. Practical wireless telegraphy; a complete text book for students of radio communication . ries winding, the current which flowsin it increasing with the load and causing the pressure to rise. The number of turns of eachwinding and the relative strength of current is proportioned so that a practically constantpressure is maintained under varying load. Initial adjustments of the voltage can of coursebe secured by means of a field rheostat such as shown at R-1. The student should note carefully that current must circulate in both the ELECTROMAGNETIC INDUCTION. 29 series and shunt windings in th
. Practical wireless telegraphy; a complete text book for students of radio communication . ries winding, the current which flowsin it increasing with the load and causing the pressure to rise. The number of turns of eachwinding and the relative strength of current is proportioned so that a practically constantpressure is maintained under varying load. Initial adjustments of the voltage can of coursebe secured by means of a field rheostat such as shown at R-1. The student should note carefully that current must circulate in both the ELECTROMAGNETIC INDUCTION. 29 series and shunt windings in the same general direction in order that the re-sultant magnetic fields may have the same general direction. 33. The Electric- Motor.—A motor is a machine for converting electricalenergy into mechanical energy. There is essentially no difference between amotor and a dynamo. Any dynamo connected to a source of electric power willrun as a motor and any motor driven by mechanical power such as a steamengine, etc., will generate a current of electricity. The differences between the RHEOSTAT. TO-LOAD two machines are mainly fundamental operating principle ofthe motor is as follows: A wire carryinga current placed in a magnetic field willtend to move in a direction at right angles both to the direction of the field and to thedirection of the current. For example, ifthe plane of a given coil of wire lying be-tween the poles of a magnet is parallel toa magnetic field, and a current is passedthrough the coil, it will tend to turn orto take up a position at a right angle to themagnetic field. If the current is reversedwhen it has reached this position, the coilwill continue to revolve. The action of the motor can be simplyexplained by the diagram of Fig. 28 wherea motor armature, commutator and brushesas well as the field poles, are representedin a conventional manner. If the terminalsG, H, be connected to a source of directcurrent, part of the current will circulatethroug
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
