Date of Award

Summer 1979

Degree Type

Master's Essay - Restricted

Degree Name

Master of Science (MS)


Electrical and Computer Engineering


With the advent of the Silicon Controlled Rectifier and other members of the thyristor family like the triac, a whole new technology was born in the control of electric motors. Accurate and economical control was made possible for motors of all sizes, from small machine tools to large industrial drives. This essay looks into some of the more popular forms of thyristor control circuits in use today, including the highly sophisticated phasecontrolled cycloconverter.