Improvements in the Construction and Working of Electric Arc-lamps.
Year: 1895

page_text: Date of Application (in United Kingdom), 23rd Aug., 1895
Complete Specification Left, 19th May, 1896-Accepted, 15th July, 1896'
PROVISIONAL SPECIFICATION.
Improvements in the Construction and Working of Electric
Arc-lamps.
We, LA SOCIÉTÉ LES FILS D'ADOLPHE MOUGIN, of Hericourt, in the
Department Haute Saone, in the French Republic, Mechanical Engineers, do
hereby declare the nature of this invention to be as follows:-
This invention relates to uni-focal electric arc-lamps, and is designed to maintain
the light at a constant degree of intensity; the lamp being, moreover, adapted for
working with a continuous or with an alternating current.
In order to render the following explanations as clear as possible, we will
describe, by way of example, our improvements as applied to an arc-lamp working
with a continuous current.
The regulating mechanism rests on an upper supporting plate, to which are
fixed two dependent rods or tubes connected at their lower extremities by a
suitable cross-bar. Upon these two rods or tubes the carbon-holders are arranged
to slide up or down.
The adjustment of the carbon-holders nearer to or farther from each other is
effected by means of vertically arranged screwed spindles having right and left-
hand threads thereon; the rotation whereof causes the carbon-holders to approach
towards or recede from each other according to the direction of rotation of the
Ecrewed spindles. These screwed spindles are in alignment; the lower end of the
screw pertaining to the upper carbon-holder entering the upper end of the screw
pertaining to the lower carbon-holder, the latter screw being provided with a hole
for its reception; and a slot or slots being formed in the side of the hole for a pin
carried by the entering end of the screw pertaining to the upper carbon-holder to
work in, whereby both screws are caused to rotate in unison;
the rotary
movement being imparted thereto by the motor of the lamp as hereinafter
explained.
The screws are not threaded in the same direction for the reason that when
rotating in unison they must operate so as to bring the carbon-holders towards, or
cause them to recede from, each other. The said screws are also not formed upon
a continuous rod, but they are capable of moving vertically the one in relation to
the other by means of the pin on the one working in a slotted recess in the other;
this being indispensable, in order that the abrupt separation of the carbons at the
desired moment, in view of the formation of the are may be effected. Instead of
using right and left-hand screws and connecting them in the manner indicated, we
may employ a train of gearing; a bevel-wheel being placed on the lower end of
the screw pertaining to the upper carbon-holder and a second bevel-wheel on the
upper end of the screw pertaining to the lower carbon-holder; these two bevel-
wheels gearing with a third bevel-wheel placed between them, so that on the screw

page_text: pertaining to the upper carbon-holder turning, the other screw will be caused to
turn in a reverse direction; this arrangement providing for the use of screws
having their threads inclined in the same direction. Or, the screws, in lieu of
being aligned, may be placed alongside, or parallel with, each other.
The carbon-holders are divided into two parts, each part being distinct,
namely the carbon-holder, properly so-called, and the support therefor.
:
The support for the upper carbon-holder consists of a bifurcated piece sliding
upon one of the dependent rods or tubes before referred to, whereby the carbon-
holder is guided in its vertical movements. The regulating screw passes through
the solid end of this bifurcated piece and against this screw a half-nut is forced by
the action of a spring; this nut being fixed to the end of a rod which terminates
in a cross-pin working in slots in the bifurcations.
Thus it will be seen that, by withdrawing the cross-pin, the nut will be released
from engagement with the screw, thereby permitting the movement of the carbon-
holder by hand, if necessary, along the screw. When the cross-pin is allowed to
return to its normal position, the nut is again brought into contact with the screw
through the pressure exerted by the spring. The carbon-holder, properly
so-called, which is composed of a socket of rectangular section, is provided with
notches in the upper side; these notches being placed between the bifurcated
piece; the socket being secured thereto by means of a tightening screw, which
enables the prongs or sides of the said bifurcated piece to be brought towards each
other; the screw forcing them to compress between them the notched part of the
carbon-holder, which is thus kept in position. If the tightening screw be slightly
loosened, the carbon-holder can either assume a rotary movement about the axis
of the tightening screw, or it can be slightly moved from right to left or from left
to right, thereby permitting the rapid centring of the carbons. The carbon is
inserted into a rectangular socket in which it is held by means of a fastening
screw. The arrangement of the carbon-holder for the lower carbon is exactly
the same as that of the upper carbon-holder, with the exception that an insulating
plate is interposed between the carbon-holder and the socket of the upper carbon,
and which does not exist in connection with the lower carbon-holder, because, as
will be seen later, the lower carbon must be in electrical connection with the
mechanism of the lamp while the upper carbon must not.
The supporting plate carries two upwardly projecting rods, one of which, is
insulated from the said plate while the other is in electrical contact therewith.
These two rods serve, on the one hand, to conduct the current to and from the
lamp, and, on the other, hand, to hold the cap of the lamp against the supporting
plate by means of nuts; the ring for suspending the lamp being placed between
the said rods. The rod which is insulated from the supporting plate is also
insulated where it passes through the cap of the lamp.
