Year: 1887

page_text: Date of Application, 5th July, 1887.
Specification Accepted, 19th Aug., 1887.
I, Frederic de WOLFFERS, of 47 Boulevard Beaumarchais, Paris, in the Republic
of France, Electrical 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 :-
This invention has for its object the production of the Electric Light by means of
an arc lamp presenting the following characteristics, namely:-
The resistance of the Electric arc is maintained constant.
The luminous focus or centre may either be fixed or moveable and following the
consumption of the carbon rods.
The lighting and re-lighting of the lamps are effected automatically.
The lamp may be used for the production of a large or small illuminating power.
The lamps can be worked either singly or connected in series or in multiple are.
And in order that my said Invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed Sheet of drawings, the same letters of reference indicating
corresponding parts in all the figures.
Figure 1 of the accompanying drawings is a diagram illustrating the principle of
action of the lamp.
Figure 2 is a corresponding plan of the brake mechanism.
Figure 3 is a diagram shewing the electrical connections of the parts in the lamp.
Figure 4 is an elevation of a lamp constructed according to my Invention.
Figure 5 explains the construction of the brake hereinafter referred to and its
arrangement relatively to the carbon-carrier or holder and the coils which surround
the said carrier.
Figure 6 is a sectional plan of the brake and its armature.
Figures 7, 8, 9, 10, 11 indicate various modes of arranging the different parts of
the lamp as hereinafter described.
In Figure 1 of the annexed drawing A is an iron rod carrying the upper carbon of
the lamp and B B are two coils surrounding the said rod which is free to move
longitudinally in the interior of the said coils. The wires of these coils are so wound
that on the passage of a current a magnetic pole is produced in that portion of the

page_text: rod A which is situated between the two coils. A solenoid C placed in a shunt
around the arc is provided with a soft iron core D to which is attached a rod E
carrying the lower carbon. To the upper portion of this core is fixed a short rod F
carrying a moveable contact G corresponding with a fixed contact O and the core D
and its attachments are suspended from a spring H.
I (Figures 1 and 2) is a pivotted arm acting as a brake, being connected to an
armature K and to a spring L, which latter tends to press the brake against the rod A.
The tension of the said spring can be regulated by a screw M and a screw N serves
to limit the extent of movement of the brake.
The brake arm I is formed by a plate of copper or other nonmagnetic substance
pivotted on an axis P. The spring L tends to press this brake against the iron carbon
carrier A with such force as to arrest the descent of the latter. The armature K
attached to the brake as aforesaid is attracted by the iron rod A when a current
circulates in the coils B B', and tends to move the brake away from the rod. The
screw N limits the amplitude of this movement of the brake and prevents the armature
from touching the iron rod.
Instead of a pivotted brake and attached armature as above described, the iron
armature may be pivotted and bear at its extremity an attachment embracing the
carbon carrier and acting as a brake.
This lamp comprises three circuits, videlicet:-First, the principle circuit or that of
the voltaic arc, Second, the shunt circuit of the solenoid C, and Third, that of the
coils B. B' which magnetises the iron carrier. The last mentioned circuit may be
traversed by an intermittent or by an alternating current, in the latter case the
armature is polarised. The said circuit is closed only when the attraction of the
solenoid C, is sufficient to draw up the iron core D, and cause contact to be made
between the points G and O.
The apparatus acts in the following manner :-) When an Electric Current traverses
the system, the carbons being separated, the solenoid C, is excited and raises the core D
so that contact is made between the carbon points, the force of the solenoid then
diminishing considerably, the core descends, the points are separated and the are is
produced.
The consumption of the carbons lengthening the arc, its electrical resistance
augments, and thus causes a more powerful current to pass in the coils of the shunt
solenoid C, the iron core D then rises until the contact-piece G touches the contact-
piece O.
The circuit of the coils B B is then closed, the intermittent or alternating
current traverses them and the iron carbon carrier A, being magnetized by the said
current, an intermittent or alternating polarity manifests itself in that portion of the said
carbon carrier which lies between the two coils and opposite to the armature K carried
by the brake I. Consequently assuming the current to be intermittent, the armature K is
attracted each time that the current passes and the attraction overpowering the tension
of the spring L, the brake I quits the carbon-carrier, leaving it free to fall, and at
each interruption of the current, the brake is again pressed by the spring L, against
the said carrier, thus stopping its downward movement. As the interruptions of the
current follow each other with considerable rapidity a vibrating movement of the
brake is produced, which allows the upper carbon carrier to descend very slowly until
the arc has reassumed its normal length. The current in the solenoid C is then
diminished so that the iron core D descends, and the contact between G and O is
broken. The intermittent current then ceases to pass in the coils B B and the
vibrations of the brake and the downward movement of the upper carbon-carrier is
arrested. These actions are repeated each time that the arc becomes two long and in
this way the upper carbon descends towards the lower carbon in proportion as the
points are consumed by the action of the current.
The lamp may be constructed with its parts arranged as hereinbefore described and
illustrated in figures 1 and 2 but it is preferred in practice to employ separate coils
for the "striking" of the arc and for the regulation of its length.
Figure 3 is a diagram showing the relative connections of the lamp as preferred
for practical use.

