206 ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 
The efficiency of the machine under discus- 
55.000 
62,420' ised oe 
The friction and ventilation losses in this case are assumed 
to be 1,600 watts. 
401. Efficiency. 
sion will be 
402. Summary of Design.—The resulting good commercial 
features of the alternator have been obtained with an 
2 
23¢ X 2 X 6X 1050 _ 155 age 
dd 
which, for a high tension and single phase alternator, is a 
standard value. 
The active and loss contributing materials are composed 
of 1,200 pounds of armature stampings, 95 pounds arma- 
ture copper, and 330 pounds of field copper, which point 
to a successful commercial design. 
It must be kept in mind that, for low or medium speeds, 
it is difficult to obtain a good design of inductor type 
alternator which embodies very good electrical features. 
complying at the same time with the conditions of 
economy. 
output coefficient of 
403. Design Sheet.— Table 23 illustrates a typical design 
sheet, on which all the necessary data required for a given 
design is collected in a very handy form. 
The Table in question gives the data for the caleulations of 
a 175 KVA. alternator. 
404, Formule Used in Design.—At this stage it will be 
well to tabulate the various formule which are used in 
the examples of alternator design given above. 
' Such a list forms a very handy reference, the more so, as it 
is not absolutely necessary for such formule tu be com- 
mitted to memory. 
A list of the symbols and specific quantities used in the 
following formule is given at the beginning of this book. 
CAPACITY OF THE ALTERNATOR: KVA.= E X C. in the ease 
of single phase open winding; KVA. = 2E  X C. in the case 
