Abstract:
The present invention provides a module dual radial gap brushless, permanent magnet AC or DC (BLPMAC/BLPMDC) rotary electrical motor/generator suitable for direct drive wind or other fluid medium driven turbines. The motor/generator includes a circular rotor ring of individual rotor segments and a circular stator ring of individual stator segments. Each rotor segment includes a plurality of magnet modules disposed therein and arranged in alternating magnetic plurality. The stator includes a plurality of stator induction modules nested within the rotating rotor. Each stator induction module includes a coil electrically connected to a phase bus bar and a common bus bar. In a first embodiment of the stator induction modules, the motor/generator has a pre-established, fixed gap between the magnets and the coils. In a second embodiment of the stator induction modules, the generator has a gap controlled by a self-calibrating mechanism that compensates for variations in dimensional tolerance and concentricity between the rotor and the stator.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a completion application which claims the priority benefit of co-pending U.S. Provisional Patent Application Ser. No. 62/303,734, filed Mar. 4, 2016, titled “Segmented Dual Radial Gap Brushless PMDC Motor/Generator,” the entire disclosure of which, including the drawing, is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates generally to brushless, permanent magnet AC or DC rotary electrical motor/generators (BLPMAC/BLPMDC) machines used to convert a rotational mechanical power input into an electrical power output. More particularly, the present invention concerns modular BLPMAC/BLPMDC generators for use in direct drive applications. Even more particularly, the present invention relates to modular BLPMAC/BLPMDC motor/generators comprising individual modular segments for manufacturing with wind turbines. 
         [0004]    2. Description of the Prior Art 
         [0005]    As is known to those skilled in the art, a wind turbine generator employs a rotor that incorporates a series of blades designed to capture wind energy and transform it into rotational mechanical power that is coupled to an electrical generator for the purpose of producing renewable electric energy. The turbine rotors in larger wind turbine systems (1 megawatt and above) typically rotate at relatively low RPM&#39;s and produce high levels of torque. 
         [0006]    The output power produced by an electrical generator is proportional to the rotational speed of the generator rotor, which is governed by the rotational speed of the turbine rotor blades relative to the wind velocity. 
         [0007]    Conventional generators, regardless of the type, used in most large wind or other large, low RPM fluid medium driven applications, employ a gearbox positioned between and operatively connected to both a turbine rotor shaft and the generator. This is for the purpose of increasing, or “gearing-up,” the rotational speed of the generator relative to that of the turbine that drives it in order to attain a rotational velocity suitable for the generation of the desired power. 
         [0008]    The gearbox is the single most expensive component in a wind turbine system. Because of the loads imposed on it, it is also the component most likely to fail and, typically, generates the system&#39;s highest maintenance cost. 
         [0009]    Brushless, permanent magnet DC (BLPMDC) generators are an advantageous option for use in a wind turbine system. Since they have only one moving part, i.e. the rotor. Also, BLPMDC generators have been shown to endow a system with a combination of high efficiency and relatively maintenance free operation. When employed in a direct drive application, they eliminate the need for a gear box. 
         [0010]    Although there are substantial capital expense and maintenance cost benefits to be gained from eliminating the gearbox, there are also significant drawbacks. Power is produced in proportion to the rate at which the permanent magnets in the rotor move past the coils in the stator. This is a function of the rotational speed (RPM) in combination with the diameter of the generator. In a large wind turbine system, the generator, lacking the benefit of any intermediary gearing, will rotate at the same low RPM as the turbine blades. The speed at which the magnets in a BLPMDC system move past the generator stator coils at any specific RPM increases linearly in relation to the diameter of the motor. 
         [0011]    Therefore, increasing the diameter of the generator can provide the velocity necessary to produce substantial amounts of power. However, the sheer size required of a directly driven BLPMDC generator with the capacity to produce power in excess of 1 megawatt has, in the past, eliminated this approach from consideration. 
         [0012]    Furthermore, along with increased size comes a number of other ancillary issues, not the least of which is the problem associated with transporting a large diameter machine to a final, typically remote, site for installation. Because of this, direct drive BLPMDC generators have historically been considered unsuitable for high power use and, therefore, employed only in smaller, higher RPM, low power wind turbine applications. 
