IMPROVEMENTS IN THE UTILIZATION OF ELECTRICITY FOR LIGHT, HEAT, AND POWER, BEING AN IMPROVED SYSTEM AND MEANS FOR THE GENERATION, REGULATION, DISTRIBUTION, MEASUREMENT, AND TRANSLATION OF ELECTRICITY LIGHT, HEAT, OR POWER
Year: 1880

page_text: LETTERS PATENT to Thomas Alva Edison, of Menlo Park, in the State of
New Jersey, United States of America, for an Invention of "IMPROVEMENTS
IN THE UTILIZATION OF ELECTRICITY FOR LIGHT, HEAT, AND POWER, BEING
AN IMPROVED SYSTEM AND MEANS FOR THE GENERATION, REGULATION,
DISTRIBUTION, MEASUREMENT, AND TRANSLATION OF ELECTRICITY
LIGHT, HEAT, OR POWER."
INTO
PROVISIONAL SPECIFICATION left by the said Thomas Alva Edison at the
Office of the Commissioners of Patents on the 11th February 1880.
THOMAS ALVA EDISON, of Menlo Park, in the State of New Jersey, United States
of America. "IMPROVEMENTS IN THE UTILIZATION OF ELECTRICITY FOR LIGHT,
HEAT, AND POWER, BEING AN IMPROVED SYSTEM AND MEANS FOR THE GENERATION,
REGULATION, DISTRIBUTION, MEASUREMENT, AND TRANSLATION OF ELECTRICITY
INTO LIGHT, HEAT, OR POWER."
The object of this Invention is to so arrange a system for the generation, supply,
and consumption for either light, heat, or power, or either or all, of electricity that
all the operations connected therewith requiring especial care, attention, or know-
ledge of the art shall be performed for many consumers at stations, leaving the
consumer only the work of turning off or on the supply, as may be desired; in other
words to so contrive means and methods that electricity may be supplied for
consumption in a manner analogous to the system for the supply of gas and water,
without requiring any greater care or technical knowledge on the part of the
consumer than does the use of gas or water, in order that economy, reliability,
and safety may be insured.
In carrying the Invention into effect a city, town, village, or locality may form
one district, or if the extent of territory makes it desirable may be divided into
Beveral districts.
In each district I provide a central station, at which are grouped a suitable prime
motor or several motors, dependent upon the amount to be supplied, generators
or means for converting the prime motive power into electricity, means for
determining and regulating the amount of electricity generated and supplied, in
order that a constant pressure of electricity (so to speak) may be kept up.
The prime motors are any suitable engines, steam or water, and one or a series
of two or more are provided as may be necessary, each of which is provided with

page_text: its own system of shafting and belting driving a number of magneto electric
machines, the number actuated by one prime motor being hereinafter termed a
battery.
It is to be noted, as is also shown in previous applications for Patents made by
me, that I make my field of force magnets exceedingly long, and of an extremely
large mass of metal in proportion to the mass of metal in the revolving armature
carrying the generating coil. By this extra length, as the magnetic tension
at the poles increases with their distance apart, there is secured at the polar
extensions acting upon the coils in the field of force a much greater magnetic
intensity, or so to speak, a greater motive force or pressure, causing consequently
the generation of a greater amount of energy in the coils operated on than would
result from the use of shorter magnets, even though the same mass of metal were
used therein. By this elongation of the cores I am enabled to dispense with
numerous convolutions or layers, one layer of wire being sufficient, whereby the
resistance of the machine is largely diminished. The large mass of metal in these
magnets is magnetically saturated by a weak current passing around them. It
takes this weak current a long time to bring this mass of metal up to the point of
practical maxiinum magnetic intensity, but once brought to that point the weak
current readily keeps them there, while with a shorter inagnet a stronger current
would more speedily magnetically saturate them; this stronger current would still
be required to keep them so saturated.
If the coils of the field of force magnets and the generating coils were included
in one circuit, and all the currents generated were passed through the field magnet
coils, a very much greater amount of current than necessary for the maintainance
of a practical magnetic maximum in the field of force magnets would be passed
around them, and the coils acting as resistances to the energy in excess of that
required to magnetise the magnet to its practical maximum would cause a great
waste of electric energy; hence I prefer to keep the field of force magnets and the
generating coils separate, and that one machine in each battery (which machine
may be termed the battery field of force generator) be used to supply the requisite
energy to the field of force magnets of the other machines in such battery (which
may be termed the supply generators).
The coils of the field of force magnets are connected as a series in a multiple arc
in one circuit, while the generating coils of the supply generators of each battery
are all connected in a multiple arc to the main conductors (though for special
purposes they may be connected as a series).
This will give great economy, as the per cent. of the entire current generated in
each battery absorbed in keeping up the magnetic maximum in the field of force
magnets, when it is furnished by one special machine of the battery, the number
given it to feed being properly calculated, being less than when a portion of the
current generated in each machine is absorbed in its own field of force magnets.
Where a single battery of machines is used it is preferable, in view of what has
been herein before stated, that the current for the coils of the field of force magnets
of the field of force generators of the battery be supplied by a small galvanic
battery, but if more than one battery of machines be used the field of force
generators of all the batteries are fed from one or more prime field of force
generators connected in a multiple arc or in a series, the field of force magnets of
the prime field of force generator or generators used being kept magnetically
saturated by a weak galvanic battery current, as before set forth. For instance,
a weak galvanic current supplies the field current necessary for one prime field of
force generator, which in turn feeds the field of force magnets of the field of force
generators of ten batteries of twenty or thirty machines, the ultimate effect in the
generation of currents depending upon (as one important factor) the tension of the
galvanic current sent through the field of force coils of the prime field of force
generators.
This prime field of force generator may however be a dynamo electric machine

page_text: instead of a magneto machine, its field of force being kept up by the current
generated in the machine instead of by a galvanic current.
At the central station all the supply generating coils or batteries thereof are
connected to conductors on the multiple arc system, and from these conductors at
the station main conductors (which for convenience may be called simply the
mains), connected thereto on the multiple arc system, lead in any and all desired
directions, conveying the energy to the points where work either by translation
into light or motive power is to be done.
In order to give a better understanding of the method of regulating what for
convenience may be called the pressure of the current through the entire system,
I will here state that all the devices for the transmission of electricity into work
are arranged on the multiple arc system, each device being in its own derived
circuit, the effect being in substance to give each a circuit from the generating
source independent of the circuit of all the other devices; as a resultant it follows.
that the greater the number of transmitting devices brought into circuit, the less
the total resistance of the current.
For instance, I prefer my lamps should be of about 100 ohms. resistance, then if
one lamp only be in circuit there is a resistance of 100 ohms.; if another lamp be
put in circuit, two circuits of 100 ohms. are provided for the current, making the
net total resistance to the current 50 ohms.
Although the resistance in each derived circuit remain unchanged, this effect is
ordinarily opposite to the effect produced by the addition of lamps when they are
connected in an ordinary straight circuit, each one then adding to the resistance of
the circuit. The bringing into operation successively of numbers of the devices,
and thereby making more paths or circuits for the currents, does not appreciably
lessen the pressure or diminish the effect upon the devices in use, the active force
at the central station, viz., prime field of force generators and motive power,
remaining unchanged until the net resistance of the devices in circuit exterior to
the battery of machines is so diminished as to approach in a degree the resistance
of the battery and main conductors, it being remembered that as the machines of
a battery are connected in multiple arc the net internal resistance of a battery is
as many times less than one as there are machines in the battery.
To avoid any appreciable variations and insure uniformity it is essential that
any lessening of pressure be immediately indicated, in order that just sufficient
energy be generated and sent out to keep up an equal flow through the circuit of
each translating device, that is, that the pressure be kept up uniform whether
more or less translating devices be in circuit.
This is obtained by providing at the central stations means for constantly
indicating the pressure and for regulating the production of appreciable variation
be indicated at each station test lights are arranged, so that an approximate
visual test of the effect of pressure upon the circuit of any translating devices in
use may be shown.
