IMPROVEMENTS IN AND RELATING TO APPARATUS FOR THE GENERATION, REGULATION, AND UTILIZATION OF ELECTRIC CURRENTS
Year: 1882

page_text: LETTERS PATENT to William Robert Lake, of the firm of Haseltine, Lake,
& Co, Patent Agents, Southampton Buildings, London for an Invention
of."IMPROVEMENTS IN AND RELATING TO APPARATUS FOR THE GENERATION,
REGULATION, AND UTILIZATION OF ELECTRIC CURRENTS " Communicated
to him from abroad by Elihu Thomson, of New Britain, Connecticut, United
States of America
:
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 6th July 1882.
"
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, & C°, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN AND RELATING TO APPARATUS
FOR THE GENERATION, REGULATION, AND UTILIZATION OF ELECTRIC CURRENTS
[A communication to him from abroad by Elihu Thomson, of New Britain,
Connecticut, United States of America]
My invention relates to electric generators, motors; regulators, and lighting
apparatus or mechanism, and comprises various improvements as hereinafter
specified.
I employ electric generators composed of a field-magnet, a revolving armature
wound with three coils or helices of insulated wire connected to form a single
three-branched conductor, a commutator consisting of three insulated removable
segments, four commutator-brushes, forming two pairs of diametrically opposite
brushes on the commutator and adjustable around the axis of the commutator;
in some generators I use a peculiar air-jet attachment serving to conserve the
insulation at the slots between the commutator segments.
and
I use for the generating machine regulating apparatus consisting of a peculiar
electro-magnetic attachment which adjusts the position of the commutator-brushes
around the commutator so as to preserve a uniform current strength notwith-
standing changes in the resistance of the circuit over which the generator works.
I operate my arc-lamps and incandescent lamps in series. The arc-lamps are

page_text: constructed with devices for regulating the distance apart of the two carbon
electrodes, the upper one being alone adjusted; they comprise a very sensitive
magnet system, also a very sensitive lifting and feeding clamp which secures what
I term an automatic friction feed of the carbon rod so that the approach of the
carbons, when consuming, is slow and gradual. My lamp also comprises a safety 5
device for effecting certain approach of the carbons when by accident an abnormally
long arc is formed in the lamp.
The incandescent lamps are constructed of low resistance and are worked in
series, sometimes in circuit with arc lamps. They consist of an enclosing sealed
globe of glass exhausted containing a rod of carbon of peculiar structure in 1
combination with various appliances as hereinafter described.
I construct the machine or generator with a suitable framing and with iron bars
forming a grating around the same. The field-magnets are constructed with iron
shells surrounded by wire coils and enclosing the spherical armature between their
opposed curved surfaces. There is a regulator magnet for moving the brushes and 1
a small rotary blower mounted upon the shaft for furnishing an air-blast for the
preservation of the commutator insulation.
The armature is composed of a core of iron consisting of two dishing ends or
flanges; these plates sustain bridges connecting the said ends and sustaining iron
wire or bands exterior to them, the whole forming an oblate spherical iron shell.
Outside of this shell the insulated copper wire is wound. Openings in the shells
of the field-magnets allow circulation of air outwards from the armature.
The shells are flanged to unite with the bars and the frame. The wires from the
armature are carried through the shaft to the commutator.
Besides the magnetizing coils I also frequently encircle the magnets with a
closed band of copper or closed conductor, forming a complete circuit of low
resistance.
This devise prevents oscillations of magnetism taking place suddenly and
steadies the generated current. The bands may be of sheet copper or wire.
Projections from the armature core hold the encircling coils in place. Strong
wire bands are also used to serve the same end. The coils underlie and overlie one
another near the shaft.
The connections are so arranged that the terminals of the armature helices or
coils are each attached to a segment of a three-segment commutator. The coils
pass the neutral point in similar positions successively at 120° of rotation apart.
I construct another form of armature consisting of a ring or band carried by spokes
and with six coils wound on the said ring or band. The connections in this armature
are similar to those hereinabove described.
In another form or modification of the said armature, coils are wound upon six
projections from a central hub. The armature is built of numerous plates and its
coils are connected as herein before described in three sets and three free ends.
It will thus be seen that the armature coil system is simply a single three
.branched 'conductor, the free ends of the branches being carried to the corresponding
commutator segments, one to each segment.
:
The generated current is taken up by the brushes resting on the commutator.
To diminish the spark produced at the slots in the commutator when the brushes
are badly adjusted I sometimes provide a triple condenser; or condenser having
three opposed foils. These foils are carefully insulated and singly connected to
each segment of the commutator. Each foil should represent from 10 to 20 square
feet of coated surface of average condensing capacity. The action is to condense
and obliterate the spark of rupture. If however the commutator brushes are kept
adjusted the spark produced is slight even without the condenser, and when the
"air blast" attachment herein described is used the spark is almost annihilated,
and the condenser is not needed.
In some instances the condenser is placed in a box on the shaft and revolves
with it. It can be surrounded with the armature coil if preferred. The com-
mutator end of the aforesaid shaft has on it the air blast apparatus, the brush-

page_text: holding levers or yokes, and the rotating commutator. The segments of the
commutator are suitably insulated from the shaft and each other and supported by.
two flanges, one on each side of the commutator. Each segment is mounted upon
supports consisting of rods whose ends are set in insulated holes in the said
flanges; upon these rods are strung connectors, or sleeves to which the segments
are secured by screws. The said flanges are covered with an insulating layer, so
that no conducting surfaces are exposed, and very extended insulation is interposed'
between the segments.
The segments are of copper and rest firmly upon small projections on the
supports. The wires from the shaft or armature terminals are attached to the
supports. To further complete the insulation I cover the shaft under the segments
in some instances with a tube of insulation and sometimes varnish all the exposed
metal except the outer surface of the segments.
In the operation of generators of over 500 volts electro motive force, difficulty is
experienced in carrying out the currents from a single commutator. It is customary
to provide two or more commutators and armature coil systems and to connect
them in series.
This arrangement is objectionable for various reasons.
The simplest manner of applying my air blast is that in which the jets are
supplied with a stream of fluid from any source. The brushes are adjusted so as to
draw a small spark upon which the jet plays. The blast so cools and breaks up
the slight spark that no burning or deterioration of the metal results' and the
segments therefore are only subjected to the wear of attrition diminished by free
oiling. The jet may be sent out from under the slots and revolve with the
commutator. In this case there are three jets corresponding in position to the
slots. In order to avoid the use of an external source of air for the blast I place a'
small blower upon the shaft of the machine. The blower is very advantageously
constructed of a central hub or disc mounted upon the shaft of the machine and
turning with it. The said disc is fitted into the centre of the interior of an oblong
enclosing case which does not revolve, and divides the interior of the said case into
two crescent shaped spaces on opposite sides.
The said disc has three deep radial slots in which three loose wings or pistons
play. During the rapid revolution of the disc the pistons or wings are held out
against the sides of the case by centrifugal force and will tend to carry forward
the air in the spaces in front of them. Openings are made into the case for the
entrance of air, and jets are attached to the discharge openings for draining the
spaces in front of the advancing wings. The jets lead over the face of the com-
mutator-segments. The wings are best made of hard rubber, raw hide, or hard
compressed leather. The disc has such relation to the commutator slots that the
strongest puffs of air are consentaneous with the passage of the slots of the
commutator past the tips of the brushes.
:
Attached to the machine is the regulator magnet for adjusting the position of
the commutator brushes. In the form which I prefer it consists of a U shaped
frame of iron at the centre of the bend of which is fixed a bar of iron surrounded
by a coil of wire through which the generator current flows. The pole of this bar
is shaped to a paraboloidal form as shewn and a movable armature is hung between
the legs on a pivot.
The ends of the armature are placed close to the frame and preserve the same
distance during movement. The armature is perforated by an opening with
rounded edges. The said magnet pole is so formed and adjusted as to possess a
uniform attraction for the armature in any position of the latter within its range,
when a constant current flows through the coil. An arm extends outward from
the armature and is used to magnify the movement of the latter and convey it to
the commutator brushes. A dash-pot or check is provided to prevent sudden
movements of the said armature. A counterpoise whose amount or position may
be adjusted is hung upon the armature lever to overcome any excess of attractive
force of the magnet.