The organic parts, which constitute the mechanism, properly so-called of the
lamp, comprise
1. The motor, intended to cause the adjusting screws to turn and consequently
to bring the carbons closer together in proportion as they wear out.
2. An electro-magnet of coarse wire, intended for the direct and instantaneous
formation of the arc.
3. A fine wire regulator for governing the action of the motor which operates
the adjusting screws.
We will now proceed to describe these parts in detail separately; and then we
will study the working of the lamp generally.
The motor which we have adopted is composed of five bobbins respectively
placed on a plate, which may be circular or in the form of a regular pentagon, in
the centre of which plate, the spindle constituting the axis of rotation of the
motor is situated. The armatures are arranged at points diametrically opposite
each other and at an equal distance from the axis.
Over the motor, the collector and two brushes are placed, the latter being

page_text: diametrically opposite each other, and electrically connected so that there is no
need to take into account the difference of voltage which may occur between the
brushes.
The wires coiled in the five bobbins are connected at their lower part with the
lamp, and each of the upper ends of the wires of the bobbins abuts upon a
segment of the collector.
This collector is formed of five equal segments, to each of which one of the
wires of the bobbins is attached.
The brushes are connected by means of a wire, with a spring and with the
lower part of a fine wire regulator by means of another wire.
The spindle of the motor is provided at its lower end with an endless screw
which gears with a worm-wheel fast on a shaft furnished with an endless screw
meshing with a horizontal worm-wheel mounted on the upper prolongation of the
adjusting screw pertaining to the upper carbon-holder, whereby that screw is
caused to revolve. At the upper extremity of the said adjusting screw is provided
a plate, having two holes formed therein for the passage of two short rods
depending from the boss of the horizontal worm-wheel. Upon the rotation of the
horizontal worm-wheel, the adjusting screw is turned through the medium of the
two short rods which take into the holes in the plate fixed to the upper part of
the said adjusting screw.
A coarse-wire electro-magnet is traversed by the current upon its entering the
lamp. For that purpose it is connected by a wire with one of the upwardly
projecting rods; the other end of the coarse wire coiled on the bobbins of the
electro-magnet being connected by another wire with the upper carbon. The
latter wire ends at the lower part of the upper carbon-holder which is insulated
from the lamp.
Underneath the electro-magnet is placed a metal plate or
armature which is attracted by the electro-magnet when the latter is traversed by
a current. The adjusting screw pertaining to the upper carbon-holder is drawn
upwards by the horizontal worm-wheel, but the upper part of this screw passes
with gentle friction through the boss of the said worm-wheel and screws itself into
a nut, situated beneath the armature, in such a way that, on the one hand, the
upper portion of the adjusting screw can turn without involving in its rotation the
armature, and, on the other hand, the armature, in rising, can likewise raise
the adjusting screw to effect the abrupt separation of the carbons.
A spiral spring is threaded on the adjusting screw towards its upper extremity,
one end of the spring abutting against the under side of the supporting plate, the
other acting against a nut or washer on the screw; the object being to prevent
the screw rising during the normal working of the lamp. This spring may,
however, be placed over the plate or armature between the two bobbins, or it may
be arranged to rest on the plate.
The fine-wire regulator before referred to comprises a solenoid coil consisting of
a bobbin, on which twenty layers of fine wire are coiled. In the centre of this
bobbin is placed a metal core, above a pivoted plate. This plate carries a counter
weight, the object whereof will be hereinafter explained. The pivoted plate,
according to the position it occupies, can touch one of the two short iods, insulated
from the lamp and connected by a wire towards the bottom of the 20th coil of
fine wire on the bobbin. The insulated rod is connected by a wire with one of the
ends of the fine wire of the bobbin. At the end of the 19th layer of fine wire,
which end is at the bottom of the bobbin, the fine wire divides into two; one wire
ends at the brushes of the motor, and the other, the twentieth layer, which coils
itself upon the bobbin in an upward direction, and the end of which is sunk in the
upper plate, is in connection with the lamp. In the present example, we have
supposed that the first nineteen layers of wire were blended into a single layer.
The number of layers of fine wire has, however, nothing absolute about it, and it
depends upon the resistance which the regulator is to have. From the twentieth
layer and towards the bottom of the bobbin, a wire starts, as we have said above,
and ends at the short rods; and also towards the bottom of the twentieth layer,

page_text: there starts a wire which ends in a spring, which is in connection with the lamp so
long as the plate or armature of the coarse-wire electro-maguet is not attracted.
This plate, carries a pin which, when the plate is not attracted by the electro-
magnet, is in contact with the said spring, but which is out of contact therewith
when the plate is attracted by the electro-magnet.
Besides the organic parts just described, the regulating mechanism of the
improved lamp also comprises a rod which is disposed within one of the dependent
connecting rods or tubes forming the guides for the carbon-holders. This rod
carries near its lower extremity a pin situated a little below the highest level
capable of being reached by the lower carbon-holder. The upper extremity of
this rod, at norinal times, is maintained a short distance from a horizontal spring
secured to a post attached to the supporting plate, but insulated from the lamp.
