Improvements in Electric Meters.
Year: 1889

page_text: Date of Application, 2nd Nov., 1889
Complete Specification Left, 19th July, 1890-Accepted, 23rd Aug.,
1890
PROVISIONAL SPECIFICATION.
Improvements in Electric Meters.
We, JOSEPH OULTON, of 232, Otley Road Bradford in the County of York, Clock
Maker, and JOSEPH EDMONDSON, of 36 Sunbridge Road, Bradford, in the County
aforesaid, Electric Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates mainly to Electric Meters in which the current to be
imeasured is made to retard or accelerate the vibrations of a pendulum or chrono-
metric balance, the amount of such retardation or acceleration being the measure of
the current consumed.
Instead of a single magnet on or connected to, or itself forming, a torsion balance
as described in the specification of a patent No. 14843 granted to us on the 16th
October 1888, we use a pair or pairs of magnets placed astatically" that is with
their poles reversed, so as to neutralise the influence of the earth's magnetism, and to
reduce the effect of other external influences.
We also substitute a pair of solenoids placed astatically for the single solenoid
on the torsion balance as described in the said specification.
In place of the fixed solenoid or solenoids influencing the torsion balance (through
the magnet or solenoid attached to it) as described in the said specification, we use a
single conductor consisting either of one wire (or its equivalent) or of several wires
(or their equivalents coupled in parallel) placed so as to influence the magnets or
solenoids attached to the balance. Such conductor may be either straight or bent to
and fro, over and under, the said magnets or solenoids, so as to increase the influence
of the current; or it may be passed in parallel above and below in different propor-
tions or at different distances, so as to diminish the said influence.
In the case of a pendulum we use either a horse shoe magnet, or astatic magnets
instead of the straight magnet (whether single or compound) hitherto used; and
we carry the current in the vicinity of the poles by a single conductor as before
described, mutatis mutandis.
The calibration of the instrument may be effected by varying the distance of the
aforesaid conductor (or a part of it) from the magnet or solenoid to be influenced by
the current to be measured.
in order the better to protect the magnets or solenoids on a torsion balance from
external magnetic influence, we surround them with iron, either fixed and having the
balance rotating within it, or forming the whole or a portion of the balance.
We correct the want of proportionality in the record of Watt meters by a supple-
mentary solenoid or coil on the pendulum or balance, through which is passed a small
fraction of the current to be measured. The influence of the main current on this
solenoid being in proportion to the square of the fraction of the current passing
through the latter, will correct the small error which would otherwise arise in the
register. In Coulomb meters for alternating currents we use a similar supplementary
current through a solenoid or coil either on, or fixed in the vicinity of the balance or
pendulum.
For the purpose of adapting electric meters of any kind without recalibration to
currents of different electro motive force, we insert, at some convenient point for
driving the registering train, a change wheel, which we term a "volt-wheel." By
preference the number of teeth in this wheel is the same as the number of volts in the
electro motive force of the current to be measured.
Dated the 28th day of October 1889
WALTER
BRIERLEY,
Central Chambers, Halifax, Agent for the Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Meters.
We JOSEPH OULTON, of 232. Otley Road Bradford, in the County of York, Clock
Maker and JOSEPH EDMONDSON, of 36 Sunbridge Road, Bradford, in the County,
aforesaid, Electric Engineer, 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 Electric Meters in which the current to be measured is
made to retard, or accelerate the vibrations of a pendulum, or chronometric balance,
the amount of such retardation, or acceleration being the measure of the current
consumed.
Instead of a single straight magnet on, or connected to, or itself forming a torsion
balance as described in the specification of a patent No. 14843 granted to us on the
16th October 1888 we use a magnet, or inagnets placed "astatically" so as to
neutralise the influence of the earth's magnetism, and to reduce the effect of other
external influences. We also substitute a solenoid, or solenoids placed astatically,
for the single straight solenoid on the torsion balance, as described in the said
specification.
In place of the fixed solenoid, or solenoids influencing the torsion balance (through
the magnet, or solenoid attached to it) as described in the said specification, we use a
single conductor, consisting of either one wire (or its equivalent) or of several wires
coupled in parallel (or their equivalents) placed so as to influence the magnets, or
solenoids attached to the balance. Such conductor may be either straight, or bent to
and fro, over and under the said magnets or solenoids, so as to increase the influence
of the current, or it may be passed in parallel above and below, in different propor-
tions, or at different distances, so as to diminish the said influence.
The calibration of the instrument may be effected by varying the distance of the
aforesaid conductor (or a part of it) from the magnet or solenoid to be influenced by
the current to be measured.
In order the better to protect the magnets on the balance from external magnetic
influence, we surround them with iron, either fixed, and having the magnets or
solenoids rotating within it, or forming the whole, or a portion of the balance.
We correct the want of proportionality in the record of Watt meters by a supple-
mentary solenoid or coil on the pendulum or balance through which is passed a small
fraction of the current to be measured. The influence of the main current on this
solenoid being in proportion to the square of the fraction of the current passing
through the latter, corrects the small error otherwise arising in the register.
Such being the nature and object of our invention the following is a complete
description of same reference being had to the accompanying drawings in which the
same numbers refer to the same parts throughout.
Fig. 1 is a plan and Fig. 2 a front elevation of astatic magnets and a single con-
ductor as used in our invention. To the torsion balance 1 the permanent magnets 2.3
are attached by any convenient method. They are separated from each other by the
pillar 4 which may be of iron (in which case it forms a yoke between the magnets)
or of non-magnetic material. The single conductor 5 is, in this case carried between
the astatic magnets, but it might be placed either above or below them, in which
position the influence on the vibrations of the balance would be much reduced.
In Fig. 3 the conductor is carried both between and above and below the magnets,
the portions marked 5ª and 5' being smaller and carrying less current than the main
portion 5 passing between the magnets, and diminishing the effect upon the vibrations
of the balance in proportion to their size and their distance from the magnets. They
thus afford a means of calibrating the instrument.
In Fig. 4 the conductor after passing between the magnets is split and returned,
one half above and the other half below them, thus increasing the effect on the
vibrations of the balance. These portions (5° and 5") of the conductor afford a means

