ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 13 
Fie. 6A.—InpuctTor Typx, 50 CrcLge, PoLYPHASE ALTERNATOR’ 
oF EuRoPpEAN Desien. (See Table 3a.) 
‘TABLE 3a._DIMENSIONS OF INDUCTOR TYPE, 50 CYCLES, 
POLYPHASE ALTERNATORS. (SEE FIG. 6a.) 
. | 
RVAd Bey eh 4 B G Poi eee Kode |. BE. Pe 
45 | 1,000 | 4,850; 657| 43” | 21” | 34” | 10% | 1137] 15377] 184”| 407 
65 | 1,000 | 6,400| 78 | 453 | 22 | 45 | 11 | 123 | 15h [20% | 40 
100 | 750] 9,300| 89 | 52 | 2G: | 49 | 134] 14 | 19$ |225 | 53 
130 | 600/14,100] 98 | 60 | 23¢ | 53 | 168 | 194 | 23$ | 26 | 55 
200 | 600 | 17,600 /104 | 604 | 30% | 56 | 174 | 214 | 234 | 265 -|-614 
275 | 600 | 21,800'115 | 67 | 314 | 61 | 228 | — | — |{33$ | 61 
325 | 500 | 31,100 |1174 | 8i} | 31¢ | 63% | 298 | — | — |3sk | 62h 
550 | 375 |52,800)150 | 93 | 33 | 86s | 305 | — | — [41s | — 
| 800 | 300 | 84,700 /156 | 98 | 36) | 86} | 33h | — | — |44 | — 
28. Choice of Materials.—The first consideration of the 
designer has to be directed toward the choice of the dif- 
ferent materials, and, secondly, to the constructional 
details with regard to manufacturing expenses, repairs, 
interchangeability facilities, erection and transportation 
conditions. 
In the following paragraphs the different parts of a revolv- 
ing field type alternator will be discussed. 
THE ARMATURE. 
29. The Armature.—tThe armature of a high speed or medium 
speed generator of average size has comparatively mod- 
