War of currents: Tesla vs Edison

10/12/2012 3:04 PM EDT

Nomenclature please,
If it makes DC, it’s a generator.
If it makes AC, it’s an alternator.
All this is especially pertinent here, as it’s the attributes of the alternator
that makes Tesla’s invention so valuable.
As well as the ability to run AC through transformers, consider
for a moment the brush life of alternators compared to generators.
In a generator, all the current passes through the commutator.
In an alternator, it’s just the field current, and the brushes see no segments, just
continuous slip rings. Tesla saved us from very frequent brush replacement,
and very hot running brushes.

10/12/2012 5:22 PM EDT

Alternator is just a made up name for an AC generator.

10/14/2012 7:54 PM EDT

Of course "alternator " is a made up name. Prior to that time the AC generator was not very common, nor used. So at the creation of a new device where the power came from the stator instead of the rotor, it did need a new name. Yes, it is indeed an AC generator, but it's name is alternator.
The beauty of AC power is indeed that the voltage is easily adjusted using transformers, and also that AC motors are more efficient and need much less maintenance. While changing brushes on a small motor is not a hard task, changing brushes on a larger motor is a bigger job indeed. One more consideration is the sealed unit refrigeration compressor. IT would not be workable with a brush-type of DC motor, since these compressors are welded shut when manufactured.
So there you have the two biggest advantages of using AC for power transmission. DC does have some places where it was the best choice, but even those places are fewer now.

10/15/2012 1:48 PM EDT

Simplified maintenance on power generators is nothing compared with the ability to efficiently transmit power over long lines at high voltage (and low current) that polyphase AC gives you.

Westinghouse ended up wealthy and Tesla died poor. Like any artist only Tesla's creations that made people rich were considered valuable. As an inventive person, he had little intrinsic value.

10/15/2012 3:09 PM EDT

Now it's a "war" of currents? Back then they just called it the "battle" of the currents. Tesla still has the biggest fan club of any scientist, so I'm sure they'll add lots of details, but here are few others.

Tesla was supposed to get a royalty of something like 3 cents/kWH for all electricity generated by the machines he invented. After a long court battle, Westinghouse managed to break that deal. Had Westinghouse been held to it, Tesla would have died the richer man.

Edison demonstrated the dangers of AC by publicly electrocuting (a word Edison coined) everything from cats to elephants (you can watch the unfortunate elephant on YouTube), and persuaded the state of New York to "electrocute" condemned prisoners (with AC, of course) at Sing Sing.

10/15/2012 3:10 PM EDT

I wouldn't feel too sorry for Tesla dying poor. None of us get out alive and he didn't get taken advantage of other than with Edison. Tesla was a genius and Westinghouse recognized it. He made Tesla a very wealthy man as well as himself but Tesla spent his fortune. A sympathetic writer questioned him almost indignantly near his death. He was quoted as saying something similar to ... In my lifetime, I have amassed and spent two entire fortunes ..... can you say as much.

While Edison's inventions are now outdated like the record player, Dynamo, and incandescent light bulb , many of Tesla's still remain. The Niagara Falls generations system, Turbines, light communication (CD's anyone), ...etc. We still use them. Flourescent lights in houses with voltage fields were a highlight in his lab.


Nikola, you lived well ......

10/15/2012 3:24 PM EDT

I'd like to mention the name of Charles Steinmetz, the cigar smoking German mathematician who understood the math behind "polyphase." I don't think that Tesla really understood the math. I'm sure that Westinghouse didn't understand how it worked.. and Edison could never figure out how a voltage that was + 50% of the time and - 50% of the time produced anything more than 0.

10/17/2012 2:12 AM EDT

"Tesla vs Edison" makes no historical sense. Teslas' own autobiographical articles written in the Electrical Experimenter in 1919 show great respect for Edison and correspondence between the two men from the period indicates no hostility whatsoever. It was Westinghouse, Tesla's one-time employer (and then foe), who was once Edison's clearest rival in the 1880s.

Thomas Edison left the lighting and power business after being effectively ousted from the electric company he had founded. On February 5, 1892 there was a forced merger of the Edison General Electric company with its rival AC proponent Thompson-Houston company, both financed by J.P. Morgan, which formed the General Electric corporation we still have today. Edison immediately resigned from the new GE board and never worked in the power and lighting business or any of its technologies again for the rest of his life. GE, however, continued to control the original Edison patents until they expired. Most of Steve Taranovich's curated article is about events that Tesla participated in during the decade after the very short-lived War of the Currents which peaked between 1886 and about 1891. The "war" was already showing signs of winding down when the pre-merger Edison companies optioned licenses on the European Z.B.D. AC system in 1886. EGE was out of the power business before exercising the options.

If anyone wants to know additional details about the history of AC power I'll post more about the Chicago Exposition of 1893 and the Niagara Falls power station.

10/19/2012 2:59 PM EDT

Both men were geniuses in the own right. With early 19th and 20th century technology, AC transmission made sense. In the late 20th century and now in the 21st century this case cannot be made so easily. There are more efficient ways of transferring DC current over greater distances. Since all modern electronics/semiconductors use DC then think how much energy could be saved from eliminating the AC to DC conversion losses.

10/23/2012 8:49 AM EDT

One of the interesting stories I was told about the rivalry between Edison's DC system and Westinghouse's AC was the electric chair was created to show people how dangerous AC was. We still adopted AC and the chair entered into widespread use.