Abstract:
The permanent magnet electric generator includes a plurality of ferromagnetic bars disposed in spaced apart relation about the circumference of a non-magnetic, annular rotor body circumferentially surrounded by an even plurality of stator rows uniformly distributed around and arranged normal to the rotor. Each row of stators has a plurality of interconnected stators, each stator having a nonconductive innermost core surrounded by ferromagnetic material and successive layers of insulation, windings of conductive wire, and layers of ferromagnetic material circumferentially surrounding the underlying layers in a pre-determined repeating pattern.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to electric power generators. More specifically, the present invention relates to permanent magnet electric generators. 
   2. Description of the Related Art 
   The basic construction of electric power generators has not changed significantly over the years, taking the form of a rotating a magnetic within a ring of wound wire. Improvements in construction for increasing the efficiency of the generator have been the object of much research and innovation. 
   U.S. Pat. No. 1,726,042, issued to Reis in 1929, discloses a generator having a rotor having permanent magnets. These magnets are at least partially encircled with ferromagnetic metal to control eddy currents and to increase permeability of local portions of the magnetic field. 
   U.S. Pat. No. 5,447,758, issued to Shimizu in 1985, discloses a cylindrical permanent magnet having at least eight poles. 
   U.S. Pat. No. 4,780,634, issued to Masterman in 1988, discloses an electric generator having a rotor, a plurality of pole sections spaced around the circumference of a rotor core at a constant pole section pitch, a toothed stator (a stationary part in a machine in or about which a rotor revolves), two or more independent windings, and a plurality of bridge members to separate adjacent windings. 
   Japanese Patent Document No. 3-82348, published in 1991, discloses a rotor for a generator wherein the magnetic field is augmented by a second series of magnets placed inside an external ring of primary magnets. 
   U.S. Pat. No. 5,457,870, issued to Canders in 1995, discloses an improved rotor for electric machines having a high rotational speed. The rotor described in the &#39;870 patent has a rotor core and a rotor shell comprising a binding made of fiber-reinforced plastics radially supporting the rotor core. 
   Advances in rotor and stator design have been disclosed in several devices. U.S. Pat. No. 6,487,770, issued to Bernauer et al. in 2002, discloses rotors or stators cut out from rolled sheet metal with a predominant magnetic direction and which are stacked to form a rotor or stator lamination bundle. Furthermore, a rotating electrical machine stator having improved heat dissipation due to the insertion of a silicon rubber sheet between a stator core and the stator windings is disclosed by U.S. Pat. No. 6,525,437, issued to Ozawa et al. in 2003. 
   High efficiency generators for powering motor vehicles are described in several devices and include: U.S. Pat. No. 3,845,835, issued to Earl W. Petit in 1974, and U.S. Pat. No. 4,348,628, issued to Loucks in 1982. 
   W.I.P.O Patent No. 03/012955, published in 2003, discloses a stator assembly for an electric rotating machine having a plurality of annular laminated core sections with an extending coolant duct provides increased cooling efficiency. 
   U.S. Pat. No. 5,608,279, issued to Murray (the present inventor) in 1997, discloses a permanent magnet generator with an improved rotor and stator. The &#39;279 patent discloses a rotor having a pair of diametrically opposed magnet groups, each group consisting of curved magnets of unequal flux strength. Furthermore, at any one time only one set of magnets and stators is in alignment. 
   Japanese Patent No. 2002-272072, published in 2002, discloses a DC generator having a rotor having multiple two-pole magnets aligned along the rotor. A single stator is disclosed having armature windings around an integral number of three poles. The armatures are individually provided with a rectifier allowing the DC outputs of each winding to be obtained without need for a commutator or a brush. 
   U.S. Patent Application Publication 2002/0195900, published in 2002, shows a stator construction that utilizes a single piece of metal. In addition, W.I.P.O. Patent No. 02/099950, published in 2002, describes a rotor with magnets mounted at even intervals around the rotor. 
