Abstract:
Apparatus and method for tuning the magnetic field of brushless motors and alternators to obtain efficient operation over a broad RPM range. The motor or alternator includes fixed windings (or stator) around a rotating rotor carrying permanent magnets. The permanent magnets are cylindrical and have North (N) and South (S) poles formed longitudinally in the cylindrical magnets. The magnets reside in magnetic conducing pole pieces (for example, low carbon or soft steel, and/or laminated insulated layers, of non-magnetizable material). Rotating the cylindrical permanent magnets inside the pole pieces either strengthens or weakens the resulting magnetic field to adjust the motor or alternator for low RPM torque or for efficient high RPM efficiency. Varying the rotor magnetic field adjusts the voltage output of the alternators allowing, for example, a windmill generator, to maintain a fixed voltage output. Other material used in the rotor is generally non-magnetic, for example, stainless steel.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to electric motors and generators and in particular to adjusting the orientation of fixed magnets in a rotor to obtain efficient operation at various RPM. 
     Brushless DC motors are often required to operate at various RPM but can only achieve efficient over a limited RPM range. 
     Further, generators and alternators are often required to operate over a broad RPM range. For example, automotive alternators operate at an RPM proportional to engine RPM and windmill alternators operate at an RPM proportional to wind speed. Unfortunately, known alternators generate electricity at a voltage proportion to RPM. Because RPM cannot be controlled, other elements are required to adjust the output voltage, adding inefficiency, complexity, and cost to the alternator systems. 
     Some designs have attempted to broaden RPM range using “field weakening” to allow the motor base speed (Kt or torque sensitivity) to be wound to be efficient at very low RPM, which is proportional to torque (lower RPM higher torque and vice versa), and to obtain efficient high RPM operation. Such field weakening can be in an Interior Permanent Magnet Synchronous Motor (IPMSM) or AC synchronous induction motors three to four times base speed with reasonable efficiency at high RPM but a motor with a ten times base speed RPM would have two and one-half to three and one-half times the starting torque of an AC motor. Unfortunately, field weakening with conventional methods can sacrifice efficiency and increase the complexity of controller algorithms and software. 
     In a generator/alternator application, the output voltage is proportional to magnetic flux strength requiring an inverter or separate electromagnetic exciter coil in automotive alternators that are only 60-70% efficient because of the very wide RPM range the alternators must operate over. Similar issues are present in wind power generation where variations in wind speed encountered resulting in operating inefficiencies. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention addresses the above and other needs by providing apparatus and method for tuning the magnetic field of brushless motors and alternators to obtain efficient operation over a broad RPM range. The motor or alternator includes fixed windings (or stator) around a rotating rotor carrying permanent magnets. The permanent magnets are cylindrical and have North (N) and South (S) poles formed longitudinally in the cylindrical magnets. The magnets reside in magnetic conducing pole pieces (for example, low carbon or soft steel, and/or laminated insulated layers, of non-magnetizable material). Rotating the cylindrical permanent magnets inside the pole pieces either strengthens or weakens the resulting magnetic field to adjust the motor or alternator for low RPM torque or for more efficient high RPM operation. Varying the rotor magnetic field adjusts the voltage output of the alternators allowing, for example, a windmill generator, to maintain a fixed voltage output. Other material used in the rotor is generally non-magnetic, for example, stainless steel. 
     In accordance with one aspect of the present invention, there are provided apparatus and methods to vary the flux strength of rotor/armature in an electric motor to provide improved starting torque and high RPM efficiency. 
     In accordance with another aspect of the present invention, there are provided apparatus and methods to vary the magnetic flux strength of rotor/armature in generator/alternator applications to control output voltage independent of RPM. Many known alternator applications cannot control alternator RPM, for example, automotive alternators which must operate at an RPM proportional to engine RPM and wind power generation which are subject to wind speed. Varying the magnetic flux strength of rotor/armature allows output voltage to be controlled independently of RPM thereby eliminating the need for an inverter or separate electromagnetic exciter coil. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
         FIG. 1A  is a side view of a reconfigurable electric motor according to the present invention. 
         FIG. 1B  is an end view of the reconfigurable electric motor. 
