Abstract:
Low cost high output wind alternators are disclosed that may be made by modifying existing windmills. The wind alternators of the present invention are brushless alternators that provide high power output without the need to employ rare earth magnets. The low cost high output wind alternators of the present invention employ one or more rotors of circular cross section having permanent magnets mounted around their periphery. The permanent magnets may be mounted to inner rotor surfaces, outer rotor surfaces or both. Stationary stator electromagnets are mounted close enough to the path of the rotating permanent magnets of the rotor to generate electric power. Electromagnet windings are cooled by allowing some of the air coming through the central portion of the windmill to pass over exposed electromagnet winding surfaces. The air cooled brushless alternators of the present invention may be used to add power generating capabilities to existing windmills.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This non-provisional application claims benefit of the provisional application filed on Aug. 28, 2009 having application number U.S. 61/275,404. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to windmills for generating electric power. More particularly this invention relates to air cooled power generating windmills employing brushless permanent magnet alternators. The power generating windmills of the present invention employ one or more rotors of circular cross section such as hoops and cylinders having permanent magnets mounted around the periphery. The permanent magnets may be mounted to inner rotor surfaces, outer rotor surfaces or both. Stationary stator electromagnets are mounted close enough to the path of the rotating permanent magnets of the rotor to generate electric power. Electromagnet windings are cooled by allowing some of the air coming through the central portion of the windmill to pass over exposed electromagnet winding surfaces. More cooling is automatically provided as needed by the greater air velocity during periods of high power generation. The air cooled brushless alternators of the present invention may be used to add power generating capabilities to existing windmills. 
         [0004]    2. Description of the Related Art 
         [0005]    This invention relates to windmills and more particularly relates to permanent magnet alternators for providing power generating capabilities to windmills. Windmills are devices that extract energy from moving air and convert that energy to rotary motion. This rotary motion can then be used to pump water, run machinery, and generate electricity. Windmills have been in use for centuries where their rotary motion has been used to run machinery for such uses as grinding wheat into flour. Windmills also enjoy a long history of pumping water. 
         [0006]    More recently, windmills have been used to generate electric power. Many of these wind generators employ specially designed couplings and gear reduction components to increase the RPM to a sufficient level so that the generator can extract significant power from the rotary motion of the blades. The need to increase the RPM value of the generator beyond the RPM value of the windmill blades arises from the fact that the ratio of impellor diameter to generator rotor diameter is usually quite large and may exceed a 50:1 ratio. 
         [0007]    Numerous electric generators and alternators may be employed to extract rotary power from the impellor shaft of windmills and produce electric power. A detailed description of electric generators and alternators will now be given. This description is based on the more thorough and complete description found in U.S. Pat. No. 6,967,417 titled “Variable Winding Generator” awarded to Fred Miekka and Peter Mackie included herein by reference. 
         [0008]    Generators use the principal of electromagnetic induction to convert the energy of motion into electricity. If an electric wire is moved through a magnetic field, or conversely if a magnetic field is made to change in the presence of such a conductor, an EMF or voltage will be induced in the conductor. The voltage induced in the conductor is determined by the following factors:
       (1) If the conductor is a wire in the form of a coil the greater the number of turns in the coil, the greater will be the EMF.   (2) The faster the conductor moves through the magnetic field the greater the EMF.   (3) The stronger the interacting magnetic field is the greater will be the induced EMF. If the conductor is stationary but the magnetic field changes (such as the case with permanent magnet alternators) the faster the rate of change the greater will be the induced EMF.       
 
         [0012]    When power is required such as for lighting applications, a connection is made between the power producing conductor of the generator and to the device. This causes a current to flow from the generator to the device. Whenever a generator delivers power to some device an associated mechanical drag on the moving parts of the generator results. The more power that is pulled from the generator the greater will be the mechanical requirements needed to keep the generator producing power. 
