IMPROVEMENTS IN APPARATUS FOR SHORT CIRCUITING INCANDESCENCE LAMPS ARRANGED IN SERIES
Year: 1884

page_text: COMPLETE SPECIFICATION.
I, CHARLES DENTON ABEL of N° 28 Southampton Buildings, Chancery Lane,
in the County of Middlesex, Consulting Engineer and Patent Agont, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN APPARATUS FOR
SHORT CIRCUITING INCANDESCENCE LAMPS ARRANGED IN SERIES" and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :—
In arranging incandescence lamps in series on a conductor it is necessary to
provide means by which, when one of the lamps ceases to act, the current is caused
automatically to pass uninterruptedly through the other lamps so that their action
may not be interfered with, the lamps being thus rendered independent of ouch
other. This is effected according to the present Invention by providing each lamp
with a bye-pass or shunt circuit of high resistance through which a small portion of
the current is consequently always passing when the lamp is in action, but instead
of causing the entire current to pass through the shunt circuit to the other lamps
when the lamp ceases to act which would be objectionable on various grounds, a
small increase of the current passing through the same is made to effect the closing
of the contact arrangement of a second shunt circuit of low resistance through
which the current then passes.
Fig. 1 of the accompanying Drawings shews a diagram of one arrangement for
this purpose. The shunt circuit of high resistance constitutes a solenoid or
electromagnet E, which, when only excited by the quantity of the current passing
through it, when the lamp is in action, is not strong enough to actuate the hook
shaped armature G which holds the contact lever A of the second shunt circuit of
low resistance out of contact but when in consequence of the decrease or
interruption of the current passing through the carbon filament the current
through E is increased, the hook shaped armature G is attracted and in thereby
releasing the contact lover A allows this to be acted upon by a spring F so as to
close the contact of the shunt circuit of low resistance through which the current
will now pass on to the other lamps only a very small portion of the same
continuing to pass through E.
Figs. 4 to 7 of the Drawings shew one arrangement for carrying out this modo
of action and Fig. 8 shews an incandescence lamp constructed according to this
Invention mounted on pivots between the arms g g of a candelabrum. The arms
g¹ contain the conducting wires of the circuit of which one is shewn at d and
which are electrically connected to the conducting pivots a and 2 of the lamp. If

page_text: the branches g g' are of conducting metal, they are insulated by a cap i from the
conducting sockets of the trunnions a and %. The lamp is connected in a readily
removeable manner to the lamp holder. This consists of a wood block on which
are fixed two segmental spring contact plates p¹ p³ which by a partial turn of the
holder are made to pass over and hold two brass plates o of that are connected to
the conductors of the lamp. The plates oo' are securely locked in position by
means of spring studs bb' in the holder that enter grooves in the plates o o¹ and
thus prevent them from shaking loose.
To the metal casing of the holder is connected, by means of screws ¹ the
metal casing continuing the before described shunt mechanism which is
electrically connected to the spring contact plates pl p² by means of the conducting
wires c c' fixed to the latter and shewn in Figs. 4, 6 and 7.
Assuming the electrical current to enter the lamp through the one arm g and
trunnion a, it will pass as follows:-
The set screws 88 that secure the plates pl p' and also the wires c c² are screwed
into extensions of the pivots a and 2, being thus in conducting connection
therewith. The current consequently passes through the pivot a and screw a at
the head of which it divides into two, one part going through plates p² and o into
the lamp, while the other part passes through wire c, as indicated in Figs. 4 and 6
to screw screwed into.a brass piece, to which the one end of a small wire coil is
- secured by a screw 12, which coil leads the shunt current at m into the coil s p of
the electromagnet E. of the shunt mechanism. The coil sp consists of a
considerable length of thin wire, so that only a small part of the current entering a
will pass through it, the greater portion passing through the carbon filament of the
lamp when this is in action. The said weak current leaves the coil & p at n and
passes through screws and k fixed in one and the same brass block, and into
the wire cas shewn-at-Fig-4, c'-being-connected-to the second contact_plate_pª_so_
that the shunt current here meets the main current as this leaves the lamp. The
combined current then passes through screw 8 to the trunnion and thence
through the second arm g³ to the next lamp or back to the generator.
If now the resistance of the conductor formed mainly by the carbon filiament is
considerably increased or if this conductor be broken, the shunt current will
increase in strength until the electromagnet has sufficient power to attract the
armature G in opposition to the action of the spring f, whereby the blade spring F
(Fig. 6) which was held back by a notch in the armature will be allowed to spring
forward and make contact with the screw r, and this contact will remain until a
new lamp is to be introduced. The button e attached to the spring F is then
pushed back so as to bring the spring into its backward position again, and the
contact with being broken, the current will pass through the carbon filament of
the lamp again.
Instead of short circuiting the current of the lamp as described, it may be led
through a supplemental lamp, as shewn in the diagram at Fig. 2. The supple-
mentary lamp must however in that case be provided with a short circuiting
arrangement.
By the above described arrangement of shunt circuit not only is the continuity
of the current on the extinguishing of the lamp insured, but also, this is effected
without any momentary extinguishing of the other lamps, and even without
material fluctuation of the light thereof. The degree to which this result is
obtained depends mainly upon the choice of the resistance employed in the main
circuit and in the individual lamps, and their shunt circuits.
The smaller the resistance of the shunt circuit is in proportion to that of the
entire circuit the smaller will be the fluctuations produced by the momentary
introduction of the shunt circuit into the main circuit, in the strength of the main
current and in the light of the lamps.
In order to reduce the fluctuations in the light as much as possible on the-
extinguishing of one of the lamps, it is very advisable to arrange the current
generator in such manner that the strength of the current shall always remain.

page_text: constant independently within certain limits of the variation of the resistances in
the circuit. It is of course desirable to make the shunt apparatus as compact as
possible so as not to make the lamp holder too bulky. On the other hand, as
before stated, it is also of advantage to make the resistance of the shunt circuit as
Bmall as practicable which would necessitate the use of a comparitively thick wire
and would consequently render the arrangement comparatively bulky.
In order to satisfy both the required conditions an arrangement is employed in
certain cases in which the shunt circuit is made of thin wire so as to provide the
requisite resistance, but this shunt circuit is only brought into action when the
lamp is extinguished, so that its resistance is not permanently interpolated in
the circuit. This is effected, as shewn diagrammatically at Fig. 3 by the
employment of a small electromagnet x excited by the main current so as to hold
an armature y, (which is also connected to the circuit), in the position shewn. On
the extinguishing of the lamp, the current will momentarily cease. The armature y
will then be drawn down by a smaller spring so as to make contact with the shunt
circuit E, which in its turn will attract the armaturo G and so liberate the contact
lever A so as to short circuit the lamp as before. The current in the main circuit
being thus re-established, the electromagnet x will again attract the armature y
thereby cutting out tho shunt circuit E again.
All the lamps on the circuit being provided with an electromagnet such as x,
these will all release their armatures when one lamp is extinguished, but only the
shunt circuit of the latter will effect a short circuiting.
Having now particularly described and ascertained the nature of the said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
1. In short circuiting apparatus for incandesconce lamps arranged in series.
The use of a shunt circuit or by-pass of high resistanco so arranged in combination
with a short circuiting contact that when the lamp is extinguished, the shunt
current increases sufficiently to effect the releasing of the said contact so as to short
circuit the lamp, the shunt current being at other times too feeble to effect such
release, substantially as herein described.
2. The use of a shunt circuit of high resistance in the form of an electromagnet
or solenoid operating in combination with a hook shaped armature that holds a
short circuiting contact spring out of contact, so that on the extinguishing of the
lamp the shunt current increases sufficiently to attract the armature and release
the contact spring so as to short circuit the lamp.
3. In combination with the short circuiting mechanism such as is referred to in
the preceding claims, the use of an electromagnet excited by the current of the
main circuit, which electromagnet holds a contact armaturo so as to cut out the
shunt circuit while the lamp is in action, but which releases the armature so as to
put the shunt circuit in action when on the extinguishing of the lamp the main
current momentarily ceases, substantially as herein described.
4. The use in combination with short circuiting mechanism such as is referred
to in the preceding claims of one or more supplemental lamps so that when the
primary lamp is extinguished, the said short circuiting mechanism brings a
supplemental lamp into action substantially as herein described.
Dated this 95th do of Anouch 1881
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.