Year: 1899

page_text: Date of Application, 13th Sept., 1899
Complete Specification Left, 13th June, 1900-Accepted, 1st Sept., 1900
We, CHAMBERLAIN & HOOKHAM LIMITED, Manufacturers, and SYDNEY HOLM-
WOOD HOLDEN, Engineer, all of 4, New Bartholomew Street, Birmingham, do
hereby declare the nature of this invention to be as follows:-
Our invention relates to that class of meters in which an electro-motor rotates
against a foucault or other brake at a speed proportional to the current or energy
to be measured.
The first object of our invention is to provide new means for correcting errors
introduced by static or fluid friction. The second object is to make an improved
form of meter in which one of the above mentioned means of correcting errors
is utilized as a main part of the meter. The following are among the methods
in which we may carry out our invention.
In carrying out the first object of our invention we compensate for an error
either fast or slow at full load (1) by placing a thermo-electric couple (say a
bismuth-antimony bar) in shunt to the armature so connected that when the
junction is heated the current produced assists or opposes the motor.
This heat
may be furnished by the current passing through the junction or through a coil
surrounding it (2) by shunting the motor with a piece of pure bismuth so arranged
that the current to be measured produces a magnetic field through it and so
increases its resistance.
In order to compensate for static friction we may have (1) a thermo pile as
above in parallel with the motor, the junction being heated slightly by a coil
carrying a "shunt current" and so giving a constant slight driving force (2)
we may press a lever (worked by the current to be measured) against the spindle
of the motor so that the static friction increases as the speed (3) we may suspend
the permanent magnet which produces the foucault brake in such a way that it
is drawn into a more effective position as the current increases (4) we may attach
a small coil moving in a magnetic field to the motor spindle with a contact maker
shunt current" passes
so arranged that during a portion of the revolution a
"
through the coil causing it to tend to rotate in the same way as the spindle.
In carrying out the second object of our invention we make a motor meter
consisting of a disc or cylinder armature immersed in mercury and pass a con-
stant powerful current through it from a thermo pile heated by a shunt current.
The current to be measured produces the field in which the armature rotates. Its
driving force being thus proportionate to the current, a copper disc attached to
the spindle moving in the field of a permanent magnet will form an appropriate
brake. One of the above mentioned corrections (or other well known ones) for
static and fluid friction may be applied.
DL: 11th dow of Santamber 1899

page_text: We, CHAMBERLAIN & HOOKHAM LIMITED, Manufacturers, and SYDNEY HOLM-
WOOD HOLDEN, Engineer, all of 4, New Bartholomew Street, in the City of Bir-
mingham, 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:-
.
7:
877
Our invention relates to that class' of meter in which an electro-motor, rotates
against a foucault or other brake at a speed proportional to the current or energy
to be measured.
11.11
The first object of our invention is to provide new means for correcting errors,
introduced by static or fluid friction or other causes. The second object of our
invention is to utilize one of the above mentioned means of correcting errors as
a main part of a meter.
"
Our invention consists in compensating for an error either fast or slow at high
loads:-
(1). By placing a thermo-electric couple in parallel with the armature, so.
connected that, when the junction is heated, the current produced assists or
opposes the motor.
The heat is furnished by the current to be measured passing.
either through the junction or through a coil surrounding it.
(2). By shunting the motor with a piece of pure bismuth so arranged that
the current to be measured produces a magnetic field through the bismuth and
so increases its resistance.
Our invention further consists. in compensating for static friction:-
(1) By placing a thermo-pile in parallel with the motor, the junction being
heated slightly by a coil carrying a shunt current so that a constant current is
produced by the thermo-pile and sent through the motor, giving a slight steady
driving force.
1
L
(2). By suspending and controlling the position of the permanent magnet
which produces the foucault brake in such a way that it is drawn into. a more
effective position as the current increases.
(3). By attaching to the motor spindle a small coil moving in a constant
magnetic field and having a contact maker so arranged that during a portion of
the revolution a shunt current passes through. the coil, causing it to tend to
rotate in the same way as the spindle.
Our invention further consists in causing the static friction to be proportional
to the load by causing the current to be measured to act so as to press a brake.
against a rotating part of the motor and thus increase the friction when the:
current increases.
Our invention further consists in applying a pile in an electricity meter as a
main part of the meter.
In the accompanying drawings which illustrate our invention:
r
Figures 1 to 5 inclusive illustrate a continuous current meter in whichi compen-
sation for an error either fast or slow at high load made by placing a thermo-
electric couple in parallel with the armature and adapted to be heated by the
current to be measured.
Figures 6-10 inclusive illustrate two devices for compensating for static
friction.
Figures 11 and 12 illustrate a device for making the friction of the motor pro-
portional to the load.
Figures 13 and 14 illustrate a motor meter in which the current which passes

page_text: while the current to be measured produces the field in which the armature rotates.
Referring in the first place to Figures 1-5 inclusive a continuous current
meter is there represented which comprises one form of that part of our inven-
tion whereby compensation is made for an error either fast or slow at high loads
by placing a thermo-electric couple in parallel with the armature so as to send a
current through the armature either in the same or in the opposite direction to
the current to be measured, thereby either assisting or opposing. the rotation of
the armature.
"In this form the junction of the couple is heated by the current to be measured
passing through a coil surrounding the junction.
Figure 1 is a front elevation of the meter removed from its case.
Figure 2 is a back elevation of the same.
Figure 3 is a section of the same on the line A A of Figure 1.
Figure 4 is a section taken on the line B B of Figure 3, only certain parts
being shown.
1
Figure 5 is a plan of the mercury containing vessel with the armature and
mercury removed.
The
In this meter a permanent magnet a has its poles b and c connected by the bar
of soft iron d, which is made magnetically discontinuous by the insertion of a
piece of brass in the middle. Below this bar of soft iron is the containing vessel e
adapted to enclose the armature f (see Figure 4) immersed in mercury g. The
armature is mounted on the spindle and conveys the current to be measured
across its diameter from the terminal k to the terminal or vice versa.
mercury containing vessel e is formed of a ring of insulating and non-magnetic
material m and a block of soft iron n partially divided by a piece of non-magnetic
material o. The spindle h is arranged to actuate by its rotation the counting
mechanism enclosed in the frame p. This counting mechanism may be of any
ordinary construction. Most of the lines of force passing along the bar d from
the permanent magnet a will leave the bar dat the points and r and pass
through the block n. These lines of force will therefore pass through the arma-
túre at right angles to the line of the electric current flow and will therefore
cause the armature to rotate in a manner that is well known. This arrange-
ment and construction of armature and permanent magnet forms no part of this
invention.
In any convenient part of the meter is placed the bar forming the thermo-
electric couple composed of two different metals, preferably bismuth and anti-
mony is the bismuth and t the antimony. The current from the positive
terminal u of the 'meter passes (see Figure 2) through the coil surrounding the
junction of the bismuth and antimony and then to the positive motor terminal k.
Thence it passes through the motor and from the negative terminal of the
motor to the meter negative terminal w. The antimony t is connected by the
wire to the motor positive terminal and the bismuths is similarly joined to
the motor negative terminal! by the wire y. The bismuth-antimony couple will
therefore, when its junction is heated by the current in the coil v augment the
current passing through the motor. The connections of the wires and y may
however be reversed so as to diminish the current passing through the motor.
RC
Instead of heating the junction of the bismuth and antimony by passing the
current to be measured through the coil we may heat the junction by passing
the current through the bismuth and antimony couple itself.
Instead of using a thermo-electric couple to augment or diminish the current
passing through the motor, we may shunt the motor with a piece of pure bis-
muth and employ the current to be measured to produce a magnetic field through
the bismuth and thereby increasing its resistance so that less current passes
through the bismuth shunt and more through the motor.
In order to compensate for static friction, we may use the thermo-electric device
hereinbefore described with this difference that the junction of the bismuth and
19

page_text: :.
antimony (or other thermo-electric couple) is heated by a shunt current instead of
by the current to be measured. By this means the thermo-pile will send a
constant current through the motor which will produce a constant driving force.
