IMPROVEMENTS IN APPARATUS FOR PRODUCING AND REGU- LATING ELECTRIC CURRENTS, SUCH APPARATUS BEING PARTICULARLY APPLICABLE FOR ELECTRIC LIGHTING
Year: 1873

page_text: LETTERS PATENT to Charles William Siemens, of No. 3, Great
George Street, Westminster, in the County of Middlesex, for the
Invention of "IMPROVEMENTS IN APPARATUS FOR PRODUCING AND REGU-
LATING ELECTRIC CURRENTS, SUCH APPARATUS BEING PARTICULARLY APPLICABLE
FOR ELECTRIC LIGHTING."-A communication from abroad by Dr.
Werner Siemens and Friedrich Von Hefner Alteneck, both of
Berlin, in the German Empire.
PROVISIONAL SPECIFICATION left by the said Charles William
Siemens at the Office of the Commissioners of Patents, with his
Petition, on the 5th June 1873.
I, CHARLES WILLIAM SIEMENS, of No. 3, Great George Street, West-
minster, in the County of Middlesex, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN APPARATUS FOR PRODUCING AND
REGULATING ELECTRIC CURRENTS, SUCH APPARATUS BEING PARTICULARLY APPLICABLE
FOR ELECTRIC LIGHTING," to be as follows:-
This Invention relates to apparatus for producing by mechanical
power currents of electricity, applicable more particularly to the pro-
A

page_text: duction of electric lights, and for regulating automatically the currents
applied to produce such lights.
The improved apparatus for producing the electric currents is of the
following description:-Between the poles or polar extensions of one or
more magnets or electro-magnets is fixed an iron cylinder leaving a
space between its periphery and the faces of the magnetic poles which
are hollowed out to a cylindrical form concentric with the said cylinder.
In this annular space a cylindrical shell of light metal or other material
is caused by mechanical power to revolve round the axis of the cylinder.
On this shell is wound insulated wire in a direction parallel to the axis,
such wire crossing the ends of the shell from the outer periphery
thereof on the one side to the outer periphery on the other side. Thero
may be several such wire coils, each covering an arc of the periphery
on each side of the shell. The ends of the wires constituting each such
coil are connected respectively to pieces of metal, rollers, springs, or
brushes of conducting material which are insulated from one another,
but which in their rotation with the shell and coils bear successively
against two stationary conductors insulated from each other, which con-
stitute the poles of the machine. On causing the shell with its coil to
rotate by mechanical force currents of electricity are generated in the
coils as they successively pass the fixed magnetic poles, and by pro-
perly arranging the conductors from these several coils in relation to the
poles of the magnet, and to the conductors on which they bear in their
rotation, these electric currents are transmitted through any conductor
connecting the poles of the machine. The currents thus transmitted
may be made either continuous or intermittent in one directlon, or they
may be made alternately reversed by suitably arranging the con-
ductors from the several coils in relation to commutators, connecting
them successively during their rotation with the poles of the machine.
The inner iron cylinder may itself be rendered magnetic by coiling on
it longitudinally an insulated electric wire in the manner of what is
known as Siemens' rotating armature, and in this case the outer magnets
might be dispensed with.
Further, the inner iron cylinder instead of being fixed might be made
to rotate, and in this case the separate shell for receiving the wire coils
might be dispensed with, the wire being coiled longitudinally on the
rotating iron cylinder itself. The wire may be coiled on the shell
in two layers over an even number of divisions of the periphery

page_text: The electro-magnets used in the apparatus above described may be
rendered active by electricity from any source, and for this purpose the
electricity produced by the movement of the apparatus itself may be
employed without any extraneous source of electric
power.
In apparatus such as have been described the successive coils have t
to be brought successively into connection with the main circuit by
means of conductors or contact makers, which the ends of their wires
successively pass in their rotation. Such contact makers usually
consist of metallic springs or brushes, or of metallic rollers mounted on
springs, which are pressed against insulated pieces of metal connected
to the wires of the several coils. As these pieces successively pass the
contact maker, when contact is made and broken suddenly, sparks aro
produced, whereby the efficiency of the apparatus is impaired and the
contact parts are gradually wasted.
In order to diminish or entirely avoid the production of such sparks
the insulated pieces of metal connected to the wires of the coils are,
according to the present Invention, made not rigid but elastic, so that
they can yield a little to the spring, brush, or roller, under which they
pass, and thereby remain somewhat longer in contact, or that the one
shall not leave contact before the next has come into contact.
The electric currents produced by apparatus such as have been
described above may be employed for any purpose to which currents of
electricity are ordinarily applied, but they are more particularly
applicable to the production of electric light in electric lamps provided
with automatic regulating apparatus, such as will presently be
described. And as such currents are produced by working the apparatus
by mechanical power, so, conversely, by transmitting electric currents
through the coils of such apparatus the inner cylinder or shell will be
caused to rotate, and thus the apparatus may be employed as an
electro-motor.
In electric lamps, as usually constructed, where the electrical current
is caused to pass through carbon points, the distance of those points is
regulated by clockwork which is influenced by an electro-magnet
placed within the electric circuit, so that the points are caused to
approach when the current is reduced in strength.
According to the present Invention the carbon points of electric
lamps are caused to approach to or recede from one another by the

page_text: action of the electric current itself, entirely or partly without the
intervention of clockwork or other mechanism driven by any extraneous
power; and the regulating apparatus is applicable whether the light bet
produced by alternating reversed currents or by a continuous current
in one direction. For this purpose the lamp is provided with two
electro-magnets, the one of which has a coil of few convolutions of
thick wire in the direct circuit of the current which passes through the
carbon points, offering little resistance to that current. The other
electro-magnet has many convolutions of fine wire in a branch circuit
or shunt from the main circuit, offering considerable resistance to the
passage of a current through the said branch circuit. While the carbon
points are so near each other that the current can pass from the one
to the other with little resistance, the electro-magnet first named is
rendered active, while the second remains comparatively inert, but
when the carbon points are at such distance as to offer a greater
resistance to the current a larger portion of that current has to pass _
through the shunt circuit, and the second magnet therefore becomes
active while the first becomes comparatively inert. Each of these
magnets is provided with an armature which vibrates when its magnet
is active, so as to work a pawl on a ratchet wheel connected to the
stems holding the carbon points by screws or other gearing in such
a manner that when the first magnet is active the carbon points are
gradually withdrawn from one another, but when the second is active
they are made to approach each other. Thus the proximity of the
carbon points is maintained in constant relation to the strength of the
current, which relation is in the first place determined by the adjust-
ment of the armature springs or other portions of the mechanism by
which the armatures are connected to the point holders.
In a modified form of this apparatus, suitable for a continuous
current, one of the magnets may be dispensed with, a weight or spring,
or the weight of the carbon holder itself being used to produce the
movement which that magnet would effect, the magnet which is
retained acting in opposition to this movement when the electric
resistance calls it into play. In such cases the movement effected by
the weight, spring, or weight of the carbon holder may be rendered
slow and gentle by a fly or other suitable resistance, and the opposing
movement of the magnet armature may be rendered independent of
such fly by connecting it through a pawl and ratchet wheel.

page_text: The automatic regulating apparatus, above described, may be applied
to electric lamps worked by currents of electricity produced by
apparatus of any known kind, as well as to those worked by currents
produced as herein-before described.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles William Siemens in the Great Seal Patent
Office on the 4th December 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
WILLIAM SIEMENS, of No. 3, Great George Street, Westminster, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of June, in the year of our
Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for. Herself, Her heirs and successors,
give and grant unto me, the said Charles William Siemens, Her special
license that I, the said Charles William Siemens, my executors, admini-
strators and assigns, or such others as I, the said Charles William Siemens,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
IMPROVEMENTS IN APPARATUS FOR PRODUCING
AND REGULATING ELECTRIC
86
CURRENTS, BUCH APPARATUS BEING PARTICULARLY APPLICABLE FOR ELECTRIC
LIGHTING," a communication to me from abroad by Dr. Werner Siemens
and Friedrich Von Hefner Alteneck, both of Berlin, in the German
Empire, upon the condition (amongst others), that I, the said
Charles William Siemens, my exccutors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.