This post is connected by a wire with the brushes of the motor and the object
whereof will be seen later, in the description of the action of the motor.
Having specified the organic parts of the improved lamp, we will now proceed
to describe the action thereof.
The carbons having been fixed in the respective carbon-holders and regulated,
as regards position, are brought into contact with each other. This latter
operation is effected by moving the carbon-holders by hand, as hereinbefore
explained.
This being done, we will suppose that the lamp is placed in a circuit traversed
by an electric current. The current enters the lamp by the insulated rod projecting
from the upper side of the supporting plate, passing by way of a conducting wire
through the electro-magnet coil to the lower insulated portion of the upper
carbon-holder. The current passes into the lower carbon and from there it
proceeds through the mechanism of the lamp to the other rod projecting from
the upper side of the supporting plate. As soon as the electro-magnet is traversed
by the current, the plate or armature in connection with the adjusting screw or
screws of the carbon-holders is attracted, and the carbons which were originally
in contact are abruptly separated, the electric arc is formed, and the lamp becomes
operative.
We will now explain the operation of the motor, situated in the circuit of
derivation, which is governed by the regulator before referred to, the object of
which is to effect the bringing the carbons closer together in proportion as they
are worn away by the electric arc.
The current entering the coarse-wire electro-magnet, from the insulated rod
before referred to, passes by way of a wire into the fine wire coiled on the
regulator, and, after traversing the nineteen coils of wire, the current, on the one
hand, is conveyed to the brushes of the motor through a wire, and, on the other
hand, to the lamp by way of the twentieth coil on the regulator, provided that
the pivoted plate is not in contact with either of the short rods. Now the pivoted
plate does not touch either of these rods when the current which passes through
the regulator is sufficient to give the solenoid core such a magnetisation that the
said pivoted plate is kept vertical in spite of the action of the counterweight,
which tends to make it touch one of the two short rods. Under these circum-
stances, the current, after having traversed the nineteen layers of fine wire coiled
on the regulator, reaches the brushes of the motor and the latter turns, bringing
the carbons towards each other; a very small part of the current passing through
the resistance composed of the twentieth layer of wire of the regulator. The
regularity in the working of the lamp is thereby effected.
If, at a given moment, the resistance of the lamp diminishes, in consequence of
the carbons being brought too close together, the quantity of current which
traverses the regulator or solenoid coil (placed in the circuit of derivation)
diminishes, and consequently the magnetisation of the core becomes less, so that
the pivoted plate, being no longer maintained in a vertical position, touches one of
the short rods. The lamp is thus connected with the last spires of the twentieth
layer of the regulator. At that moment, the eatering current traverses the first

page_text: nineteen layers of wire of the regulator, and then, as before, runs through two
circuits, one of which is always formed by the brushes, the motor and the lamp;
the other, instead of being formed by the twentieth layer of wire of the regulator,
is now only formed by a few spires of that twentieth layer and by the wire which
directly connects those spires with the lamp.
The resistance of this second circuit is much weaker than that of the twentieth
layer of wire, so that the quantity of current which traverses this circuit is much
greater than that which originally traversed the twentieth layer of wire.
Consequently, the quantity of current which passes through the brushes and
the motor diminishes. The motor therefore turns less rapidly, the resistance of
the arc gradually increases, the magnetisation of the regulator core regains the
necessary strength to bring the pivoted plate back to a vertical position and the
lamp again acts as at the outset.
To explain the part played by the regulator, the current of derivation, which
comes from the insulated rod projecting from the upper side of the supporting
plate and goes to the lamp, may, before reaching the motor, traverse two circuits,
one of which comprises the motor, and the other contains a resistance which the
regulator causes to vary, in such a way as to diminish it, when the quantity of
current which is to pass through the motor is to be reduced, and to increase it
when, on the other hand, the quantity of current which is to pass through the
motor to be increased.
When the lower carbon is exhausted, it is desirable that the motor should stop
automatically, in order not to burn the carbon-holder. To effect this, the lower
carbon-holder, towards the end of its upward travel, comes into contact with the pin
carried by the rod, working in one of the depending connecting rods or guides, and
lifts it. The upper end of this rod then makes contact with the horizontal spring.
This rod forms part of the lamp; the spring being connected with the brushes in
such a way that all the current which reaches the brushes, in order to go through
the motor to the lamp, passes through the connecting wire, the resistance of which
is nothing, as compared with that of the motor. Current will now cease to flow
through the motor, which will consequently stop; the result being a break in the
formation of the arc. Thus warning will be given that it is necessary to put in
new carbons.
We have hitherto assumed that the carbons were brought into contact with
each other before introducing the current into the lamp. Were it otherwise, the
current at the outset would not pass through the electro-magnet, but would pass
entirely through the circuit of derivation to reach the motor, which would revolve
very rapidly, and bring the carbons together. As soon as the latter come into
contact, part of the current would pass through the electro-magnet and the carbons,
and thence to the lamp, the arc would be produced and the action brought about
as above explained.
