An Improved Automatic Cut-out or Short Circuiting Device for Electric Arc Lamps.
Year: 1897

page_text: Date of Application, 15th Nov., 1897-Accepted, 19th Feb., 1898
COMPLETE SPECIFICATION.
An Improved Automatic Cut-out or Short Circuiting Device for
Electric Arc Lamps.
We, RICHARD WILHELM LUDWIG HOLSTEN, and the ELEKTRISCHE BOGEN-
LAMPENFABRIK NAECK & HOLSTEN GESELLSCHAFT MIT BESCHRÄNKTER HAFTUNG,
both of Stralsund, in the Empire of Germany, Engineer and Manufacturers
respectively, 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 automatic cut-out or short circuiting device for
elcetric arc lamps adapted to avoid the simultaneous extinction of one or more arc
lamps connected in series with the lamp carrying the device when the are in the
latter lamp is from any cause interrupted.
The object of the invention is shown diagrammatically in the accompanying
drawing:
The electro-magnet e which forms the arc light and regulates it and is inserted
in the shunt circuit of the lamp acts on an armature f. The latter is conductingly
connected with the frame of the lamp attached to the negative pole and carries on
its part, which is prolonged above the magnet e, a platinum plate g¹. A platinum
pin g mounted in the iron core of an electro-magnet d stands opposite the plate g¹.
One end of the coil of the electro-magnet d is also attached to the iron core.
other end of this coil leads to a terminal insulated like the other terminal a from
the frame of the lamp.
The
On this terminal and on the positive pole of the main conductor a resistance h
is inserted. This is so equalised that, on the passage of the current through it,
there results an electromotive force of 6 to 8 volts more than when the lamp is
burning.
The mode of operation of the apparatus is as follows:-
When the lamp is burning normally, the electro-magnet e forming the arc light
and regulating it attracts the armature f. Its attraction is however so limited
that at a normal working pressure of about 38 volts there still remains between
the armature and the magnet pole a space of a few millimetres. The armature is
therefore still capable of making a further movement to that extent.
The moment the carbons no longer approach one another and the arc light
ceases from any cause, the pressure at the terminals of the arc lamp rises of course
considerably, the armature therefore completes its movement until the platinum
plate gl mounted thereon encounters the platinum pin g and affords a new course
to the current, so that the other are lamps of the series connected are not affected.
The current takes the following course: It passes from the positive pole through
the resistance h, terminal b, magnet coil d, magnet core, platinum ping and
platinum plate g₁ of the armature f back to the negative pole or terminal c.
The device which effects the subsequent adjustment of the carbons, for instance
the automatic interrupter, continues to work in the meantime as the pressure at
the terminals of the lamp is about 6-8 volts higher than the burning pressure.

page_text: The contact of the two platinum parts g g¹ is as may be seen a very certain and
good one. It is in fact only started or initiated by the greater attraction of the
armature f by the electro-magnet e. It is completed and attained in a hitherto
unattainable manner only by the electro-magnet d being strongly excited in con-
sequence of the first short circuiting current shock, and by the armature f being
thus extremely strongly attracted by it. The two platinum contact pieces g g are
thereby firmly pressed one against the other. If the breakage of the arc light is
only a temporary one, and the constantly working automatic interrupter again
pushes the carbons together, the coil d is rendered currentless by the short circuit
of the carbons, and the armature f is released by the electro-magnet d whereby
the short circuit is broken and the are light again re-established.
If the carbons are however burnt out so that the arc light cannot be re-
established, the rattling or buzzing of the automatic interrupter draws attention
from a considerable distance to the fact that new carbons must be inserted. These
can of course be inserted without switching off the lamp series.
By the use of a solenoid instead of the electro-magnet the short circuiting device
is also applicable for alternating current.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
An automatic cut-out or short circuiting device for electric arc lamps, char-
acterised by the arrangement on an armature and on a core of an electric magnet
traversed by the short circuiting current, of platinum parts adapted to establish a
contact, the current aroused by the short circuiting exciting the said magnet with
the object of reliably securing the contact of the two platinum parts and on the
electro-magnets becoming again currentless removing the contact or rather the
short-circuit in the arc lamp, substantially as herein before described.
Dated this 13th day of November 1897.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicants.