IMPROVEMENTS IN APPARATUS FOR PRODUCING THE ELECTRIC LIGHT, PARTS OF WHICH INVENTION ARE APPLICABLE TO OTHER PURPOSES
Year: 1876

page_text: LETTERS PATENT to Samuel Alfred Varley, of Hatfield, in the County of
Hertford, Telegraphic Engineer, for the Invention of "IMPROVEMENTS IN
APPARATUS FOR PRODUCING THE ELECTRIC LIGHT, PARTS OF WHICH INVENTION
ARE APPLICABLE TO OTHER PURPOSES."
PROVISIONAL SPECIFICATION left by the said Samuel Alfred Varley at the
Office of the Commissioners of Patents on the 19th December 1876.
SAMUEL ALFRED VARLEY, of Hatfield, in the County of Hertford, Telegraphic
Engineer. "IMPROVEMENTS IN APPARATUS FOR PRODUCING THE ELECTRIC LIGHT,
PARTS OF WHICH INVENTION ARE APPLICABLE TO OTHER PURPOSES."
This Invention is an improvement on previous Inventions, for which Provisional.
Protection was granted to myself in conjunction with Cornelius Varley, bearing
date the 24th day of December, 1866, No. 3394, but which was not proceeded with
and which was continued by a new application, and for which Letters Patent were
granted, bearing date the 15th day of June 1867, No. 1755.
In the before-mentioned Provisional Specification a method was described which
may be said to have marked a new era in the construction of dynamo-electric
machines used for producing the electric light.
Nearly all the subsequent machines which have been designed for this purpose
depending for their action on the principle first described in the Provisional Specifi-
cation before referred to, which consisted in making electricity and magnetism
developed by the expenditure of mechanical force to act and react on one another in
the machine itself in such way as to develop a greatly increased amount of both
these forces, the consumption of force giving motion to the machine increasing
and having relation to the increased amount of magnetism and electricity produced.
The nature of my present improvement will be rendered inore clear by a brief
reference to the machine described in the Provisional Specification herein-before
referred to, No. 3394, 1866.
The machine therein described consisted of a number of soft iron cores or bobbins
wrapped with insulated wire and mounted on an axle, by means of which they
were revolved, and to which was attached a reversing commutator; these bobbins

page_text: revolved between opposite poles of soft iron magnets which were also wrapped with
insulated wire. The soft iron magnets were so arranged that they presented north
and south poles alternately and opposite to one another, and the bobbins when
revolved were magnetized first in one direction, and then in the other, positive and
negative electric currents being developed in the insulated wire of the bobbins
alternately at each reversal of the magnetic polarity.
The commutator closed the electrical circuit through the insulated wire of the
bobbins and the soft iron magnets, the electricity passing round the soft iron
magnets in the direction to increase their magnetic polarity, which increased polarity
reacted upon the bobbins, developing an increased amount of electricity.
Just previous to the reversal of the magnetic polarity the commutator connected
the ends of the insulated wires both of the magnets and the bobbins together, and
immediately afterwards the commutator reversed the ends of the insulated convolu-
tions of the bobbins relatively to those of the soft iron magnets, and put them again
in circuit with one another, so that the electricity now produced by the reversal of
the magnetic polarity of the bobbins passed relatively to the magnets the same way
as before, and maintained their polarity always in one direction.
The capability of the machine just described and of all others of this class is
limited to a considerable extent, from the fact that the force consumed in giving
motion to the machine is being converted into magnetism and electricity at the
same time not only is the magnetism produced less proportionately as electricity is
being developed, but force is also wasted.
The electricity produced when the magnetic polarity is reversed neutralises and
lowers the magnetic potential of the bobbins; the consequence of this is, when the
next reversal takes place and the magnetic potential previously acquired becomes
converted into electrical force, the electricity produced is less than it would have
been had the magnetic potential just previous to the reversal been higher.
My improvement consists in separating the developement of the electrical and
magnetic forces to a considerable extent, obtaining thereby a greatly increased
magnetic potential in the bobbins, which at a later stage becomes converted into
clectricity of a correspondingly high potential. I effect this by what may be
described as splitting up the bobbins. I divide the bobbins into groups, each group
having nearly the same relation to the soft iron magnets as one bobbin in my
previous Invention; in other words the alternations of north and south poles between
which the bobbins revolve correspond to the number of groups and not to the actual
number of bobbins, so that if the machine has 6 groups of bobbins, and each group
consists of 3 bobbins, there will be 6 pairs of soft iron magnets presenting alternate
north and south poles instead of eighteen, as would have been the case in my
former Invention.
