Abstract:
An improved air core homopolar generator is provided. The improved homopolar generator employs a stator having an outer ring for bifurcating magnetic flux flow and multiple flux focusing magnets arranged around a common axis. The improved homopolar generator also includes an inner flux transmitter coaxial with the common axis.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is related to, claims the earliest available effective filing date(s) from, and incorporates by reference in its entirety all subject matter of the following listed application(s) (the “Related Applications”) to the extent such subject matter is not inconsistent herewith; and the present application also claims the earliest available effective filing date(s) from, and also incorporates by reference in its entirety all subject matter of any and all parent, grandparent, great-grandparent, etc. applications of the Related Application(s) to the extent such subject matter is not inconsistent herewith: 
         [0002]    U.S. patent application 61/773,960, entitled “DC Homopolar Generator with Drum Wound Air Coil Cage and Radial Flux Focusing”, naming Robert T. Mandes as inventor, filed 7 Mar. 2013. 
     
    
     BACKGROUND 
       [0003]    1. Field of Use 
         [0004]    This invention relates to an improved homopolar generator. More specifically, the invention relates to an improved direct current homopolar generator with flux condensing. 
         [0005]    2. Description of Prior Art (Background) 
         [0006]    Homopolar machines, and in particular generators, differ from other machines in that the armature conductors are arranged with respect to the magnetic flux path such that the armature conductors will always cut across or intersect the magnetic field in the same direction. Thus, in the case of homopolar generators, a direct current may be generated, without the need of commutators. 
         [0007]    A simple prior art homopolar generator  10  is shown in  FIG. 1 . This generator  10  utilizes a disc  12  rotating on its axis and intersecting the magnetic flux path  14 . The magnet  15  forms the magnetic flux path  14  and generates the magnetic flux φ. It is known that the rotation of the disc  12  in this manner generates an electrical potential between radially distinct portions of the disc  12  while there is magnetic flux passing through the magnetic flux path  14 . In particular, an electrical potential will be induced between the center  16  of the disc  12  and the circumference  18  of the disc. In  FIG. 1 , the electrical energy thus generated is removed by means of brushes  20  and  22 . 
         [0008]    In other prior art devices, a conducting drum  24  is used in place of a disc  12 , as shown in  FIG. 2 . The conducting drum  24  rotates on its longitudinal axis and intersects the magnetic flux path  26  thereby generating an electrical potential between axially distinct portions on the drum  24  and in particular between the ends  28 ,  30 . The magnetic flux path  26  is defined by the core  25  which has a low magnetic reluctance. The magnetic flux is generated by the exciting winding  27 . Since the drum  24  is rotating, the electricity is removed by means of brushes  32 ,  34  located near the ends  28 ,  30 , similar to the case of the disc  12 . 
         [0009]    Homopolar inefficiencies, most importantly, also include: 1.) Produces only “current” and very little controlled “voltage” due to the absence of “coils”, etc. Also the current produced may be greatly reduced due to resistance of commutation, etc., 
         [0010]    One of the disadvantages associated with conventional homopolar machines is the magnetic flux φ tends to be uniformly shaped resulting in magnetic leakage flux which does not cross the air gap and link the stator winding, thus providing no useful magnetic field. 
         [0011]    Another disadvantage with conventional homopolar machines is the efficiency of the machine is significantly reduced by the effects of eddy currents associated with non air core generators. 
       BRIEF SUMMARY 
       [0012]    The foregoing and other problems are overcome, and other advantages are realized, in accordance with the presently preferred embodiments of these teachings. 
         [0013]    In accordance with one embodiment of the present invention a direct current homopolar generator is provided. The DC homopolar generator includes a conjoined toroid shaped armature, wherein the conjoined toroid shaped armature is magnetic and generates focused unidirectional magnetic flux lines. In addition the DC homopolar generator includes an electrically conductive, coreless, wire coil cage disposed within the conjoined toroid shaped armature, wherein the unidirectional magnetic flux lines are substantially perpendicular to the electrically conductive wire coil cage. 
         [0014]    The invention is also directed towards a stator having an outer ring for bifurcating magnetic flux flow and curved magnets adjacent an inner curve of the outer ring. An inner flux transmitter enables magnetic flux flow between the curved magnets and across air gaps wherein conductors are rotated through the air gaps and bisect the magnetic flux at substantially 90 degrees. 
