Magneto- and Dynamo-Electric Machines

Abstract

THIS work, which is considerably enlarged from its first appearance, now includes accounts of all the leading forms of dynamo- and magneto-electric machines with the exception of those of Edison, of which no mention is made. The first chapter is devoted to generalities concerning electromagnets, induction, &c. The second describes magneto-electric machines beginning with that of Pixii and ending with that of De Meritens. The third chapter, on dynamo-electric machines, opens with a rather unseemly revival of the dispute as to priority between Werner Siemens and Wheatstone in the discovery of the action-and-reaction principle of the so-called dynamo-machines. It is a matter of history that papers announcing this discovery were read before the Royal Society on the very same day (February 14, 1867) by Wheatstone and by Dr. C. W. Siemens. We cannot help thinking that Dr. Schellen, in his manner of describing the affair, allows himself to take an attitude extremely unjust towards the great English physicist, now no longer amongst the living; and we protest against this very needless attempt to arouse a scandal. Nor is it true that Wheatstone's memoir contained nothing that Werner Siemens had not previously published in Berlin. The proof of this matter is that Wheatstone's principle of exciting the field-magnets by a derived current in a shunt circuit was adopted as a “new method” by Messrs. Siemens Brothers within two years from the present date, and formed, in 1881, the basis of a communication by Dr. C. W. Siemens to the Royal Society, and of another by Mr. Alexander Siemens to the Society of Telegraph Engineers, in which the priority of Wheatstone in this detail is fully and explicitly admitted. In this chapter also the machines invented by Weston and by Brush are described. Chapter IV. treats of those dynamo-electric machines which generate continuous currents, beginning with Pacinotti's machine of 1863, and including the well-known forms of Gramme and Siemens (v. Hefner-Alteneck), the latter of which is described in very great detail. Hefner-Alteneck's new large dynamo with a disk-armature and many peripheral coils, is mentioned, and the general arrangement of its parts shown. The fifth chapter treats of alternate-current machines. Those of Lontin, Gramme, and Siemens are described fully, but the name of Wilde is not even mentioned ! A new machine by Siemens and Halske, capable of giving either intermittent-direct or alternate currents, is figured in this chapter. This section of the book is closed by a disquisition on the theory of dynamos and their efficiency, the greater part being a compilation from the researches of Frolich, Hagenbach, and others.

Die Magnet und dynamo-elektrischen Maschinen.

Von Dr. H. Schellen. Zweite, nach dem gegenwärtigen auf der Pariser electrischen Ausstellung vertretenen Zustande dargestellte und vermehrte Auflage. (Köln, 1882.)