The number of bobbins in each group may be 2, 3, 4, or more, the number of
commutators employed may correspond to the number of bobbins forming a group,
or they may be increased in number, and when electricity of a very high potential
is desired the commutators may be increased to the same number as the bobbins.
I now proceed to describe what takes place in one of my improved machines
when set in motion, and which for simplicity of description I will suppose to consist
of two pairs of soft iron magnets only and two groups of bobbins, each group con-
sisting of three bobbins.
The first or advancing bobbin of the group when its magnetism is reversed by
passing from between the poles of the magnets into those of opposite polarity
developes electricity throughout the circuit after passing onward a certain
determined distance; when all or the greater part of the electricity has been
developed this bobbin is by the action of the commutator cut out of the circuit, and
receives magnetism only. A little further on the connections relatively to the
electrical circuit are reversed, and this bobbin is then again thrown into the circuit.
The polarity of the second and following bobbins is now reversed, and the electricity
developed thereby passes through the insulated wire of the first bobbin which is
now included in the electrical circuit, and raises its magnetic potential to a very

page_text: high degree. The first bobbin now passes between the magnetic poles of the
opposite polarity, and the high magnetic potential previously acquired developes a
corresponding equivalent of electricity. In the same way as the electricity developed
in the second bobbin raises the inagnetic potential of the first one, so does the
electricity developed in cach following bobbin raise the magnetic potential of the
one preceding it.
What I have just described as taking place in the bobbins of one group is also
taking place at the same time in the second group, the only difference being that
the electricity developed in the bobbins of the one is opposite to that which is being
developed in the corresponding bobbins of the other. The insulated wires of the
bobbins of the two groups are however so connected that the electricity developed
in both flows round the soft iron magnets, and through the electrical circuit in tho
same direction.
By my improved arrangement just described, not only do I obtain a higher
magnetic and consequently a higher electrical potential than could be obtained from
my former Inventions, but as the reversal of the bobbin connections takes place
when they are receiving magnetism only and before the reversal of their magnetic
polarity, the whole of the electricity which is produced at the time of the reversal
passes through the electrical circuit.
In my previous Invention herein-before referred to, and in all machines of this
class, a certain amount of loss occurs both of the magnetic and clectrical forces when
the insulated wires of the magnets and the bobbins are short circuited, just previous
to the reversal of the magnetic polarity of the bobbins, and during the time the
reversal of the connections is being made.
I now proceed to describe the construction of the commutator of a machine
having three bobbins to each group.
The ends of the insulated wires of the bobbins are connected to metal discs
mounted on the axle of the machine, but electrically insulated from it and also from
one another. There are usually three dises to each commutator, two of these dises
being employed for changing the connections, and one for cutting out the bobbins
from the electric circuit.
When the number of commutators correspond to the number of bobbins forming
a group, the ends of the insulated wire of the bobbins of each of the groups are
joined side by side and connected to their respective discs of the commutators;
for example, if the machine consists of six groups, then the ends of the insulated
wire of the leading bobbins of each of the groups are joined side by side and con-
nected to one cominutator. The ends of the second and following bobbins of each
of the groups are joined in the same way together and connected to the second
commutator, and the third and last bobbin of each of the groups are connected to
one another and to the third commutator.
The springs which rest against the said commutators are so connected as to form a
continuous electrical circuit from one to the other through the metal discs of the
commutators.
The changing of the connections and the cutting out the bobbins from the electri-
cal circuit at regular intervals is effected by dividing or cutting away portions of
the discs, the number of divisions having relation to the number of groups in the
machine, or in other words, to the number of changes in the connoctions which
have to be made in each revolution.
The inward motion of the springs which press against the periphery of the com-
mutators is limited by stops of insulating material so as to prevent the springs
following and making contact with the metal discs when a spaco or a division is
opposite to the springs.
By cutting away at regular intervals more or less of the metal discs all the
necessary adjustments for reversing and cutting out the bobbins from the electrical
circuit at determined positions can be effected.
The object of the commutator is simply to make the necessary changes in
the connections at regular intervals, and its construction admits of modification.

page_text: The iron cores or bobbins may be made of soft iron and split on one side
to prevent the development of electric currents in the body of the iron, or they may
be made of a bundle of iron wires, or of sheet iron rolled up upon itself.
In some cases, to provent more completely the developement of electricity at
those periods when I desire magnetism only to be produced, I wrap the bobbins
with two insulated wires in the reverse direction, and at the time when the bobbins
are cut out of the electrical circuit by a modification in the construction of the
commutator, the ends of the two insulated wires are connected together for
a short interval, the effect of which is to more completely neutralize the develop-
ment of electricity.
