IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1885

page_text: I HAMILTON WELDON PENDRED of Crohill Freshford, Kilkenny Ireland, Civil
Engineer do hereby declare the nature of my invention for IMPROVEMENTS IN
ELECTRIC ARC LAMPS to be as follows
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These improvemts refer to the lamp patented by me, No 3210 Feb 13th 1884
Instead of putting the cord carrying the carbon holder inside the holder as therin
described I put it outside, and I pass the rod and cord through a packing of cloth
or felt when they pass through the bottom plate of the lamp to prevent dust
entering the lamp For the brake wheel and second wheel in the cage I substitute
a 'scape wheel and pallets. On the pallet arbour I mount a balance wheel or so
much of one as may be required, the circumference of which is coincident with but
in a different plane from the centre of the main wheel on which the cage swings,
and I control the action of the escapement, and the, and the movement of the
carbon holder by means of a brake applied to the edge of the balance wheel just at
this point, which brake is controled by a spring, and a magnet or solenoid core
which last is actuated by the shunt current The solenoid through which this
current flows having a high resistance, when main current becomes weak by the
burning away of the carbons the shunt current becomes strong and drawing on the
solenoid core the pull of the spring 18 overcome, the brake is taken off and the lamp
feeds I use a cut out of any simple well known form applicable to are lamps, and
I send the current thus cut out through a resistance consisting of a coil preferably
of iron wire bung in a tube open at top and bottom passing through the top and
bottom plates of the lamp so that a current of air flows through the same and and
tends to keep the wire in the tube cool

page_text: I HAMILTON WELDON PENDRED of Crohill, Freshford, Co Kilkenny Ireland,
Civil Engineer do hereby declare the nature of my 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 refers to a patent granted to me No 3210, dated February 13th
1884 Instead of putting the cord carrying the carbon holder inside the bolder
I put it outside, and I pass the bolder and the cord through an elastic picking, to
exclude dust, at the point where they pass through the bottom plate of the lamp
For the brake wheel and second wheel in the cage, I substitute a 'scape wheel and
pallets On the pallet arbour I mount a balance wheel, or so much of one as may
be required, the circumference of which 18 coincident with, but in a different
plane from the centre of the main wheel on which the cage swings, and I control
the action of the escapement and the descent of the upper carbon holder by means
of a biake which is controled by a spring pressing the brake against the herin-
before mentioned balance wheel just at the point in its circumference coincident
with the centre pivot on which the cage swings I employ a magnet or solenoid
in a shunt circuit to take the brake off and permit the lamp to feed The shunt
solenoid having a high resistance, when the main current becomes weak by the
burning away of the carbons, the current in the shunt becomes strong, and drawing
on the solenoid core, the pull of the brake spring 18 overcome, the brake is taken
off and the lamp feeds A cut out is fitted to the lamp, and I send the current cut
out through a resistance consisting of a coil of wire which may be placed in a tube
open at both ends and passing through the top and bottom plates of the lamp so
that a stream of air may ascend past the wire and keep it cool
In order that the nature of my said invention of improvements in Electic Arc
Lamps may be better understood, I have appended a sheet of drawings illustrating
the construction of a double lamp made according to my invention
The same
letters illustrate the same parts in all the figures
Fig 1 is a front view Fig 2 is an end view Fig 3 is a plan Fig 4 13
a diagram showing the method of wiring the lamp Fig 5 18 a section of the cord
drum, showing the way in which the cords are secured In the figures, A is the
lamp frame consisting of two circular plates kept apart by distance rods and nuts M
The cage C is constructed as described in the patent specification No 3210 1884 and
need not be described here. The two lower carbons are carried in any convenient
way such as that shown in Figs 1 & 2 On the axis of the main wheel is a barrel R,
to which is secured a rachet wheel as described in the specification No 3210 1884
To this barrel are secured in any convenient way, as for example that shown in
Fig 5, the ends of two cords N P The cord N is fixed by its lower end to a ring
in the upper carbon holder as shown in Fig 1 The upper end of the cord P 1s
secured to a spring Q hooked on to the top end of the carbon holder B
spring keeps the cords tight They are coiled in opposite directions on R so that
when the rod is pushed up by hand P uncoils from R while N coils on it and
This

