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
s later described. Figs. 353 and 354 show two forms of disc stamped in one piece. Thefirst illustrates a solid disc, and the second a ventilated disc in whichmore or less of the metal is cut away near the center, thus providingpassages for the circulation of air which carries away some of the…
Electrical engineering
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