Part of the electricity developed by the machine is diverted to maintain the
magnetism of the soft iron magnets, and the remaining portion is used to produce
the electric light; there are several well-known ways of doing this, but the method
I prefer is, to wrap the soft iron magnets with two insulated wires, one having a
larger resistance than the other. The circuit of larger resistance is always closed,
and the circuit of less resistance is used for the electric light.
When the electric light is being produced the greater portion of electricity passes
through the circuit of less resistance, which 1 tern the " electric light circuit,"
maintaining the inagnetismn of the magnets, and producing the light; when the
electric light circuit is open from any cause, the electricity developed passes through
the circuit of greater resistance only, and maintains the magnetism of the magnets.
The electric light is produced by closing the "electric light circuit" through a
carbon rod which rests on the periphery of a disc of carbon, usually bevelled on the
edge; this disc may be made of what is termed "gas carbon," and which is de-
posited on the side of the retorts in the process of making coal gas, or they may be
inade of what is technically termed "moulded carbon."
Motion is given to the carbon disc, the carbon rod rests loosely on the disc, and
the contact being imperfect, the electric circuit is completed by an electric arc being
formed, and a similar effect is produced as when carbon conductors are brought into
contact and separated a short distanco from one another.
In some cases I construct the carbon disc of segmental pieces of carbon, sepa-
rating each seginent with a suitable non-conducting substance, an electric arc is
then formed when the carbon rod is passing over the space occupied by the non-
conducting material.
When a solid carbon disc is used a slight joggling action may be communicated
to the carbon rod by any of the well-known methods to insure actual separation.
Two carbon rods may also be employed instead of one, the circuit being completed
through the one to the carbon disc, and through it to the second carbon rod.
I prefer to give rotation to the carbon disc by means of the electric force generated
by the machine itself, and so avoid having to depend upon more or less complicated
mechanism which has to be wound up.
I communicate motion in the following way :-Hollow helices of insulated wire
are arranged end to end, each helix being separated by a space from one another.
In these spaces iron discs, mounted on a soft iron spindle (which passes through the
helices and runs in suitable bearings) move.
The iron discs are divided into teeth on their outer periphery, and the helices are
encased with iron tubes or shells, divided at both ends into teeth, corresponding in
number with those cut in the iron discs.
The insulated wire composing the helices is connected to the insulated wire sur-
rounding the soft iron magnets of the machine, and is usually inserted in the circuit
of Greater Resistance.
When the machine is set in motion the soft iron cylinder in the centre of the
helices becomes powerfully magnetic, and the teeth of the discs and those of the
shells mutually attract one another, giving motion to the iron discs. There is a
commutator attached to the soft iron cylinder, which closes and opens the electric
circuit through the helices in succession, and the discs are arranged so that their
teeth break joints one with the other.

page_text: When the machine is in action the helix in the electric circuit renders the portion
of the iron cylinder enclosed by it magnetic, and the teeth of the iron discs are
attracted by the teeth of the iron shell covering this helix; when the teeth of the
disc, moved by magnetic attraction, are almost opposite the teeth of the shell, the
commutator closes the electric circuit through the 2nd helix and opens it with
respect to the one previously polarized; the discs are now moved another step for-
ward. In this way, with a suitable number of helices and divided discs, the
electric circuit being closed and opened through the helices in succession, a rotary
motion is given to the cylinder which gives motion to the carbon disc.
The helices are wrapped with two wires joined together at one end and insulated
at the other. These wires are wrapped in opposite directions. The electricity which
gives motion to the discs passes through one of these wires only, say, for dis-
tinction, No. "1," No. "2" being disconnected at one end the commutator
just before it opens the circuit of the helix electrically polarised connects the end of
No. "2" to No. "1."
The secondary or extra current, as it is sometimes termed, which is generated
when the circuit is opened, now passes into No. "2," which is wrapped in the
opposite direction to No. "1," and the demagnetization of the part of the iron
cylinder previously magnetized is very rapidly effected in consequence.
In order to ascertain the amount of electric force which is being produced at any
time, I attach to the machine an electric guage which I construct in the following
way I wrap a hollow bobbin, which may be made of brass, with a number of
convolutions of soft iron wire; in the centre of this a permanent magnet is mounted
in pivots, care being taken that the pivot holes are placed truly in the centre so
that the poles of the magnet may be as nearly as possible at an equal distance from
the iron wire, whatever position the magnet may be in. Circular or segmental
coils, usually made of insulated copper ribbon, are mounted above and below the
poles of the magnet, allowing space sufficient for the magnets to pass freely
between.
An index or pointer, moving over a divided scale, is connected by a spring to the
upper pivot of the magnet, and retains the magnet in the centre of the circular
coils when the machine is not in action.
The circular coils are placed in the electric light circuit, and when the machine is
in action the magnet is deflected. The index is then turned round until the tension
of the spring is sufficient to bring the magnets back again into the centre of the
coils. The distance travelled by the index to effect this indicates the amount of
electric force which is being developed.
Malleable cast iron may be used for the magnets in place of soft iron. Common
cast iron may also be used, and permanent magnets may in some cases be sub-
stituted with advantage for the soft iron magnets, but the coercitive force or the
power of permanent magnets to resist depolarization is limited, and the develop-
ment of electricity when the machine is in motion drives back the magnetism, tem-
porarily depolarizing them to some extent, and consequently renders them less
effective. To neutralize this effect when I use permanent magnets I prefer to arm
them with soft iron poles which I wrap with insulated wire. The electricity de-
veloped by the machine is made to pass through this insulated wire and developes
sufficient magnetism to neutralize the depolarizing effect before referred to.
Those parts of my Invention by which the electricity which produces the light
is developed are applicable for nearly all purposes where electricity in large
quantities is required.
The high electrical potential which can be readily obtained by my Invention.
renders it, for example, very suitable for the production of ozone as well as other
purposes where electrical currents of high tension are wanted.
The electric guage used in my said Invention, and the method of obtaining
rotary motion, are also applicable to electric currents obtained by chemical action or
Thermo Electric sources.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Samuel Alfred Varley in the Great Seal Patent Office on the 19th
June 1877.
SAMUEL ALFRED VARLEY, of Hatfield, in the County of Hertford, Telegraphic
Engineer. "IMPROVEMENTS IN APPARATUS FOR PRODUCING THE ELECTRIC LIGHT,
PARTS OF WHICH INVENTION ARE APPLICABLE TO OTHER PURPOSES."
This Invention is an improvement on a previous Invention for which provisional
protection was granted to myself, in conjunction with Cornelius Varley, bearing
date the 24th day of December, 1866, No. 3394, but which was not proceeded with,
and which Invention was made the subject of a second application, and which Letters
Patent were granted to us, bearing date the 15th day of June, 1867, No. 1755.
In the before-mentioned provisional specification a method was described which
may be said to have marked a new era in the construction of dynamo-electric
machines used for producing the electric light.
Nearly all the subsequent machines which have been designed for this purpose
depend for their action on the principle first described in the provisional specification
above referred to. This principle, as set forth in the said specification, consists in
causing electricity and magnetism developed by the expenditure of mechanical
force to act and re-act on one another in the machine itself in such a way as to
develope a greatly increased amount of both these forces. Such increased amount of
magnetism and electricity, as is well understood, involves an increase in the con-
sumption of mechanical force for giving motion to the machine.
The nature of my present improvement will be rendered more clear by a brief
reference to the machine described in the provisional specification herein-before
referred to, No. 3394.
The machine therein described consisted of a number of soft iron cores or bobbins
wrapped with insulated wire and mounted on an axle, by means of which they were
revolved, and to which was attached a reversing commutator; these bobbins revolved
between opposite poles of soft iron magnets, which were also wrapped with insulated
wire. The soft iron magnets were so arranged that they presented north and south
poles alternately, and opposite to one another, and the bobbins when revolved wero
magnetized first in one direction and then in the other, positive and negative electric
currents being developed in the insulated wires of the bobbins alternately at each
reversal of the magnetic polarity.
The commutator closed the electrical circuit through the insulated wire of the
bobbins and the soft iron magnets, the electricity passing round the magnets in the
direction to increase their magnetic polarity, which increased polarity reacted upon
the bobbins, developing an increased amount of electricity.
Just previous to the reversal of the magnetic polarity the commutator connected
the ends of the insulated wires both of the magnets and the bobbins together, and
immediately afterwards the commutator reversed the ends of the insulated con-
volutions of the bobbins relatively to those of the soft iron magnets, and put them
again in circuit with one another, so that the electricity now produced by tho
reversal of the magnetic polarity of the bobbins passed relatively to the magnets
the same way as before, and maintained their polarity always in one direction.
The capability of the machine just described, and of others of its class, as here-
tofore constructed, is limited to a considerable extent, because the force consumed
in giving motion to the machine is being converted into magnetism and electricity
at the same time, and the magnetism produced is less proportionately as electricity
is developed.
The electricity produced when the magnetic polarity is reversed partially
neutralizes the magnetism of the bobbins; the consequence of this is that when
the next reversal takes place, and the magnetism previously acquired thus becomes
converted into electrical force, the electricity produced is less than it would have
been had the magnetism been greater just previous to the reversal.