         [0015]    In accordance with another embodiment the invention is also directed towards a direct current homopolar which includes a stator structure. The stator structure includes an outer ring for bifurcating and conducting magnetic flux. The outer ring includes an inner surface and a first outer magnet having first and second opposing surfaces, wherein the first opposable surface is attachable to the inner surface of the outer ring. Attachable to the second opposable surface of the first outer magnet is an outer ferrous concave cap. On the opposite side of the ring there is a similar arrangement. In the center of the ring is a ferrous shaft bearing and inner magnets for continuing the flux path across the center of the stator structure and around a drive shaft. The inner and outer magnets are capped with convex and concave surfaces as suitable to shape the magnetic flux path across a gap between the inner and outer magnets. Also included is a rotor structure comprising a plurality of conductive windings where each winding is adaptable to rotate through the gaps in a plane substantially orthogonal to the magnetic flux plane. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0017]      FIG. 1  is an illustration of a prior art homopolar generator having a disc shaped armature; 
           [0018]      FIG. 2  is an illustration of a prior art homopolar generator having a drum shaped armature; 
           [0019]      FIG. 3  is an illustration of a homopolar generator having a drum shaped armature and magnetic flux path focusing features in accordance with one embodiment of the present invention; 
           [0020]      FIG. 4  is an illustration of a homopolar generator having a conjoined toroid shaped armature and magnetic flux path focusing features in accordance with another embodiment of the present invention; 
           [0021]      FIG. 4A  is a close up illustration of the homopolar generator having a conjoined toroid shaped armature and magnetic flux path focusing features shown in  FIG. 4 ; 
           [0022]      FIG. 5  is a diagram of the magnetic flux resulting from the armature shown in  FIG. 3 ; 
           [0023]      FIG. 6  is a pictorial cross section of an end view of the coil cage shown in  FIG. 4 ; 
           [0024]      FIG. 7  is an illustration of a homopolar generator having a drum shaped armature and magnetic flux path focusing features in accordance with an embodiment of the present invention shown in  FIG. 3 ; 
           [0025]      FIG. 8  is an illustration of a 120 degree version of the homopolar generator having a drum shaped armature and magnetic flux path focusing features in accordance with an embodiment of the present invention shown in  FIG. 3 ; and 
           [0026]      FIG. 9  is an illustration of a homopolar generator having a drum shaped armature in accordance with an embodiment of the present invention shown in  FIG. 3   
       
    
    
     DETAILED DESCRIPTION 
       [0027]    The following brief definition of terms shall apply throughout the application; 
         [0028]    The term “comprising” means including but not limited to, and should be interpreted in the manner it is typically used in the patent context; 
         [0029]    The phrases “in one embodiment,” “according to one embodiment,” and the like generally mean that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present invention, and may be included in more than one embodiment of the present invention (importantly, such phrases do not necessarily refer to the same embodiment); 
         [0030]    If the specification describes something as “exemplary” or an “example,” it should be understood that refers to a non-exclusive example; and 
         [0031]    If the specification states a component or feature “may,” “can,” “could,” “should,” “preferably,” “possibly,” “typically,” “optionally,” “for example,” or “might” (or other such language) be included or have a characteristic, that particular component or feature is not required to be included or to have the characteristic. 
         [0032]    Referring now to  FIG. 3  there is shown an illustration of a section of a homopolar generator having, a drum shaped armature and magnetic flux path focusing features in accordance with the present invention. For clarity the coil cage  31  is shown off set along the center shaft  36 . It will be understood that during operation the coil cage  31  is centered along center shaft  36  such that magnetic flux as discussed herein bisects coil cage  31  at substantially 90 degrees. It will also be understood that the stator and/or armature of the present invention may be rotated independently around a common axis. 
         [0033]    Still referring to  FIG. 3 , there is shown a symmetrical magnetic flux path φ flowing through magnetic flux assembly generator  310 . The magnetic flux generator assembly  310  includes: outer ring assembly  37 , neodymium magnet  38 , ferrous concave cap  38 A, ferrous convex cap  39 A, neodymium magnet  39 , ferrous shaft bearing  311 , neodymium magnet  312 , ferrous convex cap  312 A, ferrous concave cap  313 A, and neodymium magnet  313 . It will be appreciated that outer magnets  38  and  313  are advantageously larger than inner magnets  39  and  312  to obtain optimal radial focusing of magnetic flux. In addition, the outer ferrous ring assembly  37  is substantially one half the widths of the two outer magnets  38  and  313  in order to facilitate the magnetic flux path. 
