IN APPARATUS FOR DEVELOPING ELECTRIC CURRENTS AND REGULATING THE ACTION OF THE SAME IN CIRCUITS THAT PASS TO ELECTRIC LIGHTS OR ELECTRO MAGNETIC ENGINES."
Year: 1880

page_text: LETTERS PATENT to Thomas Alva Edison, of Menlo Park, in the State of
"IMPROVEMENTS
New Jersey, United States of America, for an Invention of
IN APPARATUS FOR DEVELOPING ELECTRIC CURRENTS AND REGULATING THE
ACTION OF THE SAME IN CIRCUITS THAT PASS TO ELECTRIC LIGHTS OR
ELECTRO MAGNETIC ENGINES."
PROVISIONAL SPECIFICATION left by the said Thomas Alva Edison at the
Office of the Cominissioners of Patents on the 3rd January 1880.
THOMAS ALVA EDISON, of Menlo Park, in the State of New Jersey, United States
of America. " IMPROVEMENTS IN APPARATUS FOR DEVELOPING ELECTRIC CURRENTS
AND REGULATING THE ACTION OF THE SAME IN CIRCUITS THAT PASS TO ELECTRIC
LIGHTS OR ELECTRO MAGNETIC ENGINES."
In my system of electric lighting I have proposed in a previous Patent to
regulate the pressure or electro-motive force at the central station by varying the
strength of the field magnets around the induction bobbins connected to the main
conductors.
Any rise or fall in the electro motive force due to putting on or off lamps is to be
indicated by an electro meter. I find that an electro dynometer similar to that of
Webber, but of high resistance, is an improvement upon the electro meter, owing
to its greater reliability. Two of such are used, and connected across the main
conductors in multiple arc.
In my system a city is to be divided up into districts; in each district there is a
central station, which station is provided with sufficient motive power and electric
generators to supply half a mile radius.
At this station I employ, say, five engines, each of 250 horse power; each engine
runs by a belt a separate line of shafting. On this shafting is belted; say, 40
electric generators, so that each engine and its system of generators may be con-
sidered complete within itself. 2 large rods of copper are conveyed in proximity
to all the generators, and connecting levers are arranged so that any generator may
be placed across and feed into the two main conductors.
All the generators when connected to the mains are connected in multiple arc,
and the field magnet of every generator is so wound, or the pulleys upon its shaft
so made that by increase or decrease of speed, or by a weakening or strengthening

page_text: of the field magnet the electro motive force of the induction may be adjusted to
exactly the same electro motive force in all the machines.
I employ several subsiduary electro generators belted on the shaft of the first
engine, which are all in use, and the currents from these machines are conveyed by
leading wires to the field magnet of all the generators, and serve to keep a constant
field. A second series of these subsiduary machines is connected to the shaft of the
second engine, and connected in duplicate so as to be used in case of emergency or
in case the first engine stops. A switch is provided for changing one subsiduary
generator from one set to another set, so that the change can be made gradually.
The subsiduary generatora are also arranged in multiple arc, but the field magnets
of main line generators are so connected that there will be a row of, say, 10 magnets
connected in series, and these sets connected in multiple arc.
Switches are provided
whereby, say, 10 field magnets are disconnected at once,
having previously been disconnected from the mains.
the induction bobbin
For energizing the field' magnets of the subsiduary generators I use a dynamo
electric machine, the current from which passes through the field magnets of all the
subsiduary generators either in series or in multiple arc.
In this circuit I place a large number of resistance coils of large wire, and sub-
divided so that each has, say, of an ohm. resistance. A wire between each
resistance coil leads to a rotary commutator, which by being turned short circuits
a greater or less number of resistance coils, thus increasing or decreasing the
strength of the currents in the field magnets of the subsiduary generators; this in
its turn increases or decreases the strength of the current in the indication bobbins
between them, and this current in its turn increases or decreases the strength of
the field magnets of the main line generators, and cause a rise or fall in the pressure
or electro-motive force of the line currents, according as more or less energy is
drawn from the stations by putting on or taking off lamps or electric engines.
Thus I am enabled to cause a rise or fall in the pressure or electro-motive force
by turning of the commutator handle. To indicate the rise and fall of electro-
motive force the operator at the commutator has before him the electro dynometer,
as well as several standard lamps, to indicate the rise and fall.
This apparatus I propose to place in a separate room from the main rooms con-
taining the generators and engines, the connection therewith being made by wires,
but the movements of the commutator are transferred by gearing and shafts to
large dials, one in the generator room and one in the engine room, so that the
station master may know the proper time to start up or stop down one or more of
the engines. It may sometimes happen in practice that from the breaking of belts
or a wire or other causes that a generator will cease to supply electricity to the main
lines, even when the induction bobbin is intact; this will cause the currents from
the other generators to pass through this generator, and perhaps burn the wire.
To prevent this I interpolate a short wire in the induction bobbin circuit, made of
bismuth or other fusible metal, which will melt and break the circuit, and save the
wires of the generator before too great a heat is reached.
Between each generator I place a loose pulley supported by a gudgeon, to which
pulley the belt may be shifted in case a generator is to be repaired when the system
of generators of which it is one is in use.
It is well known that at different parts of the main circuit outside of the
generators electric engines almost similar to the generators may be placed for the
purpose of giving out power to the shafting.
I find that several electro-magnetic engines giving varying amounts of power,
from 20 horse to 1 of a horse, may be worked in multiple arc.
The less the power
required the smaller the engine, and the greater the power required the finer the
wire used, and I find that it is preferable to place the greatest length of the wire
and resistance upon the field magnet.
In using these electro magnetic engines in multiple arc for running a sewing
machine or other small machine I arrange a switch for disconnecting the machine
from the circuit, a belt to connect the motor with the sewing machine, using a

