Patent Publication Number: US-6707224-B1

Title: PM motor and generator with a vertical stator core assembly formed of pressure shaped processed ferromagnetic particles

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. Ser. No. 10/188,441, filed Jul. 02, 2002, now U.S. Pat. No. 6,617,747 the disclosure of which is expressly incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     Investigators in the electric motor arts have been called upon to significantly expand motor technology from its somewhat static status of many decades. Improved motor performance particularly has been called for in such technical venues as computer design and secondary motorized systems carried by vehicles, for example, in the automotive and aircraft fields. With progress in these fields, classically designed electric motors, for example, utilizing brush-based commutation, have been found to be unacceptable or, at best, marginal performers. 
     From the time of its early formation, the computer industry has employed brushless d.c. motors for its magnetic memory systems. The electric motors initially utilized for these drives were relatively expensive and incorporated a variety of refinements particularly necessitated with the introduction of rotating disc memory. For example, detent or reluctance torque phenomena has been the subject of correction. The phenomena occurs as a consequence of the nature of motors configured with steel core stator poles and associated field windings performing in conjunction with permanent magnets. With such component combinations, without correction, during an excitation state of the motor windings which create motor drive, this detent torque will be additively and subtractively superimposed upon the operational characteristics of the motor output to distort the energized torque curve, increase ripple torque, reduce the minimum torque available for starting and, possibly develop instantaneous speed variations. Such instantaneous speed variations generally have not been correctable by electronics. Particularly over the recent past, the computer industry has called for very low profile motors capable of performing in conjunction with very small disc systems and at substantially elevated speeds. 
     Petersen, in U. S. Pat. No. 4,745,345, entitled “D.C. Motor with Axially Disposed Working Flux Gap”, issued May 17, 1988, describes a PM d.c. motor of a brushless variety employing a rotor-stator pole architecture wherein the working flux gap is disposed “axially” wherein the transfer of flux is parallel with the axis of rotation of the motor. This “axial” architecture further employs the use of field windings which are simply structured, being supported from stator pole core members, which, in turn, are mounted upon a magnetically permeable base. The windings positioned over the stator pole core members advantageously may be developed upon simple bobbins insertable over the upstanding pole core members. Such axial type motors have exhibited excellent dynamic performance and efficiency and, ideally, may be designed to assume very small and desirably variable configurations. 
     Petersen in U. S. Pat. No. 4,949,000, entitled “D.C. Motor”, issued Aug. 14, 1990 describes a d.c. motor for computer applications with an axial magnetic architecture wherein the axial forces which are induced by the permanent magnet based rotor are substantially eliminated through the employment of axially polarized rotor magnets in a shear form of flux transfer relationship with the steel core components of the stator poles. The dynamic tangentially directed vector force output (torque) of the resultant motor is highly regular or smooth lending such motor designs to numerous high level technological applications such as computer disc drives which require both design flexibility, volumetric efficiency, low audible noise, and a very smooth torque output. 
     Petersen et al, in U. S. Pat. No. 4,837,474 entitled “D.C. Motor”, issued Jun. 6, 1989, describes a brushless PM d.c. motor in which the permanent magnets thereof are provided as arcuate segments which rotate about a circular locus of core component defining pole assemblies. The paired permanent magnets are magnetized in a radial polar sense and interact without back iron in radial fashion with three core components of each pole assembly which include a centrally disposed core component extending within a channel between the magnet pairs and to adjacently inwardly and outwardly disposed core components also interacting with the permanent magnet radially disposed surface. With the arrangement, localized rotor balancing is achieved and, additionally, discrete or localized magnetic circuits are developed with respect to the association of each permanent magnet pair with the pole assembly. 
     Petersen in U. S. Pat. No. 5,659,217, issued Feb. 10, 1995 and entitled “Permanent Magnet D.C. Motor Having Radially-Disposed Working Flux-Gap” describes a PM d.c. brushless motor which is producible at practical cost levels commensurate with the incorporation of the motors into products intended for the consumer marketplace. These motors exhibit a highly desirable heat dissipation characteristic and provide improved torque output in consequence of a relatively high ratio of the radius from the motor axis to its working gap with respect to the corresponding radius to the motors&#39; outer periphery. The torque performance is achieved with the design even though lower cost or, lower energy product permanent magnets may be employed with the motors. See also: Petersen, U.S. Pat. No. 5,874,796, issued Feb. 23, 1999. 
     Over the years of development of what may be referred to as the Petersen motor technology, greatly improved motor design flexibility has been realized. Designers of a broad variety of motor driven products including household implements and appliances, tools, pumps, fans and the like as well as more complex systems such as disc drives now are afforded a greatly expanded configuration flexibility utilizing the new brushless motor systems. No longer are such designers limited to the essentially “off-the-shelf” motor variety as listed in the catalogues of motor manufacturers. Now, motor designs may become components of and compliment the product itself in an expanded system design approach. 
     During the recent past, considerable interest has been manifested by motor designers in the utilization of magnetically “soft” processed ferromagnetic particles in conjunction with pressed powder technology as a substitute for the conventional laminar steel core components of motors. With this technology, the fine ferromagnetic particles, which are pressed together, are essentially mutually electrically insulated. So structured, when utilized as a motor core component, the product will exhibit very low eddy current loss which will represent a highly desirable feature, particularly as higher motor speeds and resultant core switching speeds are called for. As a further advantage, for example, in the control of cost, the pressed powder assemblies may be net shaped wherein many intermediate manufacturing steps and quality considerations are avoided. Also, tooling costs associated with this pressed powder fabrication are substantially lower as compared with the corresponding tooling required with typical laminated steel fabrication. The desirable molding approach provides a resultant magnetic particle structure that is 3-dimensional magnetically and avoids the difficulties encountered in the somewhat two-dimensional magnetic structure world of laminations. See generally U.S. Pat. No. 5,874,796 (supra). 
     The high promise of such pressed power components, however, currently is compromised by the unfortunate characteristic of the material in exhibiting relatively low permeability as contrasted at least with conventional laminar core systems. Thus the low permeability has called for 1½ to 2 times as many ampere turn deriving windings. In order to simultaneously achieve acceptable field winding resistance values, the thickness of the winding wire must be increased such that the wire gauge calls for bulksome structures which, in turn, limit design flexibility. Indeed, earlier designers confronting the permeability values available with processed ferromagnetic particle technology will, as a first inclination, return to laminar structures. This is particularly true where control over the size of the motors is mandated as, for example, in connection with the formation of brushless d.c. motors employed with very miniaturized packaging . However, the disc drive industry now seeks such compact packaging in conjunction with high rotational speeds. In the latter regard, speed increases from around 7200 rpm to 15000 rpm and greater now are contemplated for disc drives which, in turn, must perform with motors the profile of which is measured in terms of a small number of millimeters. In general, lamination-based core structures cannot perform as satisfactorily at the higher core switching speeds involved, while particulate core-based structures have been hindered by the size restraints. 