The carbons, however, not being in contact, nearly all the current would pass
through the motor, only a very small portion of the current passing through the
twentieth layer of the regulator. Under these circumstances, large sparks would
be produced in the brushes and it is in order to avoid this inconvenience that we
have arranged the circuit formed by the wire and spring, which is of less resistance
than the twentieth layer, the effect of which is that so long as the carbons are not
in contact, or, in other words, so long as the current does not pass through the
electro-magnet, a large part of the current passes through the insulated rod for
the entering current, the regulator, the connecting wire therefrom, the spring, and
the lamp. The motor in this case would not be traversed by the whole of the
current and sparks would not result.
The regulator may take different forms without altering the principle upon which
it is based. For instance, the core, whereby the pivoted plate is attached, may
be connected with the plate itself instead of being separate. At normal times,
when the lamp is acting regularly, the core preserves the plate in a vertical
position, but if the quantity of the current passing through the regulator

page_text: diminishes, the core rises and causes the plate to touch one of the short rods, as in
the previously described arrangement.
According to another modification, the regulator may be constructed as an
electro-magnet with two bobbins, but the action would be similar in both
arrangements, as regards the circuits formed by the fine wire on the regulator.
The lower end of the adjusting screw pertaining to the lower carbon-holder
passes through the cross-bar and is secured by nuts, which permit vertical move-
ment of the two aligned screws. The distance between the two carbons at the
moment of the production of the arc may be regulated by hand. If, by means of
the nuts at the lower extremity of the regulating screws we cause the said screws
to rise, the armature plate will approach the electro-magnet, and, when this plate
is attracted by the electro-magnet, the screws will separate very slightly. By
causing the said screws to descend by means of loosening the nuts at the lower
extremity the opposite effect will be produced. The nuts on the lower extremity
of the screws also permit of reducing or increasing the distance between the
carbons while the lamp is working.
The advantage presented by the employment of the herein described fine-wire
regulator is that it can be regulated before delivery from the works, and placed
on the lamp without subjecting the lamp itself to any special regulating. It may,
if desired, be placed at a distance from the lamp, it being understood that it would
be as effective when removed as when placed in the lamp itself.
The several advantages of our invention are:-
1. Reduction in the weight of the lamp, being about 2500 kos.
2. Absolute fixity of focus.
3. The carbons are brought together in a continuous manner.
4. The regulation of the carbons is effected at will and instantaneously.
5. The length of the arc may be regulated during the working of the lamp.
6. The turning the lamp round for the reversed arc. This being made
practicable by the two short rods between which the pivoted plate above the
regulator works, for if one of these rods is used when the lamp is upright, the
other serves when the lamp is reversed.
7. The lamp works at a minimum tension.
8. Facility of construction for several foci without appreciable increase in
-cost.
9. Absence of all insulation in the mounting. Absolute rigidity.
10. Springs are dispensed with as means for regulating.
11. Intensity variable.
12. The regulator, may be regulated before hand, and transferred from one
lamp to another, without the necessity for any other operation of regulation of the
lamp itself.
As explained at the commencement of this specification, the lamp, as described
above, is arranged to work on a continuous current, but it will be apparent that,
with the necessary modifications in the electro-magnet and in the regulator, the
lamp may be arranged to work with alternating currents.
Dated the 23rd day of August 1895.

page_text: Improvements in the Construction and Working of Electric
Arc-lamps.
We, LA SOCIÉTÉ LES FILS D'ADOLPHE MOUGIN, of Hericourt, in the
Department Haute Saune, in the French Republic, Mechanical Engineers, 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 uni-focal electric arc-lamps, and is designed to maintain
the light at a constant degree of intensity; the lamp being, moreover, adapted for
working with a continuous or with an alternating current.
In the accompanying drawings, we have illustrated our improvements as applied,
by way of example, to an electric arc-lamp working with a continuous current.
Fig. 1 is an elevation of an electric arc-lamp embodying our improvements.
Fig. 2 is a plan of same, drawn, to a larger scale.
Fig. 3 is a vertical section through the plate G, looking in the direction of the
electro-magnet, and drawn to a scale corresponding with Fig. 1.
Fig. 4 shows in elevation and partial section the fine wire regulator detached
from the lamp.
Fig. 5 is a plan (taken on the line 1-2 in Fig. 1) of the upper carbon-holder.
Fig. 6 is a similar view (on the line 3-4 in Fig. 1) of the lower carbon-bolder.
Fig. 7 is a view of the carbon-holder proper detached.
Fig. 8 is an enlarged view illustrating the method of coiling the fine wire
pertaining to the regulator.
Figs. 9 and 10 show alternative constructions of the regulating device.
Fig. 11 is a view, detached and enlarged, showing the means for actuating the
adjusting screws pertaining to the carbon-holders.
Fig. 12 illustrates the means for short-circuiting the lamp and effecting the
stoppage of the motor, whereby, on the carbons becoming exhausted, an alarm is
given and harm to the carbon-holder prevented.
The regulating mechanism pertaining to the lamp rests on an upper supporting
plate G, to which are fixed two dependent rods or tubes A and B connected
together at their lower extremities by means of a cross-bar C. Upon these rods
or tubes, the carbon-holders D and D' are arranged to slide up or down.
