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Great as are the past achievements, the future holds out more glorious promise... The day is not distant when the very planet which gave [man] birth will tremble at the sound of his voice; he will make the sun his slave... he will command the wild elements; he will push on and on from great to greater deeds until with his intelligence and force he will reach out to spheres beyond the terrestrial.(Modern Electrics 1912)


Introduction

A new millenium is time for reflection as well as anticipation. For EEs it's a good time to reflect on the important technologies of the 20th century that won't accompany us to the twenty-first. The phonograph is already gone from our lives, replaced by CDs. Movie watching today is more frequently by television than at the theater, and both movies and television are going digital. (The Phantom Menace recently saw limited release in a purely digital format). Even the incandescent light bulb is steadily being replaced with fluorescent, HID lamps (High-Intensity Discharge - the arc lamp lives!) and other, more efficient lighting technologies.

In short, many of Thomas Edison's most famous inventions - carbon microphone, phonograph, electric light, movie projector - are already obsolete or soon will be not far into the 21st century. On the other hand, fundamental electric technologies, such as 3-phase power distribution, the AC motor, wireless transmission, etc. will be with us far into the future. You may be surprised to learn that all of the latter inventions were strongly influenced by one man, a man many people today have never heard of: Nikola Tesla.

Tesla was Edison's rival at the end of the 19th century - in fact, he was more famous than the Menlo Park wizard throughout the 1890's. Temperamental genius and megalomaniacal huckster, his invention of polyphase electric power alone earned him worldwide fame and fortune. At his zenith he was an intimate of poets and scientists, industrialists and financiers. Yet Tesla died destitute, having squandered both his fortune and scientific reputation.

During his fall from notoriety to obscurity, Tesla created a legacy of genuine invention and questionable prophecy that still fascinates today. His was an age which welcomed science while continuing to embrace the mystical. His reputation resides there still, between fact and fantasy; his legacy, larger than life.

Part One - Genius
Part Two - Electrical Wizard
Part Three - Mad Scientist
Part Four - Science Fiction
 
The Early Years
Born high on an alpine plateau in the town of Smiljan in what is now Croatia (Smiljan is just west of Gospic), Nikola Tesla came to this world at night during an electrical storm. His parents were Serbian, his father a Serbian Orthodox minister and his mother from a religious family as well, but young Nikola was not destined for the priesthood.

Tesla wrote in his autobiography that from an early age he experimented with water wheels and dreamt of ways to harness the great falls at Niagara. He imagined perpetual motion machines to generate unlimited power. His mother, though illiterate, was an inventor in her own right, creating numerous household gadgets and Tesla took after her.

Both he and his elder brother Dane were said to possess photographic memories, to a degree where Tesla wrote he needed occasional help from his sisters in determining what was current and real. Both, too, had episodes of light flashes disturbing their thoughts. Whatever burden these episodes imposed later in his life, it's clear that Tesla's phenomenal memory served him well in both engineering and social settings (he spoke several languages fluently, for example).

As a boy Nikola was always in the shadow of his elder brother, thought to be the true prodigy of the Tesla family. However, Dane died tragically when Nikola was only 7. In his autobiography Tesla admits his parents never got over the loss of their promising first-born son, and their subsequent indifference to his achievements made him insecure from an early age.

Their indifference likely fired his ambition, and youthful rebellion may have directed it away from faith and towards the new age of scientific and engineering discovery. As young as 12 Tesla was practicing self-denial and developing an intense ascetic ethic. He also developed strange phobias at this age, such as an aversion to women's earrings or to touching another person's hair.

At 14, Tesla was sent to secondary school in Karlovac where he discovered a love and talent for physics and mathematics. Graduating in just three years he returned to his parents home only to meet with a cholera epidemic in Gospic. Ill for months, Tesla nearly died but recovered miraculously once his father promised he could forsake the priesthood and study engineering. He chose the Polytechnic School in Graz, Austria.

His freshman year he earned all A+'s, but so frightened his teachers with his ambition that they wrote to Nikola's father fearing for his health. His sophomore year would prove a turning point for Tesla and the world. During a demonstration of a DC dynamo, Tesla took note of the sparks that flew from the commutator brushes and remarked that it should be possible to devise a motor that operated on AC power and without the need for a commutator. His professor took pains to upbrade him in front of the class, and the humiliation launched Tesla on his quest for a commutatorless motor.

