Tesla Vs. Edison

The phrase "Tesla vs. Edison" conjures up images of battling titans, mad scientists, from a bygone age. We can easily picture the two of them facing off, backed by glowing corona with lightning bolts emitting from their hands. The reality is a little different though. Their main point of contention was Tesla's passion for AC vs. Edison's drive to create DC power systems to power his lights. Their personalities also differed in many ways, the most relevant one here being their vastly different approaches to research. Here, then, is the story of their rivalry.

Nikola Tesla's passion for AC started indirectly in 1876 while studying physics, mathematics and mechanics at the Austrian Polytechnic School in Graz, Austria. One of his professors showed him a direct current Gramme Machine that could be used as both a motor and a dynamo. It had a wire-wound armature and a commutator where it sparked a lot. Tesla inspected it closely and told the professor that he could improve it greatly by getting rid of the commutator and using alternating current instead, though he didn't know how at the time.

For a long time, he felt he had the solution buried away in his mind but it finally surfaced in 1882 while walking in a park with a friend. He found a stick and drew a diagram of it in the dust, showing his friend how it worked as both a motor and a dynamo. It used a rotating magnetic field, rotated using two or more alternating currents out of step with each other. Tesla had come up with a true AC induction motor. According to his autobiography, "My Inventions", within two months he had "evolved virtually all the types of motors and modifications of the system which are now identified with my name."

Around the same time across the Atlantic, Thomas Edison was busy working on incandescent light bulbs. Incandescent light bulbs work by running current through a material, called the filament, heating it up until it incandesces, or glows. One of the problems in the 1800s was that the filaments didn't last long under the heat. Edison worked on solving this problem and started filing light patents in 1878. At the same time he formed the Edison Electric Light Company as a patent-holding company, one of many companies in which he had a business interest.

Once he’d come up with a commercially viable light bulb, he needed some way for his customers to power them. In 1880 he formed the Edison Illuminating Company to build electrical generating stations, starting in New York City. In 1882 he switched on the Pearl Street Station's electrical distribution system, the first of many, supplying 110 volts DC to 59 customers.

But at the same time, AC systems for arc lighting were popping up. AC systems had the advantage of being able to transmit over a longer distance with thinner wire. Using transformers, the electricity could be stepped up to high voltage but low current at the generator and then stepped down again to safer voltages near the customer.

No such good voltage conversion technology existed for DC at the time and so Edison had to keep the voltage reasonably low along the full route. This meant the current was relatively high and so the wires were thick to handle it. And to keep wire costs down, the generators had to be near the customers. That meant Edison could serve only areas with a high customer density, sometimes skipping pockets of lower density in between.

But for reasons we can only speculate about today, Edison refused to switch to using AC. Possibly this was because he may not have been able to understand the more abstract theories involved with AC, or maybe he was concerned with the high voltages involved with AC transmission, or possibly he simply had too much invested in his numerous DC stations. For whatever reason, though he did dabble in AC from time to time, outwardly Edison was staunchly against it.

While 1882 was the year Tesla had his AC epiphany as well as being the year Edison powered up the DC Pearl Street Station, it was also the year that Tesla went to work for Edison's telephone subsidiary in Paris, the Continental Edison Company. His job was basically troubleshooter for Edison power plants in France and Germany.

Tesla saw it as an opportunity to sell the company on the merits of AC but was disappointed to find that talk of AC was taboo due to Edison's dislike of even the mention of it. That didn't stop him from experimenting, though, and when going out on a job in Alsace he brought along materials and made his first AC induction motor, seeing an AC motor turning without a commutator for the first time.

In Strasbourg, the company had installed a railroad-station lighting plant. However, a large chunk of one of the station's walls had been blown out due to a short-circuit when the plant was turned on during the opening ceremony, and in the presence of German Emperor William I. The Germans were not pleased and were having second thoughts about using the lighting plant. Facing a financial loss, the company offered Tesla a bonus if he would go improve the dynamos and calm the Germans down.

Tesla managed to improve the system and placate the Germans, helped by the fact that he spoke German. But when he returned to Paris to collect his bonus his three supervisors refused to pay, instead passing the buck from one to the other. Tesla resigned and so ended his first employment with Edison.

The manager of the Strasbourg plant, Charles Batchelor, was impressed by Tesla and talked him into moving to America where he’d find more opportunities. He also gave Tesla a letter of introduction to give to Edison.

On arriving in America, Tesla quickly located Edison and gave him the letter. Tesla told him of his work in France and Germany, and then proceeded to tell him about his ideas for AC systems and how an enterprising man could make a lot of money from it. Edison stopped him and angrily said, "Hold up! Spare me that nonsense. It's dangerous. We’re set up for direct current in America. People like it, and it's all I’ll ever fool with." But overloaded with problems to solve, he set Tesla to working on one of them right away. Tesla of course solved it quickly and, sufficiently impressed, Edison kept Tesla on.

By 1885 Tesla saw ways to make Edison's DC dynamos more efficient and save him a lot of money. Edison liked the idea of saving money but realised it would be a lot of work, so he told Tesla he’d give him $50,000 if he could do it. After almost a year working on it, Tesla completed the improvements and went to Edison to find out when he’d receive the $50,000. Edison, reclining at his desk at the time, straightened up with mouth gaping and said "Tesla, you don't understand our American humor." Instead, he offered Tesla a raise of $10 on his $18 per week salary. Tesla walked out and resigned. Once again he’d been cheated while working for Edison.

After some difficulties, in 1887, along with two other men, Tesla formed the Tesla Electric Company. It was there that he began developing and patenting his AC induction motor and the rest of his polyphase system, quickly amassing a large number of patents: 40 by 1891.

The War of Currents refers to a period from the late 1880s to the early 1900s when the battle between distributing electricity via AC or DC was at its fiercest. The battle was fought primarily between the Edison Electric Light Company and George Westinghouse's Westinghouse Electric Company.

Westinghouse began his foray into AC electricity distribution in 1886 by forming the Westinghouse Electric Company. He’d already purchased the US rights to the Gaulard-Gibbs transformer and began installing distribution systems.

But he needed Tesla's exhaustive set of polyphase and induction motor patents, and in 1888, he purchased all of the relevant US ones. The two of them shared the same dream of a new energy system, as well as a dream of harnessing Niagara Falls for power generation and so Tesla went to work for Westinghouse as a consultant for $2000 per month. When Edison heard of this he was furious and at that point, the War of Currents between Edison and Westinghouse was on.

Work began on the Niagara Falls generating station in 1893 and started powering Buffalo, NY in 1896. As to whether AC or DC won the War of Currents, you need only look at our electrical distribution system today to see.

As Hackaday readers, we know it takes all kinds of personalities to make up our community. This is an area where Edison and Tesla differed greatly and often created strains on their relationships.

Tesla had a photographic memory and could simulate entire systems of working machines in his head. This caused friction between him and other engineers as, while he worked in his mind, they wanted blueprints. His approach to problem-solving was to do most of the work using theory and calculation. For this reason Edison thought of Tesla as an egghead and a theoretician.

According to Edison, ninety-nine percent of genius was "knowing things that would not work". Edison's approach to problem-solving was thus through trial and error. To do that, his Menlo Park lab famously had in stock a multitude of different chemicals and materials. Tesla once said, "If Edison had a needle to find in a haystack, he would proceed at once with the diligence of the bee to examine straw after straw until he found the object of his search."

However, we can't fault either for their different approaches, either to problem-solving or in choosing AC or DC, given the positive effects their respective accomplishments had, and still have today.

What are some of your favorite technology battles or battles of technological wizards? Some that recently came up here were the invention of the radio and the airplane. Let us know in the comments below.