         FIG. 2  is a cross-sectional view of the reconfigurable electric motor according to the present invention taken along line  2 - 2  of  FIG. 1A . 
         FIG. 3  is a perspective view of a cylindrical two pole permanent magnet according to the present invention. 
         FIG. 4  is a perspective view of a cylindrical four pole permanent magnet according to the present invention. 
         FIG. 5A  is a side view of a tunable permanent magnet rotor according to the present invention, in a radially aligned configuration. 
         FIG. 5B  is an end view of the tunable permanent magnet rotor according to the present invention, in the radially aligned configuration. 
         FIG. 6A  is an end view of a tunable permanent magnet rotor according to the present invention, in the radially aligned configuration, with the permanent two pole magnets aligned for a maximum (or strong) magnetic field. 
         FIG. 6B  is an end view of a tunable permanent magnet rotor according to the present invention, in a radially aligned configuration, with the permanent two pole magnets aligned for a medium magnetic field. 
         FIG. 6C  is an end view of a tunable permanent magnet rotor according to the present invention, in the radially aligned configuration, with the permanent two pole magnets aligned for a minimum (or weak) magnetic field. 
         FIG. 7A  shows the strong magnetic field corresponding to  FIG. 6A . 
         FIG. 7B  shows the weak magnetic field corresponding to  FIG. 6C . 
         FIG. 8  is a side view of a tunable permanent magnet rotor according to the present invention, in a flux squeeze configuration. 
         FIG. 9  is an end view of the tunable permanent magnet rotor according to the present invention, in the flux squeeze configuration. 
         FIG. 10A  is an end view of a tunable permanent magnet rotor according to the present invention, in the flux squeeze configuration, with the permanent two pole magnets aligned for a maximum (or strong) magnetic field. 
         FIG. 10B  is an end view of a tunable permanent magnet rotor according to the present invention, in a flux squeeze configuration, with the permanent two pole magnets aligned for a medium magnetic field. 
         FIG. 10C  is an end view of a tunable permanent magnet rotor according to the present invention, in the flux squeeze configuration, with the permanent two pole magnets aligned for a minimum (or weak) magnetic field. 
         FIG. 11A  shows the strong magnetic field corresponding to  FIG. 10A . 
         FIG. 11B  shows the weak magnetic field corresponding to  FIG. 10C . 
         FIG. 12  is an end view of a tunable permanent magnet rotor according to the present invention, having pairs of the cylindrical two pole permanent magnets in the radially aligned configuration. 
         FIG. 13  is an end view of a tunable permanent magnet rotor according to the present invention, having pairs of the cylindrical two pole permanent magnets in the flux squeeze configuration. 
         FIG. 14  is an end view of a hybrid tunable permanent internal magnet and fixed external magnet rotor, in the radially aligned configuration, according to the present invention. 
         FIG. 15A  is an end view of the hybrid tunable permanent internal magnet and fixed external magnet rotor, in the radially aligned configuration, tuned for a maximum magnetic field according to the present invention. 
         FIG. 15B  is an end view of the hybrid tunable permanent internal magnet and fixed external magnet rotor, in the radially aligned configuration, tuned for a minimum magnetic field according to the present invention. 
         FIG. 16  is an end view of a hybrid tunable permanent internal magnet and fixed external magnet rotor, in the flux squeeze configuration, according to the present invention. 
         FIG. 17A  is an end view of the hybrid tunable permanent internal magnet and fixed external magnet rotor, in the flux squeeze configuration, tuned for a maximum magnetic field according to the present invention. 
         FIG. 17B  is an end view of the hybrid tunable permanent internal magnet and fixed external magnet rotor, in the flux squeeze configuration, tuned for a minimum magnetic field according to the present invention. 
         FIG. 18  is an end view of an element for constructing a laminated pole piece. 
         FIG. 18A  is a detail  18 A of  FIG. 18 . 
         FIG. 19A  is a side view of a first embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in a first magnet position. 
         FIG. 19B  is an end view of the first embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in the first magnet position. 
         FIG. 20A  is a side view of the first embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in a second magnet position. 
         FIG. 20B  is an end view of the first embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in the second magnet position. 
         FIG. 21A  is a side view of a second embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in a first magnet position. 
         FIG. 21B  is an end view of the second embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in the first magnet position. 
         FIG. 22A  is a side view of the second embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in a second magnet position. 
         FIG. 22B  is an end view of the second embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in the second magnet position. 
         FIG. 23A  is a side view of a third embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in a first magnet position. 
         FIG. 23B  is an end view of the third embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in the first magnet position. 
         FIG. 24A  is a side view of the third embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in a second magnet position. 
         FIG. 24B  is an end view of the third embodiment of apparatus for adjusting the cylindrical two pole permanent magnets in the second magnet position. 
         FIG. 25A  is an alternative gear apparatus for adjusting the positions of the cylindrical two pole internal permanent magnets of the hybrid tunable permanent internal magnet and fixed external magnet rotor, in the radially aligned configuration, according to the present invention. 
         FIG. 25B  is an alternative gear apparatus for adjusting the positions of the cylindrical two pole internal permanent magnets of the hybrid tunable permanent internal magnet and fixed external magnet rotor, in the flux squeeze configuration, according to the present invention. 
         FIG. 26A  is a side view of a biasing system for controlling magnet positions for a motor according to the present invention. 
         FIG. 26B  is an end view of the biasing system for controlling magnet positions for a motor according to the present invention. 
         FIG. 27A  is a side view of a biasing system for controlling magnet positions for a generator according to the present invention. 
         FIG. 27B  is an end view of the biasing system for controlling magnet positions for a generator according to the present invention. 
     
    
    
     Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
     A side view of a reconfigurable electric motor  10  according to the present invention is shown in  FIG. 1A , an end view of the reconfigurable electric motor  10  is shown in  FIG. 1B , and a cross-sectional view of the reconfigurable electric motor  10  taken along line  2 - 2  of  FIG. 1A  is shown in  FIG. 2 . The motor  20  includes stator windings  14  and a rotor  12  residing inside the stator windings  14 . The motor  10  is a brushless AC inductive motor including at least one permanent magnet  16  (see  FIGS. 3-7 ) in the rotor  12 , which magnet  16  may be adjusted to provide a weak magnetic field at startup for initial asynchronous operation and a strong magnetic field after startup for efficient synchronous operation. According to the present invention taken along line  2 - 2  of  FIG. 1A . 
     A perspective view of a cylindrical two pole permanent magnet  16  according to the present invention is shown in  FIG. 3  and a perspective view of a cylindrical four pole permanent magnet  16   a  according to the present invention is shown in  FIG. 4 . The poles of the magnet  16  and  16   a  run the lengths of the magnets as indicated by dashed lines. 
     A side view of a tunable permanent magnet rotor  12   a  according to the present invention, in a radially aligned configuration, is shown in  FIG. 5A  and an end view of the tunable permanent magnet rotor  12   a , in the radially aligned configuration, is shown in  FIG. 5B . The rotor  12   a  includes the magnets  16 , an inner pole piece  18 , outer pole pieces  20 , and non-magnetic spacer  22 . The pole pieces are a magnetically conducting but non-magnetizable material which conduct the magnetic field of the magnet  16  to create a rotor magnetic field. The spacer  22  separates the inner pole piece  18  from the outer pole pieces  20  and air gaps separate the outer pole pieces  20 . 
     An end view of a tunable permanent magnet rotor  12   a , with the permanent two pole magnets  16  aligned for a maximum (or strong) magnetic field  24   a  (see  FIG. 7A ) is shown in  FIG. 6A , an end view of a tunable permanent magnet rotor  12   a  with the permanent two pole magnets  16  aligned for a medium magnetic field is shown in  FIG. 6B , and an end view of a tunable permanent magnet rotor  12   a , with the permanent two pole magnets  16  aligned for a minimum (or weak) magnetic field  24   b  (see  FIG. 7B ) is shown in  FIG. 6C . In an electric motor, the alignment providing a strong magnetic field provide hi torque at low RPM and the alignment providing a weak magnetic field provide efficient operation at high RPM. In a generator, the output voltage may be adjusted by adjusting the magnet alignment allowing constant voltage in generators having varying RPM, such as automotive alternators and wind power generators. 
