Year: 1897

page_text: We, EVERSHED & VIGNOLES LTD., of Woodfield Works, Harrow Road, London,
W., Electrical Engineers, and SYDNEY EVERSHED, of the same address, Electrical
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to electric supply meters of the motor type described in
the Specification of a Patent granted to W. E. Ayrton and J. Perry numbered
2642 and dated 1882, and its objects are to increase the working range and reduce
the power wasted in such meters.
A meter made in accordance with our invention consists substantially of an
electric motor whose armature and field magnet coils carry, respectively, a current
proportional to the pressure and a current proportional to the whole current
supplied; so that the torque is proportional to the power supplied. The driving
torque being resisted by a device known as a Foucault current brake the speed of
the motor is proportional to the power supplied.
The armature is wound with fine wire and connected, through its commutator, as
a shunt on the main supply circuit, a sufficiently large resistance being connected
in series with the armature to reduce the pressure on the armature and commutator
to a safe amount. This resistance when wound non-inductively also adapts the
meter to alternate current work. Fixed coils surrounding the armature as closely
as possible and carrying the total current being supplied, serve as the field magnet
coils. The armature is attached to and rotates with a vertical axle to which a
cylinder or disc of aluminium, copper, or other good conductor of electricity is
also attached to provide the required opposing torque by means of stationary
magnets whose induction traverses the cylinder or disc and sets up eddy currents
therein.
The axle is pivotted in centres at the top and bottom. and in order to reduce the
pivot friction as much as possible the axle is, according to our invention, made of
iron or steel, and immediately above the upper pivot a permanent or electro-
magnet is fixed with its magnetic axis vertical and in line with the rotational axis
of the spindle. By observing suitable proportions of the various parts the upward
vertical attraction due to the magnetic induction passing from the magnet into the
axle may be made to support the weight of the armature axle and other parts
attached thereto, so that the bottom pivot is wholly or partially relieved of the
pressure due to their weight and the pivot friction is almost entirely eliminated.
An axle supported in this way may be and is herein called a magnetically
pivotted axle," and the end of the axle at which the magnetic attraction is exerted
may be and is herein called a "magnetic pivot."
Any want of symmetry in a magnetic pivot will tend to produce a turning
moment on the axle and in order that a magnetically pivotted axle may work
freely it is essential that it should be a true figure of revolution symmetrical about
the axis of rotation. The pole of the fixed magnet should be a similar figure if
possible, although this is not absolutely essential.

page_text: A turning moment may also be produced by want of uniformity of induction
density in the magnetic pivot and fixed pole and since this effect is due to
differences in the permeability of the iron or steel which cannot be altogether
eliminated a magnetic pivot and its supporting pole should be small in diameter so
that any unbalanced magnetic attractive force may have as small a turning moment
as possible.
For similar reasons it is desirable to so proportion a magnetic pivot and its pole
that the greater part of the induction between them shall be vertical and not radial
in direction; the radial induction if not absolutely symmetrically disposed round
the pivot will force the pivot towards that side on which the induction is greatest
and so cause a sideways pressure of the pivot on its bearing. Even the utmost
precision of mechanical workmanship is insufficient to entirely eliminate the effects
we have described, hence the importance of observing the essential conditions as
to the symmetry and dimensions of the magnetic pivot and its supporting pole
and as to the vertical direction of the magnetic induction.
In order to obtain the full advantage of the reduction in pivot friction due to
our magnetic pivot the armature commutator requires to be designed so as to avoid
sensible friction due to brush contact. According to our invention the commutator
may consist of a number of parallel bare wires arranged symmetrically round the
axle and parallel therewith. The wires are insulated from each other and from
the axle by means of two insulating collets or collars to which their ends are
attached, the whole arrangement being analogous to a lantern wheel such as is
used in clockwork. The diameter of a commutator made in this manner is only
limited by the size to which the axle which forms its centre can be reduced. We
provide a long and fine pivot at the lower end of the axle and build up our com-
mutator upon the upper part of this pivot leaving a sufficient length of pivot
projecting below to work in a jewel or other centre. A modified form of our
commutator may be made by laying a number of insulated wires around and upon
the axle or pivot and fixing them thereto by a suitable clamping ring at each end
of the commutator. When the wires have been thus fixed the insulating material
with which they are covered is scraped off from the peripheral surface of the
commutator.
