PREFACE 



Those problems chiefly concern the theory of the operation of 

 alternating current machinery, and are such as we give to the 

 fourth year students in electrical engineering in this subject. 



In each chapter the problems of a similar nature are grouped 

 together, and those of each group are then arranged in the 

 approximate order of their difficulty. The groups in each chapter 

 follow each other in as logical an order as possible, both from point 

 of difficulty and the presentation of the subject. 



In order that this collection of problems may be useful among 

 different classes of students a large variety has been included, 

 ranging from the very simple to those of considerable difficulty. 

 Wherever it is essential the data have been taken from actual 

 apparatus. This was possible through the courtesy of two of 

 the large manufacturing companies. In some of the problems 

 so few data are given that approximate methods of solution 

 must be used, but care has been taken to so state them that 

 the errors thus introduced need not be large. This lack of data 

 quently met in practice. 



It has been thought best not to give introductory paragraphs 

 for each chapter as was done in the preceding volume of prob- 

 lems inasmuch as they would have to be of considerable length 

 to be of much value. 



The answers to the problems will probably be ready for 

 publication in the fall of 1914. They will be available to all 

 but undergraduate students at a nominal price. Undergraduate 

 student< can obtain them only on the recommendation of their 

 Instructors. 



WALDO V. LYON. 



MASSACHUSETTS INSTITUTE OF TECHNOLOGY, 

 December, !'.: 