page_text: NOW KNOW YE, that I, the said Charles William Siemens, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accom-
accompanying Drawings and to the figures and letters marked thereon,
that is to say:-
This Invention relates to apparatus for producing by mechanical
power currents of electricity, applicable more particularly to the pro-
duction of electric lights, and for regulating automatically the currents
applied to produce such lights.
The improved apparatus for producing the electric currents is of the
following description :-Between the poles or polar extensions of one or
more magnets or electro-magnets is fixed an iron cylinder, leaving a
space between its periphery and the faces of the magnetic poles, which
are hollowed out to a cylindrical form concentric with the said cylinder..
In this annular space a cylindrical shell of light metal or other material
is caused by mechanical power to revolve round the axis of the cylinder.
On this shell is wound insulated wire in a direction parallel to the axis,
such wire crossing the ends of the shell from the outer periphery thereof
on the one side to the outer periphery on the other side. There may be
several such wire coils, each covering an arc of the periphery on each
side of the shell. The ends of the wires constituting each such coil are
connected respectively to pieces of metal, rollers, springs, or brushes of
conducting material, which are insulated from one another, but which in
their rotation with the shell and coils bear successively against two
stationary conductors insulated from each other, which constitute the
poles of the machine. On causing the shell with its coils to rotate by
mechanical force currents of electricity are generated in the coils as
they successively pass the fixed magnetic poles, and by properly
arranging the conductors from these several coils in relation to the poles
of the magnet, and to the conductors on which they bear in their
rotation, these electric currents are transmitted through any conductor
connecting the poles of the machine. The currents thus transmitted
may be made either continuous or intermittent in one direction, or they
may be made alternately reversed by suitably arranging the conductors
from the several coils in relation to commutators connecting them
successively during their rotation with the poles of the machine. The
inner iron cylinder may itself be rendered magnetic by coiling on it.

page_text: longitudinally an insulated electric wire in the manner of what is known
as Siemens' rotating armature, and in this case the outer magnets might
be dispensed with.
Further, the inner iron cylinder instead of being fixed, might be
made to rotate, and in this case the separate shell for receiving the wire
coils might be dispensed with, the wire being coiled longitudinally on
the rotating iron cylinder itself. The wire may be coiled on the shell in
two layers over an even number of divisions of the periphery of the
shell, the two opposite divisions in each case having the same wires, but
the ends of those wires being connected successively to insulated con-
ductors in number equal to that of the divisions of the shell, which
conductors revolve with the shell and come successively to bear against
two fixed springs, rollers, or conducting brushes forming the poles of
the machine. The connections of the several wires to these several
conductors may be so arranged that a continuous current is produced by
the rotation of the shell.
The apparatus described above may be modified in the following
manner: Two magnetic poles hollowed out to a cylindrical form are
arranged opposite to each other, and in the centre between them is fixed
a cylinder of iron with a wire coiled in longitudinal slots thereon in the
manner of a Siemens' armature, so that when a current of electricity is
passed through the coil the cylinder becomes magnetic, having its two
sides presented towards the outer magnets of opposite polarity to them
respectively. In the annular space between this central cylinder and
the cylindrical poles outside of it is mounted a cylindrical shell of iron, a
having insulated wire wound round it longitudinally or parallel to its
axis in a number of separate coils, each of which is connected to con-
ductors in the manner described above. This cylindrical iron shell
being caused to rotate by mechanical force between the outer and inner
magnetic poles currents of electricity are caused to pass along the a
wires coiled along it successively as each coil passes through one of the
magnetic fields, and these currents are transmitted either directly or
by commutators as above described to the main poles of the machine.
Instead of employing only two magnetic poles outside the cylindrical
shell, four or a greater even number may be spaced round the circum- 3
ference, and the interior magnet instead of having its wire coiled only
up the one side and down the opposite side, may have it coiled in four