page_text: My improvement consists in separating the development of the electrical and
magnetic forces to a considerable extent, obtaining thereby greatly increased magnetic
potential in the bobbins, which at a later stage becomes converted into electricity of
a correspondingly high potential. I effect this by what may be described as
'splitting up" the bobbins, that is to say, I divide the bobbins into groups, each
group having nearly the same relation to the soft iron magnets as one bobbin had
to the soft iron magnets in my previous machine, that is, in a machine according to
the former Invention above referred to. In other words, the alternations of north
and south poles, between which the bobbins revolve, correspond in my improved
machine to the number of groups, and not as in my old machine to the actual
number of bobbins, so that, if the machine has six groups of bobbins, and each group
consists of three bobbins, there will be six pairs of soft iron magnets presenting
alternate north and south polos, instead of eighteen, as would have been the case in
my old machine.
The number of bobbins in each group may be 2, 3, 4, or more, the number of
commutators employed may correspond to the number of bobbins forming a
group, or they may be increased in number, and when electricity of a very high
potential is desired the commutators may be increased to the same number as tho
bobbins.
I now proceed to describe what takes place in one of my improved machines
when set in motion, and which, for simplicity of description, I will suppose to consist
of two pairs of soft iron magnets only and two groups of bobbins, each group consisting
of three bobbins.
The first or advancing bobbin of the group, when its magnetism is reversed by
passing from between the poles of the magnets into those of opposite polarity,
developes electricity throughout the circuit after passing onward a certain determined
distance, when all or the greater part of the electricity has been developed this bobbin
is by the action of the commutator cut out of the circuit and receives magnetism only.
A little further on, the connections relatively to the electrical circuit are reversed
and this bobbin is then again thrown into the circuit. The electricity developed in
the bobbin of the group whose magnetic polarity is next reversed passes through
the insulated wire of the first bobbin, and raises its magnetic potential to a very
high degree. The first bobbin then passes between the magnetic poles of the
opposite polarity, and the high magnetic potential previously acquired developes a
corresponding equivalent of electricity and raises the magnetic potential of the
bobbin following it. In this way the magnetic potential of each of the bobbins is
raised to a high degree just before the reversal of its polarity takes place.
What I have just described as taking place in the bobbins of one group is also
taking place at the same time in the other group, the only difference being that the
electricity developed in the bobbins of the one group is opposite to that which is
being developed in the corresponding bobbins of the other. The insulated wires of
the bobbins of the two groups are however so connected that the electricity
developed in both flows round the soft iron magnets and through the electrical
circuit in the same direction.
By my improved arrangement just described not only do I obtain a higher
magnetic and consequently a higher electrical potential than could be obtained in
my old machine, but as the reversal of the bobbin connections takes place when
they are receiving magnetism only, and before the reversal of their magnetic
polarity, the whole of the electricity which is produced at the time of the reversal
passes through the clectrical circuit."
Although for simplicity of description I have above referred to the use of only
two groups of bobbins, in practice three or more groups may be used with advantage,
the number depending upon the requirements of each particular application.
In my old machine herein-before referred to, and in other machines of this class,
a certain amount of loss occurs, both of the magnetic and electrical forces, when the
insulated wires of the magnets and the bobbins are short circuited, just previous to

page_text: the reversal of the magnetic polarity of the bobbins, and during the time the
reversal of the connections is being made.
I now proceed to describe the construction of the commutators of a machine
having three bobbins to each group.
The ends of the insulated wires of the bobbins are connected to metal discs
mounted on the axle of the machine, but electrically insulated from it, and also
from one another. There may be three discs to each commutator, two of these discs
being employed for changing the connections, and one for cutting out the bobbins
from the electrical circuit.
When the number of commutators corresponds to the number of bobbins forming
a group, the ends of the insulated wires of the bobbins of each of the groups are
joined, side by side, and connected to their respective discs of the commutators; for
example, if the machine consists of six groups then the ends of the insulated wires of
the leading bobbins of each of the groups may be joined, side by side, and connected
to one commutator. The ends of the second and following bobbins of each of the
groups may be joined in the same way together and connected to the second com-
mutator, and the third and last bobbin of each of the groups may be connected to
one another and to the third commutator.
The springs which rest against the commutators are so connected as to form a
continuous electrical circuit, from one to the other, through the metal discs of the
commutators.
The changing of the connections and the cutting out the bobbins from the
electrical circuit at regular intervals is effected by dividing or cutting away portions
of the discs, the number of divisions having relation to the number of changes
which have to be made in the connections during each revolution.
The inward motion of the springs which press against the peripheries of the
commutators is limited by stops of insulating material, so as to prevent the springs
following and making contact with the metal discs when a space or a division is
opposite to the springs.
