Transactions section: Preprint of corresponding pages from the current annual AIEE transactions volume: Pentode ignitrons for electronic power converters

THE history and development of suitable electronic tubes and circuits for high-voltage power-conversion systems is discussed in a companion paper.¹ Briefly, the first power unit after laboratory tests consisted of a 40–60-cycle 5,000-kw power converter. The tubes for this unit were of the thyratron^∗ type. The nonsynchronous link operated at a direct potential of 30,000 volts and a current of approximately 170 amperes. Power from the 40-cycle system was converted to direct current through 12 phano-tron tubes connected in a cascade arrangement of two three-phase double-way rectifier circuits. The direct current was converted to 60-cycle a-c power through 12 thyratrons connected in a similar arrangement of double-way inverter circuits. Initial operation was remarkably free from any basic trouble. Operation over a period of some five years demonstrated the complete practicability of sealed electronic tubes for this type of service.