128 ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 
according to Equation (388) the peripheral velocity is 
171.4 x 500 
Ce 
Although the velocity is above the average value, there is 
no difficulty in designing the rotating part to have the 
necessary mechanical strength. 
212. Pole System.—tThe poles are fixed to the wheel rim in 
dovetailed tunnels and the projecting part of the pole is 
of ample strength, having a thickness of 1.2 inches. 
= 7,150 feet per minute. 
R 
N —T 
booc 
3500 Lf 
7 
8 ‘al 
400 ms 
CTE: 
2000 | 82 on 
nf aS 
4000 [ 20\70C' 
Rf <— FR ; aa 
F A _— -_ 5) 50 
2000 4000 6000 8000 10000 ATEAO) 
700 200 300 400 $00 HVA. 
Fie. 67.—TEsST DATa OF A 400 KVA., 3,500 VoutTs, 500 Revys., 
50-CycLE 3-PHASE ALTERNATOR. 
The edge wound, flat copper strip magnet coils make a very 
reliable coil system. 
The wheel rim section is large enough to be mechanically 
strong. 
213. Pole Pitch.—The poles are 12 in number and according 
500 x p 
to Equation (7) the frequency = 60 = 50, where 