page_text: •
There are two distinct ways of applying brushes to the commutator and attaching
the regulator magnet for controlling the current and in each case all or any, of the
lights or resistances may be removed from the circuit without change of the
generator's speed and without substitution of resistances, a simple movement of
the brushes of the commutator effecting the maintenance of a constant current or
in other words adapting the electro-motive force to the changed resistance of the
circuit.
I call these two cases respectively "forward" and "back" action regulation by
reason of the direction of movement imparted to the commutator brushes in each
case.
In the "forward" action a lever or yoke bears the positive brushes on one side
and the negative brushes on the other side. The interval of their separation is
about 35°. This interval varies with the relative proportions of the machine and
is greater when the field of the machine is relatively less powerful and less with a
very powerful or high field. Assuming the brushes placed in their positions where
the highest electro-motive force is obtained, and it be desired to lower the electro-
motive force, it is only necessary to put the brushes "forward" in the direction of
revolution. This adjustment may be effected by hand but is better accomplished
automatically by the regulator magnet arm coupled to the brush supports. The
adaptation in this case is due to a differential action set up in the armature coils
by the production in a part of the system of counter electro-motive forces.
In the "back action" regulation inovement the brushes on one side are mounted
on separate yokes and set 60° apart for the electro-motive force of maximum
position and to diminish this force to suit changes of resistance of circuit, this angle
is increased gradually by a "backward" movement of two of the brushes and a
simultaneous "forward" movement of the other two brushes at one third to one-
fourth the rate of the others. The lever connections to obtain this result may be
variously arranged. It is essential that at the start the brushes should be set to
those positions of little or no spark. In general the segments break contact with
the forward brush of each pair when the armature coil has nearly reached its
neutral point.
Where it is desired to have the regulator exceedingly prompt and sensitive in its
adjustment, instead of allowing the variations of the general current due to changes
in the resistance of the circuit and the like to act directly by varying the power of
the regulator coil I employ a controller consisting of a sensitive electro-magnet
contact breaker and maker. This controller consists of a coil placed in the circuit
of the machine and lamps surrounding a movable iron core partly sustained by an
adjustable spring. The lifting of the cores is made to open a contact which forms,
when closed, a shunt of small resistance around the regulator coil. To avoid spark
at the contacts a suitable short resistance of carbon or the like is put in circuit
around the contacts. Furthermore, if desired, a copper tube may underlie the
regulator coil and surround its iron core forming a closed circuit around the latter.
The aforesaid spring is so adjusted that the least increase of current will open the
contacts and a decrease will keep them closed. Each action will be accompanied
by a movement of the commutator brushes governed by the said regulator in a
direction to counteract the change.
The electric lamps used in my system are of the two types known as arc and
incandescent and may be used on the same general circuit in series.
In one form of the said arc lamp I use an enclosing iron case or frame through
the centre of which the carbon rod or holder passes vertically. I provide an electro-
magnet consisting of a bar of iron hung from the upper part of the frame and
wound with fine copper wire. One pole of this magnet is curved and is presented
to that of an iron bar or armature pivoted at its other end to the frame. The said
bar is polarized by a surrounding coil of moderately coarse wire in the direct or
arc circuit. The coil of the said magnet is in a derived circuit around the arc
of the lamp. A link is led from the polarized armature to a lever pivoted to a
support on the frame. This lever bears a connection to the lifting clamp or clutch

page_text: which consists of a body provided with a pivoted jaw or cam with an elongation
to which one end of a light spring is affixed which spring acts downwards to close
the cam against the rod. A stop is provided to raise or open the said jaw when
the clamp is lowered. In obedience to the changes of current and are resistance
the clamp will receive movements the result of which will be a gradual feed
lowering or drop of the carbon rod as fast as the carbons are consumed. To render
this action very gradual it is best to have the connections between the lifting
magnet bar and the clamp body possess a slight elasticity or yield.
No dash pot or check is needed in this lamp nechanism and a slow feed of the
carbon is effected. The power of the magnets may be adjusted by altering the
curves of their poles or the distance of the opposed poles apart or the amount of
current or the number of convolutions on each coil.
Should the rod stick or fail to feed from any cause a long flaming are is the
consequence. To prevent this result I establish in the lamp a safety clutch for
ensuring the approach of the carbons.
This clutch acts when a long are exists but not otherwise. It diverts some of
the current to a magnet whose armature when unattracted is a catch or detent
holding a perforated plate clamp from engagement with the carbon rod.
The said magnet is preferably in a shunt or derived circuit of high resistance
around the arc.
The contact is only closed after the first described clamp has been
lowered, the adjustments being made to effect such result. A rod is provided for
elevating the clamp to its original position. A notched plate holds the safety
clutch in a horizontal position when out of action. The contact for conveying
the current to the carbon rod is made as follows. One part is a metal tube.
Passing down into this tube is a small stationary metal rod to the lower end of
which a fine wire brush is attached the wires of which spring out against the
interior of the tube and make contact with it in many places. The main current
is led in by the said small rod
In a modified form of my lamp the fine wire magnet operates a cut out or
shunt of variable resistance around the direct magnet coils which alone control the
clamping devices for feeding the carbons. The core of the magnet closes a series
of contacts successively by which a more or less complete shunting of the current
around the magnet coil is effected. An increase in the power of the derived circuit
magnet coil due to increased arc-resistance will thereby shunt or weaken the
magnet and cause a lowering of its core and the clamp so as to open the latter and
feed the rod as herein before described. The shunting contacts consist of a series
of plates separated by a small interval and electrically connected through small
coils of resisting wire. These plates are successively brought into contact by a
spring on the core when it is drawn into its coil and thus gradually lower the
resistance of the shunt around the said coil.
For feeding two sets of carbon pencils in a single lamp so as to burn one set
before the other I employ simple mechanism for automatic transfer the two carbon
rods are provided with clamps, the prolonged ends of the jaws of each of which
play between stops. The body of the clamps is swung upon an equal armned lever
the centre of which is connected with a bar having an upward and downward
movement given to it by magnets..
Hung upon a central pivot is a lever which can be made to lift either clamp
alternately, there being two upright continuations from the clamps and suitable
stop pins. One end of the said lever is provided with a catch or detent and its
other end is connected with a powerful spring and has a prolongation for
setting it in position. The catch or detent is thrown out by a button on the
rod when the carbons are burnt out and it is desirable that the other set begin
burning.
Instead of using the button for releasing the detent I sometimes use a small
magnet whose attraction opens the catch and if said magnet is controlled by a
shunt or derived circuit around the carbons the transfer of movement will occur

