Sunday, May 8, 2016
SYNCHRONOUS: means "turns at a speed proportional to applied frequency independent of load".
For this to occur, the magnetic field on the rotor must be powered separately from the stator magnetic field. As Hector pointed out - the rotor field may result from permanent (e.g. rare earth) magnets, or from an electromagnet.
If the rotor field is electrically created, the current has to come from somewhere. One way to do this is to use a separate DC supply and supply power th ...