Nikola Tesla Books
ONE-HALF KILOWATT TRANSFORMER OUTFIT 87 Diam at 60~ Primary data For 110 volts 25~ * 462 turns 14 D.C.C 600 237 turns #14 D.C.C. 125~ + 125 turns 14 D.C.C D.C.C. For 220 volts use twice as many of $170.c.c. Fig. 3. Data for primary winding Primary Winding.-Fig. 3 gives the data for the pri mary winding to use for any of the commercial frequencies. The core is so generously proportioned and the quality of iron specified so good that the only change necessary for use on various frequencies is in the number of turns of wire. The primary is wound upon the form illustrated in Fig. 5. If the builder has a lathe, the form may well be mounted upon an arbor or even upon the faceplate. The No. 14 D.C.C. wire is wound upon a base of several layers of oiled paper 2½ in. wide. In preparing the form for the winding, a layer of cord is first wound over the wooden drum, and the base of oiled paper placed over this layer of cord. The object of the cord is, of course, to permit the winding to be removed by pulling out the cord. Between each layer of wire and its neighbor, four turns of the oiled paper should be taken. This will make the