From what has been said it is evident that as more or less translating devices
are brought into circuit the total resistance of the circuit, or all the circuits thereof,
to the flow of all the current generated varies. To indicate this electrodynamo-
meters, galvanometers, or electrometers are placed across the main conductors at
the central station, or by return wire at any point in the circuit, with a zero mark
placed to correspond with the deflection consequent upon the maintenance of the
proper amount of pressure.
It may be advisable (and I have so done) to place at the central station a series
of standard "Daniell's" batteries, connected by a switch circuit to the galvanometer
or dynamo galvanometer, in order that they may be frequently tested for any
inaccuracy occurring from any cause whatever. By these means any error what-
ever therein is readily detected.
To correct variations in the pressure various means may be employed. Each
supply generator may be connected into the circuit through a switch, and each
series may be likewise so connected, so that the current of one or more of a series,

page_text: or one or more entire series, may be cut out or thrown into the circuit; or each
machine may be arranged so as to be disconnected from the prime motor, or when
needed the prime motor of an entire series may be disconnected.
The plan I prefer however is to arrange in connection with the circuit of the
battery feeding the field of force magnets of the prime field of force generator before
referred to, a series of resistances so that the energy of the battery current may be
varied, this variation causing in turn a variation in current induced in prime field
of force generator, and in all the generators directly or indirectly controlled thereby.
When a dynamo machine is used these resistances are to be used in same manner
in connection with the circuit including the coils around the field magnets.
For distributing the current thus generated and regulated at the central station,
I prefer to use conductors within insulated pipes or tubing made water tight and
buried in the earth, provision being made at suitable intervals for house or side
connections.
While this plan is preferable for many reasons it is evident that conductors may
be carried in the air or over house tops. While only one pair of conductors may be
laid on each street, I prefer, especially where streets are wide, to lay a pair of
conductors along each side of the street near the curb. At proper intervals street
lamps may be connected thereto by derived circuits.
From main conductors on principal streets subsiduary main conductors are laid
through side streets; from the street conductors, wherever desired, derived circuits
are led into the houses, one of the conductors passing through a suitable meter,
preferably one which measures the amount of electricity passing through, as set
forth in my Patent, No. 4226, of October 23, 1878.
In the house each translating device is placed in a derived circuit, the entire
system of means for generation, conduction, and translation being one great
multiple arc system. The translating device in each house may be either for light
or power, or both. For light, the electric lamp consisting of an incandescing
material hermetically sealed in glass is preferred.
This lamp is made of high resistance in comparison with that of any electric:
lamps which to my knowledge have been proposed. In lights heretofore proposed
the endeavour seems to have been to lessen the resistance of the carbon, none
having been suggested of higher resistance than, say, 10 ohms., but I have discovered
a very much higher resistance, say, 100 ohms., must be used in order that a number
may be economically and successfully used in a system.
The motor used should be so constructed that each with a constant flow or
pressure of current will give the exact power required.
This requires that each motor should be wound with finer or coarser wire, and
with more or less convolutions which determine the maximum effect of the motor.
In addition, as the motors may be run with variable loads or amount of work to
perform, and as irregularity of speed would be a consequent thereof, it is preferable
to provide each motor with a governor, which on excessive speed would operate to
break the circuit of the motor or otherwise control it. A preferable form of
governor, therefore, will form the subject matter of an application for Patent to be
filed by me.
A system arranged as thus described provides for all the conditions precedent to
an economical and reliable utilization of electricity as a lighting or motive power
agent.
As within certain ascertainable limits the greater the horse power of an engine
the less the proportionate cost per horse power, by consolidating at one station the
prime motive force necessary to the generation of a supply for many consumers, a
great economy as to production occurs.
As ordinarily proposed, each electric light requires its own regulator, which
usually is either thermostatic or magnetic, breaking the circuit or bringing in
resistances, in any case making a cumbrous lamp requiring delicate management
and constant attention.
