IMPROVEMENTS RELATING TO DYNAMO OR MAGNETO-ELECTRIC MACHINES FOR REGULATING THE GENERATIVE CAPACITY OF SUCH MACHINES
Year: 1882

page_text: LETTERS PATENT to Thomas John Handford, of No 42, Southampton
Buildings, in the County of Middlesex, Patent Agent, for an invention of
"IMPROVEMENTS RELATING TO DYNAMO OR MAGNETO-ELECTRIC MACHINES FOR
REGULATING THE GENERATIVE CAPACITY OF SUCH MACHINES."-A communi-
cation from abroad by Thomas Alva Edison of Menlo Park, in the State of
New Jersey United States of America.
PROVISIONAL SPECIFICATION left by the said Thomas John Handford
at the Office of the Commissioners of Patents on the 11th March 1882.
THOMAS JOHN HANDFORD of No 42 Southampton Buildings in the County of
Middlesex Patent Agent "IMPROVEMENTS RELATING TO DYNAMO OR MAGNETO
ELECTRIC MACHINES FOR REGULATING THE GENERATIVE CAPACITY OF SUCH
MACHINES a communication from abroad by Thomas Alva Edison of Menlo Park
in the State of New Jersey United States of America.
"
This Invention has for its object the provision of simple and efficient means and
methods for automatically regulating the generative capacity of dynamo or magneto
electric machines, which means will act automatically upon the addition and
removal of lamps or other translating devices to produce corresponding changes in
the energy of the exciting or field of force magnet.
According to one modification, the lamps or other translating devices are divided
into groups, the lamps of each group being those that are in multiple arc or derived
circuits from the same pair of conductors branching from the main conductors.
There is provided in connection with each group means for regulating the current
energizing the field magnet of the machine operated by the current generated and
acting automatically upon the addition or removal of translating devices in the
group. This means may be an electro-magnet in one of the branch conductors
having an armature lever retracted by a spring and making and breaking a circuit,
which may be a shunt around a definite resistance in the field circuit or an

page_text: additional field circuit, the result in either case being an increase in energy of the
field magnet by the closure of the circuit controlled by each of these electro-
magnets.
Each of these magnets is so constructed and arranged with relation to its
armature lever, that it will not draw the lever to its front contact until a number
of the lamps of the group have been turned on, so that the additional energy given
to the field magnet by the operation of the devices connected with each group will
be sufficient for the supply of all the lamps of the group.
According to another modification there is provided a series of devices, operated
by the current generated, arranged to act successively as more translating devices
are placed in circuit, to increase the current energizing the field magnet of the
generator, and also acting successively as translating devices are taken out of
circuit to decrease the current energizing the field magnet
These devices act to open and close circuits, throwing in or out resistance or
opening and closing additional field of force circuits.
A series of electro-magnets is preferably used for this purpose. The magnets are
made to act successively by providing their armatures with retractors of graduated
power, or by placing the armatures at different distances from the magnets, or by
winding them differently; or the relation between the magnets and their armatures
may be graduated in any other suitable manner.
These electro-magnets can be arranged in series in a shunt around a resistance
placed in one of the main conductors; or in multiple arc across such a shunt
circuit; or in multiple are in one of the main conductors; or in series in a multiple
arc circuit connecting the two main conductors. When the electro-magnets are in
one of the main conductors or in a shunt therefrom, their armatures are arranged
to close at their front contacts the circuits for increasing the flow of current
through the coils of the field magnet; but when such magnets are in a multiple are
or derived circuit from the main conductors they close circuits at their back
contacts.
The reason for this is evident. The addition of lamps in multiple are circuits
causes a greater flow of currents through the main conductors but draws it away
from other multiple arc circuits. Hence it is when magnets in the main conductors
would be strengthened and those in multiple arc circuits therefrom weakened, by
the addition of lamps, that the energy of the field magnet should be increased.
