Improvements in or relating to Electric Lighting.
Year: 1889

page_text: Date of Application, 26th Jan., 1889
Complete Specification Left, 4th Sept., 1889-Accepted, 16th Nov., 1889
Improvements in or relating to Electric Lighting.
A communication from Dr. STEFAN DOUBRAVA, of Neugasse, Brünn, in the Empire of
Austria, Electrician.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E. do hereby declare the nature of this invention to be as follows:-
The improvements in electric incandescent lighting which form the subject of the
present application relate to
1st. A now distribution of the electric current.
2nd. The application of this distribution to electric incandescent lighting.
This new distribution of the current consists in employing an alternating current
produced by charging and discharging condensers while dynamos for continuous
currents are employed. The continuous current produced by the dynamo is changed
into alternating currents in quick-succession by a special apparatus and this consists
of a series of insulated metal segments which are arranged in an iron box similar to
the commutators of dynamo machines. One third of these blades is connected with a
metal disc on one side of the apparatus the second third with a similar metal disc on
the other side and the other third is entirely insulated so that each of the segments
which is in contact with one of the sides is perfectly insulated from the next segments
which are connected to the other side. Two sliding contacts bear one against each of
the metal discs at the sides of the apparatus and by means of this apparatus it is
possible to interrupt the current several thousand times per second. Alternating
currents of opposite direction can be produced by this apparatus which I call the
GE disjunctor "and the condensers in two ways viz. (a) by charging and discharging
the condenser or (b) by charging the condenser successively in opposite directions.
In the first of these methods the poles of a generator of continuous currents are
connected with the sliding contacts of the disjunctor and one of the coatings of a con-
denser is connected with a brush bearing upon the periphery of the disjunctor whilo
the other is connected with one of the sliding contacts. When the brush bears against
one of the segments connected with the other sliding contact the condenser will be
charged and as soon as the brush bears against one of the segments connected with
the sliding contact which is connected with one of the coatings of the condenser this
latter will be discharged.
It will be seen from this that the charging and discharging current-waves in the
circuit between the disjunctor and the condenser are of opposite directions. In this
arrangement the charging current is quicker than the discharging current; the two
current-waves are therefore not equal. As however a perfect equality of the current
waves is essential for lighting purposes the following arrangement is made:
The generator for continuous currents is connected with the sliding contacts of the
disjunctor and the coatings of the condenser are connected each one with one of two
brushes bearing against the periphery of the disjunctor. These brushes are arranged
and placed in such a manner that they always touch segments of opposite polarity so
that in one position the condenser is charged in one direction and in the next position
in the other direction and in this manner the current waves of opposite directions in
the circuit are of perfect equality.
Those current-waves are employed in the following peculiar manner for the produc
tion of incandescent light; the current waves are by means of inductors changed into
currents of such high tension that they can produce sparks. These inductors are
simple cylindrical bobbins with an iron core consisting of an insulated bundle of soft
iron wire, with ticker coils for the principal current and thinner coils for the branch
current, any suitable kind of inductor may however be used.

page_text: By means of the current waves changing several thousand times per second small
inductors of say a few centimetres in length can produce sparks which follow each
other in such quick succession that the eye only seems to seo a continuous arc of light.
These currents of high tension are conducted into lamps filled with rarefied gas for the
purpose of rendering incandescent plates or other conductors which are not connected
together. These plates or conductors are of a material difficult to fuse such as platinum,
irridium, carbon or the like and are fastened to platinum wires and have a space of
about 1 millimetre between them. The gas in the incandescent lamp must be rarefied
to such an extent that the cracking noise audible during the passage of the sparks
in gases of ordinary atmospheric pressure disappears. When the plates or conductors
are connected with the poles of one of the above-mentioned inductors they will be
rendered incandescent and emit light. These plates or conductors may be circular or
square or of any desired shape, they may be cylinders or prisms one arranged inside
the other or they may be corrugated if it is desired to increase the surface.
Each lamp has its own inductor to which the wires of the lamp are attached in any
suitable manner and the lamps are arranged in multiple arc in the circuit of the con-
denser, each lamp may however be provided with its own condenser.
Improvements in or relating to Electric Lighting.
A communication from Dr. STEFAN DOUBRAVA, of Neugasse, Brünn, in the Empire
of Austria, Electrician.
I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
M.I.M.E., 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 :-
The improvements in electric incandescent lighting which form the subject of the
present application relate to –
1st. A new distribution of the electric current.
2nd. The application of this distribution to electric incandescent lighting.
This new distribution of the current consists in employing an alternating current
produced by charging and discharging condensers while dynamos for continuous
currents are employed.
The continuous current produced by the dynamo is changed into alternating currents
in quick succossion by a special apparatus represented in Fig. 1 and this consists of a
serios of insulated metal segments which are arranged in an iron box (Fig. 1) similar
to the commutators of dynamo machines. One third of these blades is connected with
a motal disc a on one side of the apparatus, the second third with a similar metal disc b
son the other side and the other third is entirely insulated so that each of the segments
which is in contact with one of the sides is perfectly insulated from the next segments
which are connected to the other side. Two sliding contacts c d bear one against each
of the metal discs ab at the sides of the apparatus and by means of this apparatus it
is possible to interrupt the current several thousand times per second. Alternating
currents of opposite direction can be produced by this apparatus (which is called the
disjunctor ") and the condensers in two ways viz. (a) by charging and discharging
the condenser or (b) by charging the condenser successively in opposite directions.
In the first of these methods (diagram Fig. 2) the poles of a continuous current
generator G are connected with the sliding contacts of the disjunctor D and one of the
coatings of the condenser C is connected with a brush a bearing upon the periphery
of the disjunctor while the other is connected with one of the sliding contacts. When
the brush bears against one of the segments connected with the other sliding contact
£6

