LIGHT WEIGHT GENSET

Abstract: A machine comprising a stator and a rotor, where the stator includes at least one winding and the rotor comprises a body of soft magnetic material with a plurality of permanent magnets in a surface disposed proximate to the stator, with intervening consequence poles, where 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. Also disclosed is a stator comprising a soft magnetic core with respective three-phase star windings corresponding to different predetermined voltage outputs with the corresponding phases of the respective three-phase windings grouped together as a unit and wound about the core such that the corresponding phases of the respective three-phase windings are in continuous thermal contact with each other. Also disclosed is the use of a variable frequency invertor responsive to a DC signal generated in the stator winding, and a control signal indicative of current drawn by a load on the device for generating an AC signal, where the frequency of the AC signal is selectively varied in accordance with current drawn by the load. In another embodiment, the rotor comprises a hollow cylinder with magnets mounted on the internal surface of the cylinder with the stator concentrically disposed within the cylinder. Also disclosed is a governor for selectively controlling the engine throttle in accordance with the generator output signal.

Description: TITLE: LIGHT WEIGHT GENSET BACKGROUND OF INVENTION The present invention relates to lightweight portable electrical generators. In general, portable DC generators are known. Portable generators commonly comprise a conventional diesel or gasoline powered engine having a crankshaft coupled to a generator. The generator includes a stationary stator, and a rotor disposed for rotation with the engine shaft. The rotor generates a magnetic field. As the magnetic field intercepts windings on the stator, electrical current is induced. The induced current is typically applied to a bridge rectifier, sometimes regulated, and provided as an output. Examples of such prior art generators include the Generac G1000 (950 watts and 49 pounds), the Honda EX1000 (1000 watts and 57 pounds) and the Yamaha EF1000 (1000 watts and 55 pounds). While typically not found in portable units, an AC output can be provided by applying the DC signal to an inverter. While referred to as portable, the prior art generator units tend to be heavy and unwieldy, or are incapable of providing sustained power sufficient for typical uses. Further, the prior art units typically provide either a relatively low amperage, high voltage (e.g., 115 volts) output, or a relatively low voltage, high amperage output (e.g., 12 or 24 volts, at from 25 to 200 amperes) and weigh from approximately 40 to 65 pounds, dry weight. In many instances, however, it is desirable to have both high voltage low current outputs, e.g., to run lights or power tools, and a low voltage high amperage output for, e.g., charging batteries or jump starting a car from a unit that is easily carried by one person using a shoulder strap. SUMMARY OF THE INVENTION. The present invention provides a truly lightweight generator capable of providing sustained power sufficient for typical uses. In accordance with one aspect of the present invention, a light weight generator is implemented employing a rotor utilizing high energy product permanent magnets. In accordance with another aspect of the present invention, the rotor is mounted directly on the engine shaft. The rotor is sufficiently close coupled to the engine that an air gap between the stator and rotor is maintained without bearings other than those normally employed in the engine. In accordance with another aspect of the present invention, the rotor is of multiple pole design with half of the poles consisting of high density magnets and the other half of the poles consisting of consequence poles, therefore obtaining maximum use of the high density magnets. In accordance with another aspect of the present invention, a multi-winding stator is employed to provide both low voltage high amperage output, e.g., for battery charging, and a high voltage low amperage output, e.g., for operating lights and power tools. In accordance with another aspect of the present invention, two alternative low voltage high amperage outputs may be provided, e.g., 12 volts and 24 volts. In accordance with another aspect of the present invention, the ratio of the generator power output to rotor weight is in excess of 150 or 200, preferably in excess of 500, more preferably in excess of 700, and most preferably in excess of 800 watts per pound. BRIEF DESCRIPTION OF THE DRAWING. The present invention will hereinafter be described in conjunction with the figures of the appended drawing wherein like designations denote like elements and: FIGURE 1 is a pictorial illustration of the light weight portable genset in accordance with aspect of the present invention; FIGURE 2 is a partial sectional side view of the genset of FIGURE 1 ; FIGURE 3 is an exploded pictorial view of the engine, frame and mounting plate of the genset of FIGURE 1; FIGURE 4 is an exploded view of the generator unit of the genset of FIGURE 1 ; FIGURE 5 is a partially cut-away pictorial view of the generator unit housing and control circuitry board; FIGURE 5A is an inside view of an alternative version of the generator unit housing; FIGURE 6 is a schematic diagram of the stator windings; FIGURE 7 A is a block schematic of the stator windings and control circuitry; FIGURE 7B is a block schematic of the control circuitry of the genset of FIGURE 1; FIGURE 7C is a schematic diagram of the control circuitry; FIGURES 8A, 8B, 8C and 8D are front, side sectional, and exploded front views of a rotor in accordance with one aspect of the present invention; FIGURE 9 is a block schematic of a control circuit including an inverter; FIGURE 9A discloses suitable regulators for the current of FIGURE 9. FIGURE 10 is a schematic of the pre-phase regulator, single phase bridge at signal supply of the circuit FIGURE 9. FIGURE 11 is a schematic of a suitable inverter control section. FIGURES 11A - 1 IF are a schematic memory map and flow chart of the inverter operation. FIGURE 12 is a schematic diagram of a basic power converter. Paragraph FIGURE 13 is a diagram of the output wave form of the inverter of FIGURE 9 employing the basic power converter FIGURE 12. FIGURE 14 is an output wave form closely simulating a sign wave. FIGURES 15 and 15 A are schematics of alternative auxiliary coil circuits utilized in generating a wave form of FIGURE 14. FIGURE 16 is a schematic diagram of a power conversion circuit suitable for generating the wave form of FIGURE 14. FIGURE 17 is a schematic of an alternative power conversion circuit for generating the wave form of FIGURE 14. FIGURES 18A and 18B are schematic illustrations of a throttle control in respective states. FIGURES 19A and 191 B are an exploded side sectional view of an alternative generator assembly using an external rotor, and a top view of the external rotor, respectively. DETAILED DESCRIPTION OF A PREFERRED EXEMPLARY EMBODIMENT. Referring to FIGURES 1 and 2, a lightweight portable generator in accordance with the present invention comprises an engine 12, a high output miniature generator unit 14, and a mounting frame 16. As best seen in FIGURES 2 and 3, engine 12 suitably includes a shaft 200 extending outwardly from a shoulder 42. Engine 12 may be any small high RPM engine with a high horsepower to weight ratio capable of turning a shaft. In the preferred embodiment, engine 12 is a 2.0 horsepower, two-cycle internal combustion engine, having a displacement of 3 cubic inches and weighing 7 1/2 pounds, such as a Tecumseh TC300. Referring now to FIGURES 1, 2 and 3, frame 16 provides a lightweight common mount for engine 12 and generator unit 14. Frame 16 is suitably formed of a lightweight rigid, electrically and thermally conductive material such as, for example, aluminum. In the preferred embodiment, an aluminum sheet is bent to provide foot 162, upright 164 and handle 166 portions of frame 16. The aluminum sheet is bent at a predetermined distance from one end to form foot 162, and perpendicular upright section 164. Handle 166 suitably comprises a first portion 167 bent from upright 164 to overlay foot 162; an upright section 168; and a forwardly facing lip 169 preferably angled, which cooperate to form a channel 170 into which an operator's finger may fit, to facilitate carrying the unit. If desired, handle 166 may be adapted to accommodate a strap or a light. For example, respective apertures 172 are formed through the lip of handle 166 at either side through which suitable clips of a strap 18 are received. Respective apertures 172A are formed through the lip of handle 166 for the mounting of a flood light. As will hereinafter be described, engine 12 and generator unit 14 are mounted on opposing sides of frame upright 164. As best seen in FIGURES 2 and 3, engine 12 is mounted to upright 164, overlying foot 162. A mounting plate 204 is interposed between engine 12 and frame upright 164 to provide structural strength to upright 164, and provide a medium for mounting engine 12 and the stator 210 to frame 16. To facilitate mounting of engine 12 and stator 210, plate 204 suitably includes first and second sets of apertures 309 and 310. Apertures 309 are suitably disposed in registry with corresponding apertures 311 (suitably countersunk) in frame upright 164, and threaded bores 313 in motor flange 202. Engine 12 is suitably fixed to upright 164 by a predetermined number (e.g. 4) of screws 308 (FIGURE 3) which are journaled through apertures 311 in upright 164, and apertures 309 in mounting plate 204, and are threaded into bores 313 motor flange 202. As shown in FIGURE 3 mounting plate 204 can, if desired, be extended upward to the bend of frame 16 between upright 164 and handle 166 to add mechanical strength to upright section 168 for mounting an optional flood light. If desired, a mounting block 206, suitably a soft rubber block to absorb vibration, may be interposed between foot 162, and motor 12, at the distal end of foot 162. If desired, rectangular aperture 172(b) may be provided in foot 162 to accommodate an optional lock kit. As previously discussed, apertures 310 are suitably threaded to facilitate mounting of the generator stator 210. Accordingly, plate 204 is suitably formed of a rigid material sufficiently thick to accommodate threaded apertures 310, such as, e.g. a 10-gauge plate. Referring now to FIGURES 2, 3 and 4, generator unit 14 preferably comprises a stator 210, a rotor 220, a fan shaft extension 230, a fan 240 and electronic control circuitry 250, all disposed within a housing 260 and top plate 282. Stator 210 is disposed concentrically with engine shaft 200, offset by a predetermined distance from frame upright 164. More specifically, stator 210 is fixedly mounted to frame upright 164 (and hence engine 12), and concentricity with engine shaft 200 maintained, by respective bolts 212. An offset from upright 164 is maintained by respective spacers 214. Bolts 212 extend through bores in stator 210, spacers 214, apertures 315 in frame 164, and are threaded into holes 310 in plate 204. As previously noted, plate 204 provides the structural integrity for mounting stator 210. As will be more fully discussed, in conjunction with FIGURES 6 and 7A, Stator 210 preferably includes a polarity of three-phase windings to generate first and second low-voltage, high-amperage outputs, e.g., a high-voltage, low-current output, preferably wound with the respective coils of each phase grouped together, and concurrently wound about a laminate core as a unit to provide particularly advantageous heat dissipation characteristics. Referring briefly to FIGURE 6, stator 210 suitably comprises two 3-phase windings, and a single-phase control coil that is wound together with the first phase of each 3-phase winding. More specifically, stator 210 includes a first and second 3-phase star windings 602 and 604, and single phase central winding 605 (wound together with the first phase windings). First winding 602 suitably provides a high voltage, low current output and is formed of a relatively small diameter, e.g., 24 gauge wire. Winding 604 suitably provides respective low-voltage (e.g. 12 and 24 volt), high current output. Each phase of winding 604 suitably includes a first portion 606, defined by a tap to provide a first low voltage (e.g. 12- volt) high current output, and a second portion 608, from which a second low-voltage, (e.g., 24-volt), high-current output is taken. Windings 606 and 608 are formed of multiple 24 gauge wires in parallel preferably within a common insulative sleeve. The effective diameter of winding 606 wire is approximately twice that of winding 608, e.g. 15 gauge and 18 gauge wire, respectively. The respective coils of each phase of windings 602 and 604 include a predetermined number of turns corresponding to the voltage output associated with that particular coil. The cumulative turns of coils 606 and 608 provide a second low- voltage, high-current output, e.g., 24-volts. For example, in the preferred embodiment, 12-volt coil 606 includes 5 turns, 24- volt coil 608 includes an additional 4 turns (for an effective total of 9) and high-voltage (e.g. 115 watts) coil 602 includes a total of 29 turns in each phase. In physical assembly, the respective coils corresponding to the high-voltage, and first and second low-voltages of each phase (and the control winding in the first phase) are grouped together as a unit and concurrently wound about a laminate core together, as a unit. In this manner, the respective coils are wound in close proximity, in thermal contact in effect, sharing the same space. This arrangement is particularly advantageous in a number of respects: a single stator generates a plurality of voltages; maximum wattage output can be obtained from any of the coils; and, the coils not in use operate as a heat sink for the working winding. The close proximity of the respective coils effectively makes the entire mass of the skein available to dissipate d e heat generated by the working winding. Rotor 220 is mounted on engine shaft 200 in coaxial disposition with stator 210, separated from stator 210 by a relatively small predetermined air gap 242, e.g. in the range of .020 to .060 inch, and preferably .030 inch. Specifically, engine shaft 200 is received in a central axial bore in rotor 220. A key 402 (FIGURE 4) ensures a positive rotation of stator 220 with shaft 200. A spacer 404 is disposed on shaft 200 to axially align rotor 220 with stator 210. Rotor 220 is preferably a permanent magnet rotor, of sufficiently light weight that it can be maintained in axial alignment with, and rotated in close proximity to stator 210, (i.e. with air gap 242 of less than approximately .060 inch), without the necessity of any bearings in addition to those conventionally included within engine 12. Rotor 220 suitably manifests a generator output power to rotor weight ratio in watts per pound of in excess of 150 or 200, preferably in excess of 500, more preferably in excess of 700, and most preferably in excess of 800. The preferred embodiment manifests in manifests a generator ouφut power to rotor weight ratio in the range of 800 to 900 in watts per pound. For example, for a 2-kilowatt unit, rotor 220 would suitably weigh no more than approximately 2.40 pounds. Similarly, for a 900-watt unit rotor 220 preferably weighs no more than 1.06 pounds. As will be more fully discussed in conjunction with FIGURE 8, in the preferred embodiment, this is achieved economically by employing high energy product magnets, and consequence poles. Fan extension 230, disposed in axial alignment with shaft 200, is employed to couple fan 240 to shaft 200. Extension 230 suitably comprises a generally cylindrical body 231, with respective reduced diameter ends 232 and 234 (best seen in FIGURE 2), and includes a centrally- disposed axial bore 236. Reduced-diameter end 232 is received within the central bore of rotor 220 with the step to body 231 abutting the front surface of rotor 220. Fan 240 is mounted for rotation with shaft 200, to generate air movement to cool the various elements of generator unit 14, and particularly, stator 210 and electronic-controlled circuitry 250. Fan 240 suitably includes a plurality of blades, e.g. 5, mounted about a hub 408. Hub 408 suitably includes a central bore 410 generally conforming in cross-section to end 236 of extension 230, e.g. includes a flat 412 corresponding to flat 406. Fan 240 is mounted on extension 230 for rotation with shafts 200; fan 240 is suitably formed of a relatively lightweight plastic such as, for example, Celcon. End 234 of extension 230 is received within central bore 410 of fan 240. Extension end flat 406 cooperates with flat 412 in bore 410 to ensure positive rotation of fan 240 with shaft 230. Rotor 220, extension 230, and fan 240 are secured as a unit to engine shaft 200 by bolt 414, and a tensioning mechanism such as a washer 416 and a split washer 418. Bolt 414 is journaled through washers 416 and 418, and through the central bore of fan shaft extension 230, and threadedly engages an axial bore 420 in die end of engine shaft 200. The tensioning mechanism tends to prevent bolt 414 from disengaging with shaft 200. Housing 260 and a top plate 282 cooperate to enclose stator 210, rotor 220, fan 240 and control circuit 250. Top plate 282 extends perpendicularly from frame upright 164, suitably affixed to upright 164 by, e.g., bolts, rivets or welding. Housing 260 is suitably affixed, e.g., bolted, to top 282, and frame 16. As will hereinafter be more fully discussed, housing 260 is formed of a relatively lightweight thermally and electrically conductive material and is suitably employed as an electrical ground for circuitry 250, as well as a thermal heat sink to facilitate cooling. Referring now to FIGURES 3, 4 and 5, housing 260, top 282 and frame upright 164 cooperate to, in effect, define a closed structure with pre-defined apertures (e.g. grills) in predetermined positions to define an airflow path to facilitate cooling of the elements of generator 14* Specifically, a grill 320 (best seen in FIGURES 3 and 4) is formed in frame upright 164. Housing 260 includes a face 422 and respective sides 424 and 426 (best seen in FIGURES 4 and 5) and a bottom 428. A first grill 430 and second smaller series of apertures 432 are formed at predetermined positions through face 422. Additional sets of apertures 434 and 436 are suitably formed through side wall 424 and, if desired, apertures 436A are formed through side wall 426. Grill 430 is disposed in a general alignment with fan 240. In operation, fan 240 draws air into the enclosure through grill 430, creating a positive pressure in the interior of the enclosure, and forcing air to exit through grill 320 in upright 164 and apertures 432, 434, 436 and 436A. Apertures 432, 434, and 436 are strategically placed to cause airflow over specific heat-sensitive components. Additionally, the action of fan 240 itself causes an airflow in a radial direction off of the tips of fan 240. Particularly heat sensitive components are preferably disposed in the radial airflow generated by fan 240, e.g., a heat sink 500 for heat-sensitive electronic components is disposed radially offset from, but axially aligned. Heat sink 500 can be of various shapes and dispositions (see FIGURE 5A). The use of a fan directly coupled to motor shaft 200 is particularly advantageous in that airflow varies as a function of need. The higher the rpm of the engine, the more power is generated, and concomitantly, more heat is generated by the components. However, as the engine rpm increases, the airflow generated by fan 240 also increases to accommodate the additional heat generated. Control circuitry 250 rectifies the signals from the stator coils. Control circuitry 250 may comprise any suitable rectification circuits to convert the signals from stator 210 to appropriate DC signals. Referring to FIGURES 5, and 5 A, control circuitry 250 suitably comprises a first full wave bridge rectifier 706 (high-voltage, low-current) cooperating with a heat sink 500 (500A in FIGURE 5A); a fuse 501; a suitable switch 704; and a second rectifier 700 (high voltage, low current). Control circuitry 250 suitably cooperates with a suitable conventional duplex receptacle (outlet) 702; three-pole double throw switch 704, and positive and negative post terminals 703 and 705. The components of control circuitry 250 and cooperating elements can be variously disposed within housing 250. Alternative dispositions are shown in FIGURES 5 and 5A. Referring to FIGURE 5A, rectifier 706 and fuse 501 may suitably be disposed on face 422. Rectifier 706 suitably comprises a diode bridge with the diodes sized to withstand a short-circuit output greater than that capable of being produced within the power limitations of engine 12. Fuse 501 protects the diodes of rectifier 706 from a reverse polarity connection at terminals 703 and 705, during, e.g. a battery charging operation. Outlet 702 and terminal posts 703 and 705 suitably extend through, and switch 704 mounted on sidewall 424. Terminals 703 and 705, can, however, be disposed elsewhere on housing 260, as desired, to accommodate the particular configuration and disposition of components employed in control circuit 250. For example, while positive terminal 703 is shown at the top of wall 424 in FIGURE 5A, and negative terminal 705 shown lower in the wall, relative positions can be reversed (see FIGURES 1 and 5). Rectifier 700 can be mounted on sidewall 424, or, if desired, can be formed as a separate assembly mounted on the back of outlet 702. As will be hereinafter be discussed, positive terminal 703 is electrically isolated from wall 424 by suitable insulative washers 504. Negative terminal 705 is electrically (and mechanically) connected to side wall 424. As will be discussed, housing 260 serves as both electrical ground and heat sink to various elements of circuit 250. Referring now to FIGURE 7A, high- voltage low-current winding 602 is suitably connected to 3-phase bridge 700. The ouφut of rectifier 700 is connected to duplex receptacle 702. The respective low-voltage, high-current ouφuts of winding 604, i.e. from windings 606 and 608, are applied to the respective throw terminals of 3-pole double throw switch 704. The poles of switch 614 are connected to control circuit 250 (rectifier 706; FIGURE 5A), which provide low-voltage, high-current ouφut at terminals 703 and 705. In operation, engine 12 rotates shaft 200, and rotor 220 and fan 240 rotate concomitantly. Rotation of rotor 220 causes current to be induced in the coils of the stator 210. The respective ouφuts of stator 210 are selectively applied to control circuit 250, which suitably rectifies the signals to provide the desired low-voltage, high-amperage ouφut signals at positive and negative ouφut terminals 703 and 705 for uses such as charging batteries, and high- voltage, low-current at duplex receptacle 702 for powering conventional power tools, lights, and the like. FIGURES 7A and 7B, control circuitry 250 may also comprise, if desired, various circuits to provide certain protection functions, in addition to, or in lieu of fuse 501. The protection circuits are advantageously disposed on a printed circuit board 250A (FIGURE 5). With specific reference to FIGURES 7B and 7C, in such control circuit rectifier 706 is preferably SCR- controlled, i.e., comprises a positive diode block 708, and a negative diode block 710 formed of silicon-controlled rectifiers (SCR's) cooperating with a suitable control circuit 712. Control circuit 712, in turn, cooperates with respective sensing circuits such as, for example, a reverse-polarity sensor 714, and enable and disable sensors 716 and 718. Reverse polarity sensor 714 suitably disables control circuitry 712 (and hence rectifier 706) if it senses a reverse polarity voltage in excess of a pre-determined level, i.e., in excess of 0.6 negative volt across ouφut terminals 703 and 705. Thus, the unit is disabled if, e.g. leads from terminals 703 and 705 are coupled to wrong polarity battery terminals during a charging operation. Enable sensor 716 and disable sensor 718 sense the voltage across ouφut terminals 703 and 705, e.g., from a battery, and enables control circuit 712 only if a voltage in excess of a pre¬ determined threshold, e.g., 150 millivolts. In this manner, the unit is disabled if the ouφut terminals are disconnected from a battery, to avoid sparks or short-circuits across inadvertent connections. If desired, a momentary switch SI can be provided to override the protection features for the purpose of supplying power to a battery that is completely without charge or supplying power to a load with no battery. Referring now to FIGURE 7C, the negative block of rectifier 706 suitably comprises 3 SCR's receptive of control signals from control circuit 712. Control circuit 712 selectively enables SCR's 704 to permit current to flow to the negative pole of the circuitry. Control circuit 706 suitably comprises respective transistors Ql and Q4, respective resistors R2 and R3, and a momentary contact switch SI. Transistor Q4 is selectively forward biased by the sensing circuitry, as will be explained. In the absence of a sensed reverse polarity, when transistor Q4 is forward biased, Ql is turned on through divider chain resistors R2 and R3, enabling SCR's 704. Reverse polarity sensor 714 disables control circuit 712 upon sensing a reverse polarity connection at ouφut terminals 703 and 705. In the preferred embodiment, reverse