IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1884

page_text: I CHARLES LEVER of Bowdon in the County of Chester, Electrical Engineer
do hereby declare the nature of said Invention for "IMPROVEMENTS IN ELECTRIC
ARC LAMPS" 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 improvements in the electric arc light apparatus
described in the Specification of a formor Patent granted to me on the 3rd May
1882 N° 2092 and is intended to accomplish the following object viz. to enable
the electric arc lamps constructed according to my said previous Invention, to
be more effectively worked in series from a shunt or compound wound dynamo
machine or from a separately excited dynamo machine.
The accompanying Drawing is a vertical section diagram of so much of my
lamp and the parts connected therewith as will render my Invention understood.
R is a resistance arranged in or connected with the lamp and by preferenco
made equal to the normal arc; M M is an electro-magnet (or it might be a
solenoid) which is secured to the top part of the frame of the lamp. One limb L
of this magnet is wound with coarse wire and the other limb L is wound with
fine wire. The thick wire W represents the connection from the positive terminal
in the lamp to the top of the lamp frame. The broad headed iron screws J J¹ are
so adjusted and secured by their lock nuts as to enable the clutch to release the
upper carbon before they touch the poles of the electro-magnet M M. The screw S
is also adjusted and fixed by its lock nuts n, n so that it will not make contact
with the end G of the coarse wire on the limb L of the electro-magnet M M until
the screws J, J, touch the poles of the said electro-magnet. The other end of tho
thick insulated wire of limb L is connected to a resistance R, in this case about
equal to the normal arc, the said resistance being connected to the negative
terminal of the lamp. The fine wire on limb L of the electro-magnet M M is
connected one end to the positive and the other end to the negative terminal on
the lamp thus placing it in a shunt or derived circuit as is fully described in my
aforesaid Specification of Patent dated 3rd May 1882 N° 2092 and as represented
by wires w, w¹.
The action of this arrangement is as follows: The current from the shunt or
compound wound or separately excited or alternating curront dynamo having
magnetized the electro-magnet M M by flowing through the fine wire or shunt
coil on limb L' causes the said electro-magnet to attract its armature A and to

page_text: bring the carbons into contact with each other in the manner set forth in my
former Patent Specification. The main circuit is thus completed before the
screws J J touch the poles of the electro-magnet M M as already described and
the arc is formed in the lamp. Should however from any cause, the arc become
unduly lengthened the electro-magnet M M will attract armature A until the
screws J J¹ do touch the poles of the said electro-magnet or in other words until
screw S comes into contact with the end of the coarse wire G. The whole of the
current will then flow through the limb L of the electro-magnet M M and the
resistance R and armature A will be kept down and the lamp will be cut out. If
however the carbons should come into contact again the path of the current will
be practically short circuited the moment the carbons make contact, and the spring
which forms the arc will again draw up armature A and the lamp will be re-
lighted. In case a solenoid or bar magnet be used in the lamp the thick and thin
wire may be wound upon same and in a similar direction.
Care must be taken that the end G of the coarse wire on limb L of the electro-
magnet M M does not make contact with any part of the frame of the lamp. The
only electrical connection must be that through screw S and coarse wire G. The
contacts may be made of platinum to establish good electrical connection but they
must be substantial on the ground of durability.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the saine is to be performed I declare that what
I claim is
In electric arc lamps regulated on the shunt circuit principle the employment of
the adjustable regulating screw S passing through the armature A and serving to
cut out the lamp in case the circuit through the carbons be defective and which
completes a circuit through the coils of thick wire G on the regulating electro-
magnet or solenoid M and through the resistance R substantially as described and
shown.
Dated this Twenty first day of August 1881