Abstract: A motor-generator set for producing, within a predetermined range, a constant volts/hertz output from the generator. An engine drives an AC generator, the engine having an electronic speed regulator including a first potentiometer for adjusting a speed setting for the engine. The generator has a voltage regulator including a second potentiometer for setting the output voltage of the generator. The first and second potentiometers are ganged for simultaneous adjustment whereby adjusting the potentiometers in one direction increases the speed of the engine and the output frequency and voltage of the generator while adjusting the potentiometers in the other direction decreases the speed of the engine and the output frequency and voltage of the generator.

Abstract: A power supply system for developing electrical power from variable-speed motive power produced by a prime mover includes a differential speed summer having a first shaft coupled to the prime mover and further having second and third shafts coupled to first and second generators, respectively, a power conditioner coupled to the second generator for conditioning the power developed thereby and means for regulating the conditioned power developed by the second generator so that the first generator develops constant-frequency AC power.

Abstract: Method and apparatus for controlling the output frequency of an alternator by maintaining a relatively constant speed of rotation of the alternator rotor are disclosed. The rotor includes an annular stator and a rotor rotatably mounted within. In one embodiment the stator winding is comprised of a plurality of discrete polyphase windings positioned within discrete annular segments of the stator. When the actual rotor speed is below the desired speed, selected stator units are de-energized to decrease the strength of the stator magnetic field, thereby permitting the rotor speed to increase. When the actual rotor speed is greater than the desired speed, selected stator units are energized to increase the strength of the stator magnetic field, thereby exerting a braking force on the rotor to slow it down. In another embodiment each phase of the polyphase stator winding includes a plurality of inductor coils.

Abstract: An output voltage control system for an electric generator having two field windings, wherein a rotary shaft of the generator is rotated by a power source such as an engine, for producing an output voltage. According to the invention, the control system includes a first control unit for supplying an electric current inversely proportionate to the output frequency of the generator to one of the field windings of the generator to produce a substantially constant output voltage for a stationay (fixed) load, and a second control unit for supplying an electric current derived from a portion of the output voltage produced at the generator output to the other of the field windings of the generator in the event of fluctuations in the generator load.

Abstract: A variable-speed power generating system comprises a variable-speed generator electrically connected at its primary winding to an electric power system and its secondary winding to the electric power system through a frequency converter and mechanically coupled to a driver driving the secondary side thereof, a phase detector generating an output signal representing a slip frequency in response to the application of a first input having a frequency component of an output generated from the primary winding of the variable-speed generator and a second input having a frequency component corresponding to the rotation speed of the driver, a controller controlling the frequency converter on the basis of a reference phase provided by the output signal of the phase detector, and regulating means for controlling the frequency converter so that, when the variable-speed generator is disconnected from the electric power system, the frequency applied to the secondary winding of the variable-speed generator may not deviate

Abstract: In a system comprising an asynchronous generator rotatable at variable speeds, and a main electrical network carrying power at a substantially constant voltage and frequency, the improvement comprising a synchronizer having an electronic optimization controller connected in circuit between the generator and the network, the synchronizer being capable of receiving electrical power at variable voltages and frequencies from the generator and controllably and continuously injecting the power into the network at substantially constant voltage and frequency. A method for optimizing the generation of electrical power into the mains is also claimed.

Abstract: An output frequency control circuit is mounted on the rotating shaft connecting a motor and generator. The motor-generator system includes exciter circuits, an input power factor control and an output voltage regulator. The input power factor control ensures that the motor input power factor is unity, which is desirable for motor control. The frequency control circuit responds to variations in the AC power source frequency by generating low frequency excitation to boost or buck the operational speed of the machine, causing the generator output frequency to remain constant at a selected frequency output irrespective of input power source frequency variation. The output frequency may be selected over a given range from a control panel adjustment pot.The major innovation is that the entire frequency control circuit is shaft-mounted and requires no slip-rings or magnetic transformers for signal transfer, thus reducing the possibilities of mechanical failure.