     Petersen, in application for U.S. patent application Ser. No. 09/728,236 filed Dec. 1, 2000 entitled “d.c. PM Motor With a Stator Core Assembly Formed of Pressure Shaped Processed Ferromagnetic Particles” and assigned in common herewith addresses the use of processed ferromagnetic particles to provide a d.c. PM motor of a “radial” variety wherein flux transfer at the working gap as well as core component structuring is generally aligned with radii extending from the motor axis, Efficiency is achieved, inter alia, by enhancing the coupling of the applied field into the stator core structure through the utilization of transitions in levels between the radially disposed induction region and field winding support region of each core component 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is addressed to a d.c. PM motor as well as a corresponding generator which combines a radially directed magnetic flux transference at a working or functional gap with a pole or stator core structure wherein the stator cores are in a parallel relationship with the axis of the motor. When combined with the three dimensional structuring capabilities of pressure shaped processed, mutually insulated magnetically “soft” ferromagnetic particle stator core assembly structuring, important improvements in motor performance are realized in conjunction with a capability for reduction in weight, size and cost in the latter regard, no more of the processed stator core assembly material is utilized beyond a given design tolerance factor for magnetic flux saturation. 
     A salient feature of the PM motor and generator structures hereunder resides in a broadened design flexibility accorded for essentially any given application of the technology. Motors application specific to a variety of implements, tools and appliances have been seen to replace, for example, the a.c. corded devices of the past. This replacement is with structures which are more powerful, capable of performing on battery power and yet are smaller and lighter. With respect to output torque achieved with the technology, motors configured according to the instant architecture will exhibit a ratio of radius-to-working gap (R RG ) to the radius extending to the outer periphery or surface of the motor (R M ) which is greater than about 0.6. 
     In one embodiment of the invention, the three dimensional capabilities for structuring the stator core assemblies are combined with a rotor structure having two radially outwardly disposed ring-shaped permanent magnets, each having a confronting magnetic surface adjacent oppositely disposed stator core component flux interaction surfaces to essentially double the rotor performance. By radially aligning the common polarities of the sequentially magnetized dual permanent magnets, a localized magnetic balance effect is achieved wherein the unbalance force vector evolved at one working gap is substantially cancelled by the unbalance force vector at the adjacent working gap. This feature permits a motor design wherein the internal region of the motor can be accessed from its side for a variety of purposes. For instance, the drive output of a rotor shaft may be tapped at the center of the motor to provide a side acting drive output. Such outputs can, for example, develop a linear actuator function. The attributes of the geometry and stator core materials as disclosed with respect to motor operation can equally be applied to generator operation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a chart demonstrating the variation of permeability between a conventional laminar stator core structure and a stator core structure according to the invention; 
     FIG. 2 is a perspective view of an animal hair clipper incorporating a motor structured in accordance with the invention, the figure have portions broken away to reveal internal structure; 
     FIG. 3 is a sectional view of the motor shown in FIG.  2 : 
     FIG. 4 is a sectional view taken through the plane  4 — 4  shown in FIG. 3; 
     FIG. 5 is a top view of a stator core structure employed with the motor of FIG. 3; 
     FIG. 6 is a sectional view taken through the plane  6 — 6  shown in FIG. 5; 
     FIG. 7 is a sectional view of another version of a motor structured according to the invention; 
     FIG. 8 is a top view of a stator core structure employed with the motor of FIG. 7; 
     FIG. 9 is a sectional view taken through the plane  9 — 9  shown in FIG. 8; 
     FIG. 10 is a sectional view of another version of a motor structured in accordance with the invention; 
     FIG. 11 is a top view of a stator core structure employed with the motor of FIG. 10; 
     FIG. 12 is a sectional view taken through the plane  12 — 12  shown in FIG. 11; 
     FIG. 13 is a sectional view of another motor structured in accordance with teachings of the invention; 
     FIG. 14 is a top view of a stator core structure employed with the motor of FIG. 13; 
     FIG. 15 is a sectional view taken through the plane  15 — 15  shown in FIG. 14; 
     FIG. 16 is a top view of an alternate back iron region which may be employed with the motor of FIG. 13, the view showing a core component with a bobbin as inserted within the back iron region component; 
     FIG. 17 is a sectional view taken through the plane  17 — 17  shown in FIG. 16; 
     FIG. 18 is a sectional view taken through the plane  18 — 18  shown in FIG. 17; 
     FIG. 19 is a top view of a back iron component of a stator core structure which may be utilized with the motor of FIG. 13, the figure additionally showing a section view of a core component and bobbin assembly; 
     FIG. 20 is a sectional view taken through the plane  20 — 20  shown in FIG. 19; 
     FIG. 21 is a sectional view taken through the plane  21 — 21  shown in FIG. 20; 
     FIG. 22 is a sectional view of another motor structure configured in accordance with the teachings of the invention; 
     FIG. 23 is a top view of a back iron region component utilized with the motor of FIG.  22 : 
     FIG. 24 is a front view of a stator core component employed with the motor of FIG.  22  and the back iron component shown in FIG. 23; 
     FIG. 25 is a bottom view of the stator core component shown in FIG. 24; 
     FIG. 26 is a top view of a fan and motor assembly configured in accordance with the teachings of the invention with a top portion removed to reveal internal structure; 
     FIG. 27 is a sectional view taken through the plane  27 — 27  shown in FIG. 26 which further incorporates portions removed from FIG. 26; 
     FIG. 28 is a top view of a back iron region component employed with the assemblage of FIG. 26; 
     FIG. 29 is a perspective view of a stator core component employed with the assemblage of FIG. 26; 
     FIG. 30 is a sectional view of a motor with the architecture of the invention associated with drill related components including a reduction gear train; 
     FIG. 31 is a sectional view of a generator structured according to the invention; 
     FIG. 32 is a top view of a stator core structure employed with the generator of FIG. 31; 
     FIG. 33 is a sectional view taken through the plane  33 — 33  shown in FIG. 32; 
     FIG. 34 is a schematic electrical diagram of field windings and a rectifier for a single phase adaptation of the generator of FIG. 31; and 
     FIG. 35 is an electrical schematic diagram of the field windings and rectifier networks for a three-phase adaptation of the generator of FIG.  31 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the discourse to follow, a salient characteristic of the motors described, resides in the presence of a flux gap wherein magnetic flux interaction is generally in a radial direction, i.e., along a radius from the motor axis and wherein the core components of the stator assembly generally are arranged in a fashion in parallel with the axis of the motor. Thus, electromagnetic flux induced from the field windings travels in general along a path which may be considered parallel with the motor axis, while magnetic flux interaction at the working or functional gap of the motor is, as noted above, considered as a radial transference. A variety of advantages accrue from this arrangement, particularly with the three dimensional attributes available with a stator core assembly formed with pressed powder metal technology. In this regard, requisite cross sections of the core material are readily available to avoid saturation at designed maximum load and the number of turns in the field winding region can be varied to meet the specific needs of an application independently of the extent of the permanent magnet induction area. Accordingly, the motors which evolve from the instant technology are referred to as application specific. In general, for a given application, the motors will provide improved output at lower weight, size and cost. The latter cost aspect is minimized through the above-discussed fabrication techniques available with these materials and by virtue of the designer being given the opportunity to design specifically to the maximum load characteristics anticipated with a given motor application. No more stator core material need be utilized than is necessary to provide, for example, a design safety factor for saturation of about 20% to 25%. 
