Improvements in Arc Electric Lamps.
Year: 1893

page_text: Date of Application, 19th Apr.,
1893
Complete Specification Left, 12th Jan., 1894-Accepted, 17th Feb., 1894
Improvements in Arc Electric Lamps.
I, ELIE VICTOR BUCHET, of 33 Avenue de Montsouris, Paris, France, Electrical
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to a construction of electric lamp wherein an electromagnet,
wound with fine wire in shunt, determines the action of the mechanism for regulating
the distance of the carbons. As the action of this magnet depends only on the
difference of potential at the terminals of its coil, it is not affected by the electrical
condition of the circuit in which the lamp is included, and therefore the lamp acts
equally well whether there be a less or greater current, whether there be a less or
greater number of lamps in the circuit, and whether the current be continuous or
alternating.
Fig. 1 of the accompanying drawings is a diagram illustrating one arrangement
of the regulating mechanism and connections, Fig. 2 is a side view of the lamp
having this mechanism, Fig. 3 is a plan on the line X X of Fig. 2, and Fig. 4 is a
section on the line Y Y of Fig. 3.
C is the electro magnet having a coil of fine wire in shunt, D is its armature
subject to a spring d or a weight d' acting on its insulated extension D' which is
connected by wire E to the + terminal of the lamp A and which makes contact
with e¹ or eaccording as the magnet C is less or more excited. The contacts e¹ e²
are connected respectively to the coils of two magnets F1 F2 which are provided with
spring armatures f¹ƒ2 arranged to make and break contacts and consequently to
oscillate when their respective magnets are in circuit. These armatures act as
pawls upon escapement wheels G1 G2 the one turning their axis in the one direction,
the other turning it in the opposite direction. On this axis is a worm gearing with
a worm wheel G on the axis H of a barrel H₁ from which the two carbons are
suspended. The current entering at the + terminal A passes through a suitable
resistance B to the metal work or mass of the lamp, thence through the carbons to
the terminal, a portion of the current passing through the coil of C and through
the coils of F1 and F2 when these are brought into circuit by means of the
contacts e¹ e². When the carbons are in contact, the magnet C receives very little
current, consequently there is contact at e¹, the magnet F¹ is excited and its
armatureoscillates moving G¹ and H¹ so as to separate the carbons, striking the
arc.
When, owing to consumption of the carbons, the resistance of the arc
increases, the magnet C is sufficiently excited to attract its armature, making a
contact at e, so that the magnet F is excited and its armature f2 is caused to
oscillate, moving G² and H¹ so as to bring the carbons nearer to one another.
Thus, according as the magnet C is excited or not, owing to the greater or less
resistance of the arc, the electromagnets F F¹, determine the approach or the
separation of the carbons.
According to a modification, shewn diagrammatically in Fig. 5, the oscillating
armature of the magnet F¹ serves to separate the carbons whilst the armature of F²,
when it is attracted, merely disengages a pawl, so that the carbons are allowed to
approach each other, being so weighted that they tend to do so when free. When
the carbons are so weighted that they tend to separate when free, the arrangement
of Fig. 5 is inverted as shewn diagrammatically in Fig. 6.

page_text: In the diagrams Figs. 1, 5 and 6 the directions of the currents are indicated by
arrows.
20
די
1000
ABEL & IMRAY,
Agents for the Applicant.
Improvements in Arc Electric Lamps.
I, ELIE VICTOR BUCHET, of 33 Avenue de Montsouris, Paris, 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 :-
My invention relates to arc electric lamps in which the mechanism which
determines the distance of the carbons is controlled by an electro-magnet wound
with fine wire in shunt, and it comprises certain electrical and mechanical devices
for ensuring the proper action of this mechanism.
In my lamps the variations of the attractive force of the magnet on its armature
constitute the prime but indirect cause of the striking of the arc and its regulation ;
these variations act on the armature of an electro magnet or on the moveable core
of a solenoid, and this armature acts as a relay so as to determine at the required
moments the closing of necessary circuits causing or preventing the approach of the
carbons. As the coil is in shunt between the terminals, the variations of its
attractive force depend solely on the variations of difference of potential at the
terminals, without in any way depending on the intensity of the current through
the carbons. Hence the distance of the carbons is so regulated that the difference
of potential at the terminals is constant, whatever be the intensity of the current
through the carbons. The lamp may therefore be said to have constant electro
motive force with variable intensity. The advantages which result from this
property are that, on the one hand, the lamp works as well with a current say of
two ampères as with one of ten ampères, and that, on the other hand, owing to the
constant difference of potential at the terminals, two or more lamps can be arranged
in series on a circuit of high electro motive force. Moreover, the lamp serves either
for continuous or for alternating currents.
Usually, in my lamps, the coil which acts as relay, controls two distinct electro
magnets, the one producing or preventing the approach of the carbons, the other
producing or preventing their separation. The circuits of these magnets must
therefore vary according as the carbons are in equilibrium passively obeying the
regulating mechanism, or as they tend on the contrary to approach or to separate.
The drawings accompanying my Provisional Specification shew the arrangements
which I adopt to meet the above conditions. In all cases, the carbon holders are
suspended by cords or their equivalents which are coiled in opposite directions on a
drum, to which they are fastened in order to prevent slip.
Case I. Fig. 1 shews diagrammatically the arrangement adopted when the
carbons are in equilibrio and the approach or separation of the carbons has to be
positively produced; that is to say, the drum from which the carbons are suspended
must be turned by the regulating mechanism. Fig. 2 is an elevation of a lamp
exemplifying these conditions, Fig. 3 is a plan on the line X X of Fig. 2, and Fig. 4
is a vertical section on the line Y Y of Fig. 3. The oscillating armatures of the
two regulating magnets are furnished with pawls gearing with ratchet wheels on a
spindle which works the drum by worm gear, the two armatures turning it in
opposite directions. As the movement is communicated through a worm, the
carbon holders are always ready to obey without being able to impart movement.
As shewn in Fig. 4, the current entering at the terminal A traverses a resistance B,
indicated diagrammatically, passes, either directly or through the metal of the lamp,

page_text: to the positive carbon, then through the negative carbon to the other terminal.
The resistance B serves solely to cause a sufficient portion of the current to act on
the regulating magnets with certainty. C is the regulating electro-magnet or relay
having its coil of fine wire in shunt between the terminals. It has an oscillating
armature D which a spring d, Fig. 1, or a weight d', Fig. 4, draws away from the
magnet, and which carries an insulated arm D connected by a flexible wire with
the entering terminal and furnished with two contacts facing the insulated contacts
leading to the regulating electro magnets F1 F2 which cause respectively the
separation and approach of the carbons. According as the attraction of the
magnet C is equal to or greater or less than the force of the spring d or weight d',
the armature takes a medium or an upper or lower position. In the medium
position, the circuits of F1 F2 are both opened; in the upper position the circuit
of F2 is closed causing approach of the carbons; in the lower position the circuit
of F¹ is closed causing separation of the carbons. The coil of F¹ is of large wire, in
shunt between the entering terminal and a resistance in connection with the positive
carbon so that the current which excites F¹ passes also through the carbons. This
circuit, which is normally open, causes separation of the carbons when it is closed
by the action of the magnet C, its armature f¹ being caused to oscillate turning the
ratchet wheel G, which by means of the worm G moves the spindle H carrying the
drum H' in the direction to separate the carbons. The coil of F2 is of fine wire in
shunt between the terminals of the lamp. When its circuit, which is usually open,
is closed by the action of C, its armature f' is made to oscillate turning the ratchet
wheel G' and the drum H' so as to cause approach of the carbons.
The armature of F' or F2, when the circuit is closed by C at e' or e² is caused to
oscillate in the following manner:-The wire from the coil F¹ is led to a contact f;
the armature has a contacts in connection with the positive carbon, and it is
subject to a spring f which keeps f and f³ in contact so that usually the circuit of the
coil is closed at these contacts. But when the armature is attracted the contact
off with fis broken and the circuit is opened, the spring f' draws back the
armature, closing the contact again, and the alternation is repeated causing the
armature to oscillate.
If the carbons be separated when the lamp is put in circuit, then current will
traverse the coil of C which will attract its armature closing the circuit of F
ate and then the armature f' will cause the approach of the carbons causing the are
to be struck. But now the resistance of the inain circuit being lessened, C will
receive less current, its armature D will be drawn back by the spring or weight
opening the circuit of F2, and closing the circuit of F at e¹ and by the action of
the armature f¹ the carbons will be separated. When the distance has become
normal, the resistance in the main circuit is such that the current in C is just
sufficient to maintain its armature in the medium position the circuits of F' and F
remaining open. As owing to consumption of the carbons, the resistance in the
main circuit increases, the circuit of F is closed causing approach of the carbons
until their distance becomes normal.
Case II. I shall now explain with reference to Fig. 5 the modifications made to
suit the case where the carbons tend to approach each other owing to excess of
weight of the upper holder. In order to produce approach of the carbons it is
only necessary for the armature f to withdraw a detent so as to allow rotation
of the drum by which the carbons are suspended. For this purpose, the coil of F³ is
of large wire in shunt circuit never opened between the entering terminal and the
positive carbon. When there is no current, the detent is withdrawn by spring ƒ³
and the carbons approach till they meet. When the lamp is put in circuit, the
coil F, being traversed by much current, attracts its armature and the detent f
engages the ratchet wheel G² preventing subsequent approach of the carbons. But,
as there is very little difference of potential at the terminals, very little current
traverses the coil of C, its armature therefore makes contact at e¹ and the
oscillating armature f¹ separates the carbons until their distance is normal and
thereupon receives such current that its armature D is attracted opening the

page_text: circuit of F and causing the action of f¹ to cease. As the distance of the
carbons is increased by their consumption the coil F2 receives less current, its
armature obeys its spring f withdrawing the detent fallowing the carbons to
approach until they obtain their normal distance, whereupon the detent again
engages G2 preventing their farther approach.
Case III. When the carbons tend to separate, owing to excess of the
weight of the lower holder, the magnet F has simply to stop the separating
movement, the oscillating armature of the magnet F2 causing approach. As shewn
in Fig. 6; the coils of both F1 and 2 are of fine wire in shunt between the
terminals, the resistance B being dispensed with. The contact el is directly
connected to the entering terminal A, it is kept separate from E', the end of
the coil wire, by the armature D when held by its spring d, the circuit of F¹
being then open; but when the armature D begins to move in obedience to the
attraction of C, the spring contact e' meets E and closes the circuit of F¹. The
coil of F2 is arranged as in Case I, as may be seen in comparing the diagrams
Figs. 1 and 6. The operation in this case is as follows. In repose, the armature fi
is urged by its spring f raising the detent f so that the carbons separate to the
maximum extent, but as soon as the lamp is put in circuit the magnet C attracts
its armature the circuit of F¹ is closed at e¹ Ei, the armature f¹ is attracted and
lets the detent f* engage the ratchet wheel so as to prevent subsequent separation
of the carbons. At the same time D continuing to move in obedience to the
attraction closes at e² the circuit of F2, the armature of which oscillates, causing the
carbons to approach and meet. As the resistance is now very small, the difference
of potential at the terminals is very little, so that scarcely any current traverses
the coil C; its armature D is drawn back by its spring, opening the circuits of F¹
and F. The armature f' then withdraws the detent f and the carbons separate,
striking the arc. When the distance is normal, the resistance of the main circuit
is so far increased that C attracts its armature closing at e¹ the circuit of F³, so
that the detent again engages the ratchet wheel G' and prevents too great
separation of the carbons. The armature D is then in medium position, but, as the
distance of the carbons is increased by their consumption, the difference of
potential at the terminals increases, causing C to attract more strongly its armature
which then closes at the circuit of F; its armature then oscillates causing
approach of the carbons to their normal distance, whereupon D resumes its medium
position opening the circuit of F".
It is to be understood that the resistances of the several circuits, whether they
be coils of electro magnets or of solenoids which may be substituted for
magnets, have to be determined to suit the conditions of their respective actions.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that I
claim in respect of arc electric lamps in which the carbons are controlled by an
electromagnet or solenoid having a coil of fine wire in shunt between the terminals,
the following improvements; that is to say, what I claim is,
1. In the case of carbons in equilibrio, the combination of the electro magnet C,
acting as relay, with resistance B in the circuit of the carbons, with the two
contacts e e, the magnet F2 with fine wire coil for causing approach, and the
magnet F with large wire coil for causing separation of the carbons, both magnets
having oscillating armatures, and the electric connections, substantially as
illustrated by Figs. 1 to 4 inclusive and for the purpose set forth.
2. In the case of carbons tending to approach, the combination of the relay
electro magnet C with resistance B in the circuit of the carbons, the contact e', the
stop magnet F with coil of large wire, the separating magnet F¹ also with
coil of large wire and with oscillating armature, substantially as described with
reference to Fig. 5 and for the purpose set forth.
3. In the case of carbons tending to separate, the combination of the
magnet C, the contact e³, the circuit interrupter e', the stop magnet F¹ with coil of

page_text: fine wire, the magnet F' with coil of fine wire and oscillating armature for causing
approach of the carbons, and the electric connections, substantially as described
with reference to Fig. 6 and for the purpose set forth.
4. An arc electric lamp constructed and arranged substantially as described with
reference to Figs. 2 and 4.
D
2004
ABEL & IMRAY,
Agents for the Applicant.