The field circuit may be a single multiple arc circuit having a number of
resistances, around which are shunt circuits to the armature levers and to one of
the contacts of each lever, so that the resistances will be thrown in and out in
succession. Or the electro-magnets arranged in any of the ways hereinbefore
referred to may be used to open and close circuits of a divided field.
Sometimes the current in the main conductors is increased by an increase of the
speed of the speed of the steam engine driving the generator, causing the lights to
flicker. This would be compensated for by the series of electro-magnets in multiple
are from the main conductors since they would be affected the same as the lamps and
would decrease the energy of the field magnet when the speed of the engine is
increased; but the electro-magnets in one of the main conductors or in a shunt
therefrom would have a tendency to still further increase the energy of the field
magnet. In order to obviate this it is necessary to use with the latter means of
regulation, some device, or a series of devices which will act to weaken the energy
of the field magnet when there is an increase of current due to a sudden increase
in the speed of the engine. This is done, preferably by means of a device or series
of devices which acts to weaken the series of magnets controlling the circuits for
directly regulating the current energizing the field magnet, causing such controlling
magnets to open more or less of their circuits and maintain the electro-motive
force practically.
Electro magnets are preferably used for this purpose. One or a number may be
used. If a number is used, they will be graduated to work successively. These
latter electro-magnets (one or more) are placed in multiple arc across the main

page_text: conductors and close at their front contacts circuits around a resistance or around
the circuit or circuits of the first magnets. The effect of closing the circuit or
circuits controlled by the last described electro-magnet or magnets, is to draw
current away from the first magnets and weaken them, causing a correspondent
weakening of the field.
With all forms of regulating devices hereinbefore explained the translating
devices are in multiple arc circuits; the field circuit is also a multiple are circuit;
and the armature of the machine is in another multiple arc circuit; (all these
multiple are circuits being from the same main conductors).
By arranging all these elements in multiple arc circuits the use of a separate
exciting machine in small or isolated plants is avoided.
These regulating devices are however applicable also to batteries of machines.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas John Handford in the Great Seal Patent Office on the
11th September 1882.
"
THOMAS JOHN HANDFORD of No 42 Southampton Buildings in the County of
Middlesex patent Agent
IMPROVEMENTS RELATING TO DYNAMO OR MAGNETO
ELECTRIC MACHINES FOR REGULATING
GENERATIVE CAPACITY OF SUCH
MACHINES a communication from abroad by Thomas Alva Edison of Menlo Park
in the State of New Jersey United States of America.
"
THE
The said Invention has for its object the provision of simple and efficient means
and methods for automatically regulating the generative capacity of dynamo or
magneto electric machines, which means shall act automatically upon the addition
and removal of lamps or other translating devices to produce corrisponding changes
in the energy of the exciting or field of force magnet
According to one part of the said Invention the lamps or other translating
devices are divided into groups, the lamps of each group being those that are in
multiple arc or derived circuits from the same pair of conductors branching from
the main conductors.
There is provided in connection with each group means for regulating the
current energizing the field magnet of the machine, operated by the current
generated, and acting automatically upon the addition or removal of translating
devices in the group. This means may be an electro magnet in one of the branch
conductors having an armature lever retracted by a spring and making and
breaking a circuit, which may be a shunt around a definite resistance in the field
circuit or an additional field circuit, the result in either case being an increase in
energy of the field magnet by the closure of the circuit controlled by each of these
electro-magnets.
Each of these magnets is so constructed and arranged. with relation to its armature
lever, that it will not draw the lever to its front contact until a number of the
lamps of the group have been turned on, so that the additional energy given to the
field magnet by the operation of the devices connected with each group will be
sufficient for the supply of all the lamps of the group.