page_text: of calibrating the instrument by varying their distance from the magnets. Instead
of two straight magnets we may use two horse shoe magnets placed as in Fig. 5.
One of these may be ommitted without affecting the astatic quality of the
arrangement.
The magnets in any of these arrangements may be replaced by solenoids or coils
or simple conductors placed astatically and receiving their current through mercury
cups; in which case the fixed conductor will be replaced by a permanent magnet
or magnets..
Fig. 6 illustrates in plan our method of protecting the magnets from external
influence by surrounding them with iron.
Fig. 7 shows the same in front elevation. 7.7 are rings of iron suspended con-
centrically by plates 6. 6 of non magnetic metal which also carry the magnets 2.3
with the pillar or yoke 4, the whole suspended by the torsion spring 8 and
forming the balance." The conductor 5 is carried between the iron rings, and as
before, between the magnets.
It will be evident that the rings might, if preferred, be fixed with magnets
(attached to the balance as in Fig. 1 and 2) or solenoids vibrating concentrically
within them.
A Watt meter constructed as described in our specification No. 14843 of the
year 1888 will measure an electric current proportionally only within certain
limits. There is an error, which within those limits is so small that it may be
disregarded, but which increases with the current in an increasing ratio. It arises
from the law that the force of the torsion spring producing the vibrations of the
balance is proportionate to the square of the number of vibrations in a given.
time.
=
If therefore a = the normal number of vibrations and b the number to be added
by the current under measurement, the force required to produce the latter will be
the difference between a² and (a + b) which difference 2ab+. The force
of the current however, being equal to 2 a b + is absolutely correct only when
unity. Thus if the normal speed of the balance is 1000 vibrations per hour
and it is calibrated to give one additional vibration per hour for one ampère of
current the force required to produce this vibration for each ampère of current
will follow the following series.
b =

page_text: .
We correct in a Watt meter according to our invention by adding to the high
resistance coil a supplementary coil or conductor carrying such small fraction of
the current to be measured as is required for the purpose." If the high resistance
coil be on or composing the balance this supplementary current may be conveyed
by means of wires dipping into mercury cups'as described in our aforesaid specification
No. 14843 of the year 1888.
It will be evident that this method of correcting the error is equally applicable
to Watt meters in which the effect of the current upon the vibrations of pendulums
swinging under the influence of gravitation is the basis of measurement.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. In Electric Meters in which the vibrations of a torsion balance are the basis
of the measurement we claim the use of astatic magnets or solenoids on or in con-
nection with the said balance.
2. In Electric Meters in which the vibrations of a torsion balance are the basis
of the measurement, we claim. The use of a torsion balance carrying a magnet
or magnets or a solenoid or solenoids in combination with a single conductor as
herein described and illustrated and carrying the current to be measured for the
purpose of influencing the rate of vibrations of the said balance.
3. In Electric Meters in which the vibrations of a torsion balance are the basis
of the measurement we claim the use of a ring or rings of iron concentrically
suspended on or forming the whole or a portion of the balance and concentrically
surrounding the magnet or magnets, solenoid or solenoids upon the said balance,
for purpose herein set forth.
4. In Electric Watt Meters in which the vibrations of a torsion balance or of a
pendulum vibrating under the influence of gravitation are the basis of the measure-
ment we claim the use of a high resistance (or volt) coil and a supplementary
coil or conductor, the latter carrying a fraction of the current to be measured, for
the purpose of making the register proportional to the current.
Patch the
JOSEPH OULTON.
JOSEPH EDMONDSON.
By their Agent, Walter Brierley,
Central Chambers, Halifax.