By regulating at the central station entirely I am enabled to use a small separate
4

page_text: lamp, which may be used with the exercise of no more than ordinary care or
attention.
The distribution is so provided for that tampering therewith is guarded against,
and that connections from the mains to localities of translation are readily made.
The means for measuring insures accurateness, and in furnishing a basis for
equitable charges for the amount used by one particular consumer.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Alva Edison in the Great Seal Patent Office on the 11th
August 1880.
THOMAS ALVA EDISON, of Menlo Park, in the State of New Jersey, United States
of America. "IMPROVEMENTS IN THE UTILIZATION OF ELECTRICITY FOR LIGHT,
HEAT, AND POWER, BEING AN IMPROVED SYSTEM AND MEANS FOR THE GENERATION,
REGULATION, DISTRIBUTION, MEASUREMENT, AND TRANSLATION OF ELECTRICITY
INTO LIGHT, HEAT, OR POWER."
The object of this Invention is to so arrange a system for the generation, supply,
and consumption for either light or power, or both, of electricity that all the
operations connected therewith requiring special care, attention, or knowledge of
the art shall be performed for many consumers at central stations, leaving the
consumer only the work of turning off or on the supply, as may be desired; in
other words, to so contrive means and methods that electricity may be supplied for
consumption in a manner analogous to the system for the supply of gas and water,
without requiring any greater care or technical knowledge on the part of the
consumer than does the use of gas or water, in order that economy, reliability, and
safety may be ensured.
In carrying the Invention into effect a city, town, village, or locality may form
one district, or if the extent of territory makes it desirable may be divided into
several districts. In each district I provide a central station, at which are grouped
a suitable prime motor or several motors, dependent upon the amount to be supplied,
generators or means for converting the prime motive force into electricity, means
for determining the amount of electricity generated and supplied, in order that a
constant pressure of electricity (so to speak) may be kept up. The prime motors
are any suitable engines, steam or water, and one or a series of two or more are
provided as may be necessary, each of which is provided with its own system of
shafting and belting driving a number of magneto electric machines, the number
actuated by one prime motor being hereinafter termed a battery. It is to be noted
that I make my field of force magnets exceedingly long and of an extremely large
mass of metal in proportion to the mass of metal in the revolving armature carrying
the generating coil. By this extra length, as the magnetic tension at the poles
increases with their distance apart, there is secured at the polar extensions acting
upon the coils in the revolving armature a much greater magnetic intensity, or so

page_text: to speak a greater magneto motive force or pressure, causing consequently the
generation of a greater amount of energy in the coils operated on than would result
from the use of shorter magnets, even though the same mass of metal were used
therein. By this elongation of the cores I am enabled to dispense with a number
of layers of coils, as one layer of wire is usually sufficient, whereby the resistance of
the machine is largely diminished. The large mass of these magnet cores is
magnetically saturated by a weak current passing around them. It takes this
weak current a long time to bring this mass of metal up to the point of practical
maximum magnetic intensity, but once brought to that point the weak current
readily keeps them there, while with a shorter magnet a stronger current would
more speedily magnetically saturate them; this stronger current would still be
required to keep them so saturated.
If the coils of the field of force magnets and the generating coils were included in
one circuit, and all the current generated was passed through the coils of the field
magnet, a very much greater amount of current than necessary for the maintenance
of a practical magnetic maximum in the field of force magnets would be passed around
them, and the coils acting as resistances to the energy in excess of that required to
magnetize the magnet to its practical maximum would cause a great waste of
electric energy; hence I prefer to keep the coils of the field of force magnets and
the generating coils separate, and that one machine in each battery (which machine
may be termed the battery field of force generator) be used to supply the requisite
energy to the field of force magnets of the other machines in such battery (which
may be termed the supply generator).
The coils of the field of force magnets are connected as a series or in multiple are
in one circuit, while the generating coils of the supply generators of each battery
are each and all connected in a multiple are to the main conductors (though for
special purposes they may be connected as a series).
