IMPROVEMENTS IN ELECTRICL LAMPS
Year: 1881

page_text: LETTERS PATENT to Legh Sylvester Powell of Notting Hill in the County
of Middlesex for an Invention of "IMPROVEMENTS IN ELECTRICL LAMPS "
A communication from abroad by Jean Marie Anatole Gérard-Lescuyer, of
Paris in the Republic of France Engineer.
PROVISIONAL SPECIFICATION left by the said Legh Sylvester Powell at
the Office of the Commissioners of Patents on the 24th December 1881.
LEGH SYLVESTER POWELL of Notting Hill in the County of Middlesex
"IMPROVEMENTS IN ELECTRIC LAMPS." A communication from abroad by Jean
Mario Anatole Gérard-Lescuyer of Paris in the Republic of France Engineer
This Invention relates to electric lamps and it consists in certain improvements
in the construction and arrangement of the apparatus for automatically operating
and generating the feed of the carbons employed to produce the voltaic arc as
hereinafter described.
In carrying out this Invention as applied to a lamp worked by alternate currents,
for example the improved apparatus is constructed with a body or frame, formed
by say, two long vertical side rods and three horizontal cross bars or plates. An
electro-magnet provided with a coil of fine wire forming a shunt or derived circuit,
is connected with the lamp circuit by suitable binding screws and arranged between
the vertical rods. A copper tube, forming a pump cylinder is provided in the
centre of this electro magnet and the upper carbon holder of the lamp is connected
with a piston working in the said cylinder which is enclosed in a sheath or tube of
soft iron constituting the acting core of the coil. At the upper extremity of the
tube there is provided a suitable valve for regulating the admission of air to the
space above the piston so as to control the descent of the upper carbon holder.
The lower carbon holder is carried by a movable support or frame formed by the
lower extremities of the vertical rods and the lower horizontal bar. The vertical
rods slide in insulating sleeves carried by the upper and middle horizontal bars and
are connected to the lower bar by nuts and screws. Helical springs, the tension of
which is adjusted by suitable nuts on the vertical rods serve to connect the latter
to the upper bar and counterbalance the weight of the rods and of the lower carbon*
holder. The separation of the carbons for establishing the arc is effected by means
of an iron armature connected with the two rods and situate underneath the lower
extremity or pole of the electro magnet and the descent of the upper carbon is
arrested when required by a brake or device worked by the upper extremity or

page_text: pole of the same magnet. This brake is constructed with two short vertical rods
connected together at their upper extremities by an iron armature facing the upper
extremity of the electro magnet and two bent claws oscillating upon stationary
pivots are jointed to the lower extremities of these rods. That part of the claws
which faces the carbon holder terminates in a sector provided with screws or pro-
jections capable of clasping and supporting the carbon holder and two helical springs
connected to the upper horizontal bar serve to support and counter balance the
weight of the short rods which are also insulated from the body of the lamp.
One of the two binding screws herein before referred to is connected with the
upper carbon by the body of the magnet and suitable brushes or contact makers,
the other binding screw being in connection with the lower carbon through the
vertical rods and the lower carbon holder.
A suitable screen is employed to protect the working parts from the heat pro-
duced by the arc and the hook or ring is attached to the upper horizontal bar for
the purpose of suspending the lamp.
This apparatus operates in the manner next hereinafter described. Before
lighting the lamp the carbons are separated so that the current being unable to
pass along the carbons is entirely diverted into the shunt or coil of the electro
magnet which thus becomes excited and attracts the two armatures herein before
described. The attraction exerted on the upper armature has the effect of drawing
down the short vertical rods and thus opens the claws causing them to release the
upper carbon holder which thereupon slips down very slowly, its descent being
retarded by the partial vacuum produced behind the piston. The rate at which the
carbon descends may thus be controlled by adjusting the valve which admits air to
the pump cylinder.
The lower armature is also attracted by the electro-magnet at the same time
as the upper armature in such a manner as to draw up the flame connected with
the lower carbon holder. When the carbons are thus brought into contact the
current passes through them almost exclusively so that the electro-magnet is
demagnetised. The armature connected with the claws is then raised by the
helical springs supporting the short rods and the claws again clasp the upper carbon
holder whilst at the same time the lower carbon holder is also released and allowed
to drop by its own weight for a distance regulated by suitable nuts or stops on the
long vertical rods, thus establishing the arc, then the resistance of the arc
becomes excessive, the power of the current in the coil of the electro magnet is
increased whereupon the armatures are again attracted and the carbons are brought
together as herein before described.
According to another modification of the lamp in which either alternate or
continuous currents may be employed two coils and two electro magnets are
provided, one wire being composed of fine wire forming a shunt on the main
circuit and the other being composed of thicker wire forming part of the said
circuit. The armature which serves to effect the separation of the carbons is
arranged above the lower coil but in other respects the lamp resembles the one
hereinbefore described.
.
On commencing to work a lamp constructed according to this modification, the
carbons may be either in contact or separated. When they are separated for
example, the current passes exclusively through the shunt or branch circuit so that
the electro magnet enclosed in the upper coil becomes excited and attracts the
upper armature causing the claws to release the upper carbon holder which
immediately commences to descend until contact is established between the points
of the carbons whereupon the current passes along the carbons and is entirely
diverted from the shunt to the lower coil. The core of this coil then becomes
powerfully magnetised and pulls down the lower armature thereby lowering the
frame connected with the lower carbon holder to the required extent and thus
establishes the arc, whilst at the same time the core of the upper coil is demag-
netized, releases the upper armature and allows the claws to grip the upper carbon
holder and arrest its descent.

page_text: The descent of the upper carbon may also be controlled and regulated by the
action of air alone by means of a valve, arranged as hereinafter described. For
this purpose, the lamp is constructed with a fixed or rigid frame as is provided with
two coils one coil of fine wire forming a branch or shunt circuit and the other coil
being of thicker wire arranged in the circuit of the lamp. A copper tube is passed
through both coils and encloses another copper tube fitted to slide within the first
or outer tube. The downward motion of the inner tube is limited by a flange at
its upper extremity and an armature is attached to the lower extremity of this
tube and also to a pair of springs which serve to counterbalance the weight of the
sliding tube and of the upper carbon holder to which it is attached. That part of
the upper tubes which is surrounded by the lower coil is enclosed in an iron
sheath or tube which constitutes the acting core of this coil. The upper coil thus
acts as a solenoid and the lower coil as an electro magnet.
The valve for controlling the descent of the upper carbon holder is capable of
sliding within the inner tube and consists of a piston valve constructed in two
parts connected together by a hollow screw and provided with three leather
washers or packing which prevents the air from passing between the sides of the
valve and of the tube.
The lower part of a hollow plug in the upper extremity of the inner tube serves
to limit the upward motion of the piston valve which is suspended by a spring
attached to a screw passed through the plug and secured and adjusted by a nut
on the outside.
The upper part of the piston valve is perforated with a radial hole communi-
cating through the hollow screw with the space above a piston which is connected
with the upper carbon as in the case of the lamp firstly lierein before described and
the inner tube is also provided with an oblique slit or aperture in its side near its
upper extremity.
When the piston valve is in its highest position the external air cannot enter
the space above the piston connected with the carbon holder which consequently
remains stationary.
The piston rod being of iron is attracted when the upper coil which surrounds it
is excited in consequence of interruption or excessive resistance to the passage of
the current through the carbons and thus brings an annular recess in the side of
the upper part of the said valve opposite the aperture or slit in the side of the
tube and allows air to pass through the radial hole and the hollow screw in the
valve to the space above the piston connected with the upper carbon.
Air being thus admitted this piston descends until the carbons come in contact
whereupon the greater part of the current passes along the wire of the lower coil
the attraction exercised by the upper coil upon the piston valve is at the same
time considerably weakened allowing the said valve to be drawn up by the action
of the spring from which it is suspended and again cuts off the supply of air so as
to arrest the descent of the upper carbon The electro magnet in the lower coil
becomes at the same time powerfully excited and attracts its armature so as to
draw up the inner tube together with the piston and the carbon holder and thus
separates the Carbons to the extent necessary to establish the arc.
The introduction of air to the space above the piston of the Carbon holder may
also be effected by means of a loose iron piston suspended by a spring in the
interior of the coil on the shunt circuit which piston when drawn down by the
action of the said coil opens a suitable valve and admits air as required.
It is evident that similar results can be obtained by causing the piston connected
with the Carbon to compress air in lieu of allowing it to exhaust or draw in air as
in the arrangements hereinbefore described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Legh Sylvester Powell in the Great Seal Patent Office on the
23rd June 1882.
LEGH SYLVESTER POWELL of Notting Hill in the County of Middlesex
"IMPROVEMENTS IN ELECTRIC LAMPS " A communication from abroad by Jean
Marie Anatole Gérard-Lescuyer of Paris in the Republic of France Engineer
This Invention relates to electric lamps and it consists in certain improvements
in the construction and arrangement with the apparatus for automatically operating
and regulating the feed of the Carbons employed to produce the voltaic are as
hereinafter described.
I will describe the Invention with reference to the accompanying Drawings.
Figures 1. 2. 3. and 4 represent a lamp worked by alternate currents to which the
Invention is applied the said Figures representing respectively a vertical section a
side elevation a plan and a horizontal section of the said lamp.
The body or frame of the lamp is formed by say two vertical side rods A and 1
horizontal cross bars or plates B. C. 1). An electro inagnet provided with a coil E.
of fine wire forming a shunt or derived circuit connected with the lamp circuit by
binding screws L L is arranged between the vertical rods A
A copper tube F forming a pump cylinder is provided in the centre of this
electro magnet.coil-and-the-upper-carbon-holder-G-of-the-lamp-is-connected-with-a-
piston I working in the said pump cylinder F which is enclosed in a sheath or
tube H of soft iron constituting the acting core of the coil E of the electro magnet
At the upper extremity of the tube F there is provided a suitable valve for
regulating the admission of air to the space in the tube above the piston I so as to
control the descent of the upper carbon holder G The lower carbon holder is carried
by a moveable support or frame formed by the lower extremities of the vertical
rods A and the lower horizontal bar D The vertical rods A pass through insulating
sleeves carried by the upper and middle horizontal bars B. C. and are connected to
the lower bar D by nuts and screws.
Helical springs P the tension of which is adjusted by nuts Q Q on the vertical
rods A serve to sustain the said rods in the upper bar and counterbalance the weight
of the said rods and of the lower carbon holder
The separation of the carbons for establishing the arc is effected by means of an
iron armature 0 (broken away in figure 2) connected with the two rods and
situate underneath the lower extremity or pole of the electro magnet E and the
descent of the upper carbon is arrested when required by a brake or device worked
by the upper extremity or pole of the same magnet. This brake consists of two
vertical rods S connected together at their upper extremities by an iron armature T
facing the upper extremity of the electro magnet E Two bent claws U capable
of oscillating upon stationary pivots V are jointed to the lower extremities of theso
rods S That part of the claws which faces the upper carbon holder terminates in
a sector provided with two screws or projections (as shewn clearly in Figure 4)
capable of clasping and supporting the carbon holder and two helical springs W
connected with adjusting screws on the rods S and to the upper bar B serve to
support and counterbalance the weight of the rods S and support the brake U V
which is also insulated from the body of the lamp
One of the two binding screws L herein before referred to is connected with the
upper carbon holder by the body of the magnet and suitable brushes or contact
makers the other binding screw L being in connection with the lower carbon
through the vertical rods and the lower carbon holder D.

page_text: A disc or screen Y is employed to protect the working parts from the heat
produced by the arc and a hook or ring Z is attached to the upper horizontal bar
for the purpose of suspending the lamp.
This apparatus operates in the manner next hereinafter described Before lighting
the lamp the carbons are separated so that the current being unable to pass along
the carbons is entirely diverted into the shunt or coil of the electro magnet which
thus becomes excited and attracts the two armatures O and T The attraction
exerted on the upper armature T has the effect of drawing down the short vertical
rods S and thus opens the claws U causing them to release the upper carbon holder
which thereupon slips down very slowly its descent being retarded by the partial
vacuum produced behind the piston I.
The rate at which the carbon descends may thus be controlled by adjusting by
means of the valve the rate at which air is allowed to pass into the tube F abovo
the said piston I.
The lower armature O is also attracted by the electro magnet at the same time
that the upper armature is attracted and in such a manner as to draw up the
rods A connected with the lower carbon holder D When the carbons are brought
into contact the current passes through them almost exclusively so that the electro
magnet E is demagnetised The armature T connected by the rods S with the
claws of the brake is then raised by the helical springs W around the said rods and
the claws U again clasp the upper carbon holder whilst at the same time the lower
carbon holder is also released and allowed to drop by its own weight for a distance
regulated by the nuts or stops R on the rods A thus establishing the arc
When
the resistance at the arc becoines excessive the power of the current in the coil of
the electro magnet E is increased whereupon the armatures are again attracted
and the carbons are brought together as hereinbefore described.
Figures 5 and 6 illustrate in elevations taken at right angles to each other another
modification of the lamp according to this Invention in which either alternate or
continuous currents may be employed According to this modification two coils
and two electro magnets A and B are provided the coil A being composed of fine
wire forming a shunt on the main circuit and the other coil B being composed of
thicker wire forming part of the said circuit The armature O' which serves to
effect the separation of the carbons is arranged above the lower coil B but in other
respects the lamp resembles the one herein before described.
On commencing to work a lamp constructed according to this modification the
carbons may be either in contact or separated When they are separated for
example the current passes exclusively through the shunt formed by the wire of
the coil A so that the electro magnet enclosed in the said coil A becomes excited
and attracts the upper armature T causing the claws of the brake (similar to that
described with reference to figures 1 to 4) to release the upper carbon holder
which immediately commences to descend until contact is established between the
points of the carbons whereupon the current passes along the carbons and is
entirely diverted from the shunt A to the lower coil B The core of this coil B
then becomes powerfully magnetized, and pulls down the lower armature O' thereby
lowering the frame connected with the lower carbon holder to the required extent
extent and thus establishes the arc whilst at the same time the core of the upper
coil A, is demagnetised and therefore releases the upper armature T and allows the
rods connected therewith to rise and consequently cause the claws to grip the
upper carbon holder and arrest its descent.
The descent of the upper carbon may also be controlled and regulated by the
action of air alone by means of the arrangement shown in Figure 7, the descent of
the said carbon being controlled by means of a valve arranged as hereinafter
described.
For this purpose the lamp is constructed with a fixed or rigid frame A B C D
and is provided with two coils one coil E of fine wire forming a branch.or shunt
circuit and the other coil F being of thicker wire arranged in the circuit of the
lamp. A Copper tube G is passed through both of the coils E and F and encloses

page_text: another copper tube H fitted to slide within the first or outer tube G. The down-
ward motion of the inner tube H is limited by a flange 11 at its upper extremity
and an armature L is attached to the lower extremity of this tube H and also to
a pair of springs K which serve to counterbalance the weight of the sliding tube H
and of the upper carbon holder to which it is attached.
That part of the copper tubes which is surrounded by the lower coil F is
enclosed in an iron sheath or tube which constitutes the acting core of this coil.
The upper coil E thus acts as a solenoid and the lower coil F as a hollow electro-
magnet.
The valve M for controlling the descent of the upper carbon holder is shewn in
detail in figure drawn to an enlarged scale.
This valve consists of a piston constructed in two parts M M¹ connected together
by a hollow screw m the said parts being provided with three leather washers
forming packing rings m² which prevent the air from passing between the sides
of the Valve and of the tube H. The lower part of a hollow plug h in the upper
extremity of the inner tube H serves to limit the upward motion of the piston
valve M which is supported by a spring e attached to a screw f passed through
the plug h and secured and adjusted by a nut 7 on the outside.
In the upper part of the piston valve M is a radial hole i communicating through
the hole in the hollow screw m with the space between the valve M and the
piston I which is connected with the upper carbon as in the case of the lamp firstly
hereinbefore described and the inner tube H is provided with an oblique slit or
aperture 2 in its side near its upper extremity.
-When-the-piston-valve-is-in-its-highest-position as shewn in Figure 8 the
external air cannot enter the space above the piston I connected with the carbon
holder which carbon holder consequently remains stationary.
The piston valve M being of iron is attracted when the upper coil which
surrounds it is excited in consequence of interruption or excessive resistance to the
passage of the current through the carbons and thus brings the annular recess i in
the side of the upper part of the said valve opposite the aperture or slit h² in the
side of the tube H and allows air to pass through the said radial hole i and the
hollow screw m to the space above the piston 1 connected with the upper carbon.
Air being thus admitted this piston I descends until the carbons come in contact
whereupon the greater part of the current passes along the wire of the lower
coil F The attraction exercised by the upper coil E upon the piston valve M is
at the same time considerably weakened allowing the said valve M to be drawn
up by the spring e and the said valve again cuts off the supply of air so as to
arrest the descent of the upper carbon. The electro magnet in the lower coil F
becomes at the same time powerfully excited and attracts its armature so as to
draw up the inner tube H together with the piston I and the upper carbon holder
and thus separates the carbon to the extent necessary to establish the arc.
Figure 9 illustrates another mode of regulating In this case the introduction
of air to the space above the piston of the Carbon holder may also be effected by
means of a loose iron piston M supported by a spring e in the interior of the coil E
of the shunt circuit which piston At when drawn down by the action of the said
coil opens a valve m and admits air as required.
It is evident that similar results may be obtained by causing the piston connected
with the Carbon to compress air in lieu of allowing it to exhaust or draw in air as
in the arrangements hereinbefore described.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is:-
First; The general arrangement or combination of parts constituting the
Electric Lamp substantially as herein before described and illustrated in figures 1
to 4 of the accompanying Drawings.

page_text: Second-The arrangement of brakes" for use with Electric Lamps substantially
as hereinbefore described with reference to figures 1 to 6 of the accompanying
drawings.
Third. The means for producing automatically the regulation and descent of the
upper Carbon by introducing air above the Carbon holder substantially as described
under different modifications with reference to Figures 7, 8 and 9 of the
accompanying Drawings.
In witness whereof I the said Legh Sylvester Powell have to this my
Specification set my hand and seal this Nineteenth day of June One thousand
eight hundred and eighty two.
LEGH S. POWELL. (L.S.)