. A textbook on the locomotive and the air brake . , depending on the hardness of the brushes. The brushesshould fit the commutator perfectly; if the fit is poor, or if thebrushes do not make good contact with the commutator, theywill spark badly. To fit new brushes to the commutator, takea strip of No. 0 sandpaper about \^ inches wide, slip it betweenthe commutator and brush with its rough side toward the brush, §14 THE HEADLIGHT. 11 and then move it to and fro, as shown in Fig. 5, until the brushhas been ground to a proper curvature. If you find the commutator is running dark and h
. A textbook on the locomotive and the air brake . , depending on the hardness of the brushes. The brushesshould fit the commutator perfectly; if the fit is poor, or if thebrushes do not make good contact with the commutator, theywill spark badly. To fit new brushes to the commutator, takea strip of No. 0 sandpaper about \^ inches wide, slip it betweenthe commutator and brush with its rough side toward the brush, §14 THE HEADLIGHT. 11 and then move it to and fro, as shown in Fig. 5, until the brushhas been ground to a proper curvature. If you find the commutator is running dark and has theappearance of being rough, it should be cleaned. To cleanit properly, remove the brushes, tack a piece of No. 0 sandpaper. on a board of the proper size, start the dynamo running andthen work the sandpapered board as you would a file, holding itlevel on the moving commutator. Do not attempt to just usethe paper itself or to hold the paper with the fingers, as thistreatment will probably do more harm than good. Crocuscloth may be substituted for No. 0 sandpaper, but in no casemust emery cloth or a file be used. If the conunutator becomesvery rough or out of true, it should be trued up in a lathe, usinga sharp tool and taking very light cuts. 12 THE ELECTRIC HEADLIGHT. § 14 After turning a commutator down, polish it with truing or cleaning a commutator, care should be taken tosee that tlie sections of the commutator are not connected by aburr or a piece of metal reaching across the strips of mica thatseparate the sections. The mica should be kept just a triflebelow the surface. If allowed to project slightly, it will causethe brushes to vibrate so as to produce sparking. A commonthree-corne
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectrailroa, bookyear1901