     FIG. 1 illustrates the immediately apparent design disadvantage occasioned by the low permeability design parameter accompanying utilization of processed ferromagnetic materials for core structuring as compared with a quality lamination material. In the figure, curves are shown which plot permeability with respect to induction in kilogauss (kG). Curve  10  is developed from a conventionally available laminate material identified as M-19FP having a 24 gauge thickness. The reader may now contrast the permeability characteristics of this conventional material with the corresponding permeability characteristics of the processed ferromagnetic materials as are employed with the motors of the invention, as represented at curve  12 . The material deriving in curve  12  is identified as SM-2HB marketed by Mii Technologies, LLC of West Lebanon, N.H. This material is described as having low eddy current losses as a percentage of hysteresis loss. For example, at 60 Hz, and an induction of 1.5 Tesla, the material exhibits 9% eddy current loss and 91% hysteresis loss. The material is capable of providing a significant advantage for electrically commutated motors that operate at frequencies higher than line frequencies. However, its permeability characteristics would, at first observation, render it unfit to meet the packaging and performance criteria sought in many applications. In fact, for the motor designs at hand, the low permeability characteristics readily are accommodated for while the motors are ideally suited for application specific utilization. 
     Such an application specific employment of the instant technology is represented in FIG.  2 . In the figure, a hand-held hair clipper is represented generally at  14 . The clipper  14 , while incorporating conventional reciprocal driven blades or cutters represented generally at  16 , employs a d.c. PM motor according to the invention as represented in general at  18  located within a hand-held plastic housing represented in general at  20 . Power to the motor  18  is provided from a battery pack formed as an extension of housing  20  as represented in general at  22  and the device  14  may be activated or actuated by a switch button assembly represented in general at  24 . Device  14  replaces an a.c. corded brush-type motor dipper with a structure having more power and lighter weight even with the addition of the weight of battery pack  22 . Motor  18  is fixed within the interior of housing  20  at a grooved circular aluminum base represented generally at  26  through which the motor shaft  28  (seen in FIG. 3) extends for connection with the noted blade drive eccentric mechanism. Extending about the periphery of the base  26  is an integrally formed powdered metal stator core structure having six poles or core components extending from an integrally formed back iron region in generally parallel relationship with the axis of motor  18 . Portions of the back iron region are shown at  30  and field winding assemblies associated with the winding regions of the core components are represented generally at  32 . Seen extending upwardly for each core component are portions of bobbin assemblies certain of which are represented in general at  34 . Each of these bobbins within the assembly  34  supports beginning and ending leads from the field windings in slots formed therein. Certain of these leads are shown at  36  as they are so supported and extended to slots formed within a printed circuit board  38 . At printed circuit board  38  the leads are interconnected to provide for three phase operation of motor  18 . These leads also function to retain the printed circuit board  38  in place. 
     Referring to FIG. 3, motor  18  reappears in conjunction with aluminum base  26 . Base  26  is configured symmetrically about the axis  50  of motor  18 , having a forward flange represented in general at  52  the circular edge  54  of which carries a connecting groove  56  which is engageable with support structures internally of the device housing  20 . Supported upon the annular rearward surface  60  of flange  52  as well as in conjunction with a recessed cylindrical base shoulder portion  62  is a pressed powder metal stator core assembly  64 . 
     Looking momentarily to FIGS. 5 and 6, the integrally formed stator core assembly  64  is seen to incorporate spaced apart isotropic core components  66   a - 66   f . As represented in FIG. 6, each such core component  66   a - 66   f , in turn, includes a flux interaction region  68   a - 68   f  which has length along the motor axis which is generally coextensive with the principal dimension of the permanent magnet assembly of an associated rotor. The flux interaction regions  68   a - 68   f  are each integrally associated with a winding region as represented in general at  70   a - 70   f , winding regions  70   a ,  70   d  and  70   e  being seen in FIG.  6 . These winding regions also are arranged generally in parallel with the motor axis  50  and extend a field winding length from a location in spaced adjacency with the flux interaction region to an integrally formed annulus shaped back iron region  30 . Note that the radial dimension of back iron region  30  is enlarged by being stepped outwardly as at  74 . This enlarged resultant magnetic flux confronting cross sectional area is designed to avoid saturation with a safety factor of, for instance, about 20% to about 25%. FIG. 6 further reveals an upstanding cylindrically shaped cavity  76  which functions to receive a locating pin. 
     The internal surface  78  of the back iron region  30  is slide fitted and glued against base shoulder portion  62  as represented in FIG.  3 . Returning to that figure, formed within the base shoulder portion  62  are two annular adhesive-retaining grooves  80  and  82  to secure the assembly  64 . 
     Base  26  further is configured to define an open cylindrical bearing housing  84  which is symmetrically disposed about motor axis  50  and functions to rotatably support motor shaft  28  with structurally robust ball bearings  86  and  88 . In this regard, the inner races of bearings  86  and  88  support and rotate with the shaft  28  and, bearing  86  is spaced apart from bearing  88  with a spacer cylinder  90  which is glued into position. Shaft  28  is retained in position by a snap ring  92  located within a shaft groove  94  and a spring or wavy washer  96  abutting the outside surface of bearing  86 . The outside surfaces of bearing  86  and  88  are glued in position. 
     Attached to the shaft  28  is a permanent magnet carrying rotor represented generally at  100  and formed having a cylindrical steel back iron  102  with a cylindrical outer surface  104  which carries a four segment or region cylindrical permanent magnet  106 . Permanent magnet  106  preferably is formed from a bonded rare earth material and provides a confronting magnetic surface  108  which is spaced from the corresponding flux interaction regions as shown in FIG. 3 at  68   a  and  68   d  a working or functional gap distance to define the working gap  110 . The confronting magnetic surface  108  is configured with a principal dimension parallel with the motor axis  50  which corresponds or is generally coextensive with the length in parallel with motor axis  50  of the flux interaction regions  68   a - 68   f.    
     FIG. 3 reveals that the winding regions  70   a - 70   f  (regions  70   a  and  70   d  being shown In the figure) extend a field winding length from a location at the inward winding flanges  112   a - 112   f  of the individual bobbins  114   a - 114   f  of the bobbin assembly  34  to the integrally formed back iron region  30 . Accordingly, the winding regions extend in generally parallel relationship with the motor axis  50  that field winding length from a location in spaced adjacency with the flux interaction regions  68   a - 68   f . This provides for clearance of the windings and the winding flanges  112   a - 112   f  from the lower surface of the rotor  100 . 
     Looking additionally to FIG. 4, the individual bobbins as represented at  114   a - 114   f  are revealed. As indicated in connection with the description accompanying FIG. 2, bobbins  114   a - 114   f  are each configured additionally with an integrally formed elongate lead support portion  116   a - 116   f . Those lead support portions incorporate slots as shown at  118   a - 118   f  which in turn support the beginning and ending leads of the windings, two of which are seen in FIG. 3 at  120   a  and  120   d . Leads  36  are joined at the circular printed circuit board  38  to define the excitation circuit. As part of the excitation control, for a typical three phase implementation, three Hall effect devices are employed, one of which is seen in FIG. 3 at  122  located over the working gap  118  at the underside of circuit board  38 . The figure also reveals a positioning pin  124  within the cavity  76  and a threaded attachment bore  126 . 