   The technology utilized in motors is similar to that of electric generators and includes a rotor and stationary windings. U.S. Pat. No. 4,751,415, issued to Kitamori et al. in 1988, discloses a brushless DC motor comprising a stator with plural exciting windings and a rotor made of a permanent magnet provided with a compensation winding wound in the stator and compensation magnetic poles disposed on the rotor. U.S. Pat. No. 4,237,397, issued to Mohr et al. in 1980, discloses a permanent magnet stator having two permanent magnet segments formed in an arc, each segment further comprising two subsegments. 
   U.S. Pat. No. 4,112,230, issued to Mohr in 1978, discloses an elongated magnet structure having zones of different magnetic properties for use in electric dynamos. 
   None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus an improved power unit solving the aforementioned problems is desired. 
   SUMMARY OF THE INVENTION 
   The present invention is a permanent magnet electric generator which seeks to increase the efficiency of the generator by improving upon the rotor and stator. The present invention includes a rotor assembly having a plurality of ferromagnetic bars disposed in spaced apart relation about the circumference of a non-magnetic, annular rotor body circumferentially surrounded by an even plurality of stator rows uniformly distributed within a housing disposed around, and arranged normal to, the rotor assembly. 
   Preferably, the rotor assembly includes an even number of diametrically opposing magnets, adjacent magnets presenting opposite poles sequentially to the stators. 
   Each stator row has a plurality of interconnected stators, each stator comprising a combination of ferromagnetic core material, windings and insulation, having at is center a non-conductive planar base member sandwiched between two ferromagnetic planar members. Two layers of insulation are wrapped around the ferromagnetic planar members. 
   The stator is built up by applying a repeating pattern of layers, beginning with a winding of a single filament conductor in one direction around the underlying insulation layers and extending the length of the base member. An insulation layer is then applied and a second winding wound in the opposite direction. Two layers of insulation are next applied, and a band of ferromagnetic material, serving as a concentric core, is wrapped circumferentially around the double layers of insulation, completing the repeating pattern. 
   The stator is then built up by repeating the above pattern of windings, insulation, and cores in concentric fashion. Each winding is formed from a continuation of the previous winding, so that only one filament is employed to wind each stator. Core members are thus interspersed between every other winding, rather than being concentrated in the center of the stator. Two more insulation layers are wrapped around the last core layer and a final primary winding is wound around the insulation. A single insulation layer completes the buildup of the stator. An odd number of windings ensures that the two ends of the conductor extend from opposite sides of the stator, one end extending from the innermost winding, and the second end from the outermost winding. 
   Each stator is wired to the adjacent stators in a predetermined pattern. Every eight stators in a row are wired in parallel, such that the interconnected ends of the inner windings and the interconnected ends of their outer windings are presented to the adjacent groups of stators. Each group of eight stators is then wired in series with the next group, the outermost winding of one group being wired to the innermost windings of the next group. Each stator can supply a specific amount of current at a specific voltage, depending upon the construction of the stator and the rotational force of the magnet passing in front of the distal end of the stator. Parallel-wired stators increase the current producing capability of the generator, while the serially connected groups add voltage potential to the total output of the generator. A row of interconnected stators has two wires extending from it, one wire extending from the innermost winding of the first stator of the row, and a second wire extending from the outermost winding of the last stator. 
   Based upon the scientific principle that moving magnets create electric currents in closed circles of wire, electric energy is generated when the shaft of the rotor, rotationally coupled to a source of rotational energy, is rotated at high speed within the surrounding rows of stators. The rotor is potted in epoxy and banded circumferentially with wire to help retain the magnets in place at high rotational speeds. 
   Accordingly, it is a principal object of the invention to provide a more efficient electric generator. 
   It is another object of the invention to form a generator stator by adding successive layers of a repeating arrangement of windings, insulation, and magnetizable material. 
