Abstract: When operating a synchronous machine as a synchronous generator, a suppression resistor is required across the main generator field. However when operating the synchronous machine as an induction motor, a current is induced in the main generator field which is typically greater than the current carrying capability of the suppression resistor.In order to overcome the foregoing problem, the present invention provides a centrifugally activated switch for mounting on a rotor and which provides an alternate current path for the induced current.

Abstract: An induction system of the invention is adapted to apply coordinate transformation to the excitation current reference vector corresponding to the primary interlinkage magnetic flux vector reference value and the primary current vector so that they exist in the same coordinate system, thereafter to control the secondary current vector so that the primary interlinkage magnetic flux vector is in correspondence with the primary interlinkage magnetic flux vector, thereby allowing the primary side of the wound-rotor induction machine to function apparently as a voltage source.

Abstract: A brushless capacitor excited alternator includes a rotor assembly having a coil and a diode connected in series with the coil. A stator contains the output coil of the alternator. Also wound on the stator are primary and auxiliary excitation coils. An excitation capacitor is provided with means for connecting it between various terminals on the primary and auxiliary excitation coils, and for connecting the two coils together. The magnetic field and thus the output voltage of the alternator may be varied by connecting the capacitor to different coil terminals.

Abstract: Prior types of generating systems for producing AC and DC output power have utilized integrated drive generators for producing the AC power and means for rectifying the AC power developed by the drive generator to produce the DC power. However, such types of systems encounter various disadvantages, including less than desirable reliability of the DC power, distortion in the AC power caused by rectification thereof to produce the DC power and reduced efficiency. In order to overcome these problems, a hybrid generating system according to the present invention comprises an AC power generating section driven by a prime mover for generating AC output power and a DC power generating section independent of the AC power generating section, also driven by the prime mover for generating the DC output power wherein each of the AC and DC power generating sections includes a permanent magnet generator.

Abstract: The reactive power of an induction machine is compensated by providing fixed capacitors on each phase line for the minimum compensation required, sensing the current on one line at the time its voltage crosses zero to determine the actual compensation required for each phase, and selecting switched capacitors on each line to provide the balance of the compensation required.

Abstract: A stabilized control system and method for smoothly connecting and disconnecting an induction generator to the utility power grid is described. Thyristor switches are interposed between each phase of the mains and the generator. The thyristors are gated so as to decouple the generator from the mains for a period during each mains half-cycle, the decoupling period decreasing as the generator power factor angle increases as the generator is driven by the prime mover to its synchronous speed and above. A feedback circuit processes the generator terminal voltage to produce an analog feedback signal level proportional to the thyristor blocking voltage. The feedback signal is used to increase the thyristor gate delay angle as the generator voltage increases with increasing generator output power. This causes the rate-of-change of the generator voltage with respect to generator speed to be less than it would be with no feedback signal present.

Abstract: A coupling system for an induction motor type generator (10) to an A.C. power line (18) wherein an electronic switch means (28) which is controlled by a control system (30) is regulated to turn "on" at a relatively late point in each half cycle of its operation whereby the energizing power supplied by the line (18) to the induction motor type generator (10) is decreased and the net power delivered to the line is increased.

Abstract: A rotating electric machine comprising a stator 1 and a rotor 5 which is adapted to be rotated about an axis and which is disposed opposite said stator 1. Normally, the magnetic field of the rotor is excited by a direct current which is supplied via sliding contacts. In order to avoid wear of the sliding contacts, the invention employs the measure that the exciting current for the magnetic field of the rotor is supplied via a second stator 13 and a second rotor 9 by means of induction.

Abstract: A circuit for use with an induction generator. The circuit is arranged to initiate operation of the induction generator as a motor to bring the system up to operating speed and subsequently to rearrange the system automatically to cause the induction generator to operate in a generating mode. The automatic reconnection is effected as an incident of the motor reaching a preselected speed. Determination of the preselected speed may be effected by voltage responsive means in one form of the invention, and by centrifugal switch in another form of the invention. The control is effected by suitably selectively connecting the phase winding of the generator. In the illustrated embodiment, a starting capacitor and a power factor correction capacitor are automatically connected at proper times in the operation.

Abstract: The invention is a combination induction generator/synchronous generator power system which finds particular use in aircraft environments. The power system includes an induction generator (36) and a tandem generator (38) enclosed in a single housing (34). The tandem generator (38) includes a tandem synchronous generator (46) which optionally excites the induction generator (36) or provides power to the aircraft systems upon activation of the three-phase contactor (48). The tandem generator (38) also includes a tandem synchronous generator (44) which produces, via a phase controlled rectifier bridge (42), 270 VDC power for the aircraft systems.

