Improvements in Electric Meters.
Year: 1891

page_text: Date of Application, 28th Oct., 1891
Complete Specification Left, 28th July, 1892-Accepted, 10th Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in Electric Meters.
We, HAYDN THIES HARRISON of 29 Dorchester Place, Blandford Square,
London N.W. Electrical Engineer, and GEORGE WILLIAM BUDD of 127 Long
Acre, London W.C. Engineer, do hereby declare the nature of this invention to
be as follows:-
In an electrical energy or quantity meter according to this invention the
electrical energy to be measured is caused to increase the amplitude (i.e. the length
of swing or oscillation) of a pendulum or equivalent oscillating device (for example
a balance wheel) the number of swings or oscillations whereof per minute is kept
constant, and the increase of amplitude is registered by any suitable registering
mechanism. Measuring apparatus to operate on this principle may be constructed
and arranged in various forms. In one arrangement conveniently the pendulum
can be kept swinging by a shunt current or clock mechanism at a constant number
of beats per hour and normally at a constant amplitude but this amplitude is
increased by the electrical energy or quantity to be measured whilst the number of
beats remains constant. For this purpose the pendulum is kept of a given length
care being taken that the force exerted by gravity on the pendulum shall
remain unaffected and that only the force which keeps the pendulum in motion
shall be increased.
In one arrangement of apparatus according to this invention a pendulum has
fixed to its lower extremity two fine wire coils, the axis. of which is approximately
an arc of a circle struck from the axis of oscillation of the pendulum. A suitable
commutator or contact breaker affixed to the pendulum causes a current passing
through the coil to be periodically interrupted or reversed. Two coils are fixed,
one on either side of the pendulum in such a way that the coils on the pendulum
can swing freely into and more than half way through each.
On the outside of each of these two coils are wound a few turns of thick wire
through which the current to be metered is made to pass in such a way as to
increase the magnetic field caused by the shunt current passing through the fine
wire coils within them.
The mechanism for imparting the increase of amplitude of the pendulum to the
registering gear, may consist of two pins one on either side of the pendulum,
mounted at such a distance apart, that the pendulum swinging at its normal
amplitude when no current to be metered is passing, will come up to but will not
move the pins. These two pins are so mounted as to be free to move in the same
plane as the pendulum and are in connection each with one of two pawls gearing
in a ratchet wheel in such a manner, that when either pin is moved it will partly
rotate the ratchet wheel in proportion to the movement of the pin. Thus this
ratchet wheel will be caused to impart to any suitable registering mechanism the
increase of amplitude of the pendulum which will be in proportion to the current
passing through the thick wire coils.
The meter when thus constructed will operate as follows:-
The shunt current entering into the fine wire coil affixed to the pendulum will
draw it into the magnetic field caused by the fine wire coil at one side of the
pendulum; the pendulum having arrived at a certain position the current will be
interrupted, the contact being broken, until the pendulum resumes its vertical
position, when the contact will be made again but in the opposite direction, drawing
the pendulum into the magnetic field caused by the fine wire coil at its opposite
side; thus the pendulum continues to swing at a constant speed with a constant
amplitude, exactly between the two pins of the registering gear, but without

page_text: moving either of them, and therefore without causing any registration of energy;
but directly current passing through. the thick wire coils increases the magnetic
field in the two fixed coils the amplitude of the pendulum will be increased thereby
causing the pendulum to move the two pins and thus registering the amount of
current passing.
Dated this 28th day of October 1891.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Electric Meters.
We, HAYDN THIES HARRISON of 29 Dorchester Place, Blandford Square,
London N.W. Electrical Engineer, and GEORGE WILLIAM BUDD of 127 Long
Acre, London W.C., Engineer, 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 an electrical energy or quantity meter according to this invention, the electrical
energy to be measured, is caused to increase the amplitude (i.e. the length of swing
or oscillation) of a pendulum or equivalent oscillating device, (for example a
balance wheel) the number of swings or oscillations whereof per minute is kept
constant, and the increase of amplitude is registered by any suitable registering
mechanism. Measuring apparatus to operate on this principle may be constructed
and arranged in various forms.