The commutator brushes may each consist of two or three fine elastic wires and
in order to ensure good contact between the commutator and the brushes both the
commutator wires and the brush wires should be made of some durable and non-
oxidizable metal such as platinum or gold or an alloy in which either of those
metals is an ingredient.
The counting mechanism or train may be driven by means of a worm on the
armature spindle engaging in a worm wheel fixed to the first axle of the train.
In order to relieve the motor from the work required to drive the train we attach
a drum to one of the axles of the train and hang a weight therefrom by means of a
flexible cord coiled upon the drum. The weight is sufficiently heavy to just over-
come the friction of the train but the worm gearing does not permit the weight to
drive the armature spindle. With this arrangement the motor merely regulates
the speed of the train; acting in an analogous manner to the escapement of a
clock. The weight may be made of iron or steel and be acted upon by a fixed coil
as described in the Specification of Patent No. 7484, 1896.
In a modification of our invention there is no mechanical connection
between the motor and the train the latter being driven by a ratchet
wheel and pawl. The pawl is moved by an electro-magnet the circuit
of which is closed by a rotary contact maker fixed on the meter
armature spindle. The magnet circuit being closed once in each revolution
of the armature, the pawl drives the ratchet wheel forward one tooth for every
revolution. The extra friction due to the rotary contact may be eliminated by arrang-
ing the commutator brushes so that they serve to short circuit the electro-magnet
one or more times in every revolution of the armature. In another modifi-
cation for the same purpose one of the armature coils has the coil of a small electro-

page_text: magnet in series with it. The iron core of this electro-magnet is a cylinder fixed
to and concentric with the armature spindle. Immediately below or above the
lower or upper pole of the cylindric core a permanently magnetised pole in the form
of a ring round the spindle (but not attached thereto) is placed. The ring pole is
at one end of a balanced lever, and the reversal of polarity of the electro-magnet
which takes place twice in every revolution of the meter armature causes the lever
to alternately move up and down. This motion is utilized to work a pawl which
drives a ratchet wheel in connection with the train.
Dated this 9th day of Anvil 1907
EVERSHED & VIGNOLES, LIMITED.
E. B. VIGNOLES, Managing Director.
SYDNEY EVERSHED.
pements in Electric Meters.
We, EVERSHED & VIGNOLES LIMITED, of Woodfield Works, Harrow Road,
London, W., Electrical Engineers, and SYDNEY EVERSHED, of the same address,
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 ascertained
in and by the following statement:-
motor meter" is
This invention is applicable to electric supply meters of the motor type, and its
objects are to increase the working range and reduce the power wasted in the said
meters, by the reduction to an infinitesimal amount of the frictional resistances to
the rotation of the axle, and to drive the counting train independently of the
mechanical energy of the axle of the motor. We will describe our invention in
connection with a meter of the type described in the Specification of a Patent
granted to W. E. Ayrton & J. Perry numbered 2642 and dated 1882.
In this specification and in the following claims the phrase
used to signify any electric supply meter, in which an electric motor is employed to
measure directly or indirectly the quantity of electric energy or quantity of elec-
tricity supplied. And the phrase "motor meter of the Ayrton-Perry type" is used
to signify an electric supply meter of the motor type, having a rotary armature in
shunt to the work, and field coils in series with the work, and a brake whose resist-.
ance is proportional to the speed. The word "train" is used to signify any counting
mechanism such as is commonly used to indicate the quantities measured by a
meter.
