His Theory of Alternating-Current Machines (first published in the 1930s/40s, with a famous second edition in 1951) was revolutionary. It bridged the gap between the graphical methods of the early 20th century and the complex vector algebra that would dominate the late 20th century.
Explains how balanced three-phase currents in stator windings (displaced by 120∘120 raised to the composed with power Theory-alternating-current-machines-alexander-langsdorf-pdf
: The chapters on synchronous generators and motors are legendary for their depth in armature reaction and voltage regulation. Theory-alternating-current-machines-alexander-langsdorf-pdf