SYNCHRONOUS MACHINERY 239 



The power supplied by the alternator is as before 

 P = 3 El cos 

 = V3 E t li cos 0. 



143. Alternator Windings. There are a great many special 

 alternator windings but the majority of them come under the two 

 classes of chain windings and double-layer windings. 



Four Pole, Single Phase, Chain Winding 



Tour Pole, Two Phase, Chain Winding 



Si S 2 S3 JL/i /2 



Four Pole, Three Phase, Chain Winding 



FIG. 207. Concentrated chain windings. 



If. 



Fig. 207 shows four-pole single-, two- and three-phase chain 

 windings for armatures with one slot per phase per pole. These 

 windings are all concentrated windings. 



Fig. 208 shows the corresponding double-layer windings. 



Fig. 209 shows a four-pole single-phase chain winding distributed 



