Improvements in Electric Arc Lamps.
Year: 1896

page_text: Date of Application, 19th May, 1896--Accepted, 26th Sept., 1896
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
I, ERNEST JOHN BAGNALL, of 37 Oakdale Street Cleveland in the County of
Cuyahoga and State of Ohio United States of America 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 relates to an improvement in electric arc lamps, and more
particularly to such as are adapted for use with alternating electric currents.
Electric arc lamps for use with alternating currents are constructed with a single
coarse wire magnet arranged in series with the carbons, so that when the current
enters the lamp the full current flows through the helix of said magnet and the
carbons, which latter are of course normally in contact when no current is passing
through the lamp. The current finding, when it first enters the lamp, an
unobstructed path through the helix of the magnet, the latter will be energized
to a great extent, and, if no means be provided to prevent it, will attract
its armature so vigorously that the carbons connected with said armature, will be
violently separated to their full extent for the normal arc.
When an arc lamp is operated with an alternating current it is very essential
that the carbon points be heated to a proper extent before the normal are can be
maintained.
With lamps as heretofore .constructed this has not been accomplished and the
result has been that when the current first entered the lamp, the carbons were
violently separated to their full extent as above explained, and the carbon points
not having been sufficiently heated to maintain the normal are, the latter was
destroyed almost instantaneously with its formation, thus breaking the circuit
through the lamp; de-energizing the magnet and permitting the carbons to come
together and again complete the circuit. The carbons will then be again violently
separated as before and this separating and coming together of the carbons will
continue until they shall have become sufficiently heated to maintain the normal
arc, during which time the rapid and violent movements of the parts will keep
up an annoying chatter, to say nothing of the excessive wear on the mechanism
of the lamp.
It is a matter of great importance to the successful operation of arc lamps
employing alternating currents, especially when the lamp is first started, that the
slightest variations in the strength of the magnet be promptly and accurately
transmitted to the carbons; in other words, the movements of the carbons
relatively to each other should be coincident with every movement of the armature
of the magnet or core of the solenoid however slight the variations may be, and it
is also important that the separation of the carbons to their full extent be so
retarded as to permit them to become sufficiently heated to maintain a normal arc
before such arc shall have been formed, otherwise the chatter and wear above
alluded to will be the inevitable result.
It is the object of my invention to so construct an alternating current arc lamp
that the variations of the separating and feeding magnet will be accurately
transmitted to the carbons and so that the separation of the carbons to their full
extent to form a normal arc shall be sufficiently retarded to permit the carbons to
become properly heated to maintain the normal arc when formed.
With this object in view the invention consists in the combination with the

page_text: solenoid of an alternating current are lamp and a clutch, of means forming a direct
connection, without interpused yielding devices, between the core of the solenoid
and said clutch, whereby the slightest variation in strength of the solenoid will be
promptly and accurately transmitted to the carbons, a retarder and a non-limited
yielding connection between said retarder and the core of the solenoid whereby to
retard the separation of the carbons in forming the normal are when the lamp is
being started.
The invention also consists in the combination with the separating and feeding
magnet of an alternating current arc lamp and the carbons, of an armature lever
connected directly with the armature of said magnet and with the carbons without
interposed yielding devices, a retarder, and a yielding device forming the sole
connection between said retarder and armature lever.
The invention also consists in the combination with a solenoid and the carbons
of an alternating current are lamp, of a pivoted armature lever pivotally connected
directly to the core of said solenoid, a clutch for the carbons connected directly
with said armature lever, an air pot, and a spring secured at one enl to the
armature lever and attached at the other end to the plunger of said air pot, said
spring constituting the sole connection between the arinature lever and plunger of
the air pot.
And the invention further consists in certain novel features of construction and
combinations and arrangements of parts as herein after set forth and pointed out
in the claims.
In the accompanying drawings;
Figure is a view of an electric arc lamp showing the application of my
improvements.
Fig. 2 is an enlarged view of the separating and feeding magnet and parts
connected therewith.
Fig. 3 is a view of certain details.
Fig. 4 is a view of a modification.
A represents the lamp casing; B the globe holder; C the globe and D the
hollow lamp arm projecting downwardly within the globe. A tube 1 and a rod 2
are disposed parallel with each other within the casing A, and between them a
vertically movable cross head 3 is guided. The holder 4 for the upper carbon 5
is secured to and projects laterally from the cross head 3, and the holder 6 for the
lower carbon 7 is connected with the lower end of a rod 8 which passes upwardly
through the lamp arm and terminates within the tube 1. A chain 9 is connected
at one end with the rod 8 and after passing over a pulley 10, is connected at its
other end to the cross head 3. A clutch blade 11 is also secured to the cross
head 3 and projects downwardly into the hollow lamp arm.
A coarse wire solenoid E is secured to the enlargement 12 on the under face of
the roof of the casing A. To the lower head of the solenoid, a plate 13 having
a curved arm 14 is secured, said arm preferably having an enlargement 15 at its
free end to serve as a stop for an armature lever 16. The armature lever is pre-
ferably made with a yoke 17 through the arms of which a pin 18 passes, said pin
also passing through the arm 14 and pivotally connecting the said armature lever
thereto. The free end of the armature lever 16 is pivotally connected directly to
the core 19 of the solenoid E and to said armature lever at a point in close
proximity to its pivotal support, a rod 20 is pivotally connected by means of a pin
or screw 21. The rod 20 depends from its connection with the armature lever and
at its lower end is connected directly with a clutch 22 of any preferred form of
construction, which clutch is adapted to grasp the clutch blade 11 above
alluded to and separate and feed the carbons when the armature lever is
actuated.
A plate 23 is secured to the upper end of the solenoid E and provided with an
arm 24, to the free end of which an air pot 25 is pivotally connected. A com-
paratively loose plunger 26 operates in the air pot and to said plunger a rod 27 is
secured. The lower end of the plunger is pivotally connected to the free end of

page_text: a flat spring 28, the other end of said spring being secured to the armature
lever 16.
From the construction and arrangement of parts above described it will
be seen that the core of the solenoid is connected with the clutch without the
intervention of any springs whatever, so that the slightest movement of the said
core or armature will be transmitted to the carbons and there reproduced, so that
the movements of the carbons will be exactly coincident with the movements of
the core of the solenoid, the said core answering promptly and accurately to the
slightest variations in strength of the solenoid, and, as has been demonstrated by
actual experiment, this is a matter of much importance in the successful operation
of the are lamps with alternating currents.
With my improvements, when the current first enters the lamp, the solenoid will
have a tendency to quickly pull up its core and suddenly separate the carbons, but
this will be prevented by the retarding action of the air pot, sufficient movement of
the core and the carbons connected therewith will, however, be permitted by the
resilience of the flat spring 28 to allow the carbons to separate enough to form a
small are which will serve to heat their points. The cold carbon points constitutes
a great resistance to the formation of the normal arc in an alternating current lamp,
and, with my improvements this resistance will gradually decrease as the carbon
points become heated, and when they shall have reached such a temperature as to
no longer form such a resistance, the normal are will be formed and maintained.
without interruption.
I am aware that devices have been proposed for effecting the successful starting
of alternating current are lamps, in which springs have been interposed between
the core of the solenoid and the carbons but such constructions have not, as a rule,
met with complete success, principally because the movements of the core of the
solenoid could not be accurately transmitted to the carbons.
With such prior constructions, when the core rises, the spring connected
therewith will yield before the movement of the core will be transmitted to
the carbons and consequently the rapid reciprocations of the core will be entirely
out of time with the movements which are transmitted to the carbons, thus delaying
and complicating the starting of the lamp and the subsequent feeding of the
carbons. With my improvements all this is obviated and the starting of the lamp
as well as the subsequent feeding of the carbons are successfully accomplished
without the accompanying chatter and wear of the parts heretofore experienced.
I have demonstrated by practical experiment that with the improvements above
described, the lamp will start in a remarkably short time and that subsequent
flickering, so common to alternating current lamps as heretofore constructed, is
entirely avoided.
In the form of the invention shown in Figure 4, the armature lever 16 is
pivotally connected directly to the core of the solenoid, and the free end of said
lever is connected with the plunger of the air pot, through the medium of a coiled
spring 29. Other modifications in details of construction might be made so long
as the core of the solenoid is connected with the carbons without intervening
yielding devices and the arinature lever connected with the plunger of the air pot
through the medium of a spring.
Having now particularly described and ascertained the nature of this said inven
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In an alternating current are lamp, the combination with a solenoid and a
clutch, of means forming a direct connection without interposed yielding devices,
hetween the core of the solenoid and said clutch, whereby the slightest variation in
strength of the solenoid will be promptly and accurately transmitted to the carbons,
a retarder and a non-limited yielding connection between said retarder and the core
of the solenoid whereby to retard the separation of the carbons in forming the
normal are when the lamp is being started, substantially as set forth.

page_text: 2. The combination with the separating and feeding magnet of an alternating
current are lamp and the carbons of an armature lover connected directly with the
arinature of said magnet and with the carbons, a retarder and a spring forming
the sole connection between said armature lever and the retarder, substantially as
set forth.
3. The combination with the separating and feeding solenoid of an alternating
current arc lamp and the carbons, of a pivoted lever attached directly to the core
of said solenoid and with the carbons without interposed yielding devices, a
retarder, and a spring forming the sole connection between said pivoted lever and
the retarder, substantially as set forth.
4. In an arc lamp, the combination with the separating and feeding solenoid, of
an arm secured to the frame of said solenoid, a lever pivoted to said arm and
connected to the core of said solenoid, an air pot supported by the frame of the
solenoid and a spring secured at one end to said armature lever and attached at
the other end to the plunger of sail air pat, sul stantially as set furth.
5. In an are lamp, the combination with a separating and feeding solenoid, and
a curved arm secured to and depending from the frame there f, of a lever pivoted
between the ends of said arm and pivotally connected to the core of the solenoid,
the free end of said arm constituting a stop for said lever, an air pot, and a spring
secured at one end to said lever and attached at its other end to the plunger
of said air pot, substantially as set forth.
6. In an alternating current are lamp, the combination with the separating and
feeding magnet, of a vertically movable cross head, guides for said cross head. an
upper carbon holder carried by the cross head, a movable lower carbon holder,
flexible connections between the lower carbon holder and said cross head, a clutch
blade secured to the cross-head, a clutch to grasp said clutch blade, a pivoted
armature lever connected directly with the core of the solenoid and with the
clutch, an air pot and a spring secured at one end to the armature lever and
attached at the other end with the plunger of the air pot, substantially as
set forth.
Dated this 19th day of May 1896.
HERBERT HADDAN & Co.,
18, Buckingham Street, Strand, London, W.C., England,
Agents for Applicant.