Abstract: A voltage regulator for a diesel engine driven alternator includes speed dip control permitting engine recovery, and a voltage signal circuit and a speed signal circuit producing a linear volts per hertz signal for controlling the RMS voltage of the alternator. A speed sensor is connected to the output of the permanent magnet generator. The signal is a filtered square wave with an accurate 50% mark-to-space ratio and converted to a pulse train coincident with the zero crossovers. A ramp circuit followed by a threshold detector and filter produces a linearly increasing voltage with decreasing speed. A level amplifier produces an output at a selected level. A rate amplifier responds to a derivative of the speed signal and clamps the level amplifier off at speed changes below a selected rate. A large and rapid speed change creates an output signal coupled to the reference side of an error amplifier to unload the alternator. The degree and rate of unloading is limited.

Abstract: In a compound electromechanical assembly having a first singly fed stage mounted for common rotation with a second singly fed stage mounted for common rotation with a second singly fed stage impedance is inserted in inverted connection to form an electrical loop between the secondaries. The impedance includes a resistor and capacitor connected in parallel.

Abstract: An electronic voltage regulator for an ac electric generator precisely controls the generator output voltage and enhances motor starting ability. A filtered dc representation of the output voltage of the generator is produced by circuitry sensing the output voltage of the generator and rectifying to dc and filtering the voltage sense to obtain a relatively smooth dc voltage which is directly proportional to the output voltage of the generator and has on it a small amount of ripple voltage. A dc voltage which is proportional to the frequency of the generator is also produced by circuitry means which senses the frequency of the generator and produces a dc voltage proportional to the frequency of the generator up to a predetermined maximum frequency, not increasing above that maximum, and for amplifying the voltage produced. A comparator circuit compares the dc voltages.

Abstract: The inventive control system introduces the current (.DELTA.I) and voltage (.DELTA.C) deviations simultaneously with the injection set point (C) to define a new injection set point (C') that is utilized in conjunction with the measurement of diesel engine speed (V.sub.rD) to adjust the injection and with the measurement of the injection flow rate C.sub.r to adjust the generator excitation current.

Abstract: An internal combustion engine electrical system is disclosed which is adapted to use an internal combustion engine as a driving source. The generating system is constructed in a manner such that the output of an A.C. generator driven by the engine is rectified by a rectifier circuit, and the output of the rectifier circuit is inverted into an A.C. output by an inverter circuit adapted to use, a commutation command signal, the output of an oscillator circuit which generates a signal of a constant frequency.

Abstract: A primary and at least one backup alternating voltage source are coupled to a common load to provide interrupt free electric current to the load through a simplified interconnecting network. Phase control of all but one of the sources is accomplished by monitoring the phase difference across choke coils coupling the sources to the load.

Abstract: A D.C. excited rotor winding arrangement for a dynamoelectric machine comprises at least one closed loop (1,2,3) of three or more series-connected winding sections (10,11,12,13,16,17,18,19,20,21,22,23) with at least three current-supply terminals (ABCD) at their interconnections. At least one pair of adjacent winding sections (10,13; 11,12) generate opposite magnetic poles when fed in parallel with current from their common supply terminal (such terminals are designated "odd", as opposed to "even" terminals which are each associated with two poles of the same sense) and the pole number is varied by switching the current supply from "odd" to "even" terminals or vice versa. Preferably the winding arrangement comprises a plurality of series-connected closed loops (1) of four winding sections interconnected at two odd (B5, D5) and two even (A5, C5) terminals. Preferably the winding arrangement is fed with current from one of a plurality of rotating rectifiers (4,6,7) according to the pole number required.

Abstract: A variable speed constant frequency generating system for generating constant frequency electrical output power from a variable speed source of motive power includes an exciter for generating excitation current, a main generator for developing the output power, both of the exciter and main generator being driven by a shaft coupled to the motive power source and power converters mounted on the shaft to transfer power between the exciter and the main generator. At shaft speeds below synchronous speed, i.e. that speed which would produce the desired output frequency when DC power is coupled to the main generator field windings, the exciter output is rectified and inverted so that alternating current power of proper frequency is delivered to the field windings of the main generator to maintain the output of the generator at a constant frequency. At synchronous speed, the power converters transfer substantially only DC power to the main generator windings.