This arrangement ensures great economy, as the per cent, of the entire current
generated in each battery absorbed in keeping up the magnetic maximum in the
field of force magnets when it is furnished by one special machine of the battery, the
number given it to feed being properly calculated, being less than when a portion
of the current generated in each machine is absorbed in its own field of force
magnets.
Where a single battery of machines is used it is preferable, in view of what has
been herein before stated, for the current to the coils of the field of force magnets
of the battery generators be supplied by a small galvanic battery, but if more
than one battery of machines be used the field of force generators of all the batteries
are fed from one or more prime field of force generators connected in a multiple aro
or in a series, the field of force magnets of the prime field of force generator or
generators used being kept magnetically saturated by a weak galvanic battery 4
current, as before set forth. For instance, a weak galvanic current supplies the
field current necessary for one prime field of force generator, which in turn feeds
the field of force magnets of the field of force generators of ten batteries of twenty
or thirty machines, the ultimate effect in the generation of current depending upon
(as one important factor) the tension of the galvanic current sent through the field
of force coils of the prime field of force generators. The prime field of force gene-
rators may however be a dynamo electric machine instead of a magneto machine,
its field of force being kept up by the current generated in the machine instead of
by a galvanic current.
At the central stations all the supply generating coils or batteries thereof are 5
connected to conductors on the multiple arc system, and from these conductors
at the station main conductors (which for convenience may simply be called the
mains), connected thereto also on the multiple arc system, lead in any and all
desired directions for conveying the energy to the points where work either by
translation into light or motive power is to be done. In order to give a better 5
understanding of the method of regulating what for convenience may be called the
pressure of the current through the entire system, I will here state that all the

page_text: devices for translation of electricity are arranged on the multiple arc system, each
device being in its own derived circuit, the effect being in substance to give each a
circuit from the generating source independent of the circuit of all the other
devices. As a resultant it follows that the greater the number of translating
devices brought into circuit the less the total resistance of the circuit. For instance,
I prefer that my lamps shall each be of about one hundred ohms. resistance, then
if one lamp only be in circuit there is a resistance of one hundred ohms.; if another
lamp be put in circuit two circuits each of one hundred ohms. are provided for the
current, making the net total resistance to the current fifty ohms. Although the
resistance in each derived circuit remains unchanged, this effect is the opposite of
the effect produced by the addition of lamps when they are connected in an
ordinary straight circuit, each one then adding to the resistance of the circuit.
The bringing into operation successively of numbers of the devices, and thereby
making more paths or circuits for the current, does not appreciably lessen the
pressure or diminish the effect upon the devices in use, the active force at the
central station, viz., prime field of force generators and motive power, remaining
unchanged until the net resistance of the devices in circuit exterior to the battery
of machines is so diminished as to approach in a degree the resistance of the battery
and main conductors, it being remembered that as the machines of a battery are
connected in multiple arc the net internal resistance of a battery is as many times
less than one machine as there are machines in the battery.
To avoid any appreciable variation and ensure uniformity it is essential that any
lessening of the pressure be immediately indicated, in order that just sufficient
energy be generated and sent out to keep up an equal flow through the circuit of
each transmitting device; that is, that the pressure be kept up uniform whether
more or less translating devices be in circuit.
This is attained by providing at the central station means for constantly indicating
the pressure and for regulating the production. If appreciable variation be indicated
at such station test lights are arranged, so that an approximate visual test of the
effect of pressure upon the circuit of any translating devices in use may be shown.
From what has been said it is evident that as more or less translating devices are
brought into circuit the total resistance of the circuit, or all the circuits thereof, to
the flow of all the current generated varies.
To indicate this electro-dynamometers, galvanometers, or electrometers are placed
across the main conductor at the central station, or by return wire at any point in
the circuit, with a zero mark placed to correspond with the deflection consequent
upon the maintenance of the proper amount of pressure. It may be advisable (and
I have so done) to place at the central station a series of standard Daniel batteries,
connected by a switch circuit to the galvanometer or dynamo galvanometer, in order
that they may be frequently tested for any inaccuracy occurring from any cause
whatever. By these means any error is readily detected. To correct variations in
the pressure various means may be employed. Each supply generator may be
connected into the circuit through a switch, and each series may be likewise so con-
nected, so that the current of one or more of a series, or one or more entire series,
may be cut out or thrown into the circuit; or each machine may be arranged so as
to be disconnected from the prime motor; or, when needed, the prime motor of an
entire series may be disconnected.