This may be so proportioned as to exactly compensate for static friction.
Our second device for compensating for static friction is shown according to
one modification in Figures 6, 7, and 8 as applied to an alternating current
meter.
This form of our device consists in suspending the permanent magnet which
produces the foucault brake by a fine wire in such a way that it is drawn into a
more effective position as the current increases by the action of an electro-magnet
energised by the current to be measured.
Figure 6 shows the meter in front elevation.
Figure 7 is a sectional plan of part of it, the section being taken on the
line X X of Figure 6.
Figure 8 is a vertical section taken on the line Y Y of Figure 6.
The disc 2 rotates in a manner now well known by the joint action of the
magnet 3 energised by a shunt current and having extended poles 6 and 7 and
the coils 4 and 5 conveying the current to be measured and situated under the
disc and between it and the lower pole 7. The permanent brake magnet 8 has
its poles 9 and 10 respectively above and below the disc. This brake magnet is
attached to the spindle 11 the upper end of which has a bearing in the bar 13
which is preferably constructed of a non-magnetic material. The bar 13 is
attached to the poles of a distorted horse-shoe magnet 14 (Fig. 8); and this
magnet is fixed to the frame of the meter or to a standard connected thereto.
Mounted on the spindle 11 above the bar 13 is a bar armature 15 which is thus
situated between the poles of the magnet 14. To the top end of the spindle 11
is attached a fine wire 16 the other end of which is fixed to an adjusting screw 17
set in a bracket 18 fixed to the frame of the instrument or to a standard sup-
ported thereon. The adjusting screw may be provided with a pointer 19 adapted
to indicate on a scale 20 the amount of torsion of the wire. The lower end of
the spindle 11 is also attached to a torsion wire 60 connected to an adjusting
screw 61 which passes through the bracket 12 secured to the frame of the meter.
The wire is set so as to be in torsion when the armature is in line with the poles
of the magnet 14. In this position the brake magnet 8 is in its most effective
position to retard the motion of the disc 2. The angular motion of the brake
magnet may be limited by suitable stops 21. The magnet 14 is energised by
coils 22 carrying the current to be measured so that, as this current increases,
the armature 15 wili be pulled more into the line of the electro-magnet poles
and the brake magnet S thus forced into a more effective position. Therefore
the braking action on the disc will increase when the current increases; and the
position of the brake magnet and the torsion of the wire may be so adjusted
that the variance from proportionality of the braking action of the brake magnet
will compensate for the variance from proportionality of the static friction of the
motor and counting mechanism. The counting mechanism is enclosed in the
frame 23 and may be actuated in any usual manner from the disc 2.
It will be obvious that the change of position of the suspended magnetic brake
may be effected in other ways than that above described without departing from
our invention.
For example the brake magnet may be so suspended and controlled by a suit-
able spring that the greater drag due to increased speed will pull over the sus-
pended magnet into a more effecting braking position against the controlling
spring and thus effect the desired correction of the meter rate.
In every case however the magnetic brake must be so pivoted and positioned
with regard to the controlling forces that changes of the meter rate are caused
by its angular displacement.
Our third device for compensating for static friction is shown according to one
modification in Figures 9 and 10 as applied to an alternating current meter.

page_text: This device consists in attaching to the motor spindle a small coil moving in a
constant magnetic field and having a contact maker so arranged that during a
portion of the revolution of the spindle a shunt current passes through the coil,
causing it to tend to rotate in the same way as the spindle is rotating and there-
fore to augment the turning moment on the spindle.
Figure 9 shows the meter in front elevation and,
Figure 10 is a partial sectional plan, the section being taken on the line D D
of Figure 9.
This disc 2 and the means for driving it are the same as in the meter just
described and illustrated in Figures 6, 7 and S.
The
Instead however of having a moving brake magnet, we provide a fixed brake
magnet 24 having its poles 25 and 20 respectively above and below the disc 2.
