Abstract: The laminating 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: For damping torsional oscillations of an electric a.c. generator, a speed-sensing member, for example a tachometer-generator, is connected to the a.c. generator. The speed-dependent signal generated by the speed-sensing member is supplied to a band-pass filter which is adapted to the natural frequency of the torsional oscillations. The output signal of the band pass filter is supplied directly to the control angle determining means of a converter connected to the generator. In this way, the power of the converter is modulated in such a way that the oscillations are damped.

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: Being proposed is a circuit for association with the regulator of an electrical generator, especially an AC generator, and serving to smooth the voltage supplied by the electric generator. The circuit includes a compensation device consisting of at least one active semiconductor switching element, usually a transistor, and so connected to the regulator input as a supplement thereto that the generator output voltage is smoothed by a compensation voltage whose own ripple or oscillatory component is in opposite phase to the generator voltage.In particular, the compensation circuit includes a voltage divider connected to the generator output voltage and having a tap which is connected via a capacitor to the control electrode of the transistor whose main conducting path is connected in parallel to a further voltage divider joined to receive the generator voltage as well as to supply the input voltage to the regulator.

Abstract: A shaft torsional oscillation signal of a rotatable torsional system including a rotor of a synchronous machine, at least one rotatable body and a shaft coupling the synchronous machine and the rotatable body, is detected. The shaft torsional oscillation signal with a specific frequency is made to advance the phase thereof by a stabilizing control device. The field voltage of the synchronous machine is so controlled that a sub-synchronous resonance (SSR) of the rotatable torsional system caused by the specific frequency is restrictedly controlled by the shaft torsional signal of the specific frequency phase-advanced.

Abstract: A dynamic stabilizer of the type which is utilized to compensate or stabilize the effect of subsynchronous resonance oscillations in a turbine generator system is taught. Silicon controlled rectifiers are connected in series with inductors between the lines of the electrical system. The silicon controlled rectifiers may be maintained at two quiescent conduction intervals of 90.degree. and 135.degree. depending upon the peak value of rotor oscillation. If the peak value of rotor oscillation is sufficiently small the lower conduction interval of 90.degree. is utilized as this is sufficient to stabilize low level oscillations. Furthermore, it has great advantage in the fact that the losses represented by 90.degree. quiescent conduction interval are relatively small when compared with the larger quiescent conduction interval.

Abstract: Apparatus is described for monitoring arcing of brushes used in the transfer of current signals to and from the field of a generator. Electrical signals from the brushes, which are applied to the disclosed monitor for analysis, may include brush arcing signals to be monitored and in addition high-amplitude noise spikes in the same frequency band as the brush arcing signals, the noise spikes thus masking accurate detection of low level brush arcing by conventional devices. A two-stage clipping network is provided in the monitor to raise the brush arcing/noise ratio and thus mitigate the masking effect of the noise spikes without loss of a portion of sampling interval during which arcing may occur.

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 three-phase permanent magnet alternator is disclosed employing a fractional pitch stator winding of about two-thirds or 120 electrical degrees for minimizing third harmonic circulating current in the phase windings. The alternator has a rotor supporting permanent magnet poles and a slotted stator having coils disposed in the slots with the pitch of each coil being less than the rotor pole pitch and the coils of each phase connected in series to form a fractional pitch phase winding. The rotor circumscribes the stator and the permanent magnet poles have an arcuate extent nearly as great as the rotor pole pitch.

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: 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.