1. The problem statement, all variables and given/known data Is there no residual magnetism in case of synchronous machines? Actually I had this doubt because of the OCC of alternator as when the field current is zero the generated value of the machine is also zero unlike the dc machines..why is it so?? 2. Relevant equations 3. The attempt at a solution The OCC of a synchronous machine is plotted between the generated emf and field current ast rated speed .