Light weight rotor and stator with multiple coil windings in thermal contact

• US 5,929,611 A
• Filed: 04/16/1997
• Issued: 07/27/1999
• Est. Priority Date: 09/14/1994
• Status: Expired due to Fees

• Current Assignee: Powermate Corporation (Pramac America LLC)
• Original Assignee: Coleman Company Incorporated (Newell Brands Inc.)
• Inventors: Scott, Harold C., Tally, Henry, Anderson, William J, Pandya, Kandarp I., Bednorz, Ardel R., Davis, Mitchell K., Johnson, G. Weylin
• Primary Examiner(s): Ramirez, Nestor
• Assistant Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US08/843,576
• Time in Patent Office: 832 Days
• Field of Search: 310/50, 310/184, 322/46, 322/32, 322/28, 322/25
• US Class Current: 322/46
• CPC Class Codes: F02B 2063/045 Frames for generator-engine sets
• CPC Class Codes: F02B 2063/046 Handles adapted therefor, e.g. handles or grips for movable units
• CPC Class Codes: F02B 63/04 for electric generators
• CPC Class Codes: F02B 63/044 the engine-generator unit being placed on a frame or in an housing
• CPC Class Codes: F02B 75/16 Engines characterised by number of cylinders, e.g. single-cylinder engines F02B75/26 takes precedence
• CPC Class Codes: F05C 2201/021 Aluminium
• CPC Class Codes: H02K 1/278 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 11/05 Rectifiers associated with casings, enclosures or brackets
• CPC Class Codes: H02K 21/48 Generators with two or more outputs
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32
• CPC Class Codes: H02K 7/1815 structurally associated with reciprocating piston engines general aspects of generating sets, e.g. housing, F02B63/04
• CPC Class Codes: H02M 1/0085 Partially controlled bridges
• CPC Class Codes: H02P 2101/45 for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 25/188 wherein the motor windings are switched from series to parallel or vice versa to control speed or torque
• CPC Class Codes: H02P 9/04 Control effected upon non-electric prime mover and dependent upon electric output value of the generator
• CPC Class Codes: H02P 9/30 using semiconductor devices

Abstract

A lightweight engine-driven generator set including a stator having at least first and second windings (preferably three-phase) and a rotor having a soft magnetic core and a plurality of high energy product permanent magnets, separated by consequence poles, disposed proximate the stator such that relative motion of the rotor and stator causes magnetic flux from the rotor to interact with and induce current in the stator windings. The first winding includes a predetermined number of turns corresponding to a first predetermined voltage output; and the second winding includes a predetermined number of turns corresponding to a second predetermined voltage output, the respective windings being grouped together as a unit and wound about the core such that the respective winding coils are wound in continuous close thermal contact with each other. The first winding generates a relatively high voltage, low amperage signal, and the second winding generates a relatively low voltage, high amperage signal; and a switch provides for selection of the desired output. Preferably the rotor is a hollow cylinder mounted on the engine shaft for rotation about the stator and such that the proper gap distance between rotor and stator is maintained during rotation of the rotor without bearings external to the engine. The low voltage, high amperage winding (or winding group) may be tapped to provide a selectable voltage output. Suitable rectifiers and inverters may be provided to effect selective DC and AC output signals.

Claims

1. Apparatus comprising a stator including at least one winding, and a rotor disposed relative to the stator such that relative motion of the rotor and stator causes magnetic flux from the rotor to interact with and induce current in the stator winding,

wherein the stator comprises:

a soft-magnetic core;

a first winding, including a predetermined number of turns corresponding to a first predetermined voltage output; and

a second winding, including a predetermined number of turns corresponding to a second predetermined voltage output;

the respective windings being grouped together as a unit and wound about the core such that the respective winding coils are wound in thermal contact with each other;

and wherein;

the rotor comprises a body of soft magnetic material with a plurality of permanent magnets in a surface disposed proximate to the stator;

the magnets have a predetermined surface area;

the magnets are mounted in insets formed in the rotor surface proximate to the stator;

the rotor surface proximate to the stator includes portions between the insets to form respective consequence poles, each consequence pole having a predetermined surface area;

the magnets are disposed within the insets, separated from adjacent consequence poles by a predetermined distance; and

the surface area of the magnets proximate the stator is greater than the surface area of the consequence poles proximate the stator.

2. The apparatus of claim 1 wherein the magnets are high energy product magnets.

3. The apparatus of claim 1 wherein:

the insets are symmetrically disposed in the rotor surface proximate to the stator;

the consequence poles are symmetrically disposed in the rotor surface proximate to the stator; and

the magnets are centrally disposed within the insets.

4. The apparatus of claim 1 wherein the distance separating the magnets from the consequence poles is greater than the distance separating the rotor surface from the stator.

5. The apparatus of claim 4 wherein the distance separating the magnets from the consequence poles is at least five times greater than the distance separating the rotor surface from the stator.

6. The apparatus of claim 1 wherein:

the first winding is a 3-phase star winding, each phase of the first winding including a predetermined number of turns corresponding to the first predetermined voltage output; and

the second winding is a 3-phase star winding, each phase of the second winding including a predetermined number of turns corresponding to the second predetermined voltage output;

the corresponding phases of the respective 3-phase windings being grouped together as a unit and wound about the core such that the corresponding phases of the respective 3-phase windings are in thermal contact corresponding phases of the respective 3-phase windings are in thermal contact with each other.

7. The apparatus of claim 6 wherein the first predetermined output voltage is on the order of 110 volts, and the second predetermined output voltage is on the order of 12 volts.

8. The apparatus of claim 6 wherein each phase of at least one winding includes a first portion defined by a tap to provide a third predetermined voltage output.

9. The apparatus of claim 8 further comprising:

a switch, for selectively effecting a connection to one of the second or third predetermined voltage outputs; and

a rectification circuit, receptive of signals from the switch for generating DC signals.

10. The apparatus of claim 8 wherein the first predetermined output voltage is on the order of 110 volts, the second predetermined output voltage is on the order of 24 volts, the third predetermined output voltage is on the order of 12 volts.

11. The apparatus of claim 1 wherein the first winding generates a relatively high voltage low amperage signal and the second winding generates a relatively low voltage high amperage signal.

12. The apparatus of claim 1 further comprising a rectification circuit, responsive to signals from the stator winding, for generating DC signals.

13. The apparatus of claim 12 wherein the apparatus includes:

respective output terminals; and

means for disabling the rectification circuit in response to a reverse polarity voltage in excess of a predetermined level, across the output terminals.

14. The apparatus of claim 13 wherein the apparatus further includes:

means for enabling the rectification circuit in response to voltage in excess of a predetermined level, across the output terminals.

15. The apparatus of claim 1 wherein:

the rotor comprises a hollow cylinder with the magnets mounted on the internal surface of the cylinder;

the stator is concentrically disposed within the cylinder; and

the rotor is mounted for rotation about the stator.

16. The apparatus of claim 15 further improved wherein the stator includes a central aperture, and the rotor is adapted for mounting on a shaft journaled through the stator central aperture.

17. The apparatus of claim 15 wherein the stator includes a plurality of windings.

18. The apparatus of claim 15 wherein the stator includes a first winding for generating a relatively high voltage low amperage signal and a second winding for generating a relatively low voltage high amperage signal.

19. The apparatus of claim 15 further improved wherein:

the first winding is a 3-phase star winding, each phase of the first winding including a predetermined number of turns corresponding to a second predetermined voltage output;

the second winding is a 3-phase star winding, each phase of the second winding including a predetermined number of turns corresponding to a second predetermined voltage output;

the corresponding phases of the respective 3-phase windings grouped together as a unit and wound about the core such that the corresponding phases of the respective 3-phase windings are in thermal contact with each other.

20. The apparatus of claim 19 further improved wherein each phase of at least one winding includes a first portion defined by a tap to provide a third predetermined voltage output.

21. The apparatus of claim 15 further comprising a rectification circuit, responsive to signals from the stator winding, for generating DC signals.