polarity sensor 714 comprises respective resistors R4, R5, R6 and Rll, a diode CR7, and respective transistors Q2 and Q3. A relatively small reverse polarity voltage across terminals 703 and 705, e.g., by virtue of a reverse polarity connection to a battery to be charged, causes diode CR7 to be forward biased. When diode CR7 is forward biased in excess of a predetermined level, e.g., 600 millivolts, a base drive is provided across divider chain R5 and R6, turning on transistor Q3. Transistor Q3 is collector coupled to the base of transistor Q2. When transistor Q3 is turned on, it disables transistor Q2 and, concomitantly, transistor Ql in control circuit 712 to disable rectifier 706. Enable sensor 716, in effect, enables control circuit 712 only after terminals 703 and 705 are connected to a battery, to avoid sparking or inadvertent short circuits. Enable sensor 716 suitably comprises a capacitor C2, respective resistors Rl, R10 and R16, a diode CR5, and a Zener diode CR4. When diode CR5 is forward biased above predetermined threshold, e.g., 600 millivolts, the voltage is applied to the cathode of Zener diode CR4. When the voltage overcomes the Zener voltage of the diode, voltage is then applied across a voltage divider comprising resistor R10, and resistor R9 in control circuit 712, to provide a bias voltage for transistor Q4 in control circuit 712. This, in turn enables transistor Ql and, hence, rectifier 706. Should die voltage at terminal 703 drop below 600 millivolts, as would be in me case of a short circuit, transistor Q4 is turned off, turning off transistor Ql, and disabling SCRs CR1, CR2 and CR3 of rectifier 706. Resistor Rl and Capacitor C2 comprise a filter for noise immunity. Disable sensor (over-voltage sensor) 718 senses a rise in voltage when current flow drops and responsively disables rectifier 706. This effectively disables the high current ouφut when terminals 703 and 705 are disconnected. Disable sensor 718 comprises respective Zener diodes Zl and Z2, capacitor Cl, resistors R7 and R12, and transistor Q5. Zener diode Z2 is selectively switched in and out of the circuit depending upon which of the respective low-voltage, high-current windings has been selected, e.g., the 12- or 24-volts. When voltage is applied across diode CR5 to the cathode of Zener diode Zl or Z2, the Zener voltages, e.g., 22 volts for Zener Z2 and 18 volts for Zener Zl , is applied across the divider comprising resistors R7 and R12, turning on transistor Q5. This, in turn, disables transistor Q4 and control circuit 712, disabling SCR block 710. In accordance with another aspect of the present invention, to facilitate a light weight unit, housing 280 serves as both an electrical ground and as a heat sink for various of the circuit components. Referring now to FIGURES 7B, 7C, 4, and 5, the anodes of SCR's 704 of block 710 are connected directly to housing 260. Specifically, the anodes of SCR's 704 are electrically and thermally connected to housing 260, e.g., to wall 422. Negative terminal 705 is electrically and mechanically connected to housing 260, i.e. wall 424 of housing 260, and thus electrically connected through the housing to the anodes of SCR's 704. Terminal 705 suitably includes a post extending through wall 424 (Fig 1 and 4). Housing 260 ώus serves both as electrical ground and heat sink. The cathodes of positive diodes in block 708 are electrically and thermally connected to heat sink 500 (500A in FIGURE 5A) and therefrom to terminal 703. The post of terminal 703 extends through an aperture 502 in wall 424 of housing 260, electrically isolated by insulative washers 504. By employing housing 260 as both electrical ground and a heat sink, the necessity of a separate heat sink for one set of diodes is avoided. As previously noted, rotor 220 is preferably a permanent magnet rotor of a sufficiently light weight that it can be maintained in axially alignment with, and rotated relative to, stator 210 without the necessity of any bearings in addition to those conventionally included within engine 12. In the preferred embodiment, this is achieved by employing high energy product magnets, and consequence poles. Referring to FIGURES 8, 8A, 8B, and 8C, rotor 220 preferably comprises a generally disc-shaped core 800 bearing a polarity of high energy product Magnets 802 to dispose on the circumferential surface thereof. Magnets 802 are preferably disposed within the insets 803 in the circumferential surface, with the intervening portions of core 800 comprising consequence poles 802. Magnets 802 include an outer face 808, and an inner face 810. (810A in FIGURE 8A) Magnets 802 is disposed within inset 803 with inner surface 810 (in 810A) seated on a conforming surface 805 (805A) of core 800, offset from the adjacent consequence poles 806 by a pre- determined gap 812. Magnets 802 preferably comprise high energy product magnets having a flux density of at least on the order of five kilogauss, suitably formed of a rare earth alloy such as neodymium iron boron, or samarium cobalt. Such rare earth materials tend to be extremely expensive, and, accordingly, it is desirable to minimize the amount of material used. However, at the same time, it is desirable to generate relatively high flux densities. In the preferred embodiment, magnets 802 are relatively thin, e.g. on the order of 1/10 of an inch thick, but present a relatively large area, e.g. 3/4 of an inch by approximately one inch, to minimize the amount of high energy product magnet used. In accordance with one aspect of the present invention, the overall size of the device, and amount of high energy product magnetic material used, is minimized for a given total flux. Specifically, the area of magnet face 808 is greater than the area of the face 806 of consequence poles by approximately the ratio of the flux density produced by the permanent magnet to the allowed flux density of the consequence pole. Thus, by maximizing the area of the permanent magnet relative to the consequence pole, a smaller diameter core is required for a given total flux. A smaller diameter core results in less weight and less magnetic material being required for a given total flux. Inner faces 810 (FIGURE 8C) and corresponding inset surface 805 of inset 803 are preferably curved along a radius concentric with magnet outer surfaces 808 and the outer surfaces of consequence poles 806. Respective gaps 812 are maintained between each magnet 802 and adjacent consequence pole 806. Gap 812 is preferably significantly larger than air gap 242 (FIGURE 2) between rotor and stator, e.g., five or six times greater, to ensure that the majority of magnetic energy is directed into the stator rather than across gap 812. Magnets 802 are suitably secured to core 800 with glue. If desired, rotor 220 can be wrapped in a non-metallic material, e.g. fiberglass tape, to secure magnets 802 against centrifugal forces generated by rotation. Magnet inner face 810, 810A and corresponding inset surface 805 and 805A may be any configuration, so long as they conform to each other. For example, referring to FIGURE 8D, inner face 810A of magnet 802 and mating surface 805 A on core 800, may be planar. In such case, it has been determined that it is desirable to include a notch 814, extending radially below surface 805(a) in the vicinity of magnet consequence pole air gaps 812. Notch 814 has been found to increase the amount of flux directed into the stator from rotor 220. If desired, generator unit 14 can be modified to generate AC signals. Referring to FIGURE 9, a 115 volt AC signal can be provided by: replacing high voltage low current winding 602 with a higher voltage winding 902, e.g. 150 volt winding; replacing three-phase bridge 700 with an analogous circuit 904 rated for the higher voltage; and applying d e DC signal to a suitable inverter 906. Three-phase regulator 904 generates an ouφut voltage on DC rail 905A, 905B at a level, e.g., 150 volts DC, sufficient to generate the desired AC voltage. DC rail 905A, 905B is suitably floating with respect to system ground (i.e. housing 260), to facilitate grounding inverter 906 in accordance with UL standards. Inverter 906 generates an ouφut signal 915 at outlet 702 that simulates a sine wave of predetermined frequency. Inverter 906 is preferably a variable frequency inverter, and suitably includes a control section 908 and power conversion section 910. In general, control section 908 generates switching control signals to power conversion section 910, which responsively applies the DC rail voltage to the respective terminals (LI, L2) of outlet 702. The application of the DC rail signals generates an ouφut signal 915 with a predetermined waveform simulating (e.g. having the same RMS value as) the desired AC signal (e.g 120v 60 Hz in the U.S.; v 50 Hz in Europe). Stable supply voltages ( e.g. 15v, 5v) for inverter control section 910 are suitably derived from control winding 605 by a bridge rectifier 912 and regulator 914. The use of a variable frequency inverter is particularly advantageous in a number of respects. Since the AC signal is developed syndietically by inverter 906, it is independent of the φm of engine 12. Accordingly, inverter 906 can be adjusted to provide full power at various predetermined frequencies, e.g., 60 Hertz in the United States, and 50 Hertz in most European countries. Further, by varying the frequency of the ouφut as a function of load current draw to accommodate extraordinary transient demands from loads, unit 10 is made capable of operating with much larger devices man would typically be the case. Particularly, it has been determined diat the current required to start a large motor, such as, for example, the refrigeration compressor on an air conditioner, is much greater man the current required to maintain operation of the motor once it has been started. When the load, e.g. motor, draws a current higher than the rated ouφut of the system, me DC rail voltage applied to inverter 906 tends to drop. It has been determined that by reducing the frequency of e AC ouφut signal as a function of, e.g. proportionately with, the reduction in voltage, unit 10 can be used to start, and maintain in operation, motors that would typically require a much larger generator. Lowering the frequency at the applied signal effectively lowers the operating RPM of the motor, e.g. compressor, to be started. This lowers die load on d e motor and therefore decreases me current required to start the motor. The frequency can men be increased, increasing die motor RPM to the designed operating speed. For example, when die voltage drops below a pre-determined level, e.g. approximately 110 volts, frequency is decreased, preferably linearly tracking voltage down to about 30 hertz and 50 volts. Once the motor is running, the current drawn by die motor reduces, the DC rail voltage rises, and die normal operating frequency is resumed. For example, 2 kilowatt generator in accordance with me present invention is capable of starting and maintaining a 13,000 btu air conditioner which, previously, in order to accommodate die starting loads, required a 4 or 5 kilowatt generator. Conversely, since d e speed of engine 12 can be lowered wid out reducing frequency, die speed of engine 12 can be varied as a function of ouφut drawn. Thus if only a fraction of the system capacity is being drawn, the engine can be throttled back or made to idle. More specifically, a voltage feedback control can be employed to govern the speed of the engine. The speed of die engine is thus varied as a function of load, providing decreased noise and increased fuel economy. As previously noted, regulator 904 generates the DC rail signal to inverter 906. Referring to FIGURE 10, a suitable regulator 904 comprises: a rectifier bridge 1002; a leveling capacitor C21; a comparator 1004; and an optoisolator 1006. Rectifier bridge 1002 is suitably formed of respective diodes D28, D29 and D30 and respective SCR's TH1 , TH2, and TH3. Comparator 1004 suitably comprises respective transistors Q13 and Q15, and a voltage divider formed of resistors R21 and R23. The ouφut leads (J6, J7, and J8) from 3-phase alternator coil 902 provide 3-phase input signals to bridge 1002. Such alternator ouφut signals are of variable voltage and frequency in accordance widi the RPM of the engine. Comparator 1004 selectively activates opto-isolator 1006, to turn on SCR's TH1, TH2, and TH3 to generate a regulated ouφut across DC rails 905A and 905B. In essence, comparator 1004 provides active feedback to maintain the rail voltage at the predetermined level, e.g., 150 volts. Indicia of the rail voltage is derived, and compared against a reference voltage (a stable regulated DC voltage provided by regulator 914). When the rail drops below the designated voltage, e.g., 150 volts, comparator 1004 activates opto-isolator 1006 to turn on SCRs TH1-TH3. Stable