Improvements in Electric Meters.
Year: 1889

page_text: Date of Application, 4th June, 1889
Complete Specification Left, 4th Mar., 1890-Accepted, 19th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in Electric Meters.
ALAN ARCHIBALD CAMPBELL SWINTON Engineer, 66 Victoria Street London S.W
do hereby declare the nature of this invention to be as follows:-
11
This invention relates to improvements in meters for measuring alternating or
intermittent electric currents.
According to my invention I cause a suitable body to vibrate reciprocally in unison
with the alternations or periods of the current, the amplitude of such vibrations being
proportional to the strength of the said current and I cause the vibrations of the
body to actuate a suitable recording or counting apparatus in such a manner that the
said counting apparatus is moved forward at each vibration through a space propor-
tional to the amplitude of the vibration and consequently to the strength of the
current, so that the periodicity being constant the counting apparatus in a given time
is moved through a space proportional to the total current that has passed during
that time.
According to one arrangement for carrying out my invention I pass the current to
be measured or a proportion of it through an electro magnet or solenoid which has for
armature the free end of a reed or tongue the other end of which is firmly fixed, and
which is timed so that its natural time of vibration corresponds with the period of
the current to be measured. To the free end of the reed I attach a light spring
which bears upon the smooth periphery of an iron disc or cylinder mounted on an
axis arranged in connection with a counter to record the number of revolutions it
mákes in a given time, and round the iron disc I arrange a coil of wire through.
which I also pass the current to be measured or a portion of it or another alternating
or intermittent current of the same periodicity and in the same or exactly opposito
phase, so that the portion of the edge of the disc where the spring rubs is alternately
magnetised and demagnetised with each fluctuation of the current and the adhesion
between the disc & spring is consequently increased or lessened at each period.
The effect of the alternating or intermittent current passing through the electro
magnet or solenoid is to cause the free end of the reed to execute vibrations in unison
with the alternations or periods, and by suitably proportioning the surface of the
reed and taking advantage of the resistance of the air the amplitude of each
vibration can be made proportional to the strength of the said current.
The vibrations of the reed are communicated to the light spring which working
backwards and forwards with each vibration on the periphery of the iron dise and.
being alternately caused to adhere and leave go of the latter owing to the alternate
magnetisation & demagnetisation of the disc, acts like a ratchet and causes the
disc to revolve on its axis in one continuous direction at a speed proportional to the
amplitudes of the vibrations of the reed and consequently to the strength of the current
that is passing.
In place of a reed a stretched wire or band held at both ends and vibrating at its
centre may be employed or a tympanum held round its circumference and vibrating
at its centre may be used. Where a band is employed the electro magnet or solenoid
may be dispensed with and the. requisite vibration obtained. by arranging the band
in a suitable permanent or other magnetic field and passing the alternating or inter-
mittent current through the band, a suitable spring or weight being employed to keep
the band at the requisite degree of tension irrespective of any elongation in its
length that may be occasioned by its becoming heated by the current.
The magnetic clutch arrangement as described above may also be dispensed with

page_text: and an ordinary friction clutch of delicate construction employed or a pawl and a
wheel with very fine ratchet teeth may be employed instead. The magnetic clutch is
however preferable where a considerable range is required..
.
Dated this 3rd day of June 1889
A. A. C. SWINTON.
COMPLETE SPECIFICATION.
Improvements in Electric Meters.
ALAN ARCHIBALD CAMPBELL SWINTON of 66 Victoria Street London S.W. Engineer
do hereby déclare 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 improvements in meters for measuring alternating, or.
intermittent electric currents.
24
According to my invention I cause a suitable body to vibrate reciprocally in unison,
with the alternation or periods of the current, the amplitude of such vibrations being.
approximately proportional to the strength of the said current, and I cause the
vibrations of the body to actuate a suitable recording or counting apparatus in such
a manner that the said counting apparatus is moved forward at each vibration,.
through a space approximately proportional to the amplitude of the vibration and
consequently to the strength of the current; so that the periodicity being constant,
the counting apparatus in a given time is moved through a space approximately
proportional to the 'total current that has passed during that time.
*
According to one arrangement for carrying out my invention I pass the current to
be measured or a definite fraction of it through an electro magnet or solenoid S
(fig. 1) which has for armature the free end of a reed or tongue R, the other end
of which is firmly fixed at G and which is timed so that its natural time, of vibration.
corresponds with the period of intermittence or alternation of the current to be
measured. To the free end of the reed R is attached a light spring carrying a small
iron piece A which bears upon the smooth periphery of an iron disc or cylinder, D
mounted upon an axis arranged in connection with a counter B to record, the number
of revolutions that the disc makes in a given time. Round the iron disc but without,
touching the same is arranged a coil of wire C through which is also passed the
current to be measured or a fraction of it or another alternating or intermittent.
current of the same periodicity so that the portion of the edge of the disc D where A
rubs is alternately magnetised and demagnetised with each fluctuation of the current,.
and the adhesion between the disc D and the piece A is consequently increased or
lessened at each fluctuation.
The effect of the alternating or intermittent current passing through the electro
magnet S is to cause the free end of the reed R to execute vibrations in unison with
the alternations or periods of the current, and by attaching to the reed R. a plate, E,
(fig! 2) of mica or other suitable' light material, and proper area, and taking
advantage of the resistance of the air, or if the whole apparatus be immersed in a
suitable fluid such as paraffine oil by utilising the resistance offered by such a fluid,,
the amplitude of such vibrations can be made approximately proportional to the
strength of such current.
*14*
The vibrations of the reed Rare communicated to the spring and rubbing piece A
which working backwards and forwards with each vibration on the periphery of the..
dise Cand being alternately caused to adhere to and leave go of the latter, owing to.
the alternate magnetisation and demagnetisation of the disc acts like a ratchet and
causes the "dise to revolve on its axis in one continuous direction at a speed
approximately proportional to the amplitude of the vibrations of the reed and con-
sequently to the strength of the current that is passing. In some cases accuracy in
Cre