         [0013]    As detailed below, the present invention mitigates and overcomes these drawbacks by providing a modular BLPMDC generator suitable for use in a direct drive application for the generation of renewable power well in excess of 1 megawatt. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention provides a modular dual radial gap BLPMDC motor/generator suitable for direct drive wind or other fluid medium driven turbines. Preferably, the motor/generator hereof employs a dual radial gap architecture such as described in U.S. Pat. No. 8,247,943, the disclosure of which is hereby incorporated by reference. 
         [0015]    The present invention, generally, comprises a large diameter, typically greater than 5 feet, two-component circular hoop structure. The first component comprises a circular rotor ring of operatively connected individual rotor segments. The second component comprises a circular stator ring of operatively connected individual stator segments. 
         [0016]    Each rotor segment includes a rotor frame having a top wall and a pair of opposed sidewalls extending downwardly from and substantially perpendicular to opposite ends of the top wall. The top wall and the sidewalls define an interior rotor channel. Each rotor segment further includes a plurality of magnet modules mounted within the rotor channel and arranged in alternating magnetic polarity. Each magnet module includes a substantially U-shaped metal band having a bight section, a pair of legs extending downwardly from the bight section, and a pair of inwardly facing magnets being disposed on respective legs and positioned within the channel. 
         [0017]    Each stator segment includes a stator frame including a base and a pair of opposed sidewalls extending upwardly from and substantially perpendicular to opposite ends of the base. The stator frame further includes a pair of shoulders extending inwardly from respective sidewalls. The base and the pair of sidewalls define an interior stator channel. 
         [0018]    Each stator segment further includes a plurality of phase bus bars and at least one common bus bar disposed within the stator channel. 
         [0019]    Each stator segment further includes a plurality of operatively connected stator induction modules being seated on the shoulder of the stator frame. Each stator induction module includes a coil having leads extending from opposing ends of the coil and at least one turn formed therebetween. Respective leads of each coil is electrically connected one phase bus bar and a common bus bar. 
         [0020]    A molded polymer formed from a thermally, non-electrically conductive polymer at least partially encapsulates the coil. 
         [0021]    In use, the stator is fixed to a base, centered to share the same axis and plane as the rotor, and positioned so that the stator induction modules are nested within the rotating rotor channel. The rotor rotates above the stationary stator such that the plurality of magnet modules encircles the stator induction modules and provides a dual air gap between the coils and the opposing magnets. 
         [0022]    In a first embodiment of the stator induction modules, the motor/generator has a pre-established, fixed gap between the rotor magnets and the coils. 
         [0023]    In a second embodiment of the stator induction modules, the generator has a gap controlled by a self-calibrating mechanism that compensates for variations in dimensional tolerance and concentricity between the rotor and the stator. 
         [0024]    In a third embodiment, the rotor frame is a substantially T-shaped member having a plurality of longitudinal slots formed therein. Instead of the magnet modules described with respect to the above embodiments, a magnet is disposed within each one of the plurality of longitudinal slots and arranged in alternating magnetic polarity. 
         [0025]    Here, the stator includes a plurality of stator induction modules similar to that described above. Additionally, each stator induction module includes a lamination stack formed from a magnetic permeable material having a bight section encircled by the coil and a pair of opposing legs extending upwardly from and substantially perpendicular to opposite ends of the bight section. Thus, the opposing legs of the lamination stack extend upwardly, thereby extending parallel to a respective magnet. 
         [0026]    The modular/segmented design of the motor/generator permits assembling the individual modules into separate segmented rotor and stator sub-assemblies which can be packaged as a kit. 