supply voltages ( e.g. 15v, 5v) are suitably derived from control winding 605 by bridge rectifier 912 and regulator 914. Bridge 912 suitably comprises a conventional single phase diode bridge. Regulator 914 suitably comprises respective conventional regular devices Vrl and Vr2, such as Motorola 78LXX series pass three lead regulator devices to provide stable, regulated DC ouφuts at appropriate levels ( e.g Vrl 15v, Vr2 5v) for inverter control 908 (15v), SCR's TH1, TH2, and TH3 (5v), and for deriving a stable reference signal for comparator 1004 (5v). As previously noted, control section 908 generates switching control signals to power conversion section 910. Referring to FIGURE 11 , inverter control section 908 suitably comprises: a suitable microcomputer 1102; a suitable digital-to-analog ("D to A") converter 1104; a suitable crystal 1106 of predetermined resonant frequency, e.g. 4 megahertz; suitable feedback signal interface circuits 1108 and 1115; and suitable combinatorial logic 1110. Microcomputer 1102 is suitably a conventional microcomputer, such as, for example, a Ziolog Z86E04, including internal random access memory (RAM), counters and registers ( which can be implemented in the RAM in accordance with standard techniques), and additionally, respective internal comparators capable of generating interrupts, and respective port registers for controlling die ouφut signals at various ouφut terminals (pin) with the microcomputer. (For convenience of reference, corresponding port registers will sometimes be referred to synonymously.) More particularly, microcomputer 1102 suitably includes two internal comparators, the first comparing the voltage applied at pin 8 to that applied at pin 10, and the second comparing d e voltage applied at pin 9 to the voltage applied at pin 10 (die voltage at pin 10 is a common reference signal). As will be explained, the common reference signal is suitably a controlled ramp voltage generated by D to A converter 1104. Microcomputer 1102 generates a count (AtoD, FIGURE 11 A) which is reflected at pins 1-4 and 15-18. D to A converter 1104, suitably an R2R resistor ladder connected to pins 1-4 and 15-18 of microcomputer 1102, generates a ramp reference signal reflecting that count. The voltage across d e R2R ladder is filtered and applied as die common comparator reference signal at microcomputer pin 10. As will be described, comparisons of various parameters, (e.g. indicia of ouφut signal 915 voltage (pin 8), indicia of supply voltage or overcurrent condition (pin 9)) against die ramp signal are employed to generate digital indicia of the parameters or specified functions; the instantaneous value of count AtoD when die parameter and reference voltage are equal is indicative of die value of die parameter voltage. The comparisons are also employed to selectively initiate interrupt functions. Microcomputer 1102 is suitably interrupt driven; various interrupt signals are generated to effect predetermined functions. For example, interrupts are generated in response to: a comparison of die D to A ramp reference signal to the indicia of ouφut signal 915 from interface 1108 (switching cycle frequency adjustments); a comparison of the D to A ramp reference signal to the indicia of ouφut current, current sense signal (ISEN) (overcurent protection) and indicia of die supply voltage (below power transistor gate threshold protection); and a comparison of counts from an internal clock to respective control parameters (pulsewidth of switching pulses generated at pins 12 and 13 and deadtime between pulses). In addition, microcomputer 1102 suitably cooperates with combinatorial logic 1110 to generate respective switching signals LHRL (Left High, Right Low) and RHLL (Right High, Left Low) to power conversion section 910, in response to which power conversion section 910 effects controlled application of the DC rail to ouφut terminals LI and L2. More specifically, microcomputer 1102 generates, at pins 12 and 13, respective alternative pulses of controlled pulsewidth, relative timing, and repetition rate. These pulses are gated widi current sense (ISEN) feedback signal, to generate switching signals LHRL and RHLL. Microcomputer 1102 and combinatorial logic 1110, may also generate, if desired, further switching signals HIV (BOOST) and CHARGE, and GOV to power conversion section 910 to effect advantageous shaping of ouφut signal 915. The operation of microcomputer 1102 will be more fully described in conjunction with Figures 11A - 11F. Indicia of die voltage of ouφut signal 915, suitable for comparison to the ramp reference signal generated by A to D converter 1104, is provided by feedback signal interface circuit 1108. Feedback signal interface circuit 1108 suitably comprises: a single phase diode bridge 1112 connected to output terminals LI and L2; a suitable low pass filter circuit 1114 (e.g., resistors R29 and R30, and capacitor C7); a Zener diode Zl; and second low pass filter circuit 1116 (e.g., resistors R8 and R14, and capacitor C18). Ouφut signal 915, as provided at ouφut terminals LI and L2 is applied to bridge 1112, to generate an average DC signal. The DC signal is filtered, smoothed and limited by filters 1114 and 1116, and Zener diode Zl, and applied to a voltage divider (R8, R14) to generate a signal proportional to the average voltage of ouφut 915. The signal is applied at pin 8 of micro-computer 1102, for comparison against the reference ramp. Signals indicative of under direshold voltage supply levels and over current conditions are provided by second feedback interface circuit 1115. More specifically, the 15 volt supply voltage generated by regulator VRl of supply of 914 is applied across a voltage divider formed of Zener diode Z5 and resistor R26 to generate a signal indicative of die supply voltage level. This signal is applied to pin 9 of microcomputer 1102 for comparison against the reference ramp. In addition, a signal (ISEN) indicative of the current level of the ouφut signal generated by power converter 910 is applied through an isolation diode Dl to 1009 of microcomputer 1102. In essence, if the supply voltage level drops below a pre-determined minimum, or the ouφut current exceeds a pre¬ determined maximum, an interrupt is generated to disable power converter 910, and protect its components from damage. Power conversion section 910, in response to switching control signals LHRL and RHLL, (and further switching signals HIV (BOOST) and CHARGE, if utilized) from control section 908, selectively applies the DC rail voltage to the respective terminals (LI, L2) of outlet 702 to generates an ouφut signal 915 with a predetermined waveform. Referring to Figure 12, a suitable basic power conversion circuit 910A comprises: respective high-side isolated power switch circuits 1202 and 1204; respective low-side non-isolated power switch circuits 1206 and 1208; and a current sensor amplifier 1210. High-side isolated power switch circuits 1202 and 1204 and low-side non-isolated power switch circuits 1206 and 1208 each include a power transistor (Ql, Q2, Q3, and Q4, respectively) and a suitable firing circuit for turning the power transistor on and off in accordance with switching signals LHRL and RHLL. Power switch circuits 1202-1208 are interconnected in an H- configuration: High-side isolated power switch circuits 1202 and 1204 define controlled current paths to ouφut terminals LI and L2, respectively, electrically connected together at a high-side terminal 1203 (e.g. the drains of power transistors Ql and Q2 are connected at terminal 1203); and low-side non-isolated power switch circuits 1206 and 1208 define controlled current padis to ouφut terminals LI and L2, respectively, electrically connected together at a low-side terminal 1207 (e.g. the sources of power transistors Q3 and Q4 are connected at terminal 1207). In the basic configuration of Figure 12, high-side terminal 1203 is connected to positive rail 905A and low-side terminal 1207 is connected, through an isolation diode D7, to negative rail 905B. Power switch circuits 1202-1208 effectively operate as an electronically controlled double pole, double pole switch, selectively connecting the DC rail to terminals LI and L2 in response to switching control signals LHRL and RHLL. More specifically, switching signal LHRL is applied to high-side isolated driver 1202 and low-side non-isolated driver 1208, and switching signal RHLL is applied to high-side isolated driver 1204 and low-side non-isolated driver 1206. When LHRL is of a predetermined state, (e.g. low), high side terminal LI is connected to positive DC rail 905 A by driver 1202, and low side terminal L2 is connected to negative DC rail 905B by driver 1208. Conversely, when RHLL is of a predetermined state, (e.g. low), high side terminal LI is connected to negative DC rail 905B by driver 1204, and low side terminal L2 is connected to positive DC rail 905A by driver 1206. By alternately generating switching signals LHRL and RHLL, a simulated sine wave, shown in Figure 13, can be produced, having an RMS value controlled by the period of time ("Dead Time") between turning off one pair of drivers ( time Tl) and the turning on of the opposing pair (time T2). Control of the dead time in relationship to the voltage levels provides an RMS value approximately equal to mat of the desired sine wave. It is desirable that the firing circuits of isolated drivers 1202 and 1204 quickly the associated power transistor Ql, Q2 into a saturated state when the associated switching signal LHRL, RHLL changes state to minimize power dissipation during die switching interval. A particularly economical firing circuit t at provides advantageous turn on and turn off characteristics comprises: a resistor R13 (R19); an NPN transistor Q9 (Q10); a diode D2 (D3); a capacitor C4 (C2); and respective resistor R9 (R15) and R6 (R10). If desired, respective capacitors C8 (CIO) and C6 (C9) may be connected between the drain and source and gate and source of power transistor Q 1 (Q2) to prevent any high frequency oscillations, and a Zener diode Z4 (Z7) connected between the drain and source of power transistor Ql (Q2) to limit the gate voltage to no more than a predetermined value, e.g. 15v. In the preferred embodiment control signals LHRL and RHLL are at a low level when actuated and a high level when nonactuated. When the associated control signal LHRL (RHLL) is nonactuated, i.e. high, transistor Q9 (Q10) is rendered conductive. This, in effect, grounds die gate of power transistor Ql (Q2) and renders it nonconductive. However, a current path is created from the 15 volt supply dirough diode D2 (D3) and resistor R6 (R10); approximately 15v is thus dropped across resistor R6 (R10). With transistor Q9 (Q10) conductive, capacitor C4 (C2) is effectively in parallel with resistor R6 (R10) and is therefore charged to a level (approximately 15v) somewhat in excess of the threshold gate voltage (e.g. 8v) necessary to place power transistor Ql (Q2) into saturation. When the associated control signal LHRL (RHLL) changes to an actuated state, i.e. goes low, transistor Q9 (Q10) is rendered nonconductive. This, in effect, places the gate of power transistor Ql (Q2) at 15v and renders it conductive. When power transistor Ql (Q2) is rendered conductive, d e device exhibits very little resistance, and die source voltage approaches the voltage of the drain (e.g., 150 volts) die negative terminal of capacitor C4 (C2) thus assumes a voltage approximating the rail voltage (150 volts). Since capacitor C4 (C2) is already charged to approximately 15 volts, the positive side of me capacitor is at a voltage approaching the rail voltage plus the charge voltage, i.e., 165 volts. This, in effect, reverse biases diode D2 (D3), rendering the diode non-conductive and effectively blocking the 15 volts ply. However, since capacitor C4 (C2) is charged to a level above the set saturation threshold gate voltage of power transistor Ql accordingly, transistor Ql continues to conduct. The level of the source voltage (15 volts) and die level to which capacitor C4 (C2) is initially charged, is chosen to initially place power transistor Ql (Q2) into a hard full conduction. However, once diode D2 is blocked, capacitor C2 begins to discharge through resistor R9 (R10). The time constant of capacitor C4 (C2) and resistor R9 (R10) is chosen such diat the charge on capacitor C4 (hence the gate voltage) approaches (is only slightly above) the threshold value of power transistor Ql (Q2) at the point in time when the associated control signal LHRL (RHLL) changes state. In those systems where the frequency varies, die time constant is chosen such that the gate voltage is approaching (slightly higher than) the threshold value at die lowest frequency at which die system is intended to operate. When d e associated control signal RHRL (RHLL)initially