. Motion picture electricity. a transformer having considerablemagnetic leakage because the primary and secondary coilsare some distance apart and are mounted on separate legsof the iron core. When the line current passes throughthe primary coil it generates magnetism in the iron coreand the current being alternating this magnetism is re-versed a given number of times per second, dependingupon the frequency of the current. If the secondary coilis not connected to any load, the magnetism will passthrough the iron as indicated by the arrows, first in onedirection, then when the current reverses
. Motion picture electricity. a transformer having considerablemagnetic leakage because the primary and secondary coilsare some distance apart and are mounted on separate legsof the iron core. When the line current passes throughthe primary coil it generates magnetism in the iron coreand the current being alternating this magnetism is re-versed a given number of times per second, dependingupon the frequency of the current. If the secondary coilis not connected to any load, the magnetism will passthrough the iron as indicated by the arrows, first in onedirection, then when the current reverses in the other 52 MOTION PICTURE ELECTRICITY direction performing no work, simply keeping the ironcore excited, and the secondary coil under tension. If we should now put load on the secondary coil as indi-cated by the arc lamp in Fig. 21, all of the magnetism willno longer pass through the core leg upon which the sec-ondary coil is mounted, but some of the magnetic linesof force will crowd over the air gap between the primary. Fig. 21 and secondary coils and these lines are therefore lost andare of no use in producing voltage in the secondary coil,allowing the voltage in the secondary to drop when thearc lamp is turned on. Therefore, you can understand that a transformerbuilt as illustrated in Figs. 20 and 21 is a very poor con-stant potential transformer, in fact it would not do at all,unless a given number of lamps were always burning atthe same time, because the voltage would fluctuate upand down as the number of lamps were decreased orincreased. CONSTANT POTENTIAL WINDINGS In view of the foregoing it becomes necessary to placethe primary and secondary coils of a constant potentialtransformer very close together and, as a matter of fact,modern transformers are built in sections with the pri-mary and secondary windings sandwiched between eachother and in some instances the windings are one on top MOTION PICTURE ELECTRICITY 53 of the other as illustrated in Figs. 22 and 23, in
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Keywords: ., bo, bookcentury1900, bookdecade1910, bookidmotionpictureele00hall
