IMPROVEMENTS IN ELECTRIC LAMPS AND APPARATUS USED IN CONNECTION WITH ELECTRIC LIGHTING
Year: 1882

page_text: LETTERS PATENT to Rookes Evelyn Bell Crompton, of the Mansion House
Buildings, Queen Victoria Street, in the City of London, Engineer, for an
Invention of "IMPROVEMENTS IN ELECTRIC LAMPS AND APPARATUS USED IN
CONNECTION WITH ELECTRIC LIGHTING."
PROVISIONAL SPECIFICATION left by the said Rookes Evelyn Bell
Crompton at the Office of the Commissioners of Patents on the 24th January
1882.
"
ROOKES EVELYN BELL CROMPTON of the Mansion House Buildings Queen
Victoria Street in the City of London Engineer. IMPROVEMENTS IN ELECTRIC
LAMPS AND APPARATUS USED IN CONNECTION WITH ELECTRIC LIGHTING."
arç
The first portion of my invention relates to that class of electric lamps called
regulator lamps in which straight rods of carbon are used as the electrodes.
In one form of my invention I use as the carrier for one of the carbons a
cylindrical rod having a rack cut on one side of it hereafter called the rack rod.
This rod passes through and is guided by openings at top and bottom of a
suitable framework of rectangular or other convenient form hereafter called the
main frame.
This rack rod also passes through a smaller frame work placed within the main
frame, this smaller frame carries a train of wheel work brake wheel and brake
and is hereafter called the gearing frame.
The rack on the rod gears into the first wheel of the train and the last wheel
which is usually the third wheel is a brake wheel having a smooth periphery but
fitted with weighted tangential springs so arranged that any excessively quick
rotation of this brake wheel causes the springs to fly outwards strike against the
brake and so retard the motion and thus the speed of rotation is prevented from
becoming excessive.
The brake is a light metallic lever of convenient shape having reference to the
relative position of the parts of the lamp and so pivotted between the cheeks of
the gearing frame that one end can press upon the periphery of the brake wheel
Dmine 31

page_text: •
and so arrest its movement the other end which is formed of soft iron being so
· placed that it can be attracted by an electro magnet, hereafter called the feed
magnet when the iron end of the lever is thus attracted and brought up to the pole
of the feed magnet the other end is lifted off the brake wheel and the brake wheel
being thus released the rack rod falls and the lamp feeds. The attractive force of
the feed magnet is counterbalanced by a spring or other equivalent mechanical
device so that the brake rests on the brake wheel so long as the current is passing
in the normal way between the electrodes. This spring is called the regulating
spring.
In place of a rack rod and its gearing I sometimes employ a rod with suitable
frictional gearing.
The gearing frame is free to rise and fall through a certain distance of stroke
within the main frame and is lifted through this stroke by the action of a larger
electro magnet called the main magnet.
The length of this stroke of the gearing frame can be adjusted by stops.
The main magnet is wound with coarse wire and the main current to or from
the arc passes through its helix.
The feed magnet is wound with a great length of fine high resistance wire and
the two ends of this fine wire are connected up to the two terminals of the lamp so
that the current passes through the fine wire as a shunt or derived circuit parallel
to the current through the arc or main circuit.
The action of the lamp is as follows:
When not at work and no current passing. The gearing frame rests within the
main frame in its lowest position the rack rod being free to descend through it
until its motion is arrested by its carbon resting on the lower carbon which may
be carried on a separate bracket or by the side rods as hereafter set forth.
When the current is passed through the lamp it passes through the helix of the
¯main¯magnet-lifts-the-gearing frame and with it the rack_rod through its proper
stroke and thus parts the carbons sufficiently to establish the arc, and the lamp
commences to burn. The action of lifting the gearing frame brings the soft iron
end of the brake within the attractive influence of the feed magnet so long as the
difference of potential at the two sides of the are remains normal the fractional
part of the current which passes by way of the fine wire of the feed magnet is only
sufficient to give it attracting power enough to approximately balance the opposing
force of the regulating spring which presses the brake on to the brake wheel.
Immediately however when by the action of wasting away the carbons the
difference of potential exceeds that for which the regulating spring is regulated the
feed magnet overcomes the spring lifts the brake off the brake wheel and allows
the rack rod to descend until the difference of potential becomes again normal and
preponderance of the regulating spring over the feed magnet is again established.
