Improvements in or relating to Ampere-hour Electric Meters.
Year: 1897

page_text: Improvements in or relating to Ampere-hour Electric Meters.
I, GEORG HUMMEL, of Dreimühlenstrasse 3, Munick, in the Kingdom of Bavaria,
Germany, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to an electric meter or counter for continuous currents,
having a coil traversed by the current, and arranged to oscillate in a constant
magnetic field, as I shall describe with reference to the accompanying drawings.
Figure 1 is an elevation partly in section of a meter with diagram plan of its
relay and connections, according to this invention.
Figure 2 is a sectional plan, Figures 3 and 4 shew similar views of a modification.
M is a permanent magnet or a constant electromagnet provided with two pole
pieces cylindrically hollowed. A is a fixed armature.
The spindle a carries a coil S which is traversed by the main current, or a
fraction of it, while the metal bell E which oscillates in the strong magnetic field
acts for damping. For increasing the damping action a disc oscillating between
constant magnets can also be mounted on the spindle a; but this is not shown.
The construction of the new electric meter is generally similar to that of the
galvanometer of Deprez-d'Arsonval.
The mode of operation of the apparatus is as follows:-
The coil S traversed by the current to be measured is deflected in the constant
maguetic field.
This deflection works a reversing commutator or a relay R
Figure 1, whereby alternate reversing of the current at the end positions and
consequently an oscillating movement of the coil is caused to take place.
The arrangement and relative action of the meter and relay will be understood
on reference to Fig. 1. The magnetic windings m n of the relay R are connected
in series in a shunt circuit of the main circuit and both magnets are consequently
active during the vibrations of the coil S.
That magnet to which the relay armature is nearest for the time being, holds it
stationary. On the magnet M are fixed insulated contact springs C1, C2, which are
connected respectively by a lead to the conductor connecting oue of the relay
magnets to the main circuit, while an arm D fixed on the spindle a is connected to
the other ends of the windings of both electro-magnets R. Thus on the arm D
coming in contact with one of the springs C₁ C², the magnet which has
attracted the armature will be short circuited so that the other magnet will then
preponderate and attract r, and will thus reverse by suitable reversing contacts the
direction of the current to be measured passing through the coil S, and so on.
The number of oscillations is registered by a suitable counter to which motion
s imparted either from the spindle of the meter or from the relay.
The work of the motor is consumed by the damping, so that neglecting losses
by friction etc., A (the work of the motor) is equal to D (the work of damping) or

page_text: that is, the number of oscillations z is directly proportional to the intensity of the
current, C1, C2, C being constants depending on the conditions of working. In
order to insure the working of the counter in each position and especially the
reversing of the current in the extreme positions, a small iron rod d Fig. 4 is
connected with the spindle and so formed that the torsion moments which the
alternations of the currents produce are compensated by the attraction of the
pins P P which act on the iron rod d in every position of the coi!.
This pull however can also be exercised by a magnet separately arranged and
instead of the rod d a magnetic needle or an electromagnet could be used.
In the latter case the desired action must be produced through an alternate
reversing of the poles either in the armature & or in the field magnets P P.
Further, the source of errors due to changes of temperature can be eliminated
by making the shunt resistance W Fig. 1 of the coil S of a material possessing
a relatively low coefficient of temperature, while the coil S and the damping bell E
are constructed with a material having a high coefficient of temperature (such as
copper).
In case of an elevation of temperature the damping action of the metallic
bell E becomes diminished, but at the same time the relation of the distribution of
current between the coil and the shunt resistance becomes changed, so that the
number of oscillations remains proportional to the consumption of current.
Dated this 11th day of June 1897.
ABEL & IMRAY,
Agents for the Applicant.
Improvements in or relating to Ampere-hour Electric Meters.
I, GEORG HUMMEL, of Dreimühlenstrasse 3, Munick, in the Kingdom of Bavaria,
Germany, 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 :-
This invention relates to an electric meter or counter for continuous currents,
having a coil traversed by the current, and arranged to oscillate in a constant
magnetic field, as I shall describe with reference to the drawings accompanying
my Provisional Specification.
Fig. 1 is an elevation partly in section of a meter according to this invention.
Fig. 2 is a sectional plan, Fig. 3 is an elevation partly in section and Fig. 4 is a
plan shewing a modification. M is a permanent magnet or a constant electromagnet
provided with two pole pieces cylindrically hollowed. A is a fixed armature.
The spindle a carries a coil S which is traversed by the main current, or a
fraction of it, while the metal bell E which oscillates in the strong magnetic field
acts for damping. For increasing the damping action a disc oscillating between
constant magnets can also be mounted on the spindle a, but this is not shown.
The construction of the new electric meter is generally similar to that of the
galvanometer of Deprez-d'Arsonval.
The mode of operation of the apparatus is as follows:-