page_text: before the carbons of the first set are completely consumed, as when an abnormal
arc forms accidentally.
My improved low resistance incandescent lamp has a glass envelope with a
cylindrical neck, supported in which is a metal frame, consisting of a ring and
upright wires bent over in an arch at the top; to the centre of the arch is secured
a small block of hard conducting carbon, with a depression for the reception of
one end of a small bar of carbon. The other end is pressed upward by a movable
block of hard carbon attached to a yoke of glass or porcelain movable upon the
side wires of the frame and forced up by a spring. The current is carried in by
pieces of thin platinum foil melted into the neck of the lamp and connected to the
wires leading from the blocks of carbon. The insertion of the lamp in circuit is
made by forming its terminals into a plug and forcing the said plug between the
opposed faces of two plate springs which are the ends of circuit wires leading to
the lamp. When the lamp is removed the springs come together and close the
circuit. A switch is provided to extinguish the lamp or.to modify its intensity by
shunting more or less current around it. Should the carbon rod break or fall out
of place the spring will drive the carbon blocks together and maintain a closed
circuit through the lamp. The lamp is thoroughly exhausted when hot and sealed.
Anhydrous sodium or potassium oxide is left in the vessel and some anhydrous
cupric oxide also exists in it. The lamp is filled with pure dry hyrogen before
exhaustion and any trace of it, or of carbon monoxide or of hydride of carbon are
oxidized by heating the glass where the cupric oxide exists. The carbonic
acid and water, if formed, are taken up with avidity by the sodium oxide leaving
a complete vacuum.
•
The carbon rod for incandescence is made of open porous and rather poor
conducting carbon, afterwards coated with a thin dense layer of hard carbon, by
treatment at a high temperature in an atmosphere of hydrocarbon vapour. This
prevents disintegration from sudden heating and confines the electric current to the
outside of the rod thus preventing overheating of its interior and enhancing the
economy by enabling the incandescence to be obtained from a high surface
temperature. The lamp when worn out may be reorganized by renewing the
carbon and the outer envelope of glass, a new bulb being readily sealed to the
neck containing the conductors.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the
6th January 1883.
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, & Co, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN AND RELATING TO APPARATUS
"2
FOR THE GENERATION, REGULATION AND UTILIZATION OF ELECTRIC CURRENTS
A communication to me from abroad by Elihu Thomson, of New Britain,
Connecticut, United States of America,
'
This invention relates to apparatus for the generation, regulation and utilization
of electric currents and comprises various improvements as hereinafter specified;
Electric generators constructed according to the said invention are composed
essentially of a field magnet or magnets, a revolving armature wound with three
coils or helices of insulated wire connected to form a single three-branched
conductor, a commutator consisting of three insulated removable segments, and
two pairs of diametrically opposite brushes adjustable around the axis of the
commutator; and, in generators of an electromotive force of more than 500 volts,
I use a peculiar air-jet attachment to ensure insulation at the slots between the
commutator-segments; by these means I am enabled to work successfully with
an electromotive force of from 1500 to 3000 volts, if necessary, with one
commutator composed of three segments of about one hundred and twenty degrees
(120°) each, while oil may be freely used as a lubricant for its surface. I also
surround the magnet-poles by a band of good conducting material forming a closed
circuit, for the purpose hereinafter specified. And I employ a triple condenser in
combination with the said segments and armature-coils.
I also provide the generating machine with automatic regulating apparatus
consisting of a peculiar electro-magnetic attachment which adjusts the position of
the brushes around the commutator, so as to regulate the 'strength of the current
according to the resistance, and thus obviate any inconvenience arising from changes
in the resistance of the circuit in which the generator is included.
There are two distinct methods in which the said automatic regulating
apparatus may be employed. According to one of these methods, which I term
"forward action regulation," I obtain the desired result by moving all the brushes
on the commutator forward in the direction of rotation of the armature; according
to the other method, I effect the same result by what I term "back action
regulation" in which one pair of diametrically opposite brushes is moved forward,
while the other pair is moved backward (or in the direction opposite to that of
the rotation of the armature) the rate of movement of the latter pair being about
three or four times as great as that of the first pair.
Each of these methods has its peculiar advantages which adapt it to special
exigencies of working.
I also construct an improved arc-lamp, according to the present invention, which
lump comprises devices for regulating the distance between the two carbons or
electrodes, the upper carbon or electrode being alone adjusted; it also comprises a
very sensitive magnet system composed of a coil through which the direct or arc
current flows and which surrounds a bar of iron movable transversely to the axis
of the said coil, a fixed bar surrounded by a coil of fine wire in a derived circuit
around the arc, and a very sensitive lifting and feeding clamp which effects the
feeding of the carbon-holder in such a manner that the approach of the carbons
when consuming is slow and gradual. I also provide improved means for conveying
the current to the movable carbon-holder as hereinafter described

