Improvements in Electro-dynamic Relays for Use on Telephone and Telegraph Lines.
Year: 1898

page_text: Date of Application, 11th Nov., 1898
Complete Specification Left, 11th Aug., 1899-Accepted, 30th Sept.,
1899
PROVISIONAL SPECIFICATION,
Improvements in Electro-dynamic Relays for Use on Telephone and
Telegraph Lines.
SIDNEY GEORGE BROWN, Van Buren, Poole Road, Bournemouth, in the County
of Hants, Electrical Engineer, do hereby declare the nature of this invention to
be as follows:-
This invention relates to improvements in electro-dynamic relays for use
principally on telephone or telegraph lines, the object being to obtain a
tinuous amplification of the arrival signalling currents.
con-
The amplified current to be used to operate telephone or telegraph instruments
or other apparatus whereby more powerfull effects could be obtained or a
smaller volumn of current would be required to perform the same work.
The instrument consists of a field magnet, the magnetic flux through which
divides at a part of the circuit into at least two portions, the quantity of flux
through each portion being determined by controlling electrical conditions.
It also consists of a rotating armature, preferably slotted or tunnelled near the
periphery of the iron discs, and wound with copper wire, joined up to a com-
mutator, or it may consist of a plain disc or drum made of iron or other metal
as in the unipolar type of dynamo.
The following is a description of a relay constructed according to my inven-
tion, which might be used for various purposes of telegraphy.
The armature A tunnelled & wound with wire, runs between two pairs of
The flux from the
magnetic poles B and C with preferably small clearance.
outside magnetic circuit, which circuit may be permanent or electro-magnetic,
divides between and enters two poles, that are not opposite each other, passes
through the armature and leaves by the other two alternative poles at the
bottom. Those portions of the magnetic circuit immidiately joining the pole
pieces, pass through auxiliary coils of wire, the currents through which it is
desired to copy and magnify, by induced currents in the armature.
When the armature is in rapid rotation and the auxiliary coils not excited
no current need be induced in the armature conductors for though the two pairs
of pole pieces B and C may be strongly magnitized yet they may be equal in
strength, and would be sending their flux through the armatures in opposite
directions.
If therefore a current is sent through the auxiliary coils, the two poles B
would be strengthened and the two poles C' would be weakened resulting in a
current being induced in one direction in the armature or vice versa if the order
of the poles are reversed. By this arrangement the magnetism in a small mass
of iron need be varied, while if the diminution of flux in one pair of poles is
counteracted by an equal gain in the other pair the flux need not vary at all in
the rest of the outside circuit. If the relay is to be used for magnifying tele-
phone currents I should preferably use the unipolar form of dynamo con-
struction, making the various electrical connections with the rotating disc or
drum by means of mercury.
In one form of construction the flux from the magnetic circuit would divide
at one part of the circuit into two portions, one by way of, say, a short-circuit
and the other passing through the armature disc or drum.

