Twentieth century hand-book for steam engineers and electricians, with questions and answers .. . FIGURE 75. In Fig. 75 is shown the principle upon which thetransformer used in alternating current work are opera-ted. Two separate coils of wire are wound on a ring ELECTRICITY FOR ENGINEERS LSI of laminated iron. One of the coils contains a num-ber of turns of fine wire, while the other contains onlya few turns of large wire. When an alternating cur-rent is sent around the coils of fine wire, generallycalled the primary, a current will be induced in thecoil of heavy wire, or secondary. The amoun
Twentieth century hand-book for steam engineers and electricians, with questions and answers .. . FIGURE 75. In Fig. 75 is shown the principle upon which thetransformer used in alternating current work are opera-ted. Two separate coils of wire are wound on a ring ELECTRICITY FOR ENGINEERS LSI of laminated iron. One of the coils contains a num-ber of turns of fine wire, while the other contains onlya few turns of large wire. When an alternating cur-rent is sent around the coils of fine wire, generallycalled the primary, a current will be induced in thecoil of heavy wire, or secondary. The amount of cur-rent induced in the larger wire will be relativelygreater in amperes and less in potential than that ofthe fine wire circuit. This ratio is almost entirelydependent upon the relative number of turns existing. FIGURE 76. between the large and the small wires. To illustrate,suppose we had a current of 10 amperes at a pressureof 1,000 volts in the primary, and there were ten timesas many turns of wire in the primary coil as in thesecondary, then we would get a current of ioo amperesat a pressure of ioo volts in the secondary coil. Thissame relation would hold true whatever the ratiobetween the number of turns on the two coils mightbe. In Fig. 76 is shown a core of iron having on oneend a primary coil connected to a battery. On theother end of the core is another coil connected to the 132 ELECTRICITY FOR ENGINEERS ends of which is an incandescent lamp. By makingand breaking the battery circuit the lamp may be madeto flash up, due to the great voltage induced in thesecondary coil. This is a good thing to rememberwhen working with a dynamo or motor. Do notquickly break the shunt field connection, as theincreased voltage due to the current induced by thefield magnet when the circuit is broken is
Size: 2106px × 1186px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpu, booksubjectsteamturbines