resumes a non-actuated state, i.e., goes high, transistor Q9 (Q10) is again rendered conductive, grounding d e gate of, and turning off, power transistor Ql (Q2) and die cycle is repeated. By discharging capacitor C4 (C9) to a point approaching the ireshold voltage (eliminating excess charge), the turn off speed of power transistor Ql (Q2) is increased. The feedback signal indicative of ouφut current level (ISEN) provided to feedback interface circuit 1115, is generated by current sensing amplifier 1210. Amplifier 1210 simply comprises a resister R3, and an amplifier comprising transistor Q13. Resister R3 develops a voltage indicative of die current through power transistors Q1-Q4 if die voltage across resister R3 exceeds a pre¬ determined limit, transistor Q13 is rendered conductive effectively pulling die ISEN signal to ground. As previously noted, d e ISEN signal is applied as a gating control to combinatorial logic 1110 (nand gates U7A, U7B, and U7C; FIGURE 11) effectively inhibiting those gates. In addition, it effectively pulls the voltage at 1009 to zero, effecting generation of an interrupt, as will be discussed. A closer approximation to a desired sine wave ouφut can be achieved by shaping the waveform of ouφut signal 915. This may be accomplished by generating an auxiliary signal and controUably applying it through the activated high side power transistor to the associated ouφut terminal. The resultant waveform is shown in Figure 14. An auxiliary (boost) signal can be generated in any number of ways. For example, the boost sinal can be generated by an auxiliary winding added in stator 210. Referring to Figures 14, 15, 15 A, and 16, an additional winding 903 may be wound on stator 210 concurrently with winding 902, in essentially the same space. Winding 903 cooperates with a conventional three- phase diode bridge 1502 to generate an intermediate positive rail 905C of predetermined voltage (e.g., 70v). To generate the simulated sign wave waveform of Figure 14, die active terminal (LI, L2) is effectively connected to intermediate positive rail 905c, and positive rail 905a, in sequence. The intermediate rail voltage can be alternative to the positive rail voltage provided by winding 902, or it can be additive. For example, referring to Figure 15, the intermediate positive rail and positive rail voltages can be independently developed, e.g., winding 903 generates d e intermediate rail voltage, and winding 902 generates the entirety of die positive rail voltage, substantially independently from winding 903. If desired, however, windings 903 and 902 can be utilized to cooperatively generate die desired voltage at positive rail 905a. Referring briefly to Figure 15 A, in such an arrangement winding 903 would include a predetermined number of windings corresponding to d e desired voltage and intermediate rail 905c, and diode bridge 1502 would be interposed between regulator 904 and negative rail 905B. A winding 902A, corresponding to winding 902, but including a predetermined number of turns corresponding to die difference between die desired voltage at intermediate rail 905c and the voltage, e.g., 150 volts, at positive rail 905a is provided. Referring to Figure 16, die intermediate voltage (70v) rail 905c is connected high side terminal 1203 of basic power converter 910A (i.e., to the drains of power transistors (FET's) Ql and Q2 in high side isolated power switches 1202 and 1204), dirough a suitable isolation diode D4. The high voltage (e.g. 150v) positive rail is selectively coupled to high side terminal 1203 of basic power conversion circuit 910A through a booster circuit 1600. Booster circuit 1600 is substantially identical to high side isolated power switching circuits 1202 and 1204, including an FET Q5, and an associated firing circuit. Booster circuit 1600, however, is responsive to control signal HIV (BOOST) from control section 908 (from NAND gate U7C in Figure 11, corresponding to die signal at pin 11 of microcomputer 1102). The drain of booster circuit FET Q5 is connected to high voltage positive rail 905 A. The source of the power transistor is connected dirough an isolation diode D3 to d e drains of die power transistors Ql and Q2 in high side power switching circuits 1202 and 1204. A reverse polarity flyback diode D6 may be provided if desired. The auxiliary (BOOST) voltage can also be generated without the addition of an auxiliary winding from, for example, die energy generated during die ouφut signal dead time. This is accomplished by, an in effect, storing the energy generated during the ouφut signal dead time (which otherwise would be wasted) in a capacitor, and controUably discharging d e capacitor to generate die booster pulse. Specifically, referring briefly to FIGURE 11 , a separate control signal (CHARGE) inverted from the H1N (BOOST) control signal, i.e., active during diose periods from the trailing edge of a booster pulse (T3) to the leading edge of die booster pulse in the next successive half-cycle. The CHARGE signal is applied to a controlled storage/discharge circuit 1710 which effects charging and discharging of a capacitor to generate die booster pulse. Circuit 1710 suitably comprises an ΝPΝ transistor Q16, an FET Q6 and a capacitor C19. The CHARGE control signal is applied to die base of transistor Q16. When the charge signal is activated (e.g., low), FET Q6 is rendered conductive, effectively connecting capacitor C19 to positive rail 905C. (The use of the dead time energy to generate die booster pulse permits a lower rail voltage to be employed.) When the HIV (BOOST) control signal is actuated and hence control signal CHARGE de-actuated, FET Q6 is rendered non-conductive, and capacitor C19 additively discharges to die high side terminal 1203 of basic power convenor 910A to provide die boost pulse. As previously mentioned, microcomputer 1102 generates a count (pins 1-4 and 15-18) from which the ramp reference signal is generated by D to A converter 1104 and generates switching pulses (pins 11-13) to combinatorial logic 1110 from which the switching control signals to power conversion section 910 are derived (to control application of die DC rail to ouφut terminals LI and L2 by power conversion section 910). The switching cycle frequency is adjusted in accordance widi a comparison of the indicia of ouφut signal 915 from interface 1108 (pin 8) to the reference ramp (pin 10); and die pulsewidth of switching pulses and deadtime between pulses) adjusted in accordance with a comparison of counts from an internal clock to respective control parameters. Power conversion is disabled in response to overcurrent or inadequate supply voltage conditions reflected at pin 9. More specifically, referring to FIGURES 11 and 11 A, microcomputer 1102 maintains a number of internal registers and counters: an analog to digital count (ATOD); respective internal timers, timer 1 and timer 2; a cycle COUNT (COUNT); respective registers (RVALU and GVALU) for storing indicia of die ouφut voltage, and gate voltage (supply voltage), respectively; a count indicative of a half cycle of d e ouφut frequency (CPS); a count indicative of die trailing edge (Tl on FIGURE 14) of die switching pulses (PWM) a count (BASE) indicative of die time base of e ouφut frequency; an FET ouφut enable flag (DUMMY); and a register (FETMASK) indicative of the switch pulse ouφut pattern desired at pins 11-13) interrupt enable register (INTO having a bit corresponding to each interrupt; and respective port register P0 and P2 corresponding to pins 11-13 and pins 1-4 and 15-18 respectively. In addition, where a stepped ouφut signal is employed, counts indicative of die leading edge (TB) of the step (FIRST) and trailing edge (T4) (SECND) of the step, steps are also defined. If desired, d e processor may also include an interrupt priority register to designate die relative priorities of die respective interrupt. Referring to FIGURES 11 and 11 A-l IF, microcomputer 1102 suitably effects a diese operations through a continuous primary loop (simple racetrack) program with a predetermined number, e.g., 4 of interrupt driven subprograms. The basic loop program implements the operation of D to A converter 1104. The various other functions are interrupt driven. Referring now to FIGURE 11B, when power is first applied to microcomputer 1102, die various timers, registers, and ports are initialized (step 11). After initialization, microcomputer 1102 suitably effects a continuous primary loop implementing the operation of D to A converter 1904, and generation of die reference ramp. D to A converter 1104 in effect, generates a controlled ramp voltage from 0 to 5 volts. More specifically, A to D count ATOD, is incremented (step 1912), and men tested to determine whedier a rollover has occurred; count ATOD suitably runs from zero to 256, , men rolls over to zero (step 1914). Assuming a rollover has not occurred, die ATOD count is loaded to die port P2 corresponding to pins 1-4 and 15-18 (connected to ATOD converter 1904) (step 1916), and ATOD is again incremented (step 1912 repeated). If a rollover occurs, die contents of interrupt enable register INIT is modified to enable respective interrupts (step 1918): Interrupt IRQ0 (the over-current/insufficient supply voltage interrupt and interrupt IRQ2 (die ouφut voltage interrupt). As will be explained, over-current interrupt IRQ0 and ouφut voltage interrupt IRQ2 are permitted to occur only once per ramp cycle to avoid spurious readings. The insufficient supply voltage level and over current protection function is initiated by interrupt IRQ0. IRQ0 is generated when die voltage at pin 9 (supply voltage/FET gate voltage and ISEN over current signal) is equal to the reference ramp. Except in over current conditions (when ISEN drives pin 9 to ground, i.e., 0 volts), the count is indicative of the supply voltage (e.g., nominally 15 volts) applied to the gates of FET's Q1-Q4 of power converter 910. Referring to FIGURE 11C, when interrupt IRQ0 is generated, die value of count ATOD is averaged with the contents of register GVALU, and die average loaded into register GVALU to maintain indicia of die running average of the supply voltage level (step 1920). A determination is then made as to whedier or not die GVALU is within legal limits, e.g., the supply voltage is at least equal to the minimum logic high voltage seen by the power transistor gates (step 1922). Depending upon whether or not the content of GVALU is within legal limits, die FET enable flag (DUMMY) is either cleared, to disable power converter 910 (step 1924) or set to enable power convenor 910 (step 1926). The content of interrupt enable register (INIT) is then adjusted to disable interrupt IRQO (Step 1928) and a return from the interrupt is effected (step 1930). (As previously noted, interrupt enable register INIT is set to re-enable interrupt IRQO at the beginning of the next ramp cycle (step 1918). A measurement of the average rectified ouφut voltage is effected in response to interrupt IRQ2, generated each time that the reference ramp exceeds d e indicia of ouφut voltage provided at pin of microcomputer 1102. Referring to FIGURE 1 ID, when interrupt IRQ2 is generated, die ATOD count-(ATOD) is added into register RVALU, and die sum divided by two, to generate in register RVALU, count indicative of die running average of the ouφut voltage (step 1932). The input enable register (INIT) is adjusted to disable IRQ2 for the remainder of die ramp cycle (step 1934); interrupt IRQ2 is re-enabled at die beginning of the next ramp cycle (step 1918). A return from the interrupt is then effected (step 1936). The state of the switching signals generated at pins 11-13 of microcomputer 1102 is controlled by varying the content of switch control ouφut register (FETMASK). The FET state is varied on a periodic basis in accordance wid the pre-determined frequency reflected by die contents of the first interval timer, timer 1. For example, for an ouφut frequency of 60 hertz, an interrupt IRQ4 is generated, e.g., every 8.2 milliseconds. Referring to FIGURE HE, when timers 1 interrupt, IRQ4, is generated, FET ouφut enable flag (DUMMY) is tested (step 1938). If die flag indicates that die FETs have been disabled, e.g., because of an over current or supply voltage deficiency condition, switch control ouφut register FETMASK is cleared, to turn off (disable) die FETs of power converter 910 (step 1940), and a return from interrupt is effected (step 1942). Assuming that the FETs are not disabled, die cycle COUNT (COUNT) is incremented (step 1944) then tested against respective parameters to determine, and set die appropriate state of the power convertor FETs. The cycle COUNT is initially tested against count PWM (step 1946) indicative of die trailing edge of die switch pulse (Tl in FIGURE 13). If die cycle COUNT has reached pulse widdi count PWM, FETs Q1-Q4 