CHAPTER II 



THE LEADING DIMENSIONS OF A TRANSFORMER OF A GIVEN 



RATING 



A NUMBER of papers have been contributed to the proceed- 

 ings of scientific societies and to technical periodicals, dealing 

 with methods of determining upon the leading dimensions 

 when embarking upon a transformer design. Most of these 

 papers, however, are overweighted with complex formulae and 

 are useless to the practical designer. In the majority of 

 technical colleges the students investigate many interesting 

 phenomena concerning the transformer, but it is rare to find 

 a graduate who has the remotest idea of how to proceed in 

 designing a commercial transformer. This, of course, cannot 

 be due to any real difficulties associated with transformer 

 designing ; nothing is more simple and straightforward so far 

 as relates to the underlying principles. Nevertheless, like all 

 designing problems, there are very many practical points based 

 on long experience to which careful consideration must be 

 given. It is particularly true of transformer designing that 

 past experience goes a long way in aiding the engineer in the 

 case of any particular new design which he undertakes. It is 

 the object of the present chapter to set forth correct (though 

 simple) preliminary methods for guidance in the commercial 

 designing of transformers which are required to conform to 

 stipulated conditions. Various data, curves and rules will be 

 introduced from time to time to aid in carrying on the design 

 at those points where it is necessary to make assumptions. 

 The data thus introduced are based on my experience as 

 applied to a large number of designs of various ratings. So far 