On the spindle 31 on which is mounted the disc 2 we support a bobbin 30 having
a coil of fine wire 27, the axis of the bobbin and coil being horizontal. To the
electro-magnet 3 we attach adjustably the supports 28 which are of non-magnetic
material and support the small auxiliary electro-magnet 29 in such a position that
the line joining the poles of this magnet passes through the bobbin 30.
magnet 29 may be supported otherwise than from the magnet 3, but we find it
convenient to support it from this magnet. The magnet 29 and the bobbin
coil 27 are energised by a shunt current during a portion of the revolution of the
spindle 31. This is accomplished by means of a wire 33 forming one end of the
coil 27 arranged along the spindle 31 and adapted to make and break contact
with a spring 34 attached to the insulated block 35 which may be rigidly fixed
to any suitable support. The coil 36 which energises the magnet 29 is in series
with the coil 27 on the bobbin 30 and with a resistance coil 37, being joined to
A shunt
the spring 34 by a wire 38 and to the resistance coil 37 by a wire 39.
current passes through this circuit which current is in parallel with the shunt
current which energises the electro-magnet 3. The electro-magnet 29 can be
moved up and down by means of the adjustable supports 28 so as to be situated in
a more or less effective position with regard to the bobbin 30. By this means
and by suitably adjusting the resistance 37, the auxiliary turning moment on the.
spindle caused by the action of the magnet 29 on the coil 26 can be made to com-
pensate for the static friction of the meter.
Another of our devices for causing the static friction to be proportional to the
load is shown, according to one modification as applied to an alternating current
meter, in Figures 11 and 12.
According to this device the current to be measured acts so as to press a brake
against a rotating part of the motor and thus increase the friction when the
current increases.
igure 11 shows the meter in front elevation situated in its case from which
the front and back doors are removed.
Figure 12 is a sectional plan of the same, the section being taken on the
line EE of Figure 11.
This meter in its main features resembles the one just described. Instead
however of being provided with the auxiliary electro-magnet, and having the
bobbin attached to the vertical spindle of the rotating disc, we provide a coil 41
adapted to convey the current to be measured. In this coil is pivoted an iron
or steel bar 42 which will therefore tend to take up a position in line with the
axis of the coil when a current passes through the coil Attached to the bar 42
is a wire 43 arranged so as to press against the rotating disc 2 when the bar is
deflected. Therefore the stronger the current passing through the coil 41, the
greater will be the pressure with which the wire 43 is pressed against the rotat-
ing disc. It is obvious that, instead of having a wire such as 43, we may employ
any suitable form of brake and make it act on any moving part of the motor.
By this means we can so augment the friction of the motor as to make it propor-
tional to the load.
The last part of our invention is shown according to one modification in

page_text: Figures 13 and 14. In this modification of our invention we supply a constant
powerful current to a motor meter from a thermo-pile heated by a shunt cur-
rent while the current to be measured produces the field in which the armature
rotates.
Figure 13 shows the motor meter partly in front elevation, and partly in
section, some parts being removed for the sake of clearness.
Figure 14 is a sectional plan of the meter, the section being taken on the
line F F of Figure 13, and the electric circuits being shown diagrammatically
for the sake of clearness.
The armature 45 is mounted on the vertical spindle 46 which also carries the
brake disc 47. The armature rotates in mercury contained in the vessel 48 formed
by the iron bobbin 49, the annulus 51 of insulating material, and the metal
cylinder 52 inserted in the centre of the insulating annulus. The lower end of
the cylinder 52 is attached to the centre of the bismuth block 53 which has
three radial arms 54 to each of which is attached a bar of antimony 55. The
bismuth may be in one piece or in three pieces fixed together. To the outer
ends of the antimony bars are attached the copper ribbons 56 which are curved
and flexible so as to allow of the expansion and contraction of the bismuth and
antimony. The other ends of the copper ribbons are connected to the bobbin 49.
The current to be measured passes in a coil 58 round the bobbin 49 and so creates
a magnetic field in which the armature 45 rotates.
