PROPERTY OF ELECTRICAL LABORATORY, 



FACULTY OF APPLIED SCIENCE. 



Date. 



PREFACE. 



THIS volume deals in an elementary and practical manner 

 with the principles of alternating currents and alternating- 

 current machinery. It is hoped that it may prove of 

 special use to students in technical schools and colleges 

 in connection with their laboratory work, and to young 

 engineers engaged in handling or testing alternating- 

 current machinery. 



The writer hopes that the book may also appeal to a 

 wider range of readers who wish to gain some practical 

 insight into alternating-current working. He believes 

 that the experimental method of treatment is for this 

 purpose the one best fitted to convey exact and concrete 

 ideas, even to the student who is unable himself to carry 

 out the measurements described. He has thus aimed 

 at producing a text-book on the principles of alternating- 

 current working, as well as a companion to the laboratory 

 or test house. The experiments are described in great 

 detail, so as to enable the conclusions derived from them 

 to be followed by the reader who has not the means for 

 obtaining experimental results of his own. 



It will be seen that the use of the higher mathematics 

 has been avoided, except in the final chapter on curve 

 analysis, and, as far as possible, a treatment based on 

 actual results and examples has been employed. 



With regard to the selection of the experiments, some 

 of the earlier ones have been given mainly for the sake 

 of the principles involved, or as exercises in calculation. 

 In the later part of the book, while the most general 