Abstract: An electric power generator system including a switched capacitor controlled induction generator adapted to provide power at a regulated voltage and frequency. The system is adapted for autonomous operation for delivery of power with unity power factor to an external power grid.

Abstract: The invention is an aircraft power generation system which utilizes an induction-machine (G.sub.1) as a primary generator of variable-voltage/variable-frequency power. The induction-machine (G.sub.1) is directly driven by the engine (14) and is excited by an excitation-generator (G.sub.2) such that the induction-machine (G.sub.1) operates in a generating mode. A variable-speed drive (20), shown as a toroidal drive (30), controls the excitation frequency of the induction-machine (G.sub.1) such that the negative slip-frequency is controlled as a function of the input speeds (N.sub.1), (N.sub.2) and the electric load on the generator. Control of the toroidal drive (30) and thus speed (N.sub.2) is accomplished by a negative-slip control circuit which includes a drive control logic circuit (36), a proportional actuator (34), a control-start panel (48), and a steering mechanism (32).In another aspect of the invention, the induction-machine (G.sub.1) operates in a start-mode to start the engine (14).

Abstract: The alternator has a stator (12) with a rotor (10) mounted for rotation therein. The armature and field windings (20, 22, 24; 18) are both carried on the stator. The rotor is mechanically driven so as to rotate within the stator. Both the rotor and stator have poles (14; 16) formed at regular spacings on facing surfaces thereof so that as the rotor is rotated, rotor poles rotate past the field poles which are formed on the stator. The rotor poles are regularly spaced about the rotor such that at certain rotor positions all rotor poles are opposed to alternate field poles. Field coils (18a, 18b) are provided, each wound about a corresponding one of the field poles. An excitation circuit (FIG. 4) applies an excitation potential to the field coils such that field coils about adjacent field poles produce oppositely directed magnetic fields. The polarity of the this excitation potential is reversed each time the rotor poles become opposed to alternate field poles.

Abstract: A power generating system for adjustably coupling an induction motor, as a generator, to an A.C. power line wherein the motor and power line are connected through a triac. The triac is regulated to normally turn "on" at a relatively late point in each half cycle of its operation, whereby at less than operating speed, and thus when the induction motor functions as a motor rather than as a generator, power consumption from the line is substantially reduced.

Abstract: A discrete-time, closed loop power factor corrector system controls the coupling of a delta-connected switched capacitor array to a 3- or 4-wire power line which may have time-varying, unbalanced, inductive loads. For inductive loads that cannot be exactly compensated with a delta-connected capacitance, the corrector system minimizes the total RMS reactive current drawn from the power line.

Abstract: A wind turbine drives the squirrel-cage rotor of a capacitively excited induction generator. The amount of excitation is controlled in accordance with the output voltage of the stator and hence the speed of the wind turbine. The generating system is capable of operating at high efficiency over a wide speed range, since the electrical output frequency is allowed to vary with the rotor speed. The electrical power supplied by the induction generator is used for heating purposes within a nearby building.

Abstract: A polyphase rotary induction machine for use as a motor or generator utilizing a single rotor assembly having two series connected sets of rotor windings, a first stator winding disposed around the first rotor winding and means for controlling the current induced in one set of the rotor windings compared to the current induced in the other set of the rotor windings. The rotor windings may be wound rotor windings or squirrel cage windings.

Abstract: A combination exciter/permanent magnet generator for a brushless generator system features a permanent magnet generator wound directly on the exciter structure, while allowing the permanent magnet generator and exciter to be functionally independent of each other. The arrangement is such that the permanent magnet generator provides sufficient voltage under a wide range of speed, load and temperature conditions to turn on power transistors included in a voltage regulator associated with the generator system and to insure adequate system self build-up to a required output voltage without increasing the size of the system as would otherwise be the case.

Abstract: An asynchronous machine including a shaft, a rotor and a stator coaxial with the shaft is provided with a field coil having windings coaxial with and in a plane perpendicular to the machine shaft. The field coil is connectable to a variable DC source for controlling the magnetic flux in the machine. The output voltage of the machine can be controlled without changing the speed of rotation of the machine by controlling the current supplied to the field coil.

Abstract: A non-interruptible power system (NIPS) for generating polyphase A.C. of a substantially constant desired frequency and a substantially constant selected voltage, comprising:(A) a source of interruptible power and a motor energized thereby,(B) a novel generator for producing the desired polyphase A.C.

Abstract: A pulse generator for the generation of pulses which are synchronously associated with the movement of a mechanical part comprises a toothed element, the teeth of which run past a pick-up head, the pick-up head comprising a first winding fed by a carrier frequency, which produces a field which is modulated by the teeth of the element and a second winding in which a voltage is induced by the modulated field, the induced voltage is supplied to a phase discriminator which produces a pulse sequence having a keying ratio proportional to the relative phase position of the induced voltage and the carrier frequency and the pulse sequence is fed to an integration element which produces a voltage signal proportional to the keying ratio.