Distracted by this quest and a new addiction to gambling, Tesla failed his exams the third year and left the Polytechnic School, never to return. Through self-discipline he overcame his problem with gambling and resumed his studies the next year, auditing classes at the University of Prague. In need of a job, he next moved to Budapest and became a repairman for the American Telephone Company where he learned the practical art of electrical engineering. Monomaniacal in his quest for the brushless motor, he soon suffered a breakdown with clear neurological symptoms, including hypersensitivity to light and sound.

Part One - Genius

One of Tesla's legitimate accomplishments was the invention of a practical AC motor. At the time it was considered an impossibility and its advent nearly as significant as that of the steam engine which it would widely replace. Tesla's motor signaled the end of the Age of Steam and the dawn of a new Age of Electricity.

Invention of the Polyphase AC Motor (1882)

 
Tesla two-phase motor - generator

The inner magnet or iron core rotor follows the rotating field created in the four surrounding electromagnets (stator) by the two-phase AC generator at right. (Click on image to view patent)
A wire loop rotating between two magnetic poles forms a simple electrical generator and naturally produces an alternating current. The production of direct current is more complicated and requires the use of less reliable switching contacts called commutators. In addition, the invention of the closed-core transformer in the mid-1880's would make power distribution more practical with AC than DC. (Review AC fundamentals here). But in Tesla's day there was as yet no way to make AC do anything beyond lighting bulbs. Without a practical AC motor, we might still be using the Edison DC system today.

Since technical school, Tesla had been obsessed with the idea of a commutator-less motor. In his autobiography, Tesla claims that the solution to this problem appeared during a breakdown and in a literal flash of insight. From childhood experience we can all imagine a motor constructed of an inner magnet with poles perpendicular to the axle and surrounded by a second horseshoe magnet mounted to an independent axle. Turning one magnet causes the other to follow by simple attraction. Tesla's insight was to replace the outer magnet with two sets of stationary electromagnets, each supplied with alternating current from sources 90 degrees out of phase. The phase difference creates a rotating field that the inner rotor follows. Tesla had conceived the synchronous AC motor.

Tesla's insight would ultimately make the advantages of AC power usable by industry, with tremendous improvements in the cost and reliability of electricity. But he could convince no one of this at the time. Though the advantages of AC for power transmission were well known and many people were impressed with Tesla himself, he found himself unable to raise the capital to start a company to manufacture his new motor / generator. He went instead to work in the Paris office of a company that used the Edison system.
 

Working for Edison

While in Paris, Tesla was introduced to Charles Batchelor, one of Edison's inner circle. Impressed, he gave Tesla a letter of introduction and encouraged him to set sail for America. Tesla came to America in 1884, the same year as the Statue of Liberty and one year after the Brooklyn Bridge opened. Arriving in New York with nothing but spare change and the clothes on his back, he presented himself and Batchelor's letter of introduction to Edison at his laboratory in Menlo Park. Edison was uninterested in Tesla's plans for AC, but was always looking for another repairmen to keep his generators running smoothly. Tesla soon impressed even the indefatigable Edison by working through the night to have a ship's generators ready for departure the next morning.

The two men could otherwise have hardly been of more different temperaments, however. Edison, of 99% perspiration fame, was a fanatical, slightly uncouth experimentalist, whereas Tesla was cultured, educated in electrical theory, soft spoken and fluid in several languages. He was also perhaps a little naive.

By his own account, Tesla worked hard for Edison and his DC generating system, creating several patented improvements for the Menlo Park Wizard. He proposed additional revisions and enhancements to the Edison dynamo design and asked what they would be worth. "$50,000", was Edison's reply (at least $1M dollars today). Tesla redoubled his efforts and delivered as promised. When he presented his case for payment, though, Edison told him that he just didn't understand American humor and offerred him a modest raise instead.
 

Tesla Electric and the Induction Motor

Tesla felt cheated and left Edison to form his first company, Tesla Electric Light and Manufacturing Company to manufacture an improved arc lamp of his own design. Badgering his investors to support development of an AC motor, he soon found himself forced out of his own company and spent the winter of 1886/7 digging ditches.

The first two-phase rotating field patents
More two-phase rotating field patents
System including a transformer
Regulator for two-phase AC generator
Single-phase and other motors
Some of Tesla's AC patents
It's unclear precisely when Tesla conceived of the induction motor - he always claimed for himself the entire rotating field principal - but it's possible he discovered it by accident. The basic synchronous motor has a serious disadvantage in that the generator must be stopped and started in order to achieve a smooth startup or shutdown of the motor. This is because the motor always wants to be in precise phase with the generator. If you were to try to start the motor by simply flipping a switch connecting it to the AC mains it would shudder violently attempting to accelerate its load to speed in a single cycle. This makes the motor all but unusable with the kind of distribution we know today.

There are, however, several obvious permutations of the basic synchronous design. One is to replace the rotor magnet with a solid iron rotor and use the iron's ferromagnetic property to generate torque. This is called a reluctance motor. The second possibility is to replace the rotor magnet with an electromagnet powered by battery or, better still, by a small DC generator attached to the same shaft as the primary AC motor. This is referred to as a self-excited synchronous motor.

Experiment with our three-phase induction motor applet!
An interesting thing happens, though, if you remove the battery and short the winding ends together: the motor still runs! (Though weakly) This is because the rotating field induces eddy currents in the armature and those currents generate a force that powers the motor. Better still, the motor starts and stops smoothly and there are no commutators! This is the invention that would make Tesla world-famous: the induction motor.

By demonstrating the ability of a rotating field to spin up a metallic egg placed within its confines, Tesla succeeded in convincing new investors that his new motor offerred a credible alternative to those using DC. Forming the new Tesla Electric Company, he worked feverishly from 1887 onwards filing a wave of patents covering every facet of generation, distribution and use in 2 through N phases. The material he submitted was so unprecedented that the US Patent Office granted his claims in short order.

 

Westinghouse and the War of the Currents

An 1895 Westinghouse 3-phase induction motor (Cassier's)
George Westinghouse, inventor of the air brake and a rival of Edison's, was looking for a way to break Edison's grip on electric power. In 1890 Westinghouse had installed a 4kV single-phase system to Portland from the Willamette Falls for street lighting. Westinghouse eagerly acquired Tesla's patents and the first Westinghouse-Tesla system was installed at a Colorado mine in 1891.

Battle lines were drawn. Edison was already working hard to publicize safety concerns with the new AC system, much as he had done in his battles with the gas light companies years earlier. In addition to using the bully pulpit of his celebrity to decry its dangers, Edison helped fund the creation of the AC-based electric chair. It was rumored Westinghouse contributed to the defense fund of its first victim. There followed a short competition between the two camps in the electrocution of convicts and small animals.

Westinghouse was a shrewd promoter and meanwhile underbid Edison for rights to wire the Columbian Exposition (Chicago World's Fair) of 1893 using the Tesla system. This exposition, entirely lit by AC and with demonstrations of Tesla's motors (and without mass electrocution of the visiting public!) proved a tremendous success and a turning point in the War of the Currents.


Niagara Falls: Mecca for EEs, if Mecca had casino gambling and a carnival atmosphere. Click on the image or here for more about hydroelectric history at the Falls.

For many years, study had been given to the harnessing of the tremendous power available at Niagara Falls. At the time, the Niagara Power Commission was studying about a dozen proposals for deliver of energy to Buffalo, some 23 miles distant. More than half the proposals were electrical, including a 16kV DC system. DC dynamos had been used at the falls for more than a decade. There were also proposals for hydraulic and mechanical systems. At one point, a pneumatic system proposed by Westinghouse was the leading candidate! (The idea would have been to run a high pressure air pipe and receive the power in Buffalo using almost unmodified steam engines) But Westinghouse and Tesla's triumph in Chicago led to a contract later that year for the first two AC generators at the Edward Dean Adams power station.



  
Even today, Niagara supplies a large percentage of the electric power of New York and Ontario
Adams was an associate of J. P. Morgan (Edison's financier) and a director of Edison Illuminating. Their choice of the Westinghouse system for Niagara was the Edison system's Waterloo. They chose Westinghouse even over a similar GE proposal (Edison's company) to use polyphase AC power, GE having acquired licenses to the Tesla system.

The triumph of AC made George Westinghouse even more wealthy and Tesla comfortable. Tesla Electric sold the patents for about $250,000. Tesla would have made at least 10 times that amount in royalties except he renegotiated with Westinghouse when the latter was financially pressed. A pity, since Tesla would become increasingly impoverished in the following years...

Footnote: Westinghouse Electric is no more. After acquiring CBS, the company began divesting itself of all industrial enterprises in 1997, then changed its name to CBS Corporation. The fossil fuels generation business is now part of Siemens; nuclear power generation was sold to British Nuclear Fuels; large industrial motor manufacturing was acquired by TECO (Taiwan) with smaller motors becoming a part of Reliance Electric (a division of Rockwell Automation).


Continue with Part Two, Electrical Wizard



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