page_text: or a greater even number of recesses in the cylinder upwards and
downwards, so as to give to the inner cylinder as many poles on its
periphery as there are poles outside, each pole of the inner cylinder
being of opposite polarity to the pole presented to it outside. By this
arrangement the successive coils on the cylindrical iron shell are made
to pass in each revolution of the shell through more than two magnetic
fields, and consequently a more rapid succession of currents is generated.
by them.
The electro-magnets used in the apparatus above described may be
rendered active by electricity from any source, and for this purpose the
electricity produced by the movement of the apparatus itself may be
employed without any extraneous source of electric power.
In apparatus such as have been described the successivé coils have to
be brought successively into connection with the main circuit by means of
conductors or contact makers which the ends of their wires successively
pass in their rotation. Such contact makes usually consist of metallic
springs or brushes, or of metallic.rollers mounted on springs which are
pressed against insulated pieces of metal connected to the wires of the
several coils. As these pieces successively pass the contact maker, when
contact is made and broken suddenly, sparks are produced whereby the
efficiency of the apparatus is impaired, and the contact parts are
gradually wasted.
In order to diminish or entirely avoid the production of such sparks,
the insulated pieces of metal connected to the wires of the coils are
according to the present Invention, made not rigid but elastic, so that
they can yield a little to the spring brush or roller under which they
pass, and thereby remain somewhat longer in contact, or that the one
shall not leave contact before the next has come into contact.
The electric currents produced by apparatus such as have been
described above, may be employed for any purpose to which currents of
electricity are ordinarily applied, but they are more particularly appli-
cable to the production of electric light in electric lamps provided with
automatic regulating apparatus, such as will be presently described;
and as such currents are produced by working the apparatus by me-
chanical power; so conversely by transmitting electric currents through
the coils of such apparatus the inner cylinder or shell will be caused to
rotate, and thus the apparatus may be employed as an electro-motor.

page_text: In electric lamps as usually constructed where the electrical current
is caused to pass through carbon points the distance of those points is
regulated by clockwork which is influenced by an electro-magnet placed
within the electric circuit, so that the points are caused to approach when
the current is reduced in strength.
According to the present Invention the carbon points of electric
lamps are caused to approach to or recede from one another by the
action of the electric current itself, entirely or partly without the inter-
vention of clockwork or other mechanism driven by any extraneous
power. And the regulating apparatus is applicable whether the light
be produced by alternating reversed currents, or by a continuous current
in one direction. For this purpose the lamp is provided with two
electro-magnets, the one of which has a coil of few convolutions of thick
wire in the direct circuit of the current which passes through the carbon
points offering little resistance to that current. The other electro-
magnet has many convolutions of fine wire in a branch circuit or shunt
from the main circuit, offering considerable resistance to the passage of
a current through the said branch circuit, while the carbon points are so
near each other that the current can pass from the one to the other with
little resistance, the electro-magnet first named is rendered active while
the second remains comparatively inert. But when the carbon points
are at such distance as to offer a greater resistance to the current a
larger portion of that current has to pass through the shunt circuit, and
the second magnet therefore becomes active while the first becomes com-
paratively inert. Each of these magnets is provided with an armature
which vibrates when its magnet is active, so as to work a pawl on a
ratchet wheel connected to the stems holding the carbon points by
screws or other gearing in such a manner that when the first magnet is
active the carbon points are gradually withdrawn from one another, but
when the second is active they are made to approach each other. Thus
the proximity of the carbon points is maintained in constant relation to
the strength of the current, which relation is in the first place deter-
mined by the adjustment of the armature springs or other portions of
the mechanism by which the armatures are connected to the point
holders.
In a modified form of this apparatus suitable for a continuous current,
one of the magnets may be dispensed with, a weight or spring or the
weight of the carbon holder itself being used to produce the movement

page_text: which that magnet would effect, the magnet which is retained acting in
opposition to this movement when the electric resistance calls it into
play. In such cases the movement effected by the weight, spring, or
weight of the carbon holder may be rendered slow and gentle by a fly or
other suitable resistance, and the opposing movement of the magnet
armature may be rendered independent of such fly by connecting it
through a pawl and ratchet wheel.
Fig. 1, Sheet I., represents a longitudinal section; Fig. 2, a plan;
and Fig. 3 an end elevation of apparatus for producing electric currents
by mechanical power, constructed and operating according to this
Invention.
A, A¹, are a number of bars of iron bent in the middle to a circular
arc, and having their ends coiled with insulated wire, as indicated
at a, a, in such manner that when currents of electricity are transmitted
through these coils the bars A, A¹, are rendered magnetic, and the bent
portions between the coils become fields of opposite polarity, that is to
say, if the upper are A be rendered north the lower are A¹ is at the same
time rendered south. Instead of these bars, magnets or electro-magnets
of any known form having polar extensions, forming circular ares corre-
sponding to A and A¹ may be employed. B is a spindle fixed in a
central position between the magnetic arcs A and A'. On this spindle
is fixed an iron cylinder C, being a tube fitted with end discs c, c, which
are supported on the spindle B. In the annular space between the
cylinder C and the magnetic arcs A, A¹, is mounted a shell or tube 8
supported at each end on discs 8, 8, bored so that they can revolve freely
on the spindle B. One of these discs 8 at the one end is secured by stay
bars p to a pulley P for receiving a band from any convenient motor.
The discs at the other end is secured by stay bars p to an outer disc D,
which as well as the pulley P at the opposite end is provided with a
journal. These journals are mounted in bearings E, E, concentric with
the spindle B, so that when motion is imparted by a band to the pulley P