page_text: The improved lamp is, moreover, provided with a safety device for ensuring the
approach of the carbons when, by accident, an abnormally long arc is formed between
them.
Incandescent lamps, constructed according to the said invention, are of low
resistance and are worked in series, sometimes in circuit with arc-lamps.
The said incandescent lamps have an enclosing globe. of glass exhausted and
sealed and containing.a rod of carbon of peculiar structure, and various appliances
as hereinafter described. In some cases I fill the globe with hydrogen before it is
exhausted and I insert in the said globe a piece or pieces of sodium or potassium
oxide and some anhydrous cupric oxide, for the purpose hereinafter set forth.
'
The said invention is illustrated in the accompanying drawings, in which
Figures 1 and 2 are, respectively, an end elevation and a plan partly in section,
of the improved generator..
Figure 3 is an end view, partly in section, of the armature for the same.
Figure 4 is a diagram shewing the connections of the wires or coils of the
armature.
Figure 5 is a longitudinal central section of another form of armature, and
Figure 6 is an end view of the same.
Figure 7 is a diagram shewing the manner of connecting the coils or helices of
the armature shown in Figures 5 and 6.
• Figures 8 and 9 are, respectively, a side elevation, -and an end view, shewing
another form of armature.
Figure 10 is a diagram shewing the connections of the coils of the same.
Figure 11 is a diagram, and Figure 12 is a side elevation, shewing what I term
a condenser-attachment to the armature-coils.
Figures 13 and 14 are, respectively, a sectional side elevation, and an end
elevation partly in section, shewing details of construction of a commutator
composed of three segments and of an air blast attachment
Figure 15 illustrates the application of an air-jet or blast to the commutator,
and also the connections of the whole system of conductors with the generator.
Figures 16, 17, 18 and 19 are, respectively, a vertical transverse section, an end
view, a horizontal section, and a plan, of an improved blower or device for furnishing
the air-jet or blast, which device is preferably mounted on the shaft of the
generator.
Figures 20 and 21 are, respectively, a side elevation, and an inverted plan, of the
improved regulating apparatus.
Figures 22 and 23 illustrate the two methods of mounting the commutator-
brushes for "forward action" and "back action" regulation.
Figure 24 is a vertical sectional elevation shewing a controlling magnet for
ensuring sensitiveness of action of the regulating apparatus.
Figures 25 and 26 shew, by full and dotted lines, the relative positions occupied by
the commutator-brushes during "forward action" and "back action" regulation.
Figures 27 and 28 are, respectively, a vertical sectional elevation, and a sectional
plan, of an arc-lamp constructed according to the said invention.
Figure 29 is a side elevation of a portion of an arc-lamp of modified
construction.
Figure 30 represents, in front elevation, a device constructed according to the
present invention for feeding two sets of carbons so as to maintain an arc for a
considerable period of time.
Figure 31 is a sectional elevation of an incandescent lamp and its accessories,
constructed according to the said invention.
Figure 32 shews, by longitudinal and transverse sections, the structure of the
carbon rod or pencil used in the same.
In Figures 1 and 2, F, F represent the side supports of the generating machine;
M, M the field-magnet-coils, and B, B iron bars forming a grating around the
machine. X is the shaft, A the armature, and K. the commutator upon which bear

page_text: four brushes C, C2, C3, C. R is the regulating apparatus for moving the commutator-
brushes. The side supports of the machine are provided with bosses F*, F' to
receive the shaft journals. P is the pulley end of the shaft ✗. M¹, M³ are iron
shells surrounded by the wire coils M to form the field-magnets, and enclosing the
spherical armature A between their opposed curved surfaces. B is a small rotary
blower mounted upon the shaft, for furnishing an air-blast to preserve the insulation
of the commutator-segments.
The armature is composed of an iron core consisting of two dished ends or
flanges C (only one of which is shewn, in section); these flanges support bridge-
pieces B³ connecting the said ends and supporting iron wires or bands exterior to
them as shewn, the whole forming an oblate spherical shell; outside of this .shell'
the insulated copper wire is wound. Openings in the shells M' of the field-magnets
allow abundant circulation of air outwards from the armature. The shells M¹ are'
flanged at m to permit their connection with the bars B and the frame F. The
wires from the armature are carried through the shaft to the commutator.
In addition to the magnetizing coils, I sometimes encircle the shells M' with a
band of copper or other good conducting material forming a complete or closed
circuit of low resistance. This device prevents sudden oscillations or fluctuations of
magnetism and, consequently, ensures steadiness of the generated current. The said
bands may be formed of sheet metal, or of wire. Projections are formed on the'
armature core to hold the encircling coils in position. Strong wire bands are also
used for the same purpose. The coils underlie and overlie one another near the
shaft. The connections are shewn in Figure 4, the terminals of the three armature
coils or helices b are joined at a, and the commutator is formed of three segments
to each of which the terminal of one armature-coil is attached. The coils 6 pass
the neutral point in similar positions successively at 120° of rotation apart.
Figures 5 and 6 shew another forin of armature consisting of a ring or hoop
carried by spokes E and having six coils wound upon it. The connections in this
armature are shewn in Figure 7, and are similar to those above described.
Figures 8 and 9 shew another form or modification of the said armature having
six coils wound upon projections f upon a central hub. The armature core is
composed of a number of plates and its coils are connected, as hereinbefore described,
in three sets having three free ends, as shewn in Figure 10.
It will thus be seen that the armature coil system which I employ is simply a
single three-branched conductor, the free end of each branch being connected to
the corresponding commutator-segment.
The generated current is collected by the brushes resting on the commutator.
To diminish the sparks produced at the slots in the commutator, when the brushes
are badly adjusted, I sometimes provide a triple condenser, or condenser having
three opposed foils. These foils are carefully insulated and each foil is connected to
one segment of the commutator. Each foil should have from ten (10) to twenty
(20) square feet of coated surface of average condensing capacity. The action of
this condenser is to obliterate the spark of rupture. In practice, however, if the
commutator-brushes are kept properly adjusted, the spark produced is slight, even
without the condenser, and, when the air-blast attachment herein described is used,
the spark is almost annihilated and the condenser is not required. I may modify,
in various manners, the application of the condenser for absorbing the spark of
rupture, and the modifications will be equivalent in principle to the application
above described.
Figure 11 shews the manner of attaching the terminals of the armature
coils to the triple condenser surfaces; the foils are lettered d', d², ď³.
Figure 12 shews a convenient mode of mounting the condenser. It is placed in
a box on the shaft X and revolves with the same, and may, if preferred, be
surrounded by the armature-coil.
Figure 13 is a view of the commutator end of the shaft X carrying the air-blast
apparatus B³, the brush-holding levers or yokes L', L³, and the rotating
commutator K. The segments of the commutator K are suitably insulated from

