The Induction Motor. A Short Treatise on its Theory and Design, with numerous Experimental Data and Diagrams

Abstract

MR. BEHREND, in the preface to his book, rather offers an apology for adding one more to the already overwhelming number of books dealing with electricity and its applications. In some cases an apology of this kind is, unfortunately, justified; but in this instance, in view of the very great importance of the subject from the electrical engineer's point of view and the increasing introduction of polyphase electrical installations, a work on the above subject, written by a writer who, from his continental experience, should know what he is talking about, is to be welcomed. The author's point of view is made clear by a quotation from Prof. J. J. Thomson, printed on the title-page: “The absence of analytical difficulties allows attention to be more easily concentrated on the physical aspects of the question … than if he merely regarded electrical phenomena through a cloud of analytical symbols”; and on a first glance at the book, which consists of only 105 pages, one had hoped for a concise and easily comprehensible statement of the subject. This cannot, however, be said to be the case. The book could be very conveniently entitled “A notebook for the designer of induction motors,” and to an electrical engineer well versed in polyphase work it would be, without doubt, very useful. The reader who does not possess these qualifications will not find it of much value. The author admits this, in that he adds an appendix containing an extract from Gisbert Kapp's “Electric Transmission of Energy,” dealing with the elementary theory of the induction motor, and says that after reading this the reader will be better able to understand his own diagrams and deductions. We think, however, that the author would have done well had he made his reasoning a little more clear and detailed. The method adopted is the graphical method, a diagram being given for each machine, &c., considered. The diagrams are given with-out, in some cases, any of the reasoning which leads up to them. This to the engineer who thoroughly under-stands the subject does not matter, and to such we would recommend the book. Besides dealing with the general calculations concerned with single and polyphase motors, one chapter is devoted to the special design of a three-phase motor of 200 h.p.; and two chapters, the first and the last, deal with the theory of the alternating current transformer. In appendix ii. a graphical method is given for integrating some of the equations given in the body of the book. We think it is possible for this so-called “non-mathematical” treatment to be carried a little too far. The electrical engineer who does not wish to be severely handicapped in his profession must be able to work out an integration without having recourse to a roundabout method to avoid it, which is most likely only applicable to the particular case under consideration.

The Induction Motor. A Short Treatise on its Theory and Design, with numerous Experimental Data and Diagrams.

By B. A. Behrend. Pp. 105. (New York: The Electrical World and Engineer, 1901.