         [0013]    Numerous configurations of generators and alternators may be used with windmills to generate electric power. Included in this list are alternators employing two sets of windings, generators employing two sets of windings, generators employing permanent magnets and one set of windings, and permanent magnet alternators. With alternators employing two sets of windings, the stationary windings (stator windings) are mounted to the housing portion and are used to generate electric power. The rotary windings (rotor windings) are located on the rotor of the alternator and are energized by a direct current electric power source to create a continuous magnetic field. The power is provided to the rotor windings through a set of brushes that make contact with conductive metal rings (commutators). The commutators allow for supplying continuous electric current to the rotating rotor windings thereby maintaining their magnetic field. Generators employing two sets of windings use a similar system that has commutators that are segmented to time the activation of individual windings so that direct current results. With many direct current generators wired in this way power is input to the stator windings and the power generated is produced in the rotary windings. Electric generators may also be configured with permanent magnets attached to the generator housing producing the stator magnetic field thereby eliminating the need to provide input power. Brushes and segmented commutators are still required to provide for a timed output of electric current that is need to produce a direct current output. Brushless alternators are alternators that generate alternating current by employing rotating permanent magnets along with stationary electromagnets. This configuration is advantageous owing to the fact that no input power is required and no brushes or commutator is required. The magnets in the rotor spin past the power producing stationary electromagnets. The windmill generators of the present invention are brushless alternators and therefore have no brushes or commutators and do not require input power. The alternating current power may be used as is or may be rectified by diodes to produce an output of direct current. This output of direct current may then be fed into a capacitor or a battery to produce continuous direct current that is relatively free from voltage ripple. 
         [0014]    There are numerous brushless windmill alternators. Many of these employ a set of gears or pulleys that increase the RPM (revolutions per minute) of the alternator rotor. This simple approach provides the needed RPM values of the alternator rotor for producing power from the relatively low RPM of the windmill impellor shaft. While being relatively simple, gear boxes used in these systems require extra moving parts, produce unwanted noise, and reduce mechanical efficiency. Gear boxes may be eliminated from windmills employing permanent magnet alternators by placing the permanent magnets directly onto the impellor itself. This approach is outlined in U.S. Pat. No. 4,720,640 included herein by reference awarded to Bjorn M. S. Anderson and Reinhold H. Ziegler titled Fluid Powered Electrical Generator. U.S. Pat. No. 4,720,640 discloses a fluid powered electrical generator having an impellor rotor rotatively mounted on a central support structure. A toroidal outer support structure surrounds the impellor-rotor including a plurality of circumferentially spaced apart fluid dynamic blades. The outward ends of the blades are connected together by a rotor ring having permanent magnets attached. A second outer ring is fitted with electromagnets that have their pole faces in magnetic coupling proximity to the poles of the permanent magnets in the outer rotor ring of the impellor. The result is a wind generator capable of supplying a high output power requiring no added moving parts to the windmill. While being relatively straight forward, this system has the following drawbacks:
       (1) The mass of the permanent magnets on the periphery of the impellor adds considerable inertia to the system.   (2) The mass of the permanent magnets on the periphery of the impellor may generate excessive radial forces during high RPM conditions.   (3) The needed small gap of the permanent magnet poles to the electromagnet pole faces is difficult to produce and maintain (this may prove especially problematic for wind generators having impellors of considerable diameter.   (4) A high degree of structural strength is needed to keep the impellor and electromagnet assembly from vibrating excessively at certain RPM values.   (5) Excessive noise may result from excessive vibration.   (6) The rotor may not start spinning due to cogging effects resulting from the poles of the permanent magnets on the periphery of the impellor being attracted to the electromagnet stator poles.   (7) The large requirement for both permanent magnets and electromagnets adds cost and weight.   (8) The need to produce and maintain a high degree of trueness to impellors.
 
Despite these drawbacks, the overall simplicity of the system should result in a reduction of overall maintenance along with the ability to produce large amounts of power without the need to use more expensive and difficult to handle rare earth magnets.
       
 
         [0023]    A similar system for a fluid driven generator is disclosed in U.S. Pat. No. 5,696,419 awarded to Thomas G. Rakestraw and Alan E Rakestraw and is incorporated herein by reference. U.S. Pat. No. 5,696,419 discloses A shaftless permanent magnet alternator comprising of a rotor having permanent magnets attached to the periphery along with numerous C shaped electromagnets that straddle the rotor with their poles located within magnetic coupling proximity of the permanent magnets in the rotor. Numerous vanes are attached to the inner surface of the rotor for the purposes of converting fluid motion into rotary power. While being relatively compact in size, and eliminating some of the drawbacks of U.S. Pat. No. 4,720,640, the geometry of the vanes lends itself more toward high pressure low cross sectional fluid flow than to ambient wind. Additionally, the generator configuration disclosed in U.S. Pat. No. 5,696,419 does not provide a means for converting existing windmills into wind generators. 