     The strong magnetic field  24   a  corresponding to  FIG. 6A  is shown in  FIG. 7A  and the weak magnetic field corresponding to  FIG. 6C  is shown in  FIG. 7B . 
     A side view of a tunable permanent magnet rotor  12   b  according to the present invention, in a flux squeeze configuration, is shown in  FIG. 8  and an end view of the tunable permanent magnet rotor  12   b  shown in  FIG. 9 . The rotor  12   b  includes the magnets  16 , pole pieces  21 , and air gaps  23 . The pole pieces are a magnetically conducting but non-magnetizable material which conduct the magnetic field of the magnet  16  to create a rotor magnetic field. The air gaps  23  separate the outer pole pieces  21 . 
     An end view of a tunable permanent magnet rotor  12   b , with the permanent two pole magnets  16  aligned for a maximum (or strong) magnetic field  24   a ′ (see  FIG. 11A ) is shown in  FIG. 10A , an end view of a tunable permanent magnet rotor  12   b  with the permanent two pole magnets  16  aligned for a medium magnetic field is shown in  FIG. 11B , and an end view of a tunable permanent magnet rotor  12   b , with the permanent two pole magnets  16  aligned for a minimum (or weak) magnetic field  24   b ′ (see  FIG. 11B ) is shown in  FIG. 10C . In an electric motor, the alignment providing a strong magnetic field provide hi torque at low RPM and the alignment providing a weak magnetic field provide efficient operation at high RPM. In a generator, the output voltage may be adjusted by adjusting the magnet alignment allowing constant voltage in generators having varying RPM, such as automotive alternators and wind power generators. 
     The strong magnetic field  24   a ′ corresponding to  FIG. 10A  is shown in  FIG. 11A  and the weak magnetic field corresponding to  FIG. 10C  is shown in  FIG. 11B . 
     An end view of a tunable permanent magnet rotor  12   c  according to the present invention, having pairs of the cylindrical two pole permanent magnets  16  in the radially aligned configuration is shown in  FIG. 12  and an end view of a tunable permanent magnet rotor  12   d  according to the present invention, having pairs of the cylindrical two pole permanent magnets  16  in the flux squeeze configuration is shown in  FIG. 13 . The present invention is not limited to single or pairs of magnets, and any number of magnets may be grouped as appropriate for the application. For example, three, four, five, or more magnets may replace the pairs of magnets in  FIGS. 12 and 13 . 
     An end view of a hybrid rotor  12   a ′ including tunable permanent internal magnets  16  and fixed external magnets  17 , in the radially aligned configuration, according to the present invention, is shown in  FIG. 14 . The combination of the tunable permanent internal magnets  16  and fixed external magnets  17  allows additional design of the rotor magnetic field. An end view of the hybrid tunable permanent internal magnet and fixed external magnet rotor  12   a ′, tuned for a maximum magnetic field, is shown in  FIG. 15A  and an end view of the hybrid tunable permanent internal magnet and fixed external magnet rotor  12   a ′ tuned for a minimum magnetic field is shown in  FIG. 15B . 
     An end view of a hybrid rotor  12   b ′ including tunable permanent internal magnets  16  and fixed external magnets  17 , in the flux squeeze configuration, according to the present invention, is shown in  FIG. 16 . The combination of the tunable permanent internal magnets  16  and fixed external magnets  17  allows additional design of the rotor magnetic field. An end view of the hybrid tunable permanent internal magnet and fixed external magnet rotor  12   b ′, tuned for a maximum magnetic field, is shown in  FIG. 17A  and an end view of the hybrid tunable permanent internal magnet and fixed external magnet rotor  12   b ′ tuned for a minimum magnetic field is shown in  FIG. 15B . 
     An end view of an element  30  for constructing a laminated pole piece is shown in  FIG. 18  and detail  18 A of  FIG. 18  is shown in  FIG. 18A . Rotors are often constructed from laminating a multiplicity of elements  30 , each element  30  coated by an electrical insulation. The element  30  has radius Rr, c round cutouts  32  for the cylindrical magnets  16  having a radius Rm, and air gaps having a width Wag  34 . 
