. Practical wireless telegraphy; a complete text book for students of radio communication . ndary current causingan increase in the primary current. If, for example, current at 110volts, 500 cycles, flows throughwinding P, the flux will alternatethrough the core 1,000 times persecond, setting up 1,000 alterna-tions of current in winding S consists of a great number of turns, the voltage of the current induced inS will be very much greater than the voltage of the current in winding P. Infact, it is found that the voltage in the secondary winding is almost a directratio of the primary an
. Practical wireless telegraphy; a complete text book for students of radio communication . ndary current causingan increase in the primary current. If, for example, current at 110volts, 500 cycles, flows throughwinding P, the flux will alternatethrough the core 1,000 times persecond, setting up 1,000 alterna-tions of current in winding S consists of a great number of turns, the voltage of the current induced inS will be very much greater than the voltage of the current in winding P. Infact, it is found that the voltage in the secondary winding is almost a directratio of the primary and secondary turns, e. g., E-s T-s E-p t-pwhere T-p ^ the current in the primary;where T-s = the current in the secondary;E-p and E-s = the voltage in the primary and secondary circuits respectively. Fig. 38 shows the open core, step-up voltage, constant current transformer employedin radio work. C, the core constructed of a bundle of fine iron wires or of sheet iron is covered with several layers of Fig. 37—Magnetic Circuit of Step-up Closed CoreTransformer. —• •— 52 SECONDARY. i; \ \ I \I I insulating cloth followed by one or twolayers of coarse copper wire. An insu-lating tube (not shown) is placed overthe primary. It is made of some mate-rial which will withstand the heat andpossess the requisite insulating this tube is placed a secondarywinding which consists of severalthousand turns of fine wire wound up inthe form of pancakes as at S-1, S-2, is little magnetic reaction of thesecondary upon the primary in this typeof transformer owing to the lack of acontinuous iron path for the flux and theself-induction of the primary thereforeremains nearly constant. The transform-er will draw practically the same currentwhen the secondary is on short circuit as when it is open. The closed core transformer can be designed to liave this operating characteristic whenfitted with a magnetic leakage gap shown by the dotted line, Fig. 37. Through the leakage
Size: 2020px × 1237px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
