THE ALTER] 



W IABORATORY, 



FACULTY OF APPLIEO SCIENCE. 



BATING CURRENT GENERATOR 25' 



. 



consists of two coils, H and H' t both of which are excited 

 from the terminals of the exciter. One of them, H, is excited 

 all the time the exciter is running while the other H' is 

 excited only when the two contact points C and C" make 

 connection with each other. These two coils are differen- 

 tially wound, so that, when both of them are excited, there 

 is no pull on the armature S and the relay contacts E and 



Pivot 



Pivot L? 



Bg C' 



Compounding 

 /"Winding 



Pivot 



so 



Solenoid 



'Alternator 



Exciter 



FIG. 157. Connection Diagram of Voltage Regulator. 



E' remain closed by the action of the spring K, but when 

 contacts C and C' are opened so that only coil H is excited 

 the solenoid F is magnetized, the armature S is pulled down, 

 and the contacts E and E' are separated. 



The contacts E, E' are connected to the field rheostat of 

 the exciter, so that when they are together the rheostat is short- 

 circuited but when they are apart the rheostat is in the field 

 circuit as it is ordinarily. Hence, when C and C' touch 