         [0024]    Rare earth magnets are permanent magnets having unusually strong magnetic fields. They are called rare earth magnets because they use rare earth elements like neodymium in their compositions. Because rare earth magnets use expensive materials and expensive processes to produce they tend to be more expensive than other magnets made from materials like ceramic. Employing rare earth magnets in generators presents numerous problems in manufacturing. These problems arise from difficulties in handling these strong magnets. The use of rare earth magnets in generators presents special problems with design and assembly. There is a strong tendency for these magnets to pull strongly at iron core electromagnet pole faces. Cogging effects may also present themselves with the finished rotor making startup of the impellor of the wind generator difficult or even impossible. Additionally, these expensive and difficult to handle rare earth permanent magnets may rapidly lose their magnetic strength with heat. Despite these and other issues, rare earth permanent magnets are attractive candidates for use in windmill generators. One way of alleviating the cogging effects of these strong rare earth permanent magnets is to use coreless electromagnets. Coreless electromagnets are electromagnets that consist of a coil of wire but no iron core. Because coreless electromagnets have no iron in them, they do not suffer from issues of the strong rare earth permanent magnets pulling at them. It is generally understood that power producing electromagnets used in permanent magnet alternators require iron cores to concentrate and direct magnetic flux from the moving permanent magnets. Rare earth permanent magnets may have such intense magnetic fields that certain configurations do not require iron core electromagnets. 
         [0025]    One example uses vehicle brake disks for the permanent magnet rotor and coreless electromagnets as the stator. The electromagnet windings consist of coils of wire mounted in a planar configuration on a resin disk between two vehicle brake rotors. The vehicle brake rotors have rare earth magnets fastened to their surface within magnetic coupling proximity of the stationary coreless electromagnet windings on the resin disk. A more thorough description outlining the construction of a complete rare earth windmill alternator using vehicle brake disks may be found at the following web address. WWW.otherpower.com/davesmill.html This particular design is interesting owing to the fact that the entire windmill alternator can be made from readily available parts. 
         [0026]    Although simple and straightforward, because of its compact size, coupled with the fact that the stator electromagnet windings have no core and are encased in resin, the above described coreless rare earth permanent magnet brake disk alternator requires the use of rare earth permanent magnets and may suffer from excessive heat build up during times of high power generation. 
         [0027]    Despite numerous standard configurations for windmill generators and alternators there remains a need for lightweight permanent magnet windmill alternators that may be made by converting existing windmills, do not require the use of rare earth magnets, and have good heat dissipating properties. 
         [0028]    It is an object of this invention to provide a simple low cost method to convert existing windmills into wind alternators. 
         [0029]    It is a further object of this invention to provide wind alternators that are light in weight. 
         [0030]    It is a further object of this invention to provide wind alternators that are capable of high power output. 
         [0031]    It is a further object of this invention to provide wind alternators without brushes. 
         [0032]    It is a further object of this invention to provide wind alternators without gear reduction. 
         [0033]    It is a further object of this invention to provide wind alternators without the need to employ rare earth magnets. 
         [0034]    It is a further object of this invention to provide wind alternators that require minimal maintenance. 
         [0035]    It is a further object of this invention to provide wind alternators that do not produce excessive noise. 
         [0036]    Finally it is an object of this invention to provide wind alternators that do not overheat during high output conditions. 
       SUMMARY OF THE INVENTION 
       [0037]    This invention therefore proposes low cost high output permanent magnet alternators that can be attached directly to the impellor shaft portion of windmills. The high output alternators of the present invention employ a rotor consisting of one or more rings or cylinders of permanent magnets in magnetic coupling proximity to one or more stator windings. A portion of the air stream moving through the windmill is directed over the stator windings to provide cooling. The result is an efficient compact power generating windmill capable of high output without overheating. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0038]      FIG. 1  shows a sectional view of a permanent magnet alternator. 
           [0039]      FIG. 2  shows a cross sectional view of a wind generator of the prior art employing a ring of permanent magnets on the periphery of the impellor. 
           [0040]      FIG. 3  shows a profile view of a power generating windmill of the present invention employing a single hoop of permanent magnets along with c-core stator electromagnets. 
