Improvements in Regulating Apparatus for Electric Arc Lamps.
Year: 1884

page_text: Improvements in Regulating Apparatus for Electric Arc Lamps.
I, GEORGE EDWARD VAUGHAN, of 57, Chancery Lane, in the county of
Middlesex, Patent Agent, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN REGULATING APPARATUS FOR ELECTRIC ARC LAMPS," being a
communication to me from abroad by The Austrian Small Arms Manufacturing
Company, of Steyr, in the Empire of Austria, to be as follows:-
The lamp which forms the subject of this invention belongs to that class of
electric arc lamps known as "shunt lamps and may be burned by itself or with
several others, at the same time, in the same electric circuit.
The principal features of this invention are as follows:-
1. One or both of the carbons, between the points of which the light arc is
formed, is or are guided and held between guide rollers. The approaching
movement, or the successive push, necessary for keeping the light arc constant, is
effected by a shunt mechanism which is put in action by an electro-magnet or
solenoid disposed for automatic "current weakening" or "demagnetisation
placed in the shunt circuit as soon as the light are has reached a certain length,
and the current circulating in the shunt circuit has increased to the required
intensity.
and
The leading object of this invention is to remove sensitive mechanical details
such as are required where the approaching movement of the carbons is effected by
gravitation or by a spring.
2. The lamp is provided with an automatic shunt arrangement, by means of
which a second path (besides that over the carbons) is supplied for the principal
current in case it is interrupted from any cause, but especially for lighting the
lamp when the carbons do not touch. In this second path the current passes
through a powerful electro-magnet and resistance coil inserted behind it which
re-establishes approximately the light arc.
The carbon holder is set free on the
magnet attracting the armature, so that it glides downwards without the action of
the shunt arrangement, by means of its weight, until the upper carbon carried by
it touches the lower one.

page_text: In this manner no interruption is possible, and the lighting takes place at once
even if the carbon points should be at some distance from each other.
3. Finally, an automatic safety apparatus is provided in this lamp, which
prevents an abnormal length of the arc, in case, owing to some irregularity in the
shunt mechanism, the latter should not push together the carbon points.
This safety apparatus consists of a lever, which forms the armature of the
second pole of the shunt magnet. If this armature, which is restrained by a spring
of sufficient strength, is attracted, (which happens when the arc has sensibly
exceeded the normal length), a contact is established which opens up to the current
the path described under condition 2. and thus puts in action the shunt arrangement
also explained under condition 2.
The annexed drawing gives a perfect view of the lamp, and, as the casing,
covering the apparatus is removed, permits of all the principal parts being seen.
All the mechanical details as well as the magnets, of this lamp are arranged
partly on the round base plate Q., and partly on the upper plate Q'. These two
plates are joined to each other by two connecting pillars, which, however, are not
shown in this drawing.
In the centre of the plates, and insulated from them, is the upper carbon holder
and rod H. carrying the carbon G. This carbon rod H. is held between the guide
roller D. the spring contact roller d. the friction roller F. and the brake roller r.
pressed against it by the spring X.
On the upper plate the roller angle piece Cx is fixed and is also insulated from
the plate. This roller angle piece carries the guide roller D. the spring of the
contact roller d. the shunt lever E. and the spring q. which latter pulls the
lever F¹.
There are also fixed to, and insulated from, the upper plate, the two current
rods B. and N., the shunt contact bolt R., and the insulating piece 1.
The current rods B. and N. are held together at their upper ends by means of an
insulating piece 1¹ which is fixed to them by the female screws which form, at the
same time, the polo binding screws A. and O.
An eye 2. is fixed to the centre of the crosspiece 1¹, by which the lamp is
suspended.
The following parts are arranged, all insulated, on the base plate Q; that is
to say.
The magnet pillars I. I., of which one only is shown here, carrying the double
magnet M. M., of which only one is shown. The magnets M. M. are connected
with each other by the back armature L¹. The carbon holder L., carried in the
back armature L₁ and in the base plate Q. (insulated from it) moves between the
magnets M. M.
At the upper end of the carbon rod L., a crosspiece of iron or armature P. is
fixed, which crosspiece is placed before the two poles of the double magnet M. M.
and consequently forms its armature.
