Improvements in Electricity Meters.
Year: 1889

page_text: Date of Application, 5th Dec., 1889
Complete Specification Left, 5th Sept., 1890-Accepted, 25th Oct., 1890
PROVISIONAL SPECIFICATON.
Improvements in Electricity Meters.
We WILLIAM HARDING SCOTT Electrical Engineer of Gothic Works King Street
Norwich & LAURENCE PARIS & SCOTT LTD. also of Gothic Works Electrical
Engineers do hereby declare the nature of this invention to be as follows:-
This invention consists of modifications & improvements to the apparatus
described in our application for Letters Patent dated 1888, No. 16623.
This apparatus consists of two parts first, a timing arrangement which may be used
itself to measure electricity; & secondly, an indicating & integrating apparatus which
periodically registers the current & integrates the current flowing. The timing
arrangements which can also be used as a measuring arrangement, consists of--A rod
tube or strip of metal such as zinc or brass which has a high expansibility, this is
supported by a ridged support or frame of the same metal or metal of similar expansi-
bility the rod tube or strip being fixed at one end to the frame & at the other end to
a lever or system of levers so that any: lengthening or shortening of it will move a
pointer or finger.
The rod tube or strip being of the same metal as its support & any variation from
this or in the quality of the rod tube or strip from its support must be compensated
for by pieces of other metal so that both the rod tube or strip & its support shall if
evenly heated expand exactly alike, but if the rod tube or strip be heated separately it
will lengthen & the lengthening will be multiplied by the lever or system of levers so
as to move the pointer a considerable distance.
In this apparatus, the lengthening is effected by the current either flowing in the
rod tube or strip, or round it, so that according to the strength of the current flowing
it will heat up the rod strip or tube & move the pointer.
When this apparatus is employed as a timing arrangement a current is made to flow
in or round the rod tube or strip making the pointer by means of a rocking switch
break the circuit as soon as the heating reaches a certain point & complete the circuit
again as soon as the rod tube or strip is cooled down a certain amount. We prefer
that the rod tube or strip which is heated by the current should be arranged in tension
by the system of levers so that the expansion shall let down & its contraction lift a
weight or spring. This timing arrangement may be used in connection with the
indicating & integrating arrangement described in our Patent No. 16623 (1888)
beforementioned in which the high resistance shunt current thus periodically made &
broken is made to act upon & be acted upon by a series current so that the indications
are proportional to the currents in these. circuits, or to one of them. By the present
invention we may use for the indicating apparatus flat coils of wire or conductor of
which we prefer to make the coils of fine wire moveable & the coils of the thick
conductor fixed. The fine wire coil or coils may be fixed upon a rod the ends of
which are suspended on metal or otherwise strips, so that the coil is free to move in
the direction of the longitudinal axis of the supporting rod.
The thick conductor coil or coils are fixed adjacent to the suspended fine wire coils
so that if the current flows through both the fixed & the moveable coil or coils the
latter is or are moved in proportion to the current flowing in these coils.
The movement is by means of a rack & pinion or its equivalent communicated to a
small spindle on which is an arm carrying a lever or pawl which can catch in & carry
round a large indicating wheel geared to the indicating train. On or round the small
spindle is a coil of fine wire in series with the shunt coil aforementioned this when the.
shunt circuit is completed operates the lever or pawl so as to lift it off the indicating
wheel & the arm & pawl is carried round without the indicating wheel a distance in
proportion to the current in the coils. When the shunt circuit is broken the magnet