A meter of the Ayrton-Perry type made in accordance with our invention
consists substantially of an electric motor whose armature and field magnet coils
carry respectively a current proportional to the pressure, and a current proportional
to the whole current supplied, so that the torque is proportional to the power
supplied. The driving torque being resisted by a device known as a Foucault
current brake, the speed of the motor is proportional to the power supplied.
The armature is wound with fine wire and connected through its commutator
as a shunt on the main supply circuit, a sufficiently large resistance being con-.
nected in series with the armature to reduce the electric pressure on the armature
and commutator to a safe amount. This resistance, when wound non-inductively,
also adapts the meter to alternate current work. Fixed coils, surrounding the
armature as closely as possible and carrying the total current, being supplied,
serve as the field magnet coils. The armature is attached to and rotates with a
vertical axle to which a cylinder or disc of aluminium, copper, or other good con-
ductor of electricity is also attached to provide the required opposing torque by

page_text: means of stationary magnets, whose induction traverses the cylinder or disc, and
sets up eddy currents therein.
The axle is pivotted in centres at the top and botom, and in order to reduce the
pivot friction as much as possible, the axle is, according to our invention, made
entirely, or as regards the upper part thereof, of iron or steel, and immediately
above the upper pivot a permanent or electro-magnet is fixed with its magnetic
axis vertical and in line with the rotational axis of the spindle. The magnetic
support is thus "unipolar" and will hereinafter be so referred to.
By observing suitable proportions of the various parts, the upward vertical
attraction due to the magnetic induction passing from the magnet into the axle
may be made not only to support the weight of the armature axle and other parts
attached thereto, so that the bottom pivot is wholly or partially relieved of the
pressure due to their weight, but the axle is also retained by the magnetic forces
in the axis of the magnetic induction, and is therefore retained in a vertical
position without lateral or rubbing bearings. The pivot friction is thus almost
entirely eliminated. An axle supported in this way may be and is herein called a
magnetically pivotted axle," and the end of the axle at which the magnetic
attraction is exerted may be and is herein called a magnetic pivot." That pole
of the fixed magnet which produces the said magnetic attraction may be and is
herein called the "supporting pole" and the arrangement of such supporting pole
and magnetic pivot constitutes our unipolar means of support.
It is obvious that any distribution of more than one pole about the axis of the
motor axle, or even a want of symmetry in a magnetic pivot, will tend to produce a
turning and retarding moment on the axle; and in order that a magnetically
pivotted axle may work freely it is therefore essential that it should be a true figure
of revolution symmetrical about the axis of rotation. The pole of the fixed magnet
should be a similar figure, if possible, although this is not absolutely essential.
A turning moment may also be produced by want of uniformity of induction
density in the magnetic pivot and fixed pole, and since this effect is due to
differences in the permeability of the iron or steel, which cannot be altogether
eliminated, a magnetic pivot and its supporting pole should be small in diameter
so that any unbalanced magnetic attractive force may have as small a turning
moment as possible.
For similar reasons it is desirable to so proportion a magnetic pivot and its pole,
that the greater part of the induction between them shall be vertical and not radial
in direction, the radial induction, if not absolutely symmetrically disposed round
the pivot will force the pivot towards that side on which the induction is greatest,
and may cause the axle to foul adjacent fixed parts of the meter. Even the utmost
precision of mechanical workmanship is insufficient to entirely eliminate the effects
we have described, hence the importance of observing the essential conditions as
to the symmetry and dimensions of the magnetic pivot and its supporting pole,
and as to the vertical direction and unipolar character of the supporting magnetic
induction.
It is obvious that this magnetically pivotted axle, though described by us in
connection with other parts of a specific type of motor meter, is applicable to any
type or form of motor meter in which a rotating axle is employed of which it is
important to reduce to an infinitesimal point the frictional resistance to rotation.
