Improvements in or connected with Alternating Current Meters.
Year: 1897

page_text: Date of Application, 16th Feb., 1897-Accepted, 17th Apr., 1837
COMPLETE SPECIFICATION.
Improvements in or connected with Alternating Current Meters.
I, CARL RAAB of 18 Mainzerstrasse, Kaiserslautern, Rheinische 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 relates to alternating-current meters in which the variable shifting
of phase produced in the current consumers is compensated by a special shunt field,
in order to render the meters applicable also for induction circuits. The shunt
field may be adjusted to about 180° both free of induction and also by means of
transforming with the assistance of a shunt.
In the accompanying drawings, Figures I and II show an alternating-current
meter in which the motive force proceeds from two motors acting on a common
shaft.
Two metal discs A and B are fixed on a shaft C. Solenoids X and Y are
concentrically arranged and inserted in series in the main current circuit.
Solenoids XY' are also arranged concentrically as regards each other, but
displaced laterally relative to the solenoide X and Y, EO that the pairs of
solenoids X X and Y Y' can set in rotation the armature discs A and B.
coil X is connected in shunt with a choking coil D and the coil Y' with a bi-filar
resistance E in a second shunt.
The
So long as no self-induction arises in the circuit of the solenoids X and Y, the
coil X has a difference of phase as against the coil ✗', on account of the choking
coil D, of approximately 90°, whilst the coils Y Y on account of the bi-filar
resistance E have only a very moderate difference of phase. Thus in this case
the motive power is essentially afforded by the motor X, A, X. As soon, however,
as self-induction appears in the circuit of the coils X and Y by the switching on of
motors or for other reasons, a portion of the motive work passes over to the
motor Y, B, Y', until on the difference of phase between the coil X and the
coil X almost disappearing in consequence of self induction arising in the main
current circuit, the motive work is essentially produced by the motor Y, B, Y.
For the meter herein before described, the equation is therefore as follows:-
The smaller the difference of phase in the motor X, A, X', so much the more
work must the motor Y, B, Y', deliver, in order that the meter may show equal
indications with an inductive main current and a main current free of induction.
By rightly measuring off the bi-filar resistance E, the speed of the meter may be
so determined as to have for the same load an equal number of revolutions with an
inductive and an inductionless main current.
The shunt coils X', Y', are connected or arranged in opposite polarity in order
that they may revolve the armature in the same direction. As the pairs of
coils X, Y, and X', Y', stand axially to one another and the discs A and B are
arranged at little distance apart, the said pairs of coils form each a common
magnetic field.
Instead of the two armature discs A and B, a single one may be employed in
which case also one main current solenoid may also be omitted. Such a form of
construction is shown in Figures III and IV.
Above the armature disc O is arranged a solenoid P traversed by the main

page_text: current and beneath the same a solenoid Q and beneath that, concentric with the
latter, a solenoid R. In the arrangement shown in Figure 3, the solenoid Q lies in
a shunt in circuit with the choking coil G, whilst the coil R lies in a second sbunt
in circuit with a bi-filar resistance E. Instead of this latter, the solenoid Q may
be arranged in a shunt in circuit with the primary coil m of a transformer T, and
the solenoid R in series with the secondary coil n of this transformer in a circuit
closed on itself as shown in Figure IV.
The solenoid R serves in this case as assistant shunt which in combination with
the main current solenoid must deliver so much more work, the smaller becomes
the difference of phase between the solenoids P and Q in consequence of the
shifting of phase arising in the main current solenoid.
Figures V and VI show another form of construction in which the shunt
solenoids Q and R lie symmetrical to the main current-solenoid P. The current
connections may be effected either in the way shown in Figure III or in the way
shown in Figure IV. The shunt solenoids Q and R are in this case arranged for
similar polarity. The solenoids Q and R have a common magnetic circuit through
an iron core M, Figures V and VI. This construction of the meter has thus a
main current solenoid free from iron and two shunt solenoids with a common
magnetic circuit. Such an arrangement affords the great advantage that the
consumption of watts by the meter is reduced very considerably.
A mixed magnetic field may also be produced by providing each shunt itself
with iron, and by arranging both close side by side. If a complete magnetic
circuit be given in this case to the inductive shunt with a relatively weak saturation,
and an open iron core be provided for the inductionless shunt, that is to say, an
open magnetic field, the outside circuit lines of force of the inductionless shunt
run or pass over to the iron of the inductive shunt and complete their circuit in the
latter.
Such a construction is shown in Figures VII and VIII in which a metal
cylinder N serves as armature. A solenoid Q¹ forms the main current field and
an iron core S' carries the shunt coils D', D. A simple iron core R' with a shunt
coil is arranged close to the horseshoe iron S¹. Instead of arranging the coil R¹
on a separate iron core it may be also arranged on the iron core S', as shown in
Figure IX.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. An alternating-current meter having a metallic revoluble body, without a
supply of current, serving as an armature, a solenoid serving as a main current
field, and two turning shunt fields which are so arranged as to form a common
magnetic field, substantially as hereinbefore set forth.
2. An alternating-current meter of the kind described, consisting of a metallic
dise (), a main current solenoid (P) and two shunt fields (Q, R) lying con-
centrically to one another, of which one is in circuit with a choking coil (G) and
the other with a hi-filar resistance (E) substantially as described.
3. An alternating-current meter of the kind described, consisting of a metallic
disc (O), a main current solenoid (P) and two shunt fields (QR) arranged con-
centrically the one over the other, the one being arranged in a shunt in circuit with
the primary coil (m) of a transformer (T) and the other in an independent closed
circuit in series with the secondary coil (n) of said transformer, substantially as
described.
4. An alternating-current meter of the kind described, consisting of a metallio
disc (O), a main current solenoid and shunt solenoids (Q and R) arranged with
like polarity and connected by a common iron core (M), substantially as
described.
5. An alternating-current meter of the kind described, consisting of a metallic
cylinder (N¹) serving as an armature, a main current solenoid (Q¹) a shunt

page_text: coil (D', D) with a nearly closed iron core (S¹) and a shunt solenoid (R¹) arranged
close thereto with an open iron core substantially as described.
6. An alternating-current meter of the kind described, consisting of a metallic
cylinder (N¹) serving as armature, a main-current solenoid (Q'), a shunt (D', D')
with a nearly closed iron core (S¹) and a shunt coil (R') also on said core,.
substantially as described.
D
11.
121 1
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.