Category: Engineering

The Tesla II post started looking at the material in Tesla: Inventor of the Electrical Age, by Bernard Carlson. Summary: Tesla made bank with his AC motor and then Tesla got famous as a showman in the pre-TV age.

The book goes on to explain that Tesla was never successful after that. He never understood Katherine Clerk Maxwell’s equations and therefore kept trying to run everything through the Earth (which turns out to be quite effective at grounding out signals!):

Of course, in many modern applications of radio—such as FM or communicating with aircraft—the transmitter and receiver circuits do not need to be grounded. In insisting on a complete circuit through the Earth and returning through the atmosphere, Tesla reveals here that his thinking was based more on nineteenth-century practices in power and telegraphic engineering (which emphasized complete circuits) and not on the electromagnetic theory then being developed by the Maxwellians (see Chapter 6) that is widely accepted today. Thinking like a maverick has advantages and disadvantages.

Tesla believed that he would not need to pump huge amounts of electrical energy into the earth; only a small amount was needed, at the right frequency, to serve as the trigger, and resonance would do the rest. With the whole Earth pulsing like his metaphorical football, Tesla was confident that he could annihilate distance and send power and messages around the world.

He not only believed this, he acted on his belief:

Leaving Chicago by train, Tesla arrived in Colorado Springs on 18 May 1899. At his hotel, the Alta Vista, he was immediately accosted by a reporter who asked him about his plans. “I propose to send a message from Pike’s Peak to Paris,” Tesla boldly replied.

… he devised a telescoping mast that could hoist a thirty-inch copper-covered ball to a height of 142 feet. To stabilize the mast, Tesla added a twenty-five-foot tower to the roof of the station.

Under Tesla’s direction, Lowenstein and Gregg built an enormous magnifying transmitter. In the station’s main room, they constructed a circular wooden wall about six feet high and 49.25 feet in diameter. Around the top of this wall they wound two turns of thick cable in order to create the primary winding of the transmitter. In the center of the room they built the secondary coil using a hundred turns of finer wire. One end of this secondary coil could be connected to either a spherical terminal inside the laboratory or the copper ball atop the mast while the other end was grounded. To provide AC to the transmitter, Tesla tapped into the streetcar line that stopped just at the edge of the Knob Hill prairie. He stepped up this 500-volt current by employing a 50-kilowatt Westinghouse transformer that he rewound so that it converted the incoming current to 20,000 or 40,000 volts. The transformer was connected to a large bank of capacitors that were automatically interrupted (and hence discharged) by a motorized breakwheel. Rounding out the equipment were several large coils that could be moved around the space between the secondary and the primary.

Tesla was able to detect signals from his high-voltage high-power apparatus from a short distance away. He did not bother to check whether the signal would be attenuated with distance.

Over the next few months, Tesla conducted additional tests to verify that his magnifying transmitter was sending currents into the ground and that they could be detected. In August he tried “arrangements for telegraphy,” finding that “[t]he apparatus responded freely to [a] small pocket coil at a distance of several feet with no capacity attached and no adjusted circuit. Consequently will go at great distance.” A few weeks later, he took a receiver outside and connected it to an underground water pipe; at 250 feet from the station, he drew one-inch sparks, and at 400 feet he got half-inch sparks. On 11 September 1900, Tesla carried a receiver a mile away from the station, to nearby Prospect Lake, where he was able to measure that the magnifying transmitter was operating with a wavelength of about 4,000 feet.

This lack of witnessed distance tests can be explained on two levels: the theoretical and the personal. From a theoretical standpoint, Tesla did not believe that such tests were necessary. Tesla had decided that stationary waves in the earth, unlike ordinary Hertzian or light waves, did not lose energy as they propagated; consequently, if they could be detected a short distance from the transmitter, these waves could be detected at any distance. Likewise, Tesla also thought that in the return circuit through the atmosphere the process of conduction was extremely efficient and that there would be minimal losses. If there were no losses as the waves traveled from the transmitter to the receiver and back again, then any test detecting the waves—no matter how short the distance—was sufficient for Tesla. Hence he concluded that “communication without wires to any point of the globe is practicable … [and] would need no demonstration.”

Tesla conceived impractical ideas for radio-controlled military attack boats that earned scorn.

