Improvements in Electric Arc Lamps.
Year: 1890

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COMPLETE
SPECIFICATION.
Improvements in Electric Arc Lamps.
I, FREDERIK VILHELM ANDERSEN of 14 Westdown Road, Catford in the County of
Kent Electrical Engineer, 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:-
My invention for improvements in electric arc lamps relates to that class of arc
lamp in which the two carbon holders are suspended by means of cords wound in
opposite directions round a pulley and in which each carbon holder is connected to a
soft iron core working in a solenoid, one solenoid being arranged in the main circuit
and tending when excited to draw the carbons apart, and the other being arranged
as a shunt to the arc and tending when excited to draw the carbons together.
My invention has for its objects to provide improved means for conducting the
electric current to the carbons of the lamp, to provide an improved construction of
core for the solenoids of the lamp suitable more especially for lamps used with alter-
nating currents, to provide an improved arrangement for preventing "pumping," and
to more efficiently guide the lower carbon holder; and consists in conveying the
current to the carbons through the bearings of the pulley and through the supporting
cords, in constructing laminated cores for the solenoids so that their magnitism is
readily reversed when alternating currents are employed, to substitute for the ordinary
dash pot an electro magnetic arrangement comprising a copper disc geared to the
supporting drum and rotating between the poles of an electro magnet, and in guiding
the lower carbon holder by means of a wheel attached to its upper extremity and
sliding loosely within the lining tube of the shunt solenoid and of a wheel attached to
an extension of the lamp and bearing on the outside of the said carbon holder.
An arc lamp constructed according to my invention is more especially designed
for working in parallel with incandescent lamps in a constant potential circuit in which
the difference of potential between the mains is from 100 to 110 volts., two of the arc
lamps being arranged in series between the mains.
The laminated construction of core for the solenoids is more especially suitable for
use in an alternating current circuit.
When the lamps are employed in a constant current circuit the electro magnetic
damper may be dispensed with.
In the accompanying sheet of illustrative drawings
Fig. 1 is a vertical section of an arc lamp constructed according to my invention.
Fig. 2 is an elevation with the casing in section.
Figs. 3, 4, 5, are horizontal sections of the same.
The positive or upper carbon holder 1, which also serves as the core of the main
solenoid 2, consists of an iron tube packed with iron wires and carrying at its lower
extremity a clamp 4 for holding the positive carbon and at its upper extremity a screw
plug 5. One end of an insulated copper wire cable 6 passing over a vulcanite or
suitable insulating pulley 7 is secured to the plug 5 and the other end to the
pulley 7.
The lower or negative carbon holder 8 consists of a light square bent rod carrying
the clamp 9 for holding the negative carbon and having secured round it where it
passes through the shunt solenoid 10 a series of iron wires held together by means of
the end caps 11 and intermediate binding wires. One end of an insulated copper wire
cable 12 passing over the pulley 7 is secured to the upper end of the carbon holder 8
and the other end to the pulley 7.
The pulley 7 has secured centrally to one face the toothed wheel 13 and a metal.
disc carrying the pin 14 while a brass disc carrying a pin 15 is secured centrally to
the other side. The pins 14 and 15 are supported respectively in the insulated

page_text: bearings 16 and 17 their ends projecting through the said bearings. Springs 18 and 19
secured to the bearings 16 and 17 respectively bear on the projecting ends of the
pins 14 and 15 the points of contact being made of platinum. The ends of the cable 6
are connected to the pin. 14 and to the positive carbon holder 1 and the ends of the
cable 12 to the pin '15 and negative carbon holder 8, the two cables lying in separate
grooves in the circumference of the pulley 7 and being wound in opposite directions.
The springs 18 and 19 serve to secure a more perfect electrical connection between!
the bearings 16 and 17 and the pins 14 and 15 which is not likely to be impared
by dirt or other causes.
The wheel 13 gears with a pinion 18 connected to a copper disc 19 which on the
motion of the pulley 7. is rotated at a high velocity between the poles 20 and 21 of
an electro magnet 22, the core of the magnet being formed of a flat bar bent to the,
required shape or preferably made in two or more pieces. The core after passing
centrally through the coils is brought back again externally to the said coils so that
the two poles 20, 21 are adjacent to one another; it is secured by the external: part.
of the core to the top cover 23 of the lamp.
The lower carbon holder 8 is guided by means of a wheel 24 sliding loosely within,
the lining tube of the solenoid 10 and of a wheel. 25 mounted on an extension of the.
said tube and bearing on the outside of the carbon holder.
The globe 25 is supported between the rings 26 and 31 by means of wiring and
the ring 26 is secured to rods 27 capable of sliding vertically and of being secured
in their uppermost position by the chain 30. When required to renew the carbons
the globe is simply lowered and the carbons replaced. The opening in the ring 31 is
closed by a cover 32 held in position by three springs 33.
The circuit of the lamp is from the positive terminal 28 through the electro-
magnet 22 to the bearing 16, pin 14, cable 6, positive carbon holder 1, carbons, negative
carbon holder 8, cable 12, pin 15, bearing 17, main solenoid 2, to the negative
terminal: 29: The terminals of the shunt or fine wire solenoid 10 are connected
to the bearings: 16 and 17, the solenoid 10 being thus arranged as a shunt to
the aro.
Normally the weight of the positive carbon and holder is sufficient to bring the
carbons in contact and on the passage of the current the solenoid 2.draws the carbon
holder 1 upwards separating the carbons and forming the arc. A portion of the
current dependant on the resistance of the arc then passes through the shunt
solenoid: 10 which tends to draw. its core upwards and decrease the length of the
arc, the two acting together on the well known differential principle to keep a
practically constant length of are notwithstanding the consumption of the carbons.
The copper disc 19 rotating between the poles 20, 21 of the electro-magnet 22 offers
resistance to sudden motion of the disc 7 and so serves to prevent what is commonly
known as "pumping" in an arc lamp.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
-
1: In an arc lamp leading the current to the carbon holders by means of insulated
conducting cables passing in opposite directions over a pulley from which the said
-holders are supported and through which they are mechanically connected substantially
as described.
2. In an arc lamp constructing the cores of the solenoids of iron wires supported
around or within the rod or tube carrying the carbon holders substantially as described.
and for the purpose specified.
3. In an arc lamp the substitution for the ordinary dash pot arrangements of a
copper disc geared to the feed mechanism of the lamp and rotating between the poles
of an electro-magnet having a core constructed. of, one or more pieces of flat bar
bent to the required shape so that the two poles are adjacent to one another, substantially
as described and for the purpose specified.

page_text: 4. In an arc lamp guiding the lower or bent carbon holder substantially as described
with reference to the drawings.
5. The construction of arc lamp substantially as described with reference to the
drawings.
Dated this 2nd dose of Anvil 1800
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents..