ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS.,. 189. 
45.7 
14.25 X 0.95. 
The materiai of the wheel rim is cast iron, which must be of 
ample section, of sufficient mechanical strength and so 
designed as to produce the necessary flywheel effect. There- 
fore, to comply with the above requirements, the section 
of the rim should be 20 by 4.75 inches. 
In this particular case there is a suitable die for the pole 
stampings, so, for the sake of convenience, we adopt the 
= 3.5 inches. 
will be equal to 
Fie. 84.—PoLE WINDING oF 520 KVA., 2,800 Voit, SINGLE 
PuasE ALTERNATOR. 
dimensions of 3.5 by 8.25 inches. From previous designs 
of the present type of machine it is known that the avail- 
able winding space is ample, see Fig. 84. 
363. Ampere Turns and Air Gap.—Corresponding to the 
specified regulation and considering the degree of iron 
saturation, we allow a ratio of 2.5 to 1 between the ampere 
turns of the field and of the armature. 
The value of the armature back ampere turns is 0.9 X 
576 XX 186 
— = 48,500. Therefore, the amount of the total 
