Improvements in Electric Meters.
Year: 1892

page_text: Date of Application, 11th Nov., 1892
Complete Specification Left, 11th Aug., 1893—Accepted, 4th Nov., 1893
PROVISIONAL SPECIFICATION.
Improvements in Electric Meters.
I, CARL RAAB of Kaiserslautern, in the Empire of Germany, Electrician,
do hereby declare the nature of this invention to be as follows:-
This invention relates to electric meters comprising an electromotor which
actuates a counting train and an electro-dynamic damping or retarding device
which absorbs the surplus power of the motor. The motor and damper are usually
separate, and the invention has for its object to simplify the construction of the
meter by making the rotating armature a component part of both the motor and
the damping or retarding device, the armature revolving in a stationary magnetic
field set up by the current to be measured, the surplus power being neutralised by
a surrounding copper casing.
Reference is to be had to the accompanying drawings, forming part of this
Specification, wherein
Figure 1 shews a vertical section of one form of meter, on line c-d of Figure 2,
and Figure 2 is a horizontal section on line a-b of Figure 1.
Figures 3, 4, 5, 6, 7, 8, and 9, shew various modifications in sections..
A is the spindle of the revolving armature comprising the fine wire coils M³ to M'
carried by mica discs G and connected with a commutator C in the manner of the
Gramme armature. The armature coils M¹ to M' have a high resistance, are
constructed of many convolutions, and are placed in a shunt to the main circuit so
that they are traversed by a weak constant current. The armature revolves
between two fixed copper discs D and E and stationary solenoid coils F, H, J, K,
traversed by the current to be measured. The armature coils M' to M' are
switched into two parallel groups in the known way by the commutator C and
brushes B and B and the latter are so placed that the current of every coil of the
armature is commutated when it is situated centrally between the coils H, F, or
the coils K, J, so that the coils F, H, attract those armature coils that are repelled
by the coils K, J, and conversely the coils F and H repel those armature coils that
are attracted by the coils K, J, whereby the armature is revolved and actuates the
counting train Z with which its spindle is geared. When the armature is in the
position shewn in Figure 2 the coils F and H attract the armature coils M³, M6, M7,
and repel M2, M3, "M', whereas the coils K and J attract M2, M3, M, and
repel M, M, and M'. At this moment the armature coil M¹ is short circuited.
Directly the armature coils move, their lines of force generate unipolar currents in
the copper discs D and E whereby the surplus power of the motor remaining after
the friction of the mechanism has been overcome, is absorbed.
The modifications shewn in Figures 3 to 9 differ from the meter shewn in
Figures 1 and 2 chiefly in the mechanical arrangement of the motor and of the
electro-dynamic damping or retarding device. The armature in Figures 3 and 4
consists of crossed coils P¹ P'P' fixed to the spindle A by means of the mica disc G
and are connected with commutator C after the manner of the Hefner-Alteneck
armature. D, E, are the copper damping discs and NO the solenoid coils which
are traversed by the main current and set up the stationary magnetic field. Each
armature coil is short-circuited and its current commutated directly it arrives at the
centre of the magnetic field of the coils N, O. At the moment when the armature
is in the position shewn in Figure 4, its coil P¹ is short circuited while P2 and P³
are turned to the left by the coils N and O. Instead of the armature coils being in
a plane perpendicular to their axes of rotation, as in Figures 1 to 4, they may be
arranged as at R' to R', Figures 5 and 6, collectively in the form of a cylinder
concentric with the axis A to which they are rigidly connected by means of the

page_text: drum Q, the ends of the coils being connected to the commutator C after the
manner of the Gramme armature. The coils of the armature revolve between
the copper cylinders U, V, outside of which the coils Sand T traversed by the
main current are arranged in planes parallel to the axis A, the operation being
similar to that described in reference to Figures 1 and 2. In Figure 7 the armature
coils W', W2, W³, are formed by prolonging and bending down the coils P1, P2, P³,
of Figures 3 and 4 at right angles to the plane of the armature. The electric
motor is constituted on the same principle as that shewn in Figures 3 and, 4, the
stationary magnetic field being set up by means of coil Y the surplus power being
absorbed by the generation of unipolar currents by the bent down ends of the
armature coils W₁, W2, W³, rotating between the copper cylinders U and V. The
motor shewn in Figure 7 differs from those previously referred to, in that part only
of the armature which is opposite to the coil Y, acts as a component of the electric
motor, whilst the bent down part serves only for the electro-dynamic damping or
retarding device. The armature shewn in Figures 8 and 9 is an ordinary Gramme
armature consisting of fine wire coils L, L³, L³, L, L³, radial to the axis of
rotation. The armature is enclosed in the copper casing J for absorbing the
surplus power of the motor and which is in turn surrounded by the coil X which is
traversed by the main current. If the ordinary Hefner-Alteneck armature which
consists of crossed coils running both parallel and radial to the axis of rotation, be
substituted for the Gramme armature shewn in Figures 8 and 9, the coil X will be
unaltered.
Various alternative arrangements of the coils traversed by the main current may
be adopted, for instance with the meter shewn in Figures 1 and 2 the coils F, H, K, J,
may be switched parallel to one another or individually removed. The same
remark applies to the coils N and O shewn in Figures 3 and 4. With the meter
shewn in Figures 5 and 6 another thick wire coil can be arranged within the copper
cylinder V. Such modifications do not, however, involve any difference in principle
because all these coils are to be regarded as simple electric conductors by means of
which the main current generates the stationary magnetic field. Instead of using
copper for the discs or cylinders wherein the rotating armature generates unipolar
currents, other electric conductors may be used, for instance aluminium, and the
form may be varied instead of being discs and cylinders, and, furthermore, parts of
the copper casing, as for instance the disc D or E shewn in Figures 1 and 2, can
be removed as it is not necessary that the armature should be enclosed in copper
but only that its lines of force should cut fixed copper masses.
When employing the apparatus for measuring alternating currents only divided
copper masses within the influence of the armature and the fixed coils can be used
as both the armature coils on the one hand and the fixed coils on the other would
set up induction currents in the copper masses between them at the expense of the
unipolar currents. The generation of induction currents through the fixed coils
may be obviated in another way, viz. by entirely removing the copper masses from
the influence of the stationary coils. Such an arrangement is shewn in Figures 10
and 11 where the discs D, E, shewn in Figures 1 and 2 have large gaps a and a¹ so
that the coils F, H, and J, K, Figures 1 and 2 (which in this case have preferably
the altered form shewn in dotted lines in Figure 2) will have no inductive action on
"said discs. The same object will be fulfilled by dividing the copper masses by
simple slits and at same time the inductive capacity of the armature coils M¹ to M
will be checked. These slits are shewn in Figure 10. They may be disposed
peripherally as at b, b, or radially as at d, d¹, d², e, e¹, e². By this means it is
possible to entirely obviate the production of induction currents in the fixed copper
discs without sensibly interfering with the generation of unipolar currents.
If the
copper discs with gaps a a' shewn in Figures 10 and 11 are employed, those parts
of the armature situated opposite the gaps a a¹ only act as motor and the remaining
parts of the armature only for electro-dynamic damping or retarding. This double
function differs from that of the arrangement shewn in Figure 7 in that the
individual coils M₁ to M' serve alternately the purposes of motor and damper or

page_text: brake, whereas in Figure 7 a part of the armature W¹, W³, W.³, serves continuously
as motor and the other part as damper.
Dated this 11th day of November 1892.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Electric Meters.
I, CARL RAAB of Kaiserslautern, in the Empire of Germany, Electrician,
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 electric meters comprising an electro-motor which
actuates a counting train and an electro-dynamic damping or retarding device which
absorbs the surplus power of the motor.
The motor and damper are usually separate and the invention has for its object
to simplify the construction of the meter by making the rotating armature a com-
ponent part of both the motor and the damping or retarding device, the armature
revolving in a stationary magnetic field set up by the current to be measured, the
surplus power being neutralized by a surrounding copper casing.