page_text: on or about the spindle lets down the pawl on to the indicating wheel which is carried
round an amount in proportion to the movement of the lever on the small spindle due
to the currents. The magnet which works the pawl may be fixed to the spindle &
revolve with it, or it may be stationary & so arranged that it acts upon the pawl the
same whatever the position may be of the lever on the spindle to which the pawl is
attached. It is obvious that the magnet on or about the small spindle may when the
shunt circuit is completed either lift off or put on the catch to the indicating wheel.
Or byanother arrangement, a small fixedelectromagnet inthe shuntcircuit
so that by means of a long arm or lever it may put the pawl in gear against a spring
or its own weight with the indicating wheel when the shunt current is broken & be
lifted out of the way when the shunt circuit is completed the pawl being then cleared
from the indicating wheel by the aforementioned spring or its own weight the lever
can then take up a position according to the current flowing.
arranged
In continuous currents we prefer to have for the suspended coil or coils a shunt coil
wound on a long iron core extended very much beyond one or both ends of the coil,
outside the coil is an iron tube or its equivalent which extends out as far as the core
at one or both ends, so that when the shunt circuit is completed there is a very strong
magnetic field between the prolongations of the iron core & the outside iron tube, in
this space between the iron core & outside tube the series coils are placed so that when
a current flows in them & the shunt circuit is completed the suspended coil is moved
as aforementioned. This suspended coil may be of considerable weight & it may be
weighted to regulate the amount of its movement.
For alternating currents we may use one or preferedly several flat coils of fine wire
on a spindle suspended by its ends as before mentioned with the flat coils of thick
conductor for the series current fixed at either side of & between the suspended coils.
In order to take the lever which works the indicating wheel always back to zero, we
may use a lever worked by the timing arrangement which will always take the afore-
said lever to a certain fixed zero before the shunt circuit is completed & will be lifted
out of the way by the working of the timing arrangement when the shunt circuit is
completed.
Dated thi T
2
COMPLETE SPECIFICATION.
Improvements in Electricity Meters.
We, WILLIAM HARDING SCOTT of Gothic Works King Street Norwich in the
County of Norfolk Electrical Engineer, and LAURENCE PARIS AND SCOTT LIMITED of
Gothic Works aforesaid 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 consists of modifications and improvements in apparatus such as is
described in Letters Patent dated 15th November 1888 No. 16623. We will describe
the present invention with reference to the accompanying drawings.
The apparatus consists of two parts; first, a timing arrangement, which may be
used itself to measure electricity; and secondly, an indicating apparatus which
periodically registers and integrates the current flowing.
timing, or for both timing and measuring, is shewn in side elevation, partly in section,
The arrangement for
in Figure 1, and in plan in Figure 2. B is a rod, tube, or strip, of metal which has
a high expansibility under the action of heat (such for example as zinc or brass).
The said rod, tube, or strip, B, is supported, at one end, by a rigid support, or
frame, A, of the same kind of metal as the rod B or metal of the same or practically
the same expansibility or if it be not of the same metal or metal of the same

page_text: expansibility difference in expansibility may be compensated for by pieces of other
metal combined therewith.
The other end of the rod B is fixed by means of the strip of metal C to one end
of a lever D (or system of levers) so that any lengthening or shortening of the said
rod B will move a pointer or finger E attached to the lever D. The rod B being of
the same degree of expansibility as its support A when they are both evenly heated
by change of atmospheric temperature for instance they will expand together and so
the lever D which has its fulcrum on the support A will not be moved but if the rod B
be heated separately it alone will lengthen and its lengthening will move the outer
end of the pointer E a considerable distance. The heating of the rod B is effected
either by the current flowing in it or around it as shewn in the drawing by means of
the coil G so that according to the strength of the current flowing and the con-
sequent degree of heating of the rod B the said rod will expand and so move the
pointer or finger E to a corresponding extent.
We prefer that the rod B is so arranged that it will be kept in tension which we
can accomplish by means of the spring H secured at one end to the case A and at
the other end to the lever D.
The knife-edge fulcrum F of the lever D we arrange close to the strip C so that a
very small movement of the rod B will cause a large movement of the pointer E
thus only necessitating a single lever.
The apparatus as above described may be used as a measuring arrangement to
measure the current flowing.
When this apparatus is employed as a timing arrangement the pointer is arranged
to break contact by means of the rocking switch when the heating of the rod B
reaches a certain point, and complete the circuit again when the rod B cools down to
a certain point. This may be done as follows:- The end of the finger E bears on
the tail piece of the tumbling bar J and as the expansion of the rod B raises the
finger E the fork e moves over the tumbler J which, by means of the projection k,
carries over with it the rod K and so breaks contact at M. When the rod B cools down
the fork e acts on tumbler J which falls back to its original position and the other
projection moves over the rod K and contact is again made at M.
This timing arrangement may be used in connection with the indicating and
integrating arrangement described in the Specification of our before mentioned
Patent No. 16623 of 1888 in which the shunt current thus periodically made and
broken is made to act upon, and be acted upon, by a series current so that the
indications are proportional to the current to be measured.
By the present invention we may use for the indicating apparatus means illustrated
by Figures 3 and 4 where a fine coil (or coils) of wire or conductor N is fixed
upon a rod P (Figures 4 and 5) the ends of which rod are suspended by flexible
metal strips or otherwise so that the said fine wire coil and its rod are free to move
in the direction of their longitudinal axis practically without friction though of
considerable weight.
We fix adjacent to the fine wire coil N series or thick wire coils Q carried by
stationary supports so that when currents flow through both the fixed and moveable
coils Q and N the moveable coil is moved to an extent in proportion to the currents
flowing in the coils. This movement is (by means of the chain and wheel q or by a
rack and pinion or by equivalent means) communicated to a spindle s (Figure 3) on
which is fixed an arm 2 carrying a lever or pawl t which engages with ratchet teeth
on a wheel or disc 2 geared to the indicating train (not shewn).
We arrange fine wire magnet 3 in series with the shunt coil N which magnet s³,
when the shunt circuit is completed, attracts the armature t³ and operates the lever or
pawl attached thereto so as to lift it clear of the teeth and then the pawl t is carried
round by the arm a distance in accordance with the relative strengths of the
currents in the fixed and moveable coils. When the shunt circuit is broken by the
timing apparatus the pawl t returns into engagement with the teeth of the wheel t²
and is returned to its normal position by action of the spring n (see Figure 4) or if
the spring be dispensed with then by the weight of the rod P and its attachments