By cutting away, at regular intervals, more or less of the metal discs, all the
necessary adjustments for reversing and cutting out the bobbius from the electrical
circuit at determined positions can be effected.
The object of the commutator is simply to make the necessary changes in the
connections at regular intervals, and its construction admits of modification.
The iron cores or bobbins may be made of soft iron and split on one side, to
prevent the development of electric currents in the body of the iron, or they may
be made of bundles of iron wires, or of sheet iron rolled up upon itself.
Part of the electricity developed by the machine is diverted to maintain the
magnetism of the soft iron magnets, and the remaining portion is used to produco
the electric light. There are several well-known ways of doing this, but the method
I prefer is to wrap the soft iron magnets with two insulated wires, one having a
larger resistance than the other. The circuit of larger resistance is always closed
and the circuit of less resistance is used for the electric light.
When the electric light is being produced the greater portion of electricity passes
through the circuit of less resistance which I term the "electric 'light circuit,"
maintaining the magnetism of the magnets and producing the light. When the
electric light circuit is opened from any cause the electricity developed passes
through the circuit of greater resistance only, and maintains the magnetism of the
magnets.
"
The electric light is produced by closing the "clectric light circuit" through a
carbon rod which rests on the periphery of a disc of carbon, usually bevelled on the
edge.. This disc may be made of what is termed gas carbon," and which is
deposited on the sides of the retorts in the process of making coal gas, or they may
be made of what is technically termed "moulded carbon."
Motion is given to the carbon disc. The carbon rod rests loosely on the disc,
making imperfect contact, and the electric circuit is completed by the formation of

page_text: an electric arc, a similar effect being produced as when carbon conductors are
brought into contact and separated a short distance one from another.
In some cases I construct the carbon disc of segmental pieces of carbon, separating
each segment with a suitable non-conducting substance, an electric arc is then
formed when the carbon rod is passing over the space occupied by the non-conducting
material.
When a solid carbon disc is used a slight joggling action may be communicated
to the carbon rod by any of the well-known methods to ensure actual separation.
Two carbon rods may also be employed instead of one, the circuit being completed
through the one to the carbon disc and through it to the second carbon rod.
I prefer to give rotation to the carbon disc by means of the electric force generated
by the machine itself, and so avoid having to depend upon more or less complicated
inechanism which has to be wound up.
I communicate motion in the following way-Hollow helices of insulated wire
are arranged end to end, each helix being separated by a space from its neighbours.
In these spaces move iron discs, which are mounted on a soft iron spindle that
passes through the helices and runs in suitable bearings.
The iron discs are formed with teeth on their outer peripheries and the helices
are encased with iron tubes or shells formed at both ends with teeth, corresponding
in number with those on the iron discs.
The insulated wire composing the helices is connected to the insulated wire
surrounding the soft iron inagnets of the machine, and is usually inserted in the
circuit of greater resistance.
When the machine is set in motion the soft iron cylinders in the centres of the
helices become powerfully magnetic, and the teeth of the discs and those of the
shells mutually attract one another, giving motion to the iron discs. There are
commutators which close and open the clectric circuit through the helices in
succession, and the discs are arranged so that their teeth "break joint" or alternate
one with the other, as herein-after described.
When the machine is in action the helix in the electric circuit renders the portion'
of the iron cylinder enclosed by it magnetic, and the teeth of the iron discs are
attracted by the teeth of the iron shell covering this helix. When the teeth of the
discs, moved by magnetic attraction, are almost opposite the teeth of the shell a
coinmutator closes the electric circuit through the second helix and opens it with
respect to the one previously polarized; the discs are now moved another step
forward. In this way, with a suitable number of helices and divided discs, the
electric circuit being closed and opened through the helices in succession, a rotary
motion is given to the cylinder which gives motion to the carbon disc.
Each of the helices is wrapped with two wires joined together at one end and
insulated at the other. These wires are wrapped in opposite directions. The
electricity which gives motion to the discs passes through one of these wires only,
say, for distinction, "No. 1," the other ("No. 2") being disconnected at one end.
The commutators just before they open the circuit of the helix electrically polarized
connect the end of "No. 2" to the end of "No. 1."
The secondary current or "extra current," as it is sometimes termed, which is
generated when the circuit is opened, now passes into "No. 2," which is wrapped in
the opposite direction to "No. 1," and the demagnetization of the part of the iron
cylinder previously magnetized is very rapidly effected in consequence.