In the Specification to former Letters Patent granted to Edward Griffith Brewer
for an invention communicated to him by the said Thomas Alva Edison dated
June 7th 1881 No 2482 there is described an arrangement for automatically
regulating the energy of the field magnet simultaneously with controlling a lamp
or group of lamps, but the present invention embodies an improvement thereon,
in that the devices are worked automatically by the current generated upon
the manipulation of the usual circuit controllers or switches of the lamps of a
group.
According to another part of the present invention there is a provided a series of
devices, operated by the current generated arranged to act successively as more
translating devices are placed in circuit to increase the current energizing the field
magnet of the generator and also acting successively as translating devices are
taken out of circuit to decrease the current energizing the field magnet.
These devices act to open and close circuits, throwing in or out resistance or
opening and closing additional field of force circuits.
A series of electro magnets is preferably used for this purpose.
The magnets are made to act successively by providing their armatures with
retractors of graduated power or by placing the armatures at different distances
from the magnets or by winding the latter differently or the relation between the
magnets and their armatures may be graduated in any other suitable manner.

page_text: These electro-magnets can be arranged in series in a shunt around a resistance
placed in one of the main conductors; or in multiple are across such shunt circuit;
or in multiple are in one of the main conductors; or in series in a multiple, arc
circuit connecting the two main conductors. When the electro magnets are in one
of the main conductors or in a shunt therefrom, their armatures are arranged to
close at their front contacts the circuits for increasing the flow of current
through the coils of the field magnet; but when such magnets are in a multiple
arc or derived circuit from the main conductors they close circuits at their back
contacts.
The reason for this is evident. The addition of lamps in multiple arc circuits
causes a greater flow of current through the main conductors but draws it away
from other multiple arc circuits. Hence it is when magnets in the main conductors
would be strengthened and those in multiple arc circuts therefrom weakened by
the addition of lamps that the energy of the field magnet should be increased.
Sometimes however the current in the main conductors is increased by an
increase of the speed of the steam engine driving the generator, causing the lights
to flicker. This would be compensated for by the series of electro magnets in
multiple are from the main conductors, since they would be affected the same as
the lamps and would decrease the energy of the field magnet when the speed of
the engine is increased; but the electro-magnets in one of the main conductors or
in a shunt therefrom would have a tendency to still further increase the energy
of the field magnet. In order to obviate this it is necessary to use with the latter
means of regulation, some device or series of devices which will act to weaken the
energy of the field magnet when there is an increase of current due to a sudden
increase in the speed of the engine. This is done preferably by means of a device
or series of devices which acts to weaken the series of magnets controlling the
circuits for directly regulating the current energizing the field magnet causing such
controlling magnets to open more or less of their circuits and maintain the electro-
motive force practically constant.
Electro magnets are preferably used for this purpose. One or a number may be
used. If a number is used they will be graduated to work successively. These
latter electro magnets (one or more) are placed in multiple arc across the main
conductors and close at their front contacts circuits around a resistance or around
the circuit or circuits of the first magnets. The effect of closing the circuit
or circuits controlled by the last described electro-magnet or magnets is to draw
current away from the first mentioned magnets and weaken them, causing a
corrisponding weakening of the field,
With all forms of regulating devices hereinbefore explained the translating
devices are in multiple arc circuits; the field circuit is also a multiple arc circuit;
and the armature of the machine is in another multiple arc circuit; (all these
multiple are circuits being from the same main conductors).
By arranging all these elements in multiple arc circuits the use of a separate
exciting machine in small or isolated plants is avoided.
These regulating devices are however applicable also to batteries of machines.
And in order that the said invention may be perfectly understood, I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several Figures on the accompanying sheet of drawings.
Figures 1 and 2 of the accompanying drawings are diagrammatic views shewing
regulating devices in connection with groups of lamps according to the first part of
the said Invention.
Figs. 3 to 7 inclusive are diagrammatic views shewing the graduated or
successively acting devices for regulating the generator according to the second
part of the said Invention.