The adjustment of the carbon-holders D, D' nearer to or farther from each
other is effected by means of vertically arranged screwed spindles E, E¹, the
spindle E pertaining to .the upper carbon-holder D having a right-hand thread
thereon, while the spindle E pertaining to the lower carbon-holder D¹ is formed
with a left-hand thread. The rotation of the screw-spindles causes the carbon-
holders to approach towards or recede from each other according to the direction
of the rotation of the said spindles. The spindles E, E' are in alignment; the
lower end of the screw E entering the upper end of the screw E' the latter being
provided with a hole for its reception. A slot or slots is or are formed in the side
of the hole in the spindle E¹ for a pin e, carried by the screw E, to work in,
whereby both screws are caused to rotate in unison and to regulate the positions
of the carbon-holders; the rotary movement being imparted thereto by the motor
of the lamp as hereinafter explained.
The screws E, E' are not formed upon a continuous rod, but they are capable of
moving vertically, the one in relation to the other, by means of the pin e on the
one (E) working in a slotted recess in the other (E); this being indispensable, in
order that the abrupt separation of the carbons, at the desired moment, in view of
the formation of the arc, may be effected.

page_text: Instead of using right- and left-hand screws, and connecting them in the manner
indicated, we may employ a train of gearing; a bevel-wheel being placed on the
lower end of the screw E and a second bevel-wheel on the upper end of the
screw E¹; these two bevel-wheels gearing with a third bevel-wheel placed between
them, so that on the screw E turning, the screw E¹ will likewise turn, but in a
reverse direction. In such an arrangement the threads of the screws E and E¹ are
inclined in the same direction. Or, the screws E, E', in lieu of being in alignment,
may be placed along side, or parallel with each other.
The carbon-holders are divided into two parts, each part being distinct,
namely the carbon-holder, properly so-called, and the support therefor.
:
The support D for the upper carbon-holder d is forked or bifurcated at F (Fig. 5),
and at fit is made in the form of a slide which engages with the dependent rod
or tube B, whereby the carbon-holder is guided in its vertical movements. The
regulating screw E passes through the support D and against the screw a half-nut H
is forced by the action of a spring h; this nut being fixed to the end of a rod h¹
which terminates in a cross-pin " working in slots
Thus it will be seen
that, by withdrawing the cross-pin, the nut H will be released from engagement
with the screw E, thereby permitting the movement of the carbon-holder to be
accomplished by hand, if necessary, along the screw E. When the cross-pin "
pertaining to the nut H is allowed to return to its normal position, the nut His
again brought into contact with the screw E and maintained in that condition by
means of the spring h. The carbon-holder d (Fig. 7), properly so-called, and
which comprises a socket of rectangular section, is provided with notches in the
upper side; these notches receiving the forked or bifurcated portion F of the
holder D. I is a tightening screw, which enables the prongs pertaining to
the forked piece F F to be brought towards each other; the screw I forcing the
parts FF to compress between them the notched part of the carbon-holder d,
whereby it is maintained in position. If the tightening screw I be slightly
loosened, the socket or carbon-holder d can either assume a rotary movement about
the screw. I, or it can be slightly moved from right to left or from left to right,
whereby the rapid centring of the carbons may be accomplished. The carbon is
inserted into the socket d and is held therein by means of a fastening screw I¹.
The arrangement of the carbon-holder D₁ for the lower carbon, is exactly the
same as that just described for the upper carbon-holder D, with the exception that
an insulating plate J is interposed between the carbon-holder D and the socket d
for the upper carbon, and which does not exist in connection with the lower carbon-
holder, because, as will be seen later, the lower carbon must be in electrical
connection with the mechanism of the lamp, while the upper carbon must not.
The supporting plate G carries two upwardly projecting rods K and L, one of
which, K, is insulated from the said plate G while the other, L, is in electrical
contact therewith. These two rods serve, on the one hand, to conduct the current
to and from the lamp, and, on the other hand, to hold the cap M of the lamp by
means of nuts and 1; the ring whereby the lamp is suspended being placed
between the rods k and l. The rod k which is insulated from the plate G is also
insulated where it passes through the cap M of the lamp.
The organic parts which constitute the mechanism proper of the lamp, comprise
(1) a motor, N (Fig. 1), for operating the screws E, E', whereby they are turned
and consequently bring the carbons closer together in proportion as they wear out,
(2) an electromagnet O (Fig. 3), of coarse wire, the purpose of which is to effect
the direct and instantaneous formation of the arc, (3) a fine wire regulator P
(Figs. 4 and 8), whereby the action of the motor is governed.
We will now proceed to describe the several parts in detail, and then the
working of the lamp generally. The motor N which we have adopted is composed
of five bobbins respectively placed on a plate which may be circular or in the form
of a regular pentagon, in the centre of which plate, the spindle n, upon which
the motor rotates, is situated. The armatures are arranged diametrically
opposite each other and at an equal distance from the axis. Over the motor, the

page_text: collector and two brushes n" n" are placed, the latter being diametrically opposite
each other, and electrically connected, so that there is no need to take into account
the difference of voltage which may occur between the brushes. The wires coiled
on the five bobbins are connected at their lower part with the lamp, and each of
the upper ends of the wires of the bobbins abuts upon a segment of the collector.
