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 553
four. It is an im-proved type of polyphase relay. reason the lever movement is divided into two parts: 1, the move-ment which causes the closing of the operating circuit, and 2,the movement which causes the interlocking of other levers. The first important step toward the development of a… … TRAIN
Electrical engineering
Internet Archive · Brigham Young University · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer03inte-251-144.webp)
