Difference between induction motor and synchrous motors?

Induction generators consist of stator windings and rotor windings both of which can be excited or one can be excited at a time so that they can run as singly excited as well as doubly excited machines .and in induction machines rotor consists of ARMATURE winding which is moving and the static FIELD windings is in stator.

Whereas synchronous gen. or alternators consists of static stator which consists of ARMATURE winding and moving rotor which consists of FIELD windings. so alternators are only singly excited systems in which the field winding is energised by a DC supply or with a rectifier and AC source and the or prime mover is moved with the help of steam as in thermal powerplant or with the help of water in hydropower plant so it is used in generating units where AC power is generated.