Abstract: A permanent magnet alternator is connected directly across the battery through a full-wave bridge rectifier. The bridge includes a pair of controlled rectifiers which are selectively rendered conductive to charge the battery through the bridge when the battery voltage drops below a preset value. A Zener diode and one transistor monitor the battery voltage and control a second transistor which in turn controls gating current from the alternator to the controlled rectifiers.

Abstract: A high capacity storage battery is mounted in a vehicle, and is selectively charged by the alternator thereof to afford a power source for remote utilization devices. Voltages of the standard automobile battery and the high capacity battery are monitored, and are charged by the alternator in accordance with a fixed priority. When the automobile battery is less than fully charged, it is charged by the alternator irrespective of the voltage at the high capacity battery. When the automobile battery is full, the high capacity storage battery is charged by the alternator until it is fully charged. Thereafter, the alternator is decoupled from both such batteries.

Abstract: A brushless tachometer utilizing four stator windings and series connected field effect transistor commutation switches to provide an input to a summing amplifier. Connection of the field effect transistor switches to the summing junction of the amplifier and use of series resistance and back-to-back clamping diodes on the winding side of the field effect transistors permits commutation switching with a minimum of transient voltage changes due to interruption of the stator winding current.

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.