INTRODUCTION 



The great importance of problem work in the training of stu- 

 dents of engineering is now generally recognized. No other work 

 so efficiently develops analytical power and dear, logical think- 

 ing, so necessary to success in the engineering profession. Yet 

 notwithstanding the importance of problem work in general, the 

 first consistently developed book of electrical engineering prob- 

 lems was that prepared by Mr. Lyon in 1908, its wide use being 

 conclusive evidence of the needs that were felt among both 

 teachers and students for such a work, and of the appreciation of 

 the importance of the training which it exemplifies. 



It requires a special gift to originate and develop problems 

 which shall give sound training in the fundamentals of engineering 

 and whose solution shall not only interest the student, but develop 

 his intellectual power as well. In general the problems must be 

 closely related to engineering practice, graded as to difficulty, 

 and must carefully avoid being mere mathematical puzzles. Mr. 

 Lyon, as his earlier book also shows, has a most unusual ability in 

 the preparation of problems for the electrical engineering field. 



The present collection of problems relating to electrical 

 machinery, more particularly in the field of alternating current 

 engineering, has been prepared with the same point of view as 

 was Mr. Lyon's earlier work, and should likewise prove most 

 ii-ehil to both instructor and student. 



H. K I II FORD. 



IIsuvARD UNIVERSITY, 

 December, li:i. 





