Controls for Step Voltage Regulators [includes discussion]
T. C. Lennox · Transactions of the American Institute of Electrical Engineers Part III Power Apparatus and Systems · 1955
A unique control circuit for step voltage regulators is described. An auxiliary relay with four pairs of contacts has been eliminated; this results in reduced maintenance and quiet operation. Full integrating time delay is obtained by means of a motor-driven time-delay relay operated directly by the contacts of the voltage-regulating relay. Sparking on the voltage-regulating relay contacts is reduced to a minimum.