Year: 1886

page_text: Date of Application, 3rd June, 1886.
Complete Left, 3rd Mar., 1887.
Complete Accepted, 6th May, 1887.
I SILVANUS PHILLIPS THOMPSON Doctor of Sciences of the University of London,
of 20 Arundel Gardens W. do hereby declare the nature of this Invention to be as
follows:-
My Improvements constituting this Invention relate to Electric are Lamps and in
particular to the botter construction and arrangement of the electric controlling part
of the regulating mechanism of such lamps and to means and devices in connection
therewith with the object of onabling them always to so regulate the arc as to cause
it to consume Electric energy from the circuit at a constant rate under the most
varying conditions of the olectric supply. An arc lamp cannot give a constant light
unless it draws electric energy from the circuit at a constant rate. As is well known
the two most usual methods of supplying electric energy are (1) "at constant
potential" (2) "with constant current" the former method being designed for
supplying a set of lamps placed in parallel between 2 mains the latter for
supplying a set of lamps in a single circuit. In practice it is not always possible
to secure that either the potential or the current shall be absolutely constant especially
when only a few lamps are in use. Such lamps as have hitherto been constructed will
if adjusted to work on mains at a certain potential give a different amount of light
when placed on mains supplied at a lower potential or if adjusted to work with a
certain current will give a different amount of light if removed to a circuit supplied
with a different current. Moreover the lamps designed to be used "in parallel "on a
constant potential system of mains are not generally adapted to be used and in many
cases cannot be used at all "in series on a constant current circuit and vice versa.
My improved method of controlling the regulation is designed to render the action
of the Lamp equally reliable for work on either system either at high or low potential
in the one case or with either a small or a large current in the other case provided
only there is at least as much electric energy supplied to the circuit as is wanted for
the Lamp.
33
In my improved method of controlling the regulation it is proposed to control the
regulating or feeding mechanism by an Electric mechanism or device of the kind
hereinafter generally described so constructed arranged or combined that it
maintains constant the rate at which electric energy is consumed in the arc.
In arc
rn 01

page_text: lamps as hitherto constructed and known the mechanism is designed to fulfil one of
the following conditions :-
Maintenance of a constant length of arc irrespective of current or potential.
(6) Maintenance of a constatant difference of potential between the Carbon poles
irrespective of the current or of the length or resistance of the arc.
(c) Maintenance of a constant current through the lamp irrespective of the
difference of potential between the poles of the lamp or of the length or resistance of
the arc.
(d) Maintenance of a constant resistance in the arc irrespective of either current
or potential.
None of these conditions even if maintained will ensure the consumption of
Electric energy in the lamp at a constant rate under varying conditions of electric supply.
Now the light given out by a Lamp cannot be maintained constant unless the
consumption of electric energy in the arc goes on also at a constant rate. The rate
of consumption of electric energy in the arc is the product of two factors namely the
current through the lamp and the difference of potentials between its poles or carbons.
The improvements which constitute this Invention consist in means and devices for
working by means of the said product and for maintaining it of constant value, and
in the construction and arrangement of the electric controlling part of the regulating
or feeding mechanism so as to control the said regulating or feeding mechanism in
correspondence with the said product.
The regulating machinery or feed may be of any of the usual known types such as
clockwork provided with a star whool, detent, fan, brake wheel or the like or such as a
clutch worked by a lever, or it may be any other equivalent mechanical device that
permits of the requisite forward movement being given to the carbon pole or poles by
small degrees and admits also of being controlled electrically. It is well known that
such devices and mechanisms and other equivalent devices and mechanisms having
'milar functions can be electrically controlled as for example in certain well known
mps in which a brake piece is lifted from a brake wheel by an electromagnet or in
other lamps where a whole train of wheels is moved or tilted by an Electro magnet
attracting an iron armature attached to the frame of the train so that the last wheel
of the said train is locked or unlocked automatically by the action of the current in
the electro-magnet. Any such system of regulating or feeding machinery may be
used in conjunction with my invention which relates not to any particular train of
mechanisin or system of wheels or levers or clamps or detents or the like but to an
electric device or devices for controlling and actuating such regulating or feeding
machinery as hereinafter set forth.
It is also well known that in arc lamps the regulating or feeding machinery can be
controlled either by an electro-magnet the circuit of which is united in series with
the circuit through the arc or by an electro magnet the circuit of which is united as a
shunt to the latter circuit.
It is also known that the magnetism of an electro magnet is or may be nearly
proportional to the current passing through its coils and that therefore the magnetism
of the controlling electro magnet of Lamp is or may be nearly proportional (1) to
the current passing through the arc if the electro-magnet is arranged as a series
electro magnet (2) to the difference of potential between the poles or carbons of the
lamp if the electro magnet is arranged as a shunt.
If a sensitive regulating or feeding mechanism be controlled by a series magnet
working against a spring or weight that series magnet will cause the mechanism so to
regulate or feed as to maintain a constant or nearly constant current through the arc.
If a sensitive regulating or feeding mechanism be controlled by a shunt magnet
working against a spring or weight that shunt magnet will cause the mechanism so to
regulate or feed as to maintain a constant or nearly constant difference of potential
between the poles of the arc.
It is also known that a series magnet and a shunt magnet inay be employed simul-
taneously in the same lamp, the lamps known as "differential" lamps having both a
series coil and a shunt coil arranged so that the resulting magnetism is approximately

