Improvements in Electric Arc Lamps.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Electric Arc Lamps.
We, FRANÇOIS FESQUET, of 4, Quai de Seine, St. Ouen les Docks, in the Depart-
ment of Seine, France, Electrician, and JOHN WILLIAM KEYS, of 160, Lambeth
Road, London, S.E., Electrical Engineer, do hereby declare the nature of this
Invention to be as follows:-
Our Invention relates to means of automatically regulating the length of the
electric arc, the lamp being a shunt lamp and focussing and adapted to work
either with continuous or alternating currents. The carbon holders are connected by
being hung by sheaves in the bights of a cord whose ends are made fast to the
ends of an unequal armed rocking lever termed the arc striking lever having a
limited range of motion, the cord also passing over sheaves on said arms and under
a sheave intermediate of the other two fast with a brake wheel journalled on a lever
so pivoted that when raised by the pull of the cord passing under the brake wheel
sheave the rim of the wheel abuts against a fixed point acting as a brake to prevent
The free end
the rotation of the wheel and consequently the running of the cord.
of the brake wheel lever is presented in the path of the striking lever so that when
the latter is oscillated in one direction by the action of a solenoid it draws down
the brake wheel so as to permit the cord to run freely. The arc striking lever is
connected through a link and lever or otherwise with the core of a solenoid coil
in shunt to the arc and acting in opposition to a spring and to the weight of the
lower carbon holder. The upper carbon holder is weighted so that it preponderates
over that of the lower carbon holder when the cord free to run, but except when
the brake wheel lever is forcibly lowered so that the wheel is released, the lower
carbon holder being suspended from the longer arm of the striking lever over-
balances the upper carbon holder and so allows the brake wheel to be raised until
it is braked, thus keeping the carbon holders apart. When the carbons are
inserted the upper carbon holder is drawn slightly downwards so as to oscillate
the arc striking lever and cause it to release the brake wheel and allow the cord
to run freely until the carbons come in contact. The negative carbon holder will
then preponderate and oscillate the arc striking lever in the opposite direction
to the proper extent for striking the arc thus braking the cord.
When the lamp circuit is closed the solenoid core is attracted by the current
passing through the coil, the spring is put in tension, and the arc striking lever
The current now goes through
oscillated so as to bring the carbons in contact.
the carbons and the difference of potential at the terminals of the coil decreasing,
the spring retracts the core and oscillates the arc striking lever in the opposite
direction, thus separating the carbons to the proper extent and striking the arc.
As the length of the arc increases, the difference of potential increases at the
terminals of the lamp and consequently a larger current goes through the coil the
core of which is attracted, until the arc striking lever causes the release of the brake
wheel thereby permitting the cord to run freely and consequently allowing the
positive carbon holder to descend by its own weight and to raise the negative

page_text: carbon holder to the extent necessary to maintain constant the length of the arc
whereupon the brake wheel is again braked as before.
For an alternating current lamp the solenoid core would be a split tube and
the frame of the coil would also be split to prevent excessive heating by Foucault
currents.
Data hi
1
1007
Improvements in Electric Arc Lamps.
We, FRANÇOIS FESQUET, Electrician, 4, Quai de Seine, St. Ouen les Docks,
Paris, and JOHN WILLIAM KEYS, Electrical Engineer, 160 and 162, Lambeth Road,
London, S.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 object of our invention is to secure a simple, economical and reliable means
of automatically regulating the length of the voltaic arc in an electric lamp. This
lamp is a shunt lamp & focussing, and can work with. either continuous or alter-
nating current.
DESCRIPTION.
The principle of our lamp is based on the action of a motor with a counterweight.
The counterweight which works it has two duties to perform (a) blocking the lamp
when at rest (b) regulating the feed of the arc when working.
This lamp shewn in the enclosed drawing, has two Carbon holders 1 & 2
attached respectively to the rods 8 & 9, which are suitably guided by means of the
cross-bars 4 & 6, along the props D which connect the top frame C and the bottom
frame E. The rod 8 of the Positive Carbon holder 1 carries a counterweight 10,
guided by the props 11.
