Method of and Means for Measuring the Work performed in a Rotary Phase Current System.
Year: 1898

page_text: Date of Application, 25th Feb., 1898
Complete Specification Left, 22nd Nov., 1898-Accepted, 25th Feb., 1899
FRUVIDIONAL SPECIFICATION.
Method of and Means for Measuring the Work performed in a
Rotary Phase Current System.
We, SIEMENS BROTHERS & CO. LIMITED, of 12, Queen Anne's Gate, Westminster,
S.W., Electrical Engineers, do hereby declare the nature of this invention (which
has been communicated to us from abroad by Siemens & Halske Aktien-Gesells-
chaft, Markgrafenstrasse 94, Berlin, S.W., Germany, Electrical Engineers) to be as
follows:-
This invention relates to a method of and means for measuring the work performed
by a rotary phase current system, which consists in the combination of two systems
each of which is adapted to measure the product of a strong current with a weak
current, the two weak current coils having currents passing through them that flow
from one of the three supply leads to a point connected by a star coupling therewith
through resistances as free as possible from induction, either the strong current
coils or the weak current coils of the two systems being made to bring into action
either the sums or the differences of the currents flowing in two different leads, or
their pressures.
In a rotary phase current system fed by three circuits the work transmitted at
certain moment is renresented by the formula
a
(1)
1
2
2
3
3
2
where A is the work, J, J, J, represent the currents in the three leads and V, V, V,
the pressures of these currents, relatively to zero.
The arrows on Figure 1 of the accompanying drawings shew the directions in
which the currents are considered positive.
The equation = J₁ + J₂ + J₁ always holds good, or :
where i, ii, are the weak currents, and w, w, w,
the resistances.
This equation gives, in assuming equality of the resistances w₁w, w,, the arrange-
ment of Frölich for measuring the work of a rotary phase current consisting in the
combination of three Watt meters with the strong currents J, J. J, and the weak
currents i, i, i..

page_text: This equation gives (for wx =
has the advantage over the
combined Watt meters.
e) the Aron-Behn-Eschenberg arrangement, which 5
Frölich, arrangement in that it only requires two
In the Frölich arrangement however two Watt meters may be made to suffice
if certain alterations be made, as will be hereinafter shewn.
For this purpose equation (4) is combined with the equation i, + i +i¸
whence :-
0 10
Figure 4 shews an arrangement for measuring according to this formula.
From equation (7) Ja can be eliminated according to the formula: J₁ + J + J₁ = 0,
obtaining the equation
(9.) A
==
[J, (ww) + J¸ w¸] i¸ + [J₂ (w₁ + w₂) + J, W₂] V¸
1
which only contains the four currents J, J, i, i..
Figure 2 shews a corresponding measuring arrangement.
For w ==
ww, of formula (10) the coils A and D must have exactly double
the action on the weak current coils that the coils B and C have.
If this be not the case, the system can nevertheless be made to indicate the
work correctly according to formula (9) by a suitable adjustment of w₁ w₂
and w
Formula (10) can also be written as follows:-
or if i, i, i₁ =0₁:
(12) A = [J, (i, — i¸) + J¸ (i − i¸)] w₁.
-
The work can be measured by both formulæ if the two weak current coils be
each provided with two separate windings, while with the above described
arrangements the strong current coils consist of two separate windings.
Figure 3 shews an arrangement according to formula (12).

page_text: Method of and Means for Measuring the Work performed in a
Rotary Phase Current System.
We, SIEMENS BROTHERS & CO. LIMITED, of 12, Queen Anne's Gate, Westminster,
S.W., Electrical Engineers, do hereby declare the nature of this invention (which
has been communicated to us from abroad by Siemens & Halske Aktien-
Gesellschaft, Markgrafenstrasse 94, Berlin, S. W., Germany, Electrical Engineers),
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 a method of and means for measuring the work performed
by a rotary phase current system, which consists in the combination of two systems
each of which is adapted to measure the product of a strong current with a weak
current, the two weak current coils having currents passing through them that
flow from one of the three supply leads to a point connected by a star coupling
therewith through resistances as free as possible from induction, either the strong
current coils or the weak current coils of the two systems being made to bring into
action either the sums or the differences of the currents flowing in two different
leads, or their pressures.
In a rotary phase current system fed by three circuits the work transmitted at a
certain moment is represented by the formula :-
2
where A is the work, J, J. J, represent the currents in the three leads and
0 V, V, V, the pressures of these currents, relatively to zero.
The arrows on Fig. 1 of the drawings accompanying our Provisional Specification
shew the directions in which the currents are considered positive.
The equation O
=
J₁ + J¸ + J¸ always holds good, or :-
where i, i, i, are the weak currents, and w, w, w, the resistances.
This equation gives, in assuming equality of the resistances u, w₂ w₁, the
arrangement of Frölich for measuring the work of a rotary phase current consisting
in the combination of three Watt meters with the strong currents J, J, J, and the
weak currents i, i, i₁..
If in the equation (3) V =V then:

