Automatic control for a high tension arc furnace
A 1917 engineering thesis by Glen David Bagley, submitted at the University of Illinois, on automatic control of a high-tension arc furnace. Hand-inked line diagrams show delta and star voltage triangles labelled 220 and 127, resistance-tapped conductors, and a full wiring schematic with transformer, contactors and motor, offering thin-stroke technical drawing and handwritten numerals for reuse.