Tesla might have done well in San Francisco: “Though we may never know exactly why Tesla never married, the existing sources suggest several possible explanations. The first is, quite simply, that Tesla was more attracted to men than women.”

Why didn’t he invent the rainbow flag, then? “… since sexual degeneracy, like poverty, was viewed as proof that the poor were inferior, middle-class individuals were careful not to reveal anything that could be construed as unusual about their sexual conduct.”

How about mental health?

Tesla’s way through the mountain was electrotherapy. During his earliest work with high-frequency AC, Tesla had noted how such currents affected the body, and during his spectacular demonstrations, he may have observed how shocks altered his mood. Moreover, there was a tradition in popular medicine in mid-nineteenth-century America of using electric shocks from Ruhmkorff coils to treat a variety of ailments; Elihu Thomson’s father, for instance, took shocks in the 1860s as a medical treatment. Over the next few months Tesla gave himself regular shocks, probably using one of his oscillating coils, in order to keep “from sinking into a state of melancholia.” “I was so blue and discouraged in those days,” he later told a reporter, “that I don’t believe I could have borne up but for the regular electric treatment which I administered to myself. You see, electricity puts into the tired body just what it most needs—life force, nerve force. It’s a great doctor, I can tell you, perhaps the greatest of all doctors.”

In other health news, Tesla experimented with X-rays and exposed himself to what would be criminal levels of radiation: “both he and his assistants soon experienced eyestrain, headaches, and burns on the skin of their hands.” Yet he lived to 86!

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Yesterday’s post was about Nikola Tesla as he saw himself. I also read Tesla: Inventor of the Electrical Age, by Bernard Carlson, a professor with a “Ph.D. in the history and sociology of science”.

The book is weak on explaining science and engineering. The figures are cut and pasted from patent applications of the late 19th century and they are not great for learning Electricity and Magnetism.

The publishers also gave the book a title that the body text contradicts. It seems to have been European scientists who invented the electrical age, not Tesla!

Among these scientists was Hans Christian Oersted, who in 1820 discovered a relationship between electricity and magnetism. Oersted connected a wire to a Voltaic pile and then placed a magnetic compass under the wire. To Oersted’s amazement, the compass needle was deflected only when he connected or disconnected the wire from the pile. Oersted’s experiments were repeated by André-Marie Ampere, who established that it was a flow of charge—a current—that was interacting with the magnetism of the needle and causing motion.

In 1831, Michael Faraday answered this question. Using a donut-shaped coil of wire and a bar magnet, Faraday demonstrated the laws of electromagnetic induction.

Faraday further realized the significance of Oersted’s observation that the compass needle was deflected only when the current was turned on or off; when the current was passing steadily through the wire, there was no deflection. Faraday hypothesized that both the magnet and the electric coil were each surrounded by an electromagnetic field (often depicted as a series of force lines) and that current or motion was produced when one of these fields was changing. When one turned the current on or off in Oersted’s wire, one energized or de-energized the field surrounding the wire, and this change interacted with the magnetic field surrounding the compass needle, causing the needle to swing. As we shall see, this realization that a changing field can induce a current or produce motion was essential for Tesla’s work on motors.

The author also credits Heinrich Hertz with the fundamentals behind radio communication.

What if we had to rely on the work of European engineers?

In Europe, though, AC was not forgotten, and inventors there improved the transformer; by winding two different coils on a single iron core, they found they could raise or lower the voltage of alternating current, and they quickly started using this new device in a variety of ways. For instance, in London in 1883, Lucien Gaulard and John Gibbs used one of the first transformers to connect both arc and different incandescent lights in series to a single large generator.29 About the same time in Budapest, the engineers Tesla had met at Ganz and Company—Zipernowski, Bláthy, and Déri (ZBD)—saw AC as a way of developing an incandescent lighting system that could serve a wider area. By having their generator produce high-voltage AC, they found they could distribute power over longer distances using small copper wires. To protect customers from the high voltage, they used a transformer to step down the voltage before the current came into homes and shops. Within a few years, the ZBD system was being used to light several European cities. Both the Gaulard and Gibbs and ZBD systems employed single-phase AC since that was all that was needed to secure the desired voltage change.

In other words, if no Americans had ever tinkered in this area, we’d have exactly the same system delivering power to our homes and offices.

