Improvements in Electric Meters.
Year: 1893

page_text: Date of Application, 11th Apr., 1893
Complete Specification Left, 11th Jan., 1894-Accepted, 17th Feb., 1894
I JOHN WILLIAM JONES of 13 Dornton Road Balham in the County of Surrey
Electrical Engineer do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in electric meters of the class described in
Specifications 677081 and 885687 & which depend for their action on the
difference of rate of two clocks which difference is caused by the current to be
measured and is proportional to the current measured; the accuracy of such
instruments will therefore depend largely upon the synchronism of the two clocks
when no current is flowing as any deviation will be registered as if it were caused by
current.
The method I employ for overcoming this difficulty is to fix to each pendulum
or other reciprocating part a small magnet the magnets being arranged in such a
position relative to each other that they exert a small attractive or repulsive force
on one another the effect of this arrangement will be to keep the pendulums in such
a phase that the change of attraction & repulsion is a minimum.
Dated this Tonth dow of An 1902
Improvements in Electric Meters.
I, JOHN WILLIAM JONES, of 13 Dornton Road, Balham, in the County of
Surrey, Electrical Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
My invention relates to improvements in electric meters of the kind or class
which depend for their action on the difference in the rate of two clocks. This
difference is caused by the current to be measured and is proportional to that
current. Such meters are described for example in the Specifications of British
Letters Patent No. 6770 A.D. 1884 and No. 8856 A.D. 1887. The accuracy of
such instruments depends to a large extent upon the synchronism of the two clocks
when no current is flowing, since any deviation from synchronism, unless such
deviation is known and allowed for, will cause the instrument to read incorrectly.
According to my invention I secure a magnet to each pendulum, balance wheel,
or other suitable reciprocating part of the clockwork. Said magnet may be either
a permanent magnet or an electro-magnet or solenoid, or I may use a piece of
magnetic material on one of the parts and a magnet or the like on the other of the
parts.
The solenoid or electro-magnet may be energized by the current flowing in a
shunt circuit if thought desirable. The magnets are secured on the reciprocating
parts in such positions that the magnet on one pendulum or balance acts on the
magnet or the like on the other pendulum or balance either by attraction or
repulsion, the effect of this arrangement being to make the pendulums or balances
act upon one another as though they were connected together by a very flexible
cord. That is to say, the magnets so operate in the event of tendency to non-
synchronism as to retard the pendulum, balance wheel or the like which tends to

page_text: swing fastest, and to accelerate the other one. In other words the change of
attraction and repulsion is maintained a minimum.
In order that my invention may be more readily understood I will now proceed
to explain the same with reference to the accompanying drawings in which
Figure is a front view of a meter the pendulums of which are fitted with
magnets according to my invention.
Figure 2 is a section on line a, a Figure 1.
Figure 3 is a view shewing the application of my invention to reciprocating
balance wheels instead of pendulums.
Like letters denote similar parts in all the figures.
Referring now to Figures 1 and 2. A, A' are the rods of the two pendulums,
B, B' are magnets secured in any suitable manner to said rods. The poles of the
magnets are marked N, S, N₁, S' respectively and for the purposes of my invention
either unlike poles of the two magnets may be adjacent as shewn in the figures for
example or the reverse may be the case. The magnets may be permanent magnets
or electro-magnets or solenoids or one of said magnets may be replaced by a piece
of magnetic material.
In Figure 3 I shew two reciprocating balance wheels A², A³ each having a
magnet or the like B2, B3 secured thereon. The same remarks as to the position
of the poles and type of magnet apply in this case as in the case of the pendulums
above described.
I can apply magnets or the like to any pair of reciprocating parts of the two
mechanisms or clocks which together form the meter although I have only shewn
such application to pendulums or balance wheels. Such maguets may be secured
to said parts in any suitable position.
I sometimes make the whole or part of either or both of the reciprocating parts
a magnet or of magnetic material, for instance the pendulum rods or pendulum bobs
may be magnets in which case said parts need not be furnished with separate
magnets.
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 of the kind mentioned, magnets or their equivalents
attached to or forming part of two reciprocating parts, for the purpose specified.
2. An electric meter of the kind specified, in which synchronism is maintained
between the trains of the meter by means of magnets or their equivalents arranged
and operating substantially as described with reference to the drawings, for the
purpose specified.
Dated the 2nd day at
Hated the 3rd der at Lan
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.