         [0027]    For a more complete understanding of the present invention, reference is made to the following detailed description and accompanying drawing. In the drawing, like reference characters refer to like parts throughout the several views, in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is a perspective view showing a single magnet module in accordance herewith; 
           [0029]      FIG. 2  is a partial perspective view showing a first embodiment of a rotor segment channel and an array of magnet modules disposed therewithin; 
           [0030]      FIG. 3  is a perspective view showing the relationship between a segment of the rotor and a full array of magnet modules disposed in a multi-segment assembly; 
           [0031]      FIG. 4  is a partial perspective view of a second embodiment of a rotor segment; 
           [0032]      FIG. 5  is a front view of a first embodiment of a coil of a stator induction module in accordance herewith; 
           [0033]      FIG. 6  is a front view of the first embodiment of the coil situated within a dual air gap provided in an associated magnet module; 
           [0034]      FIG. 7  is a perspective view of the first embodiment of the coil partially encapsulated in a thermally conductive molded polymer; 
           [0035]      FIG. 8  is a perspective view of the first embodiment of the coil fully encapsulated; 
           [0036]      FIG. 9  is a perspective view of a second embodiment of the coil encircling a laminated stack of a magnetically permeable metal; 
           [0037]      FIG. 10  is a front view of the second embodiment of the coil positioned within the dual air gap provided in an associated magnet module hereof; 
           [0038]      FIG. 11  is a cut-away view of a first embodiment of the stator induction module partially encapsulated and situated within a stator in accordance herewith; 
           [0039]      FIG. 12  is a cut-away view of the first embodiment of the stator induction module fully encapsulated and situated within the stator in accordance herewith; 
           [0040]      FIG. 13  is a perspective view of a second embodiment of the stator induction module including an upper radial calibration guide and a lower radial calibration guide that serve to calibrate and maintain the fixed dual air gaps between the stator induction modules and the magnet modules hereof; 
           [0041]      FIG. 14  is a perspective view of the second embodiment of the stator induction module seated within a radial calibration guide carrier in accordance herewith; 
           [0042]      FIG. 15  is a bottom perspective view of the second embodiment of the stator induction module of  FIG. 14  showing the end of the coil protruding through the bottom of the radial calibration guide carrier; 
           [0043]      FIG. 16  is a partial perspective view of the second embodiment of the stator induction module of  FIG. 15  positioned within a stator segment and the coil connected to a plurality of bus bars; 
           [0044]      FIG. 17  is a partial perspective view of a stator frame in accordance herewith; 
           [0045]      FIG. 18  is a side view of a plurality of stator segments in accordance herewith; 
           [0046]      FIG. 19  is a perspective view of a wind driven turbine in combination with the motor/generator hereof; 
           [0047]      FIG. 20  is a partial perspective view of an alternative embodiment of the rotor frame; 
           [0048]      FIG. 21  is a perspective view of a plurality of magnets in accordance with this alternative embodiment; 
           [0049]      FIG. 22  is a perspective view of the magnets disposed within the rotor frame of  FIG. 20 ; 
           [0050]      FIG. 23  is a front plan view of the magnets positioned between a stator in accordance herewith; and 
           [0051]      FIG. 24  is a partial perspective view of the combined rotor and stator in accordance with this alternative embodiment. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0052]    Now, with reference to the drawing, and as shown in  FIG. 19 , the present invention provides a motor/generator, denoted at  10 , generally comprising: (a) a rotor  20 ; and (b) a stator  60 . 
         [0053]    As shown in  FIGS. 2, 3, and 19 , the rotor  20  includes an upper rotor ring  22  comprising a plurality of rotor segments  24  connected together in side-by-side in series, which house a plurality of magnet modules  26 . 
         [0054]    Referring to  FIGS. 11, 12, and 18 , the stator  60  includes a fixed lower stator ring  62  comprising a plurality of stator segments  64  connected together in side-by-side in series, which houses a plurality of stator induction modules  66 . The rotor ring  22  is concentric with, and rotates around, the stator ring  62 . 
       I. Rotor 
       [0055]    With regard to the segmented rotor ring  22  shown in  FIG. 3 , as noted above, the rotor ring  22  comprises the plurality of rotor segments  24 , each of which house the plurality of magnet modules  26  mounted therein, as described hereinbelow. 
       1. Magnet Modules 
       [0056]    As shown in  FIG. 1 , each magnet module  26  is a substantially U-shaped member comprising a magnetically permeable metal band  28  having a bight section  32 , a pair of legs  30  extending substantially perpendicular from opposite ends of the bight section  32 , and a pair of opposing magnets  34 . 
         [0057]    Each leg  30  has a free end. The pair of opposing magnets  34  is operatively attached at respective free ends, one on each leg  30 , such as by gluing or the like. The magnets  34  are positioned so that the North pole of one magnet is facing inward on one leg  30  and the South pole of the second magnet is facing inward on the other opposing leg  30 . As noted, a permeable metal alloy such as a silicon steel serves as both a structural member and a flux path to connect the two opposing magnets  34  in a magnetic circuit. The metal band  28  and the magnets  34  cooperate to define the magnet module  26 . 
