Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DISK ALTERNATOR
FIELD OF THE INVENTION
The present invention relates to an alternator which includes fixed coil disks
subjected to a variable magnetic flux resulting from rotating magnetic disks
and
have an alternating emf induced in them. The coils' holding disk is
manufactured
from plastic material; no metallic cores are involved to hold the coils.
Conductors
are used to remove the power from the stationary coils, requiring no
commutator
or slip ring. The disk alternator of the present invention is based on the
physical
principle of electromagnetic induction, magnetic fields, conductors of the
generating coils and movement. All three must be incorporated into a machine
that
generates current.
The advancements in alternator design improvement are becoming increasingly
important, with continuing, increasing demands for lightweight, durable,
alternator
capable to operate at low and high speed, mainly for installations like
windmills,
diesel engines, reciprocating steam engines and many other similar power
generators.
BACKGROUND OF THE INVENTION
The present invention relates to a disk alternator that produces an
alternating
current output based, at least in part, upon the use of unique arrangement and
configuration of permanent magnets and conductors- with no iron core- and
which
have a markedly different physical and mechanical configuration as compared
with
the conventional alternators.
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Many devices exist which utilize a well-known principle that electric
generators are
rotating machines that transform mechanical energy into electrical energy.
Basically, all alternators operate on the principle of electromagnetic
induction, that
is they work because a conductor is moving through a magnetic field, or a
magnetic field is moving past a conductor and inducing a motional force "emf'
in
the conductors. These alternators typically have a closely wound, rectangular
coil
which rotates about an axis which is perpendicular to a uniform magnetic field
provided by the electromagnets or by permanent magnets. The coils themselves
are wound on an iron cylinder or armature, which can be fixed or rotating. The
magnetic field is concentrated in the iron core. The speed of rotation is
directly
proportional to the frequency of the alternating current in most alternators.
The
armature, often called the stator, is the stationary member, and the magnetic
field
is rotating. The generated "emf' induced in coil is computed from the rate of
change of magnetic flux through the core or from the velocities of the
conductors
traversing the magnetic field. This applies to any coil of any shape moving
perpendicularly to a uniform magnetic field.
The changing magnetic fields will induce a magnetic field in a soft
ferromagnetic
core, magnetizing it and interacting with the coil conductors. The soft iron
core is
required only to support the coil and to canduct magnetic flux through the
coil's
conductors, and is not an operating member of current generation, unlike the
magnetic flux itself. The iron core is actually a source of losses due to the
heating,
hysteresis and braking (togging) of moving magnetic fields.
The presently built alternators, in order to be effective in power conversion,
require
a high speed of coil movement with respect to the magnetic field. However
there
are many plants having low operating speed, such as reciprocating power
plants,
steam or diesel engines, water or windmills, etc. In order to be effective,
the output
rotation of such power plants must be increased by various mechanical means,
representing an additional source of losses and maintenance requirements
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Evaluation of existing alternator designs reveals a design whereby steel
laminated
cores are used to support the coils and create a flux conduction path forward
to
the next pole. Great care is used to reduce eddy currents, heat buildup, by
stacking many insulated thin layers in these core components. They are
essential
in conventional alternators to conduct magnetic flux to the next pole, also to
mechanically hold the coils. It can be said that the conventional alternators
use
polar coordinate design methodology. This concept has evolved over the last
100
years to the point where the technology is unchanged, but the industrial
markets
show a great need for the design of an alternator capable to operate at low
and
high speed
SUMMARY OF THE INVENTION
Thus it is an object of the present invention to provide an alternator in
which the
magnetic flux of rotor's disk is maintained at its maximum and its stationary
disk
conductors have no ferromagnetic cores.
The disk alternator incorporates an innovative approach to the generation of
an
electromagnetic force. Basically the strategy switches from polar to
rectangular
coordinate generating "emf' not through angular flux conduction but linearly
through the vertical axis. The disk alternator obtains its small air gap by
stacking
multiple thin disks supporting the conductor combination. The innovation is to
eliminate the steel core and thus reduce eddy currents and all of the
associated
losses. Conventional alternators have changed very little since their
conception.
Changes have come in manufacturing techniques and improvements in material
science only.
The present invention's goal is to fulfill the need for a cost effective
alternator,
designed to be reliable through all changing operating conditions, namely,
that it
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should be able to withstand the runaway operation and work with minimal
maintenance. It has been achieved through the unique design features as
follows:
*The power disk alternator is designed to be direct driven, thus eliminating
the
need for costly gearboxes.
*Reduced maintenance through fewer operating components (no gearboxes, no
chain drives etc.).
*Safer operating conditions since there is no step-up gear ratio that can
cause the
centrifugal alternator's failure in the conventional high-speed alternators.
*Reduced-manufacturing cost based on coreless alternator design.
*Increased efficiency through an absence of iron core and its heating caused
by
eddy currents.
*Easily configurable design, which can be tailored using little redesigning or
using
existing standard components for higher or lower load conditions using a
unique
stackable design methodology.
