Synchronous machine field windings —not as simple as they look

摘要

Deceptively simple in appearance, seemingly much more ragged in construction than the elaborately shaped coils of an a-c stator, the rotating pole windings of a synchronous motor field actually embody many complexities, mechanically and electrically. What we will consider here is the so-called salient-pole design, in which a circle of laminated pole assemblies (Figures 1 and 2) is mounted around the periphery of a spider/shaft assembly of either laminated or solid steel construction. (Solid-pole rotors, as in large turbine generators, are beyond the scope of this article.)