I had no idea that the reason our mains power was fixed at 50Hz was because of the speed of rotation of the turbines.,(reply>), @finbat I was speaking to the original commenter. ,(reply>), So arc lamps work better at 50Hz?,(reply>), Other way around,(reply>), I wasn't, 50Hz was chosen basically as the lowest possible without light flickering. (US chose 60Hz because arc lamps worked better).