Improvements in Electricity Meters.
Year: 1890

page_text: Date of Application, 18th Nov., 1890-Accepted, 17th Jan. 1591
UNTIME OF POLYALION.
Improvements in Electricity Meters.
We EUGEN HARTMANN and WUNIBALD BRAUN both of Bockenheim, Frankfurt-
on-Maine in the Empire of Germany Electrical Engineers do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertaine i in and by the following statement :—
According to this invention the quantity of electricity passing in a conductor is
measured and registered by employing an Ampère meter worked by a solenoid having
a core of special construction as hereinafter described and causing the amount of
leflection of the pointer of this motor to produce a corresponding movement of a
registering apparatus by means of an electrically operated device such as an electro
magnet which at given intervals of time moves the pointer of the Ampère meter back
This movement being transmitted to the registering mechanism produces
an intermittent motion of the latter corresponding in extent to the amplitude of the
eflection or vibration of the pointer of the Ampère meter. The electro magnet or the
like is excited or caused to act on the pointer at the proper times by means of clock-
work which is automatically wound up by the movement of the armature which inter-
mittently produces the return of the Ampère indicator to zero.
to zero.
And in order that our said invention may be fully understood we shall now proceed
more particularly to describe the same and for that purpose shall refer to th severa
figures on the annexed sheets of drawings the same numerals and letters of reference
indicating corresponding parts in all the figures.
Figure 1 of the accompanying drawings represents in front elevation an example of
an apparatus constructed according to this invention.
Figuro represents the apparatus in end elevation and
Figures 3 and 3 relate to the core of the solenoid.
Figures 4 and 5 illustrate a modification and ictail hereinafter referred to.
In constructing an electric meter operating according to this invention it is
necessary in order to obtain correct indications to employ an Ampère meter in which
the movement or amount of deflection of the pointer is in direct proportion to the
current of electricity flowing through the meter. In order to obtain this relation
between the current and the movement of the pointer the Ampère meter is constructed
with a solenoid S Figures 1 and 2 which exerts attraction on a hollow core K of
soft iron the sectional area of which is greater near the onds than at the middle.
This core illustrated separately in Figure 3A is obtained by taking a flat piece of soft
sheet iron and cutting it out as represented in Figure 3 for example or to suen a shape
that when rolled up or wrapped upon a rod k (Figure 3) of non-magnetic material it
produces a hollow roll or mass of metal of the required tapering form as represented
in Figure 3A for example.
By commencing the rolling operation at the narrow ends of the sheet the taper or
inequality in the thickness of metal may be formed on the interior. In this case the
core presents a cylindrical form externally as represented in Figure 4 in place of the
externally tapering form represented in Figure 3A.
An iron core thus constructed with a sheet of soft iron properly cut out to shape in
accordance with the form of the solenoid enables a truly proportionate action to be
obtained and owing to its advantageous division is very little influenced by the
residual magnetism. The axis of the cylindrical solenoid may be either straight or
curved and the movement of the pointer can he either rectilinear or circular.
The pointer of the Ampère meter may receive a circular movement directly from a
solenoid and core of corresponding shape or a rectilinear movement of the solenoid
core may be converted into a rotary or angular movement of the pointer by means of
lever or drum for example. The force which the solenoid bas to overcome in moving

