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 297
rcuit numbers painted thereon, or causes arrows tomove and point to the numbers of the circuits marked close tothem on the indicator panel. 2,388 HAWKINS ELECTRICITY Ques. How does the shutter drop work? Ans. It is released from closed position by the action of an electromagnet, drops by gravity,… … ^FACE. Fig. 3,279.—Shutter or gravity annunciator drop. In operation, when the circuit is com-pleted by the depression of a push center, the current flows through the coils of theelectromagnet M, and energizes its core, and the latter attracts the armature A, pivotediat B. When the armature is…
Electrical engineering
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