How about the AC motor itself?

This brings us to Tesla’s third insight in the park. Based on his extensive mental engineering, Tesla had a hunch that somehow one or more alternating currents could be used to create a rotating magnetic field. If so, his thinking would have paralleled that of an English physicist, Walter Baily, who reported in 1879 how he had used two electric currents to cause Arago’s wheel to rotate. Instead of a horseshoe magnet, Baily placed four electromagnets underneath his copper disk (see Figure 2.9). Baily linked the coils in series, joining one with the other diagonally across from it. He then connected each pair of electromagnets to a rotating switch that controlled the current delivered from two separate batteries to the pairs of electromagnets. As Baily rotated his switch, the electromagnets were sequentially energized to become either north or south magnetic poles, with the effect that the magnetic field underneath the copper disk rotated. As a scientist, Baily seems to have been satisfied to know that electric currents could be used to turn Arago’s wheel, and he regarded his motor as a scientific toy.

1884 was a year in which no human being was illegal and Tesla emigrated to the U.S.:

Years later he recalled that process of formally entering the United States consisted of a clerk barking at him, “Kiss the Bible. Twenty cents!” Having lived in the cosmopolitan cities of Prague, Budapest, and Paris, Tesla was initially shocked by the crudeness and vulgarity of America. As he wrote in his autobiography, “What I had left was beautiful, artistic, and fascinating in every way; what I saw here was machined, rough, and unattractive. A burly policeman was twirling his stick which looked to me as big as a log. I approached him politely, with the request to direct me [to an address]. ‘Six blocks down, then to the left,’ he said, with murder in his eyes. ‘Is this America?’ I asked myself in painful surprise. ‘It is a century behind Europe in civilization.’

Tesla was quickly successful, selling patents on AC motors to Westinghouse in 1888 and earning roughly $90,000 for himself. What would $90k have been worth?

In late September, Tesla switched from the Astor House to the Gerlach Hotel on 27th Street, between Broadway and Sixth Avenue. Built in 1888 at a cost of $1 million, the Gerlach was an imposing eleven-story fireproof building that featured elevators, electric lights, and several sumptuous dining rooms.

I.e., Tesla earned enough to fund construction of one entire floor of a massive hotel in Manhattan.

He was a fantastic showman:

To help the audience appreciate the full potential of high-frequency AC for electric lighting, Tesla offered a breathtaking demonstration (Figure 7.2). Two large zinc sheets were suspended from the ceiling about fifteen feet from each other and connected to the oscillating transformer. With the auditorium lights dimmed, Tesla took a long gas-filled tube in each hand and stepped between the two sheets. As he waved the slender tubes, they glowed, charged by an electrostatic field set up between the plates. As Tesla explained, high-frequency current now made it possible to have electric lighting without wires, to have lamps that could be moved freely around a room.

From London, Tesla traveled on to Paris and booked a room in the Hotel de la Paix. On 19 February he gave a lecture before the Société de Physique and the Société International des Electriciens (Figure 8.3). Finding his demonstrations highly persuasive, the French electrician Édouard Hospitalier observed, “The young scientist is … almost as a prophet. He introduces so much warmth and sincerity into his explanations and experiments that faith wins us, and despite ourselves, we believe that we are witnesses of the dawn of a nearby revolution in the present processes of illumination.” Just as in London, Tesla’s performance generated a great deal of excitement and praise. “The French papers this week are full of Mr. Tesla and his brilliant experiments,” reported the Electrical Review. “No man in our age has achieved such a universal scientific reputation in a single stride as this gifted young electrical engineer.”

What did it cost to attend?

In St. Louis, Tesla lectured in the Exhibition Theater, which seated four thousand, but the hall was packed to suffocation as another several thousand people crowded in, most of whom came hoping to see Tesla’s spectacular demonstrations. The demand for seats was so great that tickets were being scalped outside the hall for three to five dollars.

We forget how unstable the U.S. economy was back then. The Panic of 1893 nearly put the new electric companies out of business and certainly wiped out a lot of shareholders even when the companies continued to operate.

The next post will talk about Tesla’s attempts to come up with a Second Act.

