Abstract: To improve the resistance against external low-frequency disturbance (represented by generator output change), the power system stabilizer for a generator, for inputting a voltage regulating signal (e), as an auxiliary signal, to an automatic voltage regulator to control a generator terminal voltage at a target voltage (V.sub.o), comprises: an angular acceleration observer for calculating an estimated angular acceleration change rate (.DELTA.as) of the generator on the basis of at least one of stabilizing signal change rates (.DELTA.P and/or .DELTA..omega.) of the generator; and a power stabilizer circuit for calculating a corrected voltage regulating signal (e) applied to the automatic voltage regulator on the basis of the estimated angular acceleration change rate value (.DELTA.as) calculated by the angular acceleration observer. Further, it is preferable to provide a plurality of observers and a plurality of power stabilizer circuits, separately for each fluctuation frequency.

Abstract: A dynamic mechanically-switched damping (DMSD) system is described which utilizes one or more mechanical switches and appropriate controls to switch series or shunt reactive impedances in order to provide power oscillation damping in power systems. The DMSD system provides a controller which can be configured based on the number of mechanical switches in the DMSD system, the type of reactive impedances interfaced to the power system by each switch and the magnitude of each of the reactive impedance. The DMSD system monitors parameters of the power system and the controller generates a modulation signal based on the monitored parameters. The modulation signal is processed to identify a reactive impedance of the available DMSD system reactive impedances required to damp power oscillations. Appropriate switches are selected for supplying the required reactive impedance.

Abstract: The stabilizer for power system is capable of suppressing power unstableness quickly and functioning effectively to a plurality of power disturbances even if the non-linearity of the power system becomes more intense because the stability point is moved from optimum stability. A phase difference calculating circuit calculates the phase difference between the internal phase angle of a generator and the voltage phase in a secondary bus line of a main transformer connected to a synchronous generator. A power system stabilizer produces an auxiliary signal based on the output of the phase difference calculating circuit. A first nonlinear compensating circuit and a second nonlinear compensating circuit produce compensating signals for compensating the non-linearity of the power system in order to compensate the output of the power system stabilizer.

Abstract: In a generator starting apparatus, in which commercial frequency electric power supplied from an electric power system is converted into variable-voltage variable-frequency electric power to thereby start a gas turbine generator, a harmonic-component removing apparatus is provided which removes harmonic components contained in the converted variable-voltage variable-frequency electric power on the basis of the detected harmonic components. In addition, an apparatus for removing harmonic components generated in an electric power equipment is provided, wherein harmonic components contained in an electric power system are detected so that they may be removed.

Abstract: An alternating current generator having a first Y-form three-phase connecting circuit including three first windings connected with each other in a Y-form, a first rectifying circuit for rectifying currents output from output terminals of the three first windings, a second Y-form three-phase connecting circuit including three second windings connected with each other in a Y-form, and a second rectifying circuit for rectifying currents outputted from output terminals of the three second windings. The three first windings are inserted in slots of a stator core so that the three first windings have phase differences of approximately 120 degrees from each other.

Abstract: An improved power system control apparatus which reduces power fluctuations and includes an estimated unit for estimating the system impedance and phase difference angle using the generator power transmission terminal voltage, the reactive power and effective power of the system. The invention enables accurate power system impedance estimates in a real-time manner. The invention can be applied to a filter device for removing noise components from an angular velocity signal. The filter device comprises first arithmetic means for calculating changes in phase angle, second arithmetic means for calculating changes in angular velocity, a first integrating for integrating the changes in the phase angle to obtain an estimated phase angle, a second integrator for integrated the changes in angular velocity to obtain an estimated angular velocity and a power stabilizing filter for filtering the estimated angular velocity signal.