page_text: very small pulley on the motor and a large pulley on the sewing machine so as to
allow of high speeds in the motor. I regulate the speed of sewing by a friction
lever pressing on the driving pulley of the sewing machine, which lever being con-
nected to the foot rest may be pressed lightly or heavily on the pulley of the
sewing machine, and thus increase or diminish its speed instantly or stop it
altogether. The pulley of the motor being a friction pulley allows the motor shaft
to revolve at a slower speed even when the belt is stopped."
When the motor is arranged to pump water to a tank I use a float which, when
the water becomes too low, closes a circuit and connects the motor to the main line,
and when the water is sufficiently high the float serves to disconnect the motor
from the electric circuit.
For running machine shops with these motors, and where an even speed is
required, I arrange upon the shaft of the motor a governor working in the ordinary
nanner, but which when the speed has reached a certain point causes a lever to
open the circuit and disconnect the motor from the circuit.
These motors can be worked upon the same main conductors as the lamps.

page_text: 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 1st
July 1880.
1
THOMAS ALVA EDISON, of Menlo Park, in the State of New Jersey, United States
of America. "IMPROVEMENTS IN APPARATUS FOR DEVELOPING ELECTRIC CURRENTS
AND REGULATING THE ACTION OF THE SAME IN CIRCUITS THAT PASS TO ELECTRIC
LIGHTS OR ELECTRO MAGNETIC ENGINES."
In my system of electric lighting I have proposed in a previous Patent to
regulate the pressure or electromotive force at the central station by varying the
strength of the field magnets around the induction bobbins connected to the main
conductors, any rise or fall in the electro motive force due to putting on or off
lamps being indicated by an electrometer. I find that an electro dynamometer
similar to that of Webber, but of high resistance, is an improvement upon the
electrometer owing to its greater reliability. Two of such are used and connected
across the main conductors in multiple arc. In my system a city is to be divided
up into districts; in each district there is a central station, which station is provided
with sufficient motive power and electric generators to supply half a mile radius.
At this station I employ, say, five engines, each of two hundred and fifty horse
power. Each engine runs by a belt a separate line of shafting; on this shafting
is belted, say, forty electric generators, so that each engine and its system of
generators may be considered complete within itself. Two large rods of copper are
in proximity to all the generators, and connecting levers are arranged so that any
generator may be placed across and feed into the two main conductors. All the
generators when connected to the mains are connected in multiple arc, and the
field magnet of every generator is so wound, or the pulleys upon its shaft so made,
that by increase or decrease of speed, or by a weakening or strengthening of the
field magnet, the electro motive force of the induction may be adjusted to exactly
the same electromotive force in all the machines. I employ several subsidiary
electric generators belted on the shaft of the first engine which are all in use, and
the currents from these machines are conveyed by leading wires to the field magnet
of all the generators and serve to keep a constant field. A second series of these
subsidiary machines is connected to the shaft of the second engine, and connected
in duplicate so as to be used in case of emergency or in case the first engine stops.
A switch is provided for changing one subsidiary generator from one set to
another set, so that the change can be made gradually. The subsidiary generators
are also arranged in multiple arc, but the field magnets of main line generators are
so connected that there will be a row of, say, 10 magnets connected in series, and
these sets connected in multiple arc. Switches are provided whereby, say, ten
field magnets are disconnected at once, the induction bobbin having previously
been disconnected from the mains. For energizing the field magnets of the sub-
sidiary generators I use a dynamo electric machine, the current from which passes
through the field magnets of all the subsidiary generators either in series or in
multiple arc. In this circuit I place a large number of resistance coils of large
wire and subdivided, so that each has, say, one fiftieth of an ohm. resistance.
A wire between each resistance coil leads to a rotary commutator, which by
being turned short circuits a greater or less number of resistance coils, thus
increasing or decreasing the strength of the current in the field magnets of the
subsidiary generators, this in its turn increases or decreases the strength of the
current in the induction bobbins between them, and this current in its turn
increases or decreases the strength of the field magnets of the main line generators,
and causes a rise or fall in the pressure or electromotive force of the line currents,
according as more or less energy is drawn from the stations by putting on or
taking off lamps or electric engines. Thus I am enabled to cause a rise or fall in
the pressure or electromotive force by turning of the commutator handle. To
indicate the rise and fall of electromotive force the operator at the commutator has
before him the electro dynamometer, as well as several standard lamps, to indicate