In order to ascertain the amount of electric force which is being produced at any
time, I attach to the machine an electric gauge which I construct in the following
way I wrap a hollow bobbin which may be made of brass with a number of
convolutions of soft iron wire; in the centre of this a permanent magnet is mounted
on pivots, care being taken that the pivot holes are placed truly in the centre so
that the poles of the magnet may be as nearly as possible at an equal distance from
the iron wire, whatever. position the magnet may be in. Circular or segmental
coils, usually made of insulated copper ribbon, are mounted above and below the

page_text: Figs. 20 to 25 shew the construction of the apparatus for giving motion to the
carbon disc used for producing the electric light.
Fig. 26 is a sectional view of the electric gauge and Fig. 27 is a top view of the
same with parts removed to shew the construction more clearly.
A, A, (Figs. 1 and 2) are two uprights usually made of gun metal or other suitable
non-magnetic substance, to which are attached the iron blocks B, more clearly shewn
in Figs. 2 and 3, and which form extensions of the poles of the electro-magnets. C
are the electro-magnets attached to the iron blocks B. D is an axle which carries
the bobbins E', E², E³, F¹, F², F³, G², G², G³, H², H³, H³. I is a pulley_attached to
the axle, by means of which motion is communicated to the machine. I* is a pulley
revolving loosely on the axle, on to which the band is shifted when it is desired to
stop the machine. J, J, are bearings in which the axle runs. K is a cradle in which
the bobbins lie; this cradle is attached to the axle, and the bobbins are kept in
their places by lashing them together by a cord or in any other suitable way. L
are the commutators attached to but electrically insulated from the axle. M, M*,
are contact springs, which rest on the commutator discs. When the machines are
constructed with a large number of bobbins in each group the extensions of the
magnetic poles B, as shown in Figs. 13 and 14, may be made of continuous circles
instead of segmental pieces of iron, as the loss of magnetism arising from the
opposite magnetic poles being connected by a bridge of iron is in such cases com-
paratively small.
•
The way in which the commutators are connected together is shewn in Fig. 17
(Sheet 3), which represents the commutators of a machine having two groups of
bobbins and three bobbins in each group. The arrangement consists of nine metal
discs, divided into three sets, electrically connected together, as indicated by the
dotted diagonal lines; portions of the discs are cut away, as shewn in Fig. 18, which
is an end view of one set. L*, L', are discs connected to the ends of the insulated
wires of the bobbins. L² are the discs through which the circuit is completed when
the bobbins are receiving magnetism only. M and M* are the contact springs
which press against the metallic discs of the commutators. L³, L, are metallic discs
mounted on, but insulated from the axle D, against which contact springs M rest;
these are connected to a divided metallic ring L, L, which is mounted on the axle
but insulated from it; an end view of this divided ring is shewn in Fig. 19; when
electricity in one direction only is required the circuit is closed through the
dotted lines M², M*; when alternate positive and negative currents are desired the
circuit is closed through M*1, M*3.
In Fig. 2 the bobbins E, F, G, H, are passing from between the magnetic poles
of one name into those of opposite polarity, and are developing electricity. I term
this position of the bobbins " No. 1 position;" the bobbins E, F, G, H², are dis-
connected from the electrical circuit, and are acquiring magnetism or magnetic
potential only. I term this "No. 2" position. The bobbins E, F, G, H³, are in
what I term "No. 3" position, that is, the position where they are again put into
the electrical circuit, the ends of the insulated wires of the bobbins relative to the
general circuit being however reversed to what they were when in "No. 1" position
The electricity developed in the insulated wires of the bobbins in "No. 1 "
position passes through the bobbins in "No. 3" position, through the insulated wire
of the electro-magnets, and through the whole of the electrical circuit, magnetizing
the electro-magnets, and increasing the magnetic potential of all the bobbins in
"No. 3" positions. The next reversal takes place during the passage of the bobbins
from "No. 3" position to the succeeding "No. 1" position, the bobbins in "No. 2"
position passing on to "No. 3" position, and having their magnetic potential raised, as
before described, by the bobbins which are now passing on to "No. 1" position. In
this way the magnetic potential of each of the bobbins in its passage from " No. 2"
position onwards until just before it reaches the succeeding "No. 1" position is raised
to a high degree, and the magnetic potential thus acquired becomes converted into
electricity during the passage of the bobbin into "No. 1" position, and onwards until
it reaches "No. position.
33

page_text: •
To avoid confusion the connections between the magnets, bobbins, and commu-
tators are indicated only generally in the Drawings, but their arrangement will be
readily understood by electricians from the description given, aided by reference to
Figs. 174, which are theoretical diagrams, showing each of the bobbins of a single
group in the three positions herein-before referred to as "No. 1," "No. 2," and
« No. 3."