page_text: =
This equation gives (for wx wy) the Aron-Behn-Eschenberg arrangement,
which has the advantage over the Frölich arrangement in that it only requires two
combined Watt meters.
In the Frölich arrangement however two Watt meters may be made to suffice if
certain alterations be made, as will be hereinafter shewn.
=
For this purpose equation (4) is combined with the equation i₁ + i + 1, 0
whence:-
1
which only contains the four currents
Figure 2 shews a corresponding measuring arrangement.
For w == w of formula (10) the coils A and D must have exactly double
the action on the weak current coils that the coils B and C have.
If this be not the case, the system can nevertheless be made to indicate the
work correctly according to formula (9) by a suitable adjustment of w, w, and w₁.
Formula (10) can also be written as follows:-
-
(12) A = [J, (i, – į¸) + J¸ i¸ − i )] w₁.
The work can be measured by both formulæ if the two weak current coils be
each provided with two separate windings, while with the above described
arrangements the strong current coils consist of two separate windings.
Fig. 3 shews an arrangement according to formula (12).
An arrangement of the measuring apparatus can also be employed for correctly
measuring the work by means of a single Watt meter, according to the above
formulæ 9 and 10 as we will describe with reference to the accompanying drawing.
As in the previously described arrangements the weak current coils S1 S2 are
mechanically coupled together on one and the same axis, the two strong current
coils A B are placed opposite these in such manner that, in order to comply with
the formula, each strong current spool acts simultaneously upon the two weak
current or measuring spools but so that, for example, the action of coil A on S¹
is twice as strong as on S2, while that of B is twice as strong on S² as on S¹.
Thus according to formula 10 currents are passed from two of the leads
respectively through A and B, while the weak currents, branched from the corre-
sponding strong currents pass in the known manner through the resistances w, w,
(as free as possible from induction) and are connected at one point with the third
weak current.
If the positions of the strong current coils A B are such that their action on the
one weak current coil is not double that exercised on the other then, according to
formula (9) the resistances w, w, w, may be suitably adjusted so that the apparatus
will still indicate correctly.

page_text: The principles herein set forth may be applied to any apparatus for measuring
electrical energy in which the reaction of a strong current coil on a weak current
coil exerts a turning moment, or a deviating force, proportional to the energy to be
measured, such as electro-dynamometers, induction balances and motors provided
with counting or recording mechanism.
Thus the two weak current coils may be mounted on the same axis which, when
no current is passing through the coils, is kept in the zero position by a spring or a
counter-weight. The strong current coils may be arranged in such manner that
each weak current coil is in the field of one of the strong current coils; or in such
manner that the two strong current coils are asymmetrically placed with regard to
the weak current coils, so that each of the latter is in a portion of the field of each
strong current coil, such portions differing in intensity, weak current coil No. 1,
being influenced by strong current coil No. 1, for example, twice as strongly as by
strong current coil No. 2, and weak current coil No. 2 being influenced by strong
current coil No. 2, twice as strongly as by strong current coil No. 1. Any known
means of integration may serve to sum up the deviations of the axis from the zero
position and thus to measure the electrical energy consumed.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, we declare that what we
claim is:
1. In the method of measuring the work performed by a rotary phase current
system, wherein a combination of two systems each of which is adapted to measure
the product of a strong current with a weak current is so arranged that the two
weak current coils have currents passing through them that flow respectively from
one of the three supply leads to a point connected by a star coupling therewith
through resistances as free as possible from induction; the arrangement whereby
either the strong current coils or the weak current coils of the two systems are
made to bring into action either the sums or the differences of the currents
flowing in two different leads, or of their pressures, substantially as described.
2. In the method of measuring the work performed by a rotary phase current
system wherein two weak current coils have currents passing through them that
flow respectively from one of the three supply leads to a point connected thereto by
a star coupling through resistances as free as possible from induction, the
arrangement of a system of two weak current coils and two strong current coils in
such manner that each strong current coil influences both weak current coils but
in different degree, substantially as described.
Dated this 22nd day of November 1898
ABEL & IMRAY,
Agents for the Applicants.