This collector is formed of five equal segments, to each of which one of the bobbins
is attached. The brushes are connected by means of a wire 1 with a spring Q
and with the lower part of the fine wire regulator P by means of another wire 2
(Fig. 2).
The spindle n of the motor carries at its lower end an endless screw which gears
with a worm-wheel n fast on a shaft n, furnished with an endless screw n, meshing
with a horizontal worm-wheel n3 (Fig. 3) mounted on the upper prolongation of the
screw E, whereby that screw is caused to revolve. At its upper extremity, the
screw E carries a plate, having two holes e, formed therein for the passage of two
short rods e, which depend from the horizontal wheel n3. Upon the rotation of
the wheel n3, the screw E is caused to turn through the medium of the two short
rods e, which take into the holes e, in the plate carried by the screw E
(Fig. 11).
A coarse-wire electromagnet O is traversed by the current upon its entering
the lamp. It is connected by a wire 3 with the rod K (Fig. 2); the other end of
the coarse wire coiled on the bobbins of the electromagnet being connected by
another wire 4 with the upper carbon. The wire 4 ends (as shown in Fig. 1) at
the lower part d, of the upper carbon-holder which, as previously stated, is
insulated from the lamp. Underneath the electromagnet O is placed a metal.
plate Oor armature which is attracted by the electromagnet when the latter is
traversed by a current. The screw E is drawn upwards by the wheel ng, but its
upper part passes, with gentle friction, through the wheel n3 and screws itself into
a nut beneath the armature or plate O' and arranged in such a way that, on the
one hand, the screw E can turn without involving in its rotation the plate O¹, and,
on the other hand, the plate O' in rising, can likewise raise the screw E' to effect
the abrupt separation of the carbons.
A spiral spring R is provided at the upper extremity of the screw E; one end
of the spring abutting against the under side of the plate G, whilst the other end
acts against a nut or washer r on the screw E; the object being to prevent the
screw E rising during the normal working of the lamp. This spring may,
however, be placed over the plate O¹ between the two bobbins, or it may be arranged
to rest on the plate O'.
The fine wire regulator P comprises a solenoid coil consisting of a bobbin, on
which twenty layers of fine wire are coiled. In the centre of this bobbin is placed
a metal core p, above which is a plate p₁, pivoted at p₂. The plate p₁ carries a
counterweight P1, the object whereof will be hereinafter explained.
The plate Pi
according to the position it occupies, can touch one of the rods p. (Fig. 4),
insulated from the lamp and connected by a wire 5 towards the bottom of the
20th layer of fine wire pertaining to the bobbin P. The insulated rod K is connected.
by a wire 6 with one of the ends of the fine wire of the bobbin P.
At the end of the 19th layer of fine wire, situated at the bottom of the bobbin,
the fine wire divides into two; whereof one wire 2 ends at the brushes of the
motor, and the other, the twentieth layer, 7 (Fig. 8) which coils itself upon the,
bobbin in an upward direction and the end of which is sunk in the upper plate P',
is in connection with the lamp. In Fig. 8, we have supposed that the first nineteen
layers of wire were blended into a single layer. The number of layers of fine wire
has, however, nothing absolute about it, and it depends upon the degree of resistance
the regulator is required to possess. From the twentieth layer, and towards the
bottom of the bobbin, the wire 5 is taken to the short rods ; and also towards
the bottom of the twentieth layer, there is taken a wire 8, ending in a spring S,.
which is in connection with the lamp so long as the plate O' is not attracted by
the electromagnet O. This plate carries a pin s, which, when the plate is not:
B

page_text: attracted by the electromagnet, is in contact with the spring S, but which which is
out of contact therewith when the plate O' is attracted by the electro-magnet O.
Besides the organic parts just described, the regulating mechanism of the
improved lamp also comprises a rod U which is capable of vertical movement in
the hollow guide A. This rod carries near its lower extremity a pin u situated a
little below the highest level attainable by the lower carbon-holder. The upper
extremity of this rod U, at normal times, is maintained a short distance from a
spring secured to a post Q1 but insulated from the lamp by a plate Q" of
insulating material. This post Q' is connected by a wire 1 with the brushes of
the motor and the object whereof will be scen later, in the description of the action
of the motor.
Having specified the organic parts of the improved lamp, we will now proceed
to describe the action thereof.
The carbons having been fixed in the carbon-holders D and D' are to be first
regulated, as regards position by means of the screws I and brought into contact
with each other. This latter operation is effected by moving the carbon-holders by
hand, as before explained.
This being done, it is supposed that the lamp is placed in a circuit traversed by
an electric current. The current enters the lamp by the insulated rod K and
passes by way of the wire into and through the electro-magnet through the
wire 4 to the insulated portion d of the upper carbon-holder. The current
passes into the lower carbon and from there it proceeds through the lamp to the
rod L. Upon the electro-magnet O being traversed by the current, the plate O
or armature is attracted, and the carbons which were originally in contact are
abruptly separated, the electric arc is formed, and the lamp becomes operative.
