viii PREFACE 



It has been deemed desirable tbat tbe present work should 

 deal \vitli the fundamental principles of practical designing, 

 but so soon as these principles have been assimilated, the 

 reader should proceed to stud}' carefully the many essential 

 constructional details. A Bibliography of a considerable 

 number of papers relating to static transformers is given at 

 the end of Chapter I. In conclusion, I wish to acknowledge 

 the work of my former assistant, Mr. Evelyn Good, who 

 carried through many of the calculations, under my direction, 

 and prepared a good many of the curves and diagrams. .My 

 assistant, Mr. C. Martin, compiled from my data certain 

 portions of Chapters VIII. and IX. My thanks are due to 

 the several manufacturing companies whose designs are 

 described for their courtesy in providing me with the necessary 

 information and for photographs and drawings. 



H. M. HOBART, M. INST. C.E. 

 LONDON, 



December, 1910. 