A shunt current passes
through the coils 59 which enclose the junctions of the bismuth with the anti-
mony. The coils 59 are arranged in parallel with each other but they might be
arranged in series if desired. These coils heat the junctions of the bismuth and
antimony and therefore cause a current to flow from the cylinder 52 to the
bismuth block, then outwards through the antimony bars, then along the copper
ribbons to the iron bobbin and thence through the mercury and the armature
back to the cylinder 52. When shunt currents are sent through the coils 59, a
constant current will therefore be sent through the armature and, as the latter
rotates in a magnetic field whose strength is proportional to the velocity, will
indicate by its speed of rotation the amount of current passing through the meter.
It will be evident that a thermo-pile may be used in many other ways in direct
current or alternating current meters as a main part of the meter without depart-
ing from our invention. In alternating current meters we use the current to be
measured to heat the thermo-pile junction.
It is obvious that the bismuth and antimony may be reversed, and the current
sent in the reverse direction. It is also obvious that other metals and alloys
than bismuth and antimony may be employed for the thermo-pile and that the
construction of the thermo-pile may be varied, without departing from our inven-
tion.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is: :-
1. In electricity meters compensating for errors of registration by means of
a thermo-electric couple heated by an electric current.
2. In electricity meters, compensating for an error either fast or slow at high
loads by placing a thermo-electric couple in parallel with the armature, so con-
nected that, when the junction of the couple is heated, the current produced
assists or opposes the motor, the heat being furnished by the current to be
measured passing either through the junction or through a coil surrounding it.
3. In electricity meters, compensating for an error either fast or slow at high
loads by shunting the motor with a piece of pure bismuth so arranged that the
current to be measured produces a magnetic field through the bismuth and so
increases its resistance.
4. In electricity meters compensating for static friction by placing a thermo-
pile in parallel with the motor, the junction being heated slightly by a coil

page_text: carrying a shunt current so that a constant current is produced by the thermo-
pile and sent through the motor, giving a slight steady driving force.
5. In electricity meters compensating for static friction by suspending the
magnetic brake in such a way that it passes into a more or less effective position
as the current changes and thereby automatically alters the meter rate to the
required extent substantially as described.
6. In electricity meters correcting the meter rate by suspending the magnetic
brake in such a way that the position of the brake relatively to the brake disc
is controlled by an armature situated between the poles of an electro-magnet
which is energized by the current to be measured substantially as described...
7. In electricity meters compensating for static friction by attaching to the
motor spindle a coil moving in a magnetic field and having a contact maker so
arranged that during a portion of each revolution a shunt current passes through
the coil substantially as described.
S. In electricity meters, compensating for static friction by attaching to the
motor spindle a small coil such as 27 moving between the poles of an auxiliary
magnet such as 29 energized by a shunt current, the coil having a contact maker
such as 33 and a spring such as 34 so arranged that during a portion of each
revolution of the spindle a shunt current passes through the coil so as to rotate
the coil in the same direction as the spindle substantially as described.
9. In electricity meters a device adapted to make the static friction propor-
tional to the load consisting essentially in a wire or spring such as 43, not carry-
ing current, but operated to come into contact with and press on a moving part
of the meter as required substantially as described.
10. In electricity meters, the combination with a coil such as 41 and a bar
such as 42 of a wire or brake attached to or actuated by the said bar and adapted
to be brought into contact with and pressed against the motor or brake disc sub-
stantially as and for the purpose described.
.
11. In electricity meters, the utilization of a current produced by a thermo-
pile heated by a main or shunt current to take the place of the said main or
shunt current.
12. In electricity meters, supplying a constant current to the motor from a
thermo pile heated by a shunt current, while the current to be measured pro-
duces the field in which the armature rotates.
13. In electricity meters, the combination of a block of bismuth such as 53
having arms such as 54 joined to bars of antimony such as 55, the junctions of
the bismuth with the antimony being surrounded by coils such as 59 heated by a
shunt current, and the bismuth and antimony being connected respectively to the
terminals of the motor, so that the current generated by the heating of the bismuth
and antimony junctions is supplied to the motor," while the current to be
measured produces the field in which the armature of the motor rotates, sub-
stantially as described.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and 25, Cross Street, Manchester,
Agents.