Disentangling Facts From Fantasy In the World of Edison and Tesla 386
dsinc writes "Forbes' Alex Knapp writes about the Tesla idolatry and confusing his genius for godhood: 'Tesla wasn't an ignored god-hero. Thomas Edison wasn't the devil. They were both brilliant, strong-willed men who helped build our modern world. They both did great things and awful things. They were both brilliantly right about some things and just as brilliantly wrong about others. They had foibles, quirks, passions, misunderstandings and moments of wonder.'"
Irrefutable fact (Score:5, Informative)
Tesla > Edison.
Re:Go have a look at the Oatmeal's latest (Score:5, Informative)
Re:false equivalency (Score:5, Informative)
AC was much better for transmitting back then because transmitting high voltage is more efficient (less current means less copper and less resistive waste) and they had an efficient way of converting high voltage AC to low voltage AC (transformers). Efficient high voltage DC-DC voltage conversion was not something that was possible back in the day.
DC is actually more efficient for long distance high voltage transmission -- they just didn't have the technology to convert DC voltage. Now days HVDC transmission for new long distance lines is much more viable.
Re:false equivalency (Score:5, Informative)
For modern high-voltage transmission, capacitive losses matter even at 50/60Hz. HV transmission is best done as DC. The thing Tesla was right about was that with technology available back then, AC distribution was the only feasible one. It has only been in the last few decades that we have the semiconductor technology that would allow completely solid state, DC-to-DC power conversion all the way to the consumer. That would be, ultimately, the way to go. DC-to-DC converters can be quite compact compared to 50/60Hz transformers, especially when running at high frequencies. I've seen resonant converters taking in 10kV 3 phase and outputting 1.5kV DC at about 50kVA. It had PFC as well. Two people could very easily lift one up, it was probably less than 200lbs, just bulky, and the magnetics (cores) could fit in a breadbox. Try lifting up a 50kVA oil immersed transformer with same ratings -- it's half a ton, give or take.
Alas, circuit breakers for DC are significantly more complex and expensive than ones for AC, since you have an arc that needs to be quenched. They need to have a chamber that utilizes spatial gradients in pressure or temperature (due to asymmetry of the plasma chamber) to move some air around to blow the arc out. AC arcs are usually self-extinguishing, except at extreme short-circuit currents and voltages (high voltage substations and the like).
Re:false equivalency (Score:5, Informative)
Yes, and Nikola Tesla was simply wrong in promoting alternating current for about any use. If you look at modern electrical or electronic gear, they all have circuitry to convert alternating current to direct current before powering anything.
EXCEPT for the AC electric motor and the florescent light bulb -- two of the most common uses of power even today (and certainly before about 1960). In 1960 the refrigerator, the record player, the kitchen mixer and also various household pumps were powered by what was essentially a slightly improved version of Tesla's motor. The incandescent lights were also being run off his power too. Only really the radio needed a coil to convert to DC.
You joke about DC (Score:5, Informative)
But it was legitimately a problem back in the day. The reason was twofold:
1) There's no good way to generate DC using a mechanical system. So while something like a solar cell will generate you DC, a mechanical generator won't, at least not without some fiddling and then not as efficiently as AC. These days, not a big deal, we have good devices to convert from one to the other quite efficiently. However when the current wars were happening, DC generation wasn't as good as AC generation. You see it to this day: Cars use alternators (as in alternating current) to generate power, despite being DC devices. The alternator then has a rectifier bridge to turn it in to (pulsed) DC power, which the battery helps clean up.
2) There was no good way to convert DC voltage. AC is exceedingly easy to convert with simple technology: A transformer. You can step it up or down with some wraps of wire, and it is fairly efficient to boot. No such luck with DC. There just isn't a good way to step it up with the technology they had back then. As such you needed generators close to the home. You couldn't run massive voltages, far too dangerous (and as a practical matter difficult to generate directly) and you couldn't go for long runs because of impedance loss. These days thyristors can do the trick nicely but they are 1950s tech, and the ones that can do HVDC are more recent.
Were we to rebuild the grid these days, DC might well make sense (though it does have some other issues that need to be considered). However during the current wars, Tesla really did have it right. The technology was there to make AC work well, not DC.
Edison really was fighting for DC because of his invested infrastructure, not because it was a superior technology at the time.