     A side view of a first embodiment of apparatus  40   a  for adjusting the cylindrical two pole permanent magnets  16  in a first magnet position is shown in  FIG. 19A , an end view of the apparatus  40   a  for adjusting the cylindrical two pole permanent magnets in the first magnet position is shown in  FIG. 19B , a side view of the apparatus  40   a  for adjusting the cylindrical two pole permanent magnets  16  in a second magnet position is shown in  FIG. 20A , and an end view of the apparatus  40   a  for adjusting the cylindrical two pole permanent magnets in the second magnet position is shown in  FIG. 20B . The apparatus for adjusting  40   a  includes a linear motor  42  which is preferably a stepper motor, a shaft  48  actuated axially by the linear motor  42 , and ring  46  axially actuated by the shaft  48 , and an arm  44  actuated by the ring  46  and connected to one of six toothed racks  52 . The toothed racks  52  engaged gears  50  attached to the magnets  16  to rotate the magnets  16 . Actuation of the shaft  48  to the right pulls the toothed rack  52  radially in and actuation of the shaft  48  to the left pushed the toothed rack  52  radially out, thereby directly rotating the magnets with gears  50  directly engaging the toothed rack  52 , and the remaining magnets  16  are coupled to the actuation by the toothed racks between the adjacent gears  50 . 
     A side view of a second embodiment of apparatus  40   b  for adjusting the cylindrical two pole permanent magnets  16  in a first magnet position is shown in  FIG. 21A , an end view of the apparatus  40   b  for adjusting the cylindrical two pole permanent magnets in the first magnet position is shown in  FIG. 21B , a side view of the apparatus  40   b  for adjusting the cylindrical two pole permanent magnets  16  in a second magnet position is shown in  FIG. 22A , and an end view of the apparatus  40   b  for adjusting the cylindrical two pole permanent magnets in the second magnet position is shown in  FIG. 22B . The apparatus for adjusting  40   b  includes the linear motor  42  which is preferably a stepper motor, a shaft  48  actuated axially by the linear motor  42 , and ring  46  axially actuated by the shaft  48 , and a bent elbow  45  actuated by the ring  46  and connected to one of six toothed racks  52 . The bent elbow  45  is biased to a bent position, for example, with a 90 degree bend. When the ring  46  moves to the right to release the bent arm  45 , the bent arm  45  relaxes to the bent position and pulls the toothed rack  52  radially in. When the ring  46  moves to the left to exert force on the bent arm  45 , the bent arm  45  straightens and pushes the toothed rack  52  radially out. The toothed racks  52  engaged gears  50  attached to the magnets  16  to rotate the magnets  16 . Actuation of the linear motor  42  to the right thus pulls the toothed rack  52  radially in and actuation of the linear motor  42  to the left pushed the toothed rack  52  radially out, thereby directly rotating the magnets  16  with gears  50  directly engaging the toothed rack  52 , and the remaining magnets  16  are coupled to the actuation by the toothed racks  52  between the adjacent gears  50 . 
     A side view of a third embodiment of apparatus  40   c  for adjusting the cylindrical two pole permanent magnets  16  in a first magnet position is shown in  FIG. 23A , an end view of the apparatus  40   c  for adjusting the cylindrical two pole permanent magnets in the first magnet position is shown in  FIG. 23B , a side view of the apparatus  40   c  for adjusting the cylindrical two pole permanent magnets  16  in a second magnet position is shown in  FIG. 24A , and an end view of the apparatus  40   c  for adjusting the cylindrical two pole permanent magnets in the second magnet position is shown in  FIG. 24B . The apparatus for adjusting  40   c  includes the linear motor  42  which is preferably a stepper motor, a shaft  48  actuated axially by the linear motor  42 , a first piston  47  connected to the shaft  48  and a second piston  49  in fluid communication with the piston  47  and connected to one of the six toothed racks  52 . When the piston  47  moves to the right the second piston  49  is drawn radially in and the toothed rack  52  is pulled radially in. When the ring  46  moves to the left the piston  47  moves to the left and the piston  49  moves radially out and pushes the toothed rack  52  radially out. The toothed racks  52  engaged gears  50  attached to the magnets  16  to rotate the magnets  16 . Actuation of the linear motor  42  to the right thus pulls the toothed rack  52  radially in and actuation of the linear motor  42  to the left pushed the toothed rack  52  radially out, thereby directly rotating the magnets  16  with gears  50  directly engaging the toothed rack  52 , and the remaining magnets  16  are coupled to the actuation by the toothed racks  52  between the adjacent gears  50 . 
