The prior-art of war
The feud between Edison, Westinghouse and Tesla.
27th July 2019
Nearly 90 years after his death, Thomas Edison remains one of the world’s most well-known inventors. It may come as a shock, but – despite the 1,000 or so patents to his name - the innovation he is most famous for isn’t really one of his…
Ask anyone to name Edison’s most famous invention and most people say ‘the light bulb’, but the concept had been around for years. In fact, it originated in 1761 when Ebenezer Kinnersley found that he could heat a wire to incandescence. Then, in 1875, Henry Woodward and Mathew Evans filed for a patent— US 181,613 ‘Improvement in electric lights’. After several unsuccessful years trying to commercialise their lamp, they gave up and sold the rights to Edison in 1879.
Edison improved upon the Woodward and Evans design over several months and demonstrated the world’s first practical incandescent light bulb in late 1879. It was a defining moment in his career, which made him a household name. There was just one problem: even though he had apparently perfected a durable, safe and mass-produced form of electric light, there was no way to power it. It was as if he’d invented the iPhone before we had a mobile network.
Edison’s light bulbs needed direct current (DC) where energy flows constantly in one direction (the same way as an AA battery). So the Edison Illuminating Company was created to produce DC electricity, and Edison began working to establish DC as the standard across the whole of the United States.
The first DC power station opened in New York in September 1882 and began serving 59 customers. More stations followed, increasingly supplying power to newly connected homes and businesses, and the money started rolling in. Yet these early gains masked a serious problem — the unavoidable reality of DC’s major drawbacks.
Chiefly, DC electricity couldn’t be transmitted over long distances without losing a lot of energy. So much so that power plants could be no more than a mile away from customers, thus requiring dozens of generators and miles of valuable copper wire. Additionally, DC ran at a constant rate, which meant supplying the necessarily different voltages for domestic, commercial and industrial use would require separately installed lines – severely amplifying Edison’s business costs.
Alternating current (AC), where the flow changes direction many times a second, solved these problems; the voltage could be increased or ‘stepped up’ using a transformer, allowing the electricity to be transmitted much further than with DC, all with minimal loss. The high voltage could then be ‘stepped down’ at source to make it safe for use, and could be stepped down to any required voltage. The power plants could be larger and fewer in numbers, therefore making an AC based electricity system much cheaper to operate. On top of this, AC required less copper — another advantage AC had over DC.
Enter railroad tycoon George Westinghouse. He was an exceptionally savvy businessman and immediately recognised the limitations of a DC powered electricity grid. Westinghouse began work establishing an AC based system to rival Edison, but AC hadn’t been perfected yet and still needed some vital innovations to turn it into a fully functioning system.
Luckily for Westinghouse, there was a man who had worked them out — a brilliant Serbian mathematician and engineer called Nikola Tesla. Luckier still, Edison, even with all of his light bulbs, couldn’t see the solution right under his nose. You see, Tesla worked for Edison, at Edison Machine Works improving DC generators, and believed the future of distributing electricity lay in AC and filed multiple patents on the subject. After repeatedly trying to convince Edison to convert to AC and having his ideas rejected over and over again as ‘utterly impractical’, he left.
What Tesla lacked in capital and business know-how, Westinghouse had in abundance. He recognised Tesla’s genius and quickly offered him a job as a consultant. Westinghouse also bought Tesla’s patents for $60,000 and gave him $2.50 for each horsepower of electricity sold — all worth millions in today’s money.
And so began the ‘War of the Currents’: AC v DC. For full details and to find out who wins, you should go and see the new film starring Benedict Cumberbatch, Nicholas Hoult, Tom Holland and Michael Shannon. SPOILER ALERT: you are reading this on a machine powered by 240V, 50Hz AC.
Despite the ultimate success of his method, Tesla’s fortune was consumed in constant patent disputes and he ultimately died penniless and alone in 1943, while Edison enjoyed fame and riches until his death in 1931.
So who really won? We thought we would assess the legacies of the three men with a final showdown based on the number of patents filed by random companies bearing their names: Tesla Motors inc, Westinghouse Electronic Products, and Edison Electric Appliance Co.
And the winner is…
Tesla with 168 patent families! Edison and Westinghouse trail behind with 64 and 58, respectively. We never said this would be a fair fight, but we like to think we helped give some closure to this one.
After all this talk of AC and DC, now we can’t get Thunderstruck out of our heads. As much as we love the original, if you haven’t heard the 2Cellos cover, live at Arena di Verona, you are missing a real treat. Crank up the volume and prepare to be electrified!
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We have a lot more to say about the war of currents and patents. For information on this and any other patent information study, please visit patently.com and email us at ask@patently.com.