           [0041]      FIG. 4  shows a cross sectional view of an alternator for a power generating windmill of the present invention employing a single hoop having permanent magnets mounted on the outside periphery along with numerous electromagnets configured having their pole faces in an inward radial direction. 
           [0042]      FIG. 5  shows a cross sectional view of an alternator for a power generating windmill of the present invention employing a single hoop having permanent magnets mounted on the inside periphery along with numerous electromagnets configured having their pole faces in an outward radial direction. 
           [0043]      FIG. 6  shows a cross sectional view of an alternator for a power generating windmill of the present invention employing a single hoop having permanent magnets mounted on both the outside and inside periphery along with one set of electromagnets configured having their pole faces in an inward radial direction and another set of electromagnets configured having their pole faces facing outward in a radial direction. 
           [0044]      FIG. 7  shows a power generating windmill of the present invention employing two hoops of permanent magnets mounted on the outside periphery along with numerous c-core electromagnets. 
           [0045]      FIG. 8  shows a power generating windmill alternator of the present invention employing a hollow cylinder of permanent magnets on the outside surface along with numerous stator electromagnets. 
           [0046]      FIG. 9  shows a power generating windmill of the present invention employing a hoop of permanent magnets along with a small added impellor to aid in cooling of the electromagnet windings. 
           [0047]      FIG. 10  shows a power generating windmill of the present invention employing a hollow cylinder of permanent magnets along with a small added impellor to aid in cooling of the electromagnet windings. 
           [0048]      FIG. 11  shows a power generating windmill of the present invention employing a hoop of permanent magnets along with an added air scoop to aid in cooling of the electromagnet windings. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0049]      FIG. 1  shows a sectional view of a permanent magnet alternator. Permanent magnet alternator  2  is shown consisting of stator portion  4  and rotor portion  6 . Stator portion  4  consists of steel housing portion  8  along with numerous electromagnets  10 . Electromagnets  10  along with steel housing portion  8  form a magnetic stator circuit allowing magnetic flux to flow from one electromagnet to the next through steel housing portion  8 . Electromagnets  10  consist of core portion  12  and electromagnet windings  14 . Also shown are power output wires  16  for tapping electric power generated in electromagnet windings  14  of stator portion  6 . Also shown is shaft  18  which is fixedly attached to rotor portion  6 . Bearing  20  supports shaft  18  of rotor portion  6  while at the same time allowing shaft  18  and rotor portion  6  to rotate inside of housing portion  8 . Also shown are permanent magnets  22 . Permanent magnets  22  are shown fixedly attached to rotor portion  6 . Rotor portion  6  is made of steel and therefore conducts magnetic flux from one permanent magnet to the next thereby establishing a magnetic circuit. When shaft  18  is rotated inside of housing portion  8 , permanent magnets  22  pass by electromagnets  10 . Changes in the density and reversal of magnetic flux within the core portions of electromagnets  10  induces alternating current within electromagnet windings  14 . Power output wires  16  become energized and can be used to tap alternating current from alternator  2 . 
         [0050]      FIG. 2  shows a cross sectional view of a wind generator of the prior art employing a ring of permanent magnets on the periphery of the impellor. Windmill generator  24  is shown in accordance with U.S. Pat. No. 4,720,640. Windmill generator  24  is shown consisting of an outer stator portion  26  with numerous electromagnets  28 . Also shown are electromagnet windings  30  connected together by connecting wires  32 . Output leads  34  are used for delivering A.C. power. Inside of outer stator portion  26  is inner rotor portion  36 . Inner rotor portion  36  is shown consisting of turbine portion  38  having numerous permanent magnets  40  mounted on the outside periphery. Also shown is band  42 . Band  42  is made of a non-magnetic material and prevents permanent magnets  40  from detaching from turbine portion  38  during rotation. 
         [0051]    Turbine portion  38  is shown rotatably attached to outer stator portion  26 . Bearing  44  supports shaft  46  of turbine portion  38 . Spars  48  support bearing  44  within outer stator portion  26 . Also shown are vanes  50 . Vanes  50  impart rotational force to turbine portion  38  when acted upon by moving air. Air moving on vanes  50  imparts rotational force to inner rotor portion  36 . This causes inner rotor portion  36  to rotate. Rotation of inner rotor portion  36  causes permanent magnets  40  to move past electromagnets  28 . This resulting motion energizes electromagnet windings  30 . Power generated in electromagnet windings  30  flows through connecting wires  32  to output leads  34 . 