       2. Rotor Segments 
       [0058]    As shown in  FIGS. 2 and 3 , an array of the magnet modules  26  is arranged in a pattern of alternating magnetic polarity and are at least partially disposed within a grouping of rotor segments  24 . The rotor segments  24 , per se, are formed from a non-magnetically permeable material. 
         [0059]    In a first embodiment of the rotor segments  24 , each rotor segment  24  is a substantially, inverted U-shaped frame member having a top wall  38  and a pair of opposing sidewalls  36  extending substantially perpendicular from opposite ends of the top wall  38 . 
         [0060]    The top wall  38  and opposing sidewalls  36  of each rotor segment  24  define an interior rotor channel  44 . The array of magnet modules  26  is attached to and secured in position to the rotor segments  24 , within the rotor channel  44 , by any suitable method, such as, for example, with mechanical fasteners (not shown) or may be molded in place into a rotor segment  24  made of a structural grade polymer, such as a glass-filled nylon or the like. 
         [0061]    As shown in  FIG. 19 , when assembled, the rotor segments  24  are connected together side-by-side in series in a final ring shaped assembly, this forming the rotor ring  22 . The rotor segments  24  may be operatively connected to one another individually by welding or with mechanical attachments. Alternatively, the rotor segments  24  may be operatively connected to one another by attaching them individually to a separate ring or cylindrical-shaped common frame. 
         [0062]    Referring now to  FIG. 4 , there is shown a second embodiment of a rotor segment  124 . Here, each rotor segment  124  is still a substantially, inverted U-shaped frame member having a top wall  138  and opposing sidewalls  136 . Additionally, each rotor segment  124  further includes an upwardly projecting, hollow protrusion  140  formed in the top wall  138  which defines a slot  142 . The slot  142  accommodates an upper radial calibration guide  186 , as described below. 
       II. Stator 
       [0063]    Referring again to  FIGS. 11, 12, and 18 , as shown, the segmented stator ring  62  houses the plurality of stator induction modules  64 . Each stator induction module  66 , generally, 
         [0064]    In  FIGS. 5 and 6 , there is depicted a first embodiment of the coils  68 , which are deployed in what is denoted as a “slot-less” design. The coils  68  in this first embodiment are formed from a conductive material, typically copper, and include at least one, and, preferably, a plurality of turns  69 . Each coil  68  has leads  70  at opposite ends of the coil  68 . The leads  70  projecting from the coil  68  are strands and flexible in order to accommodate radial motion, as the stator induction module  66  floats radially, to maintain dimensional control of the dual air gaps between the coil  68  and opposing magnets  34 . 
         [0065]    As shown in  FIGS. 7 and 8 , each coil  68  may be partially encapsulated or fully encapsulated, respectively, with a thermally, non-electrically conductive molded polymer  72 . The molded polymer  72  imparts a rigid structure and is configured for attaching the coil  68  to the stator segments  64 , discussed below, and for fixedly positioning the stator segments  64  in an X, Y, and Z plane operating position relative to that of the rotor  20 . 
         [0066]    Additionally, full encapsulation protects each coil  68  from operational and/or environmental contamination. A void  74  is formed in the center of the encapsulated coil  68  and the molded polymer  72  to provide weight reduction. The coils  68  can be encapsulated by any suitable technique known to the skilled artisan. 
         [0067]    Since heat is generated in the coil  68  in an amount proportional to the current passing through a conductor multiplied by its resistance (I 2 R), the molded polymer  72 , at least partially encapsulating the coils  68 , serves as a thermal link to both the stator segments  64  and the surrounding ambient air. 
         [0068]    In an alternative or second embodiment of the coils, a coil  168  is shown in  FIGS. 9 and 10 . This embodiment alleviates the negative effects of the large dual air gap as exhibited between the aforementioned coils  68  and the magnet modules  26 . In this second embodiment, referred to as a “slotted” design, the coil  168  differentiates from the first embodiment of the coil  68  discussed above by providing a stack of soft magnetic material laminations  176 . The lamination stack  176  is a magnetically permeable material such as a silicon steel. 
         [0069]    The coil  168  is wound around the lamination stack  176  which serves to direct and concentrate the flux path of the magnetic circuit. The large dual air gap present in the “slot-less” design is significantly reduced by the presence of the lamination stack  176  and almost completely bridges the dual air gap between the two magnets  34 . This second embodiment of the coils  168  also dramatically increases the power density and efficiency of the present invention by reducing the total air gap that restricts the magnetic flux in the magnetic circuit. The total air gap in this second embodiment is limited to only the sum of the gaps present at either end of the lamination stack  176 . 
         [0070]    Similar to that of the first embodiment of the coil  68 , the second embodiment of the coils  168  may also be either partially or fully encapsulated by the molded polymer.  72   
       2. Stator Induction Modules 
       [0071]    Referring now to  FIGS. 11 and 12 , there is shown a first embodiment of the stator induction module  66  positioned or nested within the rotor channel  44 . Here, the stator induction module  66  is an integrally formed structure comprising the coil  68  and the molded polymer  72 , which either partially encapsulates ( FIG. 11 ) or fully encapsulates ( FIG. 12 ) the coil  68 . As noted above, this first embodiment of the stator induction module  66  may employ either the first or second embodiment of the coil  68  or  168 . 
         [0072]    Referring now to  FIGS. 13-16 , a preferred, second embodiment of a stator induction module  166  is shown in combination with the second coil embodiment  168 , which employs the lamination stack  176 . Here, the stator induction module  166  includes a lower radial calibration guide  180  and a lower radial calibration guide carrier  182  to impart self-calibration with respect to the rotor  20 . This maintains a constant dual air gap by maintaining its position within the rotor channel  44 . 
         [0073]    In this second embodiment, the stator induction modules  166  are shown as being fully encapsulated, but it is to be understood that they may also be only partially encapsulated. 
         [0074]    A molded polymer  172  encapsulates the coil  168  and includes an elongated radial key  178  extending downwardly from the bottom of the molded polymer  172 . The lower radial guide  180  is provided above the radial key  178 , disposed circumferentially around the molded polymer  172 . 
         [0075]    A plurality of calibration rollers  184  is rotatably disposed on the lower radial calibration guide  180  and, optionally, an upper radial calibration guide  186 , discussed below. The size, quantity, and material from which the calibration rollers  184  are made is dependent upon and will vary as a function of the specific application. 
         [0076]    A lower radial guide carrier  176  provides a frame for the lower radial guide  180  and the molded polymer  172  to be securely seated within an associated stator segment  24 , as described below. The lower radial guide carrier  176  includes a slot  188  laterally formed therein for slidably mating with and removably accepting the radial key  178 . In order to position the molded polymer  172  within the lower radial guide  180 , the radial key  178  is seated in the lower radial calibration guide carrier  182  for guiding the stator induction module  166  in the radial direction while within the rotor channel  44 . 
         [0077]    A pair of openings  190  are provided through the radial calibration guide carrier  176 . A pair of leads  170  of the coil  168  extend through the openings  190  for connecting to a bus bar  90 ,  92 , as discussed below. 
         [0078]    As noted above, the second embodiment of the stator induction module  166  may also include an upper radial calibration guide  186  which removably mates within the slots  142  provided in the second embodiment of each rotor segment  124  ( FIG. 4 ). 
         [0079]    Both the lower radial calibration guide  180  and the upper radial calibration guide  186  are separate components from the molded polymer  172  and may be made from any suitable non-conductive, self-lubricating, polymeric material such as that sold under the trademark Teflon®, Medlen®, or the like. 
       3. Stator Segments 
       [0080]    As noted above, the stator ring  62  comprises a plurality of stator segments  64  similar to that of the rotor segments  24 . 
         [0081]    As shown in  FIG. 17 , each stator segment  64  is a substantially U-shaped frame member having a bottom wall  78 , a pair of opposed sidewalls  76  extending upwardly from the bottom wall  78 , and a pair of ledges  80  extending laterally inwardly from the opposed sidewalls  76 . The pair of ledges  80  cooperate to define a seat  82  for the stator induction modules  66  or  166  to be positioned thereupon. Throughout the ensuing description, reference will be made to the stator segment  64  being used in combination with the second embodiment of the stator induction module  166 , but it is to be understood that the first embodiment of the stator induction module  66  may similarly be seated thereon. 
         [0082]    The sidewalls  76  and the bottom wall  78  of the stator segment  64  define an interior stator channel  84 . The lower radial calibration guide carrier  182  is stationarily seated on the opposing ledges  80  within the stator channel  84 . As noted above, the stator segments  64 , through direct contact, act as a heat sink to dissipate the heat generated in the coils  168 . 