In order also to obtain the full advantage of the reduction in pivot friction due
to our magnetic pivot in our specific type of motor meter having an armature, the
armature commutator requires to be designed so as to avoid sensible friction due
to brush contact. According to our invention the commutator may consist of a
number of parallel bare wires arranged symmetrically round the axle and parallel
therewith. The wires are insulated from each other and from the axle by means
of one or two insulating collar or collars, to which their ends are attached, the
whole arrangement being analogous to a lantern wheel, such as is used in a clock
work. The diameter of a commutator made in this manner is only limited by the

page_text: size to which the axle which forms its centre can be reduced. We provide a long
and fine pivot at the lower end of the axle and build up our commutator upon the
upper part of this pivot, leaving a sufficient length of pivot projecting below to
work in a jewel or other centre. A modified form of our commutator may be made
by laying a number of insulated wires around and upon the axle or pivot, and
fixing. them thereto by a suitable clamping ring at each end of the commutator.
When the wires have been thus fixed, the insulating material with which they are
covered is scraped off from the peripheral surface of the commutator.
The commutator brushes may each consist of two or three fine elastic wires, and
in order to ensure good contact between the commutator and the brushes, both
the commutator wires and the brush wires should be made of some durable and
non-oxidizable metal, such as platinum or gold, or an alloy in which either of those
metals is an ingredient.
The counting mechanism or train may be driven by means of a worm on the
armature spindle engaging in a worm wheel fixed to the first axle of the train.
But in order to relieve the motor from the work required to drive the train, we
attach a drum to one of the axles of the train and hang a weight therefrom by
means of a flexible cord coiled upon the drum. The weight is sufficiently heavy
to just overcome the friction of the train, but the worm gearing does not permit the
weight to drive the armature spindle. With this arrangement the motor merely
regulates the speed of the train acting in an analogous manner to the escapement of
a clock.
The weight may be made of iron or steel and be acted upon by a fixed coil as
described in the Specification to Patent No. 7484 1896.
In a modification of our invention there is no mechanical connection between
the motor and the train, the latter being driven by a ratchet wheel and pawl or by
an equivalent. The pawl is moved by an electro-magnet, the circuit of which is
closed by a rotary contact maker fixed on the meter armature spindle. The
magnet circuit being closed once in each revolution of the armature, the pawl or
equivalent drives the ratchet wheel forward one tooth for every revolution. The
extra friction due to the rotary contact may be eliminated by arranging the com-
mutator brushes so that they serve to alternately make and break the circuit of the
electro magnet, one or more times in every revolution of the armature. In another
modification for the same purpose one of the armature coils has the coil of a small
electro magnet in series with it. The iron core of this electro magnet is a cylinder
fixed to and concentric with the armature spindle. Immediately below or above
the lower or upper pole of the cylindric core a permanently magnetised pole in the
form of a ring round the spindle (but not attached thereto) is placed. The ring
pole is at one end of a balanced lever, and the reversal of polarity of the electro
magnet, which takes place twice in every revolution of the meter armature, causes
the lever to alternately move up and down. This motion is utilised to work a
pawl which drives a ratchet wheel in connection with the train or to operate the
said train in any convenient or equivalent manner, or to merely operate a check
escapement device upon a self-driving counting train. And in order that our
invention may be the better understood we will now describe it with reference to the
accompanying drawings and to the letters and figures marked thereon.
Figure 1. shews a meter with its axle magnetically pivotted, and the train driven
by a weight, and the speed of the latter controlled by worm and gearing.
Figure 2. shews a modified form of our meter, in which the induction for
magnetically pivotting the axle is drawn from the magnets used for the Foucault
brake, and the train driven by means of an electro-magnet which imparts a
reciprocating motion to a magnetised lever.
Figures 1 and 2 show two forms of our magnetic pivot.
Figures 3 and 4. are longitudinal and transverse sections of our commutator.
Figure 5. shews the arrangement of the commutator brushes.
Figure 6. shows our device for driving the train by means of a rotary contact
maker attached to the axle, and

page_text: Figures 7, 8 and 9. show three modifications of our electro magnetic device for
driving the train.
