IMPROVEMENTS IN DYNAMO OR MAGNETO ELECTRIC MACHINES
Year: 1881

page_text: LETTERS PATENT to Peter Jensen, of 33, Chancery Lane, in the County of
Middlesex, for an Invention of "IMPROVEMENTS IN DYNAMO OR MAGNETO
ELECTRIC MACHINES." A communication 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 Peter Jensen at the Office of
the Commissioners of Patents on the 18th October 1881.
PETER JENSEN, of 33, Chancery Lane, in the County of Middlesex. " IMPROVE-
MENTS IN DYNAMO OR MAGNETO ELECTRIC MACHINES." (A communication from
abroad by Thomas Alva Edison, of Menlo Park, in the State of New Jersey, United
States of America.)
The object of this Invention is to produce simple and efficient means for
regulating the generative force of a dynamo or magneto electric machine, so that
only the amount of current needed in a circuit may be supplied thereto and the
pressure or electromotive force maintained constant in the circuit.
For this purpose in one case the principle is made use of that the power of an
electro magnet can be weakened by diminishing the mass of the yoke connecting
the cores, and that such power can be strengthened by increasing the mass of said
yoke until the maximum power is attained.
In applying this principle the yoke of the field of force magnet of a dynamo or
magneto electric machine is provided with a movable portion, the position of which
can be varied so as to affect the mass and conducting power of such yoke, said
movable portion acting as a magnetic circuit regulator.
This movable portion is preferably situated in the centre of the yoke, and is of
conical shape, being supported by a spindle which passes through bars connected
with the top and bottom of the yoke, and separated therefrom by plates of brass or
other nonmagnetic material.
The position of this movable cone may be adjusted by means of a hand wheel
working on the screw threaded stem of the cone, or the cone may be drawn into
the yoke by an electro magnet (preferably an axial magnet), the coils of which are

page_text: in a shunt or derived circuit from the main or consumption circuit or directly
in the main circuit. This magnet forms a means for adjusting the cone
automatically.
The result before set out is accomplished in the second case by the use of levers
or bars of iron adapted to be adjusted close to or farther away from the pole ends
and yoke of the magnet, or the pole ends alone, which partially shunt the magnetic
current or lines of force away from or around the field in which moves the
revolving armature.
These levers or bars are arranged in two ways, which are to be considered the
equivalents of each other.
First. To the outer sides of the pole ends of the magnet may be pivoted two
vertical soft iron levers rising above the ends of the yoke, and making contact with
such yoke when in line therewith. The yoke supports two brass segments which
are secured thereto and project some distance off from the same in the line of the
play of the shunting levers.
To these segments are connected the said levers by means of suitable latches or
clamps, so that such levers at their upper ends can be adjusted toward or away
from the yoke or brought into contact with the ends of the same.
Second. In place of or in addition to the first construction there may be pivoted
upon the base of the machine close to one of the pole ends of the magnet one or
two horizontal soft iron levers. The lever used is held adjustably by a brass
segment and extends across the pole ends of the magnet.
In both constructions the effect of the levers depends upon their mass and their
position with relation to the magnet. In the first construction the vertical levers
become magnetized, diminishing thereby the strength of the lines of force in the
magnetic field, and the upper end of each lever has a polarity opposite to that of
the particular pole of the magnet to which it is connected.
Consequent poles are thereby established in the yoke of the magnet opposite the
ends of the levers, which poles are increased in power by the approach of the levers
to the yoke, from which it will be seen that the lines of force are shunted away
from the field in which the induction bobbin rotates, more or less, according to the
distance of the vertical levers from the yoke.
In the second construction, supposing one lever only is used, the approach of this
lever to the pole ends of the magnet will have the effect of partially bridging or
connecting (more or less) the poles of the magnet and shunting the lines of force or
magnetic current around or away from the magnetic field. With two levers, one
on each side of the magnet, the effect would be increased.
The proper size or mass of the levers having been determined to accomplish the
effect desired, the adjustment of such levers will diminish or increase the strength
of the lines of force in the magnetic field, and in consequence thereof the current
generated in the bobbin.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Peter Jensen in the Great Seal Patent Office on the 18th April
1882.
PETER JENSEN, of 33, Chancery Lane, in the County of Middlesex. " IMPROVE
MENTS IN DYNAMO OR MAGNETO ELECTRIC MACHINES." A communication from
abroad by Thomas Alva Edison, of Menlo Park, in the State of New Jersey, United
States of America.
The object of this Invention is to produce simple and efficient means for
regulating the generative force of a dynamo or magneto electric machine, so that
only the amount of current needed in a circuit may be supplied thereto and the
pressure or electro motive force maintained constant in the circuit.
For this purpose in one case the principle is made use of that the power of an
electro magnet can be weakened by diminishing the mass of the yoke connecting
the cores, and that such power can be strengthened by increasing the mass of said
yoke until the maximum power is attained.
In applying this principle the yoke of the field of force magnet of a dynamo or
magneto electric machine is provided with a movable portion, the position of which
can be varied so as to affect the mass and conducting power of such yoke, said
movable portion acting as a magnetic circuit regulator.
This movable portion is preferably situated in the centre of the yoke, and is of
conical shape, being supported by a spindle which passes through bars connected
with the top and bottom of the yoke, and separated therefrom by plates of brass or
other non-magnetic material.
The position of this movable cone may be adjusted by means of a hand wheel
working on the screw-threaded stem of the cone, or the cone may be drawn into
the yoke by an electro magnet (preferably an axial magnet), the coils of which are
in a shunt or derived circuit from the main or consumption circuit or directly in
the main circuit. This magnet forms means for adjusting the cone automatically.
This part of the Invention is illustrated in Figures 1 and 2 of the Drawings.
Figure 1 is an end elevation of a dynamo or magneto electric machine and
connections with the yoke partly broken away to disclose the magnetic circuit
regulator, and
Figure 2, a similar view showing the magnetic circuit regulator operated auto-
matically by the electro motive force of the main or consumption circuit through
an electro magnet.
A, A¹, are the helices of the field of force magnet; B, B', the pole ends of the
same; C, the yoke or bar connecting the helix cores; D, the revolving armature of
the machine; and E, the commutator block. The commutator brushes or springs 1, 2,
lead from the block E to the main or consumption circuit 3, 4. The field of force
magnet may be energized by the derived circuit 5, 6, or by the main circuit of
another generator.
The yoke C has a central conical opening F passing vertically through it, in
which plays the conical block G forming the magnetic circuit regulator.
This cone is supported by bars a, b, secured to the yoke and separated therefrom
by brass plates.
The stem c of the conical block may be screw-threaded and receive above the
bar a a hand wheel d having an internal screw-thread, by turning which hand
wheel the position of the cone with relation to the yoke can be adjusted.
The translating devices represented by e are in derived circuits, while an electro

