. Practical wireless telegraphy; a complete text book for students of radio communication . and the rate of the change of flux threading through S. For instance, if P has 100 turnsof comparatively coarse wire such as No. 14 or No; 16 B. & S. wound over an iron coreand S has many thousand turns of fine wire such as No. 36 B. & S., an electromotive forceof several hundred thousand volts may be induced in S. Should winding S have less turnsthan winding P, the E. M. F. induced in S will be lower than that of winding P. Ad-vantage of this principle is taken in the design of the apparatus known as t
. Practical wireless telegraphy; a complete text book for students of radio communication . and the rate of the change of flux threading through S. For instance, if P has 100 turnsof comparatively coarse wire such as No. 14 or No; 16 B. & S. wound over an iron coreand S has many thousand turns of fine wire such as No. 36 B. & S., an electromotive forceof several hundred thousand volts may be induced in S. Should winding S have less turnsthan winding P, the E. M. F. induced in S will be lower than that of winding P. Ad-vantage of this principle is taken in the design of the apparatus known as the inductioncoil, in which the circuit of P is interrupted from thirty to one hundred times per if winding S is given a large number of turns and its terminals are separated by aspace of several inches, the voltage may be so great as to jump the gap in the form of anelectric spark. To properly distinguish the various circuits, winding P is called the primary; winding Sthe secondary winding. The current in P is termed the primary current and in S thesecondary Fig. 20—Fundamental Diagram of Simple Alternator. 32. The Dynamo.—We may briefly define the dynamo as a machine forconverting mechanical energy into electrical energy by the principle of electro-magnetic induction. But unlike the simple battery or storage cell the dynamomay generate either direct or alternating current. Alternating current dynamosare frequently called alternators. The student can nearly always distinguishbetween the two machines by observing the part of the dynamo at which thecurrent is collected. If the brushes rest on a commutator made up of a numberof copper segments separated by insulating material, it will be a direct currentdynamo, but if the brushes simply rest on two brass rings, it will alternatingcurrent dynamo. The fundamental principle of the dynamo follows: Whenever a coil of wirerotates through a magnetic field of uniform strength in such a way that the ELECTROM
Size: 2017px × 1238px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
