Improvements in Electric Meters.
Year: 1896

page_text: Date of Application, 8th July, 1896
Complete Specification Left, 29th Mar., 1897-Accepted, 1st May, 1897
[Communicated from abroad by SIEMENS AND HALSKE, of Berlin, in the German
Empire, Electrical Engineers.]
Improvements in Electric Meters.
We, SIEMENS BROTHERS & Co. LIMITED, of 12 Queen Anne's Gate,.
Westminster in the County of London, Electrical Engineers, do hereby declare
the nature of this invention to be as follows:-
This invention relates to an electric meter operating on the known principle of
Deprez-d'Arsonval, but so arranged that the indicating pointer is free to be
deflected more or less according to the current affecting it, and, having taken its
position of deflection, it is moved back to zero by apparatus which at the same
time moves the gearing of a totalising counter an amount corresponding with the
deflection.
The deflection and it registration are caused to recur at intervals by the
reciprocating movements of a balance wheel, urged in the one direction by the
attraction of an electro magnet on an armature fixed on the wheel, and urged in
the opposite direction by a spiral spring.
The movements of the wheel effect not only the return of the pointer and the
registration of its deflection as above stated, but also make and break the contacts
by which currents pass to the meter coils and to those of the electromagnet which
drives the wheel.
The contacts are arranged with delicate adjustments by which excess movements.
of the wheel are prevented, and certain contacts are provided for periodical short.
circuiting of the meter coils, so as to correct errors due to hysteresis.
OLT.1- 1000
ABEL & IMRAY,
Agents for the Applicants.
We, SIEMENS BROTHERS AND COMPANY, LIMITED, of 12, Queen Anne's Gate,
Westminster, in the County of Lendon, Electrical Engineers, 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 an electric meter operating on the known principal of
Deprez-d'Arsonval, but so arranged that the indicating pointer is free to be
deflected more or less according to the current affecting it, and, having taken its
position of deflection, it is moved back to zero by apparatus which at the same
time moves the gearing of a totalising counter an amount corresponding with the
deflection.

page_text: The deflection and its registration are caused to recür at intervals by the
reciprocating movements of a balance wheel, urged in the one direction by the
attraction of an electro-magnet on an armature fixed on the wheel, and urged in
the opposite direction by a spiral spring.
The movements of the wheel effect not only the return of the pointer and the
registration of its deflection as above stated, but also make and break the contacts
by which currents pass to the meter coils and to those of the electromagnet which
drives the wheel.
The contacts are arranged with delicate adjustments by which excess movements
of the wheel are prevented, and certain contacts are provided for periodical short-
circuiting of the meter coils so as to correct errors due to hysteresis.
The said apparatus consists of the following parts :-
An electrical indicating pointer and scale: means of transmitting the deflections
of the pointer to a counter; driving mechanism for that purpose; and means of
correcting errors due to hysteresis.
Reférring to the accompanying drawings,
Figure 1 is a section and Figure 2 is an end view of the electrical indicating
apparatus, Figures 3, 4, and 5 are front views shewing the pointer and driving
mechanism in various positions.
Figure 6 is a front view of the contacts for the driving mechanism.
Figures 7 and 8 shew details hereinafter referred to.
The apparatus consists of an ammeter, volt-meter, or watt-meter, according to the
principle of Déprez-d'Arsonval, in which the field of force is produced by means of
magnets or electro-magnets m, m2, and a current or tension bobbin J is arranged
in a rotatable manner within the same, and around a fixed iron core K situated
within the bobbin. The movable bobbin J is supplied with current through two
flexible spiral springs S S (Figures 1 and 7) which are fixed on the axle of the
bobbin, with connections to the ends of the bobbin and are insulated from each
other.
The movable bobbin J carries à pointer Z which can oscillate freely over a
graduated scale T and is dead-beat in its action.
This pointer after being deflected is returned to the zero position by means of a
bent. rod B the movements of which sum up the deflections of the pointer by means
of a counting wheel R having its edge finely toothed, which is turned by a pawl
spring to the zero point of the scale, and actuates the wheels of a counter by a
pinion N. The bent rod B is pivotted about the axle a' at p' p, and is moved by
means of a driving mechanism periodically. This bent rod is extended beyond its
two pivots at p¹ and p², and carries at one end above p' a counterweight G, its
extension above carries an adjustable stop Q and a light pawl spring f¹ having
its end situated a little above the periphery of the counting wheel R.
A spring stop arranged on a bracket D which is fixed to the axle of the
pointer shares all the movements of the pointer. When is pressed against the
end of by the movement of the bent rod B, the end of the spring is caused
to engage in the teeth of the counting wheel R and as the stop Q prevents the
spring from being farther deflected the movement of the pointer to the zero
point of the scale causes the counting wheel R to be rotated to the same extent
and thus actuates the counter.
After the pointer reaches the zero point of the scale T, the bent rod B swings
back (Figure 4) and thus releases the pointer Z, which then at once moves into
the position: determined by the current passing and is then ready for a fresh
registration.
"The device for driving the bent rod B, consists of an oscillating fly wheel P,
having on it a tappet S which moves the bent rod B one way, a spring which
always draws the rod B'against the tappet S causing its return movement. The
rod B is thus moved over the whole extent of the scale by the fly wheel P, and
then is returned by the spring up to a stop H.
The ly wheel P runs in ball
bearings L, and has attached to its axis à spiral

page_text: spring like that of the balance wheel of a chronometer which allows of its
oscillation. An armature A fixed to the wheel is periodically attracted by the
electro magnet E when contact is made by the following device:
To an insulated clamp J¹ is fixed a contact spring f the lower part of which is
forked. The two limbs of this fork carry platinum contacts c which in their
position of rest bear against the contact screws of the forked ends of an
insulated stop J. The contact spring is acted upon by lever W pivotted to a
strap O fixed on the axle a of the oscillating fly wheel P and urged by the
spring into such a position that on the rotation of the axle a", the nose a
strikes against the end of spring f. When the fly wheel axle a² rotates in the
direction opposite; to that of the hand of a clock, the nose n' strikes against the
end of the spring faud raises it away from the contacts c¹ and until the nose n'
has moved past, when the springs fly back into their position of rest against the
contacts c¹³.
When now the wheel P moves back in the same direction as the hands of a
clock, the nose n' again strikes the spring f whereby the end off projecting
beyond the contact being comparatively weak becomes bent, allowing a to pass
it, the contacts cc remain unbroken.
In order to prevent the oscillations of the escape wheel P from becoming too
great the arm W is provided with three noses. n n² n³ and can turn about the
pivot a, but is held in position by the pressure of the bent spring upon the
nose n. During the oscillation of the wheel P, the contacts is effected by
the nose n', through the spring for a certain period until the are of oscillation
has reached a certain limit. When the limit is exceeded, the nose a strikes
against the stop a, the tipping lever W moves into the position shewn in dotted
lines in Figure 6, so that a can, pass the spring without acting upon the
contacts cc. On the return of the wheel, W is moved back again into the
previous position by the stop y acting on the nose a which is bent into a different
plane from that of the nose n.
The spring has its one end fixed to the wheel P and its other end connected
to the rod B (Figures 3, 4, and 5) which at the zero point of the scale meets a
stop H, and is thus prevented from being carried any further by the wheel P.
The wheel continuing to rotate, without the rod B, in the same direction, strains
the spring By adjusting the tension of the spring by turning an arm U the
movement of the wheel P can be determined as desired.
In order to correct the error due to hysteresis on return of the pointer to zero
by means of the contact plates on the rod B the field coils m² m² are short
circuited at the points d' and d and the current hobbin J is short circuited at e
and whilst in front of the tension coils there is included a resistance w¹ behind
which the short-circuiting takes place.
The movable coil is connected in a well-known manner to a resistance at the
ends of which the difference of potential and consequently the current strength
present in the resistance is measured.
In consequence of the short circuiting above mentioned there is produced an
almost total demagnetisation (regard being had to the remanent magnetism) and
the course of the curve of magnetisation is such that the curve always rises from
this point, so that magnetisation takes place only from below in an upward
direction, and thus the fault of hysteresis is practically obviated. The apparatus
operates in this manner with a rising current only, not with a rising and failing
current.
In place of the coils situated in the magnetic field, and provided with a fixed
iron cylinder according to the well-known arrangement of Deprez-d'Arsonval,
other arrangements having iron armatures movable in the field might be employed,
so long as the points dd, el e correspond or coincide entirely as regards
connection, with the points indicated in Figure 8. The operation of the pairs of
contacts dd, el e² or of one of them for the purpose of short circuiting or cutting
out wire coils, can be effected in another way, for example, by means of the

