Improvements in Electric Arc Lamps.
Year: 1896

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
We ERNEST JOHN BAGNALL of 37 Oakdale Street and GEORGE ARNOLD
of 1033 First Avenue, both of Cleveland in the County of Cuyahoga and State of
Ohio, U.S.A., Electrical 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 :-
Our invention relates to an improvement in electric arc lamps and more
particularly to such as are adapted to be operated with alternating electric
currents.
In alternating current arc lamps as heretofore constructed the carbons are
arranged in series with the separating and feeding coil and are normally in
contact when no current is passing through the lamp. The coil is provided
with a movable core or armature to which the clutch devices or other mechanical
feeding mechanism, are attached. It is obvious that when current first enters the
lamp it will flow through the coil and carbons. The carbons being normally in
contact, the resistance to the current will be at the minimum and consequently a
heavy current will flow through the coil. This heavy current actuates the magnet
violently giving it such power that it pulls the carbons apart so suddenly as to
rupture the arc. The strength of the magnet will, of course, be destroyed when
the arc is thus ruptured and the carbons will fall together again, closing a circuit
of low resistance through the coil and causing the above operation to be repeated.
Thus a violent and annoying chattering takes place until the carbon points shall
have become sufficiently heated so that an arc can be formed and maintained
between then.
It is the object of our invention to provide means whereby to prevent the
repeated separation of the carbons rupturing of the arc and consequent violent
chattering in an alternating current are lamp."
A further object is to provide means for causing the carbons to be so disposed
for a brief period before the normal arc is struck as to form a very small arc
between them whereby to raise the temperature of the carbon points to a
sufficient degree of heat to cause them to throw off a proper amount of volatilized
carbon to maintain the normal arc.
With these objects in view the invention consists in the combination with the
separating magnet and carbons of an electric arc lamp, of are starting devices
constructed and arranged to cause the carbon points to be sufficiently heated prior
to the formation of the normal are to insure the maintenance of the normal arc
when formed.
The invention also consists in the combination with the separating magnet and
carbons of an are lamp, of are starting devices constructed and arranged to cause
the carbon to be slightly separated for a short period before they are separated
sufficiently to form the normal arc.
The invention also consists in the combination with the separating magnet and
carbons of an arc lamp, of are starting devices constructed and arranged to retard
the separation of the carbons after the current enters the lamp and the carbons
have begun to separate.
And the invention further consists in certain novel features of construction and
combinations and arrangement of parts as hereinafter set forth and pointed out in

page_text: In the accompanying drawings;
Figure 1 is a view showing portions of an arc lamp, with the parts in normal
positions when no current is passing through the lamp.
Figure 2 is a similar view, showing the positions of the parts when the current
enters the lamp and before the normal arc is formed.
Figure 3 is a similar view showing the positions of the parts after the normal arc
has been formed.
Figure 4 is a part view (at right angles) of Figures 1, 2 and 3.
A represents a solenoid which can be supported in the lamp casing in any
suitable manner and preferably disposed in a vertical position so that its core A
will project into a frame B arranged in a fixed position immediately below the
solenoid. The frame 13 is made with a lateral arm 1 having a boss 2 with
which one end of a lever 3 is pivotally connected, said lever being bent at 4 and
made to project within the frame B immediately under the core A' of the
solenoid, to which core the lever 3 is pivotally connected at a point between
the ends of the latter. A clutch rod 5 is pivotally connected to the lever 3 at
a point in proximity to the pivotal point of the latter with the bars 2. The rod 5
depends from its connection with the lever 3 and at its lower end is connected
with a clutch 6 of any preferred form of construction, or a clutch blade 7,
said rod 5 preferably being made in two parts connected together by means of
a turn buckle 8, by which latter the length of the rod can be adjusted. The
holder 9 for the upper carbon 10 is connected with the clutch blade 7 and the
lower carbon 11 is carried by any suitable devices not shown.
The lower half of the frame B Fig. 4. is split to form arms 12, 14 disposed
parallel with the arms of the frame. The arms 12, 14 are made with screw
threaded recesses which constitute bearings for a horizontally disposed screw 16.
A screw 17 is mounted in a similar manner between the arms 13, 15 and slightly
above a line passing through the screw 16. A lever 18 is disposed within the
frame B and made with a V-shaped recess 24 in which the conical end 26 of
the screw 17 has a bearing, said conical end 26 thus forming the end of the
lever. Opposite the recess 24 another V-shaped recess 25 is made in the lever 18
for the reception of a conical head 27 which is loosely connected at one end of a
rod 28. A similar hend 29 is loosely connected to the other end of the rod 28 and
has a bearing in the inner end of the screw 16. A spring 30 encircles the rod 28
and bears at its respective ends against the heads 27, 29. The lever 18 is
prevented from escape from its bearings by means of nuts. The lever 18 is
made with an upwardly extending curved arm which terminates at its lower end
in a flat reat to one side of the fulcrum of the lever, and with this curved arm and
seat the free end of the lever 3 is adapted to engage in a manner hereinafter more
fully explained. The short arm of the lever 18 projects downwardly and slightly
laterally from the pivotal point of the lever and constitutes a foot 22 adapted,
when the parts are in their normal positions, (with no current passing through
the lamp) to engage an adjustable stop 23, as shown in Figure 1.
From this construction and arrangement it will be seen that when the parts are
in their normal positions, with no current passing through the lamp, the axis of the
spring 30 will be out of line with the axis of the screw 17 and below the fulcrum
of lever 18 so that the force of said spring will be exerted on said lever to cause
the foot 22 to bear against the adjustable stop 23. When the parts are in this
position, the curved arm of lever 18 will project toward the core A of the solenoid,
the said core will be in its lowest position and the free end of the lever 3 will rest
on the seat of lever 18, as shown in Figure 1. It is evident that when the core of
the solenoid rises, carrying the lever 3 with it, the engagement of the free end of
said lever with the curved arm of lever 18 will cause the latter to turn on its
fulcrum, and that when the lever 18 has been moved to a sufficient extent to cause
the head 27 at the end of the spring 30 to pass above the fulcrum of said lever
and the axis of the screw 17, said spring will exert a pressure on the 1 ver 18 to
cause the curved arm to complete its rearward movement, pass out of line with the

page_text: free end of the lever 3 and rest against an adjustable stop 31. The stop 31 should
be so adjusted that when the curved arm 19 is resting against it, the free end of
said curved arm will be just out of line with the free end of the lever 3. When
the core of the solenoid moves down (as when the lamp is cut in and out of circuit
and the solenoid de-energized) the free end of the lever 3 will pass the free end of
the curved arm 19 and strike the scat 20, thus causing the lever 18 to turn
sufficiently to bring the head 27 on spring 30 to pass below the fulcrum of the
lever 18, when said spring will cause said lever 18 to return to its normal position
as shown in Figure 1. The above description explains the mechanical operation
of our improvements. Their electrical operation and importance in the successful
operation of an are lamp for use with an alternating electrical current will next be
explained.
As above mentioned, one of the most objectionable features in the operation of
an arc lamp with an alternating current, is the annoying chattering caused when
the lamp is started, and this chattering is largely due to the repeated breaking and
making of the circuit between the carbons during the time the points of the
carbons are becoming sufficiently heated to insure the maintenance of the normal
are. It is known that before the normal arc can be maintained when an alternating
current is employed the carbon points must be sufficiently heated to throw off a
certain amount of volatilized carbon. In alternating current are lamps the
separating solenoid or magnet is included in series in a normally closed circuit.
with the carbons, so that when the current first enters the lamp the resistance
is so low that a heavy current passes through the solenoid or magnet and
causes it to become so strong as to violently separate the carbons to their full
extent for a normal arc and before the points of the carbons can have possibly
become sufficiently heated to cause the maintenance of the normal are.
are is therefore ruptured and the circuit instantly broken, thus depriving the
solenoid of its energy and permitting the carbons to again come together and
close the circuit through the solenoid, the result of which is to again violently
separate the carbons.
The
These operations, with the consequent annoying chatter will continue until the
temperature of the points of the carhons shall have reached such a degree as will
cause them to throw off sufficient volatilized carbon to insure the maintenance of
the normal arc. By means of my improvements I avoid these continuous violent
separations of the carbons and consequent breaking of the circuit with accompanying
chatter, and this result I accomplish by causing a small preliminary are to be formed
and maintained for a sufficient length of time to properly hent the carbon points to
insure the maintenance of the subsequently formed normal are. The action of the
parts in the performance of these functions is as follows:
The parts, when no current is passing through the lamp, assume the positions
shown in Figure 1, with the carbons in contact with each other. Current being
How male to pass through the lamp, the coil or solenoid will be energized and its
core will begin to rise, causing the clutch to grip the clutch blade and begin to
separate the carbons. The core A' will rise only a very short distance however,
when its further ascent will be arrested by the engagement of the lever 3 with the
curved arm of lever 18, but the carbons have been slightly separated, (see
Figure 2) sufficiently to permit the formation of a small are between them. The
core continues to move upwardly against the resistance offered by the spring 30,
and maintain the small are for a sufficient length of time to permit the carbon
points to become properly heated to maintain a normal arc-at which time the
head 27 at the end of spring 30 will have moved past a line common to the axis of
the screw 17 and above the fulcrum of lever 18, whereby to cause the lever 18 to
complete its movement (Figure 3) and set free the lever 3 and core A¹. when the
latter will complete its upward movement within the coil A and effect a separation
of the carbons sufficient to form a normal are which will be maintained. Sufficient
range of movement of the lever 3 without engaging the lever 18 will be permitted
to allow a proper feeding of the carbons but when the lamp is cut out of circuit the

page_text: core will drop and engage the seat 20 of lever 18, causing said lever to assume its
normal position (Figure 1) as above explained, ready to be operated when the
lamp is again started.
Various slight changes might be made in the details of construction of our
invention without departing from the spirit thereof or limiting its scope and hence
we do not wish to limit ourselves to the precise details herein set forth.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is:
1st. The combination with the separating magnet and the carbons of an arc
amp, of are starting devices sn constructed and arranged as to cause the carbons to
be sufficiently heated before the formation of the normal are to insure the
maintenance of said normal are when formed, substantially as set forth.
2nd. The combination with the separating magnet and carbons of an are lamp,
of are starting devices constructed and arranged to cause the carhons to be slightly
separated for a short period before they are separated sufficiently to forin the normal
are, substantially as set forth.
3rd. The combination with the separating magnet and carbons of an are lamp, of
are starting devices constructed and arranged to form a small are between the
carbone before the formation of the normal are, substantially as set forth.
4th. The combination with the carbons of an are lamp, and a separating magnet,
of are starting devices intermediate of said carbons and the separating magnet so
constructed and arranged that when current enters the lamp the carbons will be
first slightly separated to form a small are for heating the carbon points and then
separate the carbons to form the normal are, substantially as set forth.
5th. The combination with the separating magnet and carbons of an are lamp, of
are starting devices constructed and arranged to retard the formation of a normal
are after the carbons have begun to separate, substantially as set forth.
6th. In an are lamp, the combination with the carbons, a magnet and a lever
connected with said carbons and the armature of the magnet, of devices adapted to
engage the lever and retard the formation of a normal arc after the carbons begin
to separate, substantially as set forth.
7th. In an are lanp, the combination with a separating magnet, and the carbons,
of a pivoted lever connected with the armature of said magnet, a connection
between said lever and the carbons, a curved lever normally disposed in the path
of the first-mentioned lever and a spring bearing against said curved lever and
adapted to control the movements of the same, substantially as and for the purpose
set forth.
8th. In an are lamp, the combination with the earbons and a magnet in serios
with said carbons, of a pivoted lever connected with the armature of said magnet,
a connection between said lever and earhons and a spring actuated retarding device
adapted to be engaged by said lever and to release said lever, successively, substan-
tially as set forth.
9th. In an arc lamp the combination with a magnet and the carbons of a lever
connected with the armature of said maguet and with the carbons, of a spring
actuated retarding lever adapted to be engaged by said first mentioned lever and
adjustable stops constructed and adapted to limit the movements of said retarding
lever, substantially as set forth.
10th. In an are lamp, the combination with a magnet, and the carbons of a lever
connected with the arinature of said magnet and with the carbons, a retarding lever
to be engaged hy the first mentioned lover, and a spring constructed and adapted
to bear against said retarding lever, and retain it in the position to which it may be
anoved, substantially as set forth.
11th. In an are lamp, the combination with a magnet, and the carbons, of a
lever connected with the armature of the magnet and with the carbons, a retarding
lever adapted to be engaged by said first-mentioned lever and a spring bearing

page_text: against said retarding lever normally at one side of its fulcrum, substantially as set
forth.
12th. In an arc lamp, the combination with a separating magnet, and the carbons
of a pivoted lever connected with the carbons and with the armature of the magnet,
a retarding lever adapted to be engaged by the first-mentioned lever, a pivotal
bearing for said retarding lever, a spring adapted to normally bear against said
retarding lever at one side of its fulcrum, a foot on the retarding lever and a stop
to be engaged by said foot, substantially as set forth.
13th. In arc lamp, the combination with a separating magnet, and the carbons,
of a pivoted lever connected with the armature of the magnet and with the carbons,
a retarding lever, adapted to be engaged by said first-mentioned lever, a screw
forming a pivotal bearing for said lever, a spring having a bearing at one end
against the frame of the lamp and a head at the other end of said spring having a
bearing in a recess in the retarding lever at one side of its fulcrum, substantially as
set forth.
14th. In an arc lamp, the combination with a separating magnet and the carbons,
of a pivoted lever connected with the armature of the magnet and with the carbons,
screws in diametrically opposite arms of the lamp frame, said springs being out of
line with each other, a retarding lever to he engaged by the first mentioned lever
and having one of said screws for its fulcrum, a spring, and heads at the ends of
said spring, one of said heads having a bearing in one of said screws and the other
head having a bearing against the retarding lever normally at one side of the
fulerum thereof, substantially as set forth.
15th. In an are lamp, the combination with a separating magnet and the carbons,
of a pivoted lever connected with the armature of the magnet and with the carbons,
a retarding lever having a pivotal bearing in the lamp frame, said retarding lever
having a curved arm to be engaged by the first mentioned lever, a seat on the
retarding lever to one side of its fulcrum to be engaged by the first-mentioned
lever and a spring adapted to bear against the retarding lever normally at one side
of its fulcrum, substantially as set forth.
Dated this 28th day of January 1896.
HERBERT HADDAN & Co.,
18 Buckingham Street, Strand, London, W.C.,
Agents to the Applicant.