     A characteristic of the instant motor designs resides in the rather substantial amount of space available internally within the motors. For the embodiment of the instant figures, that space is taken by quite robust ball bearings which are used in view of the side loads imposed upon shaft  28  by the eccentric drives of the clipper apparatus  14 . Substantial torque is achieved with the motor  18  by virtue, inter alia, of the ratio of the radius, R M  (38/2 mm) from motor axis  50  to the outside surface of the motor with respect to the radius to the gap, R G  (27/2 mm). The latter radius is measured from the motor axis  50  to the internally disposed surface of the core component flux interaction regions  68   a - 68   f . For the instant application, that ratio amounts to about 0.71, a quite high value for the size of the motor employed. In general, this ratio will equal or exceed about 0.6 for the “vertical” core component and radial flux interaction structuring. Note that the motor  18  provides no moving components at its outside surface other than the protruding shaft  28 . As a consequence, the outside of the motor is available for mechanical purposes, including the mounting of it within housing  20 . 
     Referring to FIGS. 7-9, a larger motor structure applying the instant architecture is revealed in general at  130 . Motor  130  is configured with a generally cylindrically shaped motor base  132  formed of aluminum. Within the base  132  there is machined an annular groove represented generally at  134  exhibiting a rectangular cross section. Of this cross section, the outer annular surface  136  functions as a control for the press fitting insertion thereinto of a stator core assembly represented generally at  138 . Assembly  138  is formed of pressure shaped processed ferromagnetic particles which form, in conjunction with a ring-shaped base, nine isotropic upstanding core components shown in FIG. 8 at  149   a - 140   i . As before, each of the core components  140   a - 140   i  of the stator core assembly  138  is generally arranged in parallel relationship with the motor axis. Returning to FIG. 7, that axis is revealed at  142  extending through the center of the motor shaft  144 . Shaft  144 . In turn, is mounted within a bearing housing represented generally at  146 . Housing  146  is formed within the aluminum base  132  as a cylindrical portion  148  having shoulder defining countersunk regions for supporting two ball bearing structures  150  and  152 . In this regard, bearing  150  is located against an annular shoulder  154 , while bearing  152  nests against a similar annular shoulder  156 . Shaft  144  extends through a washer  158  for engagement with a rotor represented generally at  160 . Rotor  160  incorporates a nonmagnetic rotor support portion  162  which may be formed with a high strength plastic. Portion  162  is generally cylindrically shaped and fixed to shaft  144  and its outer cylindrical surface  164  is fastened to a ring-shaped back iron component  166 , the outward surface of which, in turn, supports a bonded rare earth magnet ring  168 . Looking additionally to FIGS. 8 and 9, as before, each of the core components of the stator core assembly, while arranged in generally parallel relationship to motor axis  142 , is formed with a flux interaction surface represented generally at  170   a - 170   i . As seen at flux interaction surfaces  170   a  and  170   f  in FIG. 7, those surfaces are located in spaced adjacently with and coextensive with the adjacent rotor confronting magnetic surfaces shown at  172  to define a working or functioning gap represented at  174 . Integrally formed with and extending from the flux interaction surfaces  170   a - 170   i  are the winding regions  176   a - 176   i  which extend, in turn, a field winding length from spaced adjacency with the flux interaction surfaces as described at  170   a - 170   i  to a ring-shaped back iron region  178 . As described earlier, the entire stator core assembly  138  is integrally formed using the noted pressure shaped processed ferromagnetic particles. Note that the external surface of the back iron region  178  is located in controlled surface adjacency with the groove surface  136  of groove  134  for fabrication control purposes. FIG. 7 shows one of the nine polymeric bobbins as at  180  which is configured in conjunction with field windings as at  182 . This structuring is repeated for each of the core components  140   a - 140   i . Base  132  further is configured with an outer shoulder portion  184  which receives a corresponding flange of a cylindrical aluminum or polymeric motor side component  186 . Component  186 , in turn, extends to connection with a polymeric top and circuit support  188  having a circular opening  190  formed centrally therewithin and supporting connector assemblages as at  192  and  194  as well as three Hall effect sensing devices for a conventional three phase control, one of such Hall devices being represented at  196  on the underside of the circuit support  188  over working gap  174 . 
     In general, the rotor magnet ring  166  will be provided with six regions or magnetic segments of alternating polarity. The motor  130  generally performs at a rotational speed of about 6000 rpm and may function, for example, as a an automotive fuel pump. For this application, a pump impeller may be integrated with the rotor structure with alterations to the bearing structure. Such an arrangement is made available by the relatively large amount of open volume at the center region of these motors. Finally, FIGS. 7 and 9 reveal a positioning pin cavity  196  formed within the back iron region  176 . The motor  130  will exhibit the above-noted working gap to outside surface radii ratio, R G/R   M  of greater than about 0.6. 
     Referring to FIGS. 10-12, a motor represented generally at  210  is illustrated. Motor  210  is of relatively flat architectural demeanor having a stator core assembly  212  with eighteen isotropic core components performing in conjunction with a rotor represented generally at  214  which is configured having sequence of twelve or sixteen magnetic regions or segments of alternating polarity. Motor  210  functions to drive an automotive blower fan and its rotational speed is in a range of about one thousand to five thousand rpm. The motor is formed incorporating an aluminum base  216  having an annular groove  218  machined therein exhibiting a rectangular cross section with an outwardly disposed control surface  220 . Stator core assembly  212  as revealed in connection with FIGS. 11-12 is formed having upstanding core components  222   a - 222   r . Unlike the earlier embodiments, the flux interaction surfaces  224   a - 224   r  face radially outwardly from the motor axis  226  (FIG.  10 ). Flux interaction surfaces  224   a - 224   r , as before, are located adjacent the confronting magnetic surface of the rotor  214 . In this regard, FIG. 10 shows the rotor  214  to be mounted for rotation about axis  226  upon a motor shaft  228 . Shaft  228 , in turn, is supported from a base-mounted bail bearing located within a cylindrical cavity  232  formed in base  216 . Cavity  232  is formed with a shaft access opening  234  through which shaft  228  passes into engagement with rotor  214  at a flange plate assembly  236 . Plate assembly  236  is attached by machine screws, one of which is revealed at  238  to a rotor body  240 . Shaft  228  extends through an opening  242  in cylindrical motor housing  244  to be engaged with housing mounted ball bearing  246 . The shaft is secured within this bearing mounting arrangement by a snap ring  248  positioned within a groove  250  within shaft  228  adjacent bearing  230  and with a washer  252  and snap-on spring washer arrangement  254  engaged within a groove  256  formed within shaft  228  adjacent bearing  246 . 
     Rotor body  240  extends to a ring-shaped back iron  258  the radially inwardly lower surface of which supports a ring-shaped bonded rare earth magnet  260 . Note that rotor body  240  is fabricated out of a nonmagnetic and preferably non-conductive material because of its close proximity to the top of the stator core components  222   a - 222   r  which are transient flux carrying elements. It is not desirable to induce a field or current into the rotor body. Magnet  260  has an inwardly radially directed confronting magnetic surface  262  which is coextensive with and adjacent to the flux interaction surfaces  224   a - 224   r  to define a working or functional gap  264  providing for a generally radially evoked interaction of magnetic flux. Housing  244  is of generally cylindrical configuration, having an outwardly disposed annular flange portion  266  which attached to the inward surface of base  216  by a plurality of machine screws, two of which are shown at  268 . 
