Improvements in Electric Meters.
Year: 1896

page_text: Comelada
Date of Application, 13th Jan. 1896
4006
Accented
04 at Nove
1966
PROVISIONAL SPECIFICATION.
Improvements in Electric Meters.
I, CARL RAAB of 19 Mainzer Strasse Berlin in the Kingdom of Prussia,
Engineer do hereby declare the nature of this invention.to be as follows:-
The improved meter for alternating currents consists of a revoluble metal disc
which is influenced by two rotary magnetic fields. One of these two magnetic
fields is excited by means of two solenoids through which passes the current to be
measured. The other magnetic field which differs about 90° in phase from the first
field is excited by means of two horse-shoe electro-magnets with many windings
connected to the source of current to be measured whereby the said electro-magnets
simultaneously act as brakes. This meter is characterized essentially by the facts
that the aforesaid revoluble disc acting as motor armature is intersected in two
places by the lines of force of the horse-shoe electro-magnets and that the main
current spools as well as the armature disc are placed immediately opposite to and
also in near proximity to the electro-magnet poles.
In the new meter revolving forces of equal direction appear at two points of the
armature disc. The main current causes circular currents in the metal plate a.
considerable portion of which currents reaches the horse-shoe magnets and
propagates itself in the same with a main current circuit free from induction.
field is displaced 90°, whilst the fields excited from the windings on the horse-shoe
magnets possess a phase displacement also amounting to about 90°.
This
When the main current circuit is displaced in phase there occurs also in the
circular current field a displacement which can rise to 180° as a maximum. In the
horse-shoe magnets there then arises a mixed field whose phase displacement
approaches 90° so that the error caused by self induction in the consuming current
circuit is entirely corrected. Experiment shews that this result is attained as the
curve shewing the law of the meter indications is practically the same whether or
not the current consuming circuit possesses self-induction. The above mentioned.
circumstance furnishes the improved meter in itself already with a considerable
advantage over the construction hitherto known. Moveover by the above described
method of construction an extraordinarily favourably working motor meter is
produced in which the consumption of energy in secondary circuit and the resistance.
of the main current conductors can be very materially reduced with sufficiently
large measuring capacity and fully satisfactory checking.
The constructional details of the apparatus are capable of very considerable
modification also if the motor power should be double the free half of the disc
could also be provided with magnetic fields by means of solenoids and electro-magnets
and thereby unite the thus produced electro-magnetic systems under one single
system.
...
ليود
1
1000
W. P. THOMPSON & Co.,
31, High Holborn, London, W.C., Patent Agents for the Applicant.

page_text: Improvements in Electric meters.
I, CARL RAAB, of 19, Mainzer, Strasse, Berlin, in the Kingdom of Prussia,
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 :-
+
The present invention relates to alternate current meters having à metallic disc
serving as a motor armature, set in rotation by means of main current solenoids
free from iron in combination with shunt electromagnets and in which the solenoids
with their axes perpendicular to the armature disc are arranged in the immediate
neighbourhood both of the armature and of the free poles of the electro-magnets.
In the accompanying drawings:-
Figure 1 is an elevation and
Figure 2 is a plan of one form of my improved meter.
Figure 3 is a diagram bereinafter explained.
Figures 4 to 7 show modified forms of meters, constructed according to my
invention.
Like letters of reference denote similar parts throughout the drawings.
Referring to Figures 1 and 2 A is the revoluble disc placed under the influence
of two revolving magnetic fields. One of these two magnetic fields is excited by
the current to be measured by means of the two solenoids B and C included in the
main current circuit I. The other magnetic field displaced nearly 90° in phase
from the first mentioned field is excited through two horse-shoe magnets D, E
with many windings connected to the source of the current to be measured through
the shunt connection i, the electro-magnets D, E at the same time act as a brake.
The new meter is characterised essentially by having the motor armature A crossed
by the lines of force of the electromagnets D, E and by having the main current
spools B, C arranged both immediately opposite the armature and also in immediate
neighbourhood of the electromagnets.
The windings D' E' are so connected to the current conductors that they induce
apparently equal polarities in the magnets D and E. They create in the said
magnets one magnetic field which possesses as against the other magnetic field a
phase displacement of about 90°. The other magnetic field (main current field)
arises through the solenoids B, C which are placed between the pole ends of the
horse shoe magnets. The lines of force due to the shunt magnets penetrate the
armature at two points in opposite directions. They create therefore in combination
with B and C at the two points of penetration two turning moments, which act to
rotate the disc in the same direction. The main current excites rotary currents in
the armature A and a considerable part of the field due to these passes into the
horse shoe magnets D, E and propagates itself in the same. When the main
current circuit is free from induction this field is displaced 90° whilst the fields
excited by the windings D' and E' possess phase displacement only approaching
to 90°. With a phase displacement of the main current circuit there appears also
nevertheless in the revolving current field a displacement which may amount to
nearly 180° as its maximum. In the magnets D, E there then occurs a mixed field,
whose phase displacement rises to 90° so that the error caused by self induction in
the consuming current.circuit is completely corrected. That this is the case is
illustrated by the diagram shewn in Figure 3 which are curves having for ordinates
the number of revolutions of the arinature in any given period of time and for
abscissæ the energy consumed in the main current circuit during that time, the
simple dots shew the law of the meter when the current consuming circuit is free
from induction, the encircled dots shew the law with a self inductive consuming
current circuit having the phase displacements usual in motors.