page_text: the shaft and from each other, and are supported by two flanges G, one on each
side of the commutator. Each segment is mounted upon a rod r whose ends are
fitted in holes in the flanges G but are insulated therefrom; upon these rods are
placed sleeves to which the segments are secured by screws passing through lugs
extending laterally from the segments, as will be understood by referring to the
end view, Figure 14. The flanges G are covered with a layer of insulating material,
such as hard sheet india-rubber, so that no conducting surfaces are exposed and
very extended insulation is interposed between the segments. Leakage, from
accumulations of grit and dust, is thereby avoided. The segments are of copper
and rest firmly upon small projections on the supports S, and the terminals of the
armature-coils are suitably attached to the said supports.
With this construction, the segments can be removed in a few moments for
cleaning, repairs, or renewal, while an undisturbed surface of copper is presented by
each segment to the action of the commutator-brushes. In some instances, to
ensure good insulation, I cover the shaft under the segments with a tube of
insulating material, and I sometimes varnish all the exposed inetal, except the
outer surface of the segments. I thus obtain a perfect insulation of the segments
sufficient to resist tensions of from 1000 to 2000 volts, or more, without leakage.
In Figure 15 the mode of applying the commutator-brushes, and the circuit
connections through the whole apparatus, are illustrated, the direction of the
current being indicated by arrows. b, b, b represent the armature-coils; K¹, K³,
K³ the commutator-segments; C¹, C the positive brushes which are connected,
and C³, C4 the negative brushes which are also connected; M, M are the field-
magnet-coils, with the working or external resistance, such as lights in the circuit,
between them; there is also shewn in this Figure the application of nozzles J for
supplying jets of air of considerable force directly in front of the tips of the
forward positive and negative brushes and towards the slots in the commutator.
In the operation of generators of over 500 volts electromotive force, difficulty is
experienced in collecting the currents from a single commutator. It is customary
to provide two or more commutators and armature coil systems, and to connect
them in series. This arrangement is objectionable by reason of the multiplication
of parts and the increased liability to derangement through carelessness or
ignorance of the attendant. With a commutator composed of three segments it
would be impracticable to convey a tension of 1000 volts to the cominutator-brushes
without the condenser attachment herein before described, or, more simply, the said
air-jet or blast, as the slots would frequently be crossed by arcs of flame and a
momentary weakening of the generated current would ensue. This action is
termed "flashing over." Moreover, no oil or lubrication is permissible on the
segments of commutators conveying such high tensions. To operate thirty arc
lights in series, a difference of tension of about 1400 volts is required to exist
between the commutator-brushes.
The said Elihu Thomson has discovered that a jet of insulating fluid, such as air,
directed through the slots of a commutator in any direction, at the moment of the
segment leaving the commutator brush, will obviate the difficulties arising from
the use of oil and the tendency to cross or are the said slots, and will preserve the
insulation of the segments; and the said Elihu Thomson has succeeded in
operating with success upwards of thirty arcs requiring about 40 volts tension,
each from a single three-segment commutator, the surfaces of the segments being
at the same time freely lubricated. The simplest manner of applying the air-blast
is that in which the nozzles are supplied with a stream of fluid from any suitable
source, The brushes are adjusted so as to draw a small spark, upon which the jet
plays. One important feature of the said air-blast is, that it so cools, and breaks up,
the slight spark that no burning or deterioration of the metal results, and the
segments, therefore, are only subjected to the wear of attrition diminished by free
oiling. The jets may be arranged in any suitable manner, for example, they may be
directed from under the slots, and the nozzles may revolve with the commutator.
In this case, I employ three jets corresponding in position to the slots, as shown in

page_text: dotted lines in Figure 15. In order to avoid the use of independent apparatus for
the supply of air for the blast, I place a small blower upon the shaft of the machine;
the higher the pressure of the blast, the more perfect will be the effect on very high
tensions, but, for ordinary tensions of from 1000 to 2000 volts, a pressure of one
half pound (lb) to the square inch will suffice, if properly applied.
The nozzles have slits, preferably of a length equal to the width of the segments,
and 0'1 of an inch wide. Any design of blower may be employed with success, if
the jets of air are produced at the moment when the slots are passing the tips of
the brushes. The blower shewn in Figures 16, 17, 18 and 19. is very advanta-
geously constructed of a central hub or disc D mounted upon the shaft X of the
generator and turning therewith. The disc D is fitted in the centre of an oblong
recess or chamber in the case B3 (which is stationary) and divides the said chamber
into two crescent-shaped spaces on opposite sides. The disc D has three deep
radial slots in which three loose wings or pistons h are free to slide. During the
rapid rotation of the disc, the pistons or wings h are held against the sides of the
case B3 by centrifugal force and will tend to carry forward the air in the spaces in
front of them. Openings 1 and 2 are made in the case for the entrance of air, and
nozzles J are attached to the discharge openings for delivering the air from the
spaces in front of the advancing wings. The nozzles J project over the faces of
the commutator-segments. The wings h are preferably made of hard india-rubber,
raw hide, or hard compressed leather. The disc-D is so arranged in relation to the
commutator slots that the strongest jets of air are co-incident with the passage of
the slots of the commutator past the tips of the brushes.
Two nozzles only are sufficient if placed respectively before the positive and
the negative brushes that come last in contact with the segments during the
. rotation of the commutator. The air-blast is applicable to other forms of commu-
tator and may be applied in various manners.
I attach the regulating apparatus, for adjusting the position of the commutator-
brushes, to the generating machine; the form of apparatus which I prefer to employ
is shown in Figures 20 and 21, and consists of a U-shaped frame U of iron, at the
centre of the bend of which is fixed a bar of iron surrounded by a coil of wire to
form a magnet R, through which coil the generated current flows. The pole g of
this magnet is of paraboloidal form as shown, and a movable armature A' is
arranged between the limbs of the frame U and is pivoted at p. The other end of
this armature is in proximity to the frame U and preserves the same distance there-
from during its movement, the parts being suitably shaped for this purpose. The
armature A is formed with an aperture having rounded edges and a diameter
slightly greater than the largest diameter of the pole g of the magnet R. This
magnet-pole is so formed and adjusted as to uniformly attract the armature in any
position of the latter within its range, when a constant current flows through the
magnet coil, and this result I practically obtain with the curves, and within the
range of movement, shewn. An arm & extends outward from the armature A³ and
is used to magnify the movement of the latter and impart movement to the com-
mutator brushes. A dash-pot or check is provided at D³ to prevent too sudden
movements of the armature A³. A counterpoise W, whose weight or position may be
adjusted, is hung upon the lever to overcome any excess of attractive force of the
magnet R.
There are two distinct modes of applying the brushes to the commutator and
attaching the regulator magnet for controlling the current, and in each case all, or
any, of the lights or resistances may be removed from the circuit without changing
the speed of the generator and without substitution of resistances, a simple move-
ment of the brushes of the commutator adapting the electro-motive force to the
changed resistance of the circuit.
"
Figure 22 shews the position of the brushes when "forward action regulation
is employed; the lever or yoke L carries the brushes C¹, C³, on one side, and the
brushes C, C+, on the other side. The interval of separation between C¹ and C³,
and between C³ and _C', is about thirty five degrees (35°). This interval varies