page_text: the shell S is caused to rotate in the annular space between the cylinder C
and the magnetic arcs A, A¹. On the shell S are wound longitudinally
coils of insulated wire W in such a manner that each wire as it is wound
extends along one side of the shell S, crosses over the end next P, and
returns along the other side of the shell S, the end wires of each coil
being brought through the journal of D and connected to commutating
conductors at F, outside that journal.
Fig. 4, Sheet I., shews diagrammatically an end view of the arrange-
ment of these conductors for wire wound on the shell S over eight equal
divisions of its circumference. The wire to forming the one end of one of
the coils is soldered to a piece of metal m; and the wire w' forming the
other end of the same coil, which returns along the opposite arc of the
shell S, is soldered to another piece of metal m¹. There are two fixed
pieces of metal M, M¹, nearly semicircular, and insulated from one
another, which constitute, or are connected to the electric poles of the
apparatus, and each of the wire terminals m, m³, is brought, as the shell.
rotates, to rub over the poles M, M³, there being always four of these
terminals in contact with each. When the electro-magnets A, A¹, are
rendered active by transmitting an electric current through the coils a, a¹,
on the shell S, with its coils being caused to rotate, electric currents will
be produced in its coils, and such electric currents will be transmitted
from them by their metallic terminals m, m³, making contact successively
with the poles M, M', there will be maintained a current of electricity
available for producing electric light, or for other purposes to which
electric currents are usually applied; and the electric current thus pro-
duced can be transmitted through the coils a, a³, so as to render the
bars A, A¹, magnetic, or these bars can be magnetised by currents
produced from any other source of electricity.
The apparatus so far described may be modified as shewn by a longi-
tudinal section to a smaller scale, Fig. 5, Sheet I. In this case instead a
of employing the fixed iron cylinder C, shewn in Fig. 1 with a shell S,
and its coils W revolving round it, the wire W' is coiled longitudinally
on an iron cylinder C¹, and the whole is caused to rotate within the
magnetic fields A and A', the coil terminals w and w¹ being successively
brought in contact with fixed poles, as already described.
Another modification is shewn in diagrammatic section at Fig. 6,
Sheet I. In this case the fixed inner iron cylinder O is itself rendered
.
.

page_text: magnetic by providing it with longitudinal coils 03 in slots along its
opposite sides, in the manner of that which is known as Siemen's
revolving armature, and transmitting an electric current through these
coils in such manner that the magnetic force in the fields, through
which the coiled shell S revolves, is intensified, each iron face of the
armature being made to have polarity opposite to that of the magnet A
or A¹ which faces it. In this case the wire may be coiled both inside
and outside the shell S₁ longitudinally; and instead of providing only
two such opposite fields four or any even number may be provided, as
shewn diagrammatically with respect to four such fields at Fig. 7,
Sheet I. In this case there are four polar extensions A, A², A³, A³, of
magnets or electro-magnets of alternately opposite polarity hollowed
out circularly, and centrally between them is fixed an iron bar with
four longitudinal chases along it, having electric wire coiled therein
lengthwise, as indicated at C*, C³, C³, C7, such wire being coiled by
leading it backwards along O*, then forwards along Co, backwards again
along C, forwards along C, and so on, thus rendering the iron faces
intermediate to each pair of chases of opposite polarity alternately, such
polarity in each case being opposite to that of the polar extension A or
A1, A2 or A³, which faces it. When this modification is adopted the
connections of the wires coiled on the rotating shell S to the poles
of the apparatus have to be duplicated, so that their respective terminals
instead of making contact with each of the poles M, M', once in every
revolution, as indicated in Fig. 4, shall make such contacts twice in
cach revolution.
When the wires coiled on the shell S or cylinder O¹ are in duplicate,
their connections to their respective terminals m, m³, are arranged as
shewn diagrammatically at Fig. 8, Sheet I., for eight such duplicate coils,
provided with eight terminals marked respectively a, b, c, d, e, f, g, h,
to which the terminal wires of the coils marked respectively 1, 2, 3, &c.,
and 1, 2, 3, &c., are attached. The line of connection may be traced
as follows:-1, f, 4, 4, 9, 61, 6, h, 81, 8, a, 2, 21, 6, 3, 3¹, c, 5, 5¹, d, 7,
7, e, 1 back to 1. When the wires are thus connected their ter-
minals, instead of rubbing on semicircular poles make contact simply
with rollers, brushes, or other conducting points arranged one at each
side of the circle of the terminals.
The Figures on Sheet II. represent to an enlarged scale the improved
contact annaratue whoroby the coil terminale during untation on