The plan I prefer however is to arrange in connection with the circuit of the
battery feeding the field of force magnets of the prime field of force generator before
referred to, a series of resistances so that the energy of the battery current may
be varied, this variation causing in turn a variation in current induced in the
prime field of force generator, and in all the generators directly or indirectly
controlled thereby; where a dynamo machine is used these resistances are
to be used in the same manner in connection with the circuit including the
coils around the field magnets. For distributing the current thus generated and
regulated at the central station, I prefer to use conductors within insulated pipes
or tubing made water tight and buried beneath the earth, provision being made at

page_text: suitable intervals for house and side connections. While this plan is preferable
for many reasons it is evident that a conductor may be carried in the air or over
house tops.
While only one pair of conductors may be laid on each street, I prefer, especially
where streets are wide, to lay a pair of conductors along each side of the street near
the curb. At proper intervals street lamps may be connected thereto by derived
circuits. From the main conductors on principal streets, subsidiary main conductors
are laid through side streets. From the street conductors, wherever desired, derived
circuits are led into houses, one of the conductors passing through a suitable meter,
preferably one which measures the amount of electricity passing through. In the
house each translating device is placed in a derived circuit, the entire system of
means for generation, conduction, and translation being one great multiple arc
system. The translating device in each house may be either for light or power, or
both. For light, the electric lamp consisting of an incandescent material hermeti-
cally sealed in glass is preferred. This lamp should be of a high resistance in
comparison with the resistance of any electric lamp which to my knowledge has
hitherto been proposed. The endeavour seems to have been to lessen the resistance
of the carbon, but I have discovered that a very high resistance, say, one hundred
ohms., must be used in order that a number may be economically and successfully
used in a system.
The motor used should be so constructed that each with a constant flow or
pressure of current will give the exact power required. This requires that each
motor should be wound with finer or coarser wire, and with more or less convolutions
which determine the maximum effect of the motor.
In addition, as the motor may be run with variable loads or amounts of work to
perform, and as irregularity of speed would be a consequent thereof, it is preferable
to provide each motor with a governor which, on excessive speed, will operate to
break the circuit of the motor or to otherwise control it.
A system arranged as thus described provides for all the conditions precedent
to an economical and reliable utilization of electricity as a lighting or motive power
agent.
Within certain ascertainable limits the greater the horse power of an engine the
less the proportional cost per horse power; so in my system by consolidating at one
station the prime motive force necessary to the generation of a supply for many
consumers a great economy is attained.
As ordinarily proposed, each electric light requires its own regulation, which usually
is either thermostatic or magnetic, breaking the circuit or bringing in resistances, in
any case making a cumbrous lamp, requiring delicate management and frequent
attention. By regulating at the central station entirely I am enabled to use a
small separate lamp which may be managed with the exercise of no more than
ordinary care or attention. The distribution is so provided for that tampering
therewith is guarded against, and that connections from the mains to the translating
devices are readily made. The means for measuring ensure accuracy, and furnish
a basis for equitable charges for the amount used by any particular consumer.
In the Drawings accompanying and forming part of this Specification an arrange-
ment of means is shown for carrying my Invention into effect, although it is to be
particularly noted that the Invention is not dependent upon the specific means
and their arrangement described and shown, but that they may be varied without
departing from the spirit of my Invention. In these Drawings Fig. 1 is a plan of a
central station.
Fig. 2 is a modification of Fig. 1.
"
"
3 is a plan illustrating the street mains and house connections, with trans-
lating devices properly introduced.