Abstract: A charging generator for a vehicle comprises a three-phase a.c. generator in which first and second armature windings are provided so that the waveforms of the a.c. voltages produced in the first and second windings have a phase difference of 30.degree. in electrical angle, each of the output voltages are rectified in each rectifier, and the output side of the rectifiers are connected in parallel so that the output voltages are composed, whereby the height of ripple of the produced d.c. voltage can be reduced.

Abstract: A circuit and a method for filtering the ripple in an output of a multi-phase alternator in a vehicle system having a regulating circuit that regulates the output of the alternator includes a switch connected in series between a system voltage and the input of the regulating circuit, and circuitry for closing the switch at a predetermined phase of the voltage of at least one of the stator windings of the alternator. The circuitry for closing the switch operates to close the switch at a conduction switchover point among the stator windings in synchronism with a voltage waveform of the at least one of the stator windings, and is timed to produce an aliased waveform for application to the regulator. The output of the switch is applied to an integrator for integrating the output voltage from the alternator during an entire time cycle period of one of the windings of the stator coils for application to the regulator.

Abstract: A power system control apparatus has a power system impedance estimating circuit for estimating a power system impedance from an internal power of a generator, determined by an internal current thereof, and from a terminal voltage of the generator, and having a power system impedance estimating table, a power system stabilizer for suppressing a power fluctuation in power system in accordance with the estimated power system impedance, and an auto voltage regulator for keeping an output voltage of the generator at a constant value during a normal operation.

Abstract: In the alternating current generator for vehicle, an armature coil comprises a Y-connected first three-phase armature coil and a delta-connected second three-phase armature coil whose phase windings are inserted into same slots respectively. Each of the three-phase armature windings is provided with rectifying means for converting respective a.c. output into a direct current. The direct currents are summed to provide an output of the generator. It is effective to use a plurality of rotary magnet poles provided on a shaft of the generator for a compact a.c. generator in which the radial dimension of the rotary magnet poles is reduced.

Abstract: A voltage regulator for regulation of automotive electrical generators and battery system. A generator is coupled through a rectifier to a voltage regulator and a battery. The regulator is activated by a low voltage level stator signal from the generator. The activation voltage level is set to an improved initial activation time when the generator starts to charge the battery while maintaining tolerance to rectifier leakage current. A feedback is included in the regulator to lower power dissipation during regulation and protect the regulator during a voltage surge.

Abstract: A subsynchronous resonance mitigation system, including a method and apparatus, for damping undesirable subsynchronous resonance oscillations in a generator, which, if left unchecked, may damage the shafts of a turbine-generator set. A remote coupling apparatus, such as a thyristor controlled series capacitor (TCSC) system, a sourced inverter device, or a static phase shifter, is coupled to the generator by a transmission line. In response to a firing command, the coupling apparatus introduces subsynchronous resonance mitigating currents into the transmission line. Sensors monitor power line parameters and/or the generator speed, and in response thereto, a higher-level controller generates a voltage command. A vernier controller responds to the monitored power line parameters and the voltage command to provide the firing command to the coupling apparatus.

Abstract: A dynamic braking system resistor for stabilizing a power system during power system disturbances includes a braking resistor for coupling with a power system bus. A controller monitors a power system parameter, such as the speed of a generator coupled with the power system bus, and determine therefrom a thyristor control signal. The controller uses the power system parameter to establish a desired modulation and then provides a bias to the desired modulation. The controller conditions the biased desired modulation signal to provide the thyristor control signal. A thyristor valve responsive to the thyristor control signal couples the braking resistor with a ground potential. A method is also provided of damping subsequent oscillations on a power system following a power system disturbance using the dynamic braking resistor.

Abstract: The power supply system for a motor vehicle, includes a battery; a three-phase generator; a connecting line connecting the terminals of the generator and the battery; a rectifier connected electrically to the generator; a voltage regulator for switching an exciter field of the generator on and off to control a voltage actual value at the generator terminals and producing an average field current in the exciter field to maintain a power supply voltage substantially constant regardless of load and speed; and a circuit device for determining and for partially compensating an undesirable direct voltage drop at the generator terminals resulting from a voltage drop in the connecting line caused by load current. The device for determining and for partially compensating is structured to determine an alternating voltage at the generator terminals produced by an alternating current component in the connecting line.