N (Figs. 20 and 21) is a carbon disc mounted on the axle O, to which are attached
the soft iron cylinders P, with discs or flanges Px divided into teeth on their outer
peripheries. The iron cylinders revolve in the helices of insulated wire Q; pare
soft iron shells surrounding the helices Q; the faces of these shells are divided into
teeth corresponding to those of the iron discs P*; q are helices of insulated wire,
.which are usually placed over the iron shells to further increase the development of
magnetism.
The diagramatic view, Fig: 22, shews the alternate positions of the teeth of the
iron discs and shells. R, R¹, are the commutator wheels electrically insulated from
one another, and also. from the axle; the teeth of these wheels "break joint " one
with the other, that is to say, the teeth of one wheel are opposite the spaces between
the teeth of the other wheel, as shewn in Fig. 21. These wheels alternately close
the circuit through the helices when the axle is rotated.
are the
demagnetising commutators, each of which is composed of two divided wheels, the
teeth of which "break joint" with one another, the teeth of the one wheel being
opposite the spaces between the teeth of the other wheel, as indicated in Fig. 21.
These wheels are insulated from the axle and from one another. S, Sx, S¹, S², S*, S',
are contact springs; S*, S3, are in electrical contact with each other, S and Sare
also electrically connected; S* is in permanent electrical contact with R, and S¹ is
always in contact with R. One end of the two insulated wires of which each
helix Q,, is composed is connected with the axle; the other ends of what I have
termed for distinction the "No. 1" wires of the two helices are connected to R and
R, and the other ends of the "No. 2" wires are connected to r¹, The electrical
circuit is closed through the contact springs S, S, and the current passes from the
axle through the helices alternately, and out at S, or vice versa.
The circuit is represented in Fig. 20 as closed through the "No. 1" wire of the
helix connected to the commutator wheel R, and the Nos. "1" and "2" wires of
the helix connected to R¹ are represented as connected together by the deinagnetizing
commutator 72.
In Fig. 20 the rotatory apparatus is represented as constructed with two hollow
.helices and revolving cylinders, but it will work better if constructed with three or
more helices.
T, Fig. 23, is a carbon rod attached to the lever U, and resting by gravity on the
carbon block N.
The dotted lines V, V, Fig. 20, represent the convolutions of iron wire of the
electrical gauge, which insulate the magnets inside from external magnetisın. W
are the circular coils. X are the magnets working over the surfaces of and between
the coils. X* is an axle to which the magnets are attached. Y¹ is a torsion spring,
one end of which is attached to the axle X*, and the other end to the circle Z,
whose surface has degrees marked on it. Z¹ is a handle, by means of which the
circle Z can be turned round. Y' is a pointer attached to the axle Xx, and which is
deflected when the circuit is closed through the coils of the electrical gauge. Y* is
a fixed pointer, which shews the number of degrees the divided circle Z has been
moved in bringing back the pointer Y¹ to zero, and which measures the amount of
force exerted by the current on the magnets.
The dotted lines and circles, Fig. 27, shew how the electrical gauge can be rendered
much more sensitive to electric currents by increasing the number of coils and
magnets, as indicated by the dotted lines.
Having described the nature of my said Invention, and explained the mode of
-carrying the same into practical effect, I desire to have it understood that save and
except as lierein-after mentioned I do not intend to claim any of the mechanical or

page_text: electrical parts of the apparatus herein-before shewn and described when taken
separately and apart from the combination or application thereof in manner and for
the purposes herein-before described, but what I consider to be novel and original
and therefore claim as secured to me by the herein-before in part recited Letters
Patent is,―
First. The method herein-above described of obtaining a high degree of" magnetic
potential" in the bobbins by causing the insulated wires of the bobbins at certain
determined positions to be cut out of and disconnected from the electric circuit, and
whilst so disconnected to acquire magnetisın only, and further increasing such
magnetism by causing electricity developed in other parts of the machine to pass
through the insulated wires of the said bobbins after they have been again put into
the electric circuit, but before their magnetic polarity is reversed, the high " magnetic
potential "so acquired being converted into electricity at the next reversal of the
magnetic polarity of the said bobbins, as described.
Secondly. The method herein-before described of obtaining rotary motion by the
use of iron discs provided with teeth in conjunction with iron shells or tubes, also
provided with teeth, the said discs being attached to or forming parts of iron
cylinders, which are mounted on a common axle, and revolve in helices of insulated
wire, which helices by means of commutators are rendered alternately active and
inactive, and magnetize in succession the enclosed iron cylinders and shells, the said
cylinders and shells being rapidly demagnetized in the manner described.
In witness whereof, I, the said Samuel Alfred Varley, have hereunto set my
hand and seal, this Nineteenth day of June, in the year of our Lord One
thousand eight hundred and seventy-seven.
S. ALFRED VARLEY. (L.S.)