Improvements in Electric Arc Lamps.
Year: 1897

page_text: Date of Application, 24th Apr., 1897-Accepted, 29th May, 1897
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
A communication by FRITS HANSEN, of Rendnitz, near Leipzig, in the Empire of
Germany, Electrician.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E. of The Agency for Foreign
Patent Solicitors 6, Lord Street, Liverpool and 6, Bank Street, Manchester, both in
the County of Lancaster, 118, New Street, Birmingham in the County of Warwick,
and 322 High Holborn in the County of Middlesex, Civil 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 :-
In electric arc lamps in which the regulation of the movement of the carbons
depends on the action on a movable iron core of a solenoid lying in a main or shunt
circuit, the extra or counter currents induced in the solenoid offer a considerable
resistance to the primary current flowing through the solenoid. This resistance
increases with the depth to which the iron core penetrates into the solenoid so that
the strength of the primary current traversing the coil depends not only on the
transfer resistance between the carbons but also on the constantly altering resistance
produced in the solenoid itself. It is evident that this alteration of resistance of the
solenoid deleteriously influences the regulating device.
In order to maintain at a constant strength the counter currents induced in the
solenoid and to thus keep the resistance of the same constant, a cone-shaped iron
body is arranged inside the solenoid, which iron body allows the induced counter
current to appear from the first at a certain strength so that the iron cylinder which
is drawn into the solenoid with the increasing strength of current, no longer exerts
any essential influence on the production of counter currents. The strength of the
primary current flowing through the solenoid consequently then undergoes only so
small an alteration on the insertion of the iron core that certainty in the working of
the regulating device can no longer be thereby affected.
The working of the regulating mechanism is here a more exact one as the regulating
mechanism is provided with a peculiar, particularly susceptible and instantaneously
acting stop device, and the regulating chamber is insulated from the burner chamber
in such a way that no warmth can be communicated from the latter to the regulating
chamber, and thus the formation of deposits in this regulating chamber is avoided
which otherwise would very deleteriously affect the regulating mechanism of the
lamp.
In the accompanying drawings
Figure 1 is a side elevation of this improved arc lamp;
Figure 2 a view, from the opposite side, of the regulating mechanism of the lamp ;
Figure 3 a plan view of same;
Figure 4 a partial elevation showing the automatic action;
Figure 5 is a vertical section of the regulating solenoid; and
Figure 6 a cross section of same.
On a disc a, two supports 6 6' are mounted opposite one another to receive the
bearing knife edges c c¹ of a gearing frame d which can make a short oscillation on
the said knife edges. A chain wheel is mounted in the frame d with a chain i
unning over it and connecting the carbon-holding cross-bars g h. The knife edges c c¹
are so arranged on the framed that the upper periphery point at which the chain

page_text: connected with the upper carbon leaves the chain wheel, falls in the axis of oscillation
of the frame. Consequently on the frame d swinging out, the chain end for the upper
carbon undergoes no movement, whilst the chain end connected with the lower carbon
crossbar is raised or lowered with the chain wheel which oscillates as a one-armed
lever. By this arrangement the point of combustion remains constant and the arc is
struck by lowering the lower carbon.
The electric regulating device consists of a solenoid k (Figures 5 and 6) lying in
shunt circuit, which solenoid differs from the forms of construction hitherto known
by its obtaining its support, not by means of an inner metal holder, but by means of a
metal casing which encloses it from the outside. The inner holder or spool forms
merely a thin partition between the wire coil and the iron core and is a non-metallic
body.
In order to afford a better equalisation of temperature the outer sheet metal
casing is perforated.
In the hollow inner chamber of the solenoid, a hollow iron cone m is fixed. This
cone projects from below into the coil, while an iron cylinder n is co-axially arranged
over the same and may be lowered from above into the coil and over the iron cone.
The iron cylinder n is guided in a tube o first placed co-axially upon the solenoid,
Figure 5, and is so suspended on the long arm of a lever p that when the coil is free
from current it penetrates from above into the same to about one third of the height
of the coil. The suspension lever is revoluble or pivoted on a support 7,
Figures 1 and 2, and its shorter arm is attached by means of a link to the frame d.
The latter in an inoperative condition rests in consequence of its own weight with
its foot d' on the disc a and holds the iron cylinder in its highest position. A current
passing through the solenoid effects a downward movement of the iron cylinder
which in turn causes a swinging upwards of the frame d with the chain wheel and
thereby a lifting of the outer end of the chain and the approaching of the lower carbon
to the upper one.
By means of the iron cone m and the part of the iron cylinder constantly
playing in the coil, a large part of the magnetic lines of force arising in the coil are
combined or closed so that the counter current induced in the solenoid emerges from
the first at a certain strength. On the inward movement of the iron cylinder into
the coil the strength of the original counter current is only quite immaterially
increased, in consequence of the arrangement of the iron cone which absorbs to a
large extent the lines of force arising in the lower part of the coil so that the iron
cylinder in a deeper position really alters the course of the lines of force but exercises
no essential influence on the production of the counter current. As the strength of
the primary current flowing through the solenoid depends on the strength of the
counter current, the primary experiences only a very minimum diminution on a
deeper insertion of the core, which diminution does not affect the good working of
the lamp because the counter current in the above described arrangement remains
almost constant.
The adjustment of the carbons corresponding to the consumption or burning away
takes place by the action of the weight of the upper carbon crossbar by means of the
regulating mechanism arranged in the oscillating framed. The regulating mechanism
consists of a pendulum dis: S with pallets S' which engage in a scape wheel t.driven
by the chain wheel and regulate the movement of the said scape wheel. The stopping
of the regulating mechanism takes place by means of a flyer S2, Figures 2, 3 & 4,
radially arranged on the pendulum disc and simultaneously serving as a wind brake,
which flyer may come into engagement with a tongue u of a lever u revolubly
mounted at u², said lever resting on a roller de mounted on the movable frame d and
thus being raised and lowered by the oscillations of the frame d.
The action of this checking or stopping device is thoroughly certain and
instantaneous because the stopping lever u shares in the up and down oscillating
movement of the frame and the pendulum dise, and thus the tongue a¹ of the same
assumes a position each time opposite the axis of the pendulum disc. The releasing
and arresting of the flyer S2 mounted on the pendulum disc takes place thus always