page_text: Pointer or any other suitable moving part or mechanism; also the short
circuiting or the interruption of the current coils or of the tension coils might be
effected separately.
The motion of the lever W on the fly wheel axle a² in combination with the
spring contact may be applied to operate a contact on a special contact
spring f, by means of which short-circuiting is effected of the tension coils m¹ m²
in front of which there is further included a resistance w¹ arranged outside of the
short-circuit branch.
The course of the current in the apparatus is as follows:—
TENSION BOBBIN m² m².
The current passes from the positive terminal through the included resistance wo',
through the lead 1 to the contact J³. If contact e³ is open (Figure 2), the current
passes from J³ to the coils of the tension bobbins m' m² and after flowing through
the same it returns through the lead 1 to the negative terminal.
If contact is closed (Figure 6), the field magnet coils m¹ m² are short "
circuited, and the current passes from J³ to the spring f, contact c³, to the
terminal J and through the lead 1 back to the negative terminal.
CURRENT COIL J.
The current passes from the negative terminal through lead 2 to the spiral
spring S insulated from the pointer axle a' to the pointer carrier Dani thence
through the coils of the current bobbin J and to the axle a', whence it Hows to
the spiral spring S2, through the same and through the lead 2 to a separate positive
terminal.
2. OPERATION OF THE CLOCKWORK.
The current passes from the positive terminal through the included resistance w²
and thence through the lead 3 to the contact J².
If the contacts cscs are open (Figure 6) the current passes from the contact
piece J to the coils of the electro-magnets E and thence to the contact J¹ whence
it returns through the lead 1 to the negative terminal.
If contacts cs are closed (Figure 2) the current passes from the contact J
(the electro-magnet coils E being short circuited) through the contacts s¹¹²² to
the spring and to the contact J' and thence back through the lead 1 to the
negative terminal.
Having now particularly described and ascertained of our said invention
and in what manner the same is to be performed, we declare that what we
claim is :-
1. An electrical measuring and recording apparatus so arranged that the pointer
is absolutely free while it is deflected by the current and is connected to the
recording apparatus only during its return to zero, the movement of the
counting mechanism being effected by a spring pawl which is made to engage a
counting wheel when moved at intervals against the pointer, substantially as
described.
2. In the apparatus above referred to moving the carrier for the spring pawl by
a fly wheel moved in the one direction by an electro-magnet, in the other by a
spiral spring, substantially as described.
3. In the apparatus above referred to, the contact mechanism for the driving of
the fly-wheel, comprising a contact lever, carrier spring and stop arranged and
operating, substantially as described.

page_text: 4. In the contact mechanism referred to in the preceding claim a tipping-
contact lever arranged to correct amplitude of oscillation of the fly wheel
substantially as described.
5. In the electric meter referred to in Claim 1, the combination of the wheel P,.
the rod B, its stop H, and the adjustable spring substantially as and for the
purpose set forth.
6. In. apparatus such as is referred to in Claim 1, obviating errors due to.
hysteresis by periodically short-circuiting the coils, substantially as described.
Dated this 29th day of March 1897.
ABEL & IMRAY,
Agents for the Applicants.