Cyclopedia of applied electricity : a general reference work on direct-current generators and motors, storage batteries, electrochemistry, welding, electric wiring, meters, electric lighting, electric railways, power stations, switchboards, power transmission, alternating-current machinery, telegraphy, etc. (1916)
American Technical Society · Chicago : American Technical Society · leaf 191
at the energy foroperating the unit switches is supplied by means of compressed air in-stead of the electric current. This involves many differences in detail.The compressed air is controlled by electro-pneumatic valves,current for these being supplied through a train line as in the previouscase.… … Fig. 67. Cross-Section of Westinghouse UnitSwitch Fig. 68. View of Westinghouse UnitSwitch means of a multiple-wire control circuit (as in the Sprague-General Electriccontrol). (2) A train line and set of control circuits, with a master controllerby means of which the operating coils of the…
Electrical engineering
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