page_text: in the centre of its course of oscillation and by means of the oscillation of the lever
tongue u' which radially retires from or approaches to the pendulum disc.
If the lamp by means of the pole clamps or terminals be connected with a
circuit, the solenoid lying in a shunt circuit will attract the iron cylinder and thereby
swing the oscillating frame upwards on its bearings, overcoming its specific gravity.
The carbons previous to this were out of contact in consequence of the lower position
of the chain wheel and thus of the lower carbon. By the attraction of the iron
cylinder, Figure 4, the flyer S2 of the escapement is released and in consequence of
the specific gravity of the upper carbon holder the two carbon holders approach one
another until the carbons come in contact. Hereby the main current is short circuited,
the circuit solenoid lying in the shunt circuit loses its action, the case.descends, the
lower carbon also descends with it and the arc is struck. Simultaneously with the
sinking of the frame the pendulum disc is retained by the lever tongue u' and an
equipoise is then established between the specific gravity of the frame d and the force
of attraction. of the solenoid until by the burning away of the carbon, the latter in
consequence of the shunt circuit current becoming stronger is again overcome and the
escapement is again released.
The diminution of weight which the lower carbon holder undergoes by the burning
away of the lower carbon is compensated for by a chain Z having one end fixed on the
lamp frame and the other on the lower carbon holder, so that the lower carbon holder
has to draw the chain upwards with it.
A pneumatic brake or buffer a in combination with the oscillating frame diminishes
the backward movement arising by the regulation.
The arc lamp for alternating current hereinbefore described may be also employed
for constant current with a suitable different winding of the solenoid.
The disc a carrying the regulating mechanism is not as hitherto directly connected
to the carbon guide bars or indirectly thereto by the insertion between of fixed
insulating discs, but the carbon frame is mounted on a special plate a² and a plate a¹ is
preferably further inserted between the said plate a² and the plate a. The plates or
discs a, a, a², are firmly held together at suitable distances apart by means of three
or more insulated bolts z.
Between the upper and lower discs a, a² an insulated chamber or space is thus
formed, which is divided into two small insulating spaces lying one over another by
the insertion of the disc a¹. These spaces are either immediately connected with the
outer air so that air inay freely circulate between the discs and can equalize any
increase of temperature of the same, or they are filled with bad conductors of heat.
By this means the regulating mechanism and more particularly the solenoid of the
electro-magnet are withdrawn from the action or influences of the temperature of
the arc and thus the formation of deposits in the regulating chamber is guarded
against, such deposits having hitherto taken place in lamps burning in the open air
or in cool chambers or spaces more particularly. Such moisture deposited on the
regulating mechanism very deleteriously affects the working of the same. The bolts z
serving for connecting the discs a a¹ a² consist preferably of materials which are bad
conductors of heat but may also be formed as insulated electric conductors in order to
effect the supply of current to the carbons independent of the regulating mechanisın
merely through the bars or frame of the lamp. The passing over of the chain which
regulates the movements of the carbons and also of the shunt circuit wire to the
solenoid and electro-magnets takes place in a manner secure from the outer influences
of the weather preferably by using short guide pipes.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, 1 declare that what I claim is :-
1. The improvement in electric arc lamps which consists in the regulating mechanism
and the bars for guiding the carbons being mounted on separate discs (a a²) insulated
from one another by means of an air space or substances which are bad conductors
of heat and in the alteration of resistance of the solenoid which arises on the

page_text: penetration of the iron core into the regulating solenoid being diminished to a
minimum, permitting an even working of the lamp by the iron cylinder (n) which
is drawn into the solenoid on the lamp being regulated, passing over a fixed iron
cone (m) projecting into the solenoid, whereby the resistance of the solenoid during
the working is maintained approximately constant in consequence of a countercurrent
being produced which is strong from the commencement and only alters very
inconsiderably with the attraction of the iron cylinder substantially as hereinbefore
set forth.
2. A form of construction of the arc lamp herein described in which the stopping
and starting of the regulating mechanism is effected by means of an escapement
lever (u) having a tongue (u'), which lever is capable of oscillating on a fixed point (u²)
and which tongue on the lever being carried along by the regulating mechanism and
caused to oscillate during the regulation undergoes a radial and so far relative adjust-
ment to the pendulum disc (S) of the said regulating mechanism that it can arrest a
flyer (S2) mounted on the pendulum disc in the middle of its course of oscillation at
each highest position of the pendulum axis, substantially as described.
3. The general construction and combination of parts taken as a whole, forming the
improved arc lamp substantially as hereinbefore described and illustrated.
Dated this 23rd day of April 1897.
WM. P. THOMPSON & Co.,
Agents.