page_text: This circumstance gives the new meter in itself already a great advantage over the
constructions hitherto known. The described construction produces an extraordinary
favourably working motor in which the consumption of energy in the shunt and the
resistance of the main current conductor can be very materially reduced the meter:
having at the same time a sufficiently great range of measurement and a perfectly.
satisfactory braking action.
In Figures 4 and 5 a modification is illustrated in which the main current
solenoids are arranged partly between the pole of the horse shoe magnets. Figure 4
is a section on the line a-b in Figure 5. Figure 5 is a plan' of the meter...
As already indicated in the construction shewn in Figures 1 and 2 solenoids B, C
as well as the electrò magnets D, E are placed symmetrically to one another. The
disc A serving as motor armature is crossed by the lines of the electromagnets D, E.
The main current spools B, C stand immediately opposite the armature disc A and
excite in said armature currents which possess a phase displacement of 90° the
magnetic field due to these currents is partially equalised in the iron core of the
shunt magnet whereby the phase displacement of the mixed shunt field is brought
to 90°. The meter shown in Figures 1 and 2 gives correct indications with either
inductive or non-inductive current consuming circuits as long as the difference of
potentials remains within given limits: In the modifications illustrated in
Figures 4 and 5 however the superior limit is incréased and. this results from the.
fact that the main current solenoids B, C are partially inserted in the electro-
magnets. Hence the main current field is still more approached at two places.to.
the circuit of the shunt lines of force and the lines of force of the currents.induced
in the armature A by the main current field will penetrate so. much more easily
into the horse shoe magnets.
"
T.
According to the modification set forth in the Figures 4 and 5. the diameter, and
consequently the weight of the armature will be considerably smaller. The scope
of measurement therefore is on the one hand increased while on the other hand any
stopping mechanism for the transport of the meter may be dispensed with:
Moreover the construction of the meter is rendered very simple. The solenoids do
not require to be specially fastened but may be simply jammed tightly between the
horse shoe magnets. If it be desired to double the motor power of the motor
meters illustrated in Figures 1 and 2 and 4 and 5 the free halves of the disc A may
also be provided with magnetic fields and the consequently requisite electromagnetic
systems be united in a single one. Another alteration could be, made by crossing
the disc A only at one point by lines of force or the electromagnets D, E for
instance by the prolongation of D and E in the direction of their lamellation, 80
that two limbs must project beyond the disc A and can be united into a single
piece of iron. Moreover it would also be possible to place such an electromagnet
radially to the disc A whereby then the solenoids B, C would be arranged sideways
to the free poles for the creation of the turning moment. Finally the disc-shaped.
armature might also be replaced by a cylindrical revolving body, and the whole
mechanism be adapted to the piece thus altered.
Figure 6 is a sectional elevation, and Figure 7 is a sectional plan of such a
meter.
The armature consists of the metallic cylinder M which is carried by the
revoluble axis. On the outer wall of the cylinder M the electromagnet E and the
solenoid C lying between the free poles of the same are arranged in the manner
shewn in the drawing. On the inner wall of the cylinder M is provided the
electromagnet D with the solenoid Blying between its free poles. The spools D¹ D'
and EE are in the shant circuit and serve for the exciting of the electro-
magnets D, E which in combination with the solenoids B and C actuated by the
main current set the armature M in rotation. The diameter of the solenoids B, C
is considerably smaller than that of the armature M in order that for the purpose
of obtaining concordant results with consuming current circuits free from induction
and such as are inductive, the solenoids may be brought sufficiently near to the
walls of the armature. As now for the same purpose the limbs of the horse shoe

page_text: magnets must. approach closely to the solenoids, the, two poles of the horse shoe
magnet are arranged in the manner shewn in the drawing. The central plane
common to both, limbs. of the, magnet, stands perpendicular to the axis of the
armature. The poles of the electromagnet stand as in the above described meters
exactly opposite one another, in order that as small a resistance as possible shall
be offered to the shunt lines of force crossing the armature. The electromagnet D
placed in the interior of the armature M is formed in the shape of a horse shoe on
the one hand for the purpose of. obtaining room for the shunt winding and on the
other hand in order that the lines of force of the solenoids B and C may not
penetrate in too great quantity in the iron core of the shunt. Though the described
arrangement is obtained that exactly a sufficient part of the lines of force induced
by the main current passes through the horse shoe magnets so that the number of
revolutions is proportional to the energy employed.
"Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A meter for use, with alternating currents having a metallic disc serving as
motor armature set in rotation by the action of main current solenoids free from
iron in combination with shunt electromagnets and characterised by the arrangement.
of the solenoids with the axes perpendicular to the armature disc and in the
immediate neighbourhood both of the armature and of the free poles of the
electromagnets, substantially as described.
2. The modification of the improved meter wherein the main solenoids are
partly surrounded by the poles of the electromagnets substantially as described.
3. The modification of the improved meter wherein the disc shaped armature is
substituted by a cylindrical armature on the outer wall of which as well as on the
inner wall horse shoe magnets are arranged with poles sloped off corresponding to
the cylindrical surface, substantially as described.
Dated the 26th day of September 1896.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Agents.