I want to talk about induction motors and Universal motors.
1) is the rotor of an Universal Motor a Wound rotor?
2) the induction motor with Wound rotor have commutators?
3) Universal Motor can work with DC or AC current. Can an AC Universal Motor be considered an induction motor? Its stator creates a variable magnetic field that induces magnetic field on rotor.
4) how can DC Universal motor works if the magnetic field that goes from coils to the stator is constant? I think electric current creates magnetic field on the stator, and eletric current goes to the rotor by the brushes, so there will be 2 magnetic fields. But wouldn't they have same polarities? Does commutator has something to do with this?