4 is a plan showing a locality divided into four districts. In Fig. 1 three
batteries of generators c, c¹, c², are shown, which may be increased or diminished
as circumstances may demand. One generator c of each battery is used to generate
the current feeding the field of force magnets of the machines in its battery, the

page_text: circuit from such field generator through the field of force coils in each battery being
shown by the dotted lines 2, 2, 2.
For actuating the rotary parts an engine D is used with each battery connecting
by belt d to line of shafting E, from which belts e pass to each generator. The
coils of each magneto battery in which currents are generated are connected, as in
c and c, in multiple arc to conductors 3, 3, 3, 3, which in turn are connected in
multiple arc to main conductors 6, 6, from which lead in multiple are the street
conductors or mains 7, 7, or, as is shown in part of battery c, each machine may be
directly connected in multiple arc to the station conductor 6, 6. F is the prime
field of force generator supplying the battery field of force generators c, c, c, its
circuit being shown in dotted lines 1, 1. The field of force magnets of F are
magnetized by a current from the galvanic battery G, in whose circuit is arranged
the series of resistances H provided with the cut out K, by which more or less of
the resistances are put in or out of the circuit feeding the field magnets of F. This
arrangement forms a very effective and simple method of regulating the production
of electric current or the pressure at the central station, for the current generated
by F being dependent upon the intensity of the magnetization of its field of force
magnets which in turn depends upon the current transmitted around the magnets
by the battery G. As the resistance varies such current, it follows that by varying
the resistance in the circuit of G the current generated by F varies, which in turn
varies the current generated in c, c, c, which in turn varies the current generated in
the supply machines of the batteries, proportionate increase of current and rise of
pressure in the latter following increase of current around the magnets of F, and
vice versa.
One or more test lamps TL are placed at the central station in
derived circuits to serve as a photometric test of the pressure in the line. For more
accurately indicating variations in the pressure one or more electrometers,
galvanometers, or electro dynamometers ED are placed in derived circuits with
scale marks indicating the deflection caused by the electric pressure so as to compare
the same with the standard pressure to be maintained. By the proper use of these
indicating devices and the regulating devices described, a uniform pressure may be
readily and easily maintained through all the mains. It is preferable to connect
all circuits from the generating machines to the main conductors 6, 6, through
switches I, I, I, so that an entire battery or any portion thereof may be thrown in
or out of circuit as the demand upon the station may indicate. It is to be noted also
that the belt to the pulley of each machine is to be so arranged by any well known
plans that it may be disconnected from the motor when desired, and in this manner
the number of machines in operation may be controlled, and the effective force of
each machine while in operation is regulated by the resistance in the circuit G.
The engine may be of any desired pattern or power, the number of machines in any
one battery being limited by the power of the engine.
In Fig. 2 c, c, c, c, are the generators for the field of force magnets in batteries
not shown, and o' is the field of force generator of a battery of which three supply
generators c³, c, d, are shown connected to station conductors 6, 6, as before
explained.
The prime field of force generator F1 is in this case a dynamo-electric machine
instead of a magneto electric machine, as shown in Fig. 1, all its coils being included
in one circuit 8, 8, which passes around the field of force magnets of the battery
generators c, c, c, c, c'. The same principle of regulation is used however, the
resistance H and cut out K therefore being arranged in connection with the circuit
through F¹ so as to cause variation in the tension of the current therein, as and
with the result before explained. In this Figure there is shown what may be used
also in connection with the plan shown in Fig. 1, viz., means of testing the electro-
dynamometer ED or other indicating instrument used. From a standard Daniel's
Battery, DB a circuit tc may be formed through ED by means of the switch L
when moved to the position shown by dotted lines, so that the correctness of ED
may be ascertained periodically, and any inaccuracies which might arise be guarded

page_text: against; usually the switch L remains as shown in full lines, and ED is in a
branch between the main conductors 6, 6.
The main conductors 7, 7, Fig. 3, are to be connected with the corresponding
wires at central stations (see Fig. 1), and lead down each side of the street MS.