page_text: s or it
thus moving the wheel & round, and with it the train of indicating wheels, to an
extent corresponding to the previous extent of movement due to the strength of
current. The magnet may be either fixed to and revolve with the spindle
may be stationary and so arranged that it acts upon the pawl whatever the position of
the arms to which the pawl t is attached or instead of the magnet s³ lifting the pawl
off the wheel t² it can be arranged to put it on.
We may provide a lever wo worked from the pointer E of the timing apparatus
through the flexible connection to insure that when the shunt circuit is broken the
arms shall be brought up against the stop by the lever w acting on a projection w³
on the arms. When the shunt circuit is completed the lever we is lifted clear of the
projection so as to allow the arm 2 to turn freely. Should the current being
measured be so strong as to move the lever before the timing apparatus has moved
it away it will not interfere with the result on account of the flexibility of the
connection w³.
We prefer, for use with continuous currents, to have for the suspended coil a fine
wire shunt coil N, wound on a long iron core P extended beyond one or preferably
both ends of the coil N as is shewn in Figure 4. Outside the coil N is an iron
tube P2 which extends as far as the core I at one or both ends so that when the
shunt circuit is completed there is a strong magnetic field between the prolongations
of the iron core P and the outside iron tube P2. In this field the series coils Q are
placed so that when a current passes through them and the shunt circuit is completed
the coil N is moved as before mentioned.
We do not confine ourselves to the exact arrangement of the suspended double
electro magnet described. We prefer to make it double in order that the effects of
the current in the two fixed coils alone on the iron of the suspended electro-magnet
may neutralize one another so that there is no movement of the suspended electro-
magnet except when the shunt current is completed.
We may obtain the same result by using two shunt coils one at each end of the
suspended electro-magnet and one fixed coil in the magnetic field between them the
ends of the coil being in this case magnetically closed up.
For alternating currents we use preferably several coils of fine wire N on the bar P
of non-magnetic material suspended at its ends as before mentioned with the series
coils Q of thick wire between them as shewn in Figure 5.
We prefer to make the suspended bar P Figures 4 or 5 with its attachments of
considerable weight and it may be further weighted to regulate the amount of its
movements.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is ;-
First. A measuring apparatus (which may also be used as part of a timing arrange-
ment) consisting of a rod tube or strip kept in tension and supported as described so
that a current flowing in or around the rod tube or strip will by its heating effect give
amplified movement to a pointer E to indicate the strength of current substantially in
the manner herein before described with reference to Figures. and 2.
Second. In electricity meters a coil (or coils) N suspended on a rod as described
with stationary series coils Q placed near them so that by the periodical making of the
shunt circuit the suspended coil (or coils) will be moved to an extent in proportion
to the strength of current and the movement thereof will effect the operation of a
registering apparatus substantially as herein before described.
Third. A suspended electro magnet so arranged that a magnet field or magnetic
fields is or are produced when the shunt current flows in which field or fields is or
are arranged the series coil or coils as described so that the series current in this coil
or these coils shall have practically no effect to move the suspended electro magnet
except when the shunt current is flowing substantially as herein before described.
Fourth. In meters for measuring electric current an iron core P prolonged beyond
the fine wire coil or coils and the external iron tube P3 which is also prolonged so

page_text: that in the space between there shall be a strong magnetic field in which the series
coil or coils is or are situated substantially as shewn in Figure 4 whether the coils be
arranged as there shewn or as shewn in Figure 5.
Fifth. In electricity meters of the kind described a lever w engaging with a stop w
and connected with the expansion device for ensuring the arm being returned to
zero on the shunt circuit being broken by the timing apparatus substantially as
herein before described and shewn in Figure 3.
Sixth. The arrangement and combination of parts as a whole constituting an
electricity meter substantially as hereinbefore described and illustrated by the
accompanying drawings.
Seventh. An electrically operated pawl & Figure 3 which by the action of the shunt
current is lifted clear off the integrating disc during one swing of the operated arm
and falls on to the integrating disc and carries it round during the other swing
substantially as herein before described.
FEL
1
1
1000
J. H. JOHNSON & Co.,
Agents.