Year: 1897

page_text: We, CHAMBERLAIN and HOOKHAM LIMITED, Manufacturers, and SYDNEY HOLMWOOD
HOLDEN, Engineer, of 4, New Bartholomew Street, in the City of Birmingham,
do hereby declare the nature of this invention to be as follows:-
Our invention is applicable to motor meters in which the current to be measured
passes through the armature and through a series coil which produces or effects
It has for its object to
the field in which the armature or the brake disc revolves.
make such a meter capable of running in the reverse direction when the current
is reversed and reading accurately.
In order to obtain this result, two series coils are provided wound in opposite
directions over the same or corresponding parts of the meter and so connected to
the meter and the external circuit that the currents in one direction pass through
one coil and currents in the other direction through the other coil thus producing
or affecting the magnetic field in the same sense.
It may sometimes be advisable that the meter should run slower in one direction
than in the other and this may be accomplished by putting fewer turns on one coil
than on the other, or by arranging that when the current is entering the meter by
one coil a greater proportion of it shall pass through a shunt than when it enters
through the other.
In the above and other cases it is often desirable to be able to regulate the
amount of current passing through a coil by shunting it and to vary this without
the necessity of soldering up connections after adjustment. This may be accom-
plished by permanently soldering a shunt of rather higher resistance than is
probably required to the two ends of the coil and then introducing the current at
variable points along the shunt. This last improvement is applicable also to non-
integrating meters such as ammeters and voltmeters.
We, CHAMBERLAIN & HOOKHAM, LIMITED, Manufacturers, and SYDNEY HOLMWOOD
HOLDEN, Engineer, of 4, New Bartholomew Street, in the City of Birmingham, do
hereby declare the nature of this invention, and in what manner the same is to be

page_text: performed, to be particularly described and ascertained in and by the following
statement:-
Our invention relates to motor meters in which the current to be measured passes
through a series coil which produces or affects the field in which the armature or
the brake disc revolves, and has for its object to make such meters capable of
running in the reverse direction, and reading accurately when the current is
reversed:
One part of our invention consists in providing two series coils which are wound
in opposite directions over the same or corresponding parts of the meter, and so
connected to the meter and the external circuit that the currents in one direction
pass through one or both coils and currents in the other direction pass through the
other coil, and thereby producing or affecting the magnetic field in the same sense.
It may sometimes be advisable that the meter should run slower in one direction
than in the other, and this may be accomplished by putting fewer turns on one
coil than on the other, or by arranging that when the current is entering the meter
by one coil a greater proportion of it shall pass through a shunt than when it enters
through the other.
In carrying our invention into effect according to one modification and referring
to the accompanying three sheets of drawings,-
Figure 1 is a front elevation of a direct current electricity meter with our present
invention applied to it.
Figure 2 is a side elevation of the same, and Figure 3 is a diagram showing one
arrangement of such a meter in a circuit.
In the figures A is the base of the instrument. B is the permanent inagnet with
its pole pieces-B1, B2, B³. The chamber C contains the disc armature and the
necessary mercury.
D is the brake disc. To the pole piece B2 we attach horns or
auxiliary magnets E and E2 wound with series coils F1 and F. The coils F¹ and F2
are wound so that they magnetize their cores in the same sense: that is, so that
their poles attached to the pole piece B2 are of similar polarity whether the battery
is being charged or discharged. Three terminals are provided marked G, H, and I.
The inner ends of the coils F1, F2, are connected together at F3 and from their
junction a wire is led to the mercury chamber containing the armature of the meter.
From the axis of the armature a wire is led to the terminal I.
The outer end of the coil F" is connected to the terminal G and the outer end of
coil to terminal H.
The circuit in which the meter is placed is shewn in Figure 3.
The terminal G is connected with one of the mains L of the lighting circuit.
Terminal His connected through a switch M to the positive terminal of the
dynamo K. The terminal I is connected to one end of the battery J. The other
end of the battery is connected to the negative terminal of the dynamo K and to
the second main L¹ of the lighting circuit. A switch M is provided in the dynamo
circuit so that the dynamo can be stopped when the battery is alone providing the
current for the lights.
When the dynamo is supplying current to the lighting circuit and also to the
battery the direction of flow in the circuit will be as follows:-From the positive
terminal of the dynamo by way of the switch M to the terminal H of the meter,
then through the coil F2, where it branches, one part passing on through the coil F¹
to terminal G and then through the lamps in the lighting circuit and back to the
negative terminal of the dynamo. The other part passes from the coil F2 through
the armature of the meter and thence by way of the terminal I to the battery J
and from the battery to the negative terminal of the dynamo. When the dynamo
is cut out of the circuit, by opening the switch M, the current for the lighting
circuit is supplied wholly by the battery J and it passes from the battery through
the circuit in the opposite direction to that of the current when charging the
battery.
The current thus flows from the positive pole of the battery by way of the meter
erminal I through the armature of the meter and thence through the coil F1 and

