Improvements in Moveable Zero Relays.
Year: 1898

page_text: Date of Application, 28th June, 1898-Accepted, 30th July, 1898
Improvements in Moveable Zero Relays.
We, EUGENE ATHANASE FRANCOIS ARNAUD, and CLAUDE ANATOLE ANTOINE
GUSTAVE GANTES, both of Alger (Algerie), France, Telegraph Clerks, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
In proportion as the length of a submarine cable increases, it is known that
the electrical impulsions received, cause at the point at which they are collected,
phenomena which are due to the electrical condensation the importance of which
increases with the length of the cable.
It follows that if the curves described by the siphon recorder are examined
irregular ups and downs will be observed and consequently a continual diver-
gence of the median line or zero.
Fig. 1, represents the signal
66
understand" at the departure or as it would
be seen on the siphon recorder on a line or cable without electrical capacity.
Fig. 2 represents the same signal received at the extremity of a cable having
a certain capacity.
It will be seen that between the third dot and the dash the electric zero has
shifted so that an ordinary relay having fixed stops could not collect each emis-
sion when the currents are interchanged.
But if by a device we force the stops to shift in the same direction and over
the same space as the electrical zero in question they will always be symetrically
situated with regard to the zero and consequently able to collect all the emissions.
Our investigations on this subject have enabled us to make relays with move-
able zeros which we describe further on taking as a basis the consideration that
the bobbin made use of by the siphon recorder but divested of fibres and pivoting
on a rigid axis is the fittest organ for faithfully registering the electric state of
a cable.
The peculiar disposition of the shunted bobbins and the mobility of the stops
form the special feature of our invention.
In an intense magnetic field let us place two bobbins A and B (Fig. 3) of 500 ohms
resistance each and mounted in a special manner which shall be described
further on.
Let us fix to the bobbin A a metallic index terminating by a contact and to
the bobbin B a like index but terminating by two stops isolated from each other.
The latter bobbin B is to be placed at a certain distance from the two poles,
that is, in such a position that without removing it from the action of the magnet
it is as much as possible under the influence of the most widespread lines of
force.
Their respective position as shown by the drawing is such that the index of A
oscillates between the stops of B.
Contrary to the mode of suspension adopted for the siphon recorder we make
those bobbins pivot on their axis without their being influenced by any adverse
fibre, so that they will always note the highest summits of the currents and will
be subject to their influence only, whatever their intensity or direction may be.
[Price 8d.]

page_text: The entrance of each bobbin is bound to the cable C, the outlet to the earth T.
The currents of the cable will fork, therefore, at A and B and if the coiling
of the wires is such that they oscillate in an inverse direction, index and stops
will always go towards each other.
If the forces of impulsion were equal, if in other terms, the resistances of the
two bobbins were equal we should only have reduced by half the course of an
ordinary relay with fixed stops and whilst the electric zero of the cable would
have changed its place, stop and index would adhere for a certain moment as
long as the charge that forced them against each other remained
even if a contrary charge should intervene. We could not therefore collect in
time the currents we wish to make use of.
We have thought of reducing at will the sensitiveness of the bobbin B holding
the stops so as to reduce to a minimum its oscillatory movement by the intro-
duction of a shunt $.
It follows that between the cable and the bobbin B we shall introduce at the
same time a compensatory resistance R c so as to maintain a constant regimen
in the bobbin A.
But if by the application of the law of multiplied resistances we have dimin-
ished the resistance of the bobbin B on the one hand and the resistance of the
whole of the two circuits CAT and CBT, on the other we shall have raised the
potential between the points C and T without the multiplying action of A being
modified. It follows that the energy of A will preponderate and that under
the influence of a current, the index holding the stops of B, will be always drawn
after the index of A.
The free stop will have approached the primitive zero, it may even have gone
beyond it, it will certainly have followed the change of place made by the electric
zero as we have already said, by an equal change of place.
To give a fixed idea, let us consider the armature in three different positions
(Figs. 4, 5 and 6).
10. Fig. 4. Ideal position of rest, the cable is in a neutral state. This state
may be represented by the line A¹ which really represents the zero.
20. Fig. 5. The positive current intervenes. The two armatures meet at the
point O during the first period of charge, which may be represented by the full
curve B¹.
30. Fig. 6. This current attains its highest summit.
The index of A which must indicate it, has drawn the armature holding the
stops which in going over has drawn the free stop nearer to the dotted primitive
zero.
The curve C represents this.
It is evident that whatever emission follows the first, the system will still be
placed symetrically as regards the new electric zero of the cable.
We have still to consider the moveable zero relay from another standpoint.
We have said at the beginning that the electrical condensation increased
with the length of the cable.
It follows that from a certain length the index of A will just be strong enough
to change its place but will not have force enough to overcome the inertia of the
bobbin B.
We can reduce this inertia to nothing by inverting the direction of the
current of B that is by favoring the movement of the stops in the same direction
as that of the index of A.
The working will be regulated then simply, as in the first disposition by the
shunt which introduces into bobbin B an energy equal to the inertia.
Fig. 7 shows the central piece M carrying two bobbins and also the entire
apparatus.
Each bobbin pivots by the bottom on an agate cup P fixed to the screw V
and by the top by means of a small hole made in the index into which enters a
very fine brass needle which can go down into the hole by means of a screw V

page_text: Two very light ebonite plates E E' (Fig. 9) joined by two aluminium rods LL¹
guarantee by their adherence to the bobbin the movements of the aluminium
index I I.
Each index I and I' has at its longest part a triangular form to avoid vibra-
tions.
We think it unnecessary to mention here the weight and dimensions, these
particulars being rather of interest to the constructor.
The electric connections are made by the terminals D D and D' D' for the
entrance and outlet of the bobbins and B2 B2 and 13 for the local circuit (Figs. 7
and 8).
P is one of the two branches of a powerful magnet made of a bunch of steel
rods.
Their polar extremities are terminated by soft iron caps which by the shape
indicated by Fig. 8 form the poles in P2 and P³ which we shall call the mag-
netic field of the bobbin A.
The poles P and P5 which we shall call secondary poles constitute the mag-
netic field of the bobbin B.
The distance between the two bobbins A and B corresponds to that of the
magnetic fields P2 and P3 and P and P5.
The central piece M fixes upon the wooden socle S by means of the screws V V₁
and this socle is supported by the cast iron or copper brackets Cresting by means
of the collar C3 on the branches of the magnet which form the uprights.
It may be added that in the grooved part of each bobbin there is a piece of
soft iron F which is fixed to the frame and this piece is intended to increase the
intensity of the magnetic field.
This piece, moreover, is made use of in the siphon recorder.
As to the shunt & and the compensating resistance Rc they will find their
place on the socle S, the boxes containing them will be circular and provided
with a slider.
think
Without settling the form, which also interests the constructor, we
that a single box will suffice, if it is constructed so that the action of a single
handle introduces at the same time the shunt and the corresponding compen-
sating resistance.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:―
In telegraphic relays, shunted bobbins pivoting on a central axis which bobbins
produce the mobility of the stops by means of which moveable zero relays are
obtained.