Ac Generators or Alternators
Basic Principle Ac generators or alternators operate on the principles of electromagnetic induction. There is one important difference between A.C generator and D.C generator the armature rotates and the field system is stationary where as in A.C generator it is just the reverse of it.In their case standard construction consists of armature winding mounted on a stationary element called stator and field winding on a rotating element called rotor. Speed and Frequency In an alternator there exists a definite relationship between the rotational speed (N) of the rotor the frequency (f) of the generated e.m.f and the number of poles P. P= 120f / N It is clear from the above equation that because of slow relative speeds of engine driven alternators their number of poles is must greater as compared to that of the turbo generators which run at very high ...