Abstract: A brushless electrical power generating system (10) in accordance with the invention includes a main generator (16) having a rotor (30) on which is wound a field winding (32) and a stator (112) on which is wound a winding (36) for producing an alternating current electrical output having at least one phase; an exciter (14) having a rotor (24) mounted coaxial to the rotor of the main generator and a stator (110) on which is wound a stator winding (18) and an electrical field shield (40) disposed between the stators of the exciter and the main generator for shielding the winding of the stator of the main generator from an electric field produced by the winding of the stator of the exciter whereby capacitive coupling of any electrical noise present within the current flowing in the stator winding of the exciter to the alternating current electrical power output is reduced.

Abstract: The present invention relates to an electrical protective circuit, used when abnormality occurs, in a vibration suppressing apparatus which changes the load torque on a generator such as an alternator fixed on the engine to generate an angle moment on the generator body to cancel rough idling engine vibrations to suppress vehicle body vibrations due to the rough idling. In the inventive vibration suppressing apparatus, a generator is fixed on the engine which generator includes a voltage regulator to control a field winding current such that a fixed voltage is output to a battery. The generation of engine rough idling is detected on the basis of either a change in the engine speed or a change in the engine vibrations. If rough idling is detected, a high voltage circuit is connected to the field winding to increase the field winding current and hence the load torque on the generator.

Abstract: A noise filter for the zero crossing detector of a digitized sine wave signal uses an adjustable noise integrator. The noise integrator incorporates a counter. The integration characteristic of the counter is adjustable by selecting a count rate or a count limit from a microprocessor memory.

Abstract: A control for a DC link power conversion system including a brushless generator having a main generator portion including an armature winding and a rectifier coupled to the armature winding of the main generator portion which converts AC power developed therein into DC power on a DC link comprises a circuit for sensing a parameter of the DC power, a circuit coupled to the sensing circuit for generating an alternating current waveform having a harmonic content dependent upon the sensed DC power parameter and a circuit coupled to the generating circuit for modifying the AC power developed in the main generator armature winding with the alternating current waveform so that the DC power has a certain AC component superimposed thereon.

Abstract: A brushless electrical power generating system (100) in accordance with the invention includes an exciter (14) for producing alternating current from an exciter rotor; a rectifier (20) mounted for rotation with the exciter rotor for producing a rectified control current from the AC current; a common mode inductor (112), coupled to the control current, for cancelling common mode noise components within the rectified control current; and a main generator (22), having a rotating field winding (24) mounted on a main generator rotor excited by the control current and producing an alternating current power output from a stator.

Abstract: In a system for stabilizing the operation of an electrical generator connected to a power distribution network, which system includes a power system stabilizer operating through a modulator circuit to control generator oscillations, there is included a scheme for testing the integrity of the power system stabilizer and modulator circuit which involves the application of a test signal having known values to the power system stabilizer. This test signal propagates through the circuitry and the resultant output is demodulated to be compared with a stored representation of the test signal to thus yield outputs representing the gain and phase shift of the power system stabilizer and modulator circuit in combination.

Abstract: A power system stabilizer (PSS) to bring the constant in a phase lead-lag circuit of the PSS to an optimum value by having such procedures carried out in its phase lead-lag compensation circuit as to apply the ruler to lead the phase of the PSS when the period of the power fluctuation in each mode tends to decrease and to lag the phase of the PSS when conversely the period tends to increase by means of a fuzzy inference device to detect results of the periods weighted by the degrees of the tendency, to superpose the outputs obtained by application of the rule to obtain the center of gravity, and therewith finally to vary the constant in the amplification and phase lead-lag circuit of the PSS.

Abstract: A switchable filter has characteristics (e.g., time constant) that are changed by a low offset, bipolar switch that is turned off and on to periodically connect/disconnect an additional circuit element to the filter. The preferred embodiment is specially designed for use in an automotive voltage regulator.

Abstract: A regulator for a vehicle charging system senses when it applies and terminates excitation to the field winding of the charging system's alternator. When the excitation is applied to the field windings, the output of the alternator is connected to an input filter in the regulator so that the regulator can sense the alternator's output. When the excitation is terminated, the input filter is disconnected from the alternator's output to isolate the filter from voltage steps induced in the alternator's output by the turn-on and turn-off of the field excitation.

Abstract: A variable speed, constant frequency electrical generating system has a variable speed, engine driven generator. The system operates in either a generate or an engine start mode. A bidirectional filter connected between the rectifier-converter and the AC bus traps or blocks switching harmonics from the rectifier-converter. Shunt trap circuits are connected either phase-to-phase or phase-to-neutral.

Abstract: A scheme for stabilizing a synchronous alternating current generator through the excitation control to dampen generator oscillations includes a power system stabilizer responsive to signals representing the generator output voltage and output current to provide an oscillation signal which represents the instantaneous magnitude of the generator oscillations. A modulator means is included which develops a signal, representing the generator voltage with respect to neutral, and this latter signal is multiplied by the oscillation signal to provide a control signal which controls the excitation of the generator.

Abstract: Pulsations in an electrical parameter on the output of a synchronous generator powered by a Diesel engine at a frequency which differs from that of the synchronous generator's natural frequency are smoothed out, whereby, a controlled variable (X) corresponding to the pulsation is tapped from the stage formed by the Diesel engine (5), the generator (3), and the network (4). From this controlled variable (X) and a reference input (W), a control difference (.DELTA.) is calculated, by means of which a correcting variable (y) is set in the stage indicated for the purpose of control.

Abstract: A method by which a turbine generator (1, 2, 3) can be protected against sub-synchronous frequencies occurring in an electric network which is connected to the turbine generator and which incorporates capacitors. The method is based on de-equalizing the subsynchronous natural frequencies of the three phases, so as to weaken the coherence of the frequencies. This is achieved by incorporating in each of two of the phases a respective inductance L of mutually different size and by changing the capacitance equivalently with a series capacitance C such as to fulfill the condition 1/LC=.omega..sub.o.sup.2, where .omega..sub.o is the network frequency.

Abstract: Damping of supersynchronous oscillations in an ac power system is accomplished by a damping circuit connected between a power line and a system neutral potential. The damping means includes a tuned circuit having a resonant frequency above the system operating frequency. Preferably, the tuned circuit further has an antiresonant frequency at the system frequency. The supersynchronous damping circuit in accordance with the invention can be used with subsynchronous damping circuits known in the prior art to enhance the damping of oscillations in the ac power system.

Abstract: A digital filter for a power system stabilizer in a generator power system. The filter comprises a multi-stage filter having a low DC gain, a phase lead in the region of power oscillations (approximately 0.1 to 2 hertz) of the power system, a torsional reject characteristics (approximately 13.5 to 45 hertz) associated with mechanical resonances of the system, and high attenuation at the fundamental power frequency (e.g. 60 hertz). The filter is comprised of four digital filter sections, the first providing a lead and lag characteristics, the second and third providing a torsional reject characteristic, and the fourth providing a substantially zero DC gain characteristic for the elimination of any DC signal offset as well as a line freqeuncy notch, which tracks the fundamental line frequency.

Abstract: The power system stabilizer is provided at an individual power system to be separated due to an accident cutting off a link line which interconnects a number of power systems to form a large-scale power system. The power systems include power stations such as power plants and transformer substations. A simplified arithmetic processing unit of the stabilizer performs an arithmetic processing by a simple linear equation using an output frequency of a representative power station belonging to the separated power system immediately after the accident has been cleared, so that a total load drop of the separated power system can be assumed. Based on the assumption amount, balance control of demand and supply in the separated system is made.