         [0083]    It should be noted that the number of stator induction modules  166  mounted in each stator segment  64  is determined by the width of the individual stator induction module  166  and the desired circumferential length of each stator segment  64  that forms the motor/generator  10  hereof. A typical stator segment  64  encompasses an array of individual stator induction modules  166 . 
         [0084]    As shown in  FIG. 18 , there is provided, at each end of the stator segments  64 , a window  86  which allows access to terminal ends  93  of a plurality of bus bars  90 ,  92 , as described below. Additionally, a plurality of fasteners  88  permit each stator segment  64  to be mechanically connected together. The fasteners  88  may also be used to mount the individual stator segments  64  to a base or floor. 
       III. Bus Bars 
       [0085]    Referring, again, to  FIG. 16 , a plurality of bus bars, including a plurality of phase bus bars  90  and at least one common bus bar  92 , is disposed within the stator channel  84 . The plurality of bus bars  90 ,  92  within each stator segment are disposed within into the stator channel  84  with their ends dammed off. They are then secured in place by surrounding and encapsulating them with a high density polyurethane foam or the like injected into the stator channel  84 . 
         [0086]    The bus bars  90 ,  92  are individually connected to their adjacent counterpart within an abutting stator segment  64  to provide a complete electrical circuit. Respective leads  170  of the coil  168  are connected to associated phase bus bars  90  and one to the common bus bar  92 . 
         [0087]    The number of phase bus bars  90  and type of electrical connection of the final assembly is optional and is determined by the way in which the individual stator induction modules  166  are connected. 
         [0088]    As shown, a single common bus bar  92  is provided for each stator induction module  166  and one additional phase bus bar  90  for each separate phase. In this arrangement, the stator induction modules  166  are electrically connected to the bus bars in a three phase “Y” configuration. 
         [0089]    It should be understood that both the stator segments  64  and bus bars  90 ,  92  remain unchanged regardless of which embodiment of the rotor segments  24 ,  124 , coils  68 ,  168 , and stator induction modules  66 ,  166  are utilized. 
       IV. Wind Turbine 
       [0090]    As noted above, the present motor/generator  10  can function as either a motor or a generator. 
         [0091]    When functioning as a motor, electricity is supplied to the motor/generator  10  which generates an electrical induction that operates on opposing poles of the magnet modules  26 . This electrical induction generates an electromagnetic field that is tangent to the rotor  20  which produces torque on the rotor  20  and causes the rotor  20  to turn. Thereafter, the rotor  20  rotates a tool or machinery operably connected thereto. 
         [0092]    As a generator, the rotor  20  rotates in the same manner as described above, thereby creating electricity via the stator induction modules  66 . Electricity is drawn through the bus bars  90 ,  92  connected to the leads  70  of the coils  68 , thus forming a completed electrical circuit. The electrical circuit ends at the plurality of terminal pins  93  of the bus bars  90 ,  92  which are provided to receive and connect to an electronic motor controller or other mechanical mechanism (not shown) to facilitate commutation and control the direction and speed of the motor/generator  10 . 
         [0093]      FIG. 19  shows the motor/generator  10  of the present invention functioning as a generator by being incorporated into a wind turbine rotor  94 . As shown, the large diameter BLPMDC generator  10  is rotatably coupled by mechanically fastening or welding it to a wind turbine rotor  94  in a direct drive application. In the example shown, a plurality of turbine rollers  96  rotatably support the wind turbine rotor  94  for rotation. The rotor  20  rotates with the wind turbine rotor  94 . The stator  60  is attached to and positioned by support brackets  98  to a turbine guide rail  99 . This establishes and dimensionally secures the relationship with the rotating rotor ring  22  and the fixed stator ring  62 . The support brackets  98  maintain the critical relationship between the rotor  20  and stator  60  while allowing the wind turbine rotor  94  to freely rotate on its axis. 
         [0094]    This arrangement reduces significantly the capital cost, maintenance, and complexity of a wind turbine system by eliminating the need for a central shaft, a gearbox, and all of the associated ancillary support components (i.e. supports, couplings, etc.). 