Abstract: A low frequency, high output alternating current generating device comprising a high frequency generator having an output winding capable of generating a continuous wave high frequency output with an almost constant amplitude, a rectifying means for rectifying the high frequency output of the output winding, a plurality of condition control means for connecting the output of the rectifying means to a load by time-selectively and alternately reversing the polarity of the output, and a reference signal generating means for applying low frequency control signals to each of the conduction control means regardless of the phase of the high frequency output.

Abstract: An improved rotor assembly for a generator used in a multi-channel parallel electrical generating system. A plurality of laminated sections, each having N outwardly extending poles, are stacked to form a rotor. Field windings are wound around the N poles and damper turns are wound around adjacent pole pairs to reduce the mutual flux coupling between the rotor and the stator, thereby reducing the fundamental component of torque between the rotor and the stator.

Abstract: An inductor-type high frequency generator with alternating current field excitation and frequency changing output means. An excitation winding provides current for the field winding by way of a rectifier, and automatic voltage regulator and an inverter. In response to generator output the A.V.R. controls the d.c. voltage fed to the inverter.

Abstract: A plural switch matrix is connected as a direct ac-to-dc converter between an induction generator and an a-c load. The generator provides three-phase output energy which is switched and controlled by the converter, to supply a controlled three-phase quasi-square wave (QSW) voltage to a load. The converter switching provides periodic shorts across the generator terminals, translating some of the mechanical input energy into electrical energy to sustain the generator field. The converter is regulated by gating signals from a combinational logic circuit.

Abstract: A background discussion of induction machine equivalent circuits, including operation as an induction generator, is provided. Selective shorting of the machine terminals is described, to convert at least some of the mechanical input energy into electrical field energy for the machine. Systems are described for accomplishing the selective shorting with a single-phase machine, including sensing of the zero-crossing of the output voltage to insure that the shorting is effected at the appropriate time to replenish the field. The shorting time duration can be varied as a function of load. A three-phase shorting circuit is also described.

Abstract: A background discussion of induction machine equivalent circuits, including operation as an induction generator, is provided. Selective shorting of the machine terminals is described, to convert at least some of the mechanical input energy into electrical field energy for the machine. Systems are described for accomplishing the selective shorting with a single-phase machine, including sensing of the zero-crossing of the output voltage to insure that the shorting is effected at the appropriate time to replenish the field. The shorting time duration can be varied as a function of load. A three-phase shorting circuit is then described.

Abstract: The disclosed voltage generating system includes certain known components, such as an induction machine driven as a generator, the output connections of which are coupled to the normal load connections of a switching system, which can be a bridge-type inverter. The system switching frequency f.sub.1 is regulated by firing pulses from a logic circuit in turn controlled by an oscillator. By controlling operation of the inverter switches with respect to the synchronous frequency (mechanical rotational speed) of the machine, a d-c voltage is provided on the normal inverter bus conductors.In the disclosed system the conventional inverter switches (such as SCR's) are replaced by true two-way power switches, capable of passing current in either direction. In addition the firing signals provided by the usual logic circuit and applied to these power switches are modified so that the switching occurs as a function not only of the first oscillator frequency f.sub.

Abstract: An induction machine is driven to operate as a generator, and has its electrical output conductors coupled to a switching system, which can be an inverter circuit. An oscillator and logic circuit are connected to regulate the switching of the power switches, such as thyristors, in the inverter circuit which operates as a switching system. The thyristors in the switching system are regulated to switch at a frequency sufficiently below the synchronous frequency of the induction machine to enable the machine to build up and operate as a generator. A modulator is connected to the oscillator to vary the oscillator frequency, and thus change the switching frequency of the switching system, above and below a reference level to provide a corresponding a-c output voltage, with a d-c average level, on the d-c bus conductors of the inverter circuit which operates as the switching system.

Abstract: A single rotor, motor-generator set with motor and generator stators and one rotor turning adjacent the two stators. Preferably, the rotor is between the two stators. The rotor has a first rotor periphery facing the motor stator periphery and a second rotor periphery facing the generator stator periphery. There are driver means on the motor periphery and driven means on the rotor first periphery. Also there is a layer of permanent magnet material at least on the rotor second periphery. Furthermore, there is at least one magnetizing station along the generator stator periphery with magnet forming means thereat disposed to form permanent magnets in the rotor permanent magnet material as the rotor second periphery turns past said station with frequency excitation means coupled to said magnet forming means and, there is at least one set of power takeoff elements disposed at least partially around the periphery of the generator stator.