page_text: The coil S traversed by the current to be measured is deflected in the constant
magnetic field. This deflection works a reversing commutator or a relay R Fig. 1,
whereby alternate reversing of the current at the end positions and consequently
an oscillating movement of the coil is caused to take place.
The arrangement and relative action of the meter and relay will be understood
on reference to Fig. 1. The magnetic windings m n of the relay R are connected
in series in a shunt circuit of the main circuit and both magnets are consequently
active during the vibrations of the coil S.
That magnet to which the relay armature 7 is nearest for the time being, holds it
stationary. On the magnet M are fixed insulated contact springs C¹, C², which are
connected respectively by a lead to the conductor connecting one of the relay
magnets to the main circuit, while an arm D fixed on the spindle a is connected to
the other ends of the windings of both electro-magnets R.
Thus, on the arm D coming in contact with one of the springs C¹ C², the magnet
which has attracted the armature », will be short circuited, so that the other magnet
will then preponderate and attract r, and will thus reverse by suitable reversing
contacts the direction of the current to be measured passing through the coil S, and
so on.
The number of oscillations is registered by a suitable counter to which motion is
imparted either from the spindle or the meter or from the relay.
The work of the motor is consumed by the damping, so that neglecting losses by
friction, etc., A the work of the motor, is equal to D the work of damping or A = D.
But A = J when C₁
€1,
is a constant and J is the intensity of the current.
D = c, Z where c₂ is a constant and Z the number of oscillations. Hence :
Also
that is the number of oscillations Z is directly proportional to the intensity of the
current C₁₂, C being constant depending on the conditions of working. In order
to insure the working of the counter in each position and especially the reversing of
the current in the extreme positions, a small iron rod d is connected with the spindle
and so formed that the torsion moments which the alternations of the currents
produce are compensated by the attraction of the pins P P which act on the iron
rod d in every position of the coil.
This pull however can also be exercised by a magnet separately arranged, and
instead of the rod d, a magnetic needle or an electro magnet could be used.
In the latter case the desired action must be produced through an alternate
reversing of the poles either in the armature d or in the field magnets P P.
Further, the source of errors due to changes of temperature can be eliminated by
making the shunt resistance W of the coil S of a material possessing a relatively
low coefficient of temperature, while the coil S and the damping bell E are con-
structed with a material having a high coefficient of temperature (such as copper).
In case of an elevation of temperature, the damping action of the metallic bell E
becomes diminished, but at the same time, the relation of the distribution of
current between the coil and the shunt resistance becomes changed, so that the
number of oscillations remains proportional to the consumption of current.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is
.
1. An ampere hour meter for continuous current wherein a coil, through which
the current to be measured passes, is caused, by the alternate reversal of the
current therein by suitable means, to oscillate in a constant magnetic field the said
oscillations being registered on a counter substantially as described.
2. In an empére hour meter such as is referred to in the first claim, the use of a
permanent magnet, in the field of which oscillates a coil through which the current

page_text: to be measured passes, and also a copper bell, moving with the said coil and
situated in a space between the poles of the magnet and a fixed armature,
substantially as described.
3. In an ampére hour meter such as is referred to in the first claim constructing
the moveable coil of a material having a high temperature coefficient, such as
copper wire, while the resistance in the main circuit is made of material having as
constant a resistance as possible for the purpose of reducing the influence of
variations of temperature, substantially as described.
4. In an ampére hour meter such as is referred in the first claim the use of an
iron rod fixed on the axis of the oscillating coil, the magnetic flux of which
rod is reversed at each reversal of the coil, and which oscillates between the poles
of a magnet for insuring the reliable action of the meter even with a small current,
substantially as described.
ABEL & IMRAY,
Agents for the Applicant.