IMPROVEMENTS IN MEASURING AND RECORDING ELECTRIC CURRENTS AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1881

page_text: LETTERS PATENT to Joseph Wilson Swan of the Town and County of
Newcastle upon Tyne Chemist, for an Invention of "IMPROVEMENTS IN
MEASURING AND RECORDING ELECTRIC CURRENTS AND IN THE APPARATUS
EMPLOYED THEREIN."
PROVISIONAL SPECIFICATION left by the said Joseph Wilson Swan at the
Office of the Commissioners of Patents on the 16th December 1881.
JOSEPH WILSON SWAN of the Town and County of Newcastle upon Tyne
Chemist "IMPROVEMENTS IN MEASURING AND RECORDING ELECTRIC CURRENTS
AND IN THE APPARATUS EMPLOYED THEREIN
"
In my Patent dated 1st December 1880 No. 5004 I described an electric meter
intended chiefly to be used in connection with electric lamps. The apparatus
described in my said Specification is so constructed that it is necessary to have a
pair of wires extending between the meter and each of the lamps. My present
Invention is in part an improvement in that apparatus the improvement consisting
in the avoidance of the branch wires from individual lamps. I accomplish this
object by taking tho main conducting wire or a shunt from it round the several
electro-maguets which determine the engagement or disengagement of the inter-
mediato pawls with the counting mechanism, and I adjust the springs which
counteract the pull of these electro-magnets so that when the current for the supply
of one lamp is passing through the main wire or shunt only one of the magnet
armatures will be attracted from its inactive position and when current is
passing for the supply of more than one lamp the number of magnet armatures
rendered operative shall correspond with the number of lamps lighted.
The motor which actuates the counting mechanism may either be driven by a
spring or weight like an ordinary clock or by an electric current like an electric
clock such current being supplied either by a small local voltaic cell or battery, or
derived from the generator which supplies the electric lamps. In any case I prefer
that the motor should not be always in action but that it should be so arranged as
to commence action simultaneously with the coming into action of any of the

page_text: electro-magnets. A modification of this apparatus consists in the employment of
a solenoid in the circuit of the main conducting wire or in a shunt from it so
arranged that the position of the core of the solenoid which will vary with the
strength of the current passing through it shall connect together the motor and
counting mechanism so as to cause the rate of counting to correspond to the
number of lamps in use. Instead of indicating the number of lamps in use and
the time during which they are used by the purely mechanical means described
I sometimes vary the construction of the meter by the introduction into it of the
principle of electro chemical decomposition. I am aware it has been before
proposed to employ the voltamoter and also the electro-lysis of a solution of copper
as the basis of a meter to be used in connection with electric lamps but the manner
in which it has been proposed to employ this principle of measurement, namely by
placing the voltameter or copper cell as a shunt from the main conducting wire, is
wasteful of electric energy more particularly as regards the employment of the
voltameter, inasmuch as the electro-motive force necessary for the decomposition of
water is considerable, and even if only a small portion of the current supplied to
the lamps passes through the voltameter yet it is necessary in order to obtain the
requisite difference of potential on the positive and negative sides of the voltameter,
to interpose a resistance equivalent to this difference of potential in the main wire
extending between the terminals of the shunt in which the voltameter is situated.
To avoid this loss and to enable the principle of the voltameter to be utilised
without this disadvantage for the purpose contemplated I connect together in a
continuous line or series the electro-lytic apparatus made to vary automatically
and an automatically variable resistance and I connect the terminals of this
combined apparatus to the two main trunk wires in other words place them in
parallel arc with the lamps so that a constant electro motive force acts on the
terminals of the voltameter and resistance combined. The required automatic
variation of the resistance may be produced as follows but I do not confine myself
to this mode of making the automatically varying resistance as other modes of
effecting that object will readily suggest themselves to electricians.
The action of a solenoid in the circuit of the main wire causes a plunger to rise
or fall in a tube of mercury in proportion to the current in the main wire and so
as to make the mercury rise or fall and in doing so to short circuit or disconnect
branches taken from different lengths of the resistance coil these lengths being so
adjusted that the resistance of the coil shall diminish or increase by these short
circuitings or disconnections in steps corresponding to lamp units of current passing
in the main wire. Consequently the amount of gas evolved in the voltameter will
be proportional to the current in the main wire and to the number of lamps lit.
As the resistance in the voltameter circuit may be great it is possible to accomplish
the measurement by passing through the voltameter a small proportion of the total
current employed. The gas evolved in the voltameter may be made to cause the
periodical oscillation of a beam by the alternate filling or partial filling and
emptying of gas receptacles attached to the beam and immersed in the voltameter
liquid and the beam may in rising or in falling operate counting mechanism or the
kind usually employed in gas and water meters. Instead of the gas evolved by
the voltameter apparatus arranged as described it may be made to cause the
periodic rise and fall of a float and thus to cause a step by step action of counting
mechanism in the usual manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Joseph Wilson Swan in the Great Seal Patent Office ou the
16th June 1882.
JOSEPH WILSON SWAN of the Town and County of Newcastle upon Tyne
Chemist. "IMPROVEMENTS IN MEASURING AND RECORDING ELECTRIC CURRENTS
AND IN THE APPARATUS EMPLOYED THEREIN."
In the Specification of Letters Patent granted to me dated first December 1880
No. 5004 I described an electric meter intended chiefly to be used in connection
with electric lamps. The apparatus described in my said Specification is so
constructed that it is necessary to have a pair of wires extending between the
meter and each of the lamps. My present Invention is in part an improvement in
that apparatus the improvement consisting in the avoidance of the branch wires
from individual lamps. I accomplish this object by taking the main conducting
wire or a shunt from it round the several electro-magnets which determine the
engagement or disengagement of the intermediate pawls with the counting
mechanism and I adjust the springs which counteract the pull of these electro-
magnets so that when the current for the supply of one lamp is passing through
the main wire or shunt only one of the magnet armatures will be attracted from
its inactive position and when current is passing for the supply of more than one
lamp the number of magnet armatures rendered operative shall correspond with
the number of lamps lighted.
The motor which actuates the counting mechanism may either be driven by a
spring or weight like an ordinary clock or by an electric current like an electric
clock such current being supplied either by a small local voltaic cell or battery or
derived from the generator which supplies the electric lamps. In any case I prefer
that the motor should not be always in action but that it should be so arranged
as to commence action simultaneously with the coming into action of any of the
electro-magnets. A modification of this apparatus consists in the employment of
a solenoid in the circuit of the main conducting wire or in a shunt from it so
arranged that the position of the core of the solenoid which will vary with the
strength of the current passing through it shall connect together the motor and
counting mechanism so as to cause the rate of counting to correspond to the number
of lamps in use. Instead of indicating the number of lamps in use and the time
during which they are used by the purely mechanical means described I sometimes
vary the construction of the meter by the introduction into it of the principle of
electro-chemical decomposition I am aware it has been before proposed to employ
the voltameter and also the electrolysis of a solution of copper as the basis of a
meter to be used in connection with electric lamps but the manner in which it has
been proposed to employ this principle of measurement namely by placing the
voltameter or copper cell as a shunt from the main conducting wire is wasteful of
electric energy more particularly as regards the employment of the voltameter
inasmuch as the electro-motive force necessary for the decomposition of water is
considerable and even if only a small portion of the current supplied to the lamps
passes through the voltameter yet it is necessary in order to obtain the requisite
difference of potential on the positive and negative sides of the voltameter to
interpose a resistance equivalent to this difference of potential in the main wire
extending between the terminals of the shunt in which the voltameter is situated.
To avoid this loss and to enable the principle of the voltameter to be utilized
without this disadvantage for the purpose contemplated I connect together in a
continuous line or series the electrolytic apparatus and an automatically variable
resistance and I connect the terminals of this combined apparatus to the two main