   It is a further object of the invention to provide a generator rotor wherein diametrically opposing magnets simultaneously present the same magnetic polarity to their respective stators. 
   Still another object of the invention is to provide a multi-phase electric generator with multiple output configurations. 
   It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 

   
     These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front elevation view of a permanent magnet electric generator according to the present invention, shown partly in cross section. 
       FIG. 2A  is a perspective, exploded view of an permanent magnet electric generator according to the present invention. 
       FIG. 2B  is a side elevation view showing two rows of diametrically opposing stators and the housing supporting the rows of stators. 
       FIG. 3  is a perspective view of a stator according to the present invention, partly broken away to reveal several layers. 
       FIG. 4  is a side cross sectional detail view of the stator, drawn along lines  4 — 4  of  FIG. 3 , drawn to enlarged scale. 
       FIG. 5  is a top cross sectional detail view of the stator, drawn along lines  5 — 5  of  FIG. 3 , drawn to enlarged scale. 
       FIG. 6  is a side representative view of one pair of diametrically opposite rows of stators electrically connected according to the present invention. 
       FIG. 7  is a top cross sectional detail view of one row of stators, drawn along lines  7 — 7  of  FIG. 6 , drawn to enlarged scale. 
       FIG. 8  is a front elevation view of the present invention showing generally, the electrical connection between the rows of stators according to the present invention. 
   

   Similar reference characters denote corresponding features consistently throughout the attached drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present invention is a permanent magnet electric generator, designated generally as  100  in the drawings. With reference to  FIG. 1 , the generator  100  is seen to include a rotor assembly  102  and three pairs of diametrically opposed rows of stators  104  arranged radially about rotor  102 , all enclosed in a housing  116 . The present embodiment, having three pairs of stator rows, has a three-phase voltage output, the actual voltage dependent upon the number of stators in each row and the rotational force of the rotor assembly  102 . The precise number of stators  104  and can be varied to influence the output characteristics of generator  100  as desired. 
   The stators  104  comprising a row of stators are held in alignment by a pair of braces  110  epoxied to the stators  104 . Each row of stators is firmly secured to housing  116  by epoxy potting  114 , or by any suitable method. The stators  104  are mounted such that the proximal end  128  of each stator  104  is in close proximity to rotor assembly  102  at a fixed or static location within generator  100 . 
   As best shown in  FIG. 2A , rotor assembly  102  includes a central shaft  118 , an annular body  108  comprised of non-ferromagnetic material, and four pairs of diametrically opposed bar magnets  106  mounted normal to the circumference of the the annular body  108 . The length of the rotor assembly  102  and of the magnets  106  mounted thereto, may be quite long, and is of a length approximately equal to the encircling rows of stators  104 . The magnets  106  are epoxy potted  126  to the body and banded circumferentially with wire  202  to help retain the magnets  106  in place at high rotational speeds. The precise number of magnets  106  within a row is not important beyond a manufacturing concern, provided the polarity of the magnets  106  are in proper alignment and the length of the row of magnets is sufficient to energize the row of stators  104 . 
   For the purposes of this disclosure, a row of magnets will be addressed as a single bar magnet  106 , each magnet having a north pole and a south pole in alignment with a radius of the rotor assembly  102 , such that adjacent magnets about the circumference of the rotor assembly  102  have outward facing poles of alternating polarity. 
     FIGS. 2A and 2B  best illustrates the relationships among rotor assembly  102 , stators  104 , and the housing formed by a plurality of aluminum plates  116  uniformly spaced along the longitudinal axis of the rows of stators  104 . The rows of stators are affixed to the inner edge  132  of a circular opening  112  cut in the middle of the plurality of housing plates  116 . Also shown are shaft  118 , which is common to both rotor  102  and to a source of high-speed rotational force such as a turbine (not shown) powered by gas, water, electric, or other source of energy. Also shown in  FIG. 2A  are leads A 1 , A 2 , B 1 , B 2 , C 1 , C 2  extending from stator row windings to be further explained hereinafter. 
   As shown in  FIG. 3 , each stator  104  has a proximal end  130  and a distal end  128  defining a longitudinal axis arranged normal to the rotational axis R of rotor  102 , and conductor  320  that terminates at two ends  310 ,  312 , for wiring to adjacent stators. Each stator is built upon successive layers, the outermost four layers of each stator  104  comprising an outer layer of insulation  302 , a next winding of conductive wire  304 , and two layers of insulation  306 ,  308  covering in turn the layers underneath. 
     FIGS. 4 and 5  illustrate the preferred construction of a stator  104 . A flat, non-conductive member  402  such as aluminum serves as a core against which two ferromagnetic metal plates  404 ,  406 , of the same approximate size as the base member  402 , abut each side of the base member  402 . Two layers of insulation  408 ,  410  are then wrapped around the underlying metal layers, forming a base or foundation for winding conductor  320 . Starting at stator proximal or outer end  128 , conductor  326  is wound around insulating layer  410  in the direction of the stator distal or inner end forming a layer of windings  412 . This innermost primary winding  412  is covered with a layer  414  of insulation. Conductor  320  is passed over insulation layer  414 , and is then wound around insulation  414  to form a second primary winding  416  extending from the stator distal end  130  back to proximal end  128 . A double layer  418 ,  420  of insulation is then placed over second primary winding  416 . It will be appreciated that conductor  320  of each stator is a single conductive filament. A continuous layer of ferromagnetic core material  422  is then placed around insulation layer  420 , circumferentially surrounding the underlying layers. 
   First and second primary windings  412 ,  416 , combined with layer of ferromagnetic material  422 , and associated insulation layers  408 ,  410 ,  414 ,  418 ,  420  comprise a repeating core assembly  424 , forming a building block for a stator  104  having a plurality of concentrically arranged successive core assemblies  424 .  FIGS. 4 and 5  illustrate a stator  104  constructed from five successive core assemblies  424  which are circumferentially surrounded by two insulating layers  308 ,  306 , a final winding layer  304 , and final insulating layer  302 . An odd number of winding layers, eleven in the present embodiment, ensure that end  312  of conducting wire  320  extends from the distal end  130  of final winding layer  304 . 
   The leads  310 ,  312  of the intra-row stators are wired in a predetermined pattern based upon the desired output characteristics of the generator  100 .  FIGS. 6-8  illustrate the electrical interconnection of a preferred generator  100  having six stator rows, each stator row having forty-eight stators  104 . 
     FIG. 6  illustrates two diametrically opposed stator rows  102 ,  122  interconnected with jumper wire  602  serially connecting lead  312  extending from the distal end of the last stator in one row  120  to lead  310  extending from the proximal end of the last stator in opposing row  122 . The output voltage generated from the diametrically opposed rows  120 ,  122  is presented on leads A 1 , A 2 . 
   As shown in detailed view  FIG. 7 , stators are arranged in groups  606  of eight stators  104 , the eight stators are wired in parallel, their distally extending leads  312  wired in common, and their proximally extending leads  310  wired in common. Adjacent stator groups  606  are interconnected with a series connection  604 , a distally extending lead  312  of one group connecting to a proximally extending lead of the next group. 
     FIG. 8  illustrates the electrical connectivity associated with the three pairs of stator rows, the two rows of each pair interconnected by a jumper wire  602 ,  802 ,  804 . Finally, the output of the generator being presented on three pairs of leads A 1 -A 2 , B 1 -B 2 , C 1 -C 2 . 
   It will be apparent to those of skill in the art that the number of stators  104 , magnets  106 , and winding and core units  424  may be varied to suit the desired characteristics of generator  100 . Furthermore, the relative size and precise configuration of these elements may similarly be varied. 
   It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.