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One doesn’t learn much history in Electrical Engineering skool. I had a dim perception of Nikola Tesla as someone who turn Katherine Clerk Maxwell‘s equations into practical AC generators and AC motors. So it seemed to make sense that an electric car company would be named after Mr. Tesla.

During my recent trip to China, I decided to read up on the pioneers of the technology that has made China the modern industrial powerhouse (so to speak) that it is.

I started with My Inventions, The Autobiography of Nikola Tesla. Tesla wrote the book in 1919 at the age of 63 (he would die in 1943, in poverty and debt, in the New Yorker Hotel at age 86). He is enthusiastic about invention:

The progressive development of man is vitally dependent on invention. It is the most important product of his creative brain. Its ultimate purpose is the complete mastery of mind over the material world, the harnessing of the forces of nature to human needs.

Tesla implied that his personality was inherited:

My mother was an inventor of the first order and would, I believe, have achieved great things had she not been so remote from modern life and its multi fold opportunities. She invented and constructed all kinds of tools and devices and wove the finest designs from thread which was spun by her. She even planted seeds, raised the plants and separated the fibbers herself. She worked indefatigably, from break of day till late at night, and most of the wearing apparel and furnishings of the home were the product of her hands. When

Very quickly the delusions begin

My sight and hearing were always extraordinary. I could clearly discern objects in the distance when others saw no trace of them. Several times in my boyhood I saved the houses of our neighbors from fire by hearing the faint crackling sounds which did not disturb their sleep, and calling for help. In 1899, when I was past forty and carrying on my experiments in Colorado, I could hear very distinctly thunderclaps at a distance of 550 miles.

In Budapest I could hear the ticking of a watch with three rooms between me and the timepiece. A fly alighting on a table in the room would cause a dull thud in my ear. A carriage passing at a distance of a few miles fairly shook my whole body.

Isn’t it a good working definition of “delusional” to hear things that nobody else hears?

Bad news for Tesla shareholders:

If my memory serves me right, it was in November, 1890, that I performed a laboratory experiment which was one of the most extraordinary and spectacular ever recorded in the annals of Science. In investigating the behavior of high frequency currents, I had satisfied myself that an electric field of sufficient intensity could be produced in a room to light up electrode less vacuum tubes. Accordingly, a transformer was built to test the theory and the first trial proved a marvelous success. It is difficult to appreciate what those strange phenomena meant at the time. We crave for new sensations, but soon be come indifferent to them. The wonders of yesterday are today common occurrences.

(I still like Dog Mode, though, having asked for it back in 2003!)

Speaking of Dog, Tesla wanted to compete with God:

One day, as I was roaming the mountains, I sought shelter from an approaching storm. The sky became overhung with heavy clouds, but somehow the rain was delayed until, all of a sudden, there was a lightening flash and a few moments after, a deluge. This observation set me thinking. It was manifest that the two phenomena were closely related, as cause and effect, and a little reflection led me to the conclusion that the electrical energy involved in the precipitation of the water was inconsiderable, the function of the lightening being much like that of a sensitive trigger. Here was a stupendous possibility of achievement. If we could produce electric effects of the required quality, this whole planet and the conditions of existence on it could be transformed. The sun raises the water of the oceans and winds drive it to distant regions where it remains in a state of most delicate balance. If it were in our power to upset it when and wherever desired, this might life sustaining stream could be at will controlled. We could irrigate arid deserts, create lakes and rivers, and provide motive power in unlimited amounts. This would be the most efficient way of harnessing the sun to the uses of man. The consummation depended on our ability to develop electric forces of the order of those in nature.

Though he also believed in God:

[World] Peace can only come as a natural consequence of universal enlightenment and merging of races, and we are still far from this blissful realization, because few indeed, will admit the reality that God made man in His image in which case all earth men are alike. There is in fact but one race, of many colors. Christ is but one person, yet he is of all people, so why do some people think themselves better than some other people?