It is evident that two or more rack rods each carrying carbons may be mounted
in the same framework so as to form a double or treble lamp and so obtain
increased hours of burning.
The current being switched from one to the other by an ordinary automatic cut
out switch or relay mounted in the upper part of the lamp. I prefer to mount the
above described main frame with its mechanism and rack rod in a pair of side rods
connected by cross heads top and bottom the top cross head being so mounted with
insulating carriers or hooks that the lamp can be supported or suspended from it
the bottom cross head carrying the lower carbon holder.
Where the rack rod is of great length as when it is desired to burn from
20 inches of carbon upwards it is necessary to guide it at its lower end this I
effect by mounting on it just above the carbon holder a loose crosshead having
roller guides nt each end the peripheries of the roller being turned to fit and so
guide themselves on the inner edges of the side rods.
I can further utilize these side rods as guides on which the protecting lantern or
glass globe can slide up and down so as to give ready access to the carbons.
I accomplish this by mounting the lantern or glass globe on a ring or frame of

page_text: suitable form which is fitted to slide easily and steadily up and down the side rods
by having shoe slides fixed to the inner side of this ring which shoe slides embrace
and are properly guided on the outer edges of the sido rods the lantern or glass
globe can bo counterpoised either by weights or by springs so that it can rest
indifferently in any position or it can be raised and lowered by chains working over
pulleys and clamped or fixed in any position by spring or screw catches or other
suitable contrivances.
In another form of my invention more particularly suitable for lighthouse
military naval and marine purposes I place the main frame and contained mechanism
below the light itself.
The general arrangements may be the same as heretoforo described. with the
following alterations and additions.
I make the side rods to project wholly above the main frame and connect them
at their upper ends at a suitable distance above the main frame by a cross head
having mounted on it differential pulleys over which pass cords, chains or wires
connecting the two carbon carriers in such a manner that the descent of the upper
carrier and carbon draws up the lower carrier and carbon at a proportionate rate
of travel so arranged as to compensate for the unequal consumption of the carbons
and so maintain the are in an approximately fixed position. In this case the
lower carbon carrier is a rack rod mounted with a gearing frame as already
described but with obvious changes owing to the reversed position of the mechanism
the function of the main magnet in this case being to draw down the gearing
frame instead of lifting it.
Another portion of my invention consists in putting the main magnot which
does the work of establishing the arc on an alternative circuit or bye path along
which the whole of the current can pass when the arc is not established but from
which the current is diverted so soon as the arc is established.
To offect this in any of the arrangements herein before described I cause tho
gearing frame to bo sustained in its highest position instead of its lowest one by
means of a spring of considerable strength.
The main magnet arranged as now described is so placed as to oppose this spring
so that when this magnet acts it draws the carbons into contact instead of drawing
them apart as heretofore.
The current in entering the lamp can fork along two paths one by way of the
main magnet and from thence direct out from the lamp to the lines the other path
being by way of the helix of a relay or cut out magnet and thence by the carbous
to the line.
When the current passes by the cut out magnets and carbons the cut out
automatically switches the current off from the main magnet so that the one path
leading to the carbons alone remains open.
The action is as follows: The current entering the lamp finds only one of the
two paths open to it as the carbons are kept apart by the spring above mentioned
and therefore passes wholly by the main magnet and thus draws together the
carbons and immediately on this taking place the current being able to pass by
the carbons, the cut out acts, cuts out the main magnet and thus releases the
carbons which fly apart to form an arc of the normal length. All subsequent feed
movements are carried on by the feed mechanism before described.
In this arrangement the main magnet only comes into action to re-establish the
arc if by any accident it should be extinguished. One advantage of this arrange-
ment is that the main magnet not being always in circuit the waste of energy in
overcoming the resistance of its helix is avoided.
In the case of the second arrangement before mentioned:-
When I place the mechanism for lighthouse or other purposes below the light
he gearing frame is kept in its lowest position by its own weight aided if
ecessary by a spring when the magnet acts it draws the carbons into contact by
aising the gearing frame and with it the lower carbon.