At the lower end of the rod L. the carbon holder K. is fixed, carrying the
negative carbon J. The rod L. is, at its upper end, provided with an insulator a
which prevents metallic contact with the lever E. In the movable carbon rod, and
at the back armature L³, fixed to the pillar I., two small brackets 3. and 4. arc
secured, between which the spring U. is hung, which spring pulls the movable rod
upwards, and consequently against the lever E, and presses the latter against the
contact bolt R.
The electro magnet N¹, which is covered with two layers of fine wire, belongs to
the shunt mechanism. The inner layer (represented by a double line a¹) is of
copper wire, the outer (represented by a thick line e¹) of German silver wire. Each
of these layers offers a resistance of about 500 ohms, together 1000 ohms. The
electro-magnet N¹ is secured to angle bracket T¹ by a female screw, and the said
bracket is screwed down to the base plate Q.
The regulating lever R¹ (forming the armature of the magnet N¹ at pole 5. ;) to
which is fixed the pawl u.; the counter-pawl u¹; the cog-wheels v. and v', gearing

page_text: into each other; the ratchet-wheel Z.; the spring w. (the tension of which may be
varied by the screw h. through the nut t. which is insulated in the angle
bracket T¹), and the contact lever B₁ all form part of the shunt mechanism.
The axles s. and s' rest in insulated blocks fixed to the bottom plate which blocks
are not shown in the drawing.
The regulating lever R¹ turns freely on the axle 8. The cog-wheel v. and ratchet
wheel Z. are fixed on the said axle.
The cog-wheel v¹ and the friction roller F. are secured to axle 8' and are actuated
by the cog wheel v which is moved with the wheel Z. The counter pawl u', is
mounted on the axle. 8¹ in such a manner that it may revolve independently
thereof.
On the bottom plate Q. there are also the electro magnet S. of thick wire and a
bracket supporting the axle i. of the lever T. T.
On the lever T. there is a roller r. upon which bears the carbon rod H. The
roller r. is called the brake roller, because, on the one hand, it is pressed against
the carbon rod H. by the spring X. acting upon the lever T. consequently holding
the carbon rod, and, on the other, when the magnet begins to act and attracts the
lever T., which forms its armature, this roller is removed from the rod H. and sets
it free, so that, in consequence of its weight it glides down between the guide
rollers.
The spring X. is attached to screw y. which is secured, and insulated, in the
plate Q. and may be set at any tension by means of the nut, according to the force
of the magnet S.
The action of lamps constructed as hereinbefore described is as follows:-
1. The carbons are in contact at the moment of lighting. The current, taking
its course from the positive pole, enters the lamp through the binding screw A.,
passes along in the direction of the line e³ through the rod B. to the roller angle
piece C* which is electrically joined to rod B. The roller angle piece Cx is in
inetallic connection with the guide roller D., with the contact roller d., secured by
a spring, the shunt lever E. and the safety lever F'.
In this case the current passes from the angle piece C* to the rollers D. and d.
carbon rod H. which is held between these two rollers, and carbon G; from
carbon G. to carbon J., to carbon holder K. rod L., back armature L' and from
there through the wire coils of the electro-magnet M. M. and the rod N. to the
binding screw of pole O., and off.
At the moment that the current passes the wire coils of the electro magnet M. M.
its poles (only one of which is shown) attract both the armature P. and the shunt
lever E., the ends of which are supported and insulated.
In attracting the armature P. the magnet M. M. must overcome the resistance of
the spring U. which pulls the carbon rod L. upwards against the lever E. By the
downward movement, the carbon points G, and J. are drawn apart, and the arc is
formed, whilst, at the same moment, the lever E, which is pulled by the spring m.
against the contact bolt R., is attracted by the magnet M. M. towards it.
2. Supposing the carbons are not in contact at the moment the current is
turned on.
In this case the current takes its course from the roller angle Cx through the
shunt lever E., as the shorter course, in consequence of the circuit being broken
through the carbons being apart.
As the electro magnet M. M. is now out of action, the shunt lever E. remains in
connection with the contact bolt R. the current, consequently, takes its course
from E., through R. and flows in the direction marked by dashes and dots it, through
the coils of the thick wire electro-magnet S. passes over at the point b. to the German
silver spirals W., fixed to the insulators 1. 1', and possessing a resistance approxi-
inating that of the arc, whence it reaches the rod N. through the connecting wire k.,
and through the rod to the negative binding screw O. where it leaves the lamp.
At the moment that the current passes through the coils of the electro magnet S.;
the latter attracts the long arm of the brake lever T. which forms its armature,

page_text: towards its pole, a movement which causes the brake roller r. to recede. Through
this action the rod H. is set free, and descends by reason of its weight, but is guided
between the rollers D., d., and F. until the carbon G. fixed in it touches the lower
carbon J.
At this moment, however, the current resumes the course explained under
condition 1. which offers less resistance. The magnetic force, consequently, of the
electro-magnet S. ceases, the spring X. pulls the lever T. away from its pole,
presses the brake roller r. again against the rod H., the latter thereby against the
friction roller F., and the rod H. is again held firmly.
The current now resumes its course through the magnet M. M. which attracts its
armature P. and the shunt lever E., by which the arc is restored and the path
through the bolt R. interrupted.
The current, therefore, without dividing itself, must take its course again through
the arc.
Besides the two current courses described under conditions 1. and 2. there exist
two others in the shunt, that is to say:-
(a.) From the positive pole, the current passes through the rod H. the regulating
lever R¹ (which forms the armature of the shunt magnet N¹,) through the contact n.
to the perfectly insulated movable contact lever B₁, on which one end of the copper
wire, forming the inner layer of the magnet N¹, is fixed, and reaches, in the direction
of the double line a¹, through the coils of this wire, the negative pole.
(b.) From the roller angle piece C* the current passes, in the direction of the
line e through the German silver wire coils of the magnet N¹ and the point p. and
continues from there in the direction described under (a). In this latter course,
however, the current having to overcome a double resistance, will, therefore, only
take it when the contact existing at n. is interrupted.
The explanations which follow will elucidate the principle of the arrangement
lastly referred to.
The process of regulation is as follows:-
If through the consumption of the carbons the resistance in the arc increases
sensibly, the strength of the current in the coils of the shunt magnet N¹ is
augmented to such an extent that its magnetism is sufficient to overcome the
spring w. and to attract the lever R¹. By this the shunt mechanism described
above is put in motion and the carbons are pushed on.
In regulating the lamp, it is observed that the contact n. is maintained only long
enough for the cog-wheel Z. to move one tooth forward. The lever B is then
arrested by the pin l., the contact at n. interrupted, and the current now takes the
course herein before described under condition 2. The magnetism generated through
the German silver coils in the spool N¹, however, is not able to attract the lever R¹
any more, the spring w. being too powerful. The contact n. is again restored,
and, in case the arc is not yet normal, a further pushing down of the carbon
holder takes place, until the magnetic action of N¹ and the spring w. balance each
other.
-
The automatic safety arrangement mentioned under condition 3., is operated by
the second pole 6. of the shunt magnet, and acts in the following manner.
The lever F¹ is of iron, and forms the armature of the pole 6. This lever is kept
away from pole 6. by a spring q. which spring is put at the required tension. The
lever F¹ is well connected electrically with the positive pole.
Over the pole 6. on the angle bracket T¹ a small contact bolt c. is fixed, and
insulated, which bolt is connected by the wire g. at the point s¹¹ with the coils of
the magnet S. As long as the arc is of normal length, pole 6. does not act upon
the lever F¹ as the magnetism is too weak to overcome the counter pull of the
spring q. But as soon as the arc is no longer normal, through any irregularity in
the shunt mechanism, its resistance increases, consequently to the same degree the
strength of current is augmented in the magnet N¹. As soon as this current
strength reaches a certain height, previously determined, so that the power of the

page_text: magnet exceeds that of the spring q. the lever F¹ is attracted towards pole 6. which
causes a contact of this lever with the bolt c.
As, the lever F¹ is now electrically connected with the positive pole, the course
described under condition 2. is opened to the current, and as it offers less resistance,
than that through the arc, which is, besides, too long, the current will enter it at
once, namely, in the direction of the line from the lever F¹ to the contact bolt c.
through the coils of the magnet S. over pole 6. spiral W. rod N., to the negative
binding screw O. and off.
The principal advantage of the above described safety arrangement is this, that
the shunt is effected at a relatively small arc, little exceeding the normal length.
With an arc, on the contrary, which does not yet disturb the remaining arcs
burning in the same circuit, the automatic interruption of the are would have to be
waited for in order to effect the shunt, and frequently a very long arc which
would have a great effect upon the whole circuit, would precede this action.
Should now the shunt mechanism from any cause refuse to act, or the carbons
be burned completely down, the resistance W., corresponding to the arc, enters
automatically, (as shown in the drawing,) and consequently the action of the other
lamps is not disturbed.
For the sake of simplicity, and to show clearly the principle involved, an are
lamp construction is chosen for the subject of the accompanying drawing, in which
only one of the two carbons is moved by the shunt mechanism, the carbons are
placed vertically above each other, so that their axes fall in one straight line, and
the luminous point is below the mechanism as is usually the case with suspended
lamps. The principle by which the carbons are held and moved permits of their
working towards each other at all possible angles of inclination, even horizontally,
of moving, according to requirements, either both carbons or only one, towards
each other, and of employing currents of the same or alternating directions.
Further, all parts which now occupy their positions in consequence of their
gravity are kept in their places by springs or other means.
The sudden approaching movement of the carbons, likewise, takes place as
required by the shunt arrangement, under the pressure of a counterbalance weight
or spiral spring.
But the feeding of the carbons, when alight, however the parts may be arranged,
is effected solely by the shunt mechanism worked by the shunt electro-magnet or
solenoid disposed for automatic current weakening, or demagnetisation.
Thus solenoids may take the place of electro magnets in all cases where a more
uniform and more sensitive attraction is desired.

page_text: COMPLETE SPECIFICATION.
Improvements in Regulating Apparatus for Electric Arc Lamps.
I, GEORGE EDWARD VAUGHAN, of 57, Chancery Lane, in the county of Middlesex,
Patent Agent, do hereby declare the nature of the invention for "IMPROVEMENTS
IN REGULATING APPARATUS FOR ELECTRIC ARC LAMPS," being a communication to
me from abroad by The Austrian Small Arms Manufacturing Company, of Steyr,
in the Empire of Austria, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The lamp which forms the subject of this invention belongs to that class of
electric arc lamps known as "shunt lamps" and may be burned by itself or with
several others, at the same time, in the same electric circuit.
The principal features of this invention are as follows:-
1. One or both of the carbons, between the points of which the light are is
formed, is or are guided and held between guide rollers. The approaching move-
ment, or the successive push, necessary for keeping the light are constant, is effected
by a shunt mechanism which is put in action by an electro-magnet or solenoid
disposed for automatic "current weakening or demagnetisation and placed in
the shunt circuit as soon as the light are has reached a certain length, and the
current circulating in the shunt circuit has increased to the required intensity.
"
"
The leading object of this invention is to remove sensitive mechanical details
such as are required where the approaching movement of the carbons is solely
effected by gravitation or by a spring.
2. The lamp is provided with an automatic shunt arrangement, by means of
which a second path (besides that over the carbons) is supplied for the principal
current in case it is interrupted from any cause, but especially for lighting the lamp
when the carbons do not touch. In this second path the current passes through
a powerful electro magnet and resistance coil inserted in series with it, which
re-establishes, approximately, the light arc. The carbon holder is set free on the
magnet attracting the armature, so that it glides downwards, without the action of
the shunt arrangement, by means of its weight until the upper carbon carried by it
touches the lower one.
In this manner no interruption is possible, and the lighting takes place at once
even if the carbon points should be at some distance from each other.
3. Finally, an automatic safety apparatus is provided in this lamp, which
prevents an abnormal length of the arc, in case, owing to some irregularity in the
shunt mechanism, the latter should not push together the carbon points.
This safety apparatus consists of a lever, which forms the armature of the second
pole of the shunt magnet. If this armature, which is restrained by a spring of
sufficient strength, is attracted, (which happens when the are has sensibly exceeded
the normal length), a contact is established which opens up to the current the path
described under condition 2. and thus puts in action the shunt arrangement also
explained under condition 2.

page_text: Reference is hereinafter made to the letters on the drawing accompanying the
provisional specification filed with this application which drawing is a view of the
mechanism of a lamp constructed in accordance with this invention.
All the mechanical details as well as the magnets, of this lamp are arranged
partly on the round base plate Q., and partly on the upper plate Q¹. These two
plates are joined to each other by two connecting pillars, which, however, are not
shown in this drawing.
In the centre of the plates, and insulated from them, is the upper carbon
holder H. carrying the carbon G. This carbon holder H. is held between the guide
roller D. and the spring contact roller d. the friction roller F. and the brake roller r.
pressed against it by the spring X.
On the upper plate the roller angle piece C* is fixed and is also insulated from
the plate. This roller angle piece carries the guide roller D., the spring of the
contact roller d. the shunt. lever E., and the spring q. which latter pulls the lever F¹.
There are also fixed to, and insulated from, the upper plate, the two current
rods B. and N, the shunt contact bolt R., and the insulating piece 1.
The current rods B. and N. are held together at their upper ends by means of an
insulating piece 1' which is fixed to them by the female screws which form at the
same time the pole binding screws A. and O.
An eye 2. is fixed to the centre of the cross piece 11 by which the lamp is
suspended.
The following parts are arranged, all insulated, on the base plate Q., that
is to say;
The magnet pillars I. I., of which one only is shown here, carrying the double
magnet M. M., of which only one is shown. The magnets M. M. are connected with
each other by the back armature L¹. The carbon holder L. carried in the back
armature L' and in the base plate Q. (insulated from it) moves between the
magnets M M.
At the upper end of the carbon rod L. a crosspiece of iron or armature P. is fixed,
which crosspiece is placed before the two poles of the double magnet M. M. and
consequently forms its armature.
At the lower end of the rod L. the carbon holder K. is fixed, carrying the
negative carbon J. The rod L. is, at its upper end, provided with an insulator a.
which prevents metallic contact with the lever E. In the moveable carbon rod,
and at the back armature L' fixed to the pillar I., two small brackets 3. and 4. are
secured, between which the spring U. is hung which spring pulls the moveable rod
upwards and consequently against the lever E. and presses the latter against the
contact bolt R.
The electro magnet N' which is covered with two layers of fine wire, belongs to
the shunt mechanism. The inner layer (represented by a double line a¹) is of copper
wire, the outer (represented by a thick line e¹) of German silver wire. Each of
these layers offers a resistance of about 500 ohms, together 1,000 ohms.
electro-magnet N¹ is secured to angle bracket T¹ by a female screw, and the said
bracket is screwed down to the base plate Q.
The
The regulating lever R¹ (forming the armature of the magnet N¹ at pole 5 ;) to
which is fixed the pawl u. the counterpawl u' the cog-wheels v. vl gearing into each
other, the ratchet wheel Z., the spring w., the tension of which may be varied by
the screw h. through the nut t. which is insulated in the angle bracket T¹, and the
contact lever B' all form part of the shunt mechanism.
The axles s. 8¹ rest in insulated blocks fixed to the bottom plate which blocks are
not shown in the drawing.
The regulating lever R' turns freely on the axle s.
ratchet wheel Z. are fixed on the said axle.
The cog-wheel v. and
The cog-wheel v¹ and the friction roller F. are secured to axle s¹and are actuated
by the cog wheel v. which is moved with the wheel Z. The counter-pawl u¹ is

page_text: mounted on the axle 8 in such a manner that it may revolve independently
thereof.
On the bottom plate Q. there are also the electro-magnet S. of thick wire and
a bracket supporting the axle i of the lever T. T.
On the lever T. there is a roller r. bearing upon the carbon holder H. The
roller r. is called the brake roller, because, on the one hand, it is pressed against the
carbon holder H. by the spring X. acting upon the lever T., consequently holding
the carbon rod, and, on the other, when the magnet begins to act and attracts the
lever T. which forms its armature, this roller is removed from the rod H. and sets
it free, so that, in consequence of its weight it slides down between the guide
rollers.
The spring X. is attached to screw y. which is secured, and insulated, in the
plate and may be set at any tension by means of the nut, according to the force
of the magnet S.
The action of lamps constructed as hereinbefore described is as follows:-
1. The carbons are in contact at the moment of lighting. The current, taking
its course from the positive pole, enters the lamp through the binding screw A.
passes along in the direction of the line e2 through the rod B. to the roller angle
piece C which is electrically joined to rod B. The roller angle piece C* is in
metallic connection with the guide roller D. with the contact roller d. secured by a
spring, the sbunt lever E. and the safety lever F¹.
In this case the current passes from the angle piece Cx to the rollers D. and d.
carbon rod H. which is held between these two rollers, and carbon G.; from
carbon G to carbon J., to carbon holder K., rod L. back armature L¹, and from
there through the wire coils of the electro-magnet M. M. and the rod N to the
binding screw of the pole O., and off.
At the moment that the current passes the wire coils of the electro magnet M. M.
its poles (only one of which is shown) attract both the armature P. and the shunt
lever E. the ends of which are supported and insulated.
In attracting the armature P. the magnet M. M. must overcome the resistance of
the spring U., which pulls the carbon rod L. upwards against the lever E. By the
downward movement the carbon points G. and J. are drawn apart, and the arc is
formed, whilst at the same moment, the lever E. which is pulled by the spring m.
against the contact bolt R. is attracted by the magnet M. M. towards it.
2. Supposing the carbons are not in contact at the moment the current is
turned on.
In this case the current takes its course from the roller angle Cx through the
shunt lever E., as the shorter course in consequence of the circuit being broken
through the carbons being apart.
As the electro-magnet M. M. is now out of action, the shunt lever E. remains in
connection with the contact bolt R. the current, consequently, takes its course
from E. through R. and flows in the direction marked by dashes and dots i¹ through
the coils of the thick wire electro-magnet S., passes over at the point b. to the
German silver spirals W., fixed to the insulators 1. 11 and possessing a resistance
approximating that of the arc, whence it reaches the rod N. through the connecting
wire k. and through the rod to the negative binding screw O., where it leaves the
lamp.
At the moment that the current passes through the coils of the electro-magnet S.
the latter attracts the long arm of the brake lever T., which forms its armature,
towards its pole, a movement which causes the brake roller r. to recede. Through
this action the rod H. is set free, and descends by reason of its weight but is guided
between the rollers D. d. F. until the carbon G. fixed in it touches the lower
carbon J.
At this moment, however, the current resumes the course explained under
condition 1. which offers less resistance. The magnetic force, consequently, of the
electro-magnet S. ceases, the spring X. pulls the lever T. away from its pole, presses

page_text: the brake roller r. again against the rod H. the latter thereby against the friction
roller F., and the rod H. is again held firmly.
The current now resumes its course through the magnet M. M. which attracts its
armature P. and the shunt lever E. by which the arc is restored and the path
through the bolt R. interrupted. The current, therefore, without dividing itself,
must take its course again through the arc.
Besides the two current courses described under conditions 1. and 2. there exist
two others in the shunt, that is to say:
(a). From the positive pole, the current passes through the rod H., the regulating
lever R (which forms the armature of the shunt magnet N¹) through the
contact n. to the perfectly insulated moveable contact lever B¹ on which one end
of the copper wire forming the inner layer of the magnet N¹ is fixed, and reaches,
in the direction of the double line a¹ through the coils of this wire, the negative
pole.
(b.) From the roller angle piece Cx the current passes, in the direction of the
line e through the German silver wire coils of the magnet N' and the point p.,
and continues from there in the direction described under (a).
In this latter course, however, the current having to overcome a double
resistance, will, therefore, only take it when the contact existing at n. is
interrupted.
The explanations which follow will elucidate the principle of the arrangement
lastly referred to.
The process of regulation is as follows:-
If through the consumption of the carbons the resistance in the arc increases
sensibly the strength of the current in the coils of the shunt magnet N' is
augmented to such an extent that its magnetism is sufficient to overcome the
spring w. and to attract the lever R¹. By this the shunt mechanism described
above is put in motion and the carbons are pushed on.
In regulating the lamp it is observed that the contact n. is maintained only long
enough for the cog wheel Z. to move one tooth forward. The lever B¹ is then
arrested by the pin l., the contact at n. interrupted, and the current now takes the
course hereinbefore described under condition 2. The magnetism generated through
the German silver coils in the spool N¹ however, is not able to attract the lever R¹
any more, the spring w. being too powerful. The contact n. is again restored, and,
in case the arc is not yet normal, a further pushing down of the carbon holder
takes place, until the magnetic action of N' and the spring w. balance each
other.
The automatic safety arrangement mentioned under condition 3. is operated by
the second pole 6. of the shunt magnet, and acts in the following manner.
The lever F is of iron, and forms the armature of the pole 6. This lever is kept
away from pole 6. by a spring q. which spring is put at the required tension. The
lever F is well connected electrically with the positive pole.
Over the pole G. on the angle bracket T¹ a small contact bolt c.. is fixed, and
insulated, which bolt is connected by the wire g. at the point 8" with the coils of
the magnet S. As long as the arc is of normal length, pole 6. does not act upon
the lever F as the magnetism is too weak to overcome the counterpull of the
spring q. but as soon as the arc is no longer normal, through any irregularity
in the shunt mechanism, its (the arc's) resistance increases, consequently to the
same degree the strength of current is augmented in the magnet N'. As soon as
this current strength reaches a certain height, previously determined, so that the
power of the magnet exceeds that of the spring q. the lever F is attracted towards
pole 6. which causes a contact of this lever with the bolt c.
As the lever F¹ is now electrically connected with the positive pole, the course
described under condition 2. is opened to the current, and as it offers less resistance,
than that through the arc, which is, besides, too long, the current will enter it at
once, namely, in the direction of the line from the lever F¹ to the contact bolt c.

page_text: through the coils of the magnet S. over pole 6., spiral W., rod N. to the negative
binding screw O. and off.
The principal advantage of the above described safety arrangement is this,
that the shunt is effected at a relatively small arc, little exceeding the normal
length.
With an arc, on the contrary, which does not yet disturb the remaining arcs
burning in the same circuit, the automatic interruption of the arc would have to
be waited for in order to effect the shunt, and frequently a very long arc,
which would have a great effect upon the whole circuit, would precede this
action.
Should now the shunt mechanism, from any cause, refuse to act, or the carbons
be burned completely out, the resistance W. corresponding to the arc, enters auto-
matically (as shown in the drawing), and consequently the action of the other
lamps is not disturbed..
For the sake of simplicity and to show clearly the principle involved, an arc
lamp construction is chosen for the subject of the said drawing in which only one
of the two carbons is moved by the shunt mechanism, the carbons are placed
vertically above each other, so that their axes fall in one straight line, and the
luminous point is below the mechanism as is usually the case with suspended
lamps. The principle by which the carbons are held and moved permits of their
working towards each other at all possible angles of inclination, even horizontally,
of moving, according to requirements, either both carbons or only one, towards
each other, and of employing currents of the same or alternating directions.
Further, all parts which have hitherto occupied their positions in consequence
of their gravity can be kept in their places by springs or other means.
The sudden approaching movement of the carbons, likewise takes place as
required by the shunt arrangement, under the pressure of a counterbalance, weight
or spiral spring.
But the feeding of the carbons, when alight, however the parts may be arranged,
is effected solely by the shunt mechanism, worked by the shunt electro-magnet or
Bolenoid disposed for automatic current weakening or demagnetisation.
Thus solenoids may take the place of electro magnets in all cases where a more
uniform and more sensitive attraction is desired.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that, what
I claim is
First. In electric arc lamps the method of effecting the feeding of one or of both
the carbons in order to preserve a uniformity of arc by a "shunt" mechanism
moved by an electro-magnet or solenoid placed in the "shunt circuit and disposed
for automatic current-weakening and demagnetisation, substantially as herein before
described.
Secondly. In electric arc lamps, the arrangement of an automatic shunt
mechanism E, m., R., electro magnet S., resistance spiral W., brake lever T. T., with
brake roller r. and spiral spring X, adjusted by spring y, which serves the purpose
of closing the circuit, in case it should be interrupted in its course through the
carbons, at once, by another route and of causing the carbons to approach auto-
matically in the event of extinction or lighting of a lamp in case the carbons
should not be in contact without the aid of the shunt mechanism, substantially as
bereinbefore described and shewn in the drawing hereinbefore referred to.
Thirdly. In the arrangements to set in motion an automatic safety mechanism
consisting of lever F., contact bolt C., spring q. and connecting wire g. through the
electro magnet placed in the "shunt," a disposition which causes the shunt arrange-
ment (referred to in claim 2) to effect the shunting at a length of are previously

page_text: determined, substantially as herein before described and shown in the drawing.
hereinbefore referred to.
And Fourthly. In the construction of electric arc lamps; the combination and
arrangements of parts, substantially as hereinbefore described and set forth.
Dated this twenty sixth day of August One thousand eight hundred and
VAUGHAN & SON,
Agents for the Applicant.