Improvements in and relating to Electric Arc Lamps.
Year: 1892

page_text: Date of Application, 16th Aug., 1892
Complete Specification Left, 15th May, 1893-Accepted, 1st July, 1893
PROVISIONAL SPECIFICATION.
Improvements in and relating to Electric Arc Lamps.
I, HUGH WATT of 107 St. George's Square in the City of Westminster S.W.,
Gentleman, do hereby declare the nature of this invention to be as follows:-
My invention relates to electric arc lamps and more especially to lamps of the
kind or class in which the upper carbon rod in descending actuates a wheel train
which finally gives motion to a brake-wheel to which a brake can be applied by
means of a regulating coil or solenoid. Such a lamp is described in the Specification
of Letters Patent No. 9642 dated 6th June 1891 granted to me.
An important feature of my invention consists in mounting the regulating coil or
Bolenoid and the wheel train on the same base or frame so that when the upper
carbon rod together with the wheel train is lifted for the purpose of striking the
arc or separating the carbons the said regulating coil or solenoid which controls the
brake is lifted at the same time. The position of the regulating coil relative to
the brake and brake-wheel is thereby not altered when the arc is struck.
In order to do this I sometimes attach the regulating coil or solenoid to a bracket
carried by the frame in which the wheel train is mounted and I arrange to connect
the said coil or solenoid to the circuit by flexible leads or wires so as to allow the
coil to be raised as hereinabove described. The coil or electro-magnet which is
used to raise the wheel train frame and upper carbon rod and thus strike the arc is
connected in series with the coil or solenoid which controls the brake, and both are
joined in series with the arc.
I make the brake wheel of a shape which is not truly circular so that if an even
pressure be maintained on the brake lever by means of the regulating coil the said
brake wheel will slip and escape the brake at certain periods during a revolution,
the mechanism is thus prevented from sticking and a more certain and accurate feed
of the carbon ensured.
My improved lamp is intended for use on a parallel or multiple system of
distribution and can be arranged to be worked by either an alternating or a direct
In both cases I may use
current without necessitating any mechanical alteration.
laminated cores for the striking and regulating coils or electromagnets and wind
the same with stranded wire.
Dated this 16th dar of August 1892
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Arc Lamps.
I, HUGH WATT, of 107 St. George's Square in the City of Westminster, S. W.
Gentleman, 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 relates to electric arc lamps and more especially to lamps of the
kind or class in which the upper carbon rod in descending actuates a wheel train
which finally gives motion to a brake-wheel to which a brake can be applied by
means of a regulating coil or solenoid. Such a lamp is described in the Specification
of Letters Patent No. 9642 dated 6th June 1891 granted to me.
An important feature of my present invention consists in mounting the regulating
coil or solenoid on the same base or frame as the wheel train or clockwork

page_text: mechanism of the lamp so that when the upper carbon rod together with the wheel
train or clockwork mechanism is lifted for the purpose of striking the arc or
separating the carbons, the said regulating coil which controls the brake is lifted at
the same time. The position of the regulating coil relative to the brake and brake
wheel is thereby not altered when the arc is struck.
Another feature of my invention relates to the shape of the brake wheel which
is not truly circular so that the feed of the lamp is lessened or intensified to suit
the requirements of various alternating systems. The said brake wheel will thus
slip and escape the brake at certain periods during a revolution, preventing the
mechanism from sticking and a variable feed of the carbons is ensured so as to
maintain a proper arc.
The accompanying drawing is a view of the mechanism of an arc lamp constructed
with improvements according to my present invention.
A is the lamp-frame, B is the rod which supports the upper carbon; C is a
frame-work which supports the wheel train or clock-work mechanism of the lamp.
The said frame-work C is adapted to be raised by the action of a solenoid D which
draws down the plunger D¹ and thereby operate the arm D¹ of rocking shaft D'
when the arc is to be struck. E is the solenoid which regulates the feeding of the
lamp. The said solenoid E is carried on a bracket C₁ which is secured to the
movable framework C. I prefer to arrange that the weight of the upper carbon,
carbon-holder and rod shall effect the downward movement and feeding of the said
carbon. I arrange that the said downward movement of the upper carbon shall
through the wheel train or clockwork mechanism operate a brake wheel C. The
feed is regulated by the solenoid E which cau act on a plunger E' and, through the
medium of a rocking lever E' pivotally secured to the frame C cause a brake shoe
or block E to press more or less heavily on the periphery of the brake wheel C
I find it advantageous to arrange two springs E E' in connection with the rocking
lever which are arranged to act differentially on the said lever and thus facilitate
the operation of the same, the said springs may be adjusted by means of the
screws E E'.
The periphery of the brake wheel C' is not truly circular but is made slightly
flat on one side by filing or otherwise. The wheel therefore will slip every time
the flattened part of its periphery comes opposite the brake hence the lamp will on
the whole feed more quickly, that is, the brake wheel will act as if it were smaller.
When the lamp is being regulated so as to maintain a proper length of arc with
carbons that are smaller than those which were used with the lamp before, the feed
will have to be quicker because the carbons burn away more quickly. Then instead
of putting in a new brake wheel of slightly smaller diameter than the old brake
wheel, the old wheel may be reduced a little at one part of its periphery which as
above stated makes the lamp feed more quickly. The lamp does not flicker owing
to the feed being more sudden at one time, once in every revolution of the brake
wheel, because the total amount of feeding of the carbons for one revolution of
said wheel is very small.
By my method of mounting the regulating coil E, I gain an important advantage,
inasmuch as the relative position of the said coil and its plunger which is connected
with the brake and the framework C is not altered when the arc is struck and the
said framework is lifted. I employ flexible leads F to connect the wire on the
solenoid E with the wire forming the remainder of the lamp circuit.
I can arrange my improved lamp for either series or parallel working and when
the plungers of the solenoids are laminated and the said solenoids wound with
stranded wire the lamp may be operated by either alternating or direct currents
without any mechanical alteration.
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 electric arc lamp of the kind described, mounting the regulating

page_text: solenoid on the framework of the wheel train, substantially as, and for the purpose,
specified.
2. In an arc lamp of the kind described, the provision of a brake wheel which is
not of circular form, as, and for the purpose, specified.
3. The improved arc lamp constructed substantially as described with reference
to the accompanying drawing, and operating as specified.
Dated this 15th day of May 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.