Improvements in Electricity Meters.
Year: 1891

page_text: Date o Application, 23rd Oct., 1891
Complete Specification Left, 23rd July, 1892-Accepted, 27th Aug.,
1892
PROVISIONAL SPECIFICATION.
Improvements in Electricity Meters.
We, SIEMENS BROTHERS & Co. LIMITED, of 12 Queen Anne's Gate,
Westminster, in the County of Middlesex and FRANCIS GIBSON BAILY, of
Ventnor Cottage, Mount Street, Charlton, in the County of Kent, Electrical
Engineers, do hereby declare the nature of this invention to be as follows:-
:-
This invention relates to an instrument which may be used as a volt meter or as
an ammeter, the winding being arranged for passage of a small current in the
former case and of a large current in the latter case. It is of simple construction,
little liable to derangement or error, its moving parts are very light, and its indi-
cations being given on a large scale, are easily read; it is moreover suited for
measurement of either continuous or alternating currents. The current to be
measured is passed through a conductor of spiral form, which may be a flat bar
of copper bent or cut to the desired shape, one revolution or part of a revolution
of a volute or plane spiral.
It may also be built up of several bars or wires forming several revolutions of a
volute, successively traversed by the current.
At or near the origin of the spiral is pivotted the axis of an index, which carries
a soft iron armature in the shape of a deep fork embracing the spiral bar, one
prong of the fork being on each side of the bar, but without touching it. The
armature is counterbalanced by a weight on the opposite end of the index, and the
axis of the index is attached to the inner end of a volute spring the outer end of
which is fixed. When an electrical current is transmitted through the spiral, the
closed end of the armature fork is attracted towards the spiral, and consequently
the index is made to make a partial revolution in opposition to the spring until the
closed end of the fork comes to such a position relatively to the spiral that the
tendency to move the index farther round is just balanced by the torsive strain
exercised by the spring. The closed end of the fork may be either at the end
next the axis or at the end farthest from the axis. In the former case, the scale
is such that the index points to the lowest indications when the armature is
embracing that part of the spiral which is farthest from the centre.
In the latter
case the index points to the lowest indications of the scale when the armature is
embracing the part of the spiral nearest to the centre.
Dated this 23rd day of October 1891.
IMD AV
ADEX & IMP
BEL
IMDA V
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Electricity Meters.
We, SIEMENS BROTHERS & Co. LIMITED, of 12, Queen Anne's Gate,
Westminster in the County of Middlesex, and FRANCIS GIBSON BAILY, of
Ventnor Cottage, Mount Street, Charlton in the County of Kent, Electrical
Engineers, 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 an instrument which may be used as a volt meter, or as
an ammeter. The winding being arranged for passage of a small current in the
former case and of a large current in the latter case. It is of simple construction,

page_text: little liable to derangement or error, its moving parts are very light, and its indi-
cations being given on a large scale, are easily read; it is moreover suited for
measurement of either continuous.or alternating currents.
Fig. 1 of the accompanying drawings represents in front view one construction
of instrument according to this invention. The current to be measured for
which A and B are the leads is passed through a conductor C of spiral form,
which may
be a flat bar of copper bent or cut to the desired shape, one revolution
or part of a revolution of a volute or plane spiral.
At or near the origin of the spiral is pivotted the axis D of an index I which
carries a soft iron armature in the shape of a deep fork embracing the spiral bar,
one prong of the fork being on each side of the bar, but without touching it as
shewn in section in Fig. 2. The armature is counterbalanced by a weight F on
the opposite end of the index, and the axis D of the index is attached to the inner
end of a volute spring S the outer end of which is fixed. When an electrical
current is transmitted through the spiral, the closed end of the armature fork is
attracted towards the spiral, and consequently the index is caused to make a partial
revolution in opposition to the spring S until the closed end of the fork comes to
such a position relatively to the spiral that the tendency to move the index farther
round is just balanced by the torsive strain exercised by the spring. The closed
end of the fork may be either at the end next the axis as shewn in Fig. 2 or at
the end farthest from the axis as shewn in Fig. 4. In the former case, the scale
is such that the index points to the lowest indications when the armature is
embracing that part of the spiral which is farthest from the centre. In the latter
case the index points to the lowest indications of the scale when the armature is
embracing the part of the spiral nearest to the centre.
The spiral may be of the shape shown in Fig. 3 consisting of a coil of
insulated wire wound on a bobbin.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
An electricity meter constructed and operating substantially as described with
reference to the accompanying drawings.
Dated this 23rd day of July 1892.