         [0034]    Still referring to FIG,  3 , it will be understood that concave cap  38 A and convex cap  39 A are shaped to be the inverse shape of the other. It will also be understood that the degree of concavity of concave cap  38 A and the corresponding degree of convexity of the convex cap  39 A may be any suitable degree. It will also be appreciated that the concave cap  38 A focuses the magnetic flux emanating from neodymium magnet  38  across air gap  38 B onto convex cap  39 A. The magnetic focusing action of the concave and convex caps,  38 A and  39 A, respectively, across air gap  38 B helps to minimize flux leakage. It will also be appreciated that neodymium magnet  38 A may be any suitable size or shape. Similarly, neodymium magnet  39  may be any suitable size or shape. 
         [0035]    Still referring to  FIG. 3 , ferrous shaft bearing  311  may be any suitable ferrous material necessary to complete the flux path. Ferrous shaft bearing  311  may be a suitable hybrid device where the ferrous shaft bearing  311  is magnetically isolated from the center shaft  36  in order to minimize flux leakage. 
         [0036]    In alternate embodiments the ferrous shaft bearing  311  may be a solid magnet suitably shaped to match the contours of outer concave magnets  38  and  313  and any associated caps, if any. 
         [0037]    Center shaft  36  may be any suitable diameter or length and may comprise any suitable material. Center shaft  36  may be ferrous or non-ferrous material. 
         [0038]    Still referring to  FIG. 3 , neodymium magnet  312  continues the magnetic flux path from shaft bearing  311 . Attached to neodymium magnet  312  is convex ferrous cap  312 A. Ferrous cap  313 A, attached to neodymium magnet  313 , focuses the magnetic flux emanating from neodymium magnet  312  across air gap  312 B. The magnetic focusing action of the convex and concave caps,  312 A and  313 A, respectively, across air gap  312 B helps to minimize flux leakage. Neodymium magnet  313 , connected to outer magnetic ring assembly  37  completes the magnetic flux path. It will be appreciated that magnets, gaps, caps, and outer ring are all substantially coplanar to facilitate the flow of magnetic flux φ. 
         [0039]    Outer magnetic ring. assembly  37  may be any suitable ferrous material or structure capable of supporting a bifurcated magnetic flux path. 
         [0040]    The two larger outer permanent neodymium magnets  38 ,  313  mounted 180 degrees “off-set” internally on the outer 1018 steel magnetic field circuiting ring  37 . The outer 1018 steel magnetic field circuiting ring  37  may be held “static” and locked in place concentrically on and relative to the “static” central axis drive shaft  36  which may be mounted between two “shaft-locking” base mounted ball bearings. 
         [0041]    The two smaller inner core permanent neodymium magnets  39 ,  312  mounted 180 degrees “off-set”, (and are pole oriented North to South and in line with the two 180 degrees “off-set” larger outer permanent neodymium magnets  38 ,  313 ), on the outer circumference of the inner 1018 steel magnetic field circuiting ring  311  which may he “press-fitted” with an inner needle bearing on the “static” central axis drive shaft  36 . 
         [0042]    Also shown in  FIG. 3  is coil cage  31 . Coil cage  31  is an independent individually drum wound air coils gathered together tightly centrally as to cover the entire 360 degree circumference of the drum with minimal gaps as discussed herein in order to ensure the optimal mutual induction between the coils within the output circuit. Each set of individual coil leads are connected to opposing bar segments of a 48 bar mica molded commutator-commutated top and bottom by separate carbon brushes (not shown). Coil cage  31  may comprise any suitable type of wire material, such as, for example, copper; and, any suitable gauge. 
         [0043]    Still referring to  FIG. 3 , it will be understood that coil cage  31  may be held stationary while outer magnetic ring assembly  37  is rotated; or, that coil cage  31  may be rotated while outer magnetic ring assembly  37  is held stationary; or, both coil cage  31  and outer magnetic ring assembly  37  are both rotated in opposite directions. 