We will now explain the operation of the motor N, which is situated in the
circuit of derivation, and which is governed by the regulator P, the object of which
is to bring the carbons closer together in proportion as they are worn away by the
electric arc.
The current entering the coarse-wire electro-magnet O, by way of the insulated
rod K, passes through the wire 6 into the fine wire coiled on the regulator P, and,.
after traversing the nineteen layers of wire, the current on the one hand is conveyed
to the brushes of the motor through the wire 2, and, on the other hand, to the lamp
through the twentieth layer 7 (Fig. 8), of the wire coiled on the regulator,
provided that the pivoted plate p, at the moment is not in contact with either of
the short rods P. Now the pivoted plate p₁ does not touch either of the rods p3:
when the current which passes through the regulator is sufficient to give the core p.
such a magnetization that the plate p, is kept vertical in spite of the action of the
counterweight p¹, which tends to cause it to touch one of the rods p3. Under
these circumstances, the current from the rod K, after traversing the nineteen
layers of fine wire coiled on the regulator P, reaches the brushes of the motor and
the latter turns, bringing the carbons towards each other; a very small part of the:
current passing through the resistance composed of the twentieth layer of wire of
the regulator. Thus regularity in the working of the lamp is obtained.
If, at a given moment, the resistance of the lamp diminishes in consequence of
the carbons being brought too close together, the quantity of current which
traverses the regulator P (placed in the circuit of derivation) diminishes, and
consequently the magnetisation of the core p becomes lower, so that the plate p,,.
being no longer maintained in a vertical position, touches one of the short rods p3.
The lamp is thus connected by the wire 5 with the last spires of the twentieth layer
of the regulator P. At that moment, the current entering by the rod K traverses.
the first nineteen layers of wire of the regulator P, and then, as before, runs.
through two circuits, one of which is always formed by the brushes, the motor and.
the lamp; the other, instead of being formed by the twentieth layer of wire of the
regulator, being now only formed by a few spires of that twentieth layer and by
the wire 5 which directly connects those spires with the lamp. The resistance of
this second circuit is much weaker than that of the twentieth layer of wire,

page_text: so that the quantity of current which traverses this circuit is much greater than that
which originally traversed the twentieth layer of wire. Consequently, the quantity
of current which passes through the brushes and the motor diminishes. The motor
therefore turns less rapidly, the carbons approach each other less rapidly, the
resistance of the arc gradually increases, the magnetization of the core p regains
the necessary strength to return the pivoted plate p, to its vertical position and the
lamp again acts as at first.
To explain the part played by the regulator P, it may be stated that the current
of derivation, which comes from the insulated rod K and goes to the lamp, may,
before reaching the motor, traverse two circuits, whereof one comprises the motor,
and the other contains a resistance, which the regulator causes to vary in such a
way as to diminish it when the quantity of current which is to pass through the
motor is to be reduced, and to increase it when, on the other hand, the quantity of
current which is to pass through the motor is to be increased.
When the lower carbon is exhausted, it is desirable that the motor should stop
automatically, in order not to burn the carbon-holder. To effect this, the lower
carbon-holder, towards the end of its upward travel, comes into contact with the
pin u carried by the rod U and lifts it. The upper end of the rod U then makes
contact with the spring Q. This rod U forms part of the lamp; the spring Q
being connected by the wire 1 with the brushes in such a way that all the current
which reaches the brushes, in order to go through the motor to the lamp must pass
through the wire 1 the resistance of which is nothing, as compared with that of
the motor. No current now flows through the motor, which will consequently stop;
with the result that the formation of the arc ceases. Warning is thus given that
it is necessary to put in new carbons.
out of
It has hitherto been assumed that the bringing the carbons into contact with
each other has taken place prior to the introduction of the current into the lamp.
Were it otherwise, the current, at the outset, would not pass through the electro-
magnet O, but would pass entirely through the circuit of derivation to the motor,
which would revolve very rapidly, and bring the carbons together. As soon as
the latter come into contact, part of the current passes through the electro-
magnet O, and the carbons, and thence to the lamp, the arc is produced and
the action brought about as above explained. If the carbons be
contact, nearly all the current passes through the motor; only a very small
portion thereof passing through the twentieth layer of the regulator. Under
these circumstances, large sparks would be produced in the brushes, and it is
in order to avoid this inconvenience that we have arranged the circuit formed by
the wire 8 and spring S, which is of less resistance than the twentieth layer.
The effect of this is that so long as the carbons are not in contact, or, in other
words, so long as the current does not pass through the electro-magnet O, a large
part of the current will pass through the rod K, the regulator, the wire 8, the
spring S and the lamp. The motor in this case is not traversed by the whole of
the current and sparks would not result.
Referring to Figs. 9 and 10 the regulator P may take different forms without
altering the principle upon which it is based. In Fig. 9, the core, whereby the
pivoted plate p₁ is attracted, is replaced by a bar connected with the plate itself.
At normal times, when the lamp is acting regularly, the core p preserves the
plate pi in a vertical position, but if the quantity of current passing through
the regulator diminishes, the core rises and causes the plate p₁ to touch one of the
rods p3, as in the previously described arrangement.
