theory of operation of synchronous motors?
In a synchronous AC motor a current is supplied onto the rotor. This then creates a magnetic field which, through magnetic interaction, links to the rotating magnetic field in the stator which in turn causes the rotor to turn. It is called synchronous because at steady state the speed of the rotor is the same as the speed of the rotating magnetic field in the stator. The alternative kind of electric motor is an induction motor, where the current in the rotor is generated by induction - similar to a transformer. Induction motors are far more common because they are simpler, but synchronous motors have certain advantages and are used in some applications.