On the cross-bars 4 and 6 there are small wheels 5 round which is wound a
suspension cord, the ends of which are suitably fixed to the ends of a lever J,
called the striking lever. This cord is wound also round the wheels L and M,
mounted on the striking lever J and also round a pulley F, screwed to a brake-
fly wheel S both being supported to turn on a stud or spindle G fixed on the
lever H.
The lever J oscillates round the centre-pin of a bracket K mounted underneath
the top-frame C, and its range is adjusted by regulating screws on the lever J.
This lever is connected, through the connecting-rod O, to the lever P of the coil N.
The lever H oscillates also round the centre-pin of a bracket I mounted on the
top-frame C, near the wheel M.
T
From the above description it will be seen that the weight of the counter-
weight 10 reacts on the fly wheel S, which, when the lamp is at rest, is blocked
against the top-frame C and consequently prevents all movements of the carbon-.
holders. -
At one end of the lever J there is a regulating screw 15, the tip of which rests
on the lever H carrying the flywheel S.
By the position of the centre of oscillation of the lever J, at a third of its length,
this lever, under the pull of the rod 9 which overbalances the rod 8 and the counter-
weight 10, turn's round and comes to its resting place.
Such is the position of the various pieces when the lamp carries no carbons.

page_text: To put the carbons on it is only necessary to raise the counterweight 10 until
it reaches the bottom frame E, this raises the carbon holder 1, and at the same
time lowers the carbon holder 2 to the same distance, as these two carbon-holders,
as explained above, are connected together by a cord. The carbons are now put
in. Then you draw the counterweight slightly downwards to overcome the pull of
the rod 9. The striking lever J will now oscillate round its centre until the
regulating screw 15 rests on the lever H and lowers this latter, which makes the
flywheel turn freely again and allows the cord to slide along. The counterweight
must be pressed down until the carbons come in contact.
Then the rod 9 will again overbalance the rod 8 and the striking lever J will
be driven round up to its resting place. This slight backward motion which is
produced automatically brings the carbons to the proper distance apart for the
striking of the arc.
The Coil N is in shunt on the arc circuit, and its lever P carries on one end a move-
able core V, and at the other end a mortice allowing a certain amount of play to the
connecting rod O and the striking lever. The lever P also carries a spiral spring X,
the end of which Y is connected to the hanger 3 through a rod and regulating
nut Z.
When the lamp circuit is closed, the current goes through the coil N, the move-
able core is abruptly attracted against the fixed core W of the coil N, and drags
with it the lever P which oscillates round Q. This dragging of the lever P pulls up
the spring X, and through the rod O lifts up the lever J. This oscillation of the
lever J lifts up the rod 9 and at the same time lowers down the rod 8, and the
carbons come in contact.
The current now goes through the two carbons and the difference of potential
at the terminals of the coil decreases, consequently the moveable core V ceases to
be attracted, the spring X pulls back the lever P. The striking lever follows suit,
the carbons are separated and the arc is struck.
The length of the arc increases as the carbons burn away, and as the resistance
increases, the difference of potential increases at the terminals of the lamp, and
consequently a larger current goes through the coil N.
The moveable core V is gradually attracted by the fixed core W until the
screw 15 rests on the lever H. The fly-wheel S is now free and can turn round,
a small quantity, so as to always keep the same length of arc.
The spring X and the moveable core V will thus act until the carbons are burnt
out.
ALTERNATING CURRENT LAMP.
This lamp has the same organs and works in the same way as the one above
described. The coil N and the moveable core V only are replaced by another coil
with the bobbin slit longitudinally, and the core is replaced by an iron tube slit
in the same way, to prevent undue heating by Foucault currents.
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;-
-
The general arrangement of the Arc-lamp, as described, and more specially in
arc lamps: (1) the combination of the striking lever J, (2) the lever Ĥ carrying
the flywheel S, (3) the coil N, (4) the lever P, (5) the rod connecting the
levers P&J, substantially as described and illustrated by the enclosed drawing.
F. FESQUET.