Improvements in Electric Meters.
Year: 1890

page_text: Date of Application, 18th Feb., 1890
Complete Specification Left, 18th Nov., 1890-Accepted, 10th Jan., 1891
PROVISIONAL SPECIFICATION.
Improvements in Electric Meters.
I, SEBASTIAN ZIANI DE FERRANTI, of 120 Fellows Road, Hampstead, in the
County of Middlesex, Electrician, do hereby declare the nature of this invention to be
as follows:-
In meters for recording alternating electric currents in which an armature or
spindle is caused to be rotated by the passage of the current I magnetically suspend
or partially suspend the arinature or spindle so as to reduce the friction on its pivots.
The suspending magnets used for this purpose 1 also in some cases use for producing
Foucault currents in a metallic disc carried by the spindle to retard the armature's
motion.
When the spindle is vertical and the armature an iron disc fixed permanent
magnets with their poles in proximity to the upper surface of the disc may be used.
Or a copper disc may be interposed between the poles and the armature or between
the poles and an iron disc on the spindle.
In the Wright meter (Patent No. 1480 in the year 1889) the armature may be in
the form of a cylindrical box lid and the disc at the top be used for magnetic suspen-
sion whilst the rim is used for giving rotation.
One magnet pole may be above the centre of the disc and the other pole be annular
and concentric with it-the pole piece above the centre may have a passage formed
vertically through it and the disc spindle be carried up through this passage.
Dated this 18th day of February 1890.
CARPMAEL & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in Electric Meters.
1, SEBASTIAN ZIANI DE FERBANTI, of 120 Fellows Road, Hampstead, in the County
of Middlesex, 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 :-
In meters for recording alternating electric currents in which an armature or
spindle is caused to be rotated by the passage of the current I magnetically suspend
or partially suspend the armature or spindle so as to reduce the friction on its pivots.
The suspending magnets used for this purpose I also in some cases use for producing
Foucault currents in a metallic disc carried by the spindle to retard the armature's
motion when it has been fairly started into rotation.
One great advantage of suspending or partially suspending the spindle in this
manner is that as the strength of the magnetic field is constantly varying with every
alternation of the current the spindle is kept in a state of tremor and this facilitates
the starting into rotation of the armature so that the meter will start with a current
of less strength than would otherwise be the case-that is to say it is equivalent to
gentle tapping of the meter.
When the spindle is vertical and the armature an iron disc fixed permanent
magnets with their poles in proximity to the upper surface of the disc may be used.
Or a copper disc may be interposed between the poles and the armature or between
the poles and an iron disc on the spindle.

page_text: In the Wright meter (Patent No. 1480 in the year 1889) the armature may be
in the form of a cylindrical box lid and the disc at the top be used for magnetic
suspension whilst the rim is used for giving rotation.
One magnet pole may be above the centre of the disc and the other pole be
annular and concentric with it-the pole piece above the centre may have a
passage formed vertically through it and the disc spindle be carried up through this
passage.
The drawing hereunto annexed shews diagram views of various ways of carrying
out my invention.
In the diagram view Figure 1-A is the armature spindle, B the armature-C an
iron disc carried by the spindle and D a fixed magnetic ring placed somewhat above
the iron disc. The spindle may rest at its lower end in a suitable bearing and be free
to rise a short distance in its upper bearing. The ring is shewn to have around it
two sets of coils. The two coils marked E have current passed through them for
magnetizing the ring, preferably they are in a shunt circuit and not in the main
circuit which is passing through the meter-the coils F F are closed circuits which
as described in the Specification of the before mentioned Patent will tend to produce
rotation of the disc when an alternating current is passed through the coils E
and so aid in giving rotation to the spindle. When the ring magnetized by the
passing of current through the coils E the spindle is lifted either until the disc is
nearly in a central position within the ring or until the upper end of the spindle
comes against the top of the upper bearing. In this way the spindle is shifted in
its bearings whenever current commences to pass and so the risk of the spindle
sticking in its bearings is avoided.
In the diagram view Figure 2 the electro magnet D is shown to be formed of an
iron ring of trough or U form in cross section with the magnetizing coils E contained
within the trough. In this case the spindle A passes up through the centre of the
ring. In this figure also the iron disc C is shewn as being built up together with the
armature B.
In the diagram view Figure 3 an iron disc C on the spindle A is shewn as being
acted upon by a fixed permanent magnet D. The magnet may be of sufficient strength
to uphold the spindle lightly into the upper bearing or to reduce the pressure of the
lower end of the spindle against the bottom bearing.
The diagram Figure 4 shews a similar arrangement except that the iron disc is
built up together with the armature in place of being detached from it..
The diagram Figure 5 shews another way of upholding an iron disc C by magnets D-
it also shews the disc as carrying a copper disc G so that as the speed of rotation-of
the spindle A increases it may be more and more retarded by Foucault currents set
up within the copper disc G.
The diagram view Figure 6 shews how a magnet may be used for suspending or
partially suspending the armature axis when the meter is so arranged that the armature
axis is in a horizontal position in place of a vertical one. In this case the spindle A
may have upon it two iron cylindrical enlargements to come below the two poles of
the magnet D as shown. In this way the spindle may readily be suspended to
such an extent as almost to balance the weight of the spindle and parts carried
by it.
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
1 claim is :-
· 1. Suspending or partially suspending the armature spindles of electric meters by
magnets.
2. An electric meter for recording the passage of alternating currents in which the
armature spindle is suspended or partially suspended by an electro magnet or magnets
energized by the alternating current.
3. An electric meter in which the armature spindle is suspended or partially

page_text: suspended by a magnet and in which the suspending magnet serves also to produce
Foucault currents in a metallic disc carried by the spindle.
4. The improvements in electric meters substantially as hereinbefore described.
Dated this 18th day of November 1890.
CARPMAEL & Co.,
Agents.