by Marc Seifer
By studying acoustical-wave motion in association with mechanical, electrical, and optical phenomena, Mach discovered that when the speed of sound was achieved, the nature of an air flow over an object changed dramatically. This threshold value became known as Mach 1.
Mach also wrote on the structure of the ether and hypothesized that it was inherently linked to a gravitational attraction between all masses in the universe. Influenced overtly by Buddhist writings, which no doubt filtered down to esoteric discussions by the university students, Mach could hypothesize that no event in the universe was separate from any other. “The inertia of a system is reduced to a functional relationship between the system and the rest of the universe.”27 This viewpoint was extended to the relationship of mental events to exterior influences. Like Stumpf, he agreed that every mental event had to have a corresponding physical action.28
Since Mach’s writings so closely parallel Tesla’s later research and philosophical outlook, Mach seems a curious omission from Tesla’s published writings.
By the time Tesla left the university at the end of the term, he had made great strides, both theoretical and practical, in solving the AC dilemma. “It was in that city,” Tesla said, “that I made a decided advance, which consisted in detaching the commutator from the machine and studying the phenomena in this new aspect.”29
With the death of his father, he needed to earn his own living. He began an apprenticeship in teaching but did not enjoy it. Uncle Pajo suggested that he move to Hungary, where employment could be obtained through a military friend, Ferenc Puskas, who ran the new “American” telephone exchange with his brother Tivadar.30 In January 1881, Tesla moved to Budapest, but he found to his dismay that the operation had not yet been launched.
The Puskas brothers were very busy men, running operations in St. Petersburg and overseeing, in Paris, Thomas Edison’s incandescent lamp exhibit at the Paris Exposition and fixing the lighting system at the opera house there.31 Out of funds and without a job, Tesla approached the Engineering Department at the Central Telegraph Office of the Hungarian government and talked his way into a position as a draftsman and designer. Working for a subsistence salary, he utilized what little surplus funds he had to purchase equipment to further his experiments.
Anthony Szigeti, a former classmate and engineer from Hungary, “with the body of Apollo…[and] a big head with a lump on the side…[that] gave him a startling appearance,”32 became Tesla’s friend and confidant. Many a night, when the budding inventor was not enmeshed in his research, the two fellows would meet at the local cafes, where they would discuss the events of the day or compete in such friendly games as determining who could drink the most milk. On one such occasion, Tesla claimed he was beaten after the thirty-eighth bottle!33
Due to his meager funds and general inability to budget himself, Tesla had but one suit, which had withered from use. It was the time of a religious festival, and Szigeti inquired what Tesla would be wearing. Stuck for an answer, the youthful inventor came upon the clever idea of turning his suit inside out, planning thereby to show up with a seemingly new set of clothes. All night was spent tailoring and ironing. But when one starts with a wrong premise, no amount of patching can right the problem. The outfit looked ridiculous, and Tesla stayed home instead.34
In a few months, the American telephone exchange opened there in Budapest and Tesla and Szigeti immediately gained employment. The new enterprise allowed the young engineers to finally learn firsthand how the most modern inventions of the day operated. It was also the first time that Tesla was introduced to the work of Thomas Edison, the “Napoleon of Invention,” whose improvements on Bell’s telephone helped revolutionize the field of communications. Up the poles Tesla would climb to check the lines and repair equipment. On the ground he worked as a mechanic and mathematician. There he studied the principle of induction, whereby a mass with an electric or electromagnetic charge can provide a corresponding charge or force or magnetism in a second mass without contact. He also studied a number of Edison’s inventions, such as his multiplex telegraph, which allowed four Morse-coded messages to be sent in two directions simultaneously, and his new induction-triggered carbon disk speaker, the flat, circular, easily removable device which is still found in the mouthpiece of every telephone today. As was his nature, Tesla took apart the various instruments and conceived ways of improving them. By giving the carbon disk a conical shape, he fashioned an amplifier, which repeated and boosted transmission signals. Tesla had invented a precursor of the loudspeaker. He never bothered to obtain a patent on it.
Except for friendly diversion with Szigeti, Tesla’s every spare moment was spent reworking the problem of eliminating the commutator in DC machines and harnessing AC without cumbersome intermediaries. Although a solution seemed imminent, the answer would not be revealed. Hundreds of hours were spent building and rebuilding equipment and discussing his ideas with his friend.35
He pored over his calculations and reviewed the work of others. Tesla later wrote: “With me it was a sacred vow, a question of life or death. I knew that I would perish if I failed.”36 Monomaniacal in pursuit of his goal, he gave up sleep, or rest of any kind, straining every fiber to prove once and for all that he was right and Professor Poeschl and the rest of the world were wrong. His body and brain finally gave out, and he suffered a severe nervous collapse, experiencing an illness that “surpasses all belief.” Claiming that his pulse raced to 250 beats per minute, his body twitched and quivered incessantly.37 “I could hear the ticking of a watch…three rooms [away]. A fly alighting on a table…would cause a dull thud in my ear. A carriage passing at a distance…fairly shook my whole body…I had to support my bed on rubber cushions to get any rest at all…The sun’s rays, when periodically intercepted, would cause blows of such force on my brain that they would stun me…In the dark I had the sense of a bat and could detect the presence of an object…by a peculiar creepy sensation on the forehead.” A respected doctor “pronounced [his] malady unique and incurable.” Desperately clinging to life, Tesla was not expected to recover.38
Tesla attributes his revival to “a powerful desire to live and to continue the work” and to the assistance of the athletic Szigeti, who forced him outdoors and got him to undertake healthful exercises. Mystics attributed the event to the triggering of his pineal gland and corresponding access to higher mystical states of consciousness.39 During a walk in the park with Szigeti at sunset, the solution to the problem suddenly became manifest as he was reciting a “glorious passage” from Goethe’s Faust.
See how the setting sun, with ruddy glow,
The green-embosomed hamlet fires.
He sinks and fades, the day is lived and gone.
He hastens forth new scenes of life to waken.
O for a wing to lift and bear me on,
And on to where his last rays beckon.
“As I uttered these inspiring words,” Tesla declared, “the truth was [suddenly] revealed. I drew with a stick on the sand the diagrams shown six years later in my address before the American Institute of Electrical Engineers…Pygmalion seeing his statue come to life could not have been more deeply moved. A thousand secrets of nature which I might have stumbled upon accidentally I would have given for that one which I had wrestled from her against all odds and at the peril of my existence.”40
Tesla emphasized that his conceptualization involved new principles rather than refinements of preexisting work.
The AC creation came to be known as the rotating magnetic field. Simply stated, Tesla utilized two circuits instead of the customary single circuit to transmit electrical energy and thus generated dual currents ninety degrees out of phase with each other. The net effect was that a receiving magnet (or motor armature), by means of induction, would rotate in space and thereby continually attract a steady stream of electrons whether or not the charge was positive or negative. He also worked out the mechanism to explain the effect.41
Follow the letter N in each of the
stages above.
Motor Schematics Showing Magnetic Field Rotation.
Tesla referred to this diagram (or one quite similar to it) in his lecture before the American Society of Electrical Engineers for the first time in 1888. Each square represents the same armature at different points in its rotation. There are two independent circuits or currents set up diagonally across from one another which are 90 degrees out of phase with each other in both position and timing. So, for instance, in the first position, the armature points to the north pole (of the north/south circuit, which runs from bottom right to top left). The other circuit (running from bottom left to top right) is in the position of changing so that neither pole has a charge. If we look to the next square to the right (which is occurring a fraction of a second later as the currents continue to alternate), we note that the charge is beginning to enter the second circuit (i.e., running from bottom left to top right). At this point in the other circuit, the charge is beginning to reverse itself as well but still has the same polarity. As there are two north poles set up at this fraction of a second, the armature rotates to go between the two of them. In the third square, the bottom right-top left circuit is now neutralized on its way to reversing its polarity, while the bottom left-top right circuit maintains the polarity it has just entered. Therefore, the armature continues its movement to the most northward position, and so on.42
“In less than two months,” Tesla wrote, “I evolved virtually all the types of motors and modifications of the system now identified with my name…It was a mental state of happiness as complete as I have ever known in life. Ideas came in an uninterrupted stream and the only difficulty I had was to hold them fast.”43 Tesla invented, at this time, not only single-phase motors whereby the two circuits were 90 degrees out of phase with each other, but also polyphase motors which used three or more circuits of the same frequency in various other degrees out of phase with each other. Motors would be run entirely in his mind; improvements and additions to design were conceived; finally, plans and mathematical calculations would eventually be transferred to a notebook. This step-by-step procedure would become customary.
Ferenc Puskas, who had initially hired Tesla, asked if he wanted to help his brother Tivadar run the new Edison lighting company in Paris. Tesla said, “I gladly accepted.”44 Szigeti was also offered a position, so Tesla was fortunate to have a good friend with whom he could share the new adventure.
Was Tesla the first to conceive of a rotating magnetic field? The answer is no. As far back as 1824, a French astronomer by the name of François Arago experimented with spinning the arm of a magnet by using a copper disc.
The first workable rotating magnetic field similar to Tesla’s 1882 revelation was conceived three years before him by Mr. Walter Baily, who demonstrated the principle before the Physical Society of London on June 28, 1879, in a paper entitled “A Mode of Producing Arago’s Rotations.”45 The invention comprised two batteries connected to two pairs of electromagnets bolted catty-corner to each other in an X pattern, with a commutator used as a switching device. The rotating magnetic field was initiated and maintained by manually cranking the commutator. On this occasion Baily stated, “The disk can be made to rotate by means of intermittent rotation of the field effected by means of electromagnets.”46
Two years later, at the Paris Exposition of 1881, came the work of Marcel Deprez, who calculated “that a rotating magnetic field could be produced without the aid of a commutator by energizing electromagnets with two out-of-step AC currents.”47 However, Deprez’s invention, which won an award at the electrical show, had a major problem: One of the currents was “furnished by the machine itself.” Furthermore, the invention was never practically demonstrated.48
Other researchers who conceived of a rotating magnetic field analogous to Tesla’s but after his revelation (in early 1882) were Professor Galileo Ferraris of Turin, Italy (1885-88), and an American engineer, Charles Bradley (1887). Ferraris was influenced by the work of Lucien Gaulard and George Gibbs, who designed AC transformers during the mid 1880s. In 1883 they presented their AC system at the Royal Aquarium in London,49 and in 1885 they installed an AC system of power distribution in Italy, where they met Ferraris.50 Purchased by George Westinghouse for $50,000, the system was installed in Great Barrington, Massachusetts, the following year by William Stanley, Westinghouse’s head engineer. The Gaulard-Gibbs invention, however, did not do away with the commutator, which was the express purpose of Tesla’s design.
In Ferraris’s published treatise on his independent discovery of a rotating magnetic field, he wrote, “This principle cannot be of any commercial importance as a motor.” After learning of Tesla’s work, Ferraris stated, “Tesla developed it much further than [I]…did.”51
Bradley filed for a patent for an AC polyphase device on May 8, 1887 (no. 390,439) after nine Tesla AC patents had been granted. Haselwander, in the same year, utilized slip rings in place of commutators on DC Thomson-Houston equipment and also designed two- and three-phase windings on DC armatures.52
The question of priority concerning Tesla’s invention was discussed by Silvanus P. Thompson, a physics professor in London, in his 1897 comprehensive text on AC motors. Thompson (no relationship to Elihu Thomson), considered at the time to be “perhaps the best known writer on electrical subjects now living,” said that Tesla’s work separated itself clearly from predecessors and contemporaries in his “discovery of a new method of electrical transmission of power [emphasis added].”53
A question that remains unanswered was whether or not Tesla knew of Baily’s work. It is quite possible that he had read Baily’s paper, although no one at the time, including Baily, comprehended the importance of the research or understood how to turn it into a practical invention.54 Tesla stated in the early 1890s, “I am aware that it is not new to produce the rotations of a motor by intermittently changing the poles of one of its elements…In such cases, however, I imply true alternating currents; and my invention consists in the discovery of the mode or method of utilizing such currents.”55
A few years later, in a well-publicized case involving patent priorities on what came to be known as the “Tesla Alternating Current Polyphase System,” Judge Townsend of the U.S. Circuit Court of Connecticut noted that before Tesla’s invention and lecture to the American Institute of Electrical Engineers (AIEE) in 1888, there had been no AC motors; furthermore, no one attending the lecture recognized any priorities. Whereas Baily had dealt with “impractical abstractions, Tesla had created a workable product which initiated a revolution in the art.”56 The Tesla patents were also sustained against individual cases involving Charles Bradley, Mons. Cabanellas and Dumesnil, William Stanley, and Elihu Thomson.57
In citing a previous case on a similar issue, Judge Townsend responded to what today is called the “doctrine of obviousness”:
The apparent simplicity of a new device often leads an inexperienced person to think that it would have occurred to anyone familiar with the subject, but the decisive answer is that with dozens and perhaps hundreds of others laboring in the same field, it had never occurred to anyone before [Potta v. Creager, 155 U.S. 597]…Baily and the others [e.g., Bradley, Ferraris, Stanley] did not discover the Tesla invention; they were discussing electric light machines with commutators…Eminent electricians united in the view that by reason of reversals of direction and rapidity of alternations, an alternating current motor was impracticable, and the future belonged to the commutated continuous current…
It remained for the genius of Tesla to…transform the toy of Arago into an engine of power.58
The discovery of how to effectively harness the rotating magnetic field was really only a fraction of Tesla’s creation. Before his invention, electricity could be pumped approximately one mile, and then only for illuminating dwellings. After Tesla, electrical power could be transmitted hundreds of miles, and then not only for lighting but for running household appliances and industrial machines in factories. Tesla’s creation w
as a leap ahead in a rapidly advancing technological revolution.
4
TESLA MEETS THE WIZARD OF MENLO PARK (1882-85)
O, he’s a great talker, and, say, he’s a great eater too. I remember the first time I saw him. We were doing some experimenting in a little place outside Paris, and one day a long, lanky lad came in and said he wanted a job. We put him to work thinking he would soon tire of his new occupation for we were putting in 20-24 hours a day, then, but he stuck right to it and after things eased up one of my men said to him: “Well, Tesla, you’ve worked pretty hard, now I’m going to take you into Paris and give you a splendid supper.” So he took him to the most expensive cafe in Paris—a place where they broil an extra thick steak between two thin steaks. Tesla stowed away one of those big fellows without any trouble and my man said to him: “Anything else, my boy? I’m standing treat.” “Well, if you don’t mind, sir,” said my apprentice, “I’ll try another steak.” After he left me he went into other lines and has accomplished quite a little.
THOMAS EDISON1
Taking the advice of Ferenc Puskas, Tesla left Budapest for Paris in April 1882 delighted with the chance to meet the Edison people from America and ready to build his motor and to find investors. Concurrently, he was getting paid for the experience. Paris in the 1880s was a center of modern fashion: men in their cutaway coats and silk top hats, women with braided hair, in long frilled dresses with bustles, and wealthy tourists ready to take back the latest fineries to their respective nations. Tesla was met by Ferenc’s brother Tivadar Puskas, a hard driver but also a man known to talk in “air balloons.”2 Tesla, whose head could also soar into the clouds, had met a powerful ally. Mindful of the need for secrecy, they discussed strategies for approaching Charles Batchelor, manager of the newly formed Compagnie Continental Edison, with Tesla’s new motor as the young inventor was introduced to operations.