*Flexible design for operating output frequency based on power shaft operating
rpm.
*Reduced maintenance cost based on a simple assembly, and disassembly
procedures.
It is an object of the present invention to provide an alternator wherein the
magnetic field strength is substantially uniform. It is another object of the
present
invention to provide a rotary magnetic device having substantially uniform
magnetic polarity about the arc of travel. In accordance with a preferred
embodiment of the invention, the power disk alternator comprises:
a rotor means arranged to rotate about an axis, having a circular cross
section, and comprised of at least two disks facing each other and defining at
least
one gap therebetween, said rotor means having a shaft connected to an external
source for driving the shaft in rotation about said axis;
a circular array of magnetized elements located in equally arcuately spaced
relation adjacent to the periphery of each disk, each of said magnetized
elements
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having surfaces of opposite polarity and being disposed in side-by-side
relationship in an alternating polarity configuration, magnetized elements of
one
disk facing magnetized elements of the other disk of opposite polarity to
create
between the two disks in the air gap the magnetic fields of the opposite
polarities;
5 and
a stator means comprising at least one fixed disk made of a nonmetallic
material having a conductor path on at least one surface thereof, each of said
stator means being located in one of said at least one air gap; and
connection means for connecting said conductor path to a load,
wherein when said external source drives said shaft in rotation about said
axis, said rotor means rotates and the resulting rotating magnetic field
induces a
current in said conductor path.
Further objects of the present invention will appear as the description
proceeds.
BRIEF DESCRIPTION OF THE DRAWINGS
The above mentioned and other features are objects of this invention, and the
manner of attaining them will become more apparent and invention itself will
be
better understood by reference to the following description of a preferred
embodiment of the invention taken in conjunction with accompanying drawings,
wherein:
FIG 1 is a top view of rotary magnets disks and their magnetic fluxes flow
orientation and in between them a fixed conductor disk, in accordance with one
preferred embodiment of the invention, illustrating the conductors in series
connection and their current flow induced by the movement of the magnets disk.
For the clarity of view the air gap is enlarged to more easily demonstrate the
magnetic fluxes between the magnets.
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FIG 2 is an elevational view of fixed conductors disk with its radially
oriented
conductors attached to a flat nonmagnetic material. The rotating disks have
their
magnets in relation to each other so aligned, that the north pole of one
magnet is
facing the south pole of other disk's magnet, providing a strong magnetic
field with
constant density and small air gap between the two rotating disks. The mean
diameter of these magnets is such as to assure relative large circumferential
speed in relation to radially oriented conductors. This assembly assures a
high
rate of change of magnetic flux through the conductors. The conductors are
connected in parallel, and led to outside load without the need of a slip
ring.
FIG 3 is a plane view of rotating disks with their permanent magnet elements
mounted on nonmagnetic flat disks. The magnets are arranged in side-by-side
relationship, disposed radially, outwardly from the rotor's axis, mounted flat
on the
surface of the disk. The surface of one magnet's polarity is besides an
opposite
polarity of the neighboring magnets surface.
FIG 4A is .a cross-sectional view and FIG 4B is an exploded view of multiple
magnetic disks stacked one on top of another forming small air gaps in between
them. The fixed conductor disks are located in the air gaps between the
rotating
magnetic disks forming together power disks assemblies. This stacking of a
multitude of power disks can supply more of electric power, using existing
standard elements.
DESCRIPTION OF A PREFERRED EMBODIMENT
A disk alternator according to the present invention is a rotary magnet device
composed of a rotor and stator disks designed to be direct driven, thus
eliminating
the need for costly gearboxes. The rotor means comprises rotating circular
array
disks with permanent magnets which are arranged in side by side relationship,
disposed radially, outwardly from the rotor's axis, and which are arranged on
the
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surface of the disk, with the surface of one magnet's polarity besides an
opposite
polarity of the neighboring magnet surface, thereby forming circumferentially,
variable direction of the magnetic flux emanating from the surfaces of the
magnets.
The rotating magnets disk poles form a gap between them with a generally
uniform magnetic flux density there across.
The stator disks means includes one, two or more fixed, flat nonmetallic disks
on
the surface of which a predetermined number of flat conductors with no iron
core
are disposed radially outwardly from the disk's center.
One of the stator conductor disks can be disposed fixedly in the air gap
formed by
two rotating magnets disks. The second and the third conductor disks can be in
the outside in relation to the rotating magnetic disks. The rotating magnetic
disks
move their magnetic fields in relation to the fixed power conductor (or
stator) disks,
and an alternating current is induced in the conductors.
This alternator that produces an alternating current output is based, at least
in
part, upon the use of unique arrangement and configuration of permanent
magnets and conductors with no iron core, and which have a markedly different
physical and mechanical configuration as compared with the conventional
alternators. The disk alternator was invented to fulfill the need for a
lightweight low
speed alternator, mainly for installations like windmill power generators.
Having an
ironless construction, a large amount of weight, space and heafi can be
removed.
Today's alternators must be operated at a relatively high speed to be
efficient.
However, as mentioned previously, industrial markets show a need for low speed
alternators.
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The invention disclosed herein maximizes the derivation of magnetic flux
energy
conversion into the induced electrical energy, and this fram the stored energy
stored in the interacting fields of the permanent magnets.
FIG 1 illustrates the principle of the present invention. In one embodiment of
this
invention a rotating rotor means (3) is comprised of at least two disks
defining at
least one air gap there between. The size of the air gap can be selectively
adjusted. The disks are provided with permanent magnets (1) about the
periphery
of the disks. The permanent magnets are arranged in side-by-side relationship,
in
alternating polarities, as shown in Fig. 1, and are equally spaced there
between.
Magnets of one disk face magnets of the other disk of opposed polarity, as
shown
in Fig. 1.
The rotor means rotate in direction (4) and are connected to a shaft, which is
in
turn connected to a power generating source.
The alternator of the present invention also includes at least one fixed
stator
means, comprising a disk having a circuit path on its periphery, as shown in
Fig. 2.
As the rotor disks are driven in rotation (4), they sweep their magnetic
fields (7)
across stationary conductors (2), mounted on a flat non-ferrous disk. The
movement of the magnetic flux across the conductors induces a current flow
into a
load (6). The conductors (2) are connected in series and led to outside use
without
the need of a slip ring, due to the stationary character of the conductor disk
(2).
As mentioned previously, the rotating magnets move their magnetic fields (7)
across stationary conductors mounted on the flat nonmagnetic disk. A series of
conductors exposed to a uniform magnetic field with varying direction and
rotating
with constant angular velocity develops an alternating "emf'. VIlhen a number
of
pairs of magnetic poles are spaced around the circumference of rotating disks
then each conductor on the fixed disk is swept across by the varying magnetic
field (7) and a motional "emf' is induced in it, in one direction as the
field's north
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pole passes the conductors, and in the opposite direction as the south pole is
moved across the conductors. The induced "emf' is therefore alternating, and
the
number of complete cycles per each revolution equals the number of passing
poles. The multiple structure of the magnetic poles enables a sufficiently
high
frequency to be attained without an unduly high velocity of rotation for the
rotor
disks.
In a preferred embodiment of the invention, the magnetic elements are
angularly
adjustable relative to each other to have maximum exposure of the magnetic
elements between them and thus to maximize the magnetic field characteristic
thereby controlling the degree of interaction between the magnetic fields (7).
FIG 2 illustrates a plurality of conductor elements, circularly disposed on
the
surface of non-magnetic, fixed disk. The conductor wires (2) are connected in
series, and led to the outside use of a load (6). The conductor wires have a
radial
portion, the length of which is at least equal to the size of the magnets, and
a
circumferential portion connecting two radial portions together, which
preferably lie
outside of the magnetic field. This is schematically shown in Fig. 2, where
the
dotted lines represent the magnets. In a preferred embodiment of the
invention,
the radial portions of the conductor are equally spaced.
FIG 3 shows a plurality of flat magnets (1 ) circularly disposed about, and
connected to a flat nonmagnetic disk (3). The disk (3) is rotationally
connected to
shaft (8), which, using an outside power source, is rotating the disk in the
preferred
direction. The magnets (1) are radially oriented in a side-by-side
relationship on
the surface of the disk (3), and the surface polarity of one magnet faces the
opposing polarity of the neighboring magnet's surface, as better shown in Fig.
1.
The magnets are proximate each other and their magnetic fluxes (7) are
concentrated and provide a strong magnetic field with constant density.
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Referring to FIG 4-A & B, the invention is illustrated as having three rotors
(3) on a
single common shaft (8) and two-fixed conductor disks (2). It should be
understood that more of such stator-rotor units might be used as necessary or
desirable. Such assemblies will utilize the standard rotor and stator disks
produced
5 by mass production means, and they will be stacked together to increase the
power supplied by the alternator.
Although the above description refers to the rotor disks with their circular
array of
magnetized elements (1), these elements may be arranged in any geometric
10 closed shape. The arrays of the elements (1 ) and (3) can be replaced by a
solid,
generally ring-shaped members. As shown in Figure 4B, the conductor paths on
stator (3) can also be printed on the disk, using circuit-printing technology.
The
ring shaped members can be magnetized at an angle to their respective planes
i.e. the magnetic fields can be angularly disposed relative to the respective
planes.
While this invention has been described as having a preferred embodiment, it
will
be understood that it is capable of further modifications in the shape of the
state
conductors disk and rotor's magnetic disk and their orientation with respect
to each
other. Further modifications may be made in the construction materials for
magnetic elements or otherwise to enhance operation or reliability or to
reduce the
cost. Accordingly, while the invention has been described with reference to a
specific configuration, it is to be understood that this disclosure is to be
interpreted
in it broadest sense and encompass the use of equivalent apparatus.
Therefore this application is to cover any variation, use or adaptation of the
invention following the general principle thereof and including such
departures as
come within known or customary practice in the art to which this invention
pertains
and falls within the limits of the appended claims.
