Tesla Notes 07: Pittsburgh and the Question of Sixty Cycles
Westinghouse's alternators gave 133 periods a second and my motor wanted far fewer. I spent a year between two numbers.
Why 60 Hz? Tesla's Pittsburgh year worked out: motor speed n = 120f/p, split-phase motors, lamp flicker and filament heat, and transformer iron versus frequency.
Nikola Tesla
November 5, 2026
23 min