Re:false equivalency (Score:2, Informative)
Yes, and Nikola Tesla was simply wrong in promoting alternating current for about any use. If you look at modern electrical or electronic gear, they all have circuitry to convert alternating current to direct current before powering anything.
Except for just about all uses of power till home electronic equipment was invented in the 80's. In 1960 just about everything in the home was powered directly by AC (as in incandescent and florescent lights) or by an AC motor very similar to the one invented by Tesla. Only the radio needed a transformer to use AC power. Even today probably 90% of your actual power usage is of direct AC power (air conditioning and lights). So I would say that it is wrong to say Tesla was wrong.
Re:It's not all true (Score:4, Informative)
Re:Tesla is revered as god here... (Score:2, Informative)
http://en.wikipedia.org/wiki/Command_%26_Conquer:_Red_Alert No need to imagine it, go play it (it's been released for free).
Re:It's not all true (Score:5, Informative)
While true, it's also misleading. The inverse square law isn't magic, it's follows naturally on from basic geometry. If you take a 2D beam with any angle of spread, then at distance 2n from the source, it will be twice as wide as at distance n. If the beam is in three dimensions, then the spread will be twice as wide in each dimension, so it will be covering four times the area. This applies just as much to flashlights as to lasers, but it's not nearly as important in the latter case as the former because going from a radius of, say, 1mm at one km to 2mm at 2km doesn't really make much difference to the brightness, while going from 10cm at 1m to 20cm at 2m does.
With things like phased array antenna, it's possible to get the beam spread quite low, with lasers you can get it very low. The problem is not the inverse square law, it's that at the kind of power and directionality you want for this kind of thing you end up with something that has no problem propagating the power efficiently to the destination and will happily burn a hole through anything that tries to prevent it from doing so.
Re:Depends on how you measure (Score:1, Informative)
Re:Edison 'sold' lightbulbs (Score:5, Informative)
Often overlooked fact re Edison (Score:5, Informative)
Re:You joke about DC (Score:5, Informative)
Gauteng runs on AC, Cahora Bassa generates AC - but the line between them is DC. It gets rectified at the dam site and then reconverted to AC when it gets to the local grid.
There's another reason for doing that: you can't just stick two AC lines from non-synchronized generators together and expect it to work. They will actually work against each other, and you get a huge mess. This is a problem when combining two power sources from different countries. What's usually done in this case is to do an internal AC/DC/AC conversion to synchronize them.
Re:false equivalency (Score:5, Informative)
For modern high-voltage transmission, capacitive losses matter even at 50/60Hz. ....
That's an overly broad statement. Capacitive reactive losses really matter a lot on submarine or buried cable. Not much of a factor in overhead HV transmission. Think of it like the classic parallel plate capacitor - since that's what we have, just our "plates" are curved away from each other (which reduces capacitance, but let us consider them as flat here). The area (over the length of the lines) is large, yes. But what kills that off so to speak, is a product of two things: a poor dielectric medium (air) and a large distance (many meters) between the "plates".
For "plates" 3cm wide with a length of 1km and a separation of 10m: about 27pF. In other words: 27pf/km.
Formula: (where's my dang MathML slashdot?) C = k * E * A / S where:
C is capacitance in Farads
k is relative permittivity of the dielectric. Equals 1 (for air)
E is permittivity of space, a constant 8.85E-12 F/m
A is area in meters squared
S is separation distance in meters
For that 1km model above the impedance at 60 Hz is 100Mohm. For a 220KV line that is a loss of about 480W/km. Such a line would be conveying power in the few hundreds megawatt range. Not much of a reactive loss there. Different on sub/buried: k is much larger, and S is much smaller (mm - cm distances).
Re:Irrefutable fact (Score:2, Informative)
Bruce Lee > Chuck Norris
Re:Depends on how you measure (Score:5, Informative)
he was NOT a patent troll, since he BUILT the stuff he patented.
I'd would agree that he was a patent asshole, though.
Re:You joke about DC (Score:2, Informative)
The reason is that DC only requires as single cable - which can be supported by quite a thin little pole (the ground itself can be the return line).
AC works just fine with ground return as well:
http://en.wikipedia.org/wiki/Single-wire_earth_return
The high voltage supply that runs down my street is a single cable, which then goes into transformers to bring it down to North American domestic voltages. Nothing special DC and single cables.