page_text: with the relative proportion of the machine, that is to say, it is greater when the
magnetic field of the machine is relatively less powerful, and less with a very
powerful magnetic field. Assuming the brushes to be shewn in their positions
where the highest electro-motive force is obtained, if it is desired to reduce the
electromotive force to adapt the generator to a diminished external resistance, it is
only necessary to move the brushes forward in the direction of rotation, as indicated
by the arrow. This adjustment may be effected by hand, but is more efficiently
accomplished automatically by the regulator-magnet arm coupled to the brush
supports as shown.
The "back action regulation " will be understood by referring to figure 23.
The positive brushes C, C³, on one side, and the negative brushes C³, C², on the
other side, are mounted on separate yokes and set at an angle of sixty degrees (60°).
apart for the position of maximum electromotive force, and to diminish this
force to suit changes of resistance in the circuit this angle is increased
gradually by a backward movement of the brushes C and C³, and a simul-
taneous forward movement of C¹ and C, at from one-third to one-fourth the
rate of C and C³. The lever connections n, q, to obtain this result, may be
variously arranged; I have shown in Figure 23 one arrangement suitable for the
purpose. The regulator arm is attached, as shewn, to give the movements above
indicated. It is essential that, at the commencement, the brushes should be set to
those positions where little or no spark will be produced; these positions aro
easily determined in obedience to the well known electrical laws. In general, the
segmonts break contact with the forward. brush of each pair, say the positive
brushes, when the armature coil has nearly reached the neutral point.
If it is desired that the regulating apparatus should be exceedingly prompt and
sensitive in its adjustment, instead of allowing the variations of the general
current, due to changes in the resistance of the circuit and other circumstances, to
act directly by varying the power of the regulator magnet R, Figure 20, I employ
controlling apparatus, consisting of a sensitive electro-magnet and a device for
making and breaking contact, to control the admission of current to the coil of
the regulator magnet R. This controlling apparatus is shewn in Figure 24 and
consists of a coil R³ placed in the same circuit as the generating machine and the
lamps, and surrounding a movable iron core A³ partly sustained by an adjustable
spring J. The lifting of the core breaks the contact at t, which contact, when
closed, completes a shunt circuit of small resistance around the regulator magnet R.
To avoid sparking at the contacts a suitable short resistance, of carbon or the like,
as at V, is put in circuit around the contacts t. Furthermore, if desired, a copper
tube may be placed under the coil of the regulator magnet R and form a closed circuit
around its iron core. The energy ordinarily, given out as a spark at the contacts is
transferred to the copper tube as a harmless induced current. The resistance of
the coil of the magnet R should not exceed from one quarter to one half (1/4 to 1/2)
ohm. The spring J is so adjusted that the least increase of current will tend to
open the contacts t, and a decrease will tend to close them or keep them closed.
Each action will be accompanied by a movement of the commutator brushes
governed by the regulator magnet R in a direction to counteract the change. In
practice a constant tremor will occur at the contacts, which will keep the regulator
in its proper position and adjust it for any considerable variations in the strength
of the current.
The relative positions given to the commutator-brushes are represented in
Figures 25 and 26. The full lines, representing the brushes C₁, C, C³, C, Figure 25,
shew the position corresponding to that in Figure 22, while the dotted lines shew
the change in position consequent upon the removal of nearly all the external
resistance during "forward action regulation." The same conditions for "back
action regulation" are similarly represented in Figure 26.
Changes of speed and working resistance, within certain limits, are compensated
by the movement given automatically by the regulator arm ; and generators
constructed according to the said invention, may be put in practical operation to

page_text: run successfully, even when the speed varies from thirty to forty (30 to 40)
per cent.
With the above described system of regulation, in any of its forms, there is no
danger of injury to any part of the apparatus, should there be an accidental short
circuit formed, as no more than the normal current is even then permitted to flow.
Also any light or lights may be switched out of circuit at the lamps without
attention to the generator and with a reduction in the consumption of fuel and of
carbons nearly proportionate to the number of lights extinguished.
Electric lamps of the two types known as arc and incandescent may be used with
the above described system, on the same general circuit, in series. According to the
present invention I construct are lamps as follows, that is to say-In Figure 27,
H represents an enclosing case or frame, through the centre of which the
carbon-holder I passes vertically; e is the upper carbon or electrode and e¹ the lower
carbon or electrode. Y is an electro-magnet consisting of a bar of iron Y' fixed to
the upper part of the frame H and wound with fine copper wire. The curved face
of the pole of this magnet is in proximity to one end of an iron bar or armature T³,
pivotted at its other end to the frame H. The bar T² is polarized by a surrounding
coil T of moderately thick wire in the direct or are circuit. The coil of the
magnet Y is in a derived circuit around the arc of the lamp. The current enters
ata, passes through the coil T, and thence to the upper carbon e, but branches to
the fine wire coil of the magnet Y; the main branch, passing the arc between e and e¹,
leaves at y where it is joined by the fine wire from the magnet Y. A link l
connects the polarized armature T to a lever pivotted at o to a support, as
shewn. The lever is connected to the lifting clamp N. This clamp or clutch
consists of a body N¹ provided with a pivotted jaw or cam N2 with an elongation
to which one end of a light spring S³ is attached; this spring tends to close the cam
against the carbon-holder I. A stop t¹ is provided to raise or open the jaw N'
when the clamp N is lowered. The action of the apparatus is as follows, that is to
say: When no current is passing, the bar T and the clamp are in their lowest
position, the jaw N is open, and the carbons are in contact. On the passage of the
current through the coil T, the bar T is magnetized and oscillates towards Y², thus
lifting the bar 12 and clamp N; the spring S³ closes the jaw N*, the carbon-holder I
is gripped and lifted, and the arc is developed between the carbons e, e¹. The
direction of the current in the magnet coil Ŷ is such as to oppose this action by
polarizing the bar Y* in a direction opposite to the tendency of the bar T to be
drawn toward the magnet Y. In obedience to the changes of current and arc-
resistance, the clamp N will receive movements the result of which will be a gradual
feed or descent of the carbon-holder as the carbons are consumed. To render this
action very gradual it is preferable to give the connections between the bar T and
the clamp-body N' a slight amount of elasticity or yield; and in some cases the
lever is made thin and elastic as indicated at for this purpose. This elastic
portion or elastic support of the clamp N renders the movement of the carbon, in
feeding, very slow and gradual, and is an important feature of the apparatus,
causing great steadiness of light. If properly constructed, no dash-pot or check is
required with this mechanism, and a slow feed of the carbon is effected with great
certainty and regularity. The power of the magnets may be adjusted by altering
either the curves of their poles, or the distance between the opposed poles, or the
amount of current passing through the coils, or the number of convolutions in
each coil.
Should the carbon-holder I stick, or fail to feed, from any cause, a long flaining
arc is the result. To prevent this inconvenience, I provide, in the lamp, a safety-
clutch for ensuring the approach of the carbons in such case. As shewn in the
drawing, this clutch is out of action. It acts when the contact at q is closed by
the return of the bar T, when a long are exists, but not otherwise; the closing of
the said contact diverts some of the current to a magnet Q whose armature forms
a catch or detent, and, when unattracted, holds the perforated clamp or clutch V*
from engagement with the carbon-holder I.
'