     As revealed in FIGS. 10 and 12, isotropic core components  222   a - 222   r  extend from the noted flux interaction surfaces  224   a - 224   r  to integrally formed winding regions  270   a - 270   r . Regions  270   a - 270   r  have a general parallel relationship with the motor axis  226  and extend a field winding length from a location in spaced adjacency with the flux interaction surfaces  224   a - 224   r  to a ring-shaped back iron region  272 . Note that region  272  has an expanded radial dimension of cross sectional area selected in correspondence with the noted saturation design criteria. Extending over each of the core components  222   a - 222   r  are polymeric bobbins, two of which are seen in FIG. 10 at  274   a  and  274   j , each of these bobbins being associated with each core component field winding region and carrying field windings, two of which are shown at  276   a  and  276   j.    
     No rotor  214  rotational detectors such as Hall devices are shown in the FIG.  10 . For this larger motor a circuit arrangement to detect rotor position is utilized incorporating a back EMF type motor controller manufactured by Fairchild Semiconductor Corp. of South Portland Me. 04107. As is apparent from FIG. 10, the gap radius/motor radius ratio, R G /R M , for this radially outwardly gapped structuring is quite high contributing to improved torque performance. 
     Referring to FIGS. 13-15 a motor having an architecture evoking higher power levels as well as enhanced application is shown in general at  290 . Motor  290  is configured having a stator core assembly represented generally at  292  which incorporates eighteen core components or poles and performs in conjunction with a rotor magnet exhibiting twelve zones or segments of alternating magnetic polarity. However, those twelve zones are provided in each of two radially spaced apart bonded rare earth ring magnets working with two radially spaced apart working or functional gaps developed in conjunction with oppositely disposed flux interaction surfaces. 
     Looking to FIG. 13, the motor  290  is seen to be formed with a base  294  formed of aluminum so as to accommodate for heat buildup. The base  294  is configured to integrally incorporate a cylindrically shaped bearing housing  296  having a downwardly disposed cylindrical opening  298  into which the lower portion of a motor shaft  300  extends for free rotation. Shaft  300  is supported within the bearing housing  296  by upper and lower ball bearings shown respectively at  302  and  304  which are spaced apart by an aluminum cylindrical bearing spacer  306 . Above the bearing  302 , shaft  300  is attached to a rotor shown generally at  308 . Rotor  308  is formed having a rotor body  310  formed of a rigid plastic material such as a glass reinforced modified polyethylene terephthalate (PET) sold under the trade designation Rynite 545NCCC010 by DuPont de Nemours Co, Inc. Note that rotor body  310  is formed of a nonmagnetic and non-conductive material for the same reasons as was rotor body  240  of motor  210  shown in FIG.  10 . The rotor body  310  extends initially to a peripherally disposed ring-shaped outer back iron  312  which radially inwardly is connected to a bonded rare earth ring-shaped permanent magnet  314  having a confronting magnetic surface  316  facing radially inwardly. Spaced radially inwardly from the back iron ring  312  is a second back iron component having a generally ring-shaped and L-shaped cross sectional configuration as represented at  318 . Attached radially outwardly of the back iron  318  is an inwardly disposed ring-shaped permanent magnet  320 . Magnet  320  has a radially outwardly facing confronting magnetic surface  322 . Each of the permanent magnets  314  and  320  are formed with twelve magnetic segments or regions which alternate in polarity and, for the instant embodiment, those polarities for each magnet  314  and  320  are in polar alignment for the purpose of maximum torque generation and locally eliminating unbalance force vectors that would otherwise exist at each energized pole-magnet air gap. 
     Magnet rings  314  and  320  perform in concert with stator core assembly  292  which, as before, is formed of pressure-shaped processed ferromagnetic particles and is integrally formed generally in the shape of an inverted “T”. The eighteen spaced apart isotropic core components of the core assembly  292  are seen in FIGS. 14 and 15 at  324   a - 324   r . Each of these core components  324   a - 324   r  are configured with oppositely disposed flux interaction surfaces which are generally coextensive with the principal dimensions taken in parallel with motor axis  326  of the permanent magnet confronting surfaces  316  and  322 . FIG. 14 shows the radially inwardly disposed flux interaction surfaces at  328   a - 328   r  which establish the radially inwardly disposed working or functional gap  330  as seen in FIG.  13 . The radially outwardly disposed flux interaction surfaces of core components  324   a - 324   r  are shown respectively at  332   a - 332   r . These outwardly disposed flux interaction surfaces  332   a - 332   r  perform in concert with confronting magnetic surface  316  to establish a radially outwardly disposed working or functional gap seen in FIG. 13 at  334 . The cross-sections of the core components  324   a - 324   r  as particularly seen in FIGS. 13 and 15 reveal that their uppermost tips are configured to more efficiently assign flux interaction to the oppositely disposed flux interaction surfaces  328   a - 328   r  and  332   a - 332   r . This is carried out by forming a somewhat shallow valley within the top of each core component These valleys, as seen at  336   a - 336   r , in effect, force magnetic flux to the oppositely disposed flux interaction surfaces. Valleys  336   a - 336   r  are readily formed utilizing the pressing manufacturing approach for the stator core assembly  292 . 
     As in the earlier embodiments, the core components  324   a - 324   r  integrally incorporate winding regions as shown at  338   a  and  338   j  in FIGS. 13 and 15. These winding regions reside in spaced adjacency with the flux interaction surfaces  328   a - 328   r  and  332   a - 332   r  and extend a field winding length to an integrally formed ring-shaped back iron region  340 . Back iron region  340  is press fitted into an annular groove  342  formed within the base  294  as seen in FIG.  13 . FIG. 13 also reveals two of the eighteen bobbins employed to carry the field windings for each core component. In this regard, a bobbin  344   a  is shown carrying a field winding  346   a  and a bobbin  344   j  is seen supporting field winding  346   j.    
     FIG. 13 also illustrates that the somewhat large internal volume of the motor  290  is utilized for mounting a control electronic circuit board  348  which is mounted upon a ring-shaped aluminum stand off  350  fixed by machine screws as at  352  to the base  294 . Aluminum stand-off  350  serves to form a heat sink in combination with aluminum base  294 . Circuit board  348  carries the requisite number of Hall effect devices utilized for, for example, three phase control. One such Hall effect device is shown at  354  performing in conjunction with a slave magnetic ring  356  supported from back iron  318 . Slave magnet  356  is magnetized with regions corresponding with the magnetization of ring magnets  314  and  320 . Motor  290  further is configured having a housing formed of the earlier described rigid plastic material and shown at  358 . Housing  358  is secured to the base  294  by machine screws, certain of which are revealed at  360 . 
     An important feature associated with the utilization of two radially spaced rotor magnets as at  314  and  320  resides in a localized negation of motor unbalancing force vectors which occur in almost all motor working gaps. It may be recalled that the magnetic segments or regions are radially aligned facing north-to-north and south-to-south. As the magnets move from a condition of being equal field centered (half N-S) over each individual energized stator pole the unbalance force vectors at that pole commence to be created. However, those vectors are substantially equal and directly oppositely disposed at each oppositely disposed pole gap, in effect, mutually canceling. This localized elimination of unbalance force vectors serves to amplify the scope of applications to which motor  290  may be employed. For example, the motor shaft can be accessed from the side by the elimination of core components. A typical three phase control will repeat, for example, in a phase A-phase B-phase C-phase sequence and those core components involved in that sequencing generally are juxtaposed to each other. Thus, for example, three core components can be removed and the motor will still operate satisfactorily. However it will perform with fifteen instead of eighteen core components or poles and thus will exhibit fifteen eighteenths of its otherwise available torque. The side entry opening may, for example, access the motor shaft to provide a crank and eccentric output extending from the side of the motor or, for example, a pulley may be internally disposed with the shaft to carry a belt output extending from the side of the motor. 