         [0095]    The quantity and length of each individual rotor segment  24  and stator segment  64  is determined by the overall diameter of the assembly and the maximum size that can conveniently be shipped in kit form to a remote location for subsequent assembly on site. By using segmented rotor rings  22  and stator rings  62 , a very large diameter structure can be assembled, easily transmitted to a remote job site where it will be assembled and installed in its final form. 
       V. New Assembly 
       [0096]    Referring now to  FIGS. 20-24 , and in accordance with a further embodiment, a combined rotor and stator assembly, generally, denoted at  210  comprises a circular rotor  211  and a stator  218 . The rotor  211  includes a plurality of rotor segments  213  (only one of which is shown), which, when assembled, together form the completed rotor  211 , similar to the above discussed embodiments. 
         [0097]    Here, the rotor segment  213  includes, generally, a rotor frame  214  and a plurality of magnets  212  disposed therein. 
         [0098]    As shown in  FIG. 20 , the rotor frame  214 , preferably, is formed from a lightweight metal, such as aluminum, to which the plurality of magnet  212  are attached, as described below. The rotor frame  214  comprises a two-part assembly including a rail  244  and a retainer  246 . 
         [0099]    More particularly, the rail  244  is a substantially T-shaped member having a flat plate  248  and a downwardly depending member or leg  250  integrally formed therewith and extending from a substantially medial portion of the plate  248 . The leg  250  has a lower end  252  and a slit  254  formed therein. 
         [0100]    The retainer  246 , itself, is a substantially planar plate having a plurality of longitudinal slots  258 . The slots  258  are dimensioned to stably seat an associated magnet  212 . The retainer  246  has a lower surface  260  and the upper lip  256  which projects into and seats within the slit  254  in order to position the retain  246  therein. The retainer  246  may be further secured to the plate by welding, mechanical attachments, or the like. Alternatively, the rail  244  and the retainer  246  may be integrally formed. 
         [0101]    Each magnet  212  is an elongated magnet comprising a North and South pole  222 ,  224 , respectively. In practicing this embodiment, the magnets  212  may be neodymium magnets, bonded neodymium magnets, ceramic magnets, and the like. 
         [0102]    Each magnet  212  includes a cutout section provided on at least one side of the magnet  212 . The cutout section defines a protruding shoulder  262  which abuts against a longitudinal edge of an associated slot  258 . The shoulder  262  prevents outward movement of the magnet  212  and the magnet  212  from becoming displaced from the slot  258  created by centrifugal force as the rotor  211  rotates. 
         [0103]    Each magnet  212  is disposed within an associated slot  258  of the rotor frame  214  and arrayed in alternating magnetic polarity. Additionally, the magnets  212  are further secured within each slot  258  by any suitable means such as gluing or the like. 
         [0104]    With reference to  FIGS. 23 and 24 , the stator  218  comprises a plurality of stator segments  219  (only one of which is shown), which, when assembled, form the completed stator  218 , similar to that discussed in the above embodiments. 
         [0105]    Each stator segment  219  comprises a stator frame  270 , a coil  220 , and a magnetic permeable member  216 . 
         [0106]    The stator frame  270  comprises a non-magnetic material having a bottom or base  272  and a pair of opposed upstanding sidewalls  274 ,  276  integrally formed with the base  272 . A pair of opposed shoulders  278 ,  280  are provided extending inwardly from the sidewalls  274 ,  276 , respectively. The stator frame  270  includes an open channel  286  defined by the pair of sidewalls  274 ,  276  and the interconnecting base  272 . 
         [0107]    Each magnetic permeable member  216  of the stator segment  219 , generally, comprises a substantially inverted U-shaped member  228  having a bight section  234 , and a first and a second leg  230 ,  232  extending upwardly from opposite ends of the bight section  234 . 
         [0108]    The magnetically permeable element  216  substantially envelops or circumscribes the sides and the bottom of the magnet  212 . 
         [0109]    Each magnetically permeable element  216 , preferably, is formed from a magnetic permeable material such as silicon steel and comprises a lamination stack in the same manner as described hereinabove. It is to be understood that the magnetically permeable element  216  may be partially encapsulated as at  281  with the same polymeric material as described above. 
         [0110]    The molded polymer  281  at least partially encapsulates the coils  220  and the magnetic permeable element  234 . The molded polymer  281  includes abutments  282 ,  284  which seat against the shoulders  278 ,  280 , respectively. 