         [0044]    It will also be appreciated that there may be any suitable number of magnetic flux generator assembly  310 ; and, that each magnetic flux generator assembly  310  may be independent of the other assemblies. 
         [0045]    Referring also to  FIG. 4 , there is shown an illustration of a homopolar magnetic flux generator assembly  410  having a conjoined toroid shaped armature  45  and magnetic flux path focusing features in accordance with the present invention. The homopolar magnetic flux generator assembly  410  includes coil cage  44  extending through conjoined toroid shaped armature  45  and surrounding magnetic core  44 A; drive gear  42 ; and bearing  46 . Magnetic core  44 A may be any suitable magnetic core material such as, for example, a rare earth magnet core. In addition, magnetic core  44 A may comprise a homogenous magnetic core or comprise a suitable hybrid magnetic core, including, for example, rare earth magnets and other suitable magnetic materials. Also included in the homopolar magnetic flux generator assembly  410  shown in  FIG. 4  are pillow block bearings  41  and  47 ; and drive shaft  43 . It will be understood that drive shaft  43  may be any suitable ferrous or non-ferrous material. 
         [0046]    Referring also to  FIG. 4A  there is shown a close up illustration of the homopolar magnetic flux generator assembly  410  having a conjoined toroid shaped armature  45  and magnetic flux path focusing features shown in  FIG. 4 . As shown in  FIG. 4 , flux lines  46  are focused and nearly all perpendicular to coil cage  44  as the flux lines  46  cross air gap  46 A. It will be appreciated that the novel shape of the conjoined toroid shaped armature focuses the magnetic flux lines  46  such that the efficiency of the magnetic flux generator assembly  410  is improved over a conventional air core generator. It will be further appreciated that the highly efficient magnetic flux generator assembly  410  disclosed herein avoids, or minimizes, many of the problems associated with magnetic cores such as eddy currents and hazardous noise due to magnetostriction. 
         [0047]    Referring also to  FIG. 5 , there is shown a diagram of the magnetic flux resulting for the homopolar generator shown in  FIG. 3 . It will be appreciated that the focused flux lines  51  are substantially perpendicular across gaps  52 ,  53  through which coil  31  turns, thereby minimizing flux leakage and maximizing induced EMF. 
         [0048]    Still referring to  FIG. 5  it can be seen how inner 1018 steel magnetic field circuiting ring  311  channels the flux  55  around center shaft area  54  and refocuses flux lines to cross gap  52 . it will be appreciated that inner 1018 steel magnetic field, circuiting ring  311  may be any suitable material and shape for channeling and focusing magnetic flux lines  51 . 
         [0049]    Referring also to  FIG. 6 , there is shown a pictorial cross section view of a portion  61  of the coil cage shown in  FIG. 3  or  FIG. 4 . in  FIG. 4  coil cage  44  is comprised of a suitable number of windings longitudinally wrapped such that each winding is parallel to the axis of the magnetic core  44 A and perpendicular to the magnetic flux lines  46 . In addition each winding may comprise a suitable conductor such as copper or aluminum; and, each winding may be suitably shaped to optimize the flux conductor interaction. For example, the conductor  63  may be round such as a typical wire, or any other suitable shape such as rectangular. 
         [0050]    Similarly, in  FIG. 3  coil cage  31  is comprised of a suitable number of windings longitudinally wrapped such that each winding is parallel to the axis of rotation of shaft  36  and perpendicular to the magnetic flux lines shown in  FIG. 3 . In addition each winding may comprise a suitable conductor such as copper or aluminum; and, each winding may be suitably shaped to optimize the flux conductor interaction. For example, the conductor  63  may be round such as a typical wire, or any other suitable shape such as rectangular. 
         [0051]    Still referring to  FIG. 6 , it will be appreciated that there may be any number of winding layers  66 ,  67 , and  68 . Also, gaps  62  between windings  63  in any particular layer are gaps resulting from an insulating coating surrounding the winding  63 . In addition, no gap  62  in any one layer would align with a gap  62  in any other layer, above or below. It will be appreciated that the minimal gap  62  between windings and the staggered gap pattern minimizes leakage flux. 
         [0052]    Also shown in  FIG. 6  are angles X and thickness  65 ; both of which are determined by a process similar to determining wire gauge and number-of-turns per coil cage unit attached to one set of commutators. 