Re:Irrefutable fact (Score:4, Informative)
Re:Depends on how you measure (Score:2, Informative)
He was both. Edison was ruthless about using his patents to keep superior products from competitors off the market. Stock tickers were a particularly notorious example. He was loathed by Wall Street traders who nevertheless depended upon his company's stock tickers, because they were well aware that others had invented superior ones with more functionality that Edison went to court to keep off the market.
The main difference was that 140 years ago, you couldn't root and reflash your Edison stock ticker to Cyanogen to give it those capabilities anyway. If Edison kept competing products off the market, they were unavailable. Period. As long as Motorola doesn't start designing phones for Apple (with hardware-locked bootloaders, encrypted JTAG ports, and flash with mandatory encryption so it can't be unsoldered, reflashed, and soldered back in) before Google's purchase is finalized and Moto becomes non-evil, we can hold our noses, grudgingly buy iPhones, jailbreak them, and reflash them to Android to give Steve a big posthumous finger.
Re:Edison to Deforest ... ALMOST! (Score:5, Informative)
This is ignorant. Yes he bought QDOS, and yes he had people working for him to modify it. This doesn't take away the fact that he was heavily involved in building the BASIC that was loaded into PROM on my PC-1! For the first several years of the company Bill coded. He also was very astute at guiding the financial and business aspects of his company, and being at the right place at the right time multiple times. Don't forget that he pointed IBM at Digital Research FIRST, before he went and purchased QDOS. At the time - Microsoft was a language company. They specialized in creating language compilers. That is how IBM had Pascal, etc. available for the PC the first day it was introduced!
GAWD - you're making me defend Bill Gates - STOP THAT! (Now I've got to go and compile a linux kernel or something to make up for this!)
Re:Confusing political systems with economic ones. (Score:4, Informative)
Neither Sweden nor Finland are member states of the NATO, and both were frontier states in the Cold War. No one else paid for their defense.
So this argument is moot.
A fact that ignores more complicated equations of geopolitical power struggles. Finland and Sweden were allowed to remain neutral because it suited the powers to allow that. For that same reason Switzerland remained neutral in WWII: it would have been too inconvenient to attack when it could be counted on to remain faithfully neutral. Both countries had just enough defense to make them undesirable as a target while the Soviets faced NATO. Don't confuse that with not needing NATO. They relied on NATO's existence as much as any member state did.
Don't confuse being a secondary target with not needing collective defense. Which is also the point made about socialist medical care: it works fine, while someone else is willing to foot the bill for it. Europe should be paying lobbyists in Washington to keep the US well away from national health care and price controls on drugs. Once the US stops paying for the drugs, good luck maintaining your cheap supply.
Patent Orc (Score:5, Informative)
he was NOT a patent troll, since he BUILT the stuff he patented.
True but he was a different kind of patent "troll". For example with the light bulb once Swan had patented his design in the UK Edison submitted a almost direct copy for patenting in the US and then tried to sue Swan for patent infringement in the UK! The two eventually settled out of court with Swan running the UK side of things and Edison in the US. So by today's standards he was not a troll but he was certainly some sort of unpleasant creature living under the patent bridge - a patent orc perhaps since he liked to raid others patents and got away with it due to his wealth?
Re:You joke about DC (Score:4, Informative)
There's another reason for doing that: you can't just stick two AC lines from non-synchronized generators together and expect it to work. They will actually work against each other, and you get a huge mess. This is a problem when combining two power sources from different countries.
It doesn't have to be different countries. After the Fukushima disaster, the power problems in Japan were compounded because of purchases made more than a hundred years ago. In 1895, the first electrical generators were installed in Tokyo, purchased from AEG in Germany; a year later, Osaka installed generators purchased from General Electric. AEG's generators produced 50-Hz power, while GE's generators produced 60-Hz power. This dichotomy exists to this day, so that western Japan runs on 60-Hz power, while eastern Japan runs on 50-Hz power. There are four back-to-back HVDC convertors at the border between the two grids to convert between the two frequencies, but it didn't have anywhere near the capacity to shift more than a fraction of the load to the western grid after 11 nuclear generators (including the three at Fukushima) were shut down in response to the quake, taking 9.7GW off the eastern grid.
Oatmeal repsonds (Score:5, Informative)
Here's a great response to the forbes article, from the author of the article that the Forbes article is critiquing:
http://theoatmeal.com/blog/tesla_response [theoatmeal.com]