Electricians' operating and testing manual; a hand book for men in charge of electrical apparatus, repair men, trouble men, lamp trimmers, and electricians generally (1916)
Horstmann, Henry Charles, Tousley, Victor Hugo, 1875- joint author · Chicago, F.J. Drake & co · leaf 247
are Cooper-Hewitt Lamp 241 ■must be exercised that the lamp is connected properlywith reference to polarities. Current passing throughit in the wrong direction will quickly ruin the lamp.The circuit can readily be traced in the figure. Whenthe main switch is closed and before the lamps aretilted… … Figure 149 path through the small resistance in parallel wdth thelamp. Should one lamp fail to work, the currentthrough the magnet would cease and the armature fallthus closing the circuit so that the other lamps mayremain in use. The main switch should never be leftclosed while the lamps are not…
Electrical engineering · Electric testing
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer03inte-192-112.webp)