page_text: the pointer of the Ampère meter may be obtained either by a spring or by a weight
or by a weight and a spring acting in combination.
According to the arrangement illustrated in Figures 1 and 2 the core K of the
solenoid S is suspended from the extremity of a spring B and is connected at its lower
end to an arm (shown in dotted lines in Figure 1) on the arbor of the pointer 2 of
an Ampère meter provided with a spring Facting by torsion in opposition to the force
exerted by the solenoid S. Any other suitable combination of springs or weights or
both may be employed to perform the function of the spring F. For example the
solenoid core may be suspended from a helical spring at its upper end and be supported
by a blade spring at its lower end as represented in Figure 4.
The spindle or arbor 3 of the Ampère meter carries a pulley Ron which is coiled a
cord connected to the armature 5 of an electro magnet E wound with coils of high
resistance and provided with a damping or retarding device such as the piston and
cylinder 6 for example. An arm carrying a pawl is fixed on the arhor 3 so as to
move with the pointer 2 and drives a ratchet wheel which can rotate upon the artor.
This ratchet wheel drives a train of wheels working the pointers of i registering
apparatus 7 (Figure 1).
The clockwork which causes the current to pass in the coils of the electro magnet E
at regular intervals is illustrated in Figures 1 and 5 and is driven by a spring which
is automatically wound up by the action of the said electro magnet by means of a
pawl and ratchet arrangement worked by a cord 8 connected to the armature 5.
This clockwork being regulated by an ordinary balance 9 drives a cam or tappet 10
which acts on a contact making lever 11. This lever, once in every revolution of the
tappet or cam 10, makes contact at c so as to put the electro magnet E into circuit
through the conductors 12.
The action of the apparatus is as follows. The current to be metered flows in
the coils of the solenoid S and the pointer 2 of the Ampère meter is deflected to an
extent directly proportionate to the quantity of the current. The clock work having
been wound up the rotation of the cam 10 causes contact to be made at ani the
electro magnet being now excited attracts its armature 5 and overcoming the power
of the solenoid S rotates the arbor 3 of the Ampère meter so as to bring the pointer
back to zero and at the same time winds up the spring of the clockwork. The
movement of the arbor 3 is transmitted by means of the pawl to the ratchet wheel
and to the registering apparatus 7 whose pointer or pointers are consequently rotated
to an extent corresponding to the amplitude of the angular movement or displacement
of the pointer 2 of the Ampère meter. The clock work being caused to rotate without
intermission then breaks contact at e and the armature of the magnet E is caused to
return to the position indicated in the drawing by the action of a counter spring 13.
The arbor 3 and pointer 2 of the Ampère meter are now again rotated by the action
of the solenoid S to an extent proportionate to the current. In case the quantity of
the current increases or liminishes the amplitude of this rotary motion or vibration
or deflection of the pointer 2 increases or diminishes to a corresponding extent and
the pointer 2 and arbor 3 of the Ampère meter consequently describe a larger or
smaller angular movement when the magnet E brings the poinser back to zero.
The
movement of the registering mechanisin being dependent on the movement of this
pointer and arbor the quantity of current passing is thus enabled to be accurately
recorded by the said mechanism.
The clockwork may be of any suitable description and may be regulated either by a
pendulum or by a balance wheel and driven either by a weight or by a spring. A
balance wheel regulator and driving spring are preferably employed in order to
economise space. In order that the clockwork may not run down completely when
the current ceases it is provided with a small lever so arranged that at a certain
moment it comes gently into contact with the balance wheel and thus arrests the
movement of the latter but when the current is reestablished in the meter this lever is
moved out of contact with the balance which thereupon resumes its motion. The
said lever is also caused to maintain the circuit of the electro maguet closed when the
current is switched off so that when the apparatus is put in circuit again the current

page_text: is enabled to pass immediately in the coils of the said electro magnet independently
of the contact c which at this moment is open.
C
This arrangement is illustrated in Figures 1 and 5. As the clockwork runs down
a lever 14 is lowered but so long as the current passes the clockwork is not allowed
to run down sufficiently to enable the lever 14 to make contact with a contact
spring 15 owing to the lever being raised by the intermittent action of the electro
magnet which is excited at the requisite periods by the automatic closing of the
contact at c.
When no current passes in the meter owing to its being switched out of circuit for
example no electricity can circulate in the coils of the electro magnet which then
ceases to wind up the clockwork and the latter runs down until the lever 14 comes in
contact with the spring 15 as represented in Figure 5 and by the same movement
engages with the brake lever T and causes the latter to stop the balance 9. The
contact at 14-15 is connected with the contact at c or with the electro magnet and
is so arranged as to enable the current to pass in the coils of the electro magnet E
directly the apparatus is put into circuit thereby winding up the clockwork and
releasing the balance.
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 :-
1. In an electric meter working with a solenoid and Ampère meter the arrangement
of a core composed of sheet iron cut out to such a shape that when formed into a roll
it constitutes a hollow core of tapering or conical shape having the effect of obtaining
a direct proportion between the quantity of current and the movement of the pointer
of the Ampère meter substantially as hereinbefore described with reference to the
accompanying drawings.
2. An electro magnet or equivalent device placed in circuit at definite intervals by
means of clockwork and moving the current indicator or pointer of the Ampère meter
from its indicating position back to zero and at the same time winding up the clock-
work in combination with registering mehanism whose motion is dependent on that
of the Ampère meter, substantially as hereinbefore described with reference to the
accompanying drawings.
3. In clockwork with a balance regulator the employment of a brake or stopping
mechanism which after the spring barrel or motor has driven the clockwork to a
certain extent without being wound up acts upon the balance and stops the clockwork
automatically substantially as herein before described with reference to Figures 4 and 5
of the accompanying drawings.
4. The general combination and arrangement of parts constituting improved
apparatus for measuring electric currents substantially as hereinbefore described.
13
101 ↑
1000
J. H. JOHNSON & Co.,
Agents.