Tesla was not daunted by failure:

I have refrained from publicly expressing myself on this subject before, as it seemed improper to dwell on personal matters while all the world was in dire trouble. I would add further, in view of various rumors which have reached me, that Mr. J. Pierpont Morgan did not interest himself with me in a business way, but in the same large spirit in which he has assisted many other pioneers. He carried out his generous promise to the letter and it would have been most unreasonable to expect from him anything more. He had the highest regard for my attainments and gave me every evidence of his complete faith in my ability to ultimately achieve what I had set out to do. I am unwilling to accord to some small-minded and jealous individuals the satisfaction of having thwarted my efforts. These men are to me nothing more than microbes of a nasty disease. My project was retarded by laws of nature. The world was not prepared for it. It was too far ahead of time, but the same laws will prevail in the end and make it a triumphal success.

Tesla was an isolationist and would have to agree to disagree with Greta Thunberg:

As I view the world of today, in the light of the gigantic struggle we have witnessed, I am filled with conviction that the interests of humanity would be best served if the United States remained true to its traditions, true to God whom it pretends to believe, and kept out of “entangling alliances.” Situated as it is, geographically remote from the theaters of impending conflicts, without incentive to territorial aggrandizement, with inexhaustible resources and immense population thoroughly imbued with the spirit of liberty and right, this country is placed in a unique and privileged position. It is thus able to exert, independently, its colossal strength and moral force to the benefit of all, more judiciously and effectively, than as a member of a league.

He was interested in aviation:

As stated on a previous occasion, when I was a student at college I conceived a flying machine quite unlike the present ones. The underlying principle was sound, but could not be carried into practice for want of a prime-mover of sufficiently great activity. In recent years, I have successfully solved this problem and am now planning aerial machines devoid of sustaining planes, ailerons, propellers, and other external attachments, which will be capable of immense speeds and are very likely to furnish powerful arguments for peace in the near future. Such a machine, sustained and propelled “entirely by reaction,” is shown on one of the pages of my lectures, and is supposed to be controlled either mechanically, or by wireless energy. By installing proper plants, it will be practicable to “project a missile of this kind into the air and drop it” almost on the very spot designated, which may be thousands of miles away.

He also wanted to do AI and self-driving cars!

But we are not going to stop at this. Telautomats will be ultimately produced, capable of acting as if possessed of their own intelligence, and their advent will create a revolution. As early as 1898, I proposed to representatives of a large manufacturing concern the construction and public exhibition of an automobile carriage which, left to itself, would perform a great variety of operations involving something akin to judgment. But my proposal was deemed chimerical at the time and nothing came of it.

That’s Tesla in his own words. The next post will have some links from a biography.

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We recently made it through the Northwest Passage on the MS Roald Amundsen, a diesel-hybrid cruise ship.

What could be dumber than putting a huge bank of batteries into a machine that needs to be generating power constantly, e.g., to run lights, water desalination, air conditioning, sewage treatment, etc.?

At a talk by the ship’s chief engineer, Jonny Johnsen, we learned that this may make good engineering sense. The key insight is that it is most efficient to run any of the four diesel engines at 80 percent power. Although the ship can sail for 30 minutes at 14 knots on the battery alone, that’s not the point of the batteries. The idea is to have a power reserve that does not require keeping an extra engine at idle. If the ship needs a sudden burst of power for maneuvering, the power comes from the battery while perhaps just a single engine is running. After the demand is gone, the engine keeps running at 80 percent to recharge the batteries.

The batteries enable the crew to run just one engine without fearing a blackout (though maybe California-based passengers would feel right at home in such an event?).

The engines are reasonably efficient to begin with, over 50 percent before heat recovery, which is used to heat water, heat the cabins, heat the pool/hot tubs, and help with desalinization. But having a big bank of batteries makes the overall trip more efficient. The engineer said that he expected we would use 300,000 liters of diesel for the trip from Greenland to Nome, Alaska. Divided by the 472 passengers who were on board, that’s only 169 gallons in a three-week period. An SUV-owning American who liked to drive a lot might consume more!

More engineering facts:

• the ship produces 156 cubic meters/day of fresh water via two RO systems (force seawater through a membrane and dump the brine overboard); 300,000 liters per day
• the ship does not anchor; computers, GPS, swiveling propellers (2) and bow thrusters (2) maintain station (as in https://philip.greenspun.com/blog/2019/08/21/movie-the-last-breath/ )
• for NOx emissions control, the engines use the same “add blue” urea as European diesel cars
• the ship has a conventional anti-roll stabilizer system
• the ship is rated Polar Class 6, which means we could go through 70 cm of level ice

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