         [0111]    The coil  220  is wound around the bight section  234  of the magnetically permeable element  216  and extends downwardly to ends  221 ,  223 . The ends  221 ,  223  of the coils  220  are connected to a plurality of bus bars (not shown), similar to the plurality of bus bars described in the above embodiments, and disposed within the open channel  286  of the stator frame. 
         [0112]    In use, the rotor frame  214  and associated magnets  212  are disposed in the space between the legs  230 ,  232  of the magnetically permeable element  216  and pass over the coils  220  in the same manner as described hereinabove. 
         [0113]    As shown, specifically in  FIG. 23 , this embodiment provides an assembly having dual gaps  238 ,  240  between each magnet  212  and the magnetically permeable element  216 . 
         [0114]    Here, according to the embodiment, the majority of the weight of the rotating mass of the rotor  211  is transferred to the stator  218 . 
         [0115]    Having thus described the invention, what is claimed is: 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           10  Motor/generator 
           20  Rotor 
           22  Rotor ring 
           24  Rotor segment (first embodiment) 
           26  Magnet module 
           28  Metal band 
           30  Legs 
           32  Interconnecting bight section 
           34  Magnets 
           36  Sidewalls of rotor segment (first embodiment) 
           38  Top wall of rotor segment (first embodiment) 
           44  Rotor channel 
           60  Stator 
           62  Stator ring 
           64  Stator segment 
           66  Stator induction module (first embodiment) 
           68  Coil (first embodiment) 
           69  Coil turns 
           70  Leads of coil (first embodiment) 
           72  Molded polymer (first embodiment) 
           74  Void of molded polymer (first embodiment) 
           76  Sidewalls of stator segment 
           78  Bottom wall of stator segment 
           80  Ledges of stator segment 
           82  Seat of stator segment 
           84  Stator channel 
           86  Window of stator segment 
           88  Fasteners of stator segment 
           90  Phase bus bars 
           92  Common bus bar 
           93  Terminal pins 
           94  Wind turbine rotor 
           96  Turbine rollers 
           98  Support brackets 
           99  Turbine guide rail 
           124  Rotor segment (second embodiment) 
           136  Sidewalls of rotor segment (second embodiment) 
           138  Top wall of rotor segment (second embodiment) 
           140  Protrusion of rotor segment (second embodiment) 
           142  Slot of rotor segment (second embodiment) 
           166  Stator induction module (second embodiment) 
           168  Coil (second embodiment) 
           170  Leads of coil (second embodiment) 
           172  Molded polymer (second embodiment) 
           176  Lamination stack (second embodiment) 
           178  Radial key of stator induction module (second embodiment) 
           180  Lower radial calibration guide of stator induction module (second embodiment) 
           182  Lower radial calibration guide carrier (second embodiment) 
           184  Calibration rollers of stator induction module (second embodiment) 
           186  Upper radial calibration guide of stator induction module (second embodiment) 
           188  Slot of lower radial calibration guide carrier (second embodiment) 
           190  Openings in lower radial calibration guide carrier (second embodiment) 
           210  Combined rotor and stator assembly (new embodiment) 
           211  Rotor 
           212  Magnet 
           213  Rotor segments 
           214  Rotor frame 
           216  Magnetically permeable element 
           218  Stator 
           219  Stator segments 
           220  Coil 
           221  End of coil 
           222  North pole 
           223  End of coil 
           224  South pole 
           228  U-shaped member 
           230  Leg of magnetically permeable element 
           232  Leg of magnetically permeable element 
           234  Bight section of magnetically permeable element 
           238  Dual gap 
           240  Dual gap 
           244  Rail of rotor frame 
           246  Retainer of rotor frame 
           248  Flat plate of rotor frame 
           250  Leg of rotor frame 
           252  Lower end of leg of rotor frame 
           254  Slit of rotor frame 
           256  Lip of retainer 
           258  Slot 
           260  Lower surface of plate 
           262  Shoulder of magnet 
           270  Stator frame 
           272  Base of stator frame 
           274  Sidewall of stator frame 
           276  Sidewall of stator frame 
           278  Shoulder of sidewall of stator frame 
           280  Shoulder of sidewall of stator frame 
           281  Molded polymer 
           282  Abutments of molded polymer 
           284  Abutments of molded polymer 
           286  Open channel of stator frame