22. The apparatus of claim 21 wherein:

the apparatus further includes a fan mounted for rotation with the rotor;

said rotor, stator, rectification circuit, and fan are disposed within a housing, rotation of the fan creating a positive pressure within the housing;

the rectification circuit includes heat generating components; and

the housing includes respective apertures disposed in predetermined position relative to the heat generating components, creating an air flow over the components through the apertures to cool the components.

23. The apparatus of claim 22 wherein the fan comprises fan blades disposed on the exterior of the cylinder.

24. The apparatus of claim 15 wherein the rotor further includes fan blades disposed on the exterior of the cylinder.

25. Apparatus comprising:

a stator including at least one winding, and a rotor disposed relative to the stator such that relative motion of the rotor and stator causes magnetic flux from the rotor to interact with and induce current in the stator winding, the stator comprising;

a soft-magnetic core;

a first winding, including a predetermined number of turns corresponding to a first predetermined voltage output; and

a second winding, including a predetermined number of turns corresponding to a second predetermined voltage output;

the respective windings being grouped together as a unit and wound about the core such that the respective winding coils are wound in thermal contact with each other;

the first winding generating a relatively high voltage low amperage signal and the second winding generating a relatively low voltage high amperage signal;

a first rectification circuit, responsive to signals from the first stator winding, for generating a relatively high voltage low amperage DC signal; and

a second rectification circuit, responsive to signals from the second stator winding, for generating a relatively low voltage high amperage DC signal.

26. The apparatus of claim 25 wherein the first winding output voltage is on the order of 110 volts, and the second winding output voltage is on the order of 12 volts.

27. The apparatus of claim 25 further improved wherein:

the second winding includes a first portion defined by a tap to provide a third predetermined voltage output; and

the apparatus further comprises;

a switch, for selectively effecting a connection between the second rectification circuit and one of the second or third predetermined voltage outputs.

28. The apparatus of claim 25 wherein the surface area of the permanent magnets proximate the stator is greater than the surface area of the consequence poles proximate the stator by the ratio of the flux density produced by the permanent magnet to the allowed flux density of the consequence pole.

29. The apparatus of claim 28 wherein the magnets have a flux density of at least on the order of 5 kilogauss.

30. Apparatus comprising:

a stator including at least one winding, and a rotor disposed relative to the stator such that relative motion of the rotor and stator causes magnetic flux from the rotor to interact with and induce current in the stator winding, improved wherein the stator comprises;

a soft-magnetic core;

a first winding, including a predetermined number of turns corresponding to a first predetermined voltage output; and

a second winding, including a predetermined number of turns corresponding to a second predetermined voltage output;

the respective windings being grouped together as a unit and wound about the core such that the respective winding coils are wound in thermal contact with each other; and

a rectification circuit, responsive to signals from the stator winding, for generating DC signals;

said rotor, stator, and rectification circuit being disposed within a housing;

the housing being formed at least in part of electrically and thermally conductive material;

the rectification circuit including heat generating components connected to ground potential;

at least one of the rectification circuit components being electrically and thermally connected to the housing, such that the housing serves as a heat sink for the components and electrical ground for the rectification circuit.

31. The apparatus of claim 30 wherein:

the apparatus further includes a fan mounted for rotation with the rotor;

rotation of the fan creates a positive pressure within the housing;

the rectification circuit includes heat generating components; and

the housing includes respective apertures disposed in predetermined position relative to the heat generating components, creating an air flow over the components through the apertures to cool the components.

32. The apparatus of claim 30 further comprising an inverter, responsive to the DC signal, for generating an AC signal.

33. The apparatus of claim 32 further improved wherein the inverter comprises a variable frequency inverter, responsive to indicia of the current drawn from the inverter, for generating an AC signal having a frequency in accordance with the current drawn.

34. The apparatus of claim 32 further improved wherein the inverter comprises a variable frequency inverter, responsive to indicia of the DC voltage level, for generating an AC signal having a frequency in accordance with the DC voltage.

35. Apparatus comprising:

a stator including at least one winding, and a rotor disposed relative to the stator such that relative motion of the rotor and stator causes magnetic flux from the rotor to interact with and induce current in the stator winding, the stator comprising;

a soft-magnetic core;

a first winding, including a predetermined number of turns corresponding to a first predetermined voltage output; and

a second winding, including a predetermined number of turns corresponding to a second predetermined voltage output;

the respective windings being grouped together as a unit and wound about the core such that the respective winding coils are wound in thermal contact with each other;

an engine with a rotatable output shaft

the stator including a central aperture, the stator being fixedly mounted concentric with the engine shaft;

the rotor being mounted on the engine shaft sufficiently close coupled to the engine that the predetermined gap distance between rotor and stator is maintained during rotation of the rotor without bearings external to the engine.

36. The apparatus of claim 35 configured as a generator for generating a predetermined power output, wherein the ratio of the power output to the weight of the rotor is greater than 150 watts per pound.

37. The apparatus of claim 35 configured as a generator for generating a predetermined power output, wherein the ratio of the power output to the weight of the rotor is greater than 200 watts per pound.

38. The apparatus of claim 35 configured as a generator for generating a predetermined power output, wherein the ratio of the power output to the weight of the rotor is greater than 500 watts per pound.

39. The apparatus of claim 35 configured as a generator for generating a predetermined power output, wherein the ratio of the power output to the weight of the rotor is greater than 700 watts per pound.

40. The apparatus of claim 35 configured as a generator for generating a predetermined power output, wherein the ratio of the power output to the weight of the rotor is greater than 800 watts per pound.

41. The apparatus of claim 35 wherein the first winding generates a relatively high voltage low amperage signal and the second winding generates a relatively low voltage high amperage signal.

42. The apparatus of claim 35 further improved wherein:

the first winding is a 3-phase star winding, each phase of the first winding including a predetermined number of turns corresponding to the first predetermined voltage output; and

the second winding is a 3-phase star winding, each phase of the second winding including a predetermined number of turns corresponding to the second predetermined voltage output;

the corresponding phases of the respective 3-phase windings wound about the core such that the corresponding phases of the respective 3-phase windings are in thermal contact corresponding phases of the respective 3-phase windings are in thermal contact with each other.

43. The apparatus of claim 42 wherein the first predetermined output voltage is on the order of 110 volts, and the second predetermined output voltage is on the order of 12 volts.

44. The apparatus of claim 42 further improved wherein each phase of at least one winding includes a first portion defined by a tap to provide a third predetermined voltage output.

45. The apparatus of claim 44 further comprising:

a switch, for selectively effecting a connection to one of the second or third predetermined voltage outputs; and

a rectification circuit, receptive of signals from the switch for generating DC signals.

46. The apparatus of claim 44 further improved wherein the first predetermined output voltage is on the order of 110 volts, the second predetermined output voltage is on the order of 24 volts, the third predetermined output voltage is on the order of 12 volts.

47. The apparatus of claim 35 further comprising a rectification circuit, responsive to signals from the stator winding, for generating DC signals.

48. The apparatus of claim 47 wherein:

said rotor, stator, and rectification circuit, are disposed within a housing;

the housing is formed at least in part of electrically and thermally conductive material;

the rectification circuit includes heat generating components connected to ground potential; and

at least one of the rectification circuit components is electrically and thermally connected to the housing, such that the housing serves as a heat sink for the components and electrical ground for the rectification circuit.

49. The apparatus of claim 47 wherein:

the apparatus further includes a fan mounted for rotation with the rotor;

said rotor, stator, rectification circuit, and fan are disposed within a housing, rotation of the fan creating a positive pressure within the housing;

the rectification circuit includes heat generating components; and

the housing includes respective apertures disposed in predetermined position relative to the heat generating components, creating an air flow over the components through the apertures to cool the components.

50. The apparatus of claim 47 further comprising an inverter, responsive to the DC signal, for generating an AC signal.

51. The apparatus of claim 50 further improved wherein the inverter comprises a variable frequency inverter, responsive to indicia of current drawn from the inverter, for generating an AC signal having a frequency in accordance with the current drawn.

