In this paper we describe some of the design and operating characteristics of an unusual S-kW 25-kHz transistorized inverter-converter, in which the high-power switch consists of a series arrangement of low-power transistors. The dc voltage is obtained from the three-phase line by voltage tripling rectification in each phase, thus avoiding a 60-Hz transformer. The resulting supply is exceptionally compact, light weight, and inexpensive. In contrast to most solid-state circuits, this supply is found to be extremely resistant to reactive voltage “spikes” attendant to the excitation of inductive loads. We also discuss the advantage in reliability resulting from the series arrangement of the transistors. Copyright © 1972 by The Institute of Electrical and Electronics Engineers, Inc.