Discussion at swampscott meeting: Tap changing under load: Voltage control obtained by varying transformer ratio: Changing transformer ratios without interrupting the load

Swampscott, Mass., May 7, 1925 B. G. Jamieson: On the system of the Edison Company in Chicago, there has been built up within the last four years, a 33,000-volt nominal voltage, 60-cycle system of about 360,000 kilowatts. The transformers were generally equipped with the tap changing system described, the earlier forms with the double winding, and in other cases, a system which involves the step switching scheme with a connected reactor giving the same effect that the last author described.