12 



ELEMENTS OF ELECTRICAL ENGINEERING. 



magnetizing action. This reversing device is called a rectifier ; 

 and an alternator provided with a rectifier and a series field wind- 

 ing is called a composite or compound alternator. 



The essential features of the connections of a compound alter- 



To receiving circuit 



Fig. 14. 



nator are shown in Fig. 14. The series field winding CC is 

 connected into the main alternating-current circuit through the 

 rectifier, 5, which is essentially a reversing switch, and the cur- 



JYimary coil 



Fig. 15. 



rent in CC flows always in one direction although the current 

 in the main circuit is an alternating current. 



Instead of tapping the coil CC into the main circuit, it is 

 usually connected to the secondary coil of a small transformer 