Referring to figures 1 and 2 which represent regulating devices in connection
with groups of lamps. A is the generator and 1, 2 the main conductors from the
same. The lamps or other translating devices a are in multiple arc circuits from

page_text: pairs of branching conductors 5, 6; 7, 8; 9, 10; any number of which branching
conductors may be used.
In one of the conductors of each pair of branching conductors is placed an electro
magnet B provided with an armature f.
In fig 1 the field circuit is a multiple arc circuit 3, 4 provided with a number
of resistances R, R1, R2, there being one set of resistances for each pair of branching
conductors. There are shunt circuits b, e, d around these resistances to the
armature levers f, and their front contacts i by the opening or closure of each of
which circuits by its respective electro magnet B, the energy of the field magnet is
diminished or increased.
In lieu of cutting out and throwing in resistance, the electro magnets may be
used to close and open additional field circuits. This modification is illustrated in
figure 2. The field circuit is a divided circuit, three circuits 3 g, 3 h, 3k being
shewn in the example illustrated. Circuit 3 g is constantly closed. Circuits 3 h 3 k
are opened and closed by the movement of the armature levers f from and to their
front contacts thus varying the energy of the field magnets as before.
The apparatus operates in the following manner viz :—
When there are few lamps in circuit not sufficient to enable the electro-magnets B
to attract their armature levers f the minimum current will flow through the field
circuit. In the construction shewn in figure 1, the current will flow through all
the resistances R, R1, R2, while in the construction shewn in figure 2 it will flow
only through the constantly cloed division 3 g. of the field circuit. After a definite
number of lamps has been added to any particular group (for example the group in
circuit 7, 8,) the magnet B of that group will have sufficient strength to draw the
lever against its front contact i This will cut the resistance R₁ out of the field
circuit in the modification figure 1 and close the additional field circuit 3k in
figure 2 as shewn in the drawings. The field magnet will be strengthened and the
electromotive force of the machine increased to the desired extent for supplying all
the lamps of the group in 7, 8,
As the lamp circuits are broken the magnet B will weaken until ƒ separates
from its front contact i, when the resistance R¹ will be thrown into the field circuit
in the modification figure 1 and the circuit 3k (Figure 2) will be opened, the
electromotive force being thereby decreased. This operation occurs in connection
with each group of lamps.
The second part of the said invention which relates to the use of graduated or
successively acting devices for regulating the generator is illustrated in Figs. 3 to 7
inclusive of the accompanying drawings.
In these figures D is the generator, 1. 2, the main conductors therefrom, and e
the translating devices placed in multiple are or derived circuits.
A, B, C, are electro magnets having armature levers c, c', c²; These are retracted
by springs d, d', d², (Figures 3, 4, 6 and 7) or by weights f, f¹, ƒ³, (Fig. 5.) which
are made of graduated power so that the armature lovers will be moved in suc-
cession. These electro magnets may be placed in series in a shunt 3, 4, around
resistance R in one of the main conductors (fig 3) or in multiple arc in such
shunt (fig 5); or in multiple are directly in one of the main conductors (fig 4);
or in one or more multiple arc circuits 7, 8 from the main conductors 1, 2 (figs. 6
and 7).
The field circuit may be a single multiple arc circuit 5, 6, having a number of
resistances E, E¹, E², around which are shunt circuits b, a, to the armature levers
ccc and to one of the contacts x, of each lever, so that the resistances will be
thrown in and out in succession (figs 3, 4 and 6). Or the electro magnets
arranged in any of the ways shewn, may be used to open and close circuits of a
divided field (Figs. 5 and 7) four circuits 9, 10; 9 g; 9, h; 9. i; being shewn in
those figures.
The apparatus operates in the following manner :-viz
With a small number of lamps in circuit the minimum current will flow in the
´field circuit through all the resistances E F1 F2 in the construction shown in

page_text: figures 3, 4, and 6 and through the constantly closed field circuit 9, 10 in the
construction shewn in figs, 5, and 7.