Figure 10. shows a longitudinal and transverse section of a modified commutator.
In Figure 1, which represents a motor meter of the Ayrton-Perry type,-A is the
axle which may be made of soft iron or steel pivotted at the bottom in a jewelled
centre or cup J, and magnetically pivotted at the top. When the attractive, force
of the pole N is too small to support the whole weight of the axle and parts attached
thereto, the bottom pivot of the axle rests in the centre or cup jewel J, and the
magnetic pivot P is held centrally immediately beneath but not touching the
upper jewel J. This jewel has a flat under surface as shown in Figure 1' and a
hardened steel point is let into the pivot P in order that it may rest against J2 in
the event of the attractive force being greater than the weight to be supported.
This jewel, J2, merely serves to prevent the axle from rising, and in no way guides
the steel point so that the pivot P is always free to take up its position in the axis
of the magnetic system. With this form of our magnetically pivotted axle it is
immaterial whether the axle runs on the top or bottom jewel, and in practice we
adust the pole N until the axle will run on whichever jewel it is brought into
contact with.
D. is the armature, preferably having a drum winding and connected in the
ordinary manner to the commutator C. The armature is connected by means of
brushes (not shown) in shunt to the work being measured, a non-inductive
resistance being connected in series with the armature. The armature is closely
surrounded by coils M. M. carrying the main current. The brake is a conducting
disc R, attached to the axle and adapted to rotate between the poles of the brake-
magnets B. B. The counting mechanism or train is driven, or its speed controlled,
by means of a worm G, engaging in a worm wheel attached to an axle T, which
may conveniently be the first axle of the train. One of the axles of the train,
preferably the last, may have a drum attached to it on which is wound a cord
supporting a weight U, the function of the weight being to overcome the friction
of the train, so that the armature axle merely controls the speed and does not have
to do any work in driving the train. The weight of the axle and parts attached
thereto is supported by means of a fixed magnet N. S. having its lower pole N
turned down to the same diameter as the axle, the upper end of which, P, forms
the magnetic pivot. The magnet, N. S. may be made adjustable in a vertical
direction so as to provide means for adjusting the magnetic attraction between N
& P until it exactly suffices to support the weight of the axle.
Figure 2. Shows a modified form of our meter in which the brake takes the form
of a cylinder R, and a compound magnetic system provides the induction necessary
for the brake, and also that for the unipolar magnetic support of the axle. With
this modified arrangement of parts the magnetic induction required for magneti-
cally pivotting the axle is conveniently drawn from the similar poles N1, N2, of
the brake magnets conjoined as a single pole. For this purpose an iron yoke I
joining the poles N1, N2, has an adjustable supporting pole, N, screwed into it, the
supporting pole fits within a fixed bracket Q, to the lower surface of which a thin
metal plate K is clamped by means of a ring V. The upper jewel is dispensed
with in this modification. The axle has no guide or support at the upper end, the
magnetic attraction between N and P sufficing to keep the axle accurately in the
centre of rotation. The ring V merely serves to prevent the axle from being
accidentally displaced sideways beyond the range of the magnetic forces. With
this form of magnetic pivot and supporting pole (shewn more clearly in Figure 2)
it is necessary to adjust the pole N so that the axle will always run on the bottom
jewel, so that should it by chance touch the plate K, it will fall again until it
rests at the bottom jewel. In Figure 2 the main coils M are indicated only by
dotted lines, one commutator brush his shewn, the other being removed in order
to show the commutator. In carrying out our invention, the axle itself may be
made of hardened steel permanently magnetised, but we prefer to make it of mild
steel or soft iron of the best and most uniform quality obtainable, in order to

page_text: ensure perfect uniformity of permeability (and consequently induction) and there-
fore absence of turning moment due to irregular distribution of induction. The
diameter of the magnetic pivot and the supporting pole is determined by the
weight to be supported and the distance or air gap between the pivot and pole.