Abstract: A method and apparatus for governing a generator which generator comprises micro-hydropower generating equipment usable in run-of-the-stream situations. A plurality of dump loads are associated with the electrical output of the generator and changes in frequency of the output phase voltage of the generator are detected. The dump loads are switched into or out of association with the generator in response to the frequency changes so as to cause substantially compensating frequency changes. The rate at which the compensating frequency changes occurs are damped desirably by use of a flywheel.

Abstract: A voltage regulator is described adapted for use controlling the output of an AC generator. A voltage control field-winding excitation control circuit supplies direct current to the generator field in response to a driver. The driver, in turn, is operated in response to a switching regulator. A frequency sensing means generates a voltage proportional to the frequency of the generator. This frequency sensitive voltage is combined with a reference voltage to drive an asynchronous switching regulator. The switching regulator produces a train of output voltage control signals to operate the driver. Preferably power MOSFETs are used to control the flow of current to the generator field. Loss of voltage and high current protection features are included.

Abstract: A control system for a stand-alone electrical generator driven by a prime mover such as a wind turbine in which switches are operable in response to changes in the frequency of the generator output to change the load imposed on the generator by resistor means. The resistor means includes domestic resistive heaters and dump resistors, the switches for the former turning "on" at frequencies lower than those at which the latter turn "on". The frequencies at which the several switches in a given consumer's premises switch "on" are interlaced with the frequencies of the switches in other premises so as to avoid discrimination between consumers. The output frequency is thus kept relatively constant despite changes in wind speed.

Abstract: A variable-speed constant-frequency alternator compensating for changes in speed of the prime mover by electromagnetically rotating the rotor's magnetic poles around the rotor. If the prime mover has a rotational speed above or below that required to produce the desired output frequency, the magnetic poles rotate about the rotor in a forward or reverse direction, respectively. To connect the alternator to an external a.c. source, the alternator's controls match its output to the precise amplitude frequency, and phase of the external source. The rotor, for each magnetic pole pair, includes three windings. Three-phase power in these windings, produces the magnetic pole pair and rotates it relative to the rotor. Each winding couples to a flopper circuit having k sets of resistances. The resistances, taken in turn, have an inverse proportionality to the magnitude of the desired sine wave for the three-phase current in the rotor's windings.

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: In a motor-generator set, the frequency of the AC generator outputted voltage is automatically adjusted by field winding regulation of the DC motor, through a closed loop in which a dual-slope converter is charged during a clock-defined time interval in accordance with a potentiometer setpoint, and the charging plus discharging period of the dual slope converter encompasses the period of the outputted voltage.

Abstract: There is provided a static VAR generator having voltage regulation in combination with the capability to damp subsynchronous resonance should it occur. A novel method for controlling subsynchronous resonance is provided by monitoring the frequency of the electrical generating system and controlling the insertion of compensating inductance in response to disturbances that may result in voltage and frequency pulsations.

Abstract: A variable frequency drive for a motor-generator/alternator set which is used to supply electrical power to computer or data processing equipment. Power failures in commercially supplied power results in aberrations and erroneous computations in computers and data processing equipment. An induction motor is used to drive a generator/alternator. The induction motor is driven below the synchronous speed of the generator/alternator and a variable speed drive increases the velocity supplied to the generator/alternator, preferably to a point above its synchronous speed. Therefore, when there is a commercial power failure, the generator/alternator remains within a desired frequency range for a longer period of time than a comparable generator/alternator driven at synchronous speed.

Abstract: An electrical alternator system is capable of being driven by either of two prime movers and of being automatically transferred therebetween without substantial variation in the electrical output of the alternator. A planetary gear system having two mechanical drive inputs and one output is interposed between the normally used prime mover and an alternator. One mechanical input to the planetary gear system is provided with a controlled variable speed input N.sub.R from the prime mover which is controlled so as to compensate for speed variations in the other mechanically input N.sub.E from the prime mover thus maintaining the output speed N.sub.S substantially equal to a desired reference speed N.sub.O.

Abstract: There is provided a static VAR generator having a novel method for controlling subsynchronous resonance by monitoring the frequency of the electrical generating system and controlling subsynchronous resonance by phase-firing thyristor controlled inductance.