With the arrangement shewn in figures 3, 4, and 5 an increase in the number
of lamps in circuit will cause a greater flow of current in the main conductors 1. 2.
Hence more current will flow through the coils of magnets A, B, C, in the shunt
circuit 3, 4, and in one of the main conductors and these magnots will attract their
armatures in succession, which by forming contacts at x, will cut resistance out of
the field circuit (Figs 3 & 4) or close new field circuits (Fig. 5) the electromotive
force of the machine being thus increased as required. For example if the
generator is designed to supply sixty lamps, the magnet A, would act when twenty
lamps are put on, the magnet B when forty lamps are in circuit, and the magnet C
when the full number of lamps is in circuit. The reverse operation takes place
when lamps are taken out of circuit.
In the examples illustrated in the drawings the magnet A is represented as
having acted, its armature resting against its contact at x and cutting out
resistance E, (figs. 3 and 4) or closing an additional field circuit 9, g (Fig. 5).
If however the electro motive force should be increased by an increase in the
speed of the engine and without increasing the number of lamps the magnets
A. B. C if no other devices were used, would act and still further increase the
electromotive force and the lamps would be raised to higher than normal incan-
descence. This is prevented by the employment of the magnet M, (Figs. 3, 4 and 5)
which is placed in a multiple are circuit m. m, from the main conductors and opens
and closes a shunt circuit N, N, around the resistance R (Figs. 3 and 5.) or around
the electromagnets A. B. C (Fig. 4). This circuit may have a resistance R¹
(Fig. 4) or r, (Figs. 3 and 5).
When the electromotive force is increased by an increase in the speed of the
engine the magnet M, closes the shunt around the resistance R (Figs 3 and 5) or
the magnets A. B. C (Fig. 4) and weakens the magnets A. B. C causing them to
throw resistance into the field circuit, or open divisions of the field circuit thus
maintaining the lamps at normal incandescence. Several of the electro magnets M
may be employed placed in separate circuits and operating successively. With the
arrangement shewn in figures 6 and 7, the magnets A. B. C are affected exactly
the same as are the lamps and regulate for variations in electromotive force
caused either by changes in the number of lamps or in the speed of the engine.
If the electromotive force is decreased by adding lamps or by a reduction in the
speed of the engine the magnets A B and C will successively be weakened and
their armature levers c, c', c³, will be drawn by their springs d, d', d³, against their
back contacts and cut resistance out of the field circuit (Fig 6) or close additional
field circuits (Fig 7). If the electromotive force is increased by taking off lamps
or by an increase in the speed of the engine, the magnets A, B, C, will act in
succession to throw resistance into the field circuit (Fig. 6) or open divisions of the
field circuit (Fig. 7).
In the examples illustrated in Figs. 6 and 7 the magnet A is assumed to have
acted breaking the shunt circuit b, a, and throwing resistance E into the field
circuit (Fig. 6) or breaking the division 9, g. of the field circuit (Fig. 7).
It will thus be seen from the foregoing description that the normal candle power
of the lamps will be maintained practically constant.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is :-
1st The combination with the generator, and the groups of translating devices
arranged in multiple are, of means in connection with each group operated by the
current generated for regulating the current energizing the field magnet of the
generator, acting automatically upon the addition or removal of translating devices
in the group, substantially as hereinbefore described.

page_text: 2nd The combination with the generator and translating devices in multiple
arc, of a series of devices operated by the current generated and arranged to act
successively as more translating devices are placed in circuit to increase the
current energizing the field magnet of the generator substantially as hereinbefore
described.
3rd The combination with the features set forth in the preceding claiming
clause, of a device or series of devices for compensating for an increase in the
speed of the engine substantially as hereinbefore described.
In witness whereof I the said Thomas John Handford have to this my
Specification set my hand and seal this eighth day of September in the
year of our Lord One thousand eight hundred and eighty two.