         [0052]    This particular wind generator configuration has numerous advantages compared with other wind generating systems. The main advantages are realized by the elimination of moving parts. The above described system has only one moving part, the rotor, no brushes to wear out or maintain, and the ability to generate large amounts of power without overheating. This particular system does have some disadvantages. These disadvantages were discovered when a prototype windmill was made and tested. The large number of permanent magnets required around the periphery resulted in the following issues.
       1. Increased expense associated with the number of permanent magnets and electromagnets required.   2. Increased weight from the large number of permanent magnets and electromagnets required.   3. Difficulties in balancing the rotor against excessive vibration, severe vibrational harmonics developed at certain speeds.   4. Cogging effects between the permanent magnets and electromagnets prevented the rotor from self starting.   5. High rotational inertia of the rotor having the permanent magnets mounted around the periphery further added to issues of self starting.   6. Difficulties were experienced in maintaining a close gap tolerance between the permanent magnets and the electromagnets. These difficulties resulted from several factors including.
           a. Manufacturing to a tight tolerance was met with difficulty.   b. Changes in the rotor dimension from thermal expansion and possibly expansion from moisture absorption.   c. Rotor expansion from high rotational forces during high speed rotation.   
           7. Excess noise generation.
 
It should be noted that large amounts of power could be extracted from the numerous permanent magnets interacting with the large number of electromagnets.
       
 
         [0063]    It is to be understood, that  FIG. 2  is a simplified drawing of the power generating portion of the wind generating system of U.S. Pat. No. 4,720,640. A more detailed description of this system is given in U.S. Pat. No. 4,720,640. 
         [0064]      FIG. 3  shows a power generating windmill alternator of the present invention employing a single hoop of permanent magnets along with numerous c-core stator electromagnets. Windmill  52  is shown in complete form. Unlike the windmill generator of  FIG. 2 , this system uses an ordinary windmill blade, turbine, or propeller to capture energy from moving air. In this way, many of the issues associated with the windmill generator of  FIG. 2  are overcome. Additionally, windmill generator  52  can be constructed out of readily available parts and may be used to modify existing windmills into windmill generators. This allows for low cost modification of existing windmills thereby reducing complications involved with constructing windmill generators. In short existing windmills such as aeromotor windmills can be modified with minimal added parts to manufacture windmill generators. Windmill generator  52  is shown in detail. Propeller blade  54  is shown fixedly attached to shaft  56 . Front bearing  58  supports the front portion of shaft  56  while at the same time allowing shaft  56  to rotate. Front bearing  58  is mounted into front bearing mount  60  which is secured to windmill base  66 . Rear bearing  62  supports the rear portion of shaft  56  and is secured to windmill base  66  with rear bearing mount  64 . Windmill base  66  is shown rotatably attached to mount  70  with rear bearing mount  64 . Directional fin  72  mounted to windmill base  66  so that windmill base  66  can rotate into the direction of the wind. Also shown is hoop  74 . Hoop  74  is shown having permanent magnets mounted around the periphery where maximum velocity occurs. Also shown are one of the electromagnets  78 . Electromagnets  78  are positioned so that permanent magnets  76  pass by in magnetic coupling proximity. Also shown is electromagnet mount  80 . Electromagnet mount  80  secures electromagnets  78  to windmill base  66 . When air moves over propeller blade  54 , shaft  56  rotates causing permanent magnets  76  on hoop  74  to pass by electromagnets  78 . The resulting changes and reversal of magnetic flux within electromagnets  78  induces A.C. power to be generated in electromagnet windings  82 . Electromagnet windings  82  become electrically energized. This electric power can be extracted from power output leads  84  which are in electrical contact with electromagnet windings  82 . 
         [0065]    The windmill generator of  FIG. 3  has the advantages outlined in U.S. Pat. No. 4,720,640 while at the same time eliminating the numerous issues previously mentioned. 