Reference is to be had to the drawings accompanying my Provisional
Specification wherein
Figure 1 shews a vertical section of one form of meter, on line c-d of Figure 2,
and Figure 2 is a horizontal section, on line a-b of Figure 1.
Figures 3, 4, 5, 6, 7, 8, and 9, shew various modifications in sections.
A is the spindle of the revolving armature comprising the fine wire coils M
to M' carried by a disc G. of mica, paper, celluloid, or equivalent material,
and connected with a commutator C in the manner of the Gramme armature.
The armature coils M' to M' have a high resistance, are constructed
of many convolutions, and are placed in a shunt to the main circuit so
that they are traversed by a weak constant current. The armature revolves
between two fixed copper discs D and E and stationary solenoid coils F, H, J, K,
traversed by the current to be measured. The armature coils M¹ to M' are.
switched into two parallel groups in the known way by the commutator C and
brushes B1 and B2 and the latter are so placed that the current of every coil of the
armature is commutated when it is situated centrally between the coils H, F, or
the coils K, J, so that the coils F, H, attract those armature coils that are repelled
by the coils K, J, and conversely the coils F and H repel those armature coils that
are attracted by the coils K, J, whereby the armature is revolved and actuates the
counting train Z with which its spindle is geared. When the armature is in the
position shewn in Figure 2 the coils F and H attract the armature coils M5, M6, M7,
and repel M2, M3, M4, whereas the coils K and J attract M*, M³, M* and
repel M, M, and M. At this moment the armature coil M¹ is short-circuited.
Directly the armature coils move, their lines of force generate unipolar currents in
the copper discs D and E whereby the surplus power of the motor remaining after
the friction of the mechanism has been overcome, is absorbed.
The modifications shewn in Figures 3 to 9 differ from the meter shewn in
Figures 1 and 2 chiefly in the mechanical arrangement of the motor and of the
electro-dynamic damping or retarding device. The armature in Figures 3 and 4
consists of crossed coils P1, P2, P3, fixed to the spindle A by means of the disc G
of mica or equivalent material, and are connected with commutator C after the
manner of the Hefner-Alteneck armature. D, E, are the copper damping discs
and N, O, the solenoid coils which are traversed by the main current and set up.
the stationary magnetic field. Each armature coil is short-circuited and its current

page_text: commutated directly it arrives at the centre of the magnetic field of the coils N, O
At the moment when the armature is in the position shewn in Figure 4, its
coil P¹ is short-circuited, while P2 and P3 are turned to the left by the coils N
and O.
Instead of the armature coils being in a plane perpendicular to their axis of
rotation, as in Figures 1 to 4, they may be arranged as at R₁ to R',
Figures 5 and 6, collectively in the form of a cylinder concentric with the
axis A to which they are rigidly connected by means of the drum Q, the ends
of the coils being connected to the commutator C after the manner of the
Gramme armature. The coils of the armature revolve between the copper
cylinders U, V, outside of which the coils S and T traversed by the main
current are arranged in planes parallel to each other and to the axis A., the
operation being similar to that described in reference to Figures 1 and 2.
In Figure 7 the armature coils W1, W2, W³, are formed by prolonging and
bending down the coils P1, P2, P3, of Figures 3 and 4 at right angles to the
plane of the armature. The electric motor is constituted on the same principle
as that shewn in Figures 3 and 4, the stationary magnetic field being set up by
means of coil Y, the surplus power being absorbed by the generation of unipolar
currents by the bent down ends of the armature coils W¹, W, W³, rotating
between the copper cylinders U and V. The motor shewn in Figure 7 differs
from those previously referred to in that only the part of the armature which
is opposite to the coil Y acts as a component of the electric motor whilst the
bent down part serves only for the electro-dynamic damping or retarding.
The armature shewn in Figures 8 and 9 is an ordinary Gramme armature
consisting of fine wire coils L, L, L³, L, L, radial to the axis of rotation. The
armature is enclosed in the copper casing J for absorbing the surplus power of the
motor and which is in turn surrounded by the coil X which is traversed by the main
current. If the ordinary Hefner-Alteneck armature, which consists of crossed coils
running both parallel and radial to the axis of rotation, be substituted for the
Gramme armature shewn in Figures 8 and 9 the coil X will be unaltered.