page_text: equal in amount to the difference between the quantities of magnetism separately due
to the two coils. It is also known that a series coil and a shunt coil may be wound
upon one core making a compound wound magnet.
And it is known that if the respective currents that traverse the series coil and
the shunt coils circulate in opposite directions around the core or cores the resulting
magnetism will be approximately equal to the difference between the magnetism
separately due to the two coils and that if the respective currents circulate in the
same direction around the coil or coils the resulting magnetism will be approximately
equal to the sum of the separate effects. But neither the sum nor the difference of
the effects of the two shunt and series coils or of the two shunt and series magnets,
will when applied to the control of the regulating or feeding mechanism maintain
constant the rate of consumption of electric energy simply because the energy
consuined per second in the lamp is proportional neither to the sum nor to the
difference of the two factors but to their product. According to my invention the
regulating or feeding mechanism of the lamp is controlled by an electric device which
works by the product not by the sum or difference of the actions. When electro
magnets are used one of them is connected in series with the arc (so as to have its
magnetism approximately proportional to the current) the other is connected as a
shunt to the Carbons or to the terminals of the lamp (so as to have its magnetism
approximately proportional to the current). These two electro magnets are then
arranged so that their mutual attraction" or repulsion (which is approximately
proportional to the product of their respective magnetisms) shall control the
regulating or feeding mechanism, a spring weight or other similar mechanical device
being applied to afford the requisite constant reaction to separate them when their
attraction diminishes or to cause them to approach when their repulsion diminishes.
One of the two electromagnets may be fixed and the other moveable or both may be
moveable being suitably pivotted or supported.
Or two solenoids one connected in series the other as shunt are used having two
cores so arranged that the product of their mutual force shall actuate the controlling
mechanism. One way of combining the two separate forces due to the two armatures
of the electro magnets or the two cores of the solenoids so that the resultant action
may be proportional to the product of the two, is by the use of such mechanisms as
are employed as integrators for obtaining mechanically the products of two motions.
Or I employ simply two coils or sets of coils of wire one connected in series, the
other as shunt, the mutual force (whether of attraction or repulsion) of the two coils
being similarly used. One way of using two coils is to place one within and at right
angles to the other, so that they tend to move into parallelism by a motion of rotation
as in the instrument known as the electrodynamometer, the moveable coil being
suitably connected with a spring or weight to oppose its rotation. Or I employ an
arrangement or device resembling a dynamo-electric machine consisting of two parts
an armature part and a field magnet part, one being connected in series, the other as
a shunt, the mutual action between the two parts being arranged to be in this as in
all cases approximately proportional to the product of the two separate effects of the
currents in the respective parts, the movement of one or both parts being as before
suitably connected to a spring or weight and being connected by suitable gearing to
control the regulating or feeding mechanism.
The spring or weight whose reaction determines the particular limiting value of the
product at which the regulating mechanism shall be called into action, is arranged to
be capable of adjustment so that the Lamp may be set to consume electric energy at
a large rate when a powerful light is required or at a small rate when a lesser light is
required.

