. Practical wireless telegraphy; a complete text book for students of radio communication . connections to the power mains, the aerial changeoverswitch and the telegraph key. This set was designed with the utmost simplicity of construction and operation in viewand is one that can be placed in unskilled hands without fear of breakdown. Unlike the Marconi transmitters previously described, type P-9 is not fitted with avariable field resistance or an aerial ammeter. Fixed resistance coils are connected in serieswith both the motor and generator field windings and conditions of resonance between t
. Practical wireless telegraphy; a complete text book for students of radio communication . connections to the power mains, the aerial changeoverswitch and the telegraph key. This set was designed with the utmost simplicity of construction and operation in viewand is one that can be placed in unskilled hands without fear of breakdown. Unlike the Marconi transmitters previously described, type P-9 is not fitted with avariable field resistance or an aerial ammeter. Fixed resistance coils are connected in serieswith both the motor and generator field windings and conditions of resonance between the STANDARD MARINE SETS OF AMERICAN MARCONI CO. 249 open and closed oscillalion circuits are determined by a small glow lamp shunted by a semi-loop of wire. It is to be observed also that the coupling between the primary and secondarywindings is changed by moving the primary at right angles to the secondary. (a) Description of the Set. The motor generator is a >^ K. W. 500 cycle machine of theCrocker-Wheeler type, the load voltage of the alternator being about 120 volts. SWITCH ^~-^B. Fig. 266b—The Marconi A K. W. Cargo Type Transmitting Set Complete. Tne motor has a differential field winding for maintaining a constant speed under variableload and it is designed for connection to a 110 volt direct current circuit. _ The motor starter is one of the Industrial Controller Companys hand-operated type withthe usual connections to the motor. (See wiring diagram, Fig. 266-d.) • _ _ Protective V. microfarad condensers are attached to the motor S^^rator circmts toneutralize any differences of potential that may be set up by the ^^^^..^X^^Zxtof these condensers is connected to a binding post of the machine and the other termmal tothe frame of the motor generator, which, in turn, is thoroughly connected to earth _ _ The high voltage transformer is one of the closed core type (Fig. 266b), which is im- 250 PRACTICAL WIRELESS TELEGRAPHY. mersed in a semi-liquid grease. A small fixed
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