page_text: The magnet Q is preferably in a shunt or derived circuit of high resistance
around the arc, which circuit is normally broken at q* during the operation of the
lamp. The contact is only closed after the clamp N has been lowered, the
adjustments being made to effect such result. If the contact at q³ be closed, and
an arc exists at e, e¹, the magnet Q will immediately attract its armature, thereby
releasing the clutch V which will grip the carbon-holder I and be forcibly drawn
down by the spring Z provided for this purpose, thus closing the circuit through
the carbons. A rod and button vare provided for elevating the clamp or clutch V³
to its original position, when necessary, where it is again held by the armature or
detent. A notched plate w holds the clutch V* in a horizontal position when out
of action. The contact for conveying the current to the carbon-holder I is made
as follows, that is to say:-The holder I is a metal tube, the interior surface of
which is made smooth and clean. Passing down into this tube, is a small
stationary metal rod, to the lower end of which a fine wire brush is attached; the
wires of this brush spring out against the interior of the tube I and make contact
with it in many places. The main current enters the carbon-holder through the
said small rod. This is a very effective method of conveying the current to the
carbon-holder, for the reason that the contact surfaces are never fouled by exposure
to dust and oxidation.
The derived circuit magnet and other parts of the lamp are shewn, in plan, in
Figure 28.
A modified form of the improved are lamp is shewn in Figure 29, wherein the
finė wire magnet operates a cut-out or shunt of variable resistance around the
direct magnet coils which alone control the clamping device for feeding the upper
carbon.
The core of the magnet Y closes a series of contacts q³ successively, whereby a
more or less complete shunting of the current around the magnet T is effected.
An increase in the power of the derived circuit magnet Y, due to increased arc
resistance, will thereby shunt, or weaken, the magnet T and cause a lowering of its
core T and the clamp N, so as to release the carbon-holder I and allow it to
descend as herein before described. The shunting contacts q³ consist of a series of
plates separated by small intervals and electrically connected through small coils
of wire of high resistance. These plates are successively brought into contact by
the spring on the core Y* when it is drawn upward, and the resistance of the
shunt around the coil T through the said contacts is thus gradually reduced.
For feeding two sets of carbons or electrodes in a single lamp, so as to burn one
set before the other, I employ simple automatic mechanism as represented in
Figure 30. I, 12 are the two carbon-holders which are provided with clamps N, N³;
the prolonged end of the jaw of each of these clamps is free to move between stops.
The body of each clamp is suspended from a double-armed lever L³, the centre of
which is pivotted to a bar A having upward and downward movements given to
it by magnets. These magnets may be arranged as above described, or other
differential systems may be employed.
Upon a central pivot is another lever D³ which can be made to lift either of the
clamps N, N³ alternately, there being two upright continuations from the clamps,
and suitable stop-pins at ƒ ƒ³. The end of this lever at g' is adapted to be
engaged by a catch or detent h³, and its other end is connected with a powerful
spring Z and has a prolongation for setting it in position. The catch or detent is
thrown out by a button on the carbon-holder I, when the first set of carbons is
consumed and it is desirable that the current should pass through the other set.
In the position of the parts as shewn in this Figure, the detent he holds the lever
D³ in a position to sustain the clamp N³, and the carbon-holder 12, and thus keep
the carbons of the second set separated. Meanwhile the other carbon-holder is
free to be fed by the regulating magnets through the medium of the bar A. In
this position of the parts the end of the lever L³ nearest to I2 is practically
stationary and becomes its fulcrum. If the button on the top of the carbon-
holder I descends into contact with the upper curved face of the detent-lever h³, it

page_text: will force the latter outward and the spring Z³ will immediately depress one end
of the lever D³ and raise the other.end, thus securing the clamp N and releasing
the clamp N for regulation of the second set of carbons. In this case, the end of
the lever Ls next to the carbon-holder I becomes its fulcrum.
Various arrangements may be used for this purpose, for example, instead of
employing the button on the carbon-holder I for releasing the detent, I sometimes
use a small magnet which is adapted to be brought into action by suitable contacts
and whose attraction will release the catch, and, if the said magnet is controlled
by a shunt or derived circuit around the carbons, the transfer of movement will
occur before the carbons of the first set are completely consumed, as, for instance,
when an abnormal arc is accidentally formed. After renewal of the carbons, when
consumed, the lever D³ is again set in its original position and the actions above
described are, repeated.
The great advantage this device possesses over those heretofore employed is, that
a single magnet system is sufficient, while it does not, at any time, require to
sustain or adjust both carbon-holders and their appurtenances. In operation,
therefore, it does not differ from a lamp having only a single set of carbons.
I construct an improved incandescent lamp of low resistance as follows, that is
to say: It is of comparatively small lighting power and is operated by a current
of ordinary strength for an arc-light, say ten (10) ampères. It has a glass envelope
or globe G (Figure 31) with a cylindrical neck, in which is supported a metal
frame consisting of a ring and upright wires 3 bent over in an arch at the top;
to the centre of this arch is secured a small block k of hard carbon with a
depression for the reception of one end of a small rod of carbon specially
prepared as hereinafter described. The other end of this rod is pressed upward by
a movable block k² of hard carbon attached to a yoke of glass or porcelain, movable
upon the side wires of the said frame, and forced upward by a spring 0%.
The current enters by pieces of thin platinum foil cast in the neck of the lamp
and connected to the wires leading from the blocks of carbon k, k². The insortion
of the lamp in the circuit is provided for by making its terminals p³ in the form
of a plug, which plug is adapted to be forced between the opposed faces of two
plate-springs m³ forming the terminals of the circuit wires leading to the lamp.
When the lamp is removed, the springs m³ come together and close the circuit.
The switch t is provided to enable the light to be extinguished, or its intensity
modified, by shunting more or less current around the lamp. Should the carbon
rod break, or fall out of place, the spring O' will move the carbon block k³ into
contact with the block k and maintain a closed circuit through the lamp.
lamp is thoroughly exhausted when hot, and then sealed.
The
·
A small piece, or pieces, of anhydrous sodium or potassium oxide are placed in
the globe or envelope and also some anhydrous cupric oxide. The lamp is filled
with pure dry hydrogen before exhaustion, and any trace of hydrogen, or of
carbon monoxide or of hydrides of carbon, that may remain are oxidized, so as to
form water and carbonic acid, by heating the glass where the cupric oxide exists.
The carbonic acid and water (if any is formed) are taken up with avidity by the
sodium oxide, leaving a complete vacuum.
The carbon rod t, for use as a light-emitting conductor, is made of cylindrical or
other suitable shape, of porous and rather poor conducting carbon, which is
afterwards coated with a thin dense layer of hard carbon, by treatment at a high
tenperature in an atmosphere of hydrocarbon vapor. This formation prevents
disintegration from sudden heating and confines the electric current to the outside
of the rod, thus preventing overbeating of its interior and enhancing the economy
by enabling the incandescence to be obtained by means of a high surface
temperature. When a rod of carbon has a uniform conducting power internally,
there is great danger of volatilization of its centre before the exterior has reached
an economical incandescence. The structure of the said rod is represented in
Figure 32. The lamp, when worn out, may be reorganized by renewing the carbou