     Additional gear apparatus according to the present invention for adjusting the positions of the cylindrical two pole internal permanent magnets  16  of the hybrid tunable permanent internal magnet and fixed external magnet rotor, in the radially aligned configuration, is shown in  FIG. 25A . Small magnet gears  50  are fixed to an end of each magnet  16 . A large center gear  51  engages each of the small magnet gears  50  and causes each of the magnets  16  to maintain approximately (some gear lash may exist as long as the magnets are closely aligned) the same alignment and may be turned to adjust the alignment of the magnets  16  from the weak field to the strong field. 
     Additional gear apparatus for adjusting the positions of the cylindrical two pole internal permanent magnets of the hybrid tunable permanent internal magnet and fixed external magnet rotor, in the flux squeeze configuration, according to the present invention is shown in  FIG. 25B . A small center gear  51   a  engages alternate ones of the small magnet gears  50 , and the small gears  50  engage each adjacent gear  50 , and causes each of the magnets  16  to maintain approximately (some gear lash may exist as long as the magnets are closely aligned) the same alignment and may be turned to adjust the alignment of the magnets  16  from the weak field to the strong field. 
     A side view of a biasing system for controlling magnet positions for a motor according to the present invention is shown in  FIG. 26A  and an end view of the biasing system for controlling magnet positions for the motor through wires  70  is shown in  FIG. 26B . A control  64  converts single phase DC voltage from a source  68  to three phase trapezoidal or sinusoidal wave form for a three phase motor. One DC input line to a field coil  60  used to create an electromagnetic field proportional to a load on the motor. The field coil  60  has very low resistance and does not reduce input voltage to the motor or increase resistance appreciably. The field acts on a disk  62  and pushes the disk to the left against the bent elbow  45  to rotate the magnets  16 . 
     As the motor load increases, the electromagnetic field is increased proportionally with load, the calibrated load is just slightly less than required to overpower the rotation of the magnets  16 , the tipping circuit  66  is a shunting controller which provides a small current that added to the electromagnetic force of the bias armature  62  provides the final force to control the rotation of magnets  16  which controls the magnetic field of the rotor. The controller  64  is preferably an inverter type which converts single phase DC to a three phase wave form which energizes the stator fields to rotate the rotor. 
     The biasing actuator comprises the ultra low resistance coil  60  and armature  62  which produces force proportional to the load current that forces against the inherent nature of magnets  16  to rest in the weak magnetic field position. The tipping circuit  66  is a low force trigger control that contributes an extra current to the biasing actuator which can rotate the magnets  16  to adjust magnetic field to either strong or weak positions using very little electrical power. 
     A side view of a biasing system for controlling magnet  16  positions for a generator according to the present invention is shown in  FIG. 27A  and an end view of the biasing system for controlling magnet  16  positions for a generator is shown in  FIG. 27B . The generator may be driven to create the phase, or any phase, of power as a generator/alternator. 
     The output of generator/alternator phase power is generally passed through a six diode array  72  which converts the multi phase currents to single phase DC. The output of one of the output DC lines are diverted into the low resistance biasing coil  60  and armature  62  which create an opposing force against the natural rotation of the magnets  16  to the weak field position. In the same fashion as the motor configuration of  FIGS. 26A and 26B , the tipping control provides the little extra current to the coil  60  and armature  62  to overcome magnet force to control the position of rotation of magnets and magnetic field. The tipping circuit controller is an electronic transistor type switch which can provide a variable amount of power to be added to the biasing force of the coil  60  and armature  62 . 
     While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.