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Lamps.
I SILVANUS PHILLIPS THOMPSON Doctor of Sciences of the University of London
of 20 Arundel Gardens W. 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:-
My Improvements constituting this Invention relate to electric arc Lamps and in 5
particular to the better construction and arrangement of the electric controlling part
of the regulating mechanism of such lamps and to means and devices in connection
therewith with the object of enabling them always to so regulate the arc as to cause it
to consume Electric energy from the circuit at a constant rate under the most varying
conditions of the electric supply. An are lamp cannot give a constant light unless it 1
draws electric energy from the circuit at a constant rate. As is well known the two
most usual methods of supplying electric energy are (1) "at constant potential"
(2) "With constant current the former method being designed for supplying a
System of lamps placed in parallel between two mains the latter for supplying a set of
lamps in a single circuit. In practice, it is not always possible to secure that either 1
the potential or the current shall be absolutely constant, especially when only a few
lamps are in use. Such lamps, as have hitherto been constructed, will if adjusted to
work on mains at a certain potential, give a different amount of light when placed on
mains supplied at a lower potential, or if adjusted to work with a certain current will
give a different amount of light if removed to a circuit supplied with a different 2
current. Moreover, the lamps designed to be used "in parallel" on a constant
potential System of mains are not generally adapted to be used, and in many cases
cannot be used, at all "in series" on a constant current circuit and vice versa. My
improved method of controlling the regulation is designed to render the action of the
lamp equally reliable for work on either System, either at high or low potential in the a
one case, or with either a small or a large current in the other case, provided only
there is at least as much electric energy supplied to the circuit as is wanted for the
lamp. According to my Invention the regulating or feeding mechanism is controlled
by an Electric mechanism or device, of the kind hereinafter described, so constructed
arranged or combined that it maintains constant the rate at which electric energy is
consumed in the Arc. In Arc lamps, as hitherto constructed, and known the
mechanism is designed to fulfil one of the following conditions.
Maintenance of a constant length of are, irrespective of current or potential.
Maintenance of a constant difference of potential between the carbon polos
irrespective of the current or of the length or resistance of the arc.
(c) Maintenance of a constant current through the lamp irrespective of the difference
of potential between the poles of the lamp, or of the length or resistance of the arc.
(d) Maintenance of a constant resistance in the arc irrespective of either current or
potential.
None of these conditions, even if maintained will ensure the consumption of electric
energy in the lamp at a constant rate under varying conditions of electric supply.

page_text: Now the light given out by a lamp cannot be maintained constant unless the
consumption of electric energy in the arc goes on also at a constant rate.
The rate of consumption of electric energy in the arc is the product of two factors
namely the current through the lamp and the difference of potentials between its
poles or carbons. The improvements which constitute this Invention consist in means
and devices for working by means of the said product and for maintaining it of
constant value and in the construction and arrangement of the electric controlling
part of the regulating or feeding mechanism so as to control the said regulating or
feeding mechanism in correspondence with the said product.
The regulating machinery or feed may be of any of the usual known types such as
clockwork provided with a star-wheel detent, fan, brake-wheel or the like, or such as
a clutch worked by a levor, or it may be any other equivalent mechanical device that
permits of the requisite forward movement being given to the carbon pole or poles by
small degrees, and admits also of being controlled electrically. It is well known that
such or equivalent devices and mechanisms can be electrically controlled, as for
example in certain well known lamps in which a brake-piece is lifted from a brake-
wheel by an electro magnet or in other lamps where a whole train of wheels is moved
or tilted by an electro magnet attracting an armature attached to the frame of the
train so that the last wheel of the said train is locked or unlocked automatically by the
action of the current in the electro magnet. Any such system of regulating or feeding
machinery may be used in conjunction with my Invention which relates not to any
particular train of mechanism or system of wheels or levers or clamps or detents or
the like but to an electric device or devices for controlling and actuating such
regulating or feeding machinery as hereinafter set forth. It is also well known that
in arc lamps the regulating or feeding machinery can be controlled either by an
electro magnet the circuit of which is united in series with the circuit through the
arc, or by an electromagnet the circuit of which is united as a shunt to the latter
circuit.
It is also known that the magnetism of an electro magnet is or may be nearly
proportional to the current passing through its coils and that therefore the magnetism
of the controlling electro magnet of a lamp is or may be nearly proportional (1) to
the current passing through the are if the cluctro magnet is arranged as a series
electromagnet (2) to the difference of potential between the poles or carbons of the
lamp if the electro magnet is arranged as a shunt.
If a sensitive regulating or feeding mechanism be controlled by a series magnet
working against a spring or weight, that series magnet will cause the mechanism so to
regulate or feed as to maintain a constant or nearly constant current through the arc.
If a sensitive regulating or feeding mechanism be controlled by a shunt magnet
working against a spring or weight, that shunt magnet will cause the mechanism so to
regulate or feed, as to maintain a constant or nearly constant difference of potential
between the poles of the arc.
It is also known that a series magnet and a shunt magnet may be employed
simultaneously in the same lamp the lamps known as "differential" lamps having both
a series coil and a shunt coil arranged so that the resulting magnetism is approximately
equal in amount to the difference between the quantities of magnetism separately due
to the two coils. It is also known that a series coil and a shunt coil may be wound
upon one core making a compound wound magnet.
And it is known that if the respective currents that traverse the series coil and the
shunt coils circulate in opposite directions around the core or cores the resulting
magnetism will be approximately equal to the difference between the magnetism
separately due to the two coils, and that if the respective currents circulate in the
same direction around the coil or coils, the resulting magnetism will be approximately
equal to the sum of the separate effects. But neither the sum nor the difference of the
effects of the two shunt and series coils or of the two shunt and series magnets will
when applied to the control of the regulating or feeding mechanism maintain constant
the rate of consumption of electric energy, simply because the energy consumed per