     For some applications, it is desirable to circumferentially flair the flux interaction surfaces of the core components. Referring to FIGS. 16-18, the structuring of the stator core assembly having core components with such flared flux interaction surfaces is revealed. An advantageous aspect of the pressure shaped processed ferromagnetic particle construction resides in the attribute that this material can be pressed as separate components which then are abutted together and adhesively interconnected. These interconnections preferably are held in a compressive state as opposed to a tensional state. In order to provide flared flux interaction surfaces, it is necessary that the bobbins and associated field windings be inserted from the back iron region of the stator core assembly. FIG. 16 reveals a discrete ring-shaped back iron component  370  having a circular outer circumference  372  and an inner circumference as at  374  which is interrupted by a sequence of eighteen key slots  376   a - 376   r  located at the core component or pole positions. One core component having a flared tip is shown in FIG. 17 in general at  378 . The structure of this core component  378  is duplicated for each of the core component positions and, as seen in FIGS. 17 and 18, the oppositely disposed flux interaction surfaces are identified at  380  and  381 . FIG. 18 reveals that these surfaces  380  and  381  are flared or extended circumferentially. Immediately below these flux interaction surfaces  380  and  381  there is integrally formed the field winding region  384  which in turn extends to a component of the back iron region at  386 . Before the back iron region component  386  is inserted within a slot as at  376   j , a bobbin and field winding assembly, as represented respectively at  388  and  390 , is inserted over the back iron region component  386  and into position against the field winding region  384 . The sub assembly then is inserted and adhesively attached to slot  376   j  as seen in FIG.  17 . As in the case of motor  290 , the tip of each core component is formed with a flux directing valley as seen at  392  in FIGS. 16 and 17. 
     Upon initial assembly of the stator core component as at  370  with associated bobbins and field windings, that assembly then is located within a slot or annular groove as earlier described at  342  in connection with FIG.  13 . To provide for compressive engagement of the back iron region components  386  with the remainder of the back iron component as at  370 , the radial thickness of the back iron region component  386  as well as the remaining components of the core component are arranged so that the radially inwardly exposed surface of back iron components as at  386  protrude slightly inwardly from the inner circumference surfaces  374 . Following installation in a groove as at  342  as described in connection with FIG. 13, a compression ring preferably formed of steel is inserted to press against these exposed core component surfaces to urge the individual core components into a compressive engagement with the component  370 . 
     In an alternate assembly embodiment, one skilled in the art can readily see that the back iron component  370  can be formed with outwardly facing key slots where the assembly compressive ring is applied to the outer exposed surfaces of the slightly protruding back iron regions of the stator core components as shown in FIG.  23 . 
     Referring to FIGS. 19-21, another approach to providing a stator core assembly wherein the core components have circumferentially flared flux interaction surfaces is revealed. In the figure, a ring-shaped back iron formed of the pressure shaped pressed ferromagnetic particle is represented in general at  400 . Back iron  400  includes outer and inner circumferential edges shown respectively at  402  and  404 . The back iron  400  is pressed such that an upstanding standard or post extending, for example, a field winding length is provided. These standards or posts are shown in FIGS. 19 and 20 at  406   a - 406   r . Standards  406   a - 406   r  form one half of the field winding region of each isotropic stator core component as revealed in FIG.  20 . In this regard, as seen additionally in FIG. 21, each core component is discretely pressed with oppositely disposed flux interaction surfaces as shown at  408  and  409  which are spaced apart a common width. A combined resulting field winding region is shown in FIG. 20 at  410 . That field winding region represented at  410  is formed, for example, of standard  406   j  and an extension  412  each representing half the width of the region  410 . The pressed components are joined together at a joint representing a lap joint as indicated by the joint outline represented generally at  414 . While these two components may be adhesively attached together, they are retained together by a polymeric bobbin as at  416  carrying field windings as at  418 . 
     One of the characteristics of the motors at hand is a tendency of the permanent magnet to be biased axially downwardly along the core components. This may be referred to as a tendency of the permanent magnet to satisfy itself resulting in a downward axial magnetic force vector. This axial vector is substantially eliminated with the stator core assembly illustrated in connection with FIGS. 22 through 25. Looking to FIG. 22, a motor is represented generally at  430  having an aluminum base  432  incorporating a bearing housing portion  434  of cylindrical shape disposed symmetrically about the motor axis  436 . Bearing housing  434  supports spaced apart upper ball bearing  436  and lower ball bearing  438 . The latter bearing is seen to be positioned against an annular ledge  440  formed within the bearing housing portion  434 , while the upper bearing  436  is supported by an aluminum cylindrical bearing spacer  442 . Bearings  436  and  438  support motor shaft  444  which is fixed to a rotor shown generally at  446 . In this regard, connection between the shaft  444  and the rotor  446  is made at a cup-shaped rotor body component  448 . Body component  448  may be formed of the earlier-described glass reinforced modified polyethylene terephthalate (PET). The shaft  444  with rotor  446  is inserted through bearings  436  and  438  and secured adjacent ball bearing  438  with a spring or wavy washer  450  in combination with a retaining ring  452  located within a shaft groove  454 . Rotor body component  448  supports a steel, cup-shaped back iron  456  which, in turn, supports a ring-shaped bonded rare earth permanent magnet  458 . The confronting magnetic surface of magnet  458  at  460  is seen to have a principal dimension in parallel with motor axis  436  which permits it to slightly overlap the flux interaction surfaces of the stator core assembly represented generally at  462 . FIG. 22 reveals two of the six core components as shown in general at  464   a  and  464   d . Formed of the isotropic pressure shaped processed ferromagnetic particles, the core components of stator core assembly  462  incorporate a flux interaction surface which extends radially inwardly from the field winding region. Note in this regard, the flux interaction surface  466   a  of core component  464   a  and the corresponding flux interaction surface  466   d  of core component  464   d . The core component regions immediately associated with these flux interaction surfaces are seen to be thicker than the field winding regions shown at  468   a  in conjunction with core component  464   a  and at  468   d  in conjunction with core component  464   d . Because of the extended thickness of the core component region adjacent the flux interaction surfaces, the bobbin and field winding assemblies are inserted from the back iron region which is formed as two compressibly and adhesively joined parts. In this regard, the back iron region of core component  464   a  includes integrally formed back Iron region  470   a  which is compressibly joined with a back iron base member  472 . Similarly, the integrally formed back iron region of core component  464   d  is shown at  470   d  in association with back iron base member  472 . 
