Improvements in Automatic Cut-outs for Electric Arc Lamps Worked in Series.
Year: 1887

page_text: Date of Application, 19th Apr., 1887
Complete Left, 9th Jan., 1888
Complete Accepted, 10th Feb., 1888
Improvements in Automatic Cut-outs for Electric Arc Lamps
Worked in Series.
We, EDWARD FREDERICK HERMANN HEINRICH LAUCKERT of Charlton in the
County of Kent Electrical Engineer, and HENRY WALTER KINGSTON of 1 Albion
Street Lewisham in the County of Kent, Electrician, do hereby declare the nature of
this invention to be as follows:-
This invention relates to cut-outs for a set of electric arc lamps worked in series, so
arranged that when any lamp becomes extinguished owing to the consumption or too
great separation of the carbons, that lamp is automatically cut out of the general
circuit, which is then completed through a resistance equivalent to that of the lamp
cut out. For this purpose each lamp is provided with a solenoid having a highly
resisting coil in a circuit which is a shunt or by-pass to the lamp circuit. The core of
this solenoid which is supported by an adjustable spring has connected to it a pair of
arms situated over cups containing mercury, these cups being connected to a by-pass
circuit in which there is a resistance equivalent to that of the lamp.
When owing to
extinction or other cause, the resistance of the lamp itself becomes excessive the
current passing through the solenoid coil increases in strength and further excites it
until the core, being attracted in opposition to the spring, moves in such a manner
as to immerse the arms in the mercury and so close the circuit through the resistance.
In order to ensure rapid and complete contact through the mercury, the solenoid core,
instead of working the contact arms directly, may by means of tappets act on a lever
provided with a tumbling weight, which, once its centre of gravity passes the vertical,
falls fully over making complete contact. Or the solenoid may have a second coil
forming part of the resistance circuit so that, as soon as the current begins to pass
through this circuit the power of the solenoid is increased and the arms are thus held
firmly in the mercury after contact is made. When by the approach of the carbons,
the resistance of the lamp circuit is reduced, lessening the current through the
solenoid coil, the spring overcomes the attraction on the core which moves, with-
drawing the arms from the mercury and thereby opening the resistance circuit.
Although we have described mercury contacts, which are convenient for apparatus of
this kind, obviously other contacts may be employed.
Dated this 19th day of April 1887
ABEL & IMRAY,
Agents for the Applicants.

page_text: We EDWARD FREDERICK HERMANN HEINRICH LAUCKERT of Charlton in the
County of Kent, Electrical Engineer and HENRY WALTER KINGSTON of 1 Albion
Street Lewisham in the County of Kent Electrician 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 cut outs for a set of electric are lamps worked in series so
arranged that when any lamp becomes extinguished owing to the consumption or too
great separation of the carbons, that lamp is automatically cut out of the general
circuit which is then completed through a resistance equivalent to that of the lamp
cut out.
For this purpose each lamp is provided with a solenoid having a highly resisting
coil in a circuit which is a shunt or by-pass to the lamp circuit. The core of this
solenoid which is supported by an adjustable spring, has connected to it a pair of arms
situated over cups containing mercury, these cups being connected to a by pass
circuit in which there is a resistance equivalent to that of the lamp.
When, owing to extinction or other cause, the resistance of the lamp itself becomes
excessive the current passing through the solenoid coil increases in strength and
further excites it until the core being attracted in opposition to the spring moves in
such a manner as to immerse the arms in the mercury and so close the circuit chrough
the compensating resistance. In order to ensure rapid and complete contact through
the mercury, the solenoid core, instead of working the contact arms directly may by
means of tappets act on a lever provided with a tumbling weight which once its
centre of gravity passes the vertical, falls fully over making complete contact. Or
the solenoid may have a second coil forming part of the resistance circuit so that,
as soon as the current begins to pass through this circuit, the power of the solenoid is
increased and the arms are thus held firmly in the mercury after contact is made.
When by the approach of the carbons the resistance of the lamp circuit is reduced
lessening the current through the solenoid coil, the spring overcomes the attraction on
the core which moves withdrawing the arms from the mercury and thereby opening
the compensating resistance circuit. Although we have described mercury contacts
which are convenient for apparatus of this kind, obviously other contacts may be
employed.
Fig. 1 of the accompanying drawings illustrates diagrammatically a cut out
according to this invention applied to each of a series of arc lamps L in the circuit of
a dynamo machine D. The terminals T T besides being connected in circuit through
the carbons and arc, are also connected by a shunt including a fine wire w of high
resistance being the shunt coil of a differential lamp and by another shunt including a
highly resisting coil of a solenoid S the core C of which is held up by an adjustal.le
spring. From the main lead at Z there is a conductor, including a resistance

page_text: equivalent to that of the lamp, to a mercury cup M over which is mounted a tumbler N
the arm of which is between two tappets on the stem of the core C.
When the lamp is extinguished the current goes from T to T¹ partly through w and
partly through the coil of S and the core is drawn down until its upper tappet
cants the tumbler N so that it makes contact with the mercury M whereupon the
current can go from Z through the by pass including the resistance R by M and
N to T.
When the lamp circuit is re-established very little of the current passes through the
coil of S and consequently the core C is raised by the spring and its lower tappet
acting on the tumbler N breaks its contact with the mercury and so opens the by pass
from Z to T1. According to the modified arrangement illustrated by Fig. II the
solenoid S besides the coil of high resistance connecting T to T1 has also in the line
from Z to the mercury M a coil on the solenoid acting as resistance along with R to
make up an equivalent for the resistance of the lamp. When owing to the extinction
of the lamp the core Cis drawn down as above described, the fork P on the stem of
the core dips into mercury at M and M' closing the by pass circuit from Z to T¹, but
as in this circuit the current passes through the second coil of S, the core C is more
forcibly drawn down, and is held down maintaining the by pass until the lamp circuit
is re-established.
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed we declare that what we claim is :-
As a cut out for each of a series of electric arc lamps a solenoid having a coil of
high resistance in a by pass to the lamp circuit and a core supported by a spring and
arranged to act ou contacts, whereby when the core is drawn down by increased
attraction of the solenoid resulting from extinction of the lamp a by pass circuit is
established including resistance equivalent to that of the lamp substantially as herein
described and illustrated by the drawings.
Dated this 9th day of January 1888