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Nikola Tesla--The Man Who Lit Up the World

An Excerpt from The Geek Atlas

 
By Sara Peyton
May 28, 2009 | Comments: 13

Geek.jpgJust in time for summer vacation planning comes an exciting new travelers' guide from O'Reilly, The Geek Atlas: 128 Places Where Science & Technology Come Alive ($29.99), by John Graham-Cumming. Learn about Nikola Tesla in this excerpt from The Geek Atlas now. The excerpt includes a discussion of AC versus DC and information about the Tesla Museum in Belgrade, Serbia.

Excerpted from The Geek Atlas
Thomas Edison is the name most people associate with electric light, but the man responsible for providing the electricity to lights and every other electrical device used today is Nikola Tesla (Figure 30-1). Tesla was born to Serbian parents in what is now Croatia, and lived in Hungary and France before moving to the U.S. in 1885. It was there that Tesla became the greatest electrical experimenter since Michael Faraday (see Chapter 75) and laid the foundations for modern electricity distribution.

When Tesla moved to the U.S., he went to work in Edison's laboratory, where he redesigned Edison's DC generators and motors. He left after a disagreement about his pay, and after Edison had rebuffed Tesla's attempts to interest him in AC electricity generation.

Later, Tesla and Edison battled bitterly and publicly over AC and DC electrical power. Tesla had joined up with entrepreneur George Westinghouse to build AC power stations, while Edison was pushing DC power. Edison tried to show that AC was dangerous, and to prove it he carried out executions of dogs, cats, horses, cattle, and even an elephant using AC power.

Ultimately, Tesla was proved right: AC power is easier to generate (the generators are simpler, cheaper, and more reliable), it can be transmitted much further (DC power was limited to short distances and necessitated power stations close to consumers), and its voltage can be converted using a simple transformer.

But Tesla's inventions were not limited to AC power. Along with Marconi, he shares the honor of inventing radio (see Chapter 62), and he worked on wireless transmission of electricity, remote controls, vertical take-off and landing aircraft, directed-energy weaponry, robotics, spark plugs, and more. In all, he was awarded over 300 patents.

Nevertheless, Tesla died destitute, in room 3327 of the New Yorker Hotel in New York City. Two thousand people attended his funeral.

After his death, Tesla's nephew and heir (who was also the Yugoslav ambassador), Sava Kosanovic, arranged for Tesla's personal effects to be removed from the U.S. and returned to Yugoslavia. Today the Tesla Museum in Belgrade houses his complete collection of books, writing, and objects, as well as his cremated ashes on display in a golden sphere.

The museum explains many of Tesla's inventions, including AC power, and is the definitive place to understand Tesla's life and work.

Information about the museum and details of Tesla's life are available at http://www.tesla-museum.org/. If Serbia is too far away to visit, there's also a memorial to Tesla on the Canadian side of Niagara Falls, where Tesla's hydroelectric power plant was situated. See http://www.teslasociety.com/victoria.htm.

AC Versus DC

Direct current, or DC, is simple: it's the type of electricity that batteries supply. In a DC circuit, electricity flows in one direction only--for example, from the positive terminal of a battery through a circuit to the negative terminal. Alternating current, or AC, changes direction cyclically, typically in the form of a sine wave (Figure 30-2).

Figure 30-2. AC voltage varying with time

volt.png

AC varies in voltage from a positive maximum to a negative minimum over time. To generate AC power, a current can be induced in a pair of coils using a rotating magnet. The current varies as the magnet rotates. Since the magnet does not touch the coils, AC generators are reliable and simple. DC generators, on the other hand, require a more complex mechanism, with rotating brushes touching metal connectors that are used to change the direction of the current to keep it positive.

It's simple to change the voltage of AC using a transformer (Figure 30-3). A basic transformer consists of a pair of coils, separated either by air or, more commonly, by some ferromagnetic material such as a bar of iron. Because the AC voltage varies over time, it creates a changing magnetic field around the coil it is connected to. This magnetic field induces an AC voltage in the other coil. The ratio of the number of windings of cable in the two coils determines the change in voltage (and current) across the transformer.


Figure 30-3. An AC transformer

transformer.png

But AC's biggest advantage is in power transmission. Because AC's voltage can be increased or decreased using transformers, it's possible to choose the most appropriate voltage for a given situation (see Figure 30-4); that is, power transmission can use a very high voltage that is then reduced by a transformer before entering a home. Generators in power plants can produce power at a lower voltage than the transmission line, with the voltage being increased before transmission by another transformer.

Figure 30-4. Power transmission using AC

powertrans.png

Because the voltage can be changed so easily, AC is able to take advantage of the fact that power loss in a cable is proportional to the square of the current. By increasing the voltage (perhaps to hundreds of thousands of volts), with a corresponding decrease in current, power can be transmitted over great distances. It can then be transformed to a lower voltage (and higher current) for delivery.

AC can also be converted to DC, using a simple device called a rectifier. Small electrical appliances (like cell phones) usually operate on DC, and power adapters both convert the AC supply to a low voltage and turn it into DC.

If you enjoyed this excerpt, purchase The Geek Atlas now. and start planning your summer vacation!


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13 Comments

Nice well written article. Tesla was a pioneer far ahead of his time. One of the many people who brought electricity from being a curiosity in a laboratory to becoming a force that would transform the world.

Surely a man Much ahead of his time, Never got the credict he deserved. I am sure as time passes by, People will judge him muvh higher than a lot of his peers.




In a world of ever flowing information small errors often go unnoticed



In a world of ever flowing information small errors often go unnoticed.  Please correct the Telsa error in your preface:

 

The excerpt includes a discussion of AC versus DC and information about the Telsa Museum in Belgrade, Serbia.

@Ed, Thank you!

Tesla's nephew was Sava Kosanovic, not Sava Kosanovilatin.

@Ed and @Veso

Thank you for pointing out these errors. They are only present on this web page and are not present in the book, I just went and checked.

Tesla's name is spelt correctly and his nephew is given as Sava Kosanovic with the correct accent on the c.

John.

While AC does provide more flexibility for stepping down the power, ultra high voltage DC provides more efficient point-to-point transmission of power over long distances. The summary from http://www02.abb.com/global/gad/gad02077.nsf/lupLongContent/200B848D53152367C12572FB0046DE0B is noteworthy:

"In order to transmit bulk power over long distances (more than 500–1000 km), 800 kV HVDC is normally the most cost efficient alternative. The biggest drawback of HVDC is the high cost of tapping power along the route. A combination, where the bulk power is fed by HVDC and the power needed along the route is fed by AC seems to be the most cost effective and flexible solution. 1000 kV AC is more suitable as an overlay net to existing 400 or 500 kV AC nets in densely populated areas."

These tradeoffs are about power levels that are far higher than were being discussed during the Tesla/Edison/Westinghouse debates.

I recall reading that both ultra high voltage DC and AC will be part of planned enhancements to the US power grid (but cannot locate the article right now).

Categorically claiming the superiority of AC for power transmission is a bit of a simplification. Does The Geek Atlas provide any discussion or links to discussion of ultra-high voltage AC and DC solutions that are being deployed today?

@Phil Earnhart

Thanks for the comment. I looked in detail at whether there were any HVDC connections that were visitable and unfortunately I could not find any. There is an HVDC link between France and the UK that used to have tours on the UK side but they are no longer available.

I also looked into some in the US, but most power plants are now off limits because of "security worries".

If you or anyone knows of an interesting HVDC plant that's worth visiting please let me know via geekatlas.com. I'm working to build a possible second volume of the book and your suggestions are really welcome.

Thanks, John. I'm certain I've never seen a HVDC line.

I did write an interesting piece which included Stockbridge Dampers on transmission lines: "The Graceful Movement of Everyday Things" ( http://floatingbones.com/?p=66 ). The funny thing is that we've all looked at transmission lines a bunch of times, but few of us ever saw these little widgets to control vibrations on the lines. That's appropriate; we're usually pretty oblivious to the import of damping.

I just took a trip to the Hoover Dam. Most of the lines there double the dampers on each segment; I guess it gets very windy in that part of the country. The main arch of the Hoover Dam Bypass bridge ( hooverdambypass.org ) is currently under construction; span will be completed this fall. It's a great time to visit.


@Phil Earnhardt

That's really interesting. I'd often looked at those things and wondered what they were.

Thanks for the comment. I looked in detail at whether there were any HVDC connections that were visitable and unfortunately I could not find any. There is an HVDC link between France and the UK that used to have tours on the UK side but they are no longer available.

I also looked into some in the US, but most power plants are now off limits because of "security worries".

If you or anyone knows of an interesting HVDC plant that's worth visiting please let me know via geekatlas.com. I'm working to build a possible second volume of the book and your suggestions are really welcome.

Thank you for pointing out these errors. They are only present on this web page and are not present in the book, I just went and checked.

Tesla's name is spelt correctly and his nephew is given as Sava Kosanovic with the correct accent on the c.

John.

Tesla's nephew was Sava Kosanovic, not Sava Kosanovilatin.

 

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