Improvements in Electricity Meters.
Year: 1899

page_text: Date of Application, 29th Aug., 1899-Accepted, 4th Nov., 1899
Improvements in Electricity Meters.
We, WALTER CLAUDE JOHNSON and THOMAS JOHN MURDAY, both of Victoria
Works, 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 electricity meters of the kind described in the Speci-
fication of Letters Patent No. 12390 of 1896 the object of our invention being
to provide in a meter of this class for recording watts, a Watt meter, which
is extremely sensitive and in which the hand or pointer has equal movements for
equal variations of current at all points of the scale.
The invention also comprises means for reducing to a minimum the quantity
of current necessary for operating the meter.
According to this invention the fine wire coil of the Watt meter instead of
being pivoted within the coarse wire coil, as has heretofore been usual, is arranged
around the outside of the said coarse wire coil which arrangement greatly facili-
tates the mounting of the fine wire coil and also enables the circuit wires to be
more readily connected therewith.
In order to economize current we provide that the current shall only flow
through the fine wire coil of the Watt meter at such time as the finger or pointer
of the said Watt meter is released by the clamping device which normally holds
the same.
In the accompanying drawings,―
Figure 1 is a sectional rear elevation of a meter described in the specification
before referred to, having our improvements applied to it:
Figure 2 is a sectional plan of the same;
Figure 3 is a sectional side elevation of the Watt meter drawn to a larger scale
than Figures 1 and 2.
a is the frame of the meter which is mounted upon a box b and c is the casing
which encloses the meter mechanism.
d is the pendulum which serves for controlling the operation of the meter and
which is operated by the electromagnet e, the circuit of which includes a resist-
ance e¹.
ff are the springs of the contact making and breaking device which are
operated by the pendant or trip piece 9 upon the pendulum. h is the arm rotated
by the pendulum through the medium of a ratchet wheel ¹ and a pawl 2. i is
the recording lever the movements of which are produced by the rotation of the
arm hand which operates upon the first wheel of the recording train, and j is
the "feeler" fixed to the said recording arm and serving by contact with the
finger k of the Watt meter to control the position of the recording lever i rela-
tively with the arm h.
7 is the clamping or gripping device which serves to hold the said hand k against
movement by the contact of the feeler therewith, the said clamping device being
operated by a pin m on the rotary arm h acting against the lever n having an
extension n¹ connected with the said gripping device.

page_text: 3. The improved electricity meter constructed, arranged and operating sub-
stantially in the manner hereinbefore described and illustrated in the accompany-
ing drawings.
1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.