Category: rotating magnetic field




Nikola Tesla – The True Discoverer of the Rotating Magnetic Field

“Many erroneous statements have appeared in print relative to my discovery of the rotating magnetic field and invention of the induction motor which I was compelled to pass in silence. Great interests have waged a long and bitter contest for my patent rights; commercial animosities and professional jealousies were aroused, and I was made to suffer in more than one way. But despite of all pressure and efforts of ingenious lawyers and experts, the rulings of the courts were in support of my claims for priority in every instance without exception. The battles have been fought and forgotten, the thirty or forty patents granted to me on the alternating system have expired, I have been released of burdensome obligations and am free to speak…

”…A few words should be said in regard to the various claims for anticipation which were made upon the issuance of my patents in 1888, and in numerous suits conducted subsequently. There were three contestants for the honor, Ferraris, Schallenberger and Cabanellas. All three succumbed to grief. The opponents of my patents advanced the Ferraris claim very strongly, but any one who will peruse his little Italian pamphlet, which appeared in the spring of 1888, and compare it with the patent record filed by me seven months before, and with my paper before the American Institute of Electrical Engineers, will have no difficulty in reaching a conclusion. Irrespective of being behind me in time, Prof. Ferraris’s publication concerned only my split-phase motor, and in an application for a patent by him priority was awarded to me. He never suggested any of the essential practical features which constitute my system, and in regard to the split-phase motor he was very decided in his opinion that it was of no value. Both Ferraris and Schallenberger discovered the rotation accidentally while working with a Gullard and Gibbs transformer, and had difficulty in explaining the actions. Neither of them produced a rotating field motor like mine, nor were their theories the same as my own. As to Cabanellas, the only reason for his claim is an abandoned and defective technical document. Some over-zealous friends have interpreted a United States patent granted to Bradley as a contemporary record, but there is no foundation whatever for such a claim. The original application only described a generator with two circuits which were provided for the sole purpose of increasing the output. There was not much novelty in the idea, since a number of such machines existed at that time. To say that these machines were anticipations of my rotary transformer is wholly unjustified. They might have served as one of the elements in my system of transformation, but were nothing more than dynamos with two circuits constructed with other ends in view and in utter ignorance of the new and wonderful phenomena revealed through my discovery.“

–Nikola Tesla

“Some Personal Recollections.” Scientific American, June 5, 1915.




“They laughed at me in 1897 when I told them about the cosmic ray. Fifty years ago they attempted to discredit my discovery of the rotating magnetic field and my system of power transmission by alternating currents. They called me crazy when I predicted the radio and when I sent the first impulse around the world they said it couldn’t be done.”

–Nikola Tesla

In the Realm of Science: Tesla, Who Predicted Radio, Now Looks Forward to Sending Waves to the Moon.” New York Herald Tribune, August 22, 1937.

“Some Personal Recollections.” Short autobio by Nikola Tesla *audio* :

Listen to “Some Personal Recollections.” A short autobiography written by Nikola Tesla, in 1915, explaining his discovery of the rotating magnetic field, and the development of his alternating current induction motor.

“I would not give my rotating field discovery for a thousand inventions, however valuable, designed merely as mechanical contraptions to deceive the eye and the ear. A thousand years hence, the telephone and the motion picture camera may be obsolete, but the principle of the rotating magnetic field will remain a vital, living thing for all time to come.”

–Nikola Tesla

“A Famous Prophet of Science Looks Into the Future.” By Alden P. Armagnac. Popular Science Monthly, November, 1928.

Nikola Tesla was an inventor, discoverer, electrical engineer, mechanical engineer, theoretical and experimental physicist, mathematician, futurist and humanitarian. He is responsible for over ninety percent of the transmission of electrical power the world relies on today thanks to Tesla’s discovery of the rotating magnetic field. The inventor utilized this discovery in his invention and patent of the first commutatorless alternating current induction motor which changed the future of power transmission. All electrical technology using or generating alternating current today is due to Tesla, without which all our trolley cars, electric vehicles, subways, manufacturing/industrial plants and electrified power lines, which bring power to almost every single electrical appliance/equipment in you house/work, would be impossible.

Tesla was a Serbian born on today’s date at midnight in Smiljan, Lika (what is now Croatia). He was educated at an early age by his parents then attended the Gymnasium Karlovac in Croatia, the Polytechnic Institute in Graz, Austria; and the University of Prague excelling in linguistics, mathematics and sciences. He was a hyper-polyglot who could speak eight languages including: Serbo-Croatian, English, Czech, French, German, Hungarian, Italian, and Latin, and he claimed to have had a three-dimensional memory and thought process that tormented him in his youth, but later aided him with building his inventions in his own mind without wasting any physical energy. He was known to be able to recite by heart full books, mathematical formulas and poetry such as Goethe’s “Faust,” Njegoš’ “The Mountain Wreath,” Dante’s “Divine Comedy,” Shakespeare’s “Hamlet,” Byron’s “Childe Harold’s Pilgrimage,” and Pushkin’s “Eugene Onegin.”

In 1881 while walking with a friend in a City Park reciting Goethe’s “Faust,” Tesla first envisioned the rotating magnetic and his induction motor, complete, perfect, operable in form. This visualization would represent the same diagrams he would show in his 1891 lecture before the American Institute of Electrical Engineers.

After his revelation, in 1882 Tesla’s began working for a telephone company in Europe for a few years, independently working on his induction motor, until he moved to America in 1884 in hopes of capitalizing on his new discovery. Initially, Tesla was hired by Thomas Edison, but the great American inventor was not interested in Tesla’s alternating current system due to his already strong interest in direct current power system. Tesla would continue working for Edison until Edison promised him $50,000 to make improvements on his DC generation plants. After completing the task, Tesla asked to be paid, but Edison denied him his offer and explained that the offer of $50,000 was just an “American joke.” Edison offered Tesla a small raise, but Tesla would resigned instead.

After digging ditches for a short time, Tesla was offered his own lighting company by some small investors, but were also not interested in his induction motor. It wasn’t until George Westinghouse took notice of Tesla’s invention and threw all his resources into Tesla’s work. This new industry in power transmission would start a feud between the Westinghouse Company and General Electric, known as the “War of Currents” (AC/DC)…

(to be continued…)

“When I made the discovery of the rotating magnetic field I was a very young man. The revelation came after years of concentrated thought and it was my first great thrill.

“It was not only a valuable discovery, capable of extensive practical applications. It was a revelation of new forces and new phenomena unknown to science before.

“No, I would not give my rotating field discovery for a thousand inventions, however valuable, designed merely as mechanical contraptions to deceive the eye and the ear. A thousand years hence, the telephone and the motion picture camera may be obsolete, but the principle of the rotating magnetic field will remain a vital, living thing for all time to come.”

–Nikola Tesla

“A Famous Prophet of Science Looks Into the Future.” By Alden P. Armagnac. Popular Science Monthly, November, 1928.

“One afternoon I was walking with a friend in the City Park and reciting poetry. At that time I knew entire books by heart, word for word. One of these was Goethe’s “Faust;” and the setting sun reminded me of the passage:

“The glow retreats, done is the day of toil;
It yonder hastes, new fields of life exploring;
Ah, that no wing can lift me from the soil,
Upon its track to follow, follow soaring!

“Even while I was speaking these glorious words, the vision of my induction motor, complete, perfect, operable, came into my mind like a flash. I drew with a stick on the sand the vision I had seen. They were the same diagrams I was to show six years later before the American Institute of Electrical Engineers. My friend understood the drawings perfectly; and to me the images were so real that suddenly I cried, “Look! Watch me reverse my motor!” And I did it, demonstrating with my stick.

This discovery is known as the “rotating magnetic field.” It is the principle on which my induction motor operates.”

–Nikola Tesla

“Making Your Imagination Work For You.” American Magazine, April, 1921.