Journal of the Institution of Electrical Engineers, Part 1, General · 1946 · 16 citations · 0 references
The paper reviews alternators capable of up to 50 kHz and identifies the modern heteropolar inductor alternator as the most suitable for most applications. It examines the electrical and mechanical design of heteropolar inductor alternators, their use in metal melting and steel surface hardening, and provides a brief mathematical treatment of their novel features. The heteropolar inductor alternator outperforms older homopolar and heteropolar types by reducing armature conductors for 400–3,600 Hz and, at frequencies above 3,600 Hz, by combining windings with stator slotting to greatly decrease the number of stator slots needed.
This paper reviews the various types of alternators available for the generation of frequencies up to 50 000 c/s, and shows that for the majority of applications the modern heteropolar inductor alternator is the most suitable machine. It demonstrates that this alternator is superior to the older homopolar and heteropolar types, owing, in the case of machines required for frequencies of 400 to 3 600 c/s, to a system of field and armature windings which substantially reduces the number of armature conductors required to generate a given e.m.f. For frequencies above 3 600 c/s this superiority is due to a combination of these windings with a stator slotting arrangement which permits, for a given frequency and speed of rotation, a large reduction in the number of wound stator slots. The electrical characteristics and mechanical construction of these alternators are discussed, together with their application to the melting of metals and surface-hardening of steel. An appendix gives a brief mathematical treatment of the theory of their novel features.