An Improved Electric Arc Lamp.
Year: 1897

page_text: An Improved Electric Arc Lamp.
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:-
This invention relates to a constant potential focussing arc lamp in which the
feed of the carbons is effected by the gravity of a weight attached to the upper or
positive carbon holder and guided in the tubular frame of the lamp. To the weight
is attached a cord passing over a pulley mounted at one end of an unequal armed
arc-striking lever pivoted to the head of the lamp frame the cord then passing
under a sheave whose rotation is controlled by a train of wheels and an escapement,
thence over a pulley mounted on the other arm of the arc-striking lever and down
to the lower carbon holder. The weight of the upper carbon holder preponderates
over that of the lower carbon holder so that the latter is raised by the descent
of the former, when the cord is free to run, but when the running of the cord is.
prevented the preponderant weight of the upper carbon holder is resisted by a
spring connected to the long arm of the arc-striking lever to the short arm of
which is connected a stop finger which is brought by the oscillation of the arc-
striking lever in one direction into the path of the escapement. The amplitude
of motion of the arc-striking lever is limited by adjusting screws and to the short
arm are connected the core armatures of two electro-magnets which act in opposi-
tion to the spring, the magnets being in series to one another and in- a shunt to
the arc.
Carbons having been inserted, after the lower carbon holder has been drawn
down and the upper one raised the spring is forcibly overcome and the arc-striking
lever is oscillated sufficiently to move the stop finger out of the path of the escape-
ment whereupon the cord is free to run until the carbons come in contact
whereupon the spring being allowed to act the arc-striking lever resumes its
normal position thereby separating the carbons the distance required for striking
the arc.
When the circuit is closed through the lamp the current energizes the magnet
coils, the core armatures are strongly attracted, the spring is overcome, and the
arc striking lever oscillated in the opposite direction so as to thereby lower tho
upper and raise the lower carbon holder thus bringing the carbons in contact.
The current then passing through the carbons ceases to energize the magnets and
the spring oscillates the lever back again thus striking the arc.
When by the consumption of the carbons the length of the arc becomes excessive,
a greater proportion of the current passes through the magnets which are gradually
energized until the arc-striking lever is oscillated to a sufficient extent to release

page_text: the escapement whereupon the cord is free to run and allow the carbons to be fed
up by gravity so as to maintain the arc constant.
Dated this 21st day of May 1897
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
An improved Electric Arc Lamp.
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 160/2, Lambeth
Road, London, S.E., 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:-
-
This invention relates to a constant potential focussing arc lamp, in which the
feed of the carbon is effected by the gravity of a weight attached to the upper or
positive carbon-holder M, and guided in the tubular frame of the lamp O. To the
weight is attached a cord passing over a pulley K, mounted at one end of an unequal
armed arc striking lever D, pivotted to the head of the lamp frame, the cord Ühen
passing under a sheave P, whose rotation is controlled by a train of wheels T T¹ and
an escapement R, thence over a pulley K¹ mounted on the other arm of the arc
striking lever D, and down to the lower carbon-holder N. The weight of the
upper carbon-holder M preponderates over that of the lower carbon-holder N so
that the latter is raised by the descent of the former, when the cord is free to run,
but when the running of the cord is prevented the preponderant weight of the
upper carbon-holder M is resisted by a spring J connected to the long arm of the
striking-lever D, to the short arm of which is connected a stop-finger S carrying
a plate S with a notch in it. This is brought by the oscillation of the arc-striking
lever on its axis I in one direction into the path of a pin on the escapement R.
The amplitude of motion of the arc-striking lever is limited by adjusting
screws L & L and to the short arni are connected the core armatures of two
electro magnets F & F¹, which act in opposition to the spring, the magnet-coils
being in series to one another and in a shunt to the arc.
Carbons having been inserted, after the lower carbon holder has been drawn
down and the upper one raised the spring is forcibly overcome and the arc-striking
lever is oscillated sufficiently to move the stop finger S so that the notch in the
plate S¹ frees the pin on the escapement R, this is then free to be oscillated by
a pin on the wheel T¹ whereupon the cord is free to run until the carbons come in
contact, whereupon the spring being allowed to act, the arc-striking lever resumes
its normal position thereby separating the carbons the distance required for
striking the arc.
When the circuit is closed through the lamp the current energizes the magnet-
coils E & E¹, the core armatures are strongly attracted by the fixed cores G & G¹,
the spring is overcome, and the arc-striking lever oscillated in the opposite
direction, so as to thereby lower the upper and raise the lower carbon holder, thus
bringing the carbons in contact. The current then passing through the carbons
ceases to energize the magnets and the spring oscillates the lever back again thus
striking the arc.
When by the consumption of the carbons the length of the arc becomes
excessive, a greater proportion of the current passes through the magnet-coils,
which are gradually energized until the arc-striking lever is oscillated to a sufficient

page_text: extent to release the escapement, whereupon the cord is free to run and allow
the carbons to be fed up by gravity so as to maintain the arc constant.
This are lamp can be used on continuous or alternating currents.
Having now particularly described and ascertained the nature of our said inven-
tion, 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 above described, and particularly