I understand three-phase motors and how the phase offset could produce a rotating magnetic field and a torque. But what about single-phase induction motors? I don't understand how they would be constructed at all. I know that a single-phase induction motor won't self start, but I don't know how it would be setup to work at all. On a simple two pole motor, if both poles are fed from a 120V 60 Hz sinewave, wouldn't both be the same polarity at the same time? Can anyone explain how it works? Slightly unrelated, but do all inductors impart a 90 degree phase shift? All they are is a coil of wire, correct? Does a 30 turn not shift more than a 1 turn coil?