The pendulum can be kept swinging by a shunt current, or by clock mechanism
in a manner well understood, at a constant number of beats per hour, and normally
at a constant amplitude but which amplitude is according to this invention increased
by the electrical energy or quantity to be measured whilst the number of beats
remains constant. For this purpose the pendulum is kept of a given length, care
being taken that the force exerted by gravity on the pendulum shall remain
unaffected, and that only the electrical force which keeps the pendulum in motion
shall be increased.
In the accompanying drawings,
Fig. 1 illustrates diagrammatically one arrangement of electric meter constructed
according to this invention.
Figs. 2, 3 and 4 are similar views illustrating modified constructions.
Figs. 5 and 6 are detail views.
In the arrangement shown in Fig. 1 of the drawings, 1 is a pendulum to the
lower extremity of which are fixed two fine wire coils, 2, 2" the axes of which form
approximately an arc of a circle struck from the axis of oscillation 3 of the
pendulum. A suitable commutator or contact make and break device operated
by the pendulum causes a current to pass through each of these coils 2, 2*
alternately.
For this purpose one end of the coil 2 is connected by a conductor 4 to a
contact piece 5, and one end of the coil 2ª is connected by a conductor 4* with
another similar contact piece 5º, the two contact pieces 5, 5 being insulated from
each other by insulating material 5° and carried by a bar 6 pivoted to the
pendulum as more clearly shown in Figs. 5 and 6. The other ends of the two
coils are connected at 7 to the pendulum which is in metallic connection by a
conductor 8 with one of the terminals 9 of the instrument. 10 is a pivoted metal
bar connected to a terminal 11 that is placed in connection with the return
conductor when the meter is in use. This bar is formed with a projecting
flange 10, the under surface of which on the pendulum swinging in the direction
of the arrow, slides over the contact piece 5 and places the coil 2 in a shunt circuit
between the electric mains. On the pendulum swinging in the reverse direction,

page_text: the contact piece 5ª will slide over the top of the said flange thereby breaking
the circuit of the coil 2 and placing the coil 2 in a shunt circuit.
6 is a stop
carried by the pendulum and serving to limit the downward movement of the bar 6.
10 is a spring that serves to press the flange 10" in contact with the contact
pieces 5, 5 alternately.
On each side of the pendulum is a stationary coil 12 so arranged that the
coil 2 or 2 on the corresponding side of the pendulum, can swing freely into and
more than half way through it. These two coils 12 are in circuit with each other,
and are when the meter is in use, in a shunt across the electric mains between
which a constant electro motive force is normally maintained. On the outside
of each of these two coils 12 is wound another coil 13 consisting of a few turns of
thick wire through which the current to be metered is made to pass in such a way
as to increase the magnetic field caused by the shunt current flowing through the
fine wire coils 12 within them.
The mechanism for actuating the registering gear on the increase of amplitude
of the pendulum, comprises in the example shown, a pin 14 so arranged at one side
of the pendulum that when the pendulum is swinging at its normal amplitude due
to a shunt current flowing through the fine wire coils 12 and alternately through
the coils 2 and 2ª, and no current to be metered is passing through the coils 13,
the pendulum will come up to but will not move it. This pin is fixed to a lever 15
that is pivoted at 16. This lever is normally held against a fixed pin 17 by a
spring 18 and carries a spring pawl 19 that is in gear with a ratchet wheel 20,
the arrangement being such that when the pendulum swings beyond its normal
amplitude, it will act against and move the said pin in one direction and move the
pawl 19 over a corresponding number of teeth, and upon the pendulum swinging
in the opposite direction, the lever 15 will be moved in the reverse direction by the
spring 18 and will thereby cause the pawl to partly rotate the ratchet wheel. By
this means the ratchet wheel will be caused to operate any suitable registering or
counting mechanism 21 which will consequently register the increase of amplitude
of the pendulum which will be in proportion to the current passing through the
thick wire coils 13.
The meter when thus constructed will operate as follows:-
On a shunt current flowing through one or other of the fine wire coils 2 or 2*
such coil will be drawn into the magnetic field caused by the fine wire coil 12 on
the same side of the pendulum, thereby causing the pendulum to move to one side.
The pendulum having arrived at a certain position, the contact piece 5 or 5* as the
case may be, will move out of contact with the pivoted bar 10 and the circuit of
the said shunt coil will be broken. The pendulum will then swing in the reverse
direction and when it resumes its vertical position or nearly so, the circuit of the
other coil 2 or 2 will be completed by the contact piece 5 or 5 and pivoted bar 6
and such coil will be drawn into the magnetic field of the stationary fine wire
coil 12 at its opposite side and thus the pendulum will continue to swing at a
constant speed with a constant amplitude and up to the pin 14 of the registering
gear but without moving this pin, and therefore without operating the registering
mechanism; but directly the current to be metered is caused to flow through the
thick wire or series coils 13 the magnetic field due to the two stationary coils 12
will be increased, whereby the amplitude of the pendulum will be increased, thereby
causing the pendulum to move the pin 14 and thus operate the registering
mechanism which will thus register the amount of current passing.
In the modified arrangement illustrated in Fig. 2, the pendulum is only provided
with one shunt coil 2 which is made hollow and arranged to swing over the
stationary concentric shunt and series coils 12 and 13 respectively. One pair only
of these coils is used in this case and they are arranged centrally as shown being
carried by a fixed bar 12º. The contact make and break device shown in this
arrangement comprises a stationary adjustable contact piece 22 and a movable
contact piece 23 carried by a spring arm 24 fixed at 25 and provided with a
projection 26. This projection is arranged to enter a recess 27 in the boss 28 of a

page_text: .
lever 29 pivoted at 30 to the meter case and provided with two adjustable stops 31
between which the pendulum vibrates. The arrangement is such that when the
pendulum arrives in a suitable position; depending upon the adjustment of the
stops 31 the projection 26 will enter the recess 27 in the boss 28 and allow
the contact piece 23 to bear against the contact piece 22 and complete the circuit
of the movable shunt coil 2 so that the repulsion set up between this coil and the
fixed shunt coil 12 will cause the pendulum to swing to one side sufficiently to
cause it to come into contact with one or other of the stops 31 and rock the
lever 29 on its pivot 30. This will cause the projection 26 to leave the recess and
slide on the circumference of the boss 28 and move the contact piece 23 away
from the contact piece 22 thereby breaking the circuit of the coil 2. The pendulum
will then swing in the reverse direction and when it resumes the corresponding
position on the other side the circuit of the coil will be again completed and the
oil 2 will be again repelled but in the opposite direction to its previous repulsion
owing to the coil being caused to pass its mid position by reason of its momentum.
If no current be flowing through the series coil 13, as when no electric lamps,
motors or other electric transmitting devices are in use, the amplitude of vibration
of the pendulum will as before, be such that it will move up to, but will not
operate, the pin 14 of the registering mechanism, but when a current is caused to
flow through the series coil by reason of the electric lamp or other device being
switched into circuit, the amplitude of vibration of the pendulum will be increased
and registered by the counter 21.
In the arrangement shown in Fig. 3 the fixed shunt coil or coils is or are
replaced by two iron cores 32 one at each side of the movable shunt coil 2, and
upon which the series coils 13 are wound as shown. In this case when no current
is passing through the series coils, the pendulum is caused to vibrate at a constant
rate by the attraction set up between each iron core in turn and the movable
shunt coil 2, the circuit of which is made and broken by a contact make and break
device like that shown in Fig. 2. In other respects the operation of this arrange-
ment is similar to that hereinbefore described with reference to Fig. 2.