page_text: An auxiliary coil or coils of wire would be again placed so as to controll when
excited the amount of flux passing through the short-circuit or armature, result-
ing in a variation in the induced voltage in the armature, while if the flux
diminished in one portion as much as it gained in the other portion, the flux
need not vary at all through the other parts of the magnetic circuit.
This form of construction enables the length of the circuit through which the
flux is forced to vary to be made as compact as possible. In this case the fluctua-
tion of current through the auxiliary controlling coils may be copied and
magnified by currents induced in the rapidly rotating armature.
As the induced voltage would be of low pressure it might be advisable to pass
the current from the armature a few times round an iron transformer core,
round which again a secondary coil of wire is wound, so that the voltage may be
increased before being employed in the outside circuit.
Dated this 10th day of November 1898.
Improvements in Electro-dynamic Relays for Use on Telephone and
Telegraph Lines.
1, SIDNEY GEORGE BROWN, of Van Buren, Poole Road, Bournemouth, in the
County of Hants, 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 improvements in electro-dynamic relays for use prin-
cipally on telephone or telegraph lines, and has for its object the continuous
amplification of the arrival signalling currents, whereby more powerful effects
are obtained, or, in other words, a volume of current smaller than hitherto
necessary is required to operate the recording or other instruments.
According to my invention I induce a current in the relay circuit by means of
a dynamo and provide means whereby any current induced in the armature of
said dynamo (which armature form part of the relay circuit), is prevented from
affecting the recording or other instruments in the relay circuit except when the
arrival currents.
According to one form of construction the magnetic flux through the field
magnets of the dynamo divides at a part of the circuit into two, or some multiple
of two, portions. The arrival currents are led through auxiliary coils of wire
wound on the magnetic pole pieces, and the quantity of magnetic flux in each
of the aforesaid portions is determined by controlling the electrical conditions
in such manner that when no arrival current is received, no current is induced
in the armature which forms part of the relay circuit.
In order that my invention may be clearly understood and readily carried into
effect I will proceed to describe the same more fully with reference to the accom-
panying drawings in which:-->
Figure 1 is a side view of the relay apparatus.
Figure 2 is a plan of the armature and its magnetic pole pieces.
Figures 3 and 4 are plan views respectively of the top and bottom bars of the
apparatus with the magnetic pole pieces attached to them.
Figure 5 is a diagram showing the winding of the magnetic pole pieces herein-
after referred to.
A is the armature which is rotated by any suitable mechanical means. B, B,
are the electro magnets having pole pieces N, N and S, S, the former of which
are of North polarity and the latter of South polarity. These pole pieces are

page_text: arranged diagonally with relation to one another as shown in Figure 2. C is a
battery or equivalent means for exciting the magnets up to a critical point. Dis
a bent iron strip or bar for connecting all the North poles of the magnets and E
is a similar bent iron strip or bar for connecting all the South poles of the
magnets. The line conductor F is connected to auxiliary coils wound round the
magnetic pole pieces which coils are connected to earth by the conductor F¹.
The armature A has slots or tunnels a a near its periphery to receive the wire
with which it is wound, in order that it may run with but small clearance between
the magnetic pole pieces. G, G is the relay circuit.
It is obvious that the magnets B, B, may be permanent magnets or may be
excited by an alternating or by a periodic current if preferred.
The magnetic flux from the magnets BB divides between and enters the two
magnetic pole pieces N, N, passes through the armature A, and leaves by the
magnetic pole pieces S, S.
When the armature is in rapid rotation and the auxiliary coils are not excited,
no current is induced in the armature, because although the two pairs of pole
pieces may be strongly magnetized yet they are equal in strength and are wound
so as to direct their magnetic flux through the armature in opposite directions.
These auxiliary coils are so wound however, that when the arrival current from
the line passes through them, one pair of the pole pieces is strengthened and
the other pair weakened. This results in a current being induced in the arma-
ture, which passes to the relay circuit G, G. By this arrangement the magnetism
in a small mass of iron only need be varied, for if the diminution of flux in
one pair of the magnetic pole pieces is counteracted by an equal gain in the
other pair of magnetic pole pieces, the magnetic flux need not vary at all in
the rest of the outside circuit, in order to obtain an induced current.
It is obvious that means, other than those described above may be employed
for neutralizing any current induced by the initial excitation of the magnets,
without departing from my invention. For instance:-the armature A may
run between only one pair of magnetic pole pieces, the neutralizing of any
current induced when no current is received from the main line, being effected
by outside means such as a condenser or transformer placed in series in the
relay circuit.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
-
1. Electro-dynamic relay apparatus in which the arrival currents are caused
to vary the magnetic conditions of said apparatus in such manner that an induced
current passes through the relay circuit, only when the said arrival currents are
received, for the purpose specified.
2. In electro-dynamic relay apparatus of the kind herein before referred to,
the combination with the pole pieces of auxiliary coils through which the line
currents pass substantially as described and for the purpose specified.
3. Electro-dynamic relay apparatus constructed arranged and operating sub-
stantially as described with reference to the accompanying drawings for the
purpose specified.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.