IMPROVE- MENTS RELATING TO ELECTRIC METERS
Year: 1885

page_text: I, SYDNEY FERRIS WALKER, of 195 Severn Road, Cardiff, Glamorganshire,
Electrical Engineer do hereby declare the nature of my invention for IMPROVE-
MENTS RELATING TO ELECTRIC METERS to be as follows:-
My invention relates to apparatus for measuring, registering or indicating the
electric energy supplied from an external source to a house, or to any part of an
electric circuit for lighting or other purposes.
In ordinary cases in which electricity is supplied from a central source or station
for lighting houses or for other purposes, the householder or consumer does not
need to know in what proportion the two factors vizt the electro-motive force and
the current exist in the product of those two quantities, that is to say, the
electrical energy for which he has to pay.
.
I therefore do not intend my said apparatus to measure or indicate either
electro-motive force (E) or current (C) separately but to measure and indicate the
energy which is the product of the electro-motive force multiplied into the
current (Ex C).
My apparatus is designed to register or indicate the electric energy supplied
from the external source to the branch or part of the circuit in which it placed
in such a manner that, whether the supply is varied by either external or internal
circumstances, the meter will accurately record or indicate the amount used by the
consumer at, or during, any period of time..
I will hereinafter refer to the use of my apparatus only in connection with an
electric lighting circuit. For this purpose my improved meter or apparatus consists
essentially of a rotating armature included in the circuit of the lamps and an
electro-magnet or electro-magnets included in a shunt taken across the said circuit.
The armature is geared in connection with any suitable index or counter or
indicating apparatus. The resistance of the said shunt is constant so 'that while
the difference of potential at the points of junction with the mains is constant the
current in the shunt will be constant and the intensity of the magnetic field will
be constant except as it may be affected by the counter electro-motive force
generated in the armature and the reactions between the said armature and
magnets.
The lamps are in parallel so that the resistance varies inversely in proportion
to the number of lamps turned on at any time. Therefore the current will he

page_text: proportional to the electric work being done at any time. It will be readily
understood that the variation of resistance in the lamp circuit is the only internal
circumstance that will affect the current flowing through the armature. The
variations from external circumstances will be due to the conditions of supply
which will affect the potential at the junction of the mains with the internal
circuit. If the electro-motive force or E. M. F. at this point increases or diminishes,
the current in the shunt and consequently the magnetic field will vary and the
current in the lamp circuit will vary. independently of the resistance therein.
Now it is obvious that either circumstance will affect the speed of the armature
whose motion is caused by the electro-magnetic couple whose force is the reaction
between the field magnets and the armature that is to say the speed of the
armature will be proportionate to the product of the intensity of the field and the
current in the armature; therefore it will be proportionate to the amount of
electric energy (Ex C) being supplied at any moment and therefore the meter
should at all times correctly indicate the amount supplied to the consumer.
The relative proportions of the resistance in the large circuit and shunt will be
adapted to the conditions of working in each particular case.
I prefer that the armature shall be the revolving portion of the meter as above
described but in some instances I arrange the electro-magnets to revolve, and
in some instances I shunt the revolving part instead of the fixed part of the
apparatus..
Switches and other devices for turning the current on and off or regulating the
same will be provided as may be required.
'

page_text: "
I, SIDNEY FERRIS WALKER, of Cardiff, in the County of Glamorgan, Electrical
Engineer, do hereby declare the nature of my invention for IMPROVEMENTS
RELATING TO ELECTRIC METERS" 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 apparatus for measuring, registering or indicating the
electric energy supplied from an external source to a house or to any part of an
electric circuit for lighting or other purposes.
In ordinary cases in which electricity is supplied from a central source or station.
for lighting houses or for other purposes, it is not necessary that the householder or
consumer should know in what proportion the two factors, viz:-the electro-motive
force and the current exist in the product of these two quantities, that is to say,.
the electrical energy for which he has to pay.
I, therefore, do not intend my said apparatus to measure or indicate either electro-
motive force (E) or current (C) separately, but to measure or indicate energy which:
is the product of the electro-motive force multiplied into the current (E x C).
My apparatus is designed to measure, register or indicate the electrical energy
supplied from the external source to the branch or part of the circuit in which it
is placed, in such a manner that, whether the supply is varied by external or by
internal circumstances, the meter will accurately record or indicate the amount
used by the consumer at, or during, any period of time.
I will hereinafter refer to the use of my apparatus only in connection with an
electric lighting.circuit. For this purpose, my improved meter or apparatus consists
essentially of an electro-magnet or electro-magnets included in the circuit of the
lamps, and a rotating armature included in a shunt taken across the said circuit or
in parallel with the lamps. Or, if desired, the armature is included in the lamp-
circuit and the field magnet or magnets in the shunt. The armature is in connec-
tion with any suitable counter or indicating apparatus.
The resistance of the said shunt is constant, so that, while the difference of
potential at the points of junction with the mains is constant, the current in the
shunt will be constant, except as it may be affected by the counter electro-motive
force generated in the armature and the reactions between the said armature and
magnets.
The lamps are in parallel, so that the resistance in the lamp-circuit varies in
inverse proportion to the number of lamps turned on at any time. Therefore the
current will be proportional to the electric work being done at any time. It will
be readily understood that the variation of resistance in the lamp-circuit is the only
internal circumstance that will affect the intensity of the magnetic field. The
variations from external circumstances will be due to the conditions of supply,
which will affect the electro-motive force of the supply, that is to say, the difference
of potential at the points of junction of the lamp-circuit with the mains. If this
electro-motive force or E. M. F. increases or diminishes, the current in the shunt
will vary and the current in the lamp-circuit will also vary independently of the
resistance therain,

page_text: Now it is obvious that either circumstance will affect the specd of the armature
the motion of which is caused by the electro-magnetic couple whose force is the
reaction between the field-magnets and the armature, that is to say, the speed of
the armature will be proportionate to the product of the intensity of the field and
the current in the arinature, and will consequently be proportionate to the amount
of electric energy (Ex C) being supplied at any moment; therefore the meter
should, at all times, correctly indicate the amount supplied to the consumer.
The relative proportions of the resistance in the lamp-circuit and shunt will be
adapted to the conditions of working in each particular case.
I prefer that the armature shall be the revolving portion of the meter as above
described, but, in some instances, I arrange the electro-magnets to revolve, and I
sometimes shunt the fixed part instead of the revolving part of the apparatus.
In the accompanying drawing, I have illustrated the manner in which the
electrical connections are made when the armature is arranged in a shunt.
a, a are the mains; bis the lamp-circuit, and b¹, b₁ are the lamps, arranged in
parallel therein. c, c are the field-magnets, which are included in the circuit b. dis
the armature, which is included in the shunt e taken across the lamp-circuit, and
which is connected with a suitable counter or indicator f through the medium of
the worm g fixed on the armature-shaft and gearing with the worm-wheel h fixed
on the driving shaft or spindle i of the said counter.
.
Switches and other devices for turning the current on and off or regulating the
same will be provided as may be required.
The counter is so constructed that it will indicate thousandths, hundredths,
tenths, units, tens; hundreds, and so on, and I prefer that the unit should be that
adopted by the Board of Trade, viz:-1000 Watts. It is obvious that the gearing
connecting the shaft of the motor with the counter must be suitably arranged and
proportioned to effect this result. The said gearing should, moreover, be so made
as to diminish the friction as much as possible.
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 what
I claim is
The improvements relating to apparatus for measuring, registering or indicating
electric energy and consisting essentially in the employment of an electric motor
the fixed and rotating parts of which are arranged in different parts of a divided
circuit in combination with a counter or indicating apparatus, substantially as set
forth.