         [0066]      FIG. 4  shows a cross sectional view of an alternator for a power generating windmill of the present invention employing a single hoop having permanent magnets mounted on the outside periphery along with numerous electromagnets configured having their pole faces in an inward radial direction. This particular configuration may be used in the generator portion of the windmill generator of the present invention. Stator portion  88  of alternator  86  consists of steel housing portion  92  along with numerous electromagnets  94 . Electromagnets  94  along with steel housing portion  92  form a magnetic stator circuit allowing magnetic flux to flow from one electromagnet to the next through steel housing portion  92 . Electromagnets  94  consist of core portion  96  and electromagnet windings  98 . Also shown are power output wires  100  for tapping electric power generated in electromagnet windings  98  of stator portion  88 . Also shown is shaft  102  which is fixedly attached to a propeller for capturing wind energy (not shown). Shaft  102  is attached to hoop shaped rotor portion  90  with spars  108 . Bearing  104  supports shaft  102  of hoop shaped rotor portion  90  while at the same time allowing shaft  102  and hoop shaped rotor portion  90  to rotate inside of housing portion  92 . Also shown are permanent magnets  106 . Permanent magnets  106  are shown fixedly attached to hoop shaped rotor portion  90 . Hoop shaped rotor portion  90  is made of steel and therefore conducts magnetic flux from one permanent magnet to the next thereby establishing a magnetic circuit. When shaft  102  is rotated inside of housing portion  92 , permanent magnets  106  pass by electromagnets  94 . Changes in the density and reversal of magnetic flux within the core portions of electromagnets  94  induces alternating current within electromagnet windings  98 . Power output wires  100  become energized and can be used to tap alternating current from alternator  86 . 
         [0067]      FIG. 5  shows a power generating windmill of the present invention employing two hoops of permanent magnets along with numerous stator electromagnets. This particular configuration may be used in the generator portion of the windmill generator of the present invention. Stator portion  112  of alternator  110  consists of steel inner portion  116  along with numerous electromagnets  118 . Electromagnets  118  along with steel inner portion  116  form a magnetic stator circuit allowing magnetic flux to flow from one electromagnet to the next through steel housing portion  116 . Electromagnets  118  consist of core portion  120  and electromagnet windings  122 . Also shown are power output wires  124  for tapping electric power generated in electromagnet windings  122  of stator portion  112 . Also shown is shaft  126  which is fixedly attached to a propeller for capturing wind energy (not shown). Shaft  126  is attached to hoop shaped rotor portion  114  with spars  132 . Bearing  128  supports shaft  126  of hoop shaped rotor portion  114  while at the same time allowing shaft  126  and hoop shaped rotor portion  114  to rotate outside of steel inner portion  116 . Also shown are permanent magnets  130 . Permanent magnets  130  are shown fixedly attached to hoop shaped rotor portion  114 . Hoop shaped rotor portion  114  is made of steel and therefore conducts magnetic flux from one permanent magnet to the next thereby establishing a magnetic circuit. When shaft  126  is rotated outside of steel inner portion  116 , permanent magnets  130  pass by electromagnets  118 . Changes in the density and reversal of magnetic flux within the core portions of electromagnets  118  induces alternating current within electromagnet windings  122 . Power output wires  124  become energized and can be used to tap alternating current from alternator  110 . 
         [0068]      FIG. 6  shows a power generating windmill alternator of the present invention employing a hollow cylinder of permanent magnets along with numerous stator electromagnets. Wind powered alternator  134  consists of rotary portion  136  and stator portion  138 . Rotary portion  136  consists of steel hoop portion  140  along with permanent magnets  142  mounted on both the inside periphery of steel hoop portion  140  and the outside periphery of steel hoop portion  140 . Stator portion  138  consists of an outer portion  144  and an inner portion  146 . Outer portion  144  of stator portion  138  has numerous electromagnets  148  facing inward in a radial direction towards permanent magnets  142  located on the outside periphery of steel hoop portion  140 . Inner portion  146  of stator portion  138  has numerous electromagnets  150  facing outward in a radial direction towards permanent magnets  142  located on the inside periphery of steel hoop portion  140 . Electromagnet windings  152  are shown on both inner electromagnets  150  and outer electromagnets  148 . Electromagnet windings  152  provide electric alternating current power to output leads  154  in the usual way when permanent magnets  142  pass by their pole faces (not shown). Also shown is mount  156  for securing wind powered alternator  134 . Also shown is shaft  158  and spars  160  for providing rotary power to rotary portion  136 . End bearings (not shown) placed on both ends of shaft  158  hold rotary portion  136  in place while allowing shaft  158  to rotate. 
         [0069]    Wind generating alternator  134  takes advantage of generating electric power on both the inner surface and the outer surface of hoop shaped rotors employing permanent magnets thereby enabling relatively small generators to produce significant amounts of electric power during high wind conditions. 
         [0070]      FIG. 7  shows a power generating windmill of the present invention employing two hoops of permanent magnets mounted on the outside periphery along with numerous c-core electromagnets. Power generating windmill  162  is shown having two hoops of permanent magnets and two sets of electromagnets. Power generating windmill  162  is shown identical to the power generating windmill of figure three with an added hoop  164  of permanent magnets  166  along with an added set of power generating electromagnets  168 . Although only two hoops of permanent magnets are shown it should be noted that more permanent magnet hoops and sets of electromagnets may be added for increased power generating capacity. 
         [0071]      FIG. 8  shows a power generating windmill alternator of the present invention employing a hollow cylinder of permanent magnets on the outside surface along with numerous stator electromagnets. Windmill generator  170  is shown in detail. Propeller blade  172  is shown fixedly attached to shaft  174 . Front bearing  176  supports the front portion of shaft  174  while at the same time allowing shaft  174  to rotate. Front bearing  176  is mounted into front bearing mount  180  which is secured to windmill base  186 . Rear bearing  182  supports the rear portion of shaft  174  and is secured to windmill base  186  with rear bearing mount  184 . Windmill base  186  is shown rotatably attached to mount  190  with rear bearing mount  184 . Directional fin  192  mounted to windmill base  186  so that windmill base  186  can rotate into the direction of the wind. Also shown is cylinder  194 . Cylinder  194  is shown having permanent magnets mounted around the periphery where maximum velocity occurs. Also shown are one of the electromagnets  198 . Electromagnets  198  are positioned so that permanent magnets  196  pass by in magnetic coupling proximity. Also shown is electromagnet mount  200 . Electromagnet mount  200  secures electromagnets  198  to windmill base  186 . When air moves over propeller blade  172 , shaft  174  rotates causing permanent magnets  196  on cylinder  194  to pass by electromagnets  198 . The resulting changes and reversal of magnetic flux within electromagnets  198  induces A.C. power to be generated in electromagnet windings  202 . Electromagnet windings  202  become electrically energized. This electric power can be extracted from power output leads  204  which are in electrical contact with electromagnet windings  202 . 
         [0072]    The windmill generator of  FIG. 8  has the advantages outlined in U.S. Pat. No. 4,720,640 while at the same time eliminating the numerous issues previously mentioned. 
         [0073]      FIG. 9  shows a power generating windmill of the present invention employing a hoop of permanent magnets along with a small added impellor to aid in cooling of the electromagnet windings. Windmill  206  of  FIG. 9  is shown identical to windmill  52  of  FIG. 3  with the exception of an added impellor  208  for improving the efficiency of cooling of electromagnet windings under high power generating conditions. 
         [0074]      FIG. 10  shows a power generating windmill of the present invention employing a hollow cylinder of permanent magnets along with a small added impellor to aid in cooling of the electromagnet windings. Windmill  210  of  FIG. 10  is shown identical to windmill  170  of  FIG. 8  with the exception of an added impellor  212  for improving the efficiency of cooling of electromagnet windings under high power generating conditions. Added impellor  212  provides added airflow over the electromagnet windings in order to provide cooling. Another way to improve cooling of electromagnet windings under high power generating conditions is to direct the air stream over the electromagnet windings using cowling. This is illustrated in  FIG. 11 . It should be noted that the power generating windmills of the present invention may use electromagnets that have their windings somewhat exposed to the outside air. Depending on power output and configuration these power generating windmills may not require the use of added air flow to keep them from overheating. 
         [0075]      FIG. 11  shows a power generating windmill of the present invention employing a hoop of permanent magnets along with an added air scoop to aid in cooling of the electromagnet windings. Windmill  214  of  FIG. 11  is shown identical to windmill  52  of  FIG. 3  with the exception of an added cowling  216  for improving the efficiency of cooling of electromagnet windings under high power generating conditions. Added cowling  216  provides added airflow over the electromagnet windings by concentrating and redirecting air flow in order to provide cooling. 
         [0076]    Those skilled in the art will understand that the preceding embodiments of the present invention provide foundation for numerous alternatives and modifications. These other modifications are also within the scope of the limiting technology of the present invention. Accordingly, the present invention is not limited to that precisely shown and described herein but only to that outlined in the appended claims.