Abstract: An alternating current power source apparatus comprises an AC generator having a field coil which is driven by an engine; a first rectifier having one or more thyristors which rectify the AC output of the AC generator; a second rectifier having one or more thyristors which is connected in parallel to said first rectifier to give the output having a polarity reverse to the polarity of the output of said first rectifier; an AC driving load connected to said first and second rectifiers; a voltage control device for controlling the output voltage of said generator to a predetermined value by controlling a field current passing through said field coil; an oscillator for oscillating at a desired frequency; and a gate signal generating circuit which is controlled by the output of said oscillator so as to feed a turn-on signal alternately to said gate circuit of said first rectifier and said gate circuit of said second rectifier.

Abstract: A frequency control system for an n-phase induction machine having an input shaft and at least one output line, where n is an integer. The system includes a generator that provides an electrical frequency control signal, f.sub.e, which is representative of the difference between the phase of the voltage on the output line and the phase of a reference signal. The system further includes a generator for providing a mechanical frequency control signal which is representative of the frequency of rotation of the input shaft to the induction generator. Another generator provides a torque generator control signal which is representative of the difference between the electrical frequency control signal and the mechanical frequency control signal. A torque generator, such as an internal combustion engine, is adapted to be responsive to the torque generator control signal for applying a torque to the input shaft of the induction machine, where the applied torque is related to the torque generator control signal.

Abstract: The input signal corresponding to the respective frequency or power variation is supplied both to the inputs of the discrete filters and to angle measuring devices assigned to them, of which only the tuned filter in conjunction with its angle measuring device actuates a switch which sends the filter output via angle rotating and matching elements to a MAX selector element, from which the supplementary damping signal for the excitation is tapped. For low oscillation frequencies a low-press filter is provided which, via mean value formers and time delay multivibrator stages, permits a regulator signal to become operative for the excitation, delayed or undelayed, when certain limit values are exceeded.

Abstract: The present invention relates to a generator system connected to an external A.C. power source for supplying electrical A.C. power to a load for prolonged periods when the external electrical A.C. power source fails. The system comprises a main A.C. generator unit capable of generating an A.C. potential at a selected frequency and voltage for the load, and an auxiliary A.C. generator is connected to the main generator for generating A.C. at a high frequency. This high frequency A.C. is conveyed to a relatively small high speed motor and flywheel unit in a sealed chamber, which unit at full speed can store large amounts of rotational kinetic energy. The high speed motor has a stator armature with a power winding and an excitation coil, and a cooperating rotor of soft magnetic material having a cylindrical surface with a layer of magnetizable permanent magnet material thereon. When energized with the high frequency A.C., the power winding causes the rotor to rotate as a hysteresis motor.

Abstract: A system for supplying power to a field winding to maintain excitation of an alternating current generator during excessive output current conditions, the generator having a plurality of output lines for supplying power to a load and the field winding being supplied during normal operating conditions by a shunt type voltage regulator responsive to the output voltage of the generator. The system includes a current transformer having a primary winding in series with an output line of the generator, a secondary winding, and a tertiary winding shunted by a capacitance. A rectifier circuit rectifies the voltage supplied by the secondary winding, the output terminals of the rectifier circuit being connected in series with the regulator output terminals to supply power to the field winding. A control circuit, connected to the output of the generator and responsive to output current conditions enables the rectifier circuit output during excessive output conditions.

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 shaft of a wind turbine is connected to the rotor of a three-phase AC generator. The rotor windings, in turn, are connected to the rotor windings of a DC-energized, AC exciter via a differential frequency-converter. A frequency-detector, which monitors the output of the AC generator, is connected to the input of the frequency-converter to maintain the output of the generator at 60 Hz. A "real" power sensing circuit, connected to the output of the generator, develops a control signal which, when subtracted from a second control signal generated by a power management control circuit, maintains the power output of the generator at the maximum possible level for each particular power output from the wind turbine which drives the generator.

Abstract: A dynamo with a stationary armature and with two rotors, with the frequency of the armature current the same as the frequency of the field excitation and independent of the speed of rotation of the rotors. The rotors have opposite instantaneous magnetic polarities, are magnetically connected and rotate in opposite directions on concentric shafts. Field excitation may be dc or single-phase ac. Disk or tubular rotor and stator structures may be used. Dynamos according to the invention may function as a d-c generator, an a-c generator, an amplifier, as a-c or d-c rotary transformers, and as a-c or d-c motors.