         [0053]    Referring also to  FIG. 7  there is shown a top down illustration of a homopolar generator having a drum shaped armature and magnetic flux path focusing features in accordance with an embodiment of the present invention shown in  FIG. 3 . Flux lines  71  are radially focused along focusing axis paths AD and BC. It will be appreciated that focusing flux lines  71  in this manner maximizes the orthogonal aspect of the flux lines  71  interacting with coil cage  72 . It will also be appreciated that the curvature of coil cage  72  may be substantially similar to the curvature of ferrous concave cap  38 A, ferrous convex cap  39 A, ferrous convex cap  312 A, and ferrous concave cap  313 A to maximize the flux  71  conductor (coil cage  72 ) interaction and minimize leakage. 
         [0054]    Still referring to  FIG. 7 , inner 1018 steel magnetic field circuiting ring  74  may be any suitable material and shape for channeling and focusing magnetic flux lines around center shaft ( 36  in  FIG. 3 ). 
         [0055]    It will also be appreciated and understood that Outer magnetic ring assembly  73  may be any suitable ferrous material or structure capable of transmitting and/or focusing magnetic flux  71 . 
       120 Degree Applied Magnetic Field Design 
       [0056]    Referring also to  FIG. 8  there is shown  FIG. 8  an illustration of a 120 degree assembly  80  of the homopolar generator having a drum shaped armature and magnetic flux path focusing features in accordance with an embodiment of the present invention shown in  FIG. 3 . 
         [0057]    The assembly  80  may comprise one or more of operation: (b  1 .) a “Stator” mode where either the rotor coil  83  is rotated while the stator assembly (e.g., magnets  84 , 85 , ring  81  and ring  82 ) is held stationary with respect to the rotor; or (2.) both the rotor coil and the stator assembly are counter-rotated at the same time. 
         [0058]    The two outer 120 degree permanent neodymium magnets  84 ,  85  may be mounted 180 degrees “off-set” internally on the outer 1018 steel magnetic field circuiting ring  81 , the one inner core permanent neodymium magnet  82  as one solid piece with 120 degree north and south poles, (with no shaft through its center) is pole aligned North to South with outer magnets  84 ,  85 . It will be appreciated that two outer magnets may be and suitable arc length or curvature, such as, but not limited to 120 degrees. Likewise inner core permanent neodymium magnet  82  may he any suitable matching curvature or arc. For example, arc AD and arc EH as shown in  FIG. 8 . 
         [0059]    Still referring to  FIG. 7  and also  FIG. 8 , it will be understood that rotor  83  in  FIG. 8  and rotor  72  in  FIG. 7  are drum wound rotors, (e.g., covering the entire 360 degree circumference with substantially no “gaps” between the tightly gathered windings). 
         [0060]    Referring also to  FIG. 9  there is shown an illustration of a homopolar generator haying a drum shaped armature in accordance with an embodiment of the present invention shown in  FIG. 3 . The homopolar generator includes the flux assembly generator  310 . The magnetic flux generator assembly  310  includes: outer ring assembly  37 , neodymium magnet  38 , ferrous concave cap  38 A, ferrous concave cap  313 A, and neodymium magnet  313 . It will be appreciated that outer magnets  38  and  313  are advantageously larger than inner magnets ( 39  and  312  shown in  FIG. 3 ) to obtain optimal radial focusing of magnetic flux across coil cage  31 . In addition, the outer ferrous ring assembly  37  is substantially one half the widths of the two outer magnets  38  and  313  in order to facilitate the magnetic flux path. 
         [0061]    Also shown in  FIG. 9  is timing or sprocket gear  92 . Sprocket gear  92  may be used to rotate coil cage  31  within flux generator assembly  310 . It will be appreciated and understood that there may be more than one sprocket gear for turning flux generator assembly  310  while coil cage  31  is rotated relative to the flux generator assembly, e.g., an opposite rotation. 
         [0062]    It should be understood that the foregoing description is only illustrative of the invention. Thus, various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims. 
         [0063]    It will be appreciated that eddy currents in cores or in ferrous magnetic materials in close proximity to induction coils such as found in the prior art have been substantially eliminated in the present invention. 
         [0064]    In addition, another advantage is its output is not unlike that of a battery, (the closest thing to an “Ideal Voltage Source”), in that the output voltage is substantially constant under “load resistance”.