This distance cannot be reduced indefinitely since with a very small air gap it
is difficult to adjust the attractive force accurately, and it is moreover desirable
to provide some such means for preventing the magnetic pivot from coming into
contact with the supporting pole as are shown in Figs. 1 & 2, namely a jewel J
or a plate K or other like device. We find about 1/100th of an inch to be a con-
venient distance between the magnetic pivot and its supporting pole, and with a
soft iron or mild steel axle about 1/5th inch in diameter a total weight of over a
quarter of a pound can be supported. If the weight to be supported is less than
this, it is preferable to diminish the diameter of the pivot and pole, rather than
increase the length of air gap between them; in short the magnetic pivot should
always be made as small as is consistent with a fairly long air gap. The induction
density in the supporting pole should of course be as high as possible, and for this
purpose we sometimes make the pole conical as shewn in Fig. 1 and Fig. 1.
It is to be clearly understood that our magnetic pivotting dispenses with the
necessity for any guide to keep the top pivot central, thus entirely eliminating
that source of friction. The only friction experienced by our magnetically pivotted
axle is that due to the very slight unbalanced pressure in a vertical direction
against either the top or the bottom jewel, and by careful initial adjustment this
may also be practically eliminated.
When the induction for our unipolar means of support is drawn from a com-
pound magnetic system, such as that shown in Fig. 2, it is necessary that the
magnetic axis of that part of the system which is used to support the axle shall
be vertical, and in line with the rotational axis of the axle. This condition is
fulfilled in the arrangement shown in Fig. 2, by making the supporting pole
project a sufficient distance below the yoke. It is also desirable to have such
poles of the compound magnetic system as may be required for the brake, but
which are not wanted for our unipolar support, arranged in symmetrical positions
with respect to the supporting pole and the axle, and at a sufficient distance there-
from to ensure the entire absence of any disturbing effects on the magnetic
supports due to their stray field. Fig. 2, shows a compound magnetic system which
we have found well adapted to the purpose in view, but other modifications would
work equally well provided the essential conditions and precautions set forth
herein are duly observed.
One form of our commutator is shewn in Figs. 3 & 4. The lower end of the
axle is drilled to receive a fine steel pivot P. Insulating collets d. d, drilled with
one central hole and a concentric ring of holes, corresponding in number to the
number of sections in the commutator, are driven tightly on the pivot.
The wires g. 9. are fitted tightly in the concentric holes, and bent at a right
angle at the upper end of the commutator in order to receive the connecting
wires w. w. from the armature. The holes in the collets are conveniently drilled
by means of a pantograph drilling machine, similar to the pantograph engraving
machine in common use.
After building up the commutator the peripheral surface may be ground down
until about half the thickness of the commutator sections has been removed. In
this way the commutator surface is left cylindrical and accurately concentric with
the pivot P. It is however not essential to grind the commutator sections in this
way, since the commutator is easily made less than 1/16th of an inch in diameter,
and the absence of a truly cylindrical surface does not add appreciably to the
friction of the brushes.
Fig. 5. shows the commutator and brushes in plan.
The brushes consist of a light rod or bow r strung with a number of fine wires h
and pivotted on a fixed block at i i.
The brushes are maintained in contact with the commutator by means of a

page_text: spring passed through insulating bushes in the bows r r. This arrangement
provides for a readily adjustable and elastic pressure of the brushes on the com-
mutator, and also ensures exact equality of pressure on the two sides of the
commutator.
In Figure 6 an insulating drum is shown attached to the axle of the meter carry-
ing a metallic segment b, which once in every revolution of the axle makes electrical
connection between the springs ss, thus closing the circuit of an electromagnet e
which attracts an armature a fixed in a lever pivotted at Z. This lever is normally
held against a stop H by means of a balance weight Y. The reciprocating motion
imparted to the lever, during the rotation of the meter axle, serves, by means of a
pawl, to drive a ratchet wheel X attached to an axle T, which may conveniently be
the first axle of the train.