page_text: dynamometer H is also situated in a circuit derived from the main circuit 3, 4, and
serves to guide the attendant in his adjustment of the magnetic circuit regulator.
When the electro motive force increases beyond the desired intensity the attendant
retracts the cone, and vice versa, and thereby diminishes or increases the energy of
the field of force magnet, and consequently the electro motive force of the current
induced in the bobbin of the revolving armature.
It is possible therefore by these means to maintain a nearly constant pressure
or electro-motive force in the main circuit 3, 4.
In Figure 2 an axial magnet I is used to draw the cone into the yoke, the same
being retracted by a spring and by its own weight. The coil of this magnet is
in the main or consumption circuit.
When the magnet I is used it is not necessary to supply an electro-dynamometer,
but one may be used to check the operation of the magnet.
Were the yoke entirely cut through the uniting piece or part varying the mass
might become entirely displaced so that there would be no effect. The construction
noted then varies the mass of the yoke only within certain definite limits, the yoke
always being complete to a greater or less extent independent of the position of
the movable piece.
The result before set out is accomplished in the second case by the use of levers
or bars of iron adapted to be adjusted close to or farther away from the pole ends
and yoke of the magnet or the pole ends alone, which partially shunt the magnetic
current or lines of force away from or around the field in which moves the
revolving armature.
These levers or bars are arranged in two ways, which are to be considered the
equivalents of each other.
First. To the outer sides of the pole ends of the magnet may be pivoted two
vertical soft iron levers rising above the ends of the yoke, and making contact with
Buch yoke when in line therewith. The yoke supports two brass segments, which
are secured thereto and project some distance off from the same in the line of the
play of the shunting levers. To these segments are connected the said levers by
means of suitable latches or clamps, so that such levers at their upper ends can be
adjusted toward or away from the yoke or brought into contact with the ends of
the same.
Second. In place of or in addition to the first construction there may be pivoted
upon the base of the machine close to one of the pole ends of the magnet one or
two horizontal soft iron levers. The lever used is held adjustably by' a brass
segment and extends across the pole ends of the magnet.
In both constructions the effect of the levers depends upon their mass and their
position with relation to the magnet. In the first construction the vertical levers
become magnetized, diminishing thereby the strength of the lines of force in the
magnetic field, and the upper end of each lever has a polarity opposite to that of
the particular pole of the magnet to which it is connected.
Consequent poles are thereby established in the yoke of the magnet opposite the
ends of the levers, which poles are increased in power by the approach of the
levers to the yoke, from which it will be seen that the lines of force are shunted
away from the field in which the induction bobbin rotates, more or less, according
to the distance of the vertical levers from the yoke.
In the second construction, supposing one lever only is used, the approach of this
lever to the pole ends of the magnet will have the effect of partially bridging or
connecting (more or less) the poles of the magnet, and shunting the lines of force
or magnetic current around or away from the magnetic field. With two levers,
one on each side of the magnet, the effect would be increased.
The proper size or mass of the levers having been determined to accomplish the
effect desired, the adjustinent of such levers will diminish or increase the strength
of the lines of force in the magnetic field, and in consequence thereof the current
generated in the bobbin.
This is shown in Figures 3 and 4 of the Drawing,