page_text: the rise and fall. This apparatus I propose to place in a separate room from the
main rooms containing the generators and engines, the connection therewith being
made by wires, but the movements of the commutator are transferred by gearing
and shafts to large dials, one in the generator room and one in the engine room, so
that the station master may know the proper time to start up or stop down one
or more of the engines. It may sometimes happen in practice that from the
breaking of belts, or a wire, or other causes, that a generator will cease to supply
electricity to the main lines, even when the induction bobbin is intact; this will
cause the currents from the other generators to pass through this generator and
perhaps burn the wire. To prevent this I interpolate a short wire in the induction
bobbin circuit made of bismuth or other fusible metal, which will melt and break
the circuit, and save the wires of the generator before too great a heat is reached.
Between each generator I place a loose pulley supported by a gudgeon, to which
pulley the belt may be shifted in case a generator is to be repaired when the
system of generators of which it is one is in use. It is well known that at different
parts of the main circuit outside of the generators, electric engines almost similar
to the generators may be placed for the purpose of giving out power to shafting.
I find that several electro magnetic engines giving varying amounts of power, from
twenty horse to 1 of a horse, may be worked in multiple arc. The less the
power required the smaller the engine, and the greater the power the finer the
wire used, and I find that it is preferable to place the greatest length of the wire
and resistance upon the field magnet.
In using these electro magnetic engines in multiple arc for running a sewing
machine or other small machine, I arrange a switch for disconnecting the machine
from the circuit, a belt to connect the motor with the sewing machine, using a very
small pulley on the motor and a large pulley on the sewing machine, so as to
allow of high speeds in the motor. I regulate the speed of sewing by a friction
lover pressing on the driving pulley of the sewing machine, which lever being
connected to the foot rest may be pressed lightly or heavily on the pulley of the
sewing machine, and thus increase or diminish its speed instantly or stop it
altogether; the pulley of the motor being a friction pulley allows the motor shaft
to revolve at a slower speed even when the belt is stopped.
When this motor is arranged to pump water to a tank I use a float, which, when
the water becomes too low, closes a circuit and connects the motor to the main
line, and when the water is sufficiently high the float serves to disconnect the
motor from the electric circuit. For running machine shops with these motors, and
where an even speed is required, I arrange upon the shaft of the motor a governor
working in the ordinary manner, but which when the speed has reached a certain
point, causes a lever to open the circuit and disconnect the motor from the circuit.
These motors can be worked upon the same main conductors as the lamps.
Having now described the nature of my said Invention and in what manner the
same is or may be performed, I declare that I claim as my Invention,―
The method herein specified of regulating and controling the action of magneto
electric generators and governing the electro motive force throughout a system of
conductors, in which system are included electric lamps or magneto electric motors,
substantially as set forth.
In witness whereof, I, the said Thomas Alva Edison, have hereunto set my
THOMAS ALVA EDISON. (L.S.)
Witnesses,
CHAS. H. SMITH, 140, Nassau St., New York.
GEO. T. PINCKNEY,
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