_ ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 195 
= 93.4 per cent., after having assumed 8,000 watts for 
friction and ventilation losses. 
375. Summary of Design.—The output constant character- 
izing the choice of the leading dimensions, will be found 
87.5° X 14.5 xX 300 
; — 3 
equal to 520 = 64 X 10°. 
The weights of the active and loss producing materials are: 
eS en ee oes en 1,150 pounds; 
UC) I ey ci! eS miles 
I IIMS oc kc ce et cee 5.960 °° 
This data, compared with that of Figs. 14 and 64, indicates 
that the present design is, on the average, a standard one. 
DESIGN OF A7J INDUCTOR TYPE SINGLE PHASE 
ALTERNATOR. 
376. General Specification of Alternator.—The single 
_ phase alternator in question is direct coupled to a turbine 
running at a speed of 1,050 R.P.M. 
The generator should be capable of delivering 55 KVA. 
_ to a lighting cireuit. 
A terminal pressure of 2,300 volts is required, with a fre- 
quency of 70 per second. 
377. Peripheral Speed.—From the following calculations 
it will be seen that for such a high speed as 1,050 R.P.M., 
an inductor type machine can be obtained with good 
electrical features and which at the same time will prove 
a commercial success. , 
In this particular type of alternator, having simply a revolv- 
ing part of iron, the peripheral speed can be driven much 
higher than in the ease of rotating magnet coils. 
Assuming a peripheral speed of 6,200 feet per minute, the 