52. The apparatus of claim 50 further improved wherein the inverter comprises a variable frequency inverter, responsive to indicia of the DC voltage level, for generating an AC signal having a frequency in accordance with the DC voltage.

53. The apparatus of claim 35 further including a connection mechanism for a carrying strap.

54. The apparatus of claim 35 wherein the permanent magnets are high energy product magnets.

55. The apparatus of claim 35 wherein:

the magnets are disposed separated from adjacent consequence poles by a predetermined distance greater than the distance separating the rotor surface from the stator.

56. The apparatus of claim 55 further including:

a mounting frame having a foot portion and a transverse portion with first and second opposing sides;

an aperture formed in the frame transverse portion; and

wherein;

the engine is mounted on one side of the frame transverse portion overlying the foot, with the engine shaft extending through the aperture; and

the stator is mounted on the opposite side of the transverse portion concentric with the engine shaft; and

the rotor is mounted on the shaft laterally aligned with the stator.

57. The apparatus of claim 56 wherein the mounting frame is formed of a single sheet of material.

58. The apparatus of claim 56 wherein the mounting frame includes a handle portion.

59. The apparatus of claim 56 wherein the handle portion is adapted for connection to a shoulder strap.

60. The apparatus of claim 56 wherein the mounting frame is adapted for connection to a carrying strap.

61. The apparatus of claim 56 wherein:

the stator is generally annular with a central cavity; and

the rotor is coaxially disposed within the cavity.

62. The apparatus of claim 56 wherein:

the stator is generally cylindrical with a central axial bore;

the engine shaft extends through the bore;

the rotor includes a generally cylindrical central axial cavity and a hub; and

the rotor is mounted to the engine shaft at the hub, with the stator coaxially disposed inside the rotor cavity.

63. The apparatus of claim 35 further including:

a mounting frame having a foot portion and a transverse portion with first and second opposing sides;

an aperture formed in the frame transverse portion; and

wherein;

the engine is mounted on one side of the frame transverse portion overlying the foot, with the engine shaft extending through the aperture; and

the stator is mounted on the opposite side of the transverse portion concentric with the engine shaft; and

the rotor is mounted on the shaft laterally aligned with the stator.

64. The apparatus of claim 63 wherein the permanent magnets are high energy product magnets.

65. The apparatus of claim 63 wherein the mounting frame is formed of a single sheet of material.

66. The apparatus of claim 63 wherein the mounting frame includes a handle portion.

67. The apparatus of claim 66 wherein the handle portion is adapted for connection to a shoulder strap.

68. The apparatus of claim 63 wherein the mounting frame is adapted for connection to a carrying strap.

69. The apparatus of claim 63 wherein:

the stator is generally annular with a central cavity; and

the rotor is coaxially disposed within the cavity.

70. The apparatus of claim 63 wherein:

the stator is generally cylindrical with a central axial bore;

the engine shaft extends through the bore;

the rotor includes a generally cylindrical central axial cavity and a hub; and

the rotor is mounted to the engine shaft at the hub, with the stator coaxially disposed inside the rotor cavity.

71. Apparatus comprising:

a stator comprising;

a soft-magnetic core having, a central axial throughbore;

a first winding, including a predetermined number of turns corresponding to a first predetermined voltage output;

a second winding, including a predetermined number of turns corresponding to a second predetermined voltage output;

the respective windings being grouped together as a unit and wound about the core such that the respective winding coils are wound in thermal contact with each other;

a rotor disposed relative to the stator such that relative motion of the rotor and stator causes magnetic flux from the rotor to interact with and induce current in the stator winding, the rotor being disposed to rotate around the perimeter of the stator, the rotor comprising;

a cylindrical casing formed of soft-magnetic material, the casing having an internal cavity and an internal side wall; and

a plurality of alternating permanent magnets and consequence poles, disposed in the interior side wall of the casing;

an engine mount having a central axial stem with an internal bore of predetermined diameter, wherein the stator is disposed on the mount with the central axial stem received the central axial throughbore so that the central axial stem effects an interference fit with the central axial throughbore; and

an engine shaft journaled through the internal bore, the shaft having a smaller diameter than the internal bore, so that the engine shaft is rotatable in engine mount bore, and wherein the rotor is fastened to the engine shaft.