page_text: the terminal G to the main L2 of the lighting circuit. From the main L' it then
passes to the negative terminal of the battery .J.
As the switch M is open no current can pass through the series coil F2 of the
meter.
The coils F1 and E2 are so proportioned to their cores and adjusted to affect the
field in which the armature revolves in such a manner that the meter reads
correctly in one direction with current passing through both coils and the armature
and also reads correctly in the other direction with the current passing only through
the one coil F1 and the armature. It will be observed that the opening of the
switch M has the effect of reversing 'the direction of the current through the
meter and this also reverses the direction of rotation of the meter armature..
In the arrangement above described the meter will run at the same speed in both
directions, but this may be modified so that it shall run slower in one direction
than in the other as described below.
It will be seen that many other arrangements of the meter in the circuit may be
made, currents in one direction being made to pass through one of the series coils
and currents in the other direction to pass through the other coil. In some cases
where we desire to make the meter run slower in one direction than in the other by
one arrangement we wind more turns on one coil than on the other.
In one arrangement of a meter constructed in accordance with our invention
a different constant would be required to give ampere hours or Board of Trade
Units while running in one direction from that required while running in the other
direction but the difference may be so adjusted that a compensation is provided
for the loss in the battery so that the battery would be fully charged when the
meter had returned to zero.
One way
in which we make the meter run slower in one direction than in the
other is by arranging a shunt in the circuit so that when the current is entering by
one coil a greater proportion of it passes through a shunt than when it enters
through the other coil.
In the above and other cases it is often desirable to be able to regulate the
amount of current passing through a coil by shunting it and to vary this without
the necessity of soldering up connections after adjustment. This may be
accomplished by permanently soldering a shunt P, see Figure 1, of rather higher
resistance than is probably required to the two ends of the coil F¹ and then
introducing the current at a point which may be varied along the shunt P by means
of a clamp such as Q connecting by a flexible wire as R to the terminal G. This
last improvement is applicable also to non-integrating meters such as ammeters and
voltmeters.
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 a motor electricity meter series coils producing or affecting the field in
which the armature revolves, to enable the meter to reverse and read correctly when
the current is reversed substantially as described.
2. In a motor electricity meter series coils producing or affecting the field in
which the armature revolves and wound or arranged so that the meter runs more
slowly in one direction than in the other substantially as described.
3. In a motor electricity meter two series coils arranged so that currents in one
direction pass through one coil and currents in the opposite direction pass through
the other enabling the meter to read correctly through its range in either direction
substantially as described.
4. In a motor electricity meter as claimed in the preceding claims having series
coils as described adjusting the coils by means of a shunt or shunts so that the
meter runs slower in one direction than in the other.
•
5. In electricity meters and electricity measuring instruments varying the current
passing through a coil by introducing the current to the coil by means of a shunt

page_text: connecting the two ends of the coil the current being introduced at different points
on the shunt as herein set forth.
6. The improved motor electricity meter and arrangements herein before described
with reference to the accompanying drawings,
Dated this 4th day of Sentomban. 1900
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents: