The generation of ultrasonic power with rotating machinery

A brief note on the history of high-frequency machinery is presented, followed by a general discussion of some of the salient characteristics and present-day capabilities of highfrequency rotating machinery. Specific reference is made to a 1.5-kw, 21.4-kc motor generator set. Discussion includes comments on the physical and electrical characteristics of the machine performance curves of output voltage regulation and efficiency are presented. Over-all motor generator efficiencies of 55% have been achieved at a 21.4-kc output frequency. Finally, some of the considerations r matching of the motor-generator to the transducer load are discussed.