Various alternative arrangements of the coils traversed by the main current may
be adopted, for instance with the meter shewn in Figures 1 and 2 the coils F, H,
K, J, may be switched parallel to one another or individually removed. The same
remark applies to the coils N and O shewn in Figures 3 and 4. With the meter
shewn in Figures 5 and 6 another thick wire coil can be arranged within the copper
cylinder V. Such modifications do not, however, involve any difference in principle
because all these coils are to be regarded as simple electric conductors by means of
which the main current generates the stationary magnetic field. Instead of using
copper for the discs or cylinders wherein the rotating armature generates unipolar
currents, other electric conductors may be used, for instance aluminium, and the
form may be varied instead of being discs and cylinders and, furthermore, parts of
the copper casing, as for instance the disc D or E shewn in Figures 1 and 2, can
be removed as it is not necessary that the armature should be enclosed in copper
but only that its lines of force should cut fixed copper masses.
When employing the apparatus for measuring alternating currents only divided
copper masses within the influence of the armature and the fixed coils can be used
as both the armature coils on the one hand and the fixed coils on the other would
set up induction currents in the copper masses between them at the expense of the
unipolar currents. The generation of induction currents through the fixed coils
may be obviated in another way, viz. by entirely removing the copper masses
from the influence of the stationary coils. Such an arrangement is shewn in
Figures 10 and 11 where the discs D E shewn in Figures. 1 and 2 have large gaps a
and a' so that the coils F, H, and J, K, Figures 1 and 2 (which in this case have,
preferably, the altered form shewn in dotted lines in Figure 2) will have no
inductive action on said discs. The same object will be fulfilled by dividing the
copper masses by simple slits and at same time the inductive capacity of the arma-
ture coils M¹ to M' will be checked. These slits are shewn in Figure 10. They

page_text: may be disposed peripherally as at 6 6¹ or radially as at d, d', d, e, e¹, e². By this
means it is possible to entirely obviate the production of induction currents in the
fixed copper discs without sensibly interfering with the generation of unipolar
currents. The same method of slitting may also be applied to the electro-dynamic
damping cylinders U, V, when used for alternate currents.
If the copper discs with gaps a a¹ shewn in Figures 10 and 11 are employed,
those parts of the armature situated opposite the gaps a a¹ only act as motor and
the remaining parts of the armature only for electro-dynamic damping or retarding.
This double function differs from that of the arrangement shewn in Figure 7 in
that the individual coils M¹ to M7 serve alternately the purposes of motor and
damper or brake, whereas in Figure 7 a part of the armature W', W², W³, serves
continuously as motor and the other part as damper.
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 I
claim is―
1. An electric meter devoid of iron wherein an armature placed in a shunt
and consisting only of coils, moves in a magnetic field generated by the passage
of the main current through fixed solenoids and in proximity to a metallic mass
or masses whose effect is to damp or retard the rotation of the armature, in the
manner specified.
2. An electric meter operating as specified under Clause 1 wherein the armature.
coils are of plane or cylindrical form and move in proximity to and parallel
with a metallic disc or cylinder, as specified.
3. An electric meter operating as specified in Clause 1 wherein the armature
revolves between metallic masses having the field solenoids behind or beyond them,
as specified.
4. An electric meter such as described, modified to adapt it for measuring
alternating currents, by removing the metallic masses from the neighborhood of
the main current coils, as specified.
5. An electric meter such as described, modified to adapt it for measuring
alternating currents, by slitting or otherwise dividing the metallic electro-dynamic
damping masses to avoid the induction of currents therein by the main coils, as
specified.
6. An electric meter operating as specified in Clause 1 and wherein the armature
coils are carried by a disc of mica or equivalent material, as specified.
Dated this 11th day of A1101181 1893.
Dated THIS ILR day of August. 1893.
C. RAAB,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.*