page_text: Figure 3 is an elevation of a dynamo or magneto electric machine having this
improvement attached thereto, and
Figure 4, a perspective view of the magnet and base of such a machine, having
attached thereto a modified form of the improvement.
A is the base of the machine; B, B¹, the pole ends of the magnet; C, C', the
helices; D, the yoke; and E, the revolving armature, all of which are constructed
in any suitable or usual way employed in dynamo or magneto electric machines;
F, FL, are two vertical soft iron levers, which are pivoted to the outer edges of the
pole ends B, B', of the magnet and rise above the yoke D. Two brass segments G
are secured to the yoke at opposite ends thereof (only one being shown), with
which the levers are locked by any suitable means, the segments being shown as
toothed, and the levers being provided with latches for this purpose.
In the modification the horizontal soft iron lever H is pivoted to the base A
close to B, and extends across such base to the other side, being held by a segment I
and a suitable locking device. A similar lever may be situated upon the opposite
sides of the poles if desired.
The shunting effect of these levers, the diminishing thereby of the strength of
the lines of force in the magnetic field, and the consequent effect upon the current
generated inductively in the bobbin will be understood from the foregoing
description.
It is evident that electro magnets arranged in the field circuit can be used to
move the bars or levers F, F, H, automatically against the tension of springs
holding the bars normally away from the magnets, such bars forming armatures of
these regulating magnets. As the force of such magnets increases with any
increase of strength in the field circuit, it is evident they would act to draw the
bars at the pre-determined point of increase to shunt the magnetic field, and vice
versa on decrease of strength.
What is claimed is,―
First. In a dynamo or magneto electric machine a magnetic circuit regulator,
consisting of means for varying within certain definite limits the metallic mass of
the yoke connecting the limbs of the field magnet, substantially as set forth.
Second. In a dynamo or magneto electric machine the yoke of the field of force
magnet provided with a conical opening in combination with a conical block
adjustable in and out of such opening, substantially as set forth.
Third. The method of regulating the generative force of a dynamo or magneto
electric machine, consisting in varying the intensity of the magnetic field in which
revolves the induction bobbin or armature by varying within certain definite
limits the mass of the yoke connecting the limbs of the field magnet, substantially
as set forth.
Fourth. In a dynamo or magneto electric machine the combination of a magnet
or magnets having polar extensions forming a magnetic field in which the induction
bobbin rotates, an induction bobbin rotating within such field, and a magnetic bar
or lever for shunting the lines of force away from or around the magnetic field,
substantially as shown and described.
Fifth. In a dynamo or magneto electric machine the combination of a magnet
or magnets with polar extensions forming a magnetic field, an induction bobbin
rotating in such field, a magnetic bar or lever for shunting the lines of force away
from or around the magnetic field and adjustable to or from the magnet or
magnets, and means for retaining the bar at any desired adjustment, substantially
as shown and described.
Sixth. In a dynamo or magneto electric machine the combination with a magnet
of a bar or lever adapted to magnetically connect the polar and yoke ends of the
magnet, being pivoted to or upon one end and adjustable to or from the other end,
substantially as shown and described.
Seventh. The method of controlling or regulating the induction of current in a
bobbin rotating upon its axis within a magnetic field, which consists in shunting

page_text: away from or around said field more or less of the lines of magnetic force, which
normally would pass through and strengthen such field, substantially as and for
the purpose set forth.
In witness whereof, I, the said Peter Jensen, have hereunto set my hand and
seal, this Seventeenth day of April, in the year of our Lord One thousand
eight hundred and eighty two.
P. JENSEN. (L.S.)