page_text: this respect can be increased by mounting vanes or blades F F of mica or other
light material upon the axis of the disc as shown in Fig. 2.
In place of the reed a stretched wire or band (as R in fig. 3) held at both ends G.
and H and vibrating at its centre may be employed or a thin metal or other
tympanum or diaphragm held round its circumference and vibrating at its centre.
may be used.
Where a wire or band is employed the electro-magnet S may be dispensed with:
and the requisite vibration obtained by arranging the apparatus as shown on fig. 4
where the band R is placed in a strong permanent magnetic field between the poles
of the magnets M. M. etc., and passing the current to be measured through the band
itself from T to T, the band being kept stretched to the proper degree by a suitable
weight W and prevented from.. moving at its lower extremity by a guide H, or a
spring being used for this purpose, so that the requisite degree of tension may be
maintained irrespective of any elongation of the band due to its becoming heated by
the current or otherwise.
In this arrangement, the rate of the vibrations of the band will be exactly one half
that in the previous cases presuming the rate of alternation in the current to remain
the same, and the spring A may be replaced by a small permanent magnet hinged at
one end to the centre of the band, and bearing at the other on the periphery of the
disc D, the magnetism of A causing it to adhere to D when the current in the coil C
is in such a direction to induce a pole D opposite to that in A and to leave go when
the poles are similar.
Another arrangement is that shewn in fig. 5 where the coil C surrounds the reed R
without touching the latter and the reed R is caused to vibrate by its varying
attraction on the iron yoke piece J. Here the rubbing piece A may be dispensed
with and rotation of the disc obtained by the end of the reed R which is alternately
magnetised and demagnetised with the fluctuations in the current, being brought into
close propinquity to the edge of the disc as shown in fig. 6, the movement of the reed
and the lag in the magnetism induced in the disc causing the latter to rotate.
It is obvious that other arrangements for causing the movements of the reed to be
transmitted to the disc may be employed. For instance as shown in Fig. 7 a hinged
piece of iron A may be used in place of the spring herein before described, or as
shown in fig. 8. a ratchet operating a wheel with exceedingly fine teeth, or a friction
clutch arrangement may be used. Another plan would be to utilise the currents of
air due to the vibrations of the reed, band or tympanum to operate a small windmill
connected to the counter.
In most cases I have found it convenient to pass the current to be measured or
a definite proportion of it through the electro-magnet or solenoid S, and obtain the
required current for the coil C by connecting the latter in a shunt across the positive
and negative conductors of the main supply like an ordinary voltmeter, but it is
clear that these conditions may be reversed, or the current to be measured may be
passed through both electro magnet and coil in series or in parallel.
Having now particularly described and ascertained the nature of my 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 measuring alternating or intermittent currents of
electricity the employment of a body vibrating in unison with the alternations of
pulsations in the current and operating a counting or recording device.
(2) In an electric meter for measuring alternating or intermittent currents
of electricity the employment of a reed, a band, a tympanum, or a diaphragm,
vibrating with the alternations or pulsations in the current and operating a counter
or recording device substantially as set forth.
(3) The combination with the reed or other vibrating body of the magnetic ratchet
or clutch acting on a disc or cylinder with a smooth periphery, and operating a
counter substantially as described.

page_text: (4) The combination with the reed or other vibrating body and the counter of
vanes to offer a resistance in air or other fluid for the purpose of rendering the
readings of the counter proportional to the current, substantially as described.
(5) The several arrangements of electric measuring apparatus wherein a body
vibrating with the alternations or pulsations in the electric current is employed,
substantially as hereinbefore described with reference to the several figures of the
accompanying drawings.
Dated this 4th day of Mana 1000