72. The apparatus of claim 71, further comprising fins formed on exterior side walls of the rotor casing to facilitate cooling.

73. Apparatus adapted to provide an output signal to a load, comprising:

a stator including at least one winding, and a rotor disposed relative to the stator such that relative motion of the rotor and stator causes magnetic flux from the rotor to interact with and induce current in the stator winding, improved wherein the stator comprises;

a soft-magnetic core;

a first winding, including a predetermined number of turns corresponding to a first predetermined voltage output; and

a second winding, including a predetermined number of turns corresponding to a second predetermined voltage output;

the respective windings being grouped together as a unit and wound about the core such that the respective winding coils are wound in thermal contact with each other

an engine with a rotatable output shaft, the engine rotating the shaft at a rotational speed in accordance with a throttle control;

a rectifier circuit, responsive to signals from the stator winding, for generating a DC signal;

an inverter, responsive to the DC signal, for generating an output signal of predetermined frequency; and

a throttle control system for selectively controlling the engine throttle in accordance with the output signal.

74. The apparatus of claim 73 further improved wherein the throttle control system comprises:

a sensor for generating indicia of load demand;

means for selectively generating a throttle control signal; and

an electromagnetic actuator mechanically coupled to the engine throttle, and responsive to the throttle control signal, for selectively varying the setting of the throttle.

75. The apparatus of claim 74 further improved wherein the electromagnetic actuator comprises:

a cylindrical magnet, magnetized through its length;

a non-magnetic push rod cooperating with the cylindrical magnet and the engine throttle;

an actuator winding wound around the push rod;

wherein the throttle control signal is selectively applied to the actuator winding to generate a magnetic interaction between the winding and the magnet and cause movement of the magnet and pushrod to vary the setting of the throttle.

76. The apparatus of claim 75 further improved wherein the throttle control signal is pulse width modulated and the width of the pulse determines the power of the electrical signal supplied to the winding.

77. The apparatus of claim 75, further improved comprising a fly-back diode provided across the winding.

78. Apparatus for generating a predetermined power output, comprising a rotor and a stator including a stator winding, wherein:

the rotor comprises a body of soft-magnetic material with a plurality of permanent magnets in a surface disposed proximate to the stator, separated from the stator by a predetermined gap distance, such that relative motion of the rotor and stator causes magnetic flux from the magnets to interact with and induce current in the stator winding;

the ratio of the power output to the weight of the rotor is greater than 150 watts per pound; and

the stator includes;

a soft-magnetic core;

a first 3-phase star winding, each phase of the first winding including a predetermined number of turns corresponding to a first predetermined voltage output; and

a second 3-phase star winding, each phase of the second winding including a predetermined number of turns corresponding to a second predetermined voltage output;

the corresponding phases of the respective 3-phase windings grouped together as a unit and wound about the core such that the corresponding phases of the respective 3-phase windings are in continuous thermal contact with each other.

79. The apparatus of claim 78 wherein the first predetermined output voltage is on the order of 110 volts, and the second predetermined output voltage is on the order of 12 volts.

80. The apparatus of claim 78 wherein each phase of at least one winding includes a first portion defined by a tap to provide a third predetermined voltage output.

81. The apparatus of claim 80 further comprising:

a switch, for selectively effecting a connection to one of the second or third predetermined voltage outputs; and

a rectification circuit, receptive of signals from the switch for generating DC signals.

82. The apparatus of claim 80 wherein the first predetermined output voltage is on the order of 110 volts, the second predetermined output voltage is on the order of 24 volts, the third predetermined output voltage is on the order of 12 volts.

83. The apparatus of claim 78 further comprising a rectifier, responsive to the first predetermined voltage output signal, and an invertor cooperating with the rectifier, for generating an AC signal.

