Hawkins electrical guide ... : questions, answers & illustrations : a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications ; a practical treatise (1914)
Hawkins, N. (Nehemiah), 1833-1928 · New York : T. Audel & Co. · leaf 114
Figs. 353 and 354.—Solid and ventilated core discs. In fig. 353, the metal cut away nearthe center reduces the weight and provides passages for air circulation. In some instancesa forced circulation is secured by means of a fan attached to the armature, as shown infig. 366. drying varnish that will…
Electrical engineering
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