In the arrangement shown in Fig. 4, the oscillating part of the meter is in the
form of a circular bar or part wheel 1° arranged to work somewhat after the
manner of a balance wheel, its ends being provided with shunt coils 2, 2ª that are
drawn alternately into the concentrically arranged fixed shunt and series coils 12
and 13. This part wheel which constitutes an equivalent of a pendulum is con-
nected at its centre to one end of a coiled spring 15, the other end of which is fixed
to the base of the instrument. The circuits of the shunt coils 2, 2ª are made and
broken in turn by a contact make and break device similar to that shown in
Figs. 2 and 3, and the counting mechanism 21 is operated as before by a lever 15
which is actuated by a pin or projection 33 on the underside of the part wheel 1°.
At starting, that coil 2 or 2ª which happens to be nearest the fixed fine wire
coil 12 will be attracted and thereby partly rotate the part wheel 1ª in one
direction and break the circuit of the coils 2, 2º. When the part wheel, during
its partial rotation in the reverse direction under the action of the spring 1', arrives
at or near its central position, the circuit of the coils 2, 2ª will be again completed
and the coil 2ª or 2 that is approaching the coils 12 and 13 will be drawn into
such coils until the circuit of the said coils 2, 2ª is again broken.
The pin or projection 33 may be replaced by a suitable shaped snail or cam that
bears at all times against the lever 15, thereby avoiding shock. The coils 2, 2*
may be replaced by pieces of soft iron. In this case the circuit of the shunt
coil 12 must be arranged to be made and broken by the contact making and
⚫breaking device.
In this way the part wheel 1ª will be caused to oscillate at a constant rate, its
-amplitude varying as before with the current flowing through the series coil 13.
Each of the meters described may be provided with a suitable device to facilitate
its starting. A convenient device for this purpose is shown in Fig. 2. It comprises
a light tongue or fan 34 of metal, for example aluminium, pivoted to and eléctrically

page_text: connected with the shunt coil 2 and adapted to bear against a fixed contact piece 35
when the pendulum is stationary, and to then short circuit a resistance 36 that
is arranged in circuit between the shunt coil 2 and the terminal 9 to which the
contact 35 is also connected by a conductor 35. By this means assuming the
meter to be at rest and a difference of potential to be set up between the terminals 9
and 11, a larger current than the normal will flow through the shunt coil 2 and
cause it to be repelled to one side of the shunt coil 12 and thereby set the pendulum
swinging. The tongue 34 during the swinging of the pendulum will assume an
inclined position relatively to the coil 2 due to the resistance of the air when
swinging so that it will not again make connection with the contact piece 35 until
the pendulum again stops, and the circuit of the coil 2 will be completed through
the resistance 36, so that only sufficient current will then flow through it to cause
the pendulum to vibrate with the normal amplitude. The pendulum or its equivalent
may be caused to vibrate at a constant rate by clock mechanism in a manner that
will be readily understood.
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:-
1. An electric meter in which the electrical energy or current to be measured
is caused to increase or vary the amplitude of a pendulum or equivalent oscillating
device the rate of oscillation of which is kept constant, the increase of amplitude
being registered by suitable registering mechanism substantially as described.
2. In an electric meter the combination with a pendulum or equivalent oscillating
device having a constant rate of vibration and carrying a coil or coils through
which an electric current is caused to flow intermittently by a make and break
device, of a stationary coil or coils through which the electricity to be measured is
caused to flow so as to increase the amplitude of the pendulum or equivalent
oscillating device, and registering mechanism adapted to be operated by the said
pendulum or equivalent device when the amplitude thereof is increased and to
register the increase of such amplitude substantially as herein before described.
3. Electric meters constructed arranged and operating substantially as herein-
before described with reference respectively to and shown in Figs. 1, 5 and 6; in
Fig. 2; in Fig. 3; and in Fig. 4 of the drawings annexed whether with or without
a starting device as set forth.
Dated this 20th day of Jul 1809
HAYDN THIES HARRISON.
W. Lloyd Wise,
Per F. J Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.