page_text: second in the lamp is proportional neither to the sum nor to the difference of the two
factors but to their product.
According to my invention the regulating or feeding mechanism of the lamp is con-
trolled by an electric device which works by the product not by the sum or difference
of the two actions. When electromagnets are used one of them is connected in
series with the arc (so as to have its magnetism approximately proportional to tho
current) the other is connected as a shunt to the carbons or to the terminals of the
lamp (so as to have its magnetism approximately proportional to the current). These
two electro magnets are then arranged so that their mutual attraction or repulsion,
(which is approximately proportional to the product of their respective magnetisms)
shall control the regulating or feeding mechanism, a spring, weight, or other similar
mechanical device being applied to afford the requisite constant reaction to separate
them when their attraction diminishes or to cause them to approach when their repul-
sion diminishes. One of the two electromagnets may be fixed and the other moveable,
or both may be moveable, being suitable pivotted or supported.
Or two solenoids, one connected in series, the other as shunt, are used, having two
cores, so arranged that the product of their mutual force shall actuate the controlling
mechanism. One way of combining the two separate forces due to the two armatures
of the electromagnets or the two cores of the solenoids so that the resultant action
may be proportional to the product of the two, is by the use of such mechanisms as
are employed as integrators for obtaining mechanically the products of two motions.
Or I employ simply two coils or sets of coils or wire, one connected in series the other
as shunt, the mutual force (whether of attraction or repulsion) of the two coils being
similarly used. One way of using two coils is to place one within and at right angles
to the other, so that they tend to move into parallelism by a motion of rotation as in
the instrument known as the electrodynamometer, the moveable coil being suitably
connected with a spring or weight to oppose its rotation. Or I employ an arrange-
ment or device resembling a dynamo-electric machine consisting of two parts, an
armature part and a field magnet part one being connected in series, the other as a
shunt, the mutual action between the two parts being arranged to be in this, us in all
cases approximately proportional to the product of the two separate effects of the
currents in the respective parts, the movement of one or both parts being as before
suitably connected to a spring or weight, and being connected by suitable gearing to
control the regulating or feeding mechanism. The spring or weight whose reaction
detormines the particular limiting value of the product at which the regulating
mechanism shall be called into action, is arranged to be capable of adjustment so that the
lamp may be set to consume electric energy at a large rate when a powerful light is
required, or at a small rate when a lesser light is required.
The accompanying drawings shew how my Invention may be practically carried
into effect but it is to be understood that I do not limit myself to the precise details
or mechanical parts which I have illustrated and hereinafter describe.
Figure I shews a fine wire coil Z Z wound as a shunt and mounted upon a core z
turning upon knife edge centres ¹ and counter-weighted at -S S is a fixed coarse
wire coil wound in series. The opposed poles of the two coils or of opposite polarity
their attraction serving to pull down a spiral spring p and let off a detent (or the
equivalent) of the feeding mechanism of the lamp. The detent and wheel of the
feeding mechanism are shewn at d but the remaining parts it is unnecessary to shew
as they may bo of any convenient or preferred kind and in themselves alone are not of
my present Invention. The attraction of the cores of the said coils will be propor-
tional to the product of the currents in the two coils hence as the current in the shunt
coil ZZ is proportional to the potential at its ends if the magnetisation of the iron
cores be assumed to be proportional to the currents flowing respectively around them,
the attraction between their poles will be proportional to the product of the potential
at the ends of Z Z multiplied into the current in S S.
Figure 2 illustratos an application of my Invention to an arc lamp fed by the falling
of the upper carbon holder with rack and train of wheels driven by the weight of the

page_text: upper carbon and holder. The detent d is in this case released by the inward move-
ment of the shunt wound coil Z Z (arranged within the series wound coil S S) when its
attraction by the cores of the coil S S attains a certain value.
This attraction will be proportional to the product of the potential between the ends
of Z Z into the current in S S. Hence the feeding mechanism is set into action
whenever this product falls below its normal value; thereby maintaining the con-
sumption of energy in the are at an approximately constant value.
Having now particularly described and ascertained the nature of my said Invention
and in what manner the same is to be performed I declare that what I claim is :-
First In an electric arc lamp the application to the feeding or regulating
mechanisin of an electric device in which a series coil and a shunt coil act jointly so
as to produce an attractive force proportional (or approximately so) to the product of
the current in the one into the difference of potential at the terminals of the other.
Second In the feeding or regulating mechanism of an electric arc lamp the
combination of an opposing spring or a counterpoise weight with an electric device
in which the attractive force is proportional (or approximately so) to the product of the
two currents passing respectively in a coil in series with the arc and in a coil in shunt
with the arc.
Third The arrangements illustrated by the accompanying drawings for the
purpose described.
Dated this 3rd day of March 1887