in power convertor 910 are turned off, e.g., die port register (PO corresponding to pins 11 through 13 is cleared) (step 1948). The cycle COUNT is Λen tested against count (CPS) indicative of one-half cycle of the ouφut signal frequency (step 1950). If die cycle COUNT has reached half-cycle COUNT CPS, the status of the respective pairs of FETs in power convertor 910, i.e., LHRL and RHLL, are reversed (die bits in switch control ouφut register FETMASK are complimented) (step 1952), and d e contents of FETMASK loaded into port register PO corresponding to pins 11 through 13 (step 1954). The cycle COUNT is then cleared (step 1956), and a return from interrupt effected (step 1958). If die cycle COUNT is less dian the half-cycle parameter CPS, a return from interrupt is effected (step 1958). If die system is employing the basic power convertor 910 FIGURE 12, and die cycle COUNT is found to be less than the pulse width parameter PWM, a return from interrupt is effected. If however, a closer simulation of die sine wave is intended, i.e., plural steps are provided in die ouφut signal such as illustrated in FIGURE 14, e.g., power conversion circuits of figure 16 or 17 are employed, die cycle COUNT is tested against the edges of die high voltage pulse to control generation of the switching signal at pin 11 from which the HIV (BOOST) and CHARGE control signals generated. Specifically, die cycle COUNT is initially tested against count SECND corresponding to die trailing SECND edge of die high voltage pulse (T4 in FIGURE 14) (step 1960) if die cycle COUNT is greater or equal to trailing edge count SECND, die corresponding booster circuit is effectively disabled, e.g., die bit in port register PO corresponding to pin 11 is cleared (step 1962) and a return from interrupt effected (step 1964). If the cycle COUNT is less dian trailing count SECND, die cycle COUNT is then tested against the count corresponding to the leading edge (T3 in FIGURE 14) of the high voltage pulse (step 1956). If the cycle COUNT (already determined to be less than at corresponding to trailing edge T4) is greater dian or equal to d e count (FIRST) corresponding to die leading edge of high voltage pulse, booster circuit 1600 is enabled, e.g., die bit in port register PO corresponding to pin 11 is set (step 1968) and a return from interrupt effected (step 1970). If the cycle COUNT is less dian the count corresponding to die leading edge of die booster pulse, a return from interrupt is effected (step 1972). Additional steps are employed in d e ouφut signal, intervening tests of the cycle COUNT against the trailing and leading edges of diose pulses would suitably be effected between the test against the first step pulse trailing edge (step 1960) and first step pulse leading edge (step 1966). The frequency, and od er parameters of the ouφut signal are adjusted in accordance widi d e measured values of ouφut voltage on a periodic basis, suitably every two cycles of the nominal ouφut frequency, e.g., 32.256 milliseconds, (approximately 32.32 milliseconds for 60 hertz). In essence, die frequency pulse widdi and dead time parameters (the time difference between trailing edge Tl and half-cycle point T2) are varied to accommodate transient heavy loads (i.e., motor start-up). In essence, if the ouφut voltage falls below a pre-determined minimum, the frequency is decreased and ouφut wave shape parameters adjusted to provide additional power to die load. Upon generation of periodic interrupt IRQ5, FET ouφut enable flag (DUMMY) is tested (step 1974). If the ouφut is not enabled, FETs turned off during (step 1975) and a return from interrupt effected. Assuming mat d e FET ouφut is enabled, the ouφut voltage indicia RVALU is tested against a pre-determined minimum value corresponding to die voltage determined to be unacceptably low, e.g., 108 volts AC (the UL low voltage figure). (Step 1976) if die ouφut voltage is less dian or equal to d e minimum voltage, it is assumed that the unit is encountering an extra-ordinary load, e.g., a compressor motor under start-up conditions. Accordingly, die frequency of the ouφut signal is incrementally decreased down to a pre-determined minimum value (e.g., 30 hertz), and ouφut waveform parameter varied accordingly to maximize current to the load. More specifically, a count indicative of the time base for the designated ouφut frequency (during initialization to a count (e.g., 4) corresponding to die desired ouφut frequency, e.g., 60 hertz), is incremented by one (step 1978) to effectively decrease die ouφut frequency. The frequency is checked against the pre-determined minimum value, (e.g. , 30 hertz) and assuming that the frequency is widiin the acceptable range, the pulse widdi and dead time are adjusted to reflect the change in frequency, e.g., are adjusted so that ratios are maintained (step 1982). For example, the count (FIRST) corresponding to die leading edge of die high voltage pulse is set equal to the adjusted BASE count; die count (SECND) corresponding to the trailing edge of the high voltage pulse is then set to five times the leading edge count (FIRST); the count in (PWM) corresponding to the trailing edge (Tl) of d e pedestal pulse is set equal to seven times the BASE count and, d e count (CPS) corresponding to the half-cycle is set equal to eight times the adjusted BASE count. After the ouφut wave form parameters are adjusted (step 1982), a return from interrupt is effected (step 1984). As noted above, minimum frequency (e.g., 30 hertz) is established. Accordingly, if implementing the BASE count would cause the frequency to drop below the minimum, the BASE count is reset to the count corresponding to diat minimum (step 1986) prior to effecting adjustment of the output wave form parameters (step 1982). Once the extra-ordinary load condition abates, i.e., the inertia of start-up is overcome, an increase in ouφut voltage will be manifested due to the change in ouφut frequency and waveshape. Abatement is assumed once d e measured value RVALU reaches a predetermined value (e.g., 122 volts). Accordingly, assuming at die measured value of ouφut voltage RVALU is greater than the minimum voltage (e.g., 108 volts) the measured ouφut voltage (RVALU) is tested against the pre-determined maximum voltage deemed to indicate recovery from the extra-ordinary load condition (e.g., 122 volts) (step 1988). The frequency is then increased on incremental basis until it is brought up to die desired ouφut frequency (e.g., 60 hertz). More specifically, if the measured ouφut value is greater than pre-determined minimum (e.g., 108 volts), and less dian d e pre-determined maximum (recovery) voltage, a return from interrupt (step 1984) is effected. (Adjust parameters step 1982 is effected, but since die BASE count is not adjusted, die values do not change.) If, however, die measured value is greater dian die pre-determined maximum (recovery) voltage (e.g., 122 volts), the frequency BASE count (BASE) is decremented (step 1990), effectively increasing die ouφut frequency. The frequency is then tested against die desired frequency, i.e., die BASE count is tested against a count corresponding to d e desired frequency (e.g., 60 hertz) (step 1992). Assuming that die frequency is within range, die ouφut wave form parameters are adjusted to account for d e change in frequency (step 1982) and a return from interrupt effected (step 1984). If decrementing causes the BASE count to correspond to a frequency greater dian a desired frequency, die BASE count is set to that corresponding to die desired frequency (step 1994) prior to effecting the adjusting parameters (step 1982). As previously noted, since the speed of engine 12 can be lowered widiout reducing frequency, engine 12 can be throttled back, or made to idle under circumstances where if only a fraction of the system capacity is being drawn. Referring briefly to FIGURE 11, microcomputer 1102 suitably generates at pin 15 a control signal for a load demand governor. When the signal at pin 15 is high, transistor Q12 is rendered conductive, actuating an electromagnetic governor cooperating with the dirottle of engine 12. Referring to FIGURES 18A and 18B dirottle control signal GOV is suitably generated, as a function of the average load ouφut voltage (e.g., RVALU). In steady state (FIGURE 18A), the engine is suitably throttled back. However, when the ouφut voltage decreases d e pre-determined value, die governor signal is generated to throttle-up, and increase die RPM of engine 12. A particularly advantageous load demand governor control comprises a cylindrical magnet 1800, magnetized through die length, suitably formed of Alnico, cooperating with a non-magnetic push rod 1802, for example, formed of nylon, and a winding 1801 wound around a suitable core, e.g., formed of cast nylon. Push rod 1802 cooperates with throttle lever arm 1803. A spring 1806 biases throttle arm 1803 into an idle position. When die signal at pin 15 is generated, and transistor Q12 rendered conductive, a current padi is formed through winding 1801 causing magnetic interaction widi cylindrical magnet 1800. The magnetic interaction between coil 1801 and magnet 1800, causes magnet 1800 to move forward (FIGURE 18B) against the bias of spring 1806, throttling up (increasing die RPM) of engine 12. The control signal generated at pin 15 of microcomputer 1102 is suitably pulse- widdi modulated. The wider die pulse widdi, the more power to coil 1801, and concomitantly, the greater the movement of magnet 18, push rod 1802, and dirottle arm 1803. If desired, a fly-back diode 1804 can be provided across coil 1801. In some instances, weight and size advantages can be obtained by employing an external rotor disposed to rotate around the perimeter of an internally disposed stator. Referring to FIGURES 19(a) and 19(b) an external rotor suitably 1100 comprises a cylindrical casing 1102 formed of soft magnetic material, having an internal cavity 1104. Alternating permanent magnets 802 and consequence poles 1106 are disposed in die interior side wall of casing 1102. If desired, respective fins (fan blades) 1108 can be formed on the exterior side walls of cup 1102, to facilitate cooling. Likewise, the top of cup 1102 is substantially open, including respective cross-arms 1110 and a central hub 1112 to provide for connection to motor shaft 200. If desired, cross arms 1110 can also be configured as fan blades, to facilitate cooling interior chamber 1104. A stator 1114 suitably comprising a laminate core 1116, and respective windings 1118. Windings 1118 are suitably die type previously described. Core 1116 includes a central axial dirough-bore. Stator 1114 is secured to engine 202 by a mount 1122. Mount 1122 includes a central axial stem, 1124, widi an internal bore 1126. In assembly, mount 1122 is bolted to engine 202 widi engine shaft 200 journaled through bore 1126. Bore 1126 is somewhat larger in diameter dian is motor shaft 200, so that motor shaft 200 can rotate freely therein. Stator 1114 is disposed on mount 1122, with stem 1124 received in central bore 1322 of stator 1114. Stem 1124 suitably effects an interference fit with bore 1322 although, adhesive can also be used, if desired. Rotor 1100 is disposed over stator 1114 and fastened to engine shaft 200. Stator 1114 is received within d e interior of cavity 1104. Hub 1112 includes a central bore 1128 disposed in registry with a threaded axial bore 1130 in motor shaft 200. A bolt 1302 is received dirough bore 1128 and engaged in threaded bore 1130 to fasten rotary 1100 to shaft 200 for rotation therewith. External rotor 1100 and internal stator 1114 provide for a particularly compact generator unit. In some instances, the entire assembly can be disposed in die fly-wheel and magneto area of a small engine, such that generator is provided widi no parent external components. In addition, die assembly can be incorporated into a pull cable starter. As shown in FIGURE 19(a), a pull cable assembly and suitably including a ratchet and overriding spring-type clutch and pulley 1328, is secured to, and in axial alignment with rotor 1100, over hub 1112. When me rope is pulled, and pulley rotated, concomitant rotation of rotor 1100 is effected. It will be understood diat while various of the conductors and connections are shown in die drawing as single lines, they are not so shown in a limiting sense, and may comprise plural connections or connectors as understood in die art. Similarly, various power connections and various control lines and the like various elements had been omitted from the drawing for the sake of clarity. Further, the above description is of preferred exemplary embodiments of the invention, and die invention is not limited to die specific forms shown. Modifications may be made in d e design and arrangement of die elements in the scope of the invention, as expressed in the claims.

