. Practical wireless telegraphy; a complete text book for students of radio communication . 112 PRACTICAL WIRELESS TELEGRAPHY. greatly impede the radio-frequency oscillations. Hence the secondary winding is protectedfrom injury. 108. High Voltage Transformers.—The construction of the open andclosed core types of transformers of the Marconi Company is shown in Figs. 131and 132. The primary coil of the open core transformer is wound on a core consisting o£a bundle of fine iron wires bound in circular form. The core is covered with. CONDENSES . Fig. 130—High Frequency Choking Coils. several* laye
. Practical wireless telegraphy; a complete text book for students of radio communication . 112 PRACTICAL WIRELESS TELEGRAPHY. greatly impede the radio-frequency oscillations. Hence the secondary winding is protectedfrom injury. 108. High Voltage Transformers.—The construction of the open andclosed core types of transformers of the Marconi Company is shown in Figs. 131and 132. The primary coil of the open core transformer is wound on a core consisting o£a bundle of fine iron wires bound in circular form. The core is covered with. CONDENSES . Fig. 130—High Frequency Choking Coils. several* layers of insulating tape followed by two or three layers of rather coarsecopper wire, such as No. 10 or No. 12 S. C. C. The entire primary is then in-serted in an insulating tube. The secondary winding is composed of several sec-tions, each consisting of a number of thin pancakes wound with rather fine wire,such as No. 26 to No. 32. Dry insulation is employed and in the larger sizes a blast of air is blownthrough the primary core to keep the transformer cool. The open core transform-ers are designed for primarypotentials from 110 to 500volts and for frequencies from60 to 500 cycles. The sec-ondary potential rarely ex-ceeds 15,000 volts. The transformer shown inFig. 131 is one of the open-core type supplied with the2 K. W. transmitters of theAmerican Marconi primary core and wind-ing are inserted in a Micartainsulating tube, but the sec-ondary turns are split intogroups, each consisting ofseveral small pancakes
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