Abstract: A high-power, high-voltage DC power supply includes a plurality of AC generators, each of which includes a rotor and one or more sets of armature windings wherein the rotors are linked together. A plurality of rectifiers are connected together in series and the armature windings are connected to the rectifiers such that each rectifier produces a fractional voltage which is combined with the fractional voltage developed by other rectifiers to develop a combined output voltage across all of the rectifiers. The armature windings are placed relative to one another such that a plurality of equally-spaced ripple peaks appear in the combined output voltage for each 360.degree. of each armature winding voltage. This in turn minimizes ripple magnitude leading to a desirable decrease in the overall power supply size and weight.

Abstract: An alternator of the single-phase type in particular is composed of an armature (1) provided with at least one winding (2) and an inductor (3) comprising on the one hand a magnetic circuit (4) having at least one pair of poles (5) with lateral pole shoes (6) and on the other hand at least one excitation winding (2) formed around said magnetic circuit (4), the inductor (3) and armature (1) being rotatable with respect to each other. At least one pole (5) is provided in the vicinity of at least one pole shoe (6) with a slot (9) occupied by a corrector winding (8) which embraces the pole shoe (6) and is connected electrically so as to permit the flow of substantially direct current through the corrector winding during service.

Abstract: An apparatus for stabilizing turbine generator shaft torsional oscillations including: a current detector for detecting ac current of a turbine generator used in combination with a dc power-transmission system, a filter to which an output of said current detector is delivered, the filter comprising a first bandpass filter for detecting a sub synchronous component (f.sub.l -f.sub.m) and a second bandpass filter for detecting a super synchronous component (f.sub.l +f.sub.m) where a fundamental freuency of the generator is represented by f.sub.l and a natural frequency of the mechanical shaft system of the generator is represented by f.sub.m, a calculation circuit for applying conversion of at least one of d and q axis to respective outputs from the first and second bandpass filters using a generator phase .theta..sub.G to take out at least one of .DELTA.i.sub.d and .DELTA.i.sub.

Abstract: This invention relates to a power system stabilizing apparatus for a synchronous generator, which comprises two power system stabilizers for raising the stability of an electric power system. The characteristics of one stabilizer is preset so as to increase the braking power in the same way as in a conventional power system stabilizing apparatus, while the other one being preset so as to increase the synchronizing power, so that phase compensation elements of both power system stabilizers can be varied in accordance with the drift amount of the generator such as the revolution deviation of the rotor thereof, the output deviation thereof, the frequency deviation of the terminal voltage thereof, etc. thereby realizing high static and transient stability.

Abstract: A self-excited brushless AC generator as a single or polyphase main winding, a generator field winding, an exciter device for drawing current from the main winding for energizing the generator field winding when the main winding is under no load and normal load conditions and an auxiliary exciter system responsive to the generation of a harmonic of the generator fundamental flux to supply current to the exciter device for energizing the field winding when the main winding is under short circuit conditions. The auxiliary exciter system has an auxiliary winding wound with the main winding so as to be responsive to generation of the harmonic flux and an automatic voltage regulator. The regulator has a first input coupled to the auxiliary winding, a second input coupled to an output of the generator and an output coupled to an exciter field winding which is inductively coupled to an armature winding of the exciter device.

Abstract: Damping of supersynchronous oscillations in an ac power system is accomplished by a damping circuit connected between a power line and a system neutral potential. The damping means includes a tuned circuit having a resonant frequency above the system operating frequency. Preferably, the tuned circuit further has an antiresonant frequency at the system frequency. The supersynchronous damping circuit in accordance with the invention can be used with subsynchronous damping circuits known in the prior art to enhance the damping of oscillations in the ac power system.

Abstract: The present invention relates to an automatic device for depressing low frequency oscillation of power system. It consists of an electronic circuit incorporated in the original excitation regulator of a synchronous generator. This circuit can turn the input deviation of voltage .DELTA.V into simulating state variable deviations of angular frequency .DELTA..omega., of power .DELTA.P and of power angle .DELTA..delta., and then outputs the sum of them according to the principle of optimal control. With the device of the present invention, the output capability of a remote power station may double, a whole set of measurement and feedback devices may be spared and the distortions in measurement may be avoided. The present device has further advantages of being small in size, cheap in cost, easy to establish and high in reliability.

Abstract: A synchronous machine with alternating-current exciter, wherein the stator of the exciter machine, the rotor of which runs in the opposite direction of rotation to that of the stator field, is fed from a three-phase power controller. The voltages induced in the rotor of the alternating-current machine are rectified by diodes in a three-phase star circuit. In order to minimize the effect of the voltage peaks originating from the hole-storage effect during the commutation of the diodes, which peaks are abnormally high as a result of the mutual interaction of the harmonics, there is produced a parallel path for high-frequency currents in the form of a protection circuit having low-pass characteristic so that the mutual interaction between stator and rotor harmonics if greatly reduced. Because of the risk of self-excitation, the elements of the protection circuit are matched to the machine and cause as few additional losses as possible.

Abstract: A control apparatus for controlling the power supply to the field coil of a charging generator in which a smoothing capacitor of a low capacitance value is provided to prevent maloperation in the control circuit due to ripples in the output of the generator. A switching transistor controls the current flow through the field coil, while a control transistor controls the switching transistor and a zener diode is provided for energizing the control transistor. A first detection circuit is connected to the smoothing capacitor for detecting the rectified output of the generator and thereby producing a voltage at a first detection point. A second detection circuit produces a voltage at a second detection point which is higher than the first detection point voltage. An amplifying transistor having a base connected to the first detection point energizes the zener diode in accordance with the state of the output of either of the first and second detection circuits.

Abstract: Subsynchronous oscillations in a polyphase power network can be effectively damped with a switching arrangement having a thyristor-switched regulation and a phase shifting polyphase power system. The arrangement is controllable and is periodic in nature, being responsive to a measurement signal representing a physical parameter of the subsynchronous oscillations. This signal preferably represents the difference between the instantaneous rotational frequency of the generator and a set-point value for that frequency. Control windings are connected in series with the power-network-side polyphase windings of a block transformer. Voltages induced in these control windings are phase shifted with respect to the voltages in the respective associated power-network-side polyphase windings of the block transformer. These voltages in the control windings produce a very effective damping torque on the generator, to damp out the subsynchronous oscillations.

Abstract: The present invention is directed to an automatic voltage regulating system for an electric generator comprising a detection coil for detecting the output voltage of an AC generator. The voltage regulating system includes a detection circuit comprising a rectifying circuit for rectifying the output voltage of the detection coil, a smoothing circuit coupled to the detection circuit for smoothing the output voltage and a regulating circuit coupled to the output of the smoothing circuit for shifting the voltage load thereof, wherein the regulating circuit shifts the level of the voltage in the smoothing circuit by comparing the voltage in the rectifying circuit with the predetermined voltage to control the field current during the period of the shifting of the voltage level.

Abstract: A battery charging control system for automobile, wherein a voltage regulator for regulating the output voltage of an AC generator for charging the automobile battery is controlled by detecting changes of the output voltage. When the output voltage of the generator changing with ripples is reduced with an increase of load current, the minimum value of the output voltage is detected, while when the output voltage increases with an increase of the generator rotational speed, an average value of the output voltage is detected. In accordance with these values, the voltage regulator is controlled to compensate for the changes of the output voltage of the generator.

Abstract: A rotary converter machine which includes a stator with three-phase primary, and secondary windings, and a rotor mounted within the stator which includes a damping winding. The primary and secondary stator windings are arranged on a common stator pack and located in continuous stator slots, both windings extending over the whole axial length of the common stator pack. The converter machine provides a direct transfer of the electrical energy by flux linkage between the two windings. The rotor is driven by the rotating magnetic field either asynchronously, if a drum rotor is provided, or synchronously, if a salient-pole rotor is provided.

Abstract: A supervisory unit for detecting abnormalities in shaft voltage of rotary electrical machinery and apparatus such as brushless synchronous machines. The supervisory unit includes a first detector for detecting the voltage across at least two points of the rotor shaft, a second detector for detecting the voltage between the rotor shaft and ground, and a third detector for detecting an electrical condition of an AC exciter which constitutes part of the field system of the apparatus. The third detector may detect electrical signals indicative of the field system voltage or the field system current. The supervisory unit includes a voltage comparator and a frequency comparator which receive detection signals from the three detectors to provide a signal indicating abnormality when an abnormal condition occurs, such as contact failure of a grounding brush or a failure in coil insulation.

Abstract: Signal conditioning apparatus for reducing the noise frequencies of a speed sensing means signal being fed into a compensating means for compensating the output of a synchronous generator for the effect of torsional oscillation between masses in the main AC generator system. The signal conditioning apparatus includes two speed sensing transducers mounted 180.degree. apart on opposite sides of a tooth gear wheel and summing the two FM output signals from the transducers to eliminate odd harmonics of the synchronous frequency in FM noise due to eccentricity. The preferred embodiment of the invention reduces the remaining noise from the sensed speed signal by the use of a three-pole Butterworth low-pass filter in combination with a notch filter tuned to the turbine-generator synchronous frequency to thereby reduce the unwanted noise to a large degree while providing a minimal phase shift to the sensed speed signal.

Abstract: Subsynchronous oscillations and DC offset in an electrical power system are dampened by measuring the half-cycle period of current or voltage line waves, comparing the measured half-cycle time periods to a desired half-cycle time period and dissipating the line waves in measured half-cycle time periods which are longer than the desired half-cycle time period. Damping apparatus includes a reactance connected in a power line with selectively bidirectional conductors in parallel with the reactance whereby the reactance can be shorted. Alternatively, the selectively bi-directional conductors can connect a power line to ground or neutral when half-cycle time periods exceed a desired half-cycle time period.

Abstract: The laminated stator core for an engine ignition system includes in addition to that ignition system an arrangement for charging the storage battery of an internal combustion engine powered device during engine operation with a charging coil surrounding one leg of the ignition stator core, a capacitor in parallel with the coil, and a rectifier coupled to the charging coil for conveying a varying unidirectional current to the battery. The ignition system may be of the type having a three legged E-shaped laminated stator core and a flywheel supported permanent magnet with charging coils being positioned on each of the outer E legs with diodes in series with each charging coil and means connecting the two coil-diode series circuits in parallel with one another and to the battery for providing a pair of sequential primary charging current pulses to the battery during each revolution of the flywheel. A fourth laminated stator core leg supporting a charging coil may be employed in some circumstances.

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: A circuit for damping hunting oscillations of controlled electric machines. The circuit is provided with a measuring circuit for determining the hunting oscillations and an identifier circuit for determining the angle components of such hunting oscillations. A phase shifter circuit is provided for receiving the angle components produced by the identifier circuit and forming a hunting oscillation correction signal which is shifted in phase from the hunting oscillations by a predetermined phase angle. The hunting oscillation correction signal is conducted to a control unit of the electric machine. The invention is particularly useful in damping hunting by the rotors of voltage controlled synchronous generators.

Abstract: A voltage source is connected in series with the neutral secondary winding on a generator step-up transformer through an electrical reactance. A control circuit and a pair of thyristor banks are employed to apply the voltage source to the transformer winding to dampen sybsynchronous resonance currents and to prevent torsional mode vibrations from occurring within the generator.