page_text: trunk wires in other words in parallel are with the lamps so that a constant electro
motive force acts on the terminals of the voltameter and resistance combined. The
required automatic variation of the resistance may be produced as follows but
I do not confine myself to this mode of making the automatically varying
resistance as other modes of effecting that object will readily suggest themselves to
electricians.
The action of a solenoid in the circuit of the main wire causes a plunger to rise
or fall in a tube of mercury in proportion to the current passing in the main wire
to short circuit or
and so as to make the mercury rise or fall and in doing so
disconnect branches taken from different lengths of the resistance coil these lengths
being so adjusted that the resistance of the coil shall diminish or increase by these
short circuitings or disconnections in steps corresponding to lamp units of current
passing in the main wire. Consequently the amount of gas evolved in the
voltameter will be proportional to the current in the main wire and to the number
of lamps lit. The gas evolved in the voltameter may be made to cause the
periodical oscillation of a beam by the alternate filling or partial filling and
emptying of gas receptacles attached to the beam and immersed in the voltameter
liquid and the beam may in rising or in falling operate counting mechanism of the
kind usually employed in gas and water meters. . Instead of the gas evolved by
the voltameter apparatus arranged as described being made to oscillate the beam
as described it may be made to cause the periodio rise and fall of a float and thus
to cause a step by step action of counting mechanism in the usual manner.
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is :-
First The mode of avoiding the employment of branch wires between the
individual lamps and the electro-magnets of the meter in electric meters of the
class described in my former Specification No. 5004, 1880. as herein before
described.
Second-In electric meters wherein a motor and a counting mechanism are
employed the connection of the two by means of a solenoid in the circuit of the
main conducting wire or in a shunt from the main line so arranged as to cause the
rate of counting to correspond with the number of lamps in use as herein before
described.
in
Third-In electric meters which depend upon the principle of electrolytic action
the combination of an automatically variable resistance connected series
with the electrolytic cell and connected in multiple are with the lamps and
arranged so as to actuate and give a reciprocating motion to a balance beam and
through it to give motion to counting mechanism so as to cause the rate of counting
to
o be varied with the work done as herein before described.
In witness whereof I the said Joseph Wilson Swan have to this my
Specification set my hand and seal this Fourteenth day of June One
thousand eight hundred and eighty two.
JOSEPH WILSON SWAN. (L.S.)