Improvements in Electric Arc Lamps.
Year: 1893

page_text: Date of Application, 28th Feb., 1893-Accepted, 17th June, 1893
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
I, BARTON BREWER WARD, of 18 Cortland Street, in the City, County and
State of New York, U.S.A., 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 electric arc lamps designed for use on what are termed
constant potential circuits between whose mains incandescent lamps or other trans-
lating devices are connected in parallel while an approximately constant difference
of potential is maintained between the mains. This difference of potential is
usually considerably greater than that required to maintain the arc of a single
electric arc lamp, and it hence becomes necessary in burning arc lamps on such
circuits to either run two or more arc lamps in series with one another in each
branch or connection across the mains, or else, when a lesser number is run, to cut
down the surplus potential by an interposed useless and wasteful resistance.
In describing my invention I will assume that the potential of the mains is 100 to
110 volts, the standard at present in use for incandescent lamp circuits. It will
be understood, however, that the invention is applicable to circuits of greater
potential or even less provided the potential is in any case sufficient to maintain
two arcs at least.
A standard arc lamp as ordinarily run is designed to pass approximately 8 to 10
ampères of current, and the voltage for maintaining the arc of the ordinary length
is approximately one half that provided by the mains. Hence it is the practice to
run two lamps each giving the standard illumination in the same branch, but when
the standard illumination of one lamp only is desired it is necessary to interpose an
artificial resistance in the branch with the lamp.
One of the aims of my invention is to provide a lamp that may be used on such
a constant potential circuit as an efficient and economical substitute for the ordinary
lamp giving the standard light, but without the use of any considerable dead
resistance taking the place of a second lamp burned in the same branch.
Briefly speaking my invention consists of a double or multiple arc lamp having
two or more independent regulating mechanisms, and two or more corresponding
feed controlling magnet systems in continuous operative connection with the electric
circuit.
A lamp thus constructed and run on a 110 volt circuit could be made to pass
say 4 to 5 ampères of current through each of its two sets of carbons constantly
burning in series, and would then give as much or even more light than a single
8 to 10 ampère lamp, and could hence he used as an economical substitute for a single
lamp giving the standard illumination, since the two arcs would substantially use
up the whole voltage and wasteful resistance would be unnecessary.
It is well known that an ordinary single are will use up from 45 to 50 volts, so
that when burned upon a 110 volt circuit the remaining voltage must be taken up
by a resistance of some kind. This is the practice where a single arc is used, but
if two arcs be used it will be obvious that twice as much voltage is taken up by the
arcs themselves, that is to say, from 90 to 100. Thus the second lamp takes up
substantially all the voltage which, if a single lamp be used, would have to be
taken up by dead useless resistance.
Another advantage of a lamp constructed in accordance with my invention is
that the light produced for a given consumption of electric energy would be better
distributed. The lamp also permits of the simultaneous burning of two sets of
carbons in reversed connection that is with the lower carbon of one pair used as a

page_text: positive while the upper of the other pair is used at the same time as a positive.
Hence my invention provides a lamp especially suited to photo-engraving or other
purposes where a more uniform distribution of the light is desired than could be
obtained by a lamp in which a single crater exists throwing the light mainly in one
direction only.
When the voltage permits it will be obvious that the lamp might have a larger
number than two sets of carbons and feed mechanisms operating at the same time,
and that if desired the lamp might be made to consume only the normal amount of
energy and give only the illumination of a standard lamp, by constructing it to pass
a correspondingly less number of ampères.
Other novel features of my invention will be more particularly specified in the
claims.
In the drawings I have illustrated my invention as embodied in a double carbon
lamp.
In Fig. 1, of the drawings, the lamp is shown from one side in elevation.
Fig. 2, is a diagrammatic front elevation showing the two sets of carbons and
the two corresponding sets of regulating magnets together with a switch magnet
which is combined with said two sets and employed in the manner hereinafter
described.
Fig. 3, is a vertical section through the lower end of the frame of the lamp
where the two lower carbons are supported.
Fig. 4, shows the switch magnet in elevation.
Fig. 5, is a plan of the armature used with said magnet.
Fig. 6, is a plan of the magnet itself with the contacts supported thereon.
Fig. 7, illustrates a modification of the connections.
Fig. 8, illustrates a modification of the manner of operating the lamp.
Fig. 1, shows the mechanism for one pair of carbons. A view of the lamp from
the opposite side would be substantially the same with the switch magnet omitted.
A, B, indicate one pair of carbons and A2, B2, a second pair.
C, is the main circuit regulating magnet for the first pair and D, the derived
circuit magnet for the same pair. While I have shown two regulating magnets
(main and derived) for controlling the feed of the carbons in the usual manner, I
do not limit myself to the use of magnets combined in the particular way herein
shown. The said magnets, as indicated, are provided with movable cores attached
to opposite ends of the feed regulating lever E, which supports the usual mechanism
gearing with the carbon carrier and adapted to lift the carbon or permit it to feed
down according to the requirements. The feed mechanism here shown is the
ordinary clock-work feed and need not be described in detail since any other clock
work feed or any other regulating device may be used in place thereof.
The mechanism for the two pairs of carbons may be substantially the same or
may vary as desired. The mechanism of each pair is properly mounted on au
insulating support or base in the frame F, of the lamp and the electric connections
are formed with the upper and lower carbons through the frame and the regulating
mechanisms and by the attachment of proper conductors, as well understood in
the art.
Main and derived circuit magnets for the second pair of carbons A², B³, are
indicated at C, D, in the diagram Fig. 2. The side rods of the lamp, indicated
at G, support at their lower end in the proper cross pieces, the two lower carbon
holders H, H.
These holders are mounted in the cross bar in the manner indicated in Fig. 3.
They are insulated from one another in proper bushings, as shown, of insulating
material secured in openings in the cross frame and are fastened in place therein by
suitable nuts I, which engage with the lower ends of the tubular carbon holders
beneath the cross frame. These metal nuts may also serve to clamp plates I,
which are secured to the ends of conductors by which proper connections are made
with the lower carbon holders. By thus mounting the lower carbon holders and
making proper connections with the same, the two sets of carbons may be included

page_text: in series with one another as indicated by the diagram and as will be presently
described.
K, indicates a switch magnet which is included in the series circuit with the two
carbons and normally holds closed a switch having two sets of contacts that normally
complete the circuit for the derived magnets D, D', putting each derived circuit
magnet into proper shunt connection with its own or corresponding pair of carbons.
When the circuit is interrupted through the carbons, however, the switch magnet K,
loses its power and the connection of both magnets D, D2, with the circuits of the
lamp is interrupted so that no current may pass through them when the lamp is out
of operation. The switch by which this is accomplished may be constructed as
illustrated in the detail figures. The armature lever of the magnet K, is indicated
at P, and is pivoted rather loosely at the point 6, being provided, however, with a
proper retracting spring which tends to hold the armature P2, away from the pole
of the magnet K. The armature supports the cross piece of conducting material
indicated at R, which, at its opposite sides, carries contact points adapted to engage
with contact plates S, S2, which are properly mounted on a plate of insulating
material on the top of the magnet so as to be out of connection with one another
excepting through the connecting switch plate R, and the switch contacts carried
thereby.
The plates or contacts S, S', connect respectively with one terminal of the derived
circuit magnet coils D, D2, the opposite terminals thereof being connected as shown
in the diagram with the two terminals of the lamp in any proper manner.
The switch bar or connector R, is in electrical connection with the armature lever
itself and the latter is properly mounted on a post T, and in electrical connection
therewith. Suitable attachments of the wires of the lamps are inade, as shown, in
the diagram Fig. 2, so as to form the connections therein illustrated. Starting
from one terminal of the lamp indicated by the sign positive the main circuit passes
through the magnet C, and through the pair of carbons A, B, to the post T, at
which point connection exists with one terminal of the derived circuit magnet D,
for the set of carbons A, B, when the switch lever is pulled down by means of a
magnet K the main circuit continues by way of the coils of K, through the main
circuit magnet C', and by way of the second pair of carbons A2, B2, to the terminal
of the lamp marked negative. The connection of the derived circuit magnet D³,
for such second pair is formed through the switch R, when the armature lever_P²,
is drawn down so that the same will be in derived circuit to said second pair. The
attachment of the two derived circuit magnets D, D', to the terminals of the lamp
are obvious from inspection.
When the lamp is in operation the main circuit magnet K, being excited by
the current passing through the two pairs of carbons, holds down the armature
lever P, and closes the two switch contacts at the opposite ends of the bar R, on
the contact S, S2, the lamp being then in operative condition so far as all of the
circuits are concerned and each of the derived circuit magnets D, D', operating in
conjunction with its own main circuit magnet C or C2, and its own pair of carbons,
in proper manner to permit the two pairs of carbons to burn and adjust themselves,
as well understood in the art. If, however, the main circuit becomes interrupted
through burning out of the carbons then the magnet K, loses its power and the
connection of both derived circuit magnets D, D2, with the circuit of the lamp is
interrupted so that current may not pass through either of them while the lamp is
out of operation.
It will be obvious that instead of placing the switches for the two magnets D, D',
at the point indicated between such magnets, they might be interposed in the
circuit between the magnets D, D2, and the terminals of the lamp.
This modification I have illustrated by the detail diagram Fig. 7.
In this
instance, however, it will be necessary to insulate the two ends of the cross-bar R,
from one another, as shown, and to make connection with said ends and with the
terminals of the lamp or with the magnets D, D3, in circuit.
Should it be desired to burn the two pairs of carbons with the upper of one

page_text: pair as a positive, while the lower of the other is a positive, it is obviously only
necessary to change the connections so as to reverse the direction of the flow of
current through one pair as heretofore traced and as indicated in the diagram
Fig. 8.
In the diagram Fig. 2, the constant potential mains are indicated by the
numerals 10, 10.
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 what I
claim is :-
1. A multiple carbon lamp having two or more independent regulating
mechanisms and correspondingly simultaneously burning pairs of carbons, two or
more corresponding feed controlling magnet systems in continuous operative con-
nection with the electric circuit, and a frame common to said pairs of carbons and
magnet systems, as and for the purpose described.
2. A double or multiple carbon lamp having a frame F, G, G, two or more sets
of carbons burning simultaneously in series with one another, with the lower
carbons both supported in the cross piece of the side rods G, G, two or more
corresponding independently operating regulating mechanisms for said carbon, and
two or more corresponding feed controlling magnet systems in continuous opera-
tive connection with the electric circuit and mounted in the frame F, as and for
the purpose described.
3. In a double carbon lamp, the combination, substantially as described, with
the two simultaneously burning pairs of carbons aud the two corresponding sets of
main and derived circuit regulating magnets in continued operative connection with
the circuit, of switch devices by which the operative connection of each derived
circuit magnet in the lamp is normally maintained, and a magnet in the main circuit
with the two pairs of carbons for holding the two sets of contacts of said switch
devices normally closed.
4. The combination with constant potential mains, of an electric arc lamp having
the voltage of the mains subdivided in a number of pairs of simultaneously but
independently fed and adjusted pairs of carbons run in series with one another, and
corresponding in number to the voltage or potential, the lower carbons of said
pairs being mounted in a cross bar of the side rods of the lamp and insulated from
one another on said cross bar, as and for the purpose described.
Dated this 17th day of February 1893.