ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 151 
The edges of the pole pieces are cut in order that, ag far 
as possible, a sinusoidal wave form may be obtained, see 
Fig. 71. 
275. Output Coefficient.—The output coefficient of this low 
169? * 5.5 K 93.75 
—_ x 10? 
395 40.4 X 10%, 
which agrees with that of a standard machine, see Fig. 
64; but in spite of this fact the amount of material in 
speed polyphase alternator is 
rth 
HMUUMMIMIIMIMMMUHIU A, 
26" 
TL 
+ 
a 
Sas 
\7 
© 
Fie. 71.—PoLe WInpING, 375 KVA., 
3,000 VouTs 2-PHASE ALTER- 
NATOR. 
Fie. 72.—Stor WInp- 
ING OF THE 375 KVA., 
3,000 VoLTs 2-PHASE 
ALTERNATOR. 
the low speed machine will be found much in excess of 
that in a standard machine. 
The difference is especially noticeable in the amount of idle 
material, such as the extra weight of material in the cast 
iron frame. 
2%6. Normal Total Flux.—With regard to the basis of the 
most economical division of the active iron and copper 
material, we find that the normal flux is about 27 per 
