Improvements in Electricity Meters.
Year: 1897

page_text: I, GEORGE HOOKHAм, of 7 and 8 New Bartholomew Street, Birmingham, Manu-
facturer, do hereby declare the nature of this invention to be as follows:-
In motor-meters in which the driving force depends upon the interaction between
shunt coils or a shunt magnet and series coils or a series magnet it is often
advantageous to give a tendency to start by super-adding an arrangement whereby
a small driving-force is supplied even when no current is passing through the
series coils. This is accompanied by the danger that the meter may actually
start under these conditions.
To remedy this I apply a magnetic pole close to some part of the rotating
armature and on the armature itself along the line passing close to this magnetic
pole I fix a piece of fine iron wire or its equivalent extending along about one
fourth of the circle described by a point on the armature at this part; the action
then is as follows. When the leading end of the wire approaches this magnetic
pole the motion is accelerated by the attraction of the pole for the piece of wire.
But before the other end of the wire reaches the pole this acceleration is lost and
the motion slows down to the normal speed of the armature. When this end of
the wire reaches the pole the motion of the armature is quietly arrested: and the
forces are so adjusted that the armature is safely held at rest till the smallest
current with which the meter is intended to run continuously, passes through the
series coils; when it starts and begins to register.
Improvements in Electricity Meters.
I, GEORGE HOOKнAM, of 7 and 8 New Bartholomew Street, Birmingham, Manu-
facturer, 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:-
In motor meters in which the driving force depends upon the interaction between
shunt coils or a shunt magnet and series coils or a series magnet it is often
advantageous to give a tendency to start by superadding an arrangement whereby
a small driving force is supplied, even when no current is passing through the
series coils. This is accompanied by the danger that the meter may actually
start under these conditions.

page_text: My invention consists in a device which remedies this defect.
Referring to the accompanying sheet of drawings
Figure 1 is a plan, and
Figure 2 an elevation of part of an electricity meter showing the application of
my invention to the disc.
I apply a permanent magnet A close to some part of the rotating disc arma-
ture B, and on the armature B itself along the line passing close to the adjustable
magnetic pole E carried in the clamp D attached to the magnet A I fix a piece
of fine iron wire such as C Figure 1, or its equivalent, extending on an arc of about
one fourth of the circle described by a point on the said armature B.
The action then is as follows. When the leading end of the wire C ap-
proaches the adjustable magnetic pole piece E the motion of the disc is accelerated
by the attraction of the pole piece for the piece of wire, but before the other end
of the wire reaches the pole this aceleration is lost and the motion of the disc is
Blowed down to its normal speed, when this end of the wire C approaches the
adjustable pole piece, the motion of the armature is quickly arrested and the forces
are so adjusted that the armature B is safely held at rest till the smallest current
with which the meter is intended to run continuously passes through the series
coils when it starts and begins to register.
In previous patents granted to me I have described a method of stopping a
disc by means of a piece of iron placed on the disc; where this piece covers only
a small surface or the disc, I find that the eccleration produced in approaching
the pole piece sometimes carries the disc on. The novel point in this invention
consists in the use of an extended are of iron in any electricity meter.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is:-
In electricity meters the device for stopping with certainty consisting of an
iron arc or extended piece on the disc operating in conjunction with a magnet
substantially as described.
Dated this 11th day of December 1897.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.