page_text: new globe may be readily sealed to
and the outer envelope or globe of glass. A ne
the neck containing the conductors.
Having thus fully described the said invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I Claim:-
First In an electric generator, a band of copper or other good conducting
material forming a closed circuit around the magnet-poles, substantially as
specified.
Second: The method of regulating the strength of electric currents, by moving
'the commutator-brushes forward in the direction of rotation of the armature
by means of automatic regulating apparatus, substantially as above described.
Third: The method of regulating the strength of electric currents by moving
one pair of commutator brushes backward, or in a direction opposite to the direction
of rotation of the armature, and another pair forward at about one-third or one-
fourth the rate of movement of the first pair, substantially as above described.
Fourth-The combination, with a three-segment commutator and a system of
'armature coils constituting a three-branched conductor, of a triple condenser
substantially as described, each foil of which is attached to a segment of the
commutator and to one terminal of an armature coil, substantially as described and
for the purpose set forth.
Fifth The combination, with a three-segment commutator, of two pairs of
commutator-brushes mounted at from thirty to forty degrees apart on an adjustable
yoke, the two positive brushes being united to form one terminal, and the two
negative brushes being united to form the other terminal, as above described.
Sixth: The combination, with a commutator or circuit-changing device, of a jet
or blast of air or insulating fluid directed between the contact surfaces at the
moment of breaking contact with one another, substantially as described, and for
the purpose specified.
Seventh-The combination, with a commutator consisting of insulated segments
separated by open slots, and commutator-brushes applied thereto, of means
whereby a jet of fluid is directed through the slots as they pass the commutator-
brushes.
Eighth―The combination, with the shaft of an electric generator, substantially
as described, of an air-blast attachment and nozzles for directing the blast upon the
commutator.
Ninth An air-blast attachment consisting of a fixed casing and movable interior
wings, whereby jets of air equal in number to the slots in the commutator are pro-
duced, and directed into the said. slots at the moment the latter pass the tips of the
commutator-brushes, substantially as described.
Tenth-In a commutator, metal supports for the segments covered with a layer
of insulating material not in contact with the said segments at any point, the said
segments being supported on a framework, substantially as described.
Eleventh-In a commutator, segments of a ring having laterally projecting lugs,
in combination with a supporting frame and screws for fastening the segments to
the said frame, substantially as described.
Twelfth A commutator consisting of metal segments supported by, or secured
to, open frames, the said frames being in turn supported by, and insulated from,
flanges, upon the shaft, leaving an air-space under, and around, the said segments, and
the said flanges being covered with a layer of insulating material.
Thirteenth-A regulator magnet having a paraboloidal pole and a movable per-
forated, armature therefor, the range of whose movement is limited as described and
which is adapted to be uniformly attracted by the said magnet, under the influence
of a constant current, in various positions of the said armature.
Fourteenth-The combination of a regulator magnet, a movable armature, an
adjustable counterpoise, and a dash-pot, all constructed and arranged as above
described, for the purposes specified.
Fifteenth-The combination of a regulator magnet, such as that above described,

page_text: with the movable, commutator-brushes; all arranged to operate substantially as, and
for the purposes, set forth...
Sixteenth-The combination, with a regulator magnet as described, of a con-
trolling electro-magnet whereby a set of shunting contacts are opened and closed
around the coils of the said regulator magnet, and devices for preventing sparks at
the contacts, substantially as set forth..
Seventeenth-In an electric arc-lamp, a bar of iron, movable transversely to the
axis of a surrounding magnet-coil, and having, opposite one of its poles, a fixed
electro-magnet polarized by a derived circuit current, for the purpose above
specified.
'
Eighteenth-An electric arc-lamp in which the regulating magnet system is com-
posed of a fixed electro-magnet, one pole of which is opposite to the free pole of a bar
movable transversely to the axis of a fixed coil surrounding it, the said bar being
arranged to move the clamp for regulating the position of the carbon or electrode,
substantially as set forth.
Nineteenth-In an electric arc-lamp, a clamp for a carbon-holder, having an
elastic support, or an elastic connection between it and any of its supporting pieces,
substantially as set forth.
Twentieth-In an electric lamp, a safety device consisting of an electro-magnet
brought into action on an abnormal increase of the arc resistance, and a clutch acted
upon by a spring or weight, which clutch is ordinarily held out of action by a catch,
and which, on the removal of the said catch by the attraction of the magnet, is
adapted to grip the carbon-holder and cause the descent of the same, substantially
as described.
Twenty first:-In an electric lamp, a set of contacts directly or indirectly operated
or controlled by the derived circuit magnet, in combination with a safety gripping
clutch and electro-magnetic detent, all arranged to cause a feed of the carbon when
a long arc is formed, substantially as set forth.
Twenty second:-In an electric lamp, a variable resistance cut-out, or shunt around.
the separating and feeding magnet, the said shunt or cut-out being controlled by a
derived circuit magnet, substantially as described.
Twenty third: In an electric lamp, a tubular carbon-holder, in the interior of
which is placed a stationary wire brush carried by a suitable conducting rod for
conveying the current to the interior surface of the said carbon-holder so as to
avoid corrosion and injury to the contact surfaces.
Twenty fourth-In an electric lamp with a double set of carbons and carbon-
holders and lifting clamps or equivalent devices, a bar or lever attached near its..
centre to the magnet system, and at each end to one of the clamps, in combination
with detent or trip mechanisın, such as described, for changing the fulcrum of the
said lever, in the manner, and for the purpose, specified.
Twenty fifth-An electric lamp with two carbon-holders and two clamps for
adjusting the same, and mechanism, substantially such as described, adapted to be
set in position to sustain one of the said clamps and rods in a fixed raised position,
to be released by a tripping detent as described after the consumption of the first
set of carbons, and to subsequently sustain the other of the said clamps in a fixed
raised position and release the first clamp for feeding and regulation, substantially
as set forth,
Twenty sixth-A light-emitting conductor for an electric lanp, the said conductor
having a core of porous and poorly conducting carbon, and a hard thin exterior
coating of good conducting carbon, substantially as described.
Twenty seventh :-In an incandescent lamp, the spring O* which closes the circuit.
through the lamp when the carbon conductor is removed or broken, substantially as
described.
Twenty eighth:-In an incandescent lamp, the combination of the frame inside the
exhausted glass envelope or globe, a sliding yoke on the said frame, the carbon
contact blocks k, k², an interposed carbon light-emitting conductor, and the com-
pressed spring O³, substantially as set forth.

page_text: Twenty ninth: The employment, in an envelope or globe of an incandescent lamp,
which has been filled with pure hydrogen and then exhausted, of pieces of anhydrous
sodium or potasium oxide and oxide of copper, substantially as, and for the purpose,
set forth.
Thirtieth-An incandescent lamp comprising the following parts, that is to say,
a light-emitting conductor of porous poorly conducting carbon coated wholly, or
partially, with hard conducting carbon, two supporting blocks, one of which is
impelled toward the other by a spring for closing the circuit in case of accident, an
enclosing glass envelope or globe filled with dry pure hydrogen and exhausted, and
containing pieces of dry oxide of sodium or potassium and of cupric oxide, all
substantially as, and for the purposes, set forth.
In witness whereof 1 the said William Robert Lake have hereunto set my
hand and seal this Sixth day of January in the year of our Lord One
thousand eight hundred and eighty three.