Asynchronous motor with the similarities and differences in the structure?

Commonly used transitions type (i.e.,rotating magnetic pole type) of synchronous motor and induction magnet prices motor stator structure identical, the rotor structure difference between large non-salient pole type and salient pole synchronous motor rotor and stator rotor type two kinds, the rotor field winding ac motor wind generator through the brush and slip ring plus dc excitation has a squirrel-cage asynchronous motor rotor and winding type two kinds. Rotor loop of its conductor induced potential and current.