In
It will be noticed that this method of driving the train involves a certain
amount of frictional resistance to the motion of the armature axle; and accordingly
we prefer to adopt one or other of the various modifications as hereinafter described,
of our electromagnetic device, which serves to impart the required reciprocal
motion to a lever, without adding in any way to the work done by the motor.
the arrangement for driving the train shown in Figure 2, the reciprocating lever L
is made of magnetised steel, having one pole O in the form of a ring round the
meter axle, but not touching it. Immediately beneath the ring O an electromagnet
having a cylindrical core E is fixed to (and concentric with) the axle A. The coil
of this electromagnet is connected in series, either with one of the coils in the
armature, or with the connecting wires between an armature coil and the com-
mutator. In the first case half the total current in the armature circuit traverses
the electromagnet, and reverses twice in each revolution, in the second case the
whole of the armature current traverses the electromagnet during the time the
particular section of the commutator, with which it is in series, is under the brush,
the current in this case also being first in one direction and then in the other.
The successive reversals of the polarity of the electromagnet, cause the lever L
to reciprocate between the stops H, and drive the ratchet wheel X attached to the
train. The lever L is balanced by means of a weight Y. This device may be
modified in many ways, for example the electro magnet may have two separate
windings, each connected in series with one armature coil, the armature coils
selected for this purpose being of course corresponding coils in the two halves of
the drum winding. In another modification the lever L is made of soft iron and
magnetised by a fixed coil around the body of the lever but not touching it, a
form which is available for use with alternate currents.
In another modification the lever L, Figure 2, is made of soft iron and simply
acts as the keeper of the electromagnet, in this case the weight Y is arranged to
bring the lever against the upper stop, since the electromagnet will attract the ring
pole of the lever every time the current traverses its coils without regard to its
direction.
The coil of the electromagnet must, in this modification, be connected in series
with the wire joining one of the armature coils to the commutator. It will be
readily understood that in this case the lever will make two strokes to each
revolution of the axle A.
In Figure 7 we show our preferable arrangement of train driving magnet when
the meter is intended to be used with direct currents. The lever L is either of
magnetised steel, or may be made of soft iron magnetised by induction drawn from
the brake magnets, or separately magnetised by means of a coil. The ring pole O
embraces an electro-magnet E formed by winding a coil direct on the axle, so tha
the latter forms the core of the electro-magnet. The successive reversals of the
current in the electromagnet cause the ring pole 0 to be attracted alternately
upwards and downwards, the motion being as before limited by stops H H.
In Figure 8 is shown a modification more particularly adapted for use wit
alternate currents. In this case the core of the electromagnet is formed by the
axle A & its coils are wound in two sections E¹ & E², coupled together in such a

page_text: manner as to produce a consequent pole at their adjacent ends. An iron disc may
be fixed on the axle between the two adjacent ends of the coils to increase the
magnetic induction proceeding from this pole. The windings of the electro-
magnets are connected to the armature in one or other of the ways already
described. With this modification the lever is formed of non-magnetic material
and carries at one end a coil O', which may conveniently form part of the
resistance in series with the motor armature, the current being led to the coil by
means of flexible connections. The successive reversals of polarity of the central
pole of the electromagnet drive the coil O' up and down, driving the train in the
manner already described.
Figure 9 is a modification of Figure 8, the coil O' being replaced by an electro-
magnet O² having a soft iron core with ring poles 03 and 04 at either end. The
necessary force for moving the lever is in this case due to the magnetic induction
from the poles 03 and 0 passing through the windings E and of the electro-
magnet on the axle A. The current for the exciting coil of the. electro magnet on
the lever is obtained in the manner described in connection with Figure 8. It is
to be clearly understood that the only essential condition for the successful working
of our electro magnetic train driving or controlling device, is that the mechanical
force due to the electromagnet should act in the direction of the axis of rotation
of the axle, so that there is no mechanical force which can have a component to
produce a turning moment on the axle. The various modifications of the device
which we have described and shown in the drawings are these which we have
found well adapted for the purpose, but we may adopt other modifications in which
the above essential condition is fulfilled.