page_text: successively into electric communication with the poles so as to avoid
the sparks usually evolved at breaking and making contact.
Fig. 9, Sheet II., is an end view, and Fig. 10 a plan of one form of
this apparatus. The several coil terminals are connected respectively to
a number of springs N forming parts of a cylindrical surface concentric
with the axis of the revolving shell or cylinder. Two metallic rollers
O and O¹, mounted on radii pivotted on insulated frames o, o¹, are
pressed by springs o², o³, against the springs N, so that each of the latter,
as it is brought round by the rotation, makes contact with the rollers
O, O', successively, and these rollers being in electrical connection with
the pinching screws 04, 0%, conducting wires attached by these screws
form parts of the circuit for the electricity generated by the rotation as
described above.
Fig. 11, Sheet II., represents a partial longitudinal section; Fig. 18, a
partial plan; and Figs. 12 and 14, partial end views of the modified
arrangement for the same purpose, wherein the contact springs N,
instead of being arranged round the periphery of a cylinder, as shewn
in Figs. 9 and 10, are arranged radially on the face of a disc, which is
attached to the revolving shell or cylinder, and are by rotation brought
successively in contact with two rollers, one of which is shewn at O,
Fig. 11. According to either of those arrangements the contact springs
N by yielding a little to the pressure of the roller remain for a longer
period in contact with it, so that before one is removed from contact
another comes in contact, and thus sparks are avoided.
Fig. 15, Sheet I., shews diagrammatically an arrangement of the
automatic apparatus for regulating the distance of the carbon points of
an electric lamp worked by alternating currents. a and b are the two
carbon points mounted in an insulated manner in slides on a spindle c,
screwed right and left, so that when this spindle is turned in the ono
direction the points a and b are caused to approach one another, and when
it is turned in the opposite direction they are caused to recede from one
another. On the screwed spindle c is fixed a toothed wheel d, with the
teeth of which either of two pawls e and can engage. These pawls are
attached respectively to the armature levers of two electro-magnets
g and h, which armatures, when the magnets are inert, are drawn away
by springs, but when the magnets are rendered active are attracted in
the direction opposed to the springs. When the armatures are drawn

