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THE DESIGN OF ALTERNATING 
GENERATORS AND SYNCHRONOUS 
MOTORS. _ 
DESIGN A REVOLVING FIELD TYPE THREE-PHASE ALTERNATOR TO THE 
FOLLOWING SPECIFICATION: 
Output = 250 KVA. 
Speed = 375 Revs. 
Frequency = 50 Cycles. — 
Terminal pressure = 3,300 Volts, 
Connection of armature = Star. 
Load power factor cos Pp = .80. 
The efficiency shall not be below 92% at full inductive load. 
The voltage drop shall not exceed 16% at full inductive load. 
‘The temperature rise on any part of the machine shall not exceed 
75 degrees Fahrenheit. 
For the armature winding the long coil type in open slots is te 
be applied and the armature core is to be made up of .02 inch - 
lamine. 
For the poles .04 inch 1 lamine are to be 28 sae 
20%. Determine the necessary number of poles. 
2€8. Calculate the output of the prime mover to which this alter- 
nator has to be coupled. 
209. By means of Fig. 62 of the Instruction Book, determine the 
most suitable flux to be applied for this alternator. 
210. The number of slots per pole and phase being chosen to 2 
7 a 
and the pole are ratio to r= .65, state by means of Table 
