Priority In Alternate Current Motors

Friday, September 11, 1891
Archived Page: 

THE ELECTRICAL ENGI _;i PRIORITY IN ALTERNATING-CURRENT MOTORS. The question of priority in the discovery ef the alternating-current motor would seem to need dednife settlement, both on account of historical accuracy and the avoidance of acrimonious discussion. It has been usual, in Europe, to ascribe to Prof. Ferraris the priority in the demonstration of the possibility of rotary motion being obtained from alternating currents, and in a recent résznne' of the subject M. Hospitalier so accorded the credit. The dispute, so far as fundamental principles are concerned,is limited to Prof. Ferraris and Mr. Nikola Tesla; and the New York Elect/'ical Engine/fr this week vigorously asserts the priority for America. in the person of Mr. Tesla. The following are the words of our contemporary: “ Prof. Ferraris has been credited with the discovery: new in controversy on the strength of his admirable paper, reall before an Italian scientific society, in March, 1888, and pub lished in Italian shortly afterwards. But five months before this, in October, 1887, Mr. Tesla had already filed appli cations for patents embodying the discovery, and several months before that time had so far perfected his invention that a company had been formed to exploit it. Many prominent persons, including several electricians, then saw the Tesla motors at work; and during the winter of 1887-5 one of the bcstfknown scientific men in this country (America) examined and reported favourably upon them. Seine time in April, one of the present editors of the New York Elect/'ical Engiiiecr, knowing of this new work, saw the motors which had then been running for some time in a temporary laboratory, and induced Mr. Tesla to bring his discovery before the May annual meeting of the American Institute of Electrical Engineers. The motors were actually shown in New York before a large gathering. “ On May 1, 1888-the same year-patents \vere issued to Mr. Tesla in America as the result of his application in October, and were then accessible at once in every European country. But the work of Prof. Ferraris was not brought to light in English-speaking countries (and others, too, for that matter) until it was given prominence by the publication of it in Industries, May 18, 1888. That interesting article was freely copied, as it well deserved, and its publication in this wise created the false idea that Prof. Ferraris’s striking work was simultaneous with thatof Mr. Tesla, or even prior. But the description of the Tesla invention must have evidently been made public ou the patent, in England and other countries, before the date of the I7lfl1I,Sf1`iES article, and besides the fact of the issue of the patents there is the fact that a contemporary, the New York Electrical Review, had given a short illustrated description of the Tesla motors on May 12. “More than this, in his essay of March, 1588, Prof. Ferraris expressly denied the practicability of motors that Mr. Tesla already had in successful operation l He hinted at the possibility of using a proper generator for such motors, but no further did he go. Mr. Tesla had already taken coal out of the mine before Prof. Ferraris had made his geological survey of the region. With this admission from Prof. Ferraris, it was not very likely that practical men would recognise the great value of the new principle. “ ')n examination of Mr. Tesla’s now familiar Work, we find that he, on the contrary, had not stopped short at a mere rotating field, but dealt broadly with the shifting of the resultant attraction of the magnets ; that he had evolved the multiphase system; that he had shown the broad idea of motors employing currents of differing phase in the armature with direct currents in the field; that he had shown both synchronising and torque motors; that he had shown how machines of ordinary construction might be adapted to his system, and had with specific pur- pose advanced boldly into new territory, of wnich there was not the slightest hint or suggestion in the work of Prof. Ferraris. In other words, Mr. Tesla not only went to the bottom of the fundamental principles, hut tried them in every detail that inventive ingenuity could hit upon. If this is not so, it is time to have the contrary state of affairs proved before Mr. Tesla loses the credit that such work must give him.” - ....