole pieces C C on one side of the axis of

page_text: pivotation of the movable system, and the conductor H is coiled in the form of
à tlat spiral between the two adjacent ends of the pole pieces on the opposite
side of the said axis. The numerous turns of the flat spiral are designed to
multiply the action that would be produced on the magnetic system if only one
or a few turns are employed as in the apparatus of Figures 3, 4.
The direction of the rotation of the disc G and the direction of the flow of
the current in the conductor H are such that the movable system C C D D ¹³
will have a tendency to turn on the point K in one direction or the other according
as the action of the disc G on one end of C C is greater or less than the action
of the conductor H and vice versa.
As will be well understood, in lieu of a permanent magnet, an electro-magnet
may be employed in all cases where convenient or desirable,
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that I do
not claim broadly apparatus for measuring a supply of electricity of the type
in which the regulation of the supply of energy to an electric motor is effected
in such a manner that its speed is at all times proportional to the current which
the apparatus is intended to measure, but what I do claim is:-
1. In apparatus of the type herein before referred to for measuring a supply
of electricity, the combination of a rotating mass of electrically conducting
material driven by an electric motor, of a conductor carrying the current to be
measured, and of a single magnet movable about an axis regulating by means
of electrical contacts the supply of electrical energy to the motor, which magnet
is acted on directly and in opposite senses by the rotating mass and by the current
in the conductor, arranged and operating substantially as hereinbefore described.
2. Apparatus for measuring a supply of electricity constructed, arranged and
operating substantially as herein before described with reference to Figures 1
and 2 of the accompanying drawings.
3. Apparatus for measuring a supply of electricity constructed, arranged and
operating substantially as hereinbefore described with reference to Figure 6.
4. In apparatus of the type hereinbefore referred to in Claim 1 for measuring
a supply of electricity, the use of a fixed magnet with moveable pole pieces, in
the place of a moveable magnet as and for the purposes described.
5. In apparatus of the type herein before referred to for measuring a supply
of electricity, a fixed magnet with pole pieces freely movable about an axis in
which the movable system of pole pieces is carried on a single point near its
centre of gravity, and the axis of motion is determined by the magnetic forces,
substantially as hereinbefore described with reference to Figures 3, 4, 5 and
also to Figures 7, 8.
6. Apparatus for measuring a supply of electricity constructed, arranged and
operating substantially as described with reference to Figures 3, 4, 5.
7. Apparatus for measuring a supply of electricity constructed, arranged and
operating substantially as described with reference to Figures 7, 8.
Dated this 21st dow of Lu. 1800
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.