Improvements in Electric Arc Lamps.
Year: 1898

page_text: Date of Application, 10th June, 1898-Accepted, 17th Sept., 1898
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
We, THE BRITISH THOMSON-HOUSTON COMPANY, LIMITED, of 83, Cannon Street,
in the City of London, Electrical Engineers, do hereby declare the nature of this
invention (which has been communicated to us from abroad by Richard Fleming,
of Lynn, in the County of Essex, State of Massachusetts, United States of
America, Electrical Engineci), and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement.-
The present invention relates to are lamps, and particularly those designed for
use on alternating-cuirent circuits, wherein the arc is confined in a small chamber,
and has for its object to improve the construction and arrangement of the lamp
mechanism
In the accompanying diawings, Fig 1 is a side elevation of my improved lamp,
with certain portions indicated in section, Fig 2 is a diagram of the cucuit con-
nections, Fig 3 is a modification of the means employed for ventilating, and
Figs 4 and 5 are details of the actuating magnets.
The main body of the lamp comprises a rectangular cast metal fiame A to which
is screw-threaded at its upper end a tube B, this tube furnishes a support for the
metal top C, and at the same time surrounds and protects the upper carbon
pencil D On the upper end of the tube is mounted a cap C¹ which is provided
with an insulating spool C³ for insulating the suspension ng C' from the body
of the lamp Mounted in the metal top are binding posts Land E' these posts
are insulated from each other and the top by insulating bushing and collais in
the ordinary manner The circuit through the lamp 18 controlled by means of
the switch Es which is mounted on the top of the lamp and is insulated there-
from
Situated duectly under the cover and secured thereto by the screws is a react-
ance F comprising a cucular laminated core I that is surrounded by a number of
tuins of insulated wire F One end of the reactance coil is connected to switch E³,
and the other end is connected by the insulated wue E³, which extends down the
side 1od of the lamp, with the lower carbon-holder and carbon
The action of the lamp is controlled by a pair of selles-wound magnets G
and G, these magnets are mounted on four vertically-extending guide-rods G³
which are secured to the frame casting at their upper ends, and to head G³ at their
lower ends To reduce the vibration and humming due to the alternations of the
current, each coil rests on a pair of coiled springs H which surround the guide-
rode G³, these springs are slightly compressed as the coils are energized and the
carbons separated
Extending across the top of the coils and secured to the upper part of the frame,
is a stationary laminated core I, as shown in Figs 1 and 4 Mounted for move-
ment within the coils G and Gs a U-shaped laminated magnet I so arranged
that when no current is flowing in the coils, it rests on the head G³, but as the
coils become energized, it moves upward toward the stationary core I As the
pull on core I becomes greater as the moving and stationary parts of the core
13

page_text: approach each other, a compensating support is provided for the moving core,
which is so arranged that as the pull of the magnets increases, its supporting
effect decreases By this arrangement, the magnets are made to exert a piactically
uniform pull throughout the range of movement To accomplish this, a tension
spring is provided, which 19 attached at its upper end to the frame of the lamp,
and at its lower end to a support L which is secured to the tube J, suitable means
being provided for adjusting the tension of the spin
In electro-magnets designed for alternating-current work, it has been found
that if a piece of metal forming a closed cucuit is placed within the field induced
by the coils, eddy cuments more or less great will be induced in the metal, this
gives rise to undue heating, and to prevent this the portions of the metal support
which are located in the magnetic field are slotted as shown in Figure 5. "The
we forming the coils is wound on spools in the ordinary manner, and the heads
of the spools are split at g¹ In order to properly support the wire on the spools,
the heads are provided with projections which extend to the outer edges of the
coil Each coil is provided with top and bottom slotted heads, and extending
through these heads are the guide rods G which permit the coils to move slightly
in a vertical direction on their spring supports, but prevent them from twisting
out of parallelism.
"
The support L for moving the upper carbon comprises a split metal ring which
surrounds the tube J and is insulated therefrom by an insulating bushing L³, and is
provided with an upwardly-extending hooked arm L₁ and a projection L' which
supports the core To damp the action of the support, a dash-pot M is provided,
the cylinder being carried by the moving support L, and the piston by the head G³.
Between the projection L3 of the support and the core I' is a compression spring I
to soften the action of the magnet on the carbon D
The tube surrounds the upper carbon pencil D, and supported by the tube
is a clutch J which works directly on the carbon pencil The clutch may be
of any desired construction, the one shown being made of two Jaws J and J³
which are pivotally secured together, and suspended by links from the collar J
Situated underneath the head G, and insulated therefrom, is a metal plate T,
which centres the tube J, this plate may readily be removed when worn, and a
new one substituted In addition to centering the tube, the plate and insulation
act as a check to prevent the passage of gas and hot air up through the lamp
mechanism
The action of the lamp is as follows: when the current enters it energizes the
coils G and G¹, this causes them to attract their core I', and as the power of the
magnets increases, the power of the spring K decreases, so that a uniform pull
is maintained on the tube J As soon as the tube has moved a certain distance,
the clutch will grip and raise the carbon and draw the arc So long as the proper
As the
circuit relations exist, the carbon will continue to burn in its normal manner,
but as soon as the are gets abnormally long, the magnets will become weaker,
and the core will be lowered so that the arms of the clutch will stike the cap of
the enclosing globe and permit the carbon pencil D to feed by gravity
core I' is lowered, the tension on the spring K becomes greater, and it assists the
magnets to a greater degree, the dash-pot M preventing the too rapid movement
of the parts
In certain types of lamps, particularly those in which the enclosing casing rests
duectly on the globe, the heat and gas produced by the arc will, if unrestrained,
pass upward through the lamp mechanism, change or destrov the adjustment,
and corode the parts To prevent this, heads G and G are provided, situated
between the lamp parts and the globe 0, so placed as to afford a dead air space or
chamber N Instead of leaving the chamber empty, it may be filled with asbestos
or other similar material, as shown in Fig 3. In this figure, the construction of
the heads is slightly modified, and instead of being formed integially with a hub
between them, as in Fig 1, they are made separately and held together by screws,
suitable space blocks P being provided between them. With this construction,

page_text: one of the heads G³, G is secured to the side rods to hold the whole in place The
asbestos or other resisting material V may be made in layers as shown, or it may
be molded into a solid mass. This arrangement presents certain advantages over
the one shown in Fig. 1, for the central hub G³, which is a good conductor of heat,
is dispensed with, and smaller space blocks substituted which are located at some
distance from the carbon pencil and have a small heat-carrying capacity.
Surrounding the lamp mechanism is a straight-sided cylindrical casing R shown
in section in Fig. 1, this casing fits very closely around the heads G³ and G4, 80
that the gas and heat have no direct passage through the lamp
Surrounding the lower part of the casing is a cornice Q which is rigidly attached
to the casing at its upper end, but at the lower end is open to permit the passage
of air through the lamp mechanism At a point above the dead air space, the
casing is provided with a series of holes R¹ communicating with the chamber
formed by the cornice, and air entering this chamber will pass upward through the
lamp as indicated by the arrows, and out at the space between the upper cornice S
and the top C, thus tending to cool the lamp
The sides of the frame A are made of tubes A¹, and within these tubes are
rods U which form a support for the lower globe-holder Secured to the under
side of the cross-piece U¹ which connects the rods U, is a stud U to which the
globe-holder is secured
In Fig. 2 are indioated the circuit connections; a, represent the mains of an
alternating-current system, G, G¹ the coils of the lamp, D, D¹ the upper and lower
carbons, F the reactance, and E³ the switch for opening and closing the circuit of
the lamp
Having now particularly described and ascertained the nature of our said in-
vention (as communicated to us from abroad), and in what manner the same is to
be performed, we declare that what we claim is:-
-
1. In an electric are lamp, the combination of an actuating magnet with parallel
supporting rods, upon which the magnet is free to move in a vertical direction
2 In an electric are lamp, the combination of the actuating magnets, parallel
supporting rods, upon which the magnet is free to move in a vertical direction,
and a spring for cushioning the movement of the magnet
3 In an electric arc lamp, the combination of a pair of actuating magnets
capable of vertical movement, parallel rods for supporting and maintaining the
magneta in proper relation, and coiled springs surrounding the rods for cushioning
the movement of the magnets
4. In an electric arc lamp, the combination of a pair of actuating magnets,
capable of a limited amount of vertical movement jointly or separately. vertically
extending rods for supporting the magnets, and maintaining them in parallel
relation, and springs surrounding the rods, and set under the magnets, so that
they are compressed when the magnets are energized
5 In an alternating-current arc lamp, the combination of a pair of solenoid
magneta, a movable U-shaped laminated core for the magnets, and a stationary
laminated core arranged to complete the magnetic circuit of the moving core
6 In an alternating-current are lamp, the combination of a pair of actuating
solenoid magnets, spring supports for the magnets, a U-shaped core movable
within the magnets, a clutch mechanism, a spring connection between the core
and the clutch, and a core which is supported by the lamp frame for completing
the magnetic circuit of the movable core
7 In an electric arc lamp, the combination of an actuating magnet, a two-part
core, the parts of which are movable with respect to each other a clutch mechan-
ism, a connection between one of the parts of the core and the clutch, and a com-
pensating support for the said core and clutch, which is so arranged that as the
power of the magnet increases its supporting effect on the core and clutch decreases.

page_text: In an electric aic lamp, the combination of an actuating magnet, a two-part
core, the parts of which are movable with respect to each other, and a compen-
sating support for one portion of the core, comprising an extension spring which
is supported by a fixed part of the lamp
9. The combination of a pair of actuating solenoid magnets, a core comprising
a stationary and movable part, the movable part being arranged to work within
the magnets, a compensating spring support for the movable part of the core,
so arranged that as the power of the magnet increases its supporting effect
decreases, and a dash-pot for checking the too rapid movement of the core
10 In an electric arc lamp, the combination of a tube surrounding the carbon
pencil, an actuating magnet and core therefor, a support secured to the tube, a
projection on the support to which the magnet core is secured, a second projection
or extension of the support and a compensating spring which is secured to the
Becond projection.
11. In an electric arc lamp, the combination of an actuating magnet, a spring
support therefor, a core for the magnet, a clutch mechanism, a spring connection
between the clutch and the core, and a compensating spring support connected to
the core and a stationary part of the lamp
12 In an alternating-current are lamp, the combination of a laminated iron
core, an energizing coil for the core and metal heads for the spools upon which
the coil is wound, the said heads being slotted at the point where they enter the
magnetic field of the core to prevent eddy currents
13 In an alternating-current aic lamp the combination of a laminated iron
core forming a magnetic circuit which is more or less closed, a pair of magnets for
energizing the core, spools upon which the coils are wound, and metal heads for
the spools which are split at the point where they enter the field induced by the
coils.
14. In an alternating-current arc lamp, the combination of a pair of energizing
solenoid magnets, a laminated iron core upon which the coils are placed, spools
upon which the coils are wound surrounding the cores, split metal heads for the
spools, and projections on the heads for supporting the coil
15 In an arc lamp. the combination of a casing which encloses the lamp
mechanism, a chamber located between the arc and the lamp mechanism to prevent
the heat and gas from the arc from passing upward through the lamp mechanism,
and a ventilating opening in the casing, which communicates with the external
air
16 In an arc lamp, the combination of a casing which encloses the lamp mech-
anism, a chamber located between the arc and the lamp mechanism to prevent
the heat and gas from the arc from passing upward through the lamp mechanism,
and ventilating openings in the casing which are situated above the chamber and
communicate with the external air
17 In an arc lamp, the combination of a casing which encloses the lamp mech-
anism, and a chamber containing a heat resisting material which is located
between the arc and the lamp mechanism to prevent the heat and gas from the
arc from passing upward through the lamp mechanism
18 In an arc lamp, the combination of a casing which encloses the lamp mech-
anism, a chamber containing a heat-resisting material which is located between
the arc and the lamp mechanism, to prevent the heat and gas from the arc from
passing upward through the lamp mechanism, and a ventilating opening in the
casing which communicates with the external nir
19 In an electric arc lamp, the combination of a casing which encloses the
lamp mechanism, a chamber located between the arc and the lamp mechanism
to prevent the heat and gas from the arc from passing upward through the lamp
mechanism, the said chamber being filled with sheets of asbestos.
20 In an electric are lamp, the combination of a casing surrounding the lamp
mechanism, a chamber between the arc and the lamp mechanism for preventing

page_text: the heat and gas from the arc from passing upward through the lamp mechanism,
and a removable bushing which surrounds the carbon and assists in preventing
the upward passage of gas and heated au
Dated this 9th day of June 1898
THE BRITISH THOMSON-HOUSTON CO, LTD,
A R. MONKS,
Director.
Alfred CLEMENTS,
Assistant Secretary