An Improved Electric Meter.
Year: 1890

page_text: Date of Application, 29th Oct., 1890-Accepted, 29th Nov., 1890
COMPLETE SPECIFICATION.
An Improved Electric Meter.
I, HERBERT WOODVILLE MILLER. of No. 2 York Mansions, Earls Court, in the
County of Middlesex, Electrical Engineer, d 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 :-
My invention has for its object a construction of electric meter wherein a single
clockwork mechanism is combined with differential gear actuating registering
mechanism, part of which gear is subject to the influence of the electric current
to be measured in such manner that when there is no supply of electric current
passing through the instrument the part of the differential gear which is influenced
by the current moves without imparting any motion to another part of the
differential gear connected to the registering mechanism, while, on the passage of
the current, the motion of the first named part of the differential gear is more or
less retarded thereby, and is thus made to impart motion through the other part
to the registering mechanism the extent of such motion being in proportion to the
strength of the current passing.
The clockwork may be of any suitable known kind, driven either by weight,
spring power, or electricity, and it may be arranged so as to be either wound up by
hand or automatically by electrical means.
I will proceed to describe by way of example the arrangement for carrying out
my said invention shewn at Figs. 1 to 3 of the accompanying drawings in which
Fig. 1 shews a back view of the instrument.
Fig. 2 a plan, and
Fig. 3 a detached detail.
The clockwork G, which is of ordinary construction, drives the wheel A of the
differential gear A B C, continuously; the two bevil planet wheels B B' which gear
both with A and with the wheel C consequently also revolve continuously, both on
their own axes, and round the axis H which passes through the hollow independent
axes of A and C, and if their free rotation is not impeded, they will roll upon C while
this remains stationary.
If however the wheels B be subject to a retarding action while A continues to be
driven at a uniform speed they will then cause the wheel C to revolve in the contrary
direction to A at a speed which will be proportionate to the retarding action to which
the wheels B are subjected and will impart this motion to the first motion shaft of
the counter X. For producing the said retarding action by means of the electric
current to be measured, the following arrangement is employed.
On the shatt H carrying the wheels B B are fixed one or more permanent
magnets E E' which consequently revolve continuously with the wheels B in front of
one or more coils of wire D D through which the current to be measured passes.
When an electric current is passed through these coils they exercise an attraction
on the magnets E E' and thereby retard their rotation and consequently also that
of the wheels B B', so that, the current to be measured, or a part thereof, being
passed through the coils D, the retarding effect, and consequently the movement of
wheel and counter X will be proportional to the strength of the current.
In place of the permanent magnets E E' electro magnets or solenoids may be used
as shewn at Fig. 5 through which also the current to he measured, or a portion
thereof, is passed, these parts being either put wholly in circuit with the main leads,
or in a shunt circuit therefrom; or one or more of either the revolving coils E E
or the stationary coils D may be partly put in the main circuit and the other coils
be connected as a shunt across the main leads.
Or again, in place of permanent magnets, electro magnets or solenoids, may be used

page_text: as soft iron disc E as at Fig. 6, which in being polarised as it revolves opposite the
coil D will also have its rotation retarded. Or a copper dise E' may be employed
situated between two solenoids or electro magnets D D as at Fig. 7, so that the lines
of force passing from the magnets through the copper disc as it rotates will also tend
to retard its motion.
It will also be evident that other forms of differential gear may be used, such as
that shewn at Fig. 4, where the wheel A driven by the clockwork as before, is
connected by a tubular spindle to wheel A', and runs loose on the fixed spindle K.
B is a planet wheel gearing with A' and carried by disc E2 carrying the
magnets E El and running loose on K, E E being subject to the action of a coil as
before. B' is a second planet wheel on the same spindle as B and gearing with
wheel Con the hollow spindle of C also loose on K and which drives the counter
spindle X:
When the magnets E E¹ do not have their rotation retarded, A A' will cause B₁ to
revolve round C, without imparting motion to C, but when E E¹ E² are retarded by
the action of the current flowing through the coil, B₁ will drive CC round at a
speed proportionate to the retarding action.
An electro magnetic brake or stopping mechanism may be provided for stopping
the pendulum or balance wheel of the clock when no current is passing through the
meter.
For this purpose the arrangement shewn at Fig. 3 may be employed in which an
electro magnet F, through the coils of which the whole or part of the current to be
measured is made to pass, attracts an armature F¹ having a tail F, which is thereby
held out of the path of a stud L' on the balance wheel L, so that the clockwork is
then free to act, but when no current is passing, armature falls by its weight, and
the tail F projects into the path of the stud Land thus arrests the clockwork.
It will be seen that the above described invention has the advantage of decreased
cost of manufacture and of maintenance and repairs as compared with existing
electric meters of a similar kind, such as the Aron meter in which there are two
independent clocks acting on differential gear; or the Oulton-Edmondson meter in
which there are also two clocks driven by the same spring.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, declare that what I
claim is
An electric meter wherein a differential mechanism, one part of which is driven by
ordinary clockwork while another part is connected with a counter or registering
mechanism, is subject to the retarding influence of one or more electro-magnets,
solenoids, or coils, through which the current to be measured, or a portion thereof, is
made to pass, substantially as herein. described.
Dated this 29th day of October 1800.
ABEL & IMRAY,
Agents for the Applicant.