. St. Nicholas [serial] . FIG. 19. VARIOUS STYLES OF ELECTRO-MAGNETS. For electric bells, telegraph-sounders, andother electrical equipment requiring the horse-shoe or double magnet several kinds can beused, but the simplest is made from two car-riage- or machine-bolts and a yoke of soft iron,as shown at E in Fig. 19. The yoke is $/% of aninch in width, 2^ inches long, and provided withtwo ^4-inch holes i1^ inches apart from centerto center. Two-inch carriage- or machine-boltsare used, and they should be ^ of an inch indiameter; nuts are screwed on far enough toadmit the yoke and another nut t
. St. Nicholas [serial] . FIG. 19. VARIOUS STYLES OF ELECTRO-MAGNETS. For electric bells, telegraph-sounders, andother electrical equipment requiring the horse-shoe or double magnet several kinds can beused, but the simplest is made from two car-riage- or machine-bolts and a yoke of soft iron,as shown at E in Fig. 19. The yoke is $/% of aninch in width, 2^ inches long, and provided withtwo ^4-inch holes i1^ inches apart from centerto center. Two-inch carriage- or machine-boltsare used, and they should be ^ of an inch indiameter; nuts are screwed on far enough toadmit the yoke and another nut to hold it inplace, and bind the three pieces in one compactmass. Washers are placed on the bolts to hold. FIG. DEVICE. the ends of the wire coils in place, and the wind-ing may be done on each bolt separately and con-nected to the yokeafter the winding iscompleted. Doublecotton insulated No. 20 or 22copper wire should be usedfor the coils. Be careful towind the wire in opposite di-rections on the two cores; orif wound the same way, con-nect thorn up so that the current will pass throughthem in opposite directions. In winding magnets it will often be foundconvenient to slip the spool over a spindle con-nected with a crank. Such an apparatus, whichis to be held in a vise, is shown in Fig. thick part of the shank is held looselyagainst the block by a pair of ordinary staples. THE INDUCTION-COIL. A simple induction-coil is made by windingtwo coils of wire on a spool through which, asa core, there is a ^-inch iron bolt, the wholeapparatus being about six inches long. Firstwind three layers of No. 24. cotton-insulatedwire, leaving about six inches of the wire pro-jecting from
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Keywords: ., bookauthordodgemar, bookcentury1800, bookdecade1870, bookyear1873