For example the train may have an independent driving force applied to it
by means of a weight, spring, small electro-motor, or other known and suitable
means, and a lever L instead of driving the train by means of the ratchet and pawl
motion shown, may be caused to merely control the speed at which the train is
driven by other means by a known escapement device or any known step by step
releasing mechanism. A modification of our commutator is shown in Figure 10
which shows a transverse and axial section of the same. The wires g. g. are
covered with silk or other suitable insulating material and are clamped round the
pivot by means of insulating clamping rings e e. After completion, the insulat-
ing material on the peripheral surface of the wires g. 9. is scraped off, and the
said surface may be ground or turned true in the manner already described.
We have described our magnetic pivot in connection with a motor meter of the
Ayrton-Perry type in which we have applied it, but is is equally applicable to
any motor meter.
For example in the various forms of alternate current meters in which an
induction motor is employed, our magnetic pivot may be usefully employed to
support the weight of the rotating parts. Again our magnetic pivot is particu-
larly applicable to the various types of motor meters in which a Foucault brake is
employed, the necessary magnetic induction for the supporting pole being con-
veniently obtained from the brake magnets in a similar manner to that shown in
Figure 2.
We have shown permanent magnets as the means for producing the induction
for the supporting pole of our magnetic pivot, but although we consider permanent
magnets to be preferable, we do not confine ourselves to their use, and in cases
where permanent magnets are not suitable for any reason we substitute electro
magnets for them.
For example, in some types of motor meter the brake
are electro magnets, and in such meters the magnet for the supporting pole may
magnets
conveniently be an electro magnet also, or the supporting pole may derive its
nduction from the brake magnets in a similar manner to that described in
connection with permanent brake magnets.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1st. In a motor meter with its operative axle vertical, unipolar means for
magnetically supporting such axle substantially as described.
2nd. In a motor meter having an armature and a Foucault brake attached to
and moving with a vertical axle, unipolar means for magnetically supporting and
pivotting the said axle, in combination with a counting train adapted to be driven
or controlled by a motive force, dependent on the rotation of the said axle, but
not deriving its energy from the mechanical energy of such rotation, substantially
as described.
3rd. In a motor meter, a vertical axle of magnetic material, adapted to rotate
with limited vertical play between upper and lower end bearings, in combination
with a single magnetic pole situated above the said axle, and adapted to provide a
magnetic support and pivotal guidance to the said axle, substantially as described.
4th. In a motor meter with a Foucault brake, the combination with the brake
magnets of a vertical axle magnetically supported and pivotted by unipolar means,
adapted to be magnetised by or in conjunction with the brake magnets, substan-
tially as described.
5th. In a motor meter, the combination with the meter axle of a counting train
operated by a weight, cord, and drum, together with a worm gear between the
meter axle and the train, to control the speed of the said automatically operated
train, substantially as described.
6th. In a motor meter, the combination of the meter axle with an electro-
magnetic device on the said axle, adapted to impart a reciprocating motion in the
direction of the axis or rotation of the said axle, to means for operating or con-
trolling a counting train, substantially as described.
7th. In a motor meter, the combination with the meter axle of a contact attached
to the said axle, adapted to close the circuit of a fixed electro-magnetic device,
operating reciprocating means for driving or controlling a counting train, sub-
stantially as described.
8th. In a motor meter, a commutator formed by a number of parallel insulated
wires, closely surrounding a part of the motor axle having the smallest practicable
diameter, substantially as described and for the purpose set forth with reference to
Figures 3 and 4.
1000
FELL & JAMES,
1, Queen Victoria Street, London, E.C., Agents for the Applicants.