IMPROVED METHOD OF APPLYING VARIABLE RESISTANCE TO ELECTRIC " CURRENTS WITHOUT COMMITATOR
Year: 1883

page_text: LETTERS PATENT to Lucien Gaulard of Langham Street and John Dixon
Gibbs of Bury Street both in the County of Middlesex for an Invention of
IMPROVED METHOD OF APPLYING VARIABLE RESISTANCE TO ELECTRIC
"
CURRENTS WITHOUT COMMITATOR
"
PROVISIONAL SPECIFICATION left by the said Lucien Gaulard and John
Dixon Gibbs at the Office of the Commissioners of Patents on the
24th February 1883.
LUCIEN GAULARD of Langham Street and JOHN DIXON GIBBS of Bury Street
both in the County of Middlesex " IMPROVED METHOD OF APPLYING VARIABLE
RESISTANCE TO ELECTRIC CURRENTS WITHOUT COMMUTATOR,"
The construction of this apparatus is based on the following principles :-
When a circuit arranged as in a solenoid and traversed by an alternating current
is caused to enter the interior of a coil, it gives rise in the wire of this coil to an
induced current.-This current being in the opposite direction to the first current,
which originated it, opposes a resistance to the latter if the circuit of the induced
coil remains open.
This being established, the apparatus is constructed in the
following manner :-
A fine copper wire covered with silk, and with disconnected extremities, is
wound upon a cylinder of wood or cardboard, the diameter of which varies
according to the power it is desired to give to the apparatus, which diameter for
example may be one centimetre with a length of four centimetres-In the axis of
this coil and fixed to one of its extremities, is placed a small cylinder of soft iron,
say five millimetres in diameter, upon which is formed a screw thread.-Upon
another cylinder composed of wood or cardboard and say five millimetres in
diameter are wound two superposed series of coils of copper wire, also insulated,
and the extremities of which are connected at the upper part of this cylinder with

page_text: two binding screws or terminals.-This cylinder so formed is capable of sliding
between the internal sides of the coil firstly described upon the screw thread on
the rod arranged on its axis.
In the annexed drawing B is the external coil, C the internal coil, the two
extremities t. t. of which are connected with the circuit of the current to which the
resistance is to be opposed. F is the rod of soft iron.
From the foregoing description, it will be readily understood that the resistance
opposed to the current passing in the circuit C will be in proportion to the extent
to which this circuit is caused to enter the interior of the coil B
SPECIFICATION in pursuance-of-the-conditions of the Letters Patent filed
by the said Lucien Gaulard and John Dixon Gibbs in the Great Seal Patent
Office on the 24th August 1883.
ナ
LUCIEN GAULARD of Langham Street; and JOHN DIXON GIBBS of Bury Street
-both in the County of Middlesex, "IMPROVED METHOD OF APPLYING VARIABLE
RESISTANCE TO ELECTRIC CURRENTS WITHOUT COMMUTATOR
">
The construction of this apparatus is based on the following principles:-When
-a circuit, arranged as in a solenoid and traversed by an alternating-current, - is.
caused to enter the interior of a coil, it gives rise in the wire of this coil to an
induced current.-This current being in the opposite direction to the first current
which originated it, opposes a resistance to the latter if the circuit of the induced
coil remains open. This being established the apparatus is constructed in the
following manner:-A fine copper wire covered with silk and with disconnected
extremities, is wound upon a cylinder of wood or cardboard, the diameter of which
varies according to the power it is desired to give to the apparatus, which diameter
for example may be one centimetre, with a length of four centimetres.-In the
axis of this coil, and fixed to one of its extremities, is placed a small cylinder of
soft iron, say five millimeters in diameter, upon which is formed a screw thread-
Upon another cylinder composed of wood or cardboard and say five millimeters in
diameter, are wound two superposed series of coils of copper wire also insulated,
and, and the extremities of which are connected at the upper part of this cylinder with
two binding screws or terminals. This cylinder so formed is capable of sliding
between the internal sides of the coil firstly described upon the screw thread on
the rod arranged on its axis.
In the annexed Drawing-B is the external coil.-C, the internal coil, the two
extremities t. t. of which are connected with the circuit of the current to which the
resistance is to be opposed-F is the rod of soft iron.
From the foregoing description, it will be readily understood that the resistance
opposed to the current passing in the circuit C will be in proportion to the extent
to which this circuit is caused to enter the interior of the coil B.
Having now particularly described and ascertained the nature and object of the

page_text: said Invention, and in what manner the same is to be performed or carried out in
practice, we hereby declare that we claim as our Invention the new application of
the action produced by a solenoid having its ends disconnected and open, which
surrounds more or less another solenoid, through which an electric current is
passing, for the construction of variable resistances without commutation or
contacts substantially as hereinbefore set forth and described and as illustrated by
the accompanying Drawing.
In Witness whereof I the said Lucien Gaulard have hereunto set my hand
and seal this twenty third day of August in the year of our Lord one thousand
eight hundred and eighty three
Witness:-
J. E. PICKERING.
18 Warwick Street
Regent Street
London W.
LUCIEN GAULARD (L.S.)