page_text: when B descends N uncoils while P coils H is the solenoid in the main circuit for
striking the arc as described in specification No 3210, 1884 D is a 'scape wheel
with about 33 teeth, E are the pallets, F G is a segment of a balance wheel
secured on the pallet arbour, G is the brake consisting of a bent wire secured to
the axis
V At the other end of V is a straight wire J to the end of which is hooked
the small core of soft iron seen inside the shunt coil I K is a very elastic spring
supported at its upper end by a screwed rod and nut L By referring to Figs 2 & 3
it will be seen that I use a second barrel R R This, and the carbon holder proper
to it, are provided with cords similar in all respects to those just described
There
is however no cage to this barrel and the wheel C C is only a plain disc without
teeth carrying a click
The action of the lamp is as follows Both caibon holders B, BB Fig 2 being
raised by hand, the insulated click 4 Fig 2 falls into a hole in the side of one
carbon bolder and pevents its descent The current being established will pass
through the free carbon holder, and the arc will be struck, when the are has burned
to the requisite length The brake G which up to this time pevented the oscillation
of F by pessing againt it will be pulled off by the increasing force of the shunt
current in I The escapemt being then free, will work and allow the top carbon
to descend a little, when the current being weakened in I the spring K will once
more force G against F and stop the feed This process is repeated at intervals until
the first pair of carbons are all but burned out At this juncture the collar 10
on the frst rod B, comes in contact with the end of the wire 9 A current ime-
diately flows down this and by means of the light arm 6 serw 7 and branch wire 1
through the electro magnet 3 This instantly attracts the armature above, over-
comg the force of the spring 5 This pulls 4 out of the hole in B B and permits
its descent. The arm 6 is transferred from the screw 7 to the screw 8 and there is
only a momentary break in the current, which is now all cut out of the lamp, and
passing through the resistance coil R¹
From thence it goes on to the other lamps
in circuit, as no current passes through the main solenoid H The end E of the
cage C drops, and the discharging pin T coming in contact with J presses it down,
takes the brake off F and permits both bariels R & R R to revolve The carbon
holder B can descend no further being kept up by the collar 10 and wire 9, but the
holder B B being set free will run down, until it lets the top carbon touch the
bottom one The resistance being very small while the carbons are in contact,
the current at once leaves the cut out circuit through 10 9 8 6 3 & R¹ and being
restored in H the arc 18 struck and the carbons in B B and its negative holder
begin to burn, at the monent these came into contact, the current being cut out
of 3 the armature was released, but 4 now falls not into a hole, but agant the
rod B B and the arm 6 cannot come againt either 7 or 8, and the current is
confined to the carbon holder B B Thus the second set of carbons take up the
work of lighting
It will be understood that R and R R are united by the coupling box S which
fits on two squares on the ends of the spindles of R & R R
While the first pair
of carbons are burning, the disc CC revolves as B feeds, the click fixed on CC
slipping over the teeth in the rachet wheel, When the second pair of carbons
come into operation as just herinbefore explanied the wheel X revolves, while its
nachet wheel and barrel R remain at rest the click slipping over the teeth in the
rachet wheel
It is well known that if a lamp is set to burn with a certain length of arc, say,
one eighth of an inch long, with a current of, say, 12 amperes, if the current is
increased to, say, 13 or 14 amperes the resistance of the arc is diminished, the
current in the shunt circuit I is reduced, and the lamp will burn with a much longer
arc, because the tension of the spring K once adjusted by the screw L is constant
To get over this difficulty, when the current is variable from any cause, as from
putting more or less lamps in circuit, I put in a small subsidiary solenoid in the
main circuit, or in a branch thereof, which acts on a core suspended from an
extension of the rod J or the equivalent of said extension, this core will then pull

page_text: with and aid the solenoid core in I, and produce such an equilebrun that the length
of the are will remain constant, although the current varies Because when the
main current augments, the pull of the subsidiary solenoid will increase in the same
ratio that the pull of I diminishs.
The coil I should not have a greater resistance than 250 ohms, and the core in it
should not be more than one inch long, and three sixteenths of an inch diameter
To avoid complicating the drawings no wires have been shown in Figures 1, 2
01 3 Fig 4 shows the wiring of the lamp in a way which will be readily under-
stood by electricians without description H is the main solenoid which strikes the
arc. R¹ is the resistance coil in the cut out I is the shunt, feed, solenoid. 31s
the electro magnet in the cut out. 10 18 the collar on B 9 is the wire to the brass
plate, on the woodn stand of the electro magnet 3, in which are set the screws 7 & 8
against the heads of which the arm 6 makes contact
I construct single lamps precisely as herinbefore described, and illustrated by
Fig 1
The cut out and second carbon holder with its appurtenances being
suppressed as will be readily understood by Electricans, any convenient and well
known form of cut out may be used in this case to take up the current and pass it
on, when the lamp is extinguished from any cause, while its fellows in the series
are still running
As I make no claim to a cut out in a single lamp I do not
describe one
In some cases, I employ in lieu of the escapement herein before descrebed, a brake
wheel against the flanged rim of which the brake G presses. The wheel D is in
this case a spur wheel diving a pinion, on the axis of which the flanged brake
wheel is mounted, said brake wheel then performing the functions of the segment
of a balance wheel F G.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim 18
1st The construction of electric are lamps substantially as described in the
preeding specification and sheet of di wings accompanying the same
2d The use of a brake for controling the motion of the carbons and acting on an
escapement, or on the rim of a brake wheel or the equivalent of either, at a point
coincident with, but in a plane different from, the main axis on which the cage or
ats equivalent swings, for the purpose of striking the arc.
3d The use of the main current, or a portion thereof, to aid the high resistance
solenoid in a shunt circuit to control the movement of the carbons as described in
the pieceding specification I do not make a general claim to the use of a portion
or the whole of the main current for this purpose purpose, but only to the use of it
substantially as herein before described