Abstract: A generator set includes a prime mover and a three-phase asynchronous electrical machine coupled to this prime mover and acting as a generator. In addition, at least one set of three delta-connected excitation capacitors is provided, the vertices of the delta-connection each being connected to a respective phase of the electrical machine. A respective inductor is connected in series with each of the said capacitors so as to form at least one set of three L-C series resonators. The resonant frequency of the or each set of resonators is substantially equal to a corresponding predetermined odd harmonic of the frequency of the voltage delivered by the generator. In parallel with each phase of the electrical machine there is also connected a saturable reactor acting as a voltage regulator.

Abstract: An energy utilization circuit and method energizes a.c. loads with a.c. power of conventional voltage and frequency characteristics. A coverter responsive to an energy source, typically a wind or solar driven generator, converts the energy to d.c. electrical power. An inverter alters the d.c. power to a.c. power. An a.c. wave generator, such as an alternator, is connected to the output of the inverter. The alternator is operated to impress its voltage and frequency on the output of the inverter so as to lend conventional characteristics to this output. Excess power from the inverter maintains the operation of the alternator.

Abstract: The present invention is directed to a novel frequency regulator which controls a generator output frequency for variations in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices.

Abstract: A frequency control utilizing a reference oscillator and a signal controlled oscillator is disclosed. The frequency control maintains the frequency of an output signal at the same frequency as the reference oscillator if there is no signal present at a frequency control input. A signal at the frequency control input causes the frequency of the output signal to be varied accordingly. The frequency control contains a feedback loop which compares the output of the signal controlled oscillator with the fixed frequency of the output of the reference frequency oscillator. The frequency control of the present invention has particular applicability as a frequency control for parallel-connected AC systems.

Abstract: A prime mover delivers rotational torque to a generator having an exciter and a main unit connected sequentially along the prime mover output shaft. A voltage sensor is connected to the generator output and supplies a signal reflective of the output voltage to a frequency source. The frequency source is connected to receive power from a secondary energy source associated with the prime mover. The frequency source supplies an output signal at a preselected frequency at variable power levels related to the magnitude of the generator output voltage. The frequency source output is connected to the stator of the exciter to generate the magnetic field therein which rotates directionally with respect to the rotational direction of the prime mover output shaft to generate an output of preselected frequency.

Abstract: An AC synchronized generator includes an exciter stage and a generating stage, the exciter stage comprising an exciter stator connected for excitation to any conventional AC source and an exciter rotor driven in rotation therein by any convenient source of rotary power. The exciter rotor is mounted for common rotation with a generator rotor, the windings of the exciter rotor being connected in subtraction, or in an inverted connection with those of the generator rotor. A generator stator is then used to produce the current to a load. In this form the rotating magnetic field of the exciter stator will be added to the angular rate of the exciter rotor, which is therefor induced at an AC rate corresponding to the sum of these two angular rates. The generator rotor, being electrically connected in opposite direction but driven along with the exciter rotor, will carry a magnetic field which travels as the difference between the magnetic field in the exciter rotor and the rotor angular rate.

Abstract: The method for regulating the terminal voltage delivered by an independent alternating-current generator consists in measuring the voltage in at least one phase, in measuring and automatically adjusting the frequency with respect to a reference value by putting dissipative resistors in circuit, and in automatically varying the reference value of the frequency as a function of variations in voltage. The invention achieves stable voltage control which prevents harmful oscillations and is applicable in particular to asynchronous generators which are driven by a natural fluid.

Abstract: This invention relates to a generator system for generating a readily controllable A.C. of a selected potential and of a substantially constant selected frequency, which system comprises a first, or master, rotary generator producing an A.C. potential of substantially constant frequency and at least one other, or slave, rotary generator producing an A.C. potential of a frequency identical to that of the first generator, the A.C. potential outputs of all the generators being combined in series, and electrical means for shifting the phase of the A.C. potential of the slave generator with respect to the phase of the A.C. potential master generator whereby the resultant combined A.C. outputs constitute an A.C. potential of the selected value and being of the substantially constant selected frequency.

Abstract: Apparatus for detecting the presence of subsynchronous current components in an electrical generating or transmission system is disclosed. Input signals, representative respectively of line voltage and current, are conditioned and initially filtered to suppress high frequency noise. The input voltage signal is further limited and filtered to produce a constant amplitude, sinusoid reference. The input signals are then multiplied to yield the subsynchronous current signal components, if any, which undergo further filtration by a bandpass filter circuit. In addition, the detection apparatus is provided with circuit means for insuring protection against overvoltage and current surge conditions.

Abstract: A starting apparatus for a gas turbine-generator mounted on an electric motor driven motorcar includes a gas turbine and an A.C. generator with A.C. output terminals coupled directly to the turbine. A rectifier with D.C. output terminals is connected to the A.C. output terminals of the A.C. generator. A battery device is connected to the D.C. output terminals of the rectifier. An inverter has D.C. input terminals connected to the floating battery device in parallel and A.C. output terminals from which an A.C. output is derived. A control circuit is connected to the inverter for controlling the speed of the motorcar. At least one A.C. motor energized by the A.C. output of the inverter for driving the motorcar is provided. A switching device connects the A.C. output terminals of the inverter to the A.C. output terminals of the A.C. generator when the gas turbine is started and connects the A.C. output terminals to the A.C. input terminals of the A.C. motor after the gas turbine is started.

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: A system for generating alternating current of selected voltage at a target frequency includes a plurality of A.C. generators, at least one of which has a rotatably mounted stator. A prime mover drives a power input shaft at speeds extending through a wide range and the shaft is connected to the first rotor. As speed increases, the generator reaches the desired frequency and a sensing device releases the stator to rotate and maintain a relative speed between itself and the rotor corresponding to the target frequency. The stator drives the second rotor at its own absolute speed which is the difference between the power input shaft speed and the relative speed between the first stator and rotor. A field control maintains the desired voltage and a load control transmits the current output to a load and varies the load to maintain the generator at proper operating condition.

Abstract: Power system stabilizers are used in the excitation systems of large shaft driven synchronous dynamoelectric machines for the purpose of enhancing the dynamic stability of power generating systems. Such stabilizers using speed, power or frequency as an input signal when applied with high initial response excitation systems are effective in damping low-frequency local or inter-tie mode oscillations which may occur in the system. The power system stabilizer may adversely affect torsional damping at higher frequencies. The adverse effects of a power system stabilizer at shaft torsional frequencies are obviated by providing a torsional oscillation protection device comprising a composite band-reject filter of the present invention which attenuates the power system stabilizer output at the shaft natural torsional frequencies without introducing an excessive phase lag at the local or inter-tie mode frequencies.

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: An electrical generator arrangement includes a variable-ratio drive device, an alternator driven by the drive device and a generator which is separately excited by the alternator output. An over-running clutch connects the alternator and generator rotors so that in the event of an alteration in the driving output from the drive device the generator can continue to rotate with its normal speed and direction but the frequency of the alternator output provides an indication of the operating state of the drive device.

Abstract: A constant frequency a.c. generating system includes an alternator driven at a variable speed. A rectifier provides a d.c. supply for a rotary inverter. To maintain the voltage and frequency of the inverter output constant, the frequency is monitored and used to control the alternator field current and the voltage is monitored and used to control the inverter field current in a regulator circuit.

Abstract: A dynamic stabilizer which includes a voltage generator connected in series with the output terminals of a synchronous AC generator provides compensation for voltages produced by the main AC synchronous machine which compensation is provided to overcome the effects of torsional oscillation between masses in the main AC generator system. Torsional oscillations may exist between the masses of turbines driving the AC generator, the exciter mass for the AC generator, and the mass of the rotor of the generator. Shaft angular velocity is sensed and provided to a frequency discriminating filter since the speed is proportional to the torsional oscillation and since a reference signal is provided to the frequency discriminating filter, the frequency discriminating filter provides an output signal which is proportional to the reference signal plus and minus the frequency of the torsional oscillation. This signal is provided to the previously named series connected generator where a 180.degree.