According to another modification, shown in Fig. 10 the regulator may
be an electro-magnet with two bobbins; the action being similar to the last
mentioned arrangement, as regards the circuits formed by the fine wire on the
regulator.
The lower end of the screw E¹ passes through the cross-bar C and is secured
by rowel nuts E", whereby the vertical adjustment of the screws E E' may he
accomplished. It will thus be seen that the distance between the two carbons at

page_text: the moment of the production of the arc may be regulated as desired by hand.
If, by turning the nuts E" the screws E El are caused to rise, the upper end of
the screw E, i.e., the plate O¹, will approach the electro-magnet O, and when this
plate O is attracted by the electro-magnet O, the screws E E¹ will separate
very slightly. Similarly by causing the said screws E E¹ to descend the opposite
effect will be produced. The nuts E also permit the operation of reducing or
increasing the distance between the carbons to be effected while the lamp is
working.
The employment of the fine-wire regulator herein described presents the
advantage of being capable of regulation before delivery from the works, and
that it can be placed on the lamp without the lamp itself being subjected to any
special regulating. Moreover, if desired, it may be placed at a distance from the
lamp, as it will be readily understood that it would be as effective in regulating
the lamp when removed therefrom as when placed in the lamp itself.
The several advantages of our invention are:-
1. Reduction in the weight of the lamp being about 2,500 kos.
2. Absolute fixity of focus.
3. The carbons are brought together in a continuous manner.
4. The regulation of the carbons is effected at will and instantaneously.
5. The length of the arc may be regulated during the working of the lamp.
6. The lamp may be turned round for the reversed arc; this being made
practicable by reason of the two rods pa, for if one of these rods be used when
the lamp is upright, the other one serves when the lamp is reversed.
7. The lamp works at a minimum tension.
8. Facility of construction for several foci without appreciable increase
in cost.
9. Absence of insulation in the mounting and perfect rigidity.
10. Absence of springs as means for regulating.
11. Intensity variable.
12. The regulator, regulated beforehand, may be transferred from one lamp
to another, without necessitating any other regulating operation of the lamp
itself.
As previously explained, the improved lamp is herein described as working on
a continuous current; but it will be apparent that, with the necessary modifications
in the electro magnet O and in the regulator P, the lamp may he worked with
alternating currents.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we claim :-
1. The improved electric are lamp constructed or operating substantially as
herein described with reference to the accompanying drawings.
2. In an uni-focal arc-lamp, with constant intensity of light, the carbon holders
of which are moved by the rotation of screws, the employment for imparting
rotation to the screws, of a motor interposed in the circuit of derivation, the said
motor being formed by an uneven number of bobbins each of the wires coiled
thereon being connected, at the lower end, with the lamp and, at the upper end,
with a segment of the colle tor, the number of segments of such collector, (each
of which is insulated from the other and against which the brushes rub) being
equal to that of the bobbins; the current of derivation entering the motor through
the brushes and going out through the lamp, substantially as described.
3. In an electric arc-lamp of the type herein described, the combination, with
the motor claimed in the preceding claiming clause, of a fine-wire regulator P,
placed in the circuit of derivation, and comprising a bobbin whereon are coiled
n layers of fine wire, the nth of which is connected with the lamp, while 'the n-1th
is connected with the motor, the bobbin having in its centre a metal core, the
end of which is in juxtaposition to a plate 7 provided with a counterweight pl,
said plate maintaining a vertical position so long as the current passing through

page_text: the regulator is sufficient to cause the metal core to attract the plate; the said
plate coming into contact with a rod p, when the current passing through the
regulator diminishes, the object of the contact of the plate p₁ with the rod pa
being to place the last spires of the nth layer of wire in direct connection with
the lamp, in order to produce a circuit of less resistance than the nth layer of
wire itself, with the result that the quantity of current which reaches the motor
through the end of the n- -1th layer of fine wire is diminished.
4. The employment of the regulator, particularised in the third claiming clause
in the prevention of sparking on the brushes, the whole of the current passing
through the brushes in the event of the lamp being set to work without the
carbons being in contact; such utilisation being obtained by the addition of a
wire connecting the last spires of the nth layer of fine wire with a spring S in
contact with the lamp so long as the arc is not formed, so that, while the arc is.
not produced, part of the current passes through the wire which connects the
last spires of the nth layer of wire of the regulator directly with the lamp.
5. In an electric arc-lamp such as herein described, the automatic formation of
a short circuit, whereby the motor is instantly stopped when the carbons are used
up, this short circuit being obtained by a rod U, which, upon being raised by the
lower carbon-holder so soon as the latter reaches the summit of its course, comes
into contact with the spring Q, insulated from the lamp and directly connected.
with the brushes of the motor, and causes the current, instead of passing through.
the motor to reach the lamp, to pass through the circuit of smaller resistance.
closed by the contact of the rod U with the spring Q.
6. In an electric arc-lamp such as herein described, the combination with the-
screws E E¹, which produce the movement of the carbon-holders, of rowel
nuts E for enabling the screws E E' to be operated by hand, substantially as
Specified.
Decifcu.
Dated this 14th day of May 1896.
For the Applicants,
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent..