ABSTRACT
All conventional machines rely upon magnetic fields for the purpose of energy conversion. Windings are arranged on the periphery of a stationary member (stator) and a rotating member (rotor) so as to set up a field distribution of magnetic flux density in the space which separates them (air gap). A valid approach to the study of electric machines is to deal directly with the electromagnetic fields. Knowledge of the field distribution leads to a deeper understanding of where flux is concentrated, where currents flow, where forces appear, and where heat is generated within the machine. It is useful to begin a study of winding distribution by considering what is generally termed a doubly cylindrical machine. It is important to note that harmonic elimination is not without its penalties. Large, low-speed hydroelectric generators may have as many as 60 or more poles while high-speed steam turbine-generators are wound with only two or at most four poles.