Claims: In the Claims: 1. A machine comprising a stator and a rotor, die 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 d at relative motion of die rotor and stator causes magnetic flux from the magnets to interact with and induce current in ie stator winding, wherein die permanent magnets are high energy product magnets wid a predetermined surface area, and die 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, and die magnets are disposed widiin die 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. 2. The machine of claim 1 wherein die surface area of the permanent magnets proximate to the stator is greater an die surface area of the consequence poles proximate to the stator by the ratio of the flux density produced by die permanent magnet to the allowed flux density of die consequence pole. 3. The machine of claim 1 wherein the magnets have a flux density of at least on the order 5 kilogauss. 4. The machine of claim 1 wherein: die insets are symmetrically disposed in die rotor surface proximate to d e stator; the consequence poles are symmetrically disposed in die rotor surface proximate to the stator; the magnets are centrally disposed widiin die insets. 5. The machine of claim 1 wherein the distance separating the magnets from the consequence poles is greater than the distance separating die rotor surface from the stator. 6. The machine of claim 5 wherein the distance separating the magnets from the consequence poles is at least five times greater than the distance separating die rotor surface from the stator. 7. The machine of claim 1 further comprising an engine to rotate the rotor. 8. The machine of claim 1 wherein the stator is generally annular with a central aperture and the rotor is concentrically disposed for rotation widiin the aperture. 9. The machine of claim 1 wherein the rotor comprises a hollow cylinder with die magnets mounted on an internal surface of the cylinder, and die stator is concentrically disposed widiin die cylinder. 10. The machine of claim 9 wherein die stator includes a central aperture, and the rotor is adapted for mounting on a shaft journaled through the stator central aperture. 11. The machine of claim 1 wherein die stator includes a plurality of windings. 12. The machine of claim 1 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. 13. The machine of claim 1 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 ouφut; and a second 3-phase star winding, each phase of die second winding including a predetermined number of turns corresponding to a second predetermined voltage ouφut; the corresponding phases of the respective 3-phase windings grouped together as a unit and wound about die core such mat the corresponding phases of d e respective 3-phase windings coils are wound in continuous thermal contact with each other. 14. The machine of claim 13 wherein the first predetermined ouφut voltage is on the order of 110 volts, and die second predetermined ouφut voltage is on die order of 12 volts. 15. The machine of claim 13 wherein each phase of at least one winding includes a first portion defined by a tap to provide a diird predetermined voltage ouφut. 16. The machine of claim 15 further comprising: a switch, for selectively effecting a connection to one of the second or third predetermined voltage ouφuts: and a rectification circuit, receptive of signals from the switch for generating DC signals. 17. The machine of claim 15 wherein die first predetermined ouφut voltage is on die order of 110 volts, the second predetermined ouφut voltage is on die order of 24 volts, and die third predetermined ouφut voltage is on the order of 12 volts. 18. The machine of claim 1 further comprising a rectification circuit, responsive to signals from the stator winding, for generating DC signals. 19. The machine of claim 18 wherein the machine includes respective ouφut terminals; and means for disabling die rectification circuit in response to a reverse polarity voltage in excess of a pre-determined level, across die ouφut terminals. 20. The machine of claim 19 wherein the machine further includes: means for enabling the rectification circuit in response to voltage in excess of a pre¬ determined level, across die ouφut terminals. 21. The machine of claim 12 further comprising: 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. 22. The machine of claim 21 wherein: the second winding includes a first portion defined by a tap to provide a third predetermined voltage ouφut; and die machine further comprises. a switch, for selectively effecting a connection between the second rectification circuit and one of the second or third predetermined voltage ouφuts. 23. The machine of claim 18 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; at least one of the rectification circuit components being electrically and thermally connected to d e housing, such diat the housing serves as a heat sink for the components and electrical ground for the ratification circuit. 24. The machine of claim 18 wherein: the machine further includes a fan mounted for rotation with the rotor; said rotor, stator, rectification circuit, and fan are disposed widiin 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 d e apertures to cool the components. 25. The machine of claim 18 further comprising an invertor, responsive to the DC signal, for generating an AC signal. 26. The machine of claim 25 wherein the invertor comprises a variable frequency invertor, responsive to indicia of die current drawn from me invertor, for generating an AC signal having a frequency in accordance widi die current drawn. 27. The machine of claim 25 wherein the invertor comprises a variable frequency invertor, responsive to indicia of the DC voltage level, for generating an AC signal having a frequency in accordance widi die DC voltage. 28. The machine of claim 1 configured as a generator for generating a predetermined power ouφut, wherein the ratio of the power ouφut to me weight of the rotor is greater dian 150 watts per pound. 29. The machine of claim 1 configured as a generator for generating a predetermined power ouφut, wherein die ratio of die power ouφut to die weight of die rotor is greater than 200 watts per pound. 30. The machine of claim 1 configured as a generator for generating a predetermined power ouφut, wherein die ratio of the power ouφut to the weight of die rotor is greater man 500 watts per pound. 31. The machine of claim 1 configured as a generator for generating a predetermined power ouφut, wherein the ratio of die power ouφut to die weight d die rotor is greater dian 700 watts per pound. 32. The machine of claim 1 configured as a generator for generating a predetermined power ouφut, wherein die ratio of the power ouφut to die weight of the rotor is greater dian 800 watts per pound. 33. A generator for generating a predetermined power ouφut, comprising a rotor and a stator including a stator winding, wherein: the rotor comprises a body of soft-magnetic material with a plurality d permanent magnets in a surface disposed proximate to the stator, separated from die 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 die power ouφut to the weight of the rotor is greater dian 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 ouφut; and a second 3-phase star winding, each phase of die first winding including a predetermined number of turns corresponding to a second predetermined voltage ouφut; the corresponding phases of die respective 3-phase windings grouped together as a unit and wound about die core such diat die corresponding phases of the respective 3-phase windings are in continuous thermal contact with each other. 34. The generator of claim 33 wherein the first predetermined ouφut voltage is on the order of 110 volts, and die second predetermined ouφut voltage is on the order of 12 volts. 35. The generator of claim 33 wherein each phase of at least one winding includes a first portion defined By a tap to provide a third predetermined voltage ouφut. 36. The generator of claim 35 further comprising: a switch, for selectively effecting a connection to one of the second or diird predetermined voltage ouφuts; and a rectification circuit, receptive of signals from the switch for generating DC signals. 37. The generator of claim 35 wherein the first predetermined ouφut voltage is on the order of 110 volts, die second predetermined ouφut voltage is on the order of 24 volts, the diird predetermined ouφut voltage is on the order of 12 volts. 38. The generator of claim 33 further comprising a rectifier, responsive to the first predetermined voltage ouφut signal, and an invertor cooperating with die rectifier, for generating an AC signal. 39. The generator of claim 38 wherein the invertor comprises a variable frequency invertor, responsive to indicia d current drawn from the invertor, for generating an AC signal having a frequency in accordance with the current drawn. 40. The generator of claim 38 wherein the invertor comprises a variable frequency invertor, responsive to indicia of die rectifier ouφut signal, for generating an AC signal having a frequency in accordance with die voltage of the rectifier ouφut signal. 41. A generator for generating an AC signal to a load, the generator comprising: a stator including at least one winding, a rotor disposed relative to the stator such diat relative motion of the rotor and stator causes magnetic flux from die rotor to interact with and induce current in die stator winding, a rectifier circuit, responsive to current in die stator winding, for generating a DC signal; and a variable frequency invertor, responsive to die DC signal and a control signal indicative of current drawn by die load, for generating die AC signal, die frequency of die AC signal being selectively varied in accordance widi current drawn by die load. 42. The generator of claim 41 wherein the control signal indicative of current drawn by the load comprises indicia of the voltage level of the DC signal. 43. A generator 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 die 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 ouφut; and a second winding, including a predetermined number of turns corresponding to a second predetermined voltage ouφut; the respective windings being grouped together as a unit and wound about the core such diat die respective winding coils are wound in continuous close thermal contact with each other. 44. The generator of claim 43 wherein: the rotor comprises a body of soft-magnetic material with a plurality of permanent magnets in a surface disposed proximate to the stator. 45. The generator of claim 44 wherein the magnets are high energy product magnets. 46. The generator of claim 44 wherein: the magnets have a predetermined surface area; the magnets are mounted in insets formed in die 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; die magnets are disposed widiin the insets, separated from adjacent consequence poles by a predetermined distance; and die surface area of die magnets is proximate the stator greater dian die surface area of the consequence poles proximate the stator. 47. The generator of claim 44 wherein the surface area of die permanent magnets proximate die stator is greater than die surface area of the consequence poles proximate the stator by the ratio of the flux density produced by die permanent magnet to the allowed flux density of the consequence pole. 48. The generator of claim 47 wherein the magnets have a flux density of at least on die order 5 kilogauss. 49. The generator of claim 46 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; the magnets are centrally disposed widiin die insets. 50. The generator of claim 46 wherein the distance separating die magnets from the consequence poles is greater dian die distance separating the rotor surface from the stator. 51. The generator of claim 50 wherein the distance separating the magnets from the consequence poles is at least five times greater than the distance separating die rotor surface from the stator. 52. The generator of claim 43 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 ouφut; 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 ouφut; the corresponding phases of the respective 3-phase windings being grouped together as a unit and wound about die core such that die corresponding phases of die respective 3-phase windings are in thermal contact with each other. 53. The generator of claim 52 wherein the first predetermined ouφut voltage is on die order of 110 volts, and the second predetermined ouφut voltage is on die order of 12 volts. 54. The generator of claim 52 wherein each phase of at least one winding includes a first portion defined by a tap to provide a diird predetermined voltage ouφut. 55. The generator of claim 54 further comprising: a switch, for selectively effecting a connection to one of the second or diird predetermined voltage outputs; and a rectification circuit, receptive of signals from the switch for generating DC signals. 56. The generator of claim 54 wherein the first predetermined ouφut voltage is on the order of 110 volts, die second predetermined ouφut voltage is on the order of 24 volts, the diird predetermined ouφut voltage is on the order of 12 volts. 57. A generator comprising a stator and a rotor, the stator including at least one winding, and die 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, improved wherein: the rotor comprises a hollow cylinder widi die magnets mounted on die internal surface of the cylinder; the stator is concentrically disposed widiin the cylinder; and the rotor is mounted for rotation about the stator. 