86 



Description of Modern Alternators. 



By the courtesy of the designers and 

 makers of alternators, the author is able 

 to submit particulars of the various 

 machines most in use, and he takes this 

 opportunity of tendering his thanks to 

 those who have supplied him with infor- 

 mation. Modern alternators may be 

 divided into two classes, disk machines 

 and drum machines. In the former type 

 the armature-coils are arranged in disk 

 form, and the magnet- poles are presented 

 to them from two sides, whilst in the 

 latter type the coils are arranged to form 

 a cylindrical surface, and the magnet- 

 poles are presented from one side only. 



DISK MACHINES. 



The Ferranti Alternator. 



The magnet-cores are of trapezoidal 

 section (Figs 13 and 14), and supported 

 in cast-iron yoke- rings. The armature- 

 conductor is a thin corrugated copper 

 strip, wound with a strip of vulcanized 

 fiber of equal width upon a brass core. 