page_text: the condenser C will be charged and as soon as the brush bears against one of the
segments connected with the sliding contact d which is connected with one of the
coatings of the condenser this latter will be discharged.
It will be seen from this that the charging and discharging current-waves in the
circuit m n o p between the disjunctor and the condenser aro of opposite directions.
In this arrangement the charging current is quicker than the discharging current ;
the two current waves are therefore not equal. As however a perfect equality of the
current waves is essential for lighting purposes the following arrangement represented
in diagram Fig. 3 is made.
The generator G for continuous currents is connected with the sliding contacts c d of
the disjunctor and the coatings of the condenser C are connected each with one of two
brushes ab bearing against the periphery of the disjunctor. These brushes aro
arranged and placed in such a manner that they always touch segments of opposite
polarity so that in one position the condenser is charged in one direction and in the
next position in the other direction and in this manner the current waves of opposite
directions in the circuit m n o p are of perfect equality.
These current waves are employed in the following peculiar manner for the produc-
tion of incandescent light the current waves are by means of inductors changed into
currents of such high tension that they can produce sparks. These inductors are
simple cylindrical bobbins with an iron core consisting of an insulated bundle of
soft iron wire, with thicker coils for the principal current and thinner coils for the
branch current similar to Rumkorff inductor but any other suitable kind of inductor
may be used.
By means of the current waves changing several thousand times per second,
small inductors of say a few centimetres in length can produce sparks which follow
each other in such quick succession that the eye only seems to see a continuous
arc of light. These currents of high tension are conducted into lamps filled with
rarefied gas for the purpose of rendering incandescent plates or other conductors
which are not connected together. These plates or conductors ab Fig. 4 are of a
material difficult to fuse such as platinum, irridium, carbon or the like and are
fastened to platinum wires and have a spaco of about 1 millimetre between them.
The gas in the incandescent lamp must be rarefied to such an extent, that the
crackling noise audible during the passage of the sparks in gasos of ordinary
atmospheric pressure disappears. When the plates or conductors are connected
with the poles of one of the above mentioned inductors they will be rendered
incandescent by the sparks passing between them and emit light. These plates or
conductors may be circular or square or of any desired shape they may be cylinders or
prisms one arranged inside the other as represented in Fig. 5 or they may be
corrugated as represented in Fig. 6 if it is desired to increase the surface.
Each lamp has its own inductor and is attached to it as represented in Fig. 7.
The inductor A is provided at its bottom with an insulated plate P on which are
fixed two metal springs a b which are electrically connected with the poles of the
coil of the inductor. The hooks or strips cd which are electrically connected
with the platos ef of the lamp are introduced or passed under the springs a b for
the purpose of fastening the lamp to the inductor. The ends of the primary
wiro m m' are situated at the top of the inductor.
The lamps are arranged in multiple arc in the circuit of the condenser as
represented in the diagram Fig. 8 in which a a¹ a² a³ are the lamps, each lamp
may however be provided with its own condenser.
Having now particularly described and ascertained the naturo of this inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. The method of changing a continuous current into a rapidly alternating
current consisting in charging and discharging a condenser or charging it alter-
nately in opposite directions by means of a disjunctor substantially as herein
described.

page_text: 2. The method of changing the alternating current produced. as described in
claim into a current of high tension by letting the alternating current act on
an inductor wound similarly to a Rumkorff apparatus substantially as herein
described.
3. The employment of the high tension current produced as described in claim 2
for incandescent lighting by rendoring plates or other bodies of material difficult
to fuse incandescent in rarefied gas by the passage of sparks substantially as herein
described.
4. An electric incandescent lamp which has no continuous filament but in which
two electrodes in the form of plates and situated very near each other are rendered
incandescent by a rapid succession of sparks passing between them and produced
by inductors excited by an alternating current substantially as herein described.
Dated this 4th day of September 1889.