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The Last DC Power Grid Shut Down in NYC
cell-block-9 writes "Today the last section of the old Edison DC power grid will be shut down in Manhattan. 'The last snip of Con Ed's direct current system will take place at 10 East 40th Street, near the Mid-Manhattan Library. That building, like the thousands of other direct current users that have been transitioned over the last several years, now has a converter installed on the premises that can take alternating electricity from the Con Ed power grid and adapt it on premises.' I guess Tesla finally won the argument."
Or that he died broke and alone because people like Edison stole his ideas and robbed him blind. Tesla was a genius and could have done so much more for the world if only things weren't controlled by rich people with no vision further than how much money they can make, right away, off an idea. Tesla's failure is a perfect example of capitalism at work.
At what price learning? At what cost wisdom? The price is a man's peace of mind, and the cost is his life.
First of all, let me tell you that Tesla is one of my role models. He is one of the reasons I studied electrical engineering - with a passion. And AC, if you want, is the "winner" for all intents and purposes. The future really validated Tesla's AC system. There have been other folks that helped the adoption of the AC system, like Proteus, another role model for me.
Said all that however, high-voltage DC, a transport technology that starts to make sense nowadays, thanks to high-power solid-state switching elements, has many advantages over AC in terms of losses and cable utilization. You can transport more energy via DC than AC, across the same thickness cable. And you have practically no losses due to parasitic capacitances and inductances. The corona effect is much easier to control, too.
So, if I was forced at gunpoint to make a prediction for the electricity transportation in 150 years from now, I'd say hihg-voltage DC.
"The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
A few, but not very many. The main one is that many power uses require DC in the end, so AC has to be rectified and filtered before it's used -- and in doing so, some power is lost. When/where you're using a lot of power in a relatively restricted area, that can make a meaningful difference. Automobiles, for one obvious example, mostly use 12V DC systems (nominally 12V -- really around 14V). Aircraft, for another example, mostly run on 48V DC (IIRC). Some data centers have also gone to having a single big power supply, and then piping DC around to the individual computers. I haven't measured it personally, but they claim this can cut power usage by around 30% in some cases.
Another difference is that getting shocked by DC tends to be slightly less dangerous than the same shock from AC. A 110V DC shock to bare (unbroken) skin is is quite mild feeling, where most people in the US have found (sometime or other) than 110V AC is fairly uncomfortable, though usually not particularly dangerous (i.e. for every person who dies of electrocution, an unknown but certainly large number of others are shocked with no real consequence beyond surprise and discomfort).
The universe is a figment of its own imagination.
Actually DC current is more efficient than AC in transmitting power due to there being no reactive component of the power. The main problem with DC is that it cannot be transformed to higher voltages which save a lot of energy losses. There is actually a very long DC transmission line to California that uses DC power. They convert to AC at the end of the line. AC is also a much safer means for transmitting power. It is nearly impossible to extinquish a fault on a DC line because the voltage never reaches a zero point. Protection devices on AC lines rely upon the zero point to extinquish faults.
Kinda sad to me but it was in the way of progress. Lots and lots of buildings still use the old DC elevators here in New York City. Just yesterday I loaded in to Bayard's in downtown Manhattan into a 4x4 foot elevator that I swear Otis himself must have installed. I love how you have to hold the lever to go up and down and manually align the elevator to the floor. The elevator lights are powered by the DC current as well. At Pratt Institute they used to have those old DC elevators that were powered by an ancient motor generator set that was dated back to the 30's. Hell up until 1999 the MTA still had an old DC substation that had Rotary converters for the subway. ConEd also kept the 25 cycle plants running to feed those substations until the early 90's.
If you want a feel of old DC equipment from the days when if you wanted power you had to make your own, head down to Pratt Institute (located in Brooklyn on Willoughby ave. and Hall st.). They still have 3 steam driven reciprocating piston dynamos built by Ames Iron Works. They work but are only for show. And to top it off they also have a steam turbine dynamo all of which is hooked to a large open marble panel board with knife switches, carbon arc circuit breakers and blade fuses. The panel is still live on the AC side. The Motor generator I mentioned is still there. You can go down to the Pratt engine room and get a tour from Conrad Milster, the Chief engineer who keeps the place running. The large 1930's brick steam boiler still heats the campus and the surrounding neighborhood. The site is an IEEE land mark and walking down there is like going back in time, a real treat.
people are fond of pointing out democracy's many failures too
The failures of democracy aren't democracy itself, but rather of the fact that our implementation of democracy is poor in that it doesn't actually give people the representation in government that they should have. Its too easy to get re-elected, its too hard to break into politics without vast amounts of cash and/or support from existing politicians, its too hard to remove someone who is doing a shitty job, its not nearly transparent enough, the voters don't have more than a token say in most issues as elections are only 'big issue items', and too infrequent to give voters real voices in more mundane items, like patent reform, whether the RIAA should be allowed to sue children, etc. And its too hard to vote. (seriously, the cost and organization to run an election or referendum are an obstacle to effective democracy). First past the post elections wipe prevent minority views from having any voice at all.
There is nothing wrong with democracy. We just don't have a good implementation of one.
Capitalism on the other hand has many REAL flaws, even if implemented perfectly. And a hybrid of capitalism and something else is the only way of fixing it, short of a completely new paradigm like the star-trek-economy where scarcity of resources is pretty much a non-issue.
so please, criticize capitalism. but unless you can enunciate a superior alternative, your criticism means absolutely nothing
Bullshit. The first step in fixing a problem is to identify what the problem is.
But you want solutions to capitalism? Sure, close the borders with any other country that doesn't implement capitalism the same way we do, so that we can compete under a fair system. A great deal of capitalisms problems stem from the comparative advantages of -exploiting- foreign economies that don't have the level of protection of human rights, wages, environment, etc. Or alternatively to closing the borders, treat foreign assets and employees as local ones -- and ensure wages and working conditions and environmental practices are compliant with local standards regardless of where the plant is. Its one thing for there to be a competitive advantage by refining your oil closer to the source, or taking advantage of high unemployment and locating a call centre in its epicenter -- but its something else entirely to exploit a 2nd or 3rd world country to get labour at a fraction of its real value to you.
Second, re-design corporations - make directors accountable personally, make ceos accountable personally.
Third, re-design the stock market so that its focussed on serving INVESTORS not TRADERS. If corporations were interested in satisfying INVESTORS they would take a longer view, but right now all that matters is tomorrows share price and this quarters sales. Only traders care about that.
Third, institute separation of commerce and state. Business should have NO ability to affect or impact on government at all. The biggest problem of capitalism is that its a corrupting force on democracy. Separate them.
I could go on...
I think the most beautiful piece of old AC to DC conversion technology was the mercury arc rectifier...apparently these devices were still used on some branches of the NYC subway until late in the 20th century. A video of one in operation can be seen at http://www.youtube.com/watch?v=Rt-a8fxgtno
A center-tapped transformer was connected to two anodes to form a full-wave rectifier(some had more anodes and were used for 3 phase power), and a pool of liquid mercury was used as the cathode material which would form an arc only if the anode was positive. A keep-alive electrode kept the interior full of vaporized mercury to facilitate the discharge. I'd sure like to have my own. Unfortunately an average sized mercury arc rectifier contains around 2 pounds of liquid mercury, so if it ever broke, my neighborhood would have to be decontaminated, my home razed to the ground, and the rubble buried in a concrete encasement.