The conductors 7, 7, also branch off into intersecting streets IS. The small
circles o in this Figure indicate electric lamps. For street lighting they are placed
as shown in derived circuits from the street mains. From the mains derived
circuits 9, 9, lead into houses, in which are placed at suitable spots the meters M,
through which one of the house conductors passes, and by which the amount of
electricity supplied to the house is accurately determined. Upon these house
circuits are arranged lamps o, on the multiple are system, in such number, position,
and grouping, as may be desired. In these circuits I also propose to introduce
electro-motors EM, wherever desired for furnishing light motive power. From the
motor a belt i leads to a line of shafting h and pulleys a, a, for any needed dis-
tribution of the power, or the belt i may pass directly to a sewing or other
machine, a separate motor being used for each power driven machine.
Where motors are desired each preferably should be made of a power propor-
tionate to the maximum work to be done. While the electrical tension in each
machine is regulated at the central station, yet if the maximum load or work be
diminished at any particular motor its speed would necessarily be increased; it
also might be desired at times to diminish the normal speed of the motor. In
order, therefore, that some determinate speed may be maintained irrespective of
load or work, each motor should be furnished with a governor to regulate the
electric circuit and the speed.
In Fig. 4 is shown a locality divided into four supply districts; each is provided
with its own central station marked CS', CS, CS³, and CS. From each station
the mains 7, 7, lead out, as before described. At convenient points, however, say
PP, connections between the mains of the stations may be inade, as shown in
dotted lines, the effect then being to merge the entire locality into one large district
with four supply stations, the pressure through all being uniform, and each station
doing its own quota toward maintaining the uniform pressure. The use of four
stations and districts in this diagram is arbitrary, and for illustration only, as the
number actually employed in any one locality depends upon the area of the district
and the number of lights to be maintained.
What I claim as my Invention is,―
First. A system for the generation and application of electricity consisting in
the combination of means at a central station for generating the electricity and
for indicating and regulating its pressure, means for distributing the electricity,
and devices for translating it into light or motive power, substantially as set
forth.
Second. A system for the generation and application of electricity consisting in
a combination of means at a central station for generating the electricity, and for
indicating and regulating its pressure, means for distribution, means for translating,
and means for measuring the amount used by each consumer, substantially as set
forth.
Third. The method of regulating the electro motive force or pressure in the main
conductors by regulating the strength of the field of force magnets of the main
magneto electric machines, so that variation of pressure upon the connection or
disconnection of translating devices may be prevented, substantially as set forth.
Fourth. The method of regulating the amount of effect at the translating devices
by regulating the field of force current of the generators, substantially as set
forth.
Fifth. The method of regulating the generative capacity of one or a battery of
magneto electric or dynamo electric machines by regulating the current passing
through the field of force magnets, substantially as set forth.
Sixth. The method of regulating the generative capacity of one or a battery of

page_text: magneto electric or dynamo electric machines by varying the resistance of the
circuit passing around the field of force magnets, substantially as set forth.
Seventh. The method of operating a battery of magneto electric machines by
using the entire current of one machine of the battery to supply the field of force
current of the remainder, and throwing the entire current of the latter into a circuit
for use, substantially as set forth.
Eighth. The combination with one electrical circuit of a number of separate
translating devices, substantially as set forth.
Ninth. The combination with one main electrical circuit of a number of separate
translating devices arranged therein upon the multiple arc system, substantially as
set forth.
Tenth. The combination with a number of translating devices of one regulator
placed at a central station and regulating all the said devices, substantially as set
forth.
Eleventh. The combination with one or a battery of generators and a number of
translating devices of means for constantly indicating the electric pressure upon the
translating devices, substantially as set forth.
Twelfth. The combination of a number of generators and a number of trans-
lating devices, all arranged upon derived circuits or multiple arcs, substantially as
described.
Thirteenth. The combination with means for constantly indicating the electric
pressure of a battery for testing the indicating means, substantially as described.
In witness whereof, I, the said Thomas Alva Edison, have hereunto set my
hand and seal, this 29 day of June, A.D. 1880.
Witnesses,
S. L. GRIFFIN.
FRANK MCLAUGHLIN.
THOMAS ALVA EDISON. (LS.)