Improvements in or relating to Watt-meters.
Year: 1895

page_text: Date of Application, 18th Nov., 1895-Accepted, 11th Apr., 1896
COMPLETE SPECIFICATION.
Improvements in or relating to Watt-meters.
I GEORG HUMMEL of Dreimühlenstrasse 3, Munich, Bavaria in the Empire of
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 has for its object to so establish the relation between the number
of revolutions and expenditure or consumption of "watts in motor-counters, that
each is directly proportional to the other, and so that the watt-consumption or
expenditure can be read off directly from the counting mechanism.
In the accompanying drawings,
Figure 1 is a diagram illustrating the relation of watt-consumption to "number
of revolutions" in certain instances hereinafter referred to.
Figures 2 and 3 are diagrams illustrating alternative modes of winding the
improved counter-motor.
Figure 4 is a diagram illustrating the construction of an adjustable inductive
resistance coil hereinafter referred to, forming part of this invention.
Figure 5 is a diagram illustrating my improved counter-motor and its
appurtenances included in an electric-light circuit.
Figure 6 is a side elevation and
Figure 7 a plan of a detail of my improved counter-motor.
In general, the combination of a "Ferraris"-motor and a damper or deadening
disc gives a relation between " watt-consumption" and "number of revolutions,
which is shown in Fig. 1 in the accompanying drawings, by the curve A¹ (the
scale 1, 2, 3, 4 being a scale of revolutions and the scale 100, 200, being a scale of
watts) whereas in reality it should be represented by a right line A 3.
or error can however be corrected, as hereinafter appears.
This defect
In Fig. 2, E represents the magnet-frame of my improved counter-motor,
HH the principal winding or coil through which the current flows that is to be
measured; further W is an endless coil, forming a closed circuit.
If, through the primary wire-winding or coil H H (the principal current-winding
in the counter) an alternating current be sent, there arise losses of current in that
secondary circuit W which are approximately proportional to the square of the
strength of the current in the principal winding H H.
A similar effect is obtained, when as appears in Fig. 3 instead of employing a
secondary winding or coil one applies to the main winding H H a shunt Was
shown, approximately free from induction which forms a conductor for the noxious
currents which ordinarily would produce the difference between the effect
represented by the curve A¹ as compared with the curve A 2.
The resistance of these short circuits W or the number of their windings or
convolutions is so measured and adjusted that the loss therein attains a magnitude
by which the curve A¹ is caused to pass over into the right-line A 2, so that the
indications of the counting apparatus are proportional to the watt-consumption.
Hitherto this curve A 2 has been used for calculating the watt-consumption and
for this purpose it has been necessary to multiply the indications of the counter as
recorded by such a line A 2 by a constant for each apparatus.
In order to avoid even this calculation an adjustable inductive resistance coil w
joined up in tension with a shunt-winding nn of the counter motor as represented
in Fig. 5. This enables the resistance of the shunt-winding n and therewith the

page_text: number of revolutions of the counter-motor to be so regulated that the multiplica-
tion by the constant is rendered needless, and that the watt-consumption can be
read direct from the counting apparatus, as represented in the right line A. 3 in
Fig. 1.
Essentially this correction is carried out in the following manner (see
Fig. 4);-
Two symmetrically formed lamellated iron cores E¹ and E2 round which the
shunt-winding wire wis coiled in tension, are placed side by side in opposition to
each other. On the sides there are projections or lugs a tapped to receive two set-
screws by means of which the two halves (or cores) can be drawn closer together
or removed farther apart from one another.
By drawing the two cores nearer together the induction-action and effect is
increased and consequently less current passes through the shunt n; and vice versa,
the contrary effect is produced by increasing their distance apart.
In this manner I am enabled within certain limits so to regulate the shunt-
winding current and therewith the number of revolutions of the motor, that with a
certain translation-ratio between the motor and the counting mechanism, the
watt-consumption can be directly read off the latter.
By means of this shunt-current which is constant after the resistance is once
adjusted a small traction-effort is applied to the motor-counters, by means whereof
the counter, even if there is no current in the windings H H or W, has a tendency
to rotate. In order to prevent any such counter from running on in the absence
of a principal current, a small piece of iron e is secured, as shown in Fig. 6, to the
copper disc K by which a magnetic retardation or stoppage is effected, inasmuch as
the permanent magnet M attracts it and can retain it as long as there is no current
in the windings H H.
By turning the iron piece e round on a pivot at m this stop-motion can be so
regulated, that the counter when there is not any current in the chief conductor
will be stopped by the magnet M but so that with the smallest supply of current
to the main, the power of attraction of the magnet M on the soft iron e is
overcome.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what
claim is;-
1. In alternate-current motor-counters the employment of an endless closed
winding or coil W which runs parallel to the principal winding or coil H H for the
purpose of obtaining a certain proportionality between the number of revolutions
and the watt-consumption substantially as described.
2. In alternate-current motor-counters, the employment of an adjustable
inductive resistance joined up in series with shunt-coils of the counter for the
purpose of giving to the proportionality mentioned in Claim I such a value that
the indications of the counting mechanism directly correspond to the watt-
consumption.
3. In motor-counters the employment of a magnetic moderating or stopping
device on the rotary part for the purpose of preventing any rotation thereof in
the absence of a principal current.
Dated this 18th day of November 1895.
BOULT & WADE,
Agents for the Applicant.