     Referring to FIG. 23, the back iron base member  472  is shown to have a general ring-shape extending between outer circumferential edge  474  and inner circumferential edge  476 . Outer circumferential edge  474  is discontinuous, being formed with “T” slots  478   a - 478   f . Looking additionally to FIG. 24, the core component  464   a  is illustrated in a manner looking radially outwardly from the motor axis  436 . In the figure, the inwardly offset flux interaction surface  466   a  appears which is integrally formed with field winding region  468   a  and the key component of the back iron region  470   a . A bottom view of component  464   a  is seen in FIG.  25 . The back iron key component  470   a  is, for example, inserted in the slot  478   a  of back iron base member  472  and this arrangement reoccurs for each of the six poles or core components. However, before that insertion occurs, a polymeric bobbin associated with each core component, usually having been wound with a field winding is inserted over the field winding region from the back iron key region, for example, as at  470   a . Returning to FIG. 22, a bobbin  480   a  is seen supporting field winding  482   a  at the field winding region  468   a . Correspondingly, the bobbin  480   d  carrying field winding  482   d  is shown positioned over winding region  468   d  of core component  464   d . The assemblage of the core components as at  464   a  and  464   d  and the base back iron component  472  is retained in compression by a steel compression ring seen in FIG. 22 at  484 . With the arrangement, working or functional gaps as seen at FIG. 22 at  486   a  and  486   d  are established. The upper assembly also is structurally supported by an upper support or ring member  488 . That member  488  further carries a C-shaped circuit support  490  which is attached thereto by machine screws one of which is shown at  492 . In general, the support  490  functions to position three Hall effect devices over the gap as at  486   d , one such Hall device being shown at  494 . 
     With the structuring shown, the noted axial bias of the permanent magnet  458  occasioned by Its otherwise proximity to the stator winds essentially is eliminated to permit, for example, quieter operation. An aspect of the particular structure shown is an essential absence of manually discemable detent torque. The motor as described in FIGS. 22 to  25  can be reconfigured such that the radially extending flux interaction surfaces of the core components extend radially outwardly from the winding region and the motor incorporates a rotor configured as in FIG. 10 with an inwardly facing confronting magnetic surface. This configuration would yield similar results but with an improvement in the Rg/Rm ratio. 
     The architecture of the instant motors as characterized by the radially directed flux transfer at the working gap combined with a “vertical” pole or core component assemblage permits the structuring of the motors such that they may comprise only a small portion of a given rotational application. This is demonstrated by the motorized fan illustrated in connection with FIGS. 26 through 29. Looking to FIGS. 26 and 27, the fan as represented generally at  500 , is seen to incorporate a motor rotor represented generally at  502  which is configured with a steel ring-shaped back iron  504  which is coupled, in turn, with a bonded rare earth ring-shaped permanent magnet  506 . Rotor  502  is rotationally mounted upon a plastic base  508  having integrally formed upstanding sidewall  510 . Supported by plastic web components (not shown) is a cylindrical aluminum bearing housing  512  which is disposed symmetrically about motor axis  514 . The cylindrical housing  512  is supported from a plastic collar  516  which is supported, in turn, by the noted web components (not shown) which extend from the base  508 . Cylindrical housing  512  supports an upwardly disposed ball bearing  518  and a lower disposed sintered bronze bushing  520 . Bearings  518  and  520 , in turn, support steel motor shaft  522  which is fixed to rotor  502  at a lower blade support  524 . Support  524  is formed of plastic and includes fan blade elements  528  which extend from surface  574  and mate with surface  576  of upper blade support  526  which additionally supports the back iron ring  504  and permanent magnet  506  forming the entire rotor  502 . The fan blades shown generally at  528  in FIG. 26 exist between surface  574  and  576  and perform in conjunction with an air intake opening represented generally at  530  which is surrounded by a plastic top member  532  as seen in FIG.  27 . The opening in top member  532  is seen at  534  in the latter figure. 
     Shaft  522  is mounted with a washer  536  located above ball bearing  518  and is retained by an E-ring  538  configured about a groove  540 . The stator core assembly and associated bobbins and field windings of the two pole motive function are represented in general at  542  and includes stator core components  544   a  and  544   b  which are formed of the noted pressure formed or shaped processed ferromagnetic particles to provide an upper region establishing flux interaction surfaces shown respectively at  546   a  and  546   b . Surfaces  546   a  and  546   b  are located in spaced adjacency with the confronting magnetic surface  548  of permanent magnet  506  to develop working or functional gaps as at  550   a  with respect to flux interaction surface  546   a  and  550   b  with respect to flux interaction surface  546   b . Extending below the flux interactive surfaces are integrally formed field winding regions as exemplified at  552   a  as represented in FIGS. 27 and 29. Such regions extend a field winding length from adjacency with the flux interaction surfaces to a back iron region component shown at  554   a  in FIGS. 27 and 29. Those back iron region components are configured to be inserted within an arcuate back iron base component represented in general at  556  Component  556  is shown in FIG. 28 as incorporating arcuate slots  558   a  and  558   b  for receiving the back iron region components as described at  554   a . Prior to the insertion into slots  558   a  and  558   b , bobbin and field winding assemblies are positioned over the field winding regions as at  552   a . In this regard, a polymeric bobbin  560   a  is shown associated with core component  544   a  and a polymeric bobbin  560   b  is shown associated with stator core component  544   b . FIG. 27 reveals a field winding  562   a  supported by bobbin  560   a . The motor function of fan  500  is of a two phase variety and it is necessary for star-up purposes that the mechanical detent or rest position be spaced from the energized zero torque position. This feature is developed by providing a cut off corner at the region of the flux interaction face as at  546   a  as shown in connection with FIG. 29 at  564   a , as well as providing an extension of the flux interaction surface  546   a  as shown at  566   a . When the fan is energized, air enters as represented at arrow  568  near the center of the fan in FIG.  27  and exits around the bottom edge, as represented at corresponding arrows  570  and  572 . 
     As discussed above in connection with FIGS. 3,  7 - 9 ,  10 - 12 ,  13  and  15  the motor structures of the invention provide a relatively large volumetric region within their stator core assemblies which may be used for any of a variety of functional implementations. This typically permits the development of, for instance, tools which exhibit improved performance characteristics but with substantial reductions in size and weight This can become quite important where industrial personnel are working overhead with their arms extended upwardly carrying the weight of the tool as it is used. FIG. 30 demonstrates this advantageous feature wherein a d.c. PM motor according to the invention is incorporated within a nut runner or drill form of tool shown generally at  600 . Tool  600  incorporates a d.c. PM motor represented generally at  604  which is configured with a generally cylindrically-shaped base  606  which is machined to define annular ledges  608  and  610 . Ledge  608  is configured along with cylindrically upstanding base portion  612  extending to ledge  610  for receiving and supporting a stator core assembly represented in general at  614 . The ring-shaped base portion thereof is shown at  616 . Assembly  614  is formed of pressure-shaped processed ferromagnetic particles which form in conjunction with the ring-shaped base isotropic upstanding core components two of which are seen in sectional fashion at  618   a  and  618   b . The core components as at  618  are generally arranged in parallel relationship with the motor axis  620 . Axis  620  is seen to extend through the center of a relatively short motor shaft  622 . Shaft  622 , in turn, is supported within a cylindrical bearing cavity  624  formed within base  606 . In this regard, shaft  622  is supported by bearings  626  and  628 . Bearing  628  is supported at the bottom of the cavity  624 , while bearing  626  is supported between bearing spacer ring  630  and rotor spacer ring  632 . Base  606  may be formed, for example of aluminum. Motor shaft  622  is seen to extend through rotor spacer or washer  632  for fixed engagement with a rotor represented generally at  634 . Rotor  634  incorporates a non-magnetic rotor support portion  636  which may be formed of a high strength plastic. Portion  636  is generally cylindrically-shaped and fixed to shaft  622  and its outer cylindrical surface  638  is fastened to a ring-shaped back iron component  640 , the outward surface of which, in turn, supports a bonded rare earth magnet ring  642 . As before, each of the core components of the stator core assembly  614 , while arranged in generally parallel relationship to the motor axis  620 , is formed with a flux interaction surface represented generally at  644   a  and  644 b. Those surfaces are located and coextensive with the adjacent rotor confronting magnetic surfaces shown at  646  to define a working or functioning gap represented at  648 . Integrally formed with and extending from the flux interaction surfaces as at  644   a  and  644   b  are the winding regions as at  650   a - 650   b  which, in turn, extend a field winding length from spaced adjacency with the flux interaction surfaces to the ring-shaped back iron region  616 . As described earlier, the entire stator core assembly  614  is integrally formed using the noted pressure shaped processed ferromagnetic particles. The figure shows two of a plurality of polymeric bobbins as at  652   a  and  652   b  which are configured with field windings as shown respectively at  654   a - 654   b.    