page_text: According to this arrangement the brake arm I is placed vertically and the iron
carbon carrier A and the rod E supporting the lower electrode are connected by a
cord passing over a pulley P in such a manner that the lower carbon rises in
proportion as the upper carbon descends. The lower or negative carbon is attached
to an iron disc X supported by a cylinder V which slides within the tubular or hollow
cone of an electro inagnet Y. To the lower extremity of the cylinder V is fastened
a screw threaded rod S working in a milled nutt. A spring (see dotted lines at Y')
tends to force the cylinder V upwards. An iron disc u forms the pole piece of the
magnet which is insulated from its support by two insulating washers i¹. The
distance between the discs and is regulated by means of the nut -C is a solenoid
with a fine wire coil placed in a shunt circuit. Within the said coil is suspended the
iron core D supported by a spring H. The lower end of this core is provided with a
rod F carrying a contact piece capable of making contact with a screw O arranged
underneath the rod F. On the passage of the current the magnet Y which is placed
in the main circuit attracts its armature (r) and thus " strikes the arc. As the
resistance of the arc increases the force of the shunt coil C draws downward the core D
until contact is made between the contact piece on F and the screw 0. The inter-
mittent or alternating current then passes in the coils B B' so that the brake vibrates
and the upper carbon carrier descends slowly as hereinbefore described.
Figure illustrates the lamp as constructed in practice the working parts being
marked with the same letters of reference as in the preceding figures. In this
arrangement the lower carbon holder is supported by rods E, E' connected by plates J..J¹
and suspended by a cord passing over pulleys P attached to a tube or support T.
This cord passing under a small pulley P¹ on the upper extremity of the upper carbon
carrier A causes the parallelogram formed by the rods E E' and the plates J and J¹
to ascend in proportion as the upper carbon carrier descends.
Tubes IL fastened by means of nuts to the insulating base act as guides for
the rods E and E¹.
Y is an electro magnet constructed as herein before described with reference to
figure 3 and serving to strike the arc in the first instance and to effect the relighting
in case of accidental extinction.
L is a spring pressing the brake I against the rod A being regulated by means of a
screw M (figures 34 and 5.
The fine wire regulating coil is placed upon the central portion of a supporting
tubo T fastened by nuts to the base 0. In this tube the iron cylinder D is suspended
by means of the spring H shewn in dotted lines in figure 4.
Openings are made in the sides of the tube T as shewn in the drawing in order to
expose the contact screw 0 and the rod F and thus facilitate their regulation or
adjustment. The brake I illustrated in side elevation in figure 5 and in horizontal
section in figure 6 bears two lugs or projections through which pass screws & s sustain-
ing the armature K. A collar N is fixed on the tube T in which the upper carbon
carrier A is free to move vertically and the brake I is pivotted on a pin P carried by
an arm on the said collar. The brake is provided with an arin 1 attached to the
spring L which tends to press the brake against the carbon carrier A.
It will be remarked that an opening is made in the tube T' opposite the brake in
order to expose the carrier rod A and allow the brake to act thereon but the armature K
is prevented from touching the iron rod A by the interposition of the tubo T¹ as
indicated by the horizontal section figure 6. The amplitude of the vibrations of the
brake is enabled to be regulated by means of the screws s herein before referred to.
If the arm I be made of iron and the block K of non magnetic material the
position of the spring L must be inverted and the tube T' perforated on the side
opposite to that indicated in the figure in order to allow the block K to press upon
the rod.
In the foregoing description the alternating or intermittent current is maintained
without any reference to its source I must explain that the said current may be
altogether auxiliary or independent and proceeds from a different generator of electricity
from that which produces the lighting current of the arc.
It is however more

page_text: convenient to employ coils of high resistance connected as a shunt around the are with
an interrupter or reverser placed in the circuit. An alternating current is not so
convenient as an intermittent current as the inversions cannot easily be produced
without the aid of a rotative apparatus. On the other hand the intermittent current
may be produced by extremely simple means. For example such a current may be
obtained (1) by placing in the circuit an electro-magnetic interruptor on the principle
of that of an induction coil or electric boll or (2) by a differential winding of the
regulating solenoid C or (3) by the employment of the brake itself as an
nterruptor.
The first mentioned method requires no explanation. The second will be readily
understood by reference to the diagram Figure 7. In this figure the circuit of the
coils BB is indicated by a full line that of the regulating coil by a dotted line. The
solenoid is wound differentially that is with two coils in opposite directions. One of
these coils (see dotted lines) is placed directly in a shunt around the arc. The second
forms part of the circuit of the coils B B. This arrangement acts as follows:-
Supposing that the consumption of the carbon points has caused the resistance of the
are to augment until it exceeds the pre arranged or normal limit the increasing force
of the derived circuit in the regulating solenoid draws downwards the coro D until
contact is established between the rod F and the screw 0. Thereupon the current
traverses the coils B B₁ the armature of the brake is attracted and the brake quits
the rod but at the same instant the solenoid C loses the greater part of its force since
the current which traverses the coils B B passes also in the second helix (see full
lines) of . The core is consequently drawn up the contact at F O is broken and the
brake again pressed against the rod. The rupture of the contact however reestablishes
the force of the solenoid C which by drawing down its core, again makes contact
at FO. The same actions are repeated with great rapidity until the resultant
vibrations of the brako have caused the are to resume its normal length.
The third method indicated in figure 8 consists simply in insulating the brake from
its support and the armature from the brake. As the current traverses the point of
contact between the brake and the carbon carrier it follows that when the arniature is
attracted towards the carrier the brake leaving the latter breaks the Contact, the brake
then resumes its original position the contact is again established the armature
attracted and the circuit broken. In this manner a rapid vibratory movement is
produced.
With this system the coils B B' may be placed permanently in circuit the move-
ment of the brake being prevented mechanically by the pressure of a projection on
the armature L (Figure 11) of a shunt magnet C which tends to draw downwards
the armature L² and release the brake.
A fourth method derived from the two preceding may also be mentioned. The
diagram figure 9 illustrates this method in which the brake I is insulated as before
but the contact between it and the Carbon carrier A is placed in the circuit of the
regulating solenoid C. A resistance R is connected with the brake and the carrier
respectively. On contact being made by the action of the solenoid C the armature of
the brake is attracted and the contact is broken between the brake and the Carbon
Carrier. The resistance R being thus thrown into the circuit of the solenoid C the
force of the latter is diminished so that the core rises and breaks the contact thereby
bringing the brake into action. The current then traverses the solenoid in its full
strength and the contact is again made. These actions continue until the normal arc
is reestablished.
The resistance R may be dispensed with and the movement of the brake allowed to
completely interrupt the circuit of the regulating solenoid. Or the resistance may be
wound upon the same bobbin as the coils of the said solenoid. It will be understood
that although the regulating solenoids and coils have been described as placed in the
shunt circuit they may be composed of thick wires placed in the main circuit or they
may be wound differentially.
It is not essential to the Invention that the carbon carrier A should be of iron as it
may be composed of any nonmagnetic metal but in this case the brake is of iron and

page_text: is acted upon by an ordinary electromagnet. An arrangement of this description is
indicated in figure 10.
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 is :-
First In an arc lamp, producing a slow feed motion of the carbons by means of
a vibratory action set up between an iron carbon carrier (surrounded by two coils of wire
traversed by an alternating or intermittent current the said coils being wound in oppo-
site directions in order to produce a magnetic pole in the said carrier between the two
coils) and an armature fixed to a brake or carrying an attachment embracing the
carbon carrier and acting as a brake which brake (or attachment fulfilling the office of
a brake) is normally pressed against the carbon carrier by a spring so as to prevent
the descent of the carbon carrier so long as the aforementioned alternating or inter-
mittent current does not pass in the said coils substantially as hereinbefore described
and illustrated in the accompanying drawings.
Second An electric are lamp regulated by the vibrations of a brake provided with
an armature or of an armature carrying a brake attachment the said vibrations being
produced by the magnetization of the iron carbon carrier by an intermittent current
the intermittency of the said current being produced by any suitable mechanism or
electro mechanical means exterior to the lamp itself or by a vibratory motion imparted
to the regulating contacts of the lamp or by the vibration of the brake against the
carrier substantially as and for the purpose herein before described.
Third :—Regulating the feed notion of an electric lamp by means of a vibrating
brake constructed and arranged as hereinbefore set forth the vibratory movement of
the said brake being controlled either by a regulating solenoid provided with a coils or
coils either in a shunt or in the main circuit or wound differentially and serving to
open and close the electric circuit of the coils acting on the brake or by mechanical
means arresting the brake or allowing the brake to vibrate as required and controlling
the descent of the carbon carrier according to the changes in the resistance of the arc
substantially as herein before described.
Fourth Producing the regulating action in an electric arc lamp by means of an
alternating or intermittent current produced by any of the means above mentioned
sent into two coils surrounding the iron carbon carrying rod so as to produce a
vibrating movement of the brake to which is attached or which is attached to an
armature placed opposite that part of the said rod which has between the two coils but
which armature is prevented from touching the aforementioned rod by a screw
limiting the movement of the brake or by a tube of copper or other non-magnetic
metal encasing the rod or by any other suitable mechanical means as illustrated and
described.
Fifth A lamp regulated by a brake either of nonmagnetic materials provided
with an armature or attachment to a movable armature as above described and acted
upon by the magnetization of the iron carbon carrier, or made of iron and bearing
upon a nonmagnetic carrier the said iron brake being placed within the influence of an
ordinary electro-magnet the magnetization of the carrier or the excitation of the
magnet being produced by an intermittent or alternating current controlled and
produced as hereinbefore set forth substantially as and for the purpose described.
Sixth-The several combinations and arrangements of parts constituting an
improved arc electric lamp substantially as herein before described with reference to
the accompanying drawings.
.