An Improvement in Electrical Arc Lamps.
Year: 1894

page_text: Date of Application, 20th Mar., 1894
Complete Specification Left, 17th Aug., 1894-Accepted, 22nd Sept., 1894
PROVISIONAL SPECIFICATION.
An Improvement in Electrical Arc Lamps.
WILLIAM HARDING LAUDER Photographer 33 Blessington Street Dublin
Ireland do hereby declare the nature of this invention to be as fellows:-
My invention relates to an adjustment for arc lamps of a certain type which
ensures them striking their arcs or separating the carbons when the current is
switched on with promptitude and at the same time reduces their range or variation.
The types referred to are those whose striking and feeding mechanism is controlled
by two separate solenoids, a series the core of which operates the feed mechanism
and strikes the arc or separates the carbons, the other a shunt solenoid (shunt
across arc) the core of which operates the feed and striking mechanism against the
pull of the series core when the resistance of the arc gets to the normal and brings
the carbons closer together. The adjustment may consist of a piece of soft iron
so arranged in the shunt solenoid as to act attractively on the shunt core and
intensify the pull of the shunt against the series core when the resistance of the are
arrives at its normal. This piece of soft iron has an adjusting screw allowing it to
be approached more closely or withdrawn further from shunt core.
The soft iron adjustment might if necessary be wound with a portion of the wire
forming the shunt and in series with shunt solenoid, or a permanent magnet might
be used with its poles so placed in respect to the shunt windings as to have its
attractive powers intensified when the resistance of the arc increases by the carbons
burning away.
19th March 1894.
WILLIAM HARDING LAUDER.
COMPLETE SPECIFICATION.
An Improvement in Electrical Arc Lamps.
I, WILLIAM Harding Lauder, of 33 Blessington Street, Dublin, Ireland,
Photographer, 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 an adjustment for arc lamps of a certain type, which
nsures them striking their arcs or separating the carbons when the current is
ewitched on with promptitude, and at the same time reduces their range or variation.
The type referred to viz. that in which the striking and feeding mechanism is
controlled by two separate solenoids; one a solenoid coupled up in series with the
lamp, the core of which operates the feed mechanism and strikes the arc or separates
the carbons; the other a solenoid, connected up in a shunt circuit across arc, the
core of which operates the feed and striking mechanism against the pull of the core
of the series-solenoid, when the resistance of the arc arrives at the normal, and
brings the carbons closer together.
My invention consists of an adjustable influencing device adapted to operate
upon the core of the shunt-solenoid, under certain circumstances, or conditions of
the current, working the lamp.

page_text: This adjustment may consist of a piece of soft iron, so arranged in the shunt
solenoid as to act attractively on the shunt-core, and intensify the pull of the shunt-
solenoid on its core against the series-core, when the resistance of the arc arrives at
its normal. This piece of soft iron has an adjusting screw or other equivalent
device, allowing it to be approached more closely to or withdrawn from the shunt-
core.
"
This soft iron adjustment might, if necessary, be wound with a portion of the
wire forming the shunt, and be coupled up in series with shunt-solenoid, or a
permanent magnet might be used with its poles so placed in respect to the shunt
windings, as to have its attractive powers intensified when the resistance of the arc
increases by the carbons burning away.
In order that my invention may be the better understood, I will now proceed to
describe the same in relation to the accompanying drawings, reference being had to
the letters and figures marked thereon.
Figure 1 is a view of an electric arc lamp with my regulating device attached
thereto.
.
Figure 2 is an enlarged detail view of the same.
This invention is shown in Figure 1, by way of example, in connection with a
lamp, made in accordance with the Specification of Letters Patent granted to me
under No. 933 of 1893.
It will be noticed that the lamp is of the differential type, the clutch mechanism
being controlled by two solenoids, one f and being a series-solenoid in the main
circuit, its primary duty being to separate the carbons and strike the arc; the
other a being a solenoid in a shunt-circuit of high resistance (the shunt circuit being
across the arc) which operates against the pull of the series-solenoid, when the arc
arrives at its normal, and brings the carbons closer together, preventing the arc
becoming unduly long.
The cores 6 and i of these solenoids a and ƒ respectively are pivotably attached to
the clutch-traversing-lever j and by operating it controls the relative positions of the
carbons of the lamp.
The invention is shown in Figure 1, to consist of a piece of soft iron c, arranged
in the shunt-solenoid with an adjusting screw e, capable of approaching it closer to,
or moving it further away from the core b. The amount of range of downward
movement in this screw is so arranged that the piece of soft iron c cannot, when it
is in its lowest position, touch the core when the latter is in its highest position
in the solenoid.
The manner in which this adjustable regulator operates is as follows:--- When
the current is switched on to the lamp, the series solenoid f is powerfully magnetised,
and attracts its core i upwards, raising the traversing lever j, and clutch mechanism,
stopping only when it has separated the carbons and established an arc.
The core b
of the shunt-solenoid being pivotted to the other end of the traversing lever j, the
core b is drawn downwards out of the shunt-solenoid, as the core i moves upwards
in the series-solenoid. The solenoid a does not offer much opposition to the down-
ward movement of its core b when the arc is being struck; being energised by a
shunt coil of high resistance, it does not arrive at its maximum power until the arc
has burned to its normal resistance; when this occurs the solenoid a begins to
operate its core-b in opposition to the pull of the series core i, making it gradually
lower its position, and bringing with it the clutch gear and carbou rod. The soft
iron core c
being magnetized as well as the core b, the attractive power of the core c
for the core increases out of direct proportion to the distance that the core b
moves upward in the solenoid a, and only arrives at its maximum power at the
moment when the lamp is feeding, and the core i has become more powerful, in
consequence of being relieved of the clutch load at the moment of feeding.
By these means I provide an accumulative power in the shunt-solenoid which does
not operate in the first instance against the striking of the arc, but which gradually
gathers power, arriving at its maximum eflect at the moment when the series-core i
becomes more powerful, in consequence of partially losing the load it had been

page_text: previously carrying. The soft iron e might if desired, be wound with som” of the
wire forming the shunt circuit, and in series with it; or it might be a permanent
magnet, with its poles so arranged in relation to the shunt winding, as to have its
attractive powers increased.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1st. In an electric arc lamp, in which the carbons are controlled by a series-
solenoid working in conjunction with a shunt-solenoid, an adjusting device upon the
shunt-solenoid, consisting of an adjustably fixed magnetic core, adapted to act upon
the movable core, substantially as described.
2nd. In an adjusting device as claimed in Claim 1, a magnetic core, mounted
upon a screw or other equivalent device, adapted to adjust the position of the said
fixed magnetic core, in combination with the main core of the shunt-solenoid.
3rd. An adjusting device for electric arc lamps constructed and arranged as
described and illustrated in the accompanying drawings.
Dated this 17th day of August 1894
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.