     Base  606  is seen to be further configured with an internally disposed cylindrical functional implement cavity  656 . Note that this cavity as well as the motor shaft  622  extends centrally within the available volume within the stator core assembly  614 . Thus, compactness is achieved without loss of performance. Located within the cavity  656  is a gear head or planetary gear head assembly represented generally at  658 . Assembly  658  includes one planetary gear set comprised of a sun gear  660  fixed to motor shaft  620 , rotatable disc  662  and planetary gear  664 . Planetary gear  664  is enmeshed with sun gear  660  as well as an outer cylindrical gear  666 . Typically there are three planet gears as at  664  per planetary gear set. The secondary planetary gear set includes a sun gear  668  which is coupled to the disc  662  and is enmeshed with a planetary gear  670 . Gear  670  is enmeshed in turn with the cylindrical gear  666  and is coupled in driving relationship with a disc  672 . Disc  672 , in turn, is coupled to a drive output shaft  674 . Shaft  674  is supported within the cavity  656  by a bearing assembly  676  comprised of bearing  678  and  680 . These bearings are spaced apart by a spacer ring  682 . Base  606  further is coupled with an outer non-magnetic cowling  684  by machine screws as at  686  and  688 . Note that the cowling  684  is configured having a cylindrical internal cavity  690  to permit clearance for the field winding assemblies. 
     The motor architecture described above also can be implemented as an electricity generator. The latter term “generator” is intended to have meaning in the generic sense as including conventional generators as well as alternators. Referring to FIG. 31 a generator structure designed in accordance with the teachings of the invention is represented generally at  700 . Generator  700  is configured with a generally cylindrically-shaped generator base  702  formed of aluminum. Within the base  702  there is machined an annular groove represented generally at  704  exhibiting a rectangular cross section. Within this cross section, the outer annular surface  706  functions as a control for press fitting insertion thereinto of a stator core assembly represented generally at  708 . Assembly  708  is formed of pressure-shaped process ferromagnetic particles which form, in conjunction with a ring-shaped base or back iron region  710 , six isotropic upstanding core components shown in FIG. 32 at  712   a - 712   f . Each of the core components  712   a - 712   f  of the stator core assembly  708  is generally arranged in parallel relationship with a generator axis  714 . Returning to FIG. 31, axis  714  is seen extending through the center of the generator or rotor shaft  716 . Shaft  716 , in turn, is mounted within a bearing housing represented generally at  718 . Housing  718  is formed within the aluminum base  702  as a cylindrical portion or cavity  720  having shoulder defining countersunk regions for supporting two bail bearing structures  722  and  724 . In this regard, bearing  722  is located against an annular shoulder  726 , while bearing  724  nest against a similar annular shoulder  728 . Shaft  716  extends from a driven end  730  through a washer  732  for engagement with a rotor represented generally at  734 . Rotor  734  incorporates a non-magnetic rotor support portion  736  which may be formed with a high strength plastic. Portion  736  is generally cylindrically-shaped and fixed to shaft  716  and its outer cylindrical surface  738  is fashioned to a ring-shaped back iron component  740 , the outward surface of which, in turn, supports a bonded rare earth magnet ring  742 . Looking additionally to FIGS. 32 and 33, each of the core components of the stator core assembly  708 , while arranged in generally parallel relationship to the generator axis  714 , is formed with a flux interaction surface represented generally at  744   a - 744   f . As seen at flux interaction surfaces  744   a  and  744   d  in FIG. 31, those surfaces are located in spaced adjacency with and coextensive with the adjacent rotor confronting magnetic surfaces shown at  746  to define a working or functioning gap represented at  748 . Integrally formed with and extending from the flux interaction surfaces  744   a - 744   f  are the winding regions  750   a - 750   f  which extend, in turn, a field winding length from spaced adjacency with the flux interaction surfaces  744 a- 744   f  to the ring-shaped back iron region  710 . The entire stator core assembly  708  in integrally formed using the noted pressure-shaped processed ferromagnetic particles. Note that the external surface of the back iron region  710  is located in controlled surface adjacency with the outer annular surface  706  for fabrication control purposes. FIG. 31 shows two of the six polymeric bobbins as at  752   a  and  752   d  which are configured in conjunction with field windings as shown respectively at  754   a  and  754   d . This structuring is repeated for each of the core components  712   a - 712   f . Base  702  further is configured with an outer shoulder portion  756  which receives a corresponding flange of a cylindrical aluminum or polymeric generator side component  758 . Component  758 , in turn, extends to connection with a polymeric top and circuit support  760  having a circular opening  762  formed centrally there within. 
     For a single phase generator the number of magnetic poles or segments of the permanent magnet  742  will equal the number of poles or field windings. To provide a d.c. output for conventional generator applications, a rectifier is employed with the generator  700 . Looking to FIG. 34, a single phase arrangement is schematically portrayed with field winding  712   a - 712   f  arranged in serial fashion. The dots shown in the figure represent a start winding convention. Serially coupled field windings  712   a - 712   f  are seen coupled via leads  770  and  772  to a bridge rectifier represented generally at  774  and configured with diodes D 1 -D 4 . With the arrangement shown, the output of the generator is provided at leads  776  and  778  as a d.c. potential. A three phase configuration for the generator  700  is represented in FIG.  35 . In general, to provide for a three phase configuration, the rotor borne permanent magnets will, for the instant embodiment, be comprised of four or eight poles or magnetic segments. FIG. 35 illustrates a three phase circuit architecture wherein field windings  712   a  and  712   d  comprise one winding branch having a common connection  780  and extending to leads  782  and  784  incorporating complementary diodes D 5  and D 6 . The cathode side of diode D 5  provides one output at lead  786 . Windings  712   c  and  712   f  are seen coupled between common connections  780  and leads  788  and  790  incorporating respective complementary diodes D 7  and D 8 . The cathode side of diode D 8  is seen extending through lead  792  to output lead  786 , while the anode side of diode D 7  is coupled via lead  794  in combination with the anode of diode D 6  to output lead  796 . Finally, field windings  712   b  and  712   e  are seen connected via leads  798  and  800  to respective complementary diodes D 9  and D 10 . The anode side of diode D 9  is coupled to output lead  796 , while the cathode side of diode D 10  is coupled via lead  792  to output lead  786 . 
     Since certain changes may be made in the above described apparatus without departing from the scope of the invention herein involved, it is intended that all matter contained in the description thereof or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.