Another portion of my invention relates to a device for preventing the machines

page_text: electric circuit and lamps in electric lighting installations from acquiring a static
charge of high potential and so becoming capable of giving violent and even
dangerous shocks to persons accidentally touching some part of them and thus
momentarily putting the highly charged system in electric connection with the
earth. It is probable that this static chargo is due to the fact that where there is
an electric discharge through gaseous media there is an absence of symmetry in the
behaviour of the current and the amounts of free electricity escaping into the
atmosphere are not the same for positive and negative electricity so that there is a
continual tendency to accumulate a charge of that kind of electricity which escapes
less readily than the other. To remedy this I use a leakage or relief wire which
consists of a fine wire of considerable length and high resistance the two ends of
which are respectively in metallic connection with earth and with some portion of
the metallic circuit through which the current passes the resistance of this wire is
made so high that it would not affect the behaviour of the lamp even if some other
part of the circuit were accidentally placed in connection with the earth. In this
way the part of the circuit with which it is connected will be kept at the saine
potential as the earth without any of the dis-advantages of an ordinary earth
connection.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Rookes Evelyn Bell Crompton in the Great Seal Patent Office on
the 24th July 1882.
ROOKES EVELYN BELL CROMPTON of the Mansion House Buildings Queen
Victoria Street in the City of London Engineer. "IMPROVEMENTS IN ELECTRIC
LAMPS AND APPARATUS USED IN CONNECTION WITH ELECTRIC LIGHTING."
The first portion of my invention relates to that class of electric lamps called
are regulator lamps in which straight rods of carbon are used as the electrodes.
In one form of my invention I use as the carrier for one of the carbons a
cylindrical rod having a rack cut on one side of it hereafter called the rack rod.
This rod passes through and is guided by openings at top and bottom of a
suitable framework of rectangular or other convenient form hereafter called the
main frame.
This rack rod also passes through a smaller framework placed within the main
frame, this smaller frame carries a train of wheelwork, brake wheel and brake and
is hereafter called the gearing frame.
The rack on the rod gears into the first wheel of the train and the last wheel
which is usually the third wheel is a brake wheel having a smooth periphery but
fitted with weighted tangential springs so arranged that any excessively quick
rotation of this brake wheel causes the springs to fly outwards strike against the
brake and so retard the motion and thus speed of rotation is prevented from
becoming excessive.
The brake is a light metallic lever of a convenient shape having reference to the
relative position of the parts of the lamp and so pivotted between the cheeks of the
gearing frame that one end can press upon the periphery of the brake wheel and so
arrest its movement the other end which is formed of soft iron being so placed that
it can be attracted by an electro magnet hereafter called the feed magnet when the
iron end of the lever is thus attracted and brought up to the pole of the feed
magnet the other end is lifted off the brake wheel and the brake wheel being thus
released the rack rod falls and the lamp feeds. The attractive force of the feed
magnet is counterbalanced by a spring or other equivalent mechanical device so
that the brake rests on the brake wheel, so long as the current is passing in the
normal way between the electrodes. This spring is called the regulating spring.
In place of a rack rod and its gearing I sometimes employ a rod with suitable
frictional gearing.
The gearing frame is free to rise and fall through a certain distance of stroke,
within the main frame and is lifted through this stroke by the action of a larger
electro magnet called the main magnet.
The length of this stroke of the gearing frame can be adjusted by stops.
The main magnet is wound with coarse wire and the main current to or from the
arc passes through its helix.
This use of the feed magnet could obviously be applied to any method of
connecting the rack rod with the gearing frame, provided that the rack rod
could not descend until the brake had freed the brake wheel and that the motion
of the rack rod when the brake wheel was freed did not affect the position of the
gearing frame.
The feed magnet is wound with a great length of fine high resistance wire, and.
the two ends of this fine wire are connected up to the two terminals of the lamp so
that the current passes through the fine wire as a shunt or derived circuit parallel
to the current through the arc or main circuit.
The action of the lamp is as follows:
When not at work and no current passing. The gearing frame rests within the
main frame in its lowest position, the rack rod being free to descend through it
until its motion is arrested by its carbon resting on the lower carbon which may
be carried on a separate bracket, or by the side rods as hereafter set forth..

page_text: When the current is passed through the lamp it passes through the helix of the
main magnet lifts the gearing frame and with it the rack rod through its proper
stroke and thus parts the carbons sufficiently to establish the arc and the lamp
commences to burn. The action of lifting the gearing frame brings the soft iron
end of the brake within the attractive influence of the feed magnet. So long as
the difference of potential at the two sides of the arc remains normal, the fractional
part of the current which passes by way of the fine wire of the feed magnet is
only sufficient to give it attracting power enough to approximately balance the
opposing force of the regulating spring which presses the brake on to the brake
wheel.
Immediately however when by the action of wasting away the carbons the
difference of potential exceeds that for which the regulating spring is regulated the
feed magnet overcomes the spring lifts the brake off the brake wheel and allows
the rack rod to descend until the difference of potential becomes again normal
and preponderance of the regulating spring over the feed magnet is again
established.
It is evident that two or more rack rods each carrying carbons may be mounted
in the same frame work so as to form a double or treble lamp and so obtain
increased hours of burning; the current being switched from one to the other by
an ordinary automatic cut out switch or relay mounted in the upper part of the
lamp.
I prefer to mount the above described main. frame with its mechanism and rack
rod in a pair of side rods connected by cross heads top and bottom. The top cross
head being so mounted with insulating carriers or hooks that the lamp can be
supported or suspended from it, the bottom cross head carrying the lower carbon
holder.
Where the rack rod is of great length as when it is desired to burn from 20
-inches of carbon_upwards_it_is_ necessary to guide it at its lower end this I effect
by mounting on it just above the carbon hokler a loose cross head having roller
guides at each end the peripheries of the rollers being turned to fit and so guide
themselves on the inner edges of the side rods. I can further utilize these side rods
as guides on which the protecting lantern or glass globe can slide up and down so
as to give ready access to the carbons.
I accomplish this by mounting the lantern or glass globe on a ring or frame of
suitable form which is fitted to slide easily and steadily up and down the side rods
by having shoe slides fixed to the inner side of this ring which shoe slides embrace
and are properly guided on the outer edges of the side rods, the lantern or glass
globe can he counterpoised either by weights or by springs so that it can rest
indifferently in any position or it can be raised and lowered by chains working
over pulleys and clamped or fixed in any position by spring or screw catchies or
other suitable contrivances.
In another form of my invention more particularly suitable for lighthouse
military, naval and marine purposes I place the main frame and contained
mechanisın below the light itself.
The general arrangements may be the same as heretofore described with the
following alterations and additions.
I make the side rods to project wholly above the main frame and connect them
at their upper ends at a suitable distance above the main frame by a cross head
having mounted on it differential pulleys over which pass cords chains or wires
connecting the two carbon carriers in such a manner that the descent of the upper
carrier and carbon draws up the lower carrier and carbon at a proportionate rute
of travel so arranged as to compensate for the unequal consumption of the carbons
and so maintain the arc in an approximately fixed position. In this case the lower
carbon carrier is a rack rod mounted with a gearing frame as already described but
with obvious changes owing to the reversed position of the mechanism the function
of the main magnet in this case being to draw down the gearing frame instead of
lifting it.

page_text: Another portion of my invention consists in putting the main magnet which
does the work of establishing the are on an alternative circuit or bye path along
which the whole of the current can pass when the arc is not established but from
which the current is diverted so soon as the arc is established.
To effect this in the first arrangement hereinbefore described I cause the gearing
frame to be sustained in its highest position instead of its lowest one by means of
a spring of considerable strength.
The main magnet arranged as now described is so placed as to oppose this spring
so that when this magnet acts it draws the carbons into contact instead of drawing
them apart as heretofore.
The current in entering the lamp can fork along two paths, one by way of the
main magnet and from thence direct out from the lamp to the line the other path
being by way of the helix of a relay or cut out magnet and thence by the carbons
to the line.
When the current passes by the cut out magnets and carbons, the cut out
automatically switches the current off from the main magnet so that the one path
leading to the carbons alone remains open.
The action is as follows:-The current entering the lamp finds only one of the
two paths open to it as the carbons are kept apart by the spring above mentioned
and therefore passes wholly by the main magnet and thus draws together the
carbons and immediately on this taking place the current being able to pass by the
carbons, the cut out acts, cuts out the main magnet and thus releases the carbons
which fly apart to form an are of the normal length. All subsequent feed move-
ments are carried on by the feed mechanism before described. In this arrangement
the main magnet only comes into action to re-establish the arc if by any accident
it should be extinguished. One advantage of this arrangement is that the main
magnet not being always in circuit the waste of energy in overcoming the
resistance of its belix is avoided.
In the case of the second arrangement before mentioned when I place the
mechanism for lighthouse or other purposes below the light the gearing frame is
kept in its lowest position by its own weight aided if necessary by a spring when
the magnet acts it draws the carbons into contact by raising the gearing frame and
with it the lower carbon.
Another portion of my invention relates to a device for preventing the machines,
electric circuit and lamps in electric lighting installations from acquiring a static
charge of high potential and so becoming capable of giving violent and even
dangerous shocks to persons accidentally touching some part of them and thus
momentarily putting the highly charged system in electric connection with the
earth. It is probable that this static charge is due to the fact that whero there is
an electric discharge through gaseous media there is an absenco of symmetry in
the behaviour of the current and the amounts of free electricity escaping into the
atmosphere are not the same for positive and negative electricity so that there is a
continual tendency to accumulate a charge of that kind of electricity which
escapes less readily than the other. To remedy this I use a leakage or relief wire
which consists of a fine wire of considerable length and high resistance the two
ends of which are respectively in metallic connection with earth and with some
portion of the metallic circuit through which the current passos. The resistance of
this wire is made so high that it would not affect the behaviour of the lamps even
if some other parts of the circuit were accidentally placed in connection with the
earth. In this way the part of the circuit with which it is connected will be kept
at the same potential as the earth without any of the disadvantages of an ordinary
earth connection.
The very numerous different methods of applying this relief wire require no
special description, to instance one I weave into the suspending cord of each of the
lanterns containing the arc lamps an extromely fine copper wire having a total
resistance of upwards of 10,000 ohms, one end of this is in electrical connection
with the positive terminal of the lamp and the other is in electrical connection
.

page_text: with the earth either by connecting it to the gas pipes or other iron work of the
building or in any other suitable manner insuring that the electrical connection
with the earth is perfect.
Another method of applying the relief wire is to prepare a coil of fine wire
of the same high resistance connecting one end with the positive brush of the
machine and the other with the earth as aforesaid.
The accompanying drawings illustrate one method of constructing the lamp.
Figure 1 is a front view of a lamp constructed according to my Invention drawn
to a scale of one fourth the natural size. Figure 2 is a similar view of portions of
the same drawn to a larger scale in order that the parts of the mechanism may be
more clearly seen and Figure 3 shows the brake wheel mechanism, brake and a
portion of its electro magnet enlarged to full size.
In Figure 2. a a is a rack rod guided through openings at top and bottom of the
framework A. A. this rack rod passes through the smaller frame bb placed as
herein shewn and called the gearing frame, the rack on the rod gears into the first
wheel c of the train the last wheel of which (usually the third wheel) c³ is a brako
wheel having a smooth periphery fitted with tangential spring flies or flaps d d so
arranged that any quick rotation causes the spring flies or flaps to fly outwards
against the brake e. This brake e is a slight metallic lover of a convenient shape
and is fitted between the cheeks of the gearing framo at F, the portion el is made of
soft iron, it is attracted by the electro magnet C. C. which is called the feed magnet
the attractive force of this feed magnet is counterbalanced by the spring called.
the regulating spring. The main magnet G G is wound with coarse wire through
which the main current to the are passes, the feed magnets C. C. are wound with a
great length of fine wire of high resistance and the two ends of this are connected
up to the two terminals of the lamp, the main frame A. A is supported by the
_ferrules or stops H. H. H. H between the two side rods I I connected below the
lamp to the cross pieces J and above the lamp to a crosshead. When the lamp is
not to be a focus keeping one, the lower carbon is simply fixed into the cross piece J
by any suitable form of carbon holder, if however it is desired that the lamp
should keep focus then 1 arrange that the lower carbon h should rise at half the
rate of travel, that the upper carbon descends.
I accomplish this by connecting a cord to the rack rod a a at or near its lowest
extremity. This cord lies in a groove in the side of the rack rod on the opposito
side to the rack teeth, it passes over the two pulleys i i down through one of the
tubular side rods and over the directing pulleys up to a fixed point where
it is secured it is evident that by this arrangement as the rack rod a a descends it
will draw up the lower carbon holder and with it the carbon h at half its rate of
travel, this lower carbon is guided at or near its point by the porcelain washer K,
electrical connection is made to the lower carbon holder by the flexible con-
nection m. The mechanism of the lower carbon holder is surrounded and protected
by the tube M this tube M also forms a convenient guide on which the lantern or
globe surrounding and protecting the light can slide up and down to give access to
the carbons. In cases where alternating currents are used, where the rate of
consumption of the two carbons is the saine the pulley can be dispensed with
and the cord attached at once to the lower end of the lower carbon holder.
I will now proceed to describe the action of the lamp when in use; when no
current is passing the gearing frame b b rests within the main frame in its lowest
position, the rack rod a a being free to descend through it until stopped by its
carbon resting on the lower carbon. The arrangement in the drawing being
shewn as of a focus keeping lamp, when the current enters the lamp it passes
through the helix of the inain magnet G lifts the gearing frame b band with it the
rack rod a a through its proper stroke, it thus parts the carbons and establishes
the arc and the lamp commences to burn, when thus lifted the gearing frame brings
the soft iron end e of the brake e within the attractive influence of tho feed
magnets C C. So long as the difference of potential at the two sides of the arc
remains normal, the current which passes through the feed magnets C. C. is only

page_text: sufficient to give it attractive power to approximately balance the opposing
regulating spring f which presses the brake e on the brake wheel c³.
Figure 4 shows another portion of my Invention in which the main magnet G. G.
which does the work of establishing the arc is on an alternative or cut out circuit, the
general arrangement being the same as before described There are however these
necessary additions, the main magnets G. G. work in a reversed manner, that is to
say, they drag the gearing frame b b downwards against the main spring O,
N. N. is a separate magnet called a cut out magnet having a hinged armature
which when attracted by it breaks the direct circuit through the main magnets G. G.
The action of the parts of this arrangement is as follows. When no current is
passing; the carbons having been properly adjusted in the lamp remain a short
distance apart, this distance being such that when the gearing frame is pulled down
by the main magnets the points of the carbons can touch; when the current passes
the armature p of the cut out magnets N. N. remains in contact with the contact
piece n and the current can pass direct through the main magnets G. G. At this
time it cannot pass through the cut out N. N. because the path from it by way of
the arc is still open, immediately however the current passing by way of the main
magnets G. G. drags down the carbons so as to complete the circuit through the
electro magnet N. N. then this last magnet acts and by drawing up this armaturo p
cuts the main magnets G. G. out of the circuit and the spring O lifts the frame and
thus establishes the arc which once started continues to burn until the difference
of potential becomes greater than that for which the lamp is regulated, then the
feed mechanism comes into action in the usual manner.
If by any cause the lamp should become extinguished the armature p of the cut
out magnet again falls, the main magnets again act, the carbons are dragged
together and the are reformed.
Having thus described the nature of my Invention and means employed by me
in carrying the same into effect, I would have it understood that what I claim is
1. The use in an electric regulator lamp of a combination of a gearing frame
moved by an electro-magnet or solenoid in the main circuit with feed mechanism
consisting of the brake wheel and parts operating there with which feed mechanisin
is set in motion by the action of an electro-magnet or solenoid on a shunt or
derived circuit the whole forming a means for controlling the length of the are
substantially as described.
2. The arrangement of the main magnet for forming the are of electric lamps on
the alternative or cut out circuit substantially as described.
3. The improved electric lamps formed by the combination of either or both of
the improvements herein above claimed in my first and second claiming clauses
with one or some of the devices or arrangements for the other portions of the
lamp herein described.
4th The provision of a discharge circuit of extremely high resistance to provide
for the discharge of any static charge which may accumulate in an electric circuit
used for the purpose of electric lighting substantially as described.
In witness whereof I the said Rookes Evelyn Bell Crompton have hereunto
set my hand and seal this Twenty fourth day of July in the year One
thousand eight hundred and eighty two.
Witness
ROOKES EVELYN BELL CROMPTON. (L.S.)
ALFRED GEORGE BROOKES
59 Chancery Lane
London.