84. The apparatus of claim 83 wherein the invertor comprises a variable frequency invertor, responsive to indicia of current drawn from the invertor, for generating an AC signal having a frequency in accordance with the current drawn.

85. The apparatus of claim 83 wherein the invertor comprises a variable frequency invertor, responsive to indicia of the rectifier output signal, for generating an AC signal having a frequency in accordance with the voltage of the rectifier output signal.

86. A generator for generating an AC signal to a load, the apparatus comprising:

a stator including at least one winding,

a rotor disposed relative to the stator such that relative motion of the rotor and stator causes magnetic flux from the rotor to interact with and induce current in the stator winding,

a rectifier circuit, responsive to current in the stator winding, for generating a DC signal; and

a variable frequency invertor, responsive to the DC signal and a control signal indicative of current drawn by the load, for generating the AC signal, the frequency of the AC signal being selectively varied in accordance with current drawn by the load.

87. The generator of claim 86 wherein the control signal indicative of current drawn by the load comprises indicia of the voltage level of the DC signal.

88. The apparatus of claim 86, further comprising:

a variable frequency inverter connected to generate an AC signal; and

means for extending the operating capability of the apparatus by varying the frequency of the AC signal in accordance with current drawn from the generator, to thereby accommodate extraordinary transient demands from loads.

89. Apparatus comprising a stator and a rotor, the stator including at least one winding, and the rotor comprising a body of soft-magnetic material with a plurality of permanent magnets in a surface disposed proximate to the stator, separated from the stator by a predetermined gap distance, such that relative motion of the rotor and stator causes magnetic flux from the magnets to interact with and induce current in the stator winding, wherein the permanent magnets are high energy product magnets with a predetermined surface area, and the magnets are mounted in insets formed in the rotor surface proximate to the stator, the rotor surface proximate to the stator includes portions between the insets to form respective consequence poles, each consequence pole having a predetermined surface area, an the magnets are disposed within the insets, separated from adjacent consequence poles by a predetermined distance, improved wherein:

the surface area of the permanent magnets proximate to the stator is greater than the surface area of the consequence poles proximate to the stator.

90. The apparatus of claim 89 further improved wherein the surface area of the permanent magnets proximate to the stator is greater than the surface area of the consequence poles proximate to the stator by the ratio of the flux density produced by the permanent magnet to the allowed flux density of the consequence pole.

91. The apparatus of claim 89 wherein the magnets have a flux density of at least on the order 5 kilogauss.

92. The apparatus of claim 89 wherein:

the insets are symmetrically disposed in the rotor surface proximate to the stator;

the consequence poles are symmetrically disposed in the rotor surface proximate to the stator; and

the magnets are centrally disposed within the insets.

93. The apparatus of claim 89 wherein the distance separating the magnets from the consequence poles is greater than the distance separating the rotor surface from the stator.

94. The apparatus of claim 93 further improved wherein the distance separating the magnets from the consequence poles is at least five times greater than the distance separating the rotor surface from the stator.

95. The apparatus of claim 89 further comprising an engine to rotate the rotor.

96. The apparatus of claim 89 wherein the stator is generally annular with a central aperture and the rotor is concentrically disposed for rotation within the aperture.

97. The apparatus of claim 89 further improved wherein the rotor comprises a hollow cylinder with the magnets mounted on an internal surface of the cylinder, and the stator is concentrically disposed within the cylinder.

98. The apparatus of claim 97 wherein the stator includes a central aperture, and the rotor is adapted for mounting on a shaft journaled through the stator central aperture.

99. The apparatus of claim 89 wherein the stator includes a plurality of windings.

100. The apparatus of claim 89 further improved wherein the stator includes:

a soft magnetic core;

a first 3-phase star winding, each phase of the first winding including a predetermined number of turns corresponding to a first predetermined voltage output; and

a second 3-phase star winding, each phase of the second winding including a predetermined number of turns corresponding to a second predetermined voltage output;

the corresponding phases of the respective 3-phase windings grouped together as a unit and wound about the core such that the corresponding phases of the respective 3-phase windings coils are wound in continuous thermal contact with each other.