Car altanator rewind?

Question

is it possible to change the stator windings on a car altanator to make a sqare wave output,would the rotor field poles have to be a diferent shape as well.

Answer 1

Nope.  Turning sine waves into square waves requires a lot of fiddling, not something you are going to be able to do with an alternator

Answer 2

No, its the rectifier that controls the output type.