58. The generator of claim 57 wherein: the magnets are high energy product magnets with a predetermined surface area; the magnets are mounted in insets formed in die internal surface of die cylinder; die internal surface of the cylinder includes portions between the insets to form respective consequence poles, each consequence pole having a predetermined surface area; the magnets are disposed widiin the insets, separated from adjacent consequence poles by a predetermined distance; and the surface area of die permanent magnets is greater than the surface area of the consequence poles. 59. The generator of claim 57 wherein the stator includes a central aperture, and the rotor is adapted for mounting on a shaft journaled dirough die stator central aperture. 60. The generator of claim 57 wherein the stator includes a plurality of windings. 61. The generator of claim 57 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. 62. The generator of claim 57 wherein the stator includes: a soft-magnetic core; a first 3-phase star winding, each phase of die first winding including a predetermined number of turns corresponding to a first predetermined voltage ouφut; a second 3-phase star winding, each phase of the first winding including a predetermined number of turns corresponding to a second predetermined voltage ouφut; 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. 63. The generator of claim 62 wherein each phase of at least one winding includes a first portion defined by a tap to provide a diird predetermined voltage ouφut. 64. The generator of claim 57 further comprising a rectification circuit, responsive to signals from the stator winding, for generating DC signals. 65. The generator of claim 64 wherein: the generator further includes a fan mounted for rotation with die rotor; said rotor, stator, rectification circuit, and fan are creating a positive pressure within die housing; the rectification circuit includes heat generating components; and the housing includes respective apertures disposed in predetermined position relative to die heat generating components, creating an air flow over die components through the apertures to cool the components. 66. The generator of claim 65 wherein the fan comprises fan blades disposed on the exterior of the cylinder. 67. The generator of claim 57 wherein the rotor further includes fan blades disposed on die exterior of the cylinder. 68. A method for extending the operating capability of an AC generator, comprising the steps of generating a DC signal; applying the DC signal to a variable frequency invertor to generate an AC signal; generating a control signal to the invertor to vary the frequency of the AC signal in accordance widi current drawn from die generator, to thereby accommodate extraordinary transient demands from loads. 69. A light weight portable genset comprising: an engine with a rotatable ouφut shaft; a generator, comprising a rotor and a stator; the stator including at least one winding and a central aperture, the stator being fixedly mounted concentric with the engine shaft; the rotor comprising a body of soft-magnetic material with a plurality of permanent magnets, each having a predetermined surface area, mounted in insets formed in a surface of the rotor 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 rotor surface proximate to the stator induces portions between die insets to form respective consequence poles, each consequence pole having a predetermined surface area: the surface area of the magnets being greater than die surface area of the consequence poles; the rotor being mounted on die 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. 70. The generator of claim 69, wherein the stator includes a plurality of windings. 71. The generator of claim 69, 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. 72. The generator of claim 69, wherein the stator includes: a soft-magnetic core; a first 3-phase star winding, each phase of die first winding including a predetermined number of turns corresponding to a first predetermined voltage ouφut; and a second 3-phase star winding, each phase of die first winding including a predetermined number of turns corresponding to a second predetermined voltage ouφut; the corresponding phases of die respective 3-phase windings grouped togedier as a unit and wound about die core such diat the corresponding phases of the respective 3-phase windings are in thermal contact with each other. 73. The generator of claim 72 wherein the first predetermined ouφut voltage is on die order of 110 volts, and the second predetermined ouφut voltage is on the order d 12 volts. 74. The generator of claim 72 wherein each phase of at least one winding includes a first portion defined by a tap to provide a diird predetermined voltage ouφut. 75. The generator of claim 74 further comprising: a switch, for selectively effecting a connection to one of the second or diird predetermined voltage outputs; and a rectification circuit, receptive of signals from the switch for generating DC signals. 76. The generator of claim 74 wherein the first predetermined ouφut voltage is on the order of 110 volts, die second predetermined ouφut voltage is on the order of 24 volts, the third predetermined ouφut voltage is on the order of 12 volts. 77. The generator of claim 69, further comprising a rectification circuit, responsive to signals from the stator winding, for generating DC signals. 78. The generator of claim 77 wherein: said rotor, stator, and rectification circuit, are disposed widiin a housing; die housing is formed at least in part of electrically and diermally conductive material; the ratification circuit includes heat generating components connected to ground potential; at least one of die rectification circuit components being electrically and diermally connected to die housing, such diat die housing serves as a heat sink for the components and electrical ground for the rectification circuit. die rectification circuit includes heat generating components connected to ground potential; at least one of die recertification circuit components being electrically and thermally connected to die housing such that the housing serves as a heat sink for the components and electrical ground for the recertification circuit. 79. The generator of claim 77 wherein: the generator further includes a fan mounted for rotation with the rotor; said rotor, stator, rectification circuit, and fan are disposed widiin a housing, rotation d die fan creating a positive pressure widiin die housing; the rectification circuit induces heat generating components; and the housing includes respective apertures disposed in predetermined position relative to die heat generating components, creating an air flow over the components through the apertures to cool the components. 80. The generator of claim 77 further comprising an invertor. responsive to the DC signal, for generating an AC signal. 81. The generator of claim 80 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. 82. The generator of claim 80 wherein the invertor comprises a variable frequency invertor, responsive to indicia of die DC voltage level, for generating an AC signal having a frequency in accordance widi die DC voltage. 83. The light weight portable genset of claim 69, further including a connection mechanism for a carrying strap. 84. The light weight portable genset of claim 69, wherein the permanent magnets are high energy product magnets. 85. The light weight portable genset of claim 69, wherein: the magnets are disposed separated from adjacent consequence poles by a predetermined distance greater dian die distance separating die rotor surface from the stator. 86. The light weight portable genset of claim 85 further including: a mounting frame having a foot portion and a transverse portion widi first and second opposing sides: an aperture formed in die 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 dirough die aperture; and the stator is mounted on die opposite side of die transverse portion concentric with the engine shaft; and die rotor is mounted on the shaft laterally aligned with die stator. 87. The light weight portable genset of claim 86 wherein the mounting frame is formed of a single sheet of material. 88. The light weight portable genset of claim 86 wherein die mounting frame includes a handle portion. 89. The light weight portable genset of claim 89 wherein the handle portion is adapted for connection to a shoulder strap. 90. The light weight portable genset of claim 86 wherein the mounting frame is adapted for connection to a carrying strap. 91. The light weight portable genset of claim 86 wherein: the stator is generally annular with a central cavity; and die rotor is coaxially disposed within die cavity. 92. The light weight portable genset of claim 86 wherein: the stator is generally cylindrical widi a central axial bore; the engine shaft extends dirough die bore; the rotor includes a generally cylindrical central axial cavity and a hub; and die rotor is mounted to die engine shaft at the hub, widi die stator coaxially disposed inside die rotor cavity. 93. The light weight portable genset of claim 69, further including: a mounting frame having a foot portion and a transverse portion widi first and second opposing sides; an aperture formed in die frame transverse portion; and wherein: die engine is mounted on one side d the frame transverse portion overlying the foot, with die engine shaft extending through the aperture; and die stator is mounted on die opposite side of the transverse portion concentric with the engine shaft; and the rotor is mounted on the shaft laterally aligned widi the stator. 94. The light weight portable genset of claim 93 wherein the permanent magnets are high energy product magnets. 95. The light weight portable genset of claim 93 wherein the mounting frame is formed of a single sheet of material. 96. The light weight portable genset of claim 93 wherein the mounting frame includes a handle portion. 97. The light weight portable genset of claim 96 wherein the handle portion is adapted for connection to a shoulder strap. 98. The light weight portable genset of claim 93 wherein the mounting frame is adapted for connection to a carrying strap. 99. The light weight portable genset of claim 93 wherein: the stator is generally annular with a central cavity; and the rotor is coaxially disposed within the cavity. 100. The light weight portable genset of claim 93 wherein: the stator is generally cylindrical widi a central axial bore; die engine shaft extends dirough the bore; the rotor includes a generally cylindrical central axial cavity and a hub; and the rotor is mounted to die engine shaft at the hub, with the stator coaxially disposed inside die rotor cavity. 101. A compact generator, comprising: an internal stator, comprising: a core with respective windings; and a central axial throughbore within the core; an external rotor disposed to rotate around die perimeter of die stator, die 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 die interior side wall of die casing; an engine mount having a central axial stem with an internal bore, wherein the stator is disposed on the mount widi the central axial stem received die central axial diroughbore so that die central axial stem effects an interference m with the central axial throughbore; an engine shaft journaled the internal bore, wherein the internal bore is somewhat larger in diameter than die engine shaft, so mat die engine shaft is rotatable therein, and wherein die rotor is fastened to the engine shaft. 102. The compact generator of claim 101 , further comprising fins formed on exterior side walls of die rotor casing to facilitate cooling. 103. A genset for generating an ouφut signal to a load, die generator comprising: an engine with a rotatable ouφut shaft, the engine rotating the shaft at a rotational speed in accordance with a dirottle control;generator, comprising a rotor and a stator, with the rotor disposed relative to the stator such that relative motion of die rotor and stator causes magnetic flux from the rotor to interact with and induce current in the stator winding, a rectifier circuit, responsive to signals from the stator winding, for generating a DC signal; a invertor, responsive to the DC signal, for generating an ouφut signal of predetermined frequency; and a governor for selectively controlling the engine throttle in accordance with the genset ouφut signal. 104. The genset of claim 103 wherein the governor comprises: a sensor for generating indicia of load demand; means for selectively generating a throttle control signal; and an electromagnetic actuator mechanically coupled to die engine throttle, and responsive to die throttle control signal, for selectively varying the setting d the dirottle. 105. The genset of claim 104 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 die actuator winding to generate a magnetic interaction between die winding and die magnet and cause movement of the magnet and pushrod to vary die setting d die dirottle. 106. The genset of claim 105 wherein the throttle control signal is pulse wid i modulated and die width of the pulse determines die power of die electrical signal supplied to die winding. 107. The genset of claim 105, further comprising a fly-back diode provided across die winding.

Inventors: ANDERSON WILLIAM J, BEDNORZ ARDEL R, DAVIS MITCHELL K, JOHNSON G WEYLIN, SCOTT HAROLD C, TALLY HENRY, ANDERSON, WILLIAM, J., BEDNORZ, ARDEL, R., DAVIS, MITCHELL, K., JOHNSON, G., WEYLIN, SCOTT, HAROLD, C., TALLY, HENRY
Applicants: COLEMAN POWERMATE INC, COLEMAN POWERMATE, INC.
Application year: 1995
Main classification: H02K5
IPC codes: F02B63, F02B75, H02K1, H02K3, H02K7, H02K11, H02K21, H02K29, H02P9