page_text: back by the springs, the pawls e, f, having inclined faces bearing against
fixed pins are drawn out of gear with the wheel d, but when either
armature is attracted by the magnet to which it belongs its pawl engages
with the teeth of the wheel d and causes that wheel to revolve, the one
pawl e moving it in the one direction so as to separate the carbon
points a, b, and the other pawl fmoving it in the opposite direction so
as to bring these points nearer together. The electro-magnet y has few
coils of large wire in the direct circuit of the electric current to the
carbon point a or b. The other magnet h has many coils of fine wire, so
as to offer considerable resistance, and its coils are in a shunt or byc-
circuit from the main circuit as indicated by the dotted lines shewing
the electrical connections. While the electric current passes through
the points a, b, producing the light, the magnet h remains inert, but the
magnet is active and its pawl vibrating in obedience to the magnetic
force and spring moves the wheel d and screwed spindle c so as to
separate the points a, b. As the points a, b, attain such a degree of
separation as to furnish resistance in the main circuit approaching to
that in the shunt the magnet h becomes active, and the pawl f
operated by it turns the wheel d so as to cause the carbon points to
approach each other. Thus the distance of those points is automatically
regulated to a determined electric arc.
In the modified apparatus shewn diagrammatically at Fig. 16, Sheet I.,
for an electric lamp worked by a continuous current the armature levers
of the pawls e, f, have contacts e¹, f¹, so arranged that when the arma-
ture is moved by the attraction of the magnet it makes contact at the
point e' or f¹ so as to throw its own coil out of circuit, and to make a
short circuit through the carbon points, thus releasing itself from the
attraction by rendering its magnet inert. In other respects the reciprocal
action of the two magnets on the carbon points is as described above in
reference to Fig. 15.
One of the electro-magnets with its pawls may be dispensed with by
an arrangement such as is shewn diagrammatically at Fig. 17, Sheet I.,
the weight of the stem carrying one of the carbon points, being
employed as the force for making the carbon points approach each
other, while the electro-magnet is employed to make them recede from
each other. In this case the stems and supporting the carbon
points a, b, are toothed as racks, the one k gearing into a pinion, and
into a smaller pinion on the same axis, so that as k descends ascends,

page_text: between
but more slowly. Thus the points a, b, would tend by the action of the
greater weight of k to approach one another, while the space
the carbon points would also descend, but more slowly. As however
one of the carbon points become wasted more rapidly than the other, the
position of the flame would nevertheless be maintained in the desired
focus. On the same spindle with the pinions is a toothed wheel m
gearing with a pinion on the spindle of a wheel n which by a ratchet
drives a fly q, this wheel being moved in the opposite direction by the
pawle of the one electro-magnet without driving the fly. The armature
lever of the pawle is arranged as in Fig. 16 to break and make contact
for its own coil according as it is attracted or not. By this arrangement
the weight of the one stem acts with a velocity regulated by the fly q to
bring the carbon points nearer together while the pawle worked by the
electro-magnet acts so as to make the carbon points separate from one
another, the two forces counteracting each other in such manner as to
maintain the points at a distance apart equivalent to a determined
electric arc. It may be readily understood that instead of employing the
weight of the stem k to move the points nearer to one another, another
weight or a spring might be used.
Having thus described the nature of this Invention and in what
manner the same is to be performed, as communicated to me from my
foreign correspondents, I claim,--
.
First. The use of apparatus for producing electric currents by the
application of mechanical force, in which apparatus a shell coiled
longitudinally with insulated conducting wires on its outside is made to a
revolve in the annular space between fixed external magnetic poles or
polar extensions and a fixed internal cylinder of iron which may be
independently magnetised, substantially as herein described.
Second. The use of apparatus of the kind above referred to in which
the wire instead of being coiled along a shell is coiled longitudinally 3
over the external surface of an iron cylinder which is made to revolve
within magnetic poles or polar extensions, substantially as herein
described.
Third. In apparatus such as is above referred to the use of a rotating
shell coiled both externally and internally in combination with fixed 3
external and internal magnets, substantially as herein described.

page_text: Fourth. The method substantially as herein described in reference to
Figs. 4 and 8, Sheet I., of coiling the wires of the shell of apparatus such
as is referred to above, whether such wires are single or in duplicate, and
of connecting them to the poles of the apparatus.
Fifth. The use in apparatus such as is referred to above of spring
terminals for the wires of the coils, arranged cylindrically or radially so
as to be brought by rotation successively in contact with spring rollers,
substantially in the manner and for the purpose herein set forth.
Sixth. The use for automatically regulating the distance of the carbon
points of electric lamps, of two electro-magnets working a wheel in
opposite directions by means of pawls, such magnets being rendered
active or inert according as the electrical resistance varies, substantially
as herein described in reference to Figs. 15 and 16, Sheet I.
Seventh. The use for automatically regulating the distance of the
carbon points of electric lamps of one electro-magnet working by a pawl,
a wheel in opposition to a weight or spring, the said magnet being
rendered active or inert according as the electrical resistance varies,
substantially as herein described in reference to Fig. 17, Sheet I.
In witness whereof, I, the said Charles William Siemens, have
hereunto set my hand and seal, this Second day of December,
in the year of our Lord One thousand eight hundred and seventy-
three.