THE DESIGN OF ALTERNATING 
GENERATORS AND SYNCHRONOUS 
MOTORS. 
1. Duties of the Designer.—tThe duty of the designer is to 
provide in his design all the desirable elements of an 
alternator for the minimum manufacturing cost. The 
work of a designer seldom exceeds the calculation of mag- 
netic and electrical data of the machine. For the mechan- 
ical design he has the assistance of the drawing office 
staff; the workshop staff looks after the manufacturing, 
and, finally, the checking of the design is carried out in 
the test room. The satisfactory and economical work of 
all these departments is based on the requirements of the 
machine designer; therefore, he must: be conversant with 
mechanical construction, the general workshop methods 
of economical production and be able to read the test 
data and make his deductions therefrom. With further 
experience and knowledge obtained from past designs he 
-will be able to meet all the requirements of machinery 
users as well as the manufacturer. Roy 
2. Types of Alternators.—Alternating current practice has 
developed two classes of alternators, namely: (1) the 
separately excited alternator, which was until recently in 
exclusive use; and (2) the self excited alternator, which 
has been brought out recently. 
‘The separately excited generator receives its magnetizing 
current from a continuous current supply, which in most 
