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Ask Greg Leyh of The Lightning Foundry What Charges Him Up?

samzenpus posted more than 2 years ago | from the prepare-the-lightning-cannon dept.

Science 88

Greg Leyh is an electrical engineer who has spent most of his career working around particle accelerators and high-voltage machinery. Recently Leyh has been working on The Lightning Foundry, a project to see if humans can replicate the voltage economy effect of lightning. With the help of a Kickstarter campaign and a pair of 10-story Tesla Coil towers he hopes to generate man-made lightning. Greg has agreed to take some time away from his lightning machines and answer your questions. Ask as many as you like but please confine your questions to one per post.

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Looks Like a Lofty Kickstarter Goal (5, Interesting)

eldavojohn (898314) | more than 2 years ago | (#38267824)

Your kickstarter page lists a goal of some $348,000 to do the full experiment as per your cost breakdown [lod.org] . You are now at $32,000 with five days to go meaning some of these components are not going to be affordable. Could you please explain what is being cut or if you're doing the experiment at all?

have you never used kickstarter before? (2)

poetmatt (793785) | more than 2 years ago | (#38269794)

if you don't get successful funding on kickstarter, you get zero dollars and nobody who offered to contribute gets money. Had you read the fucking information at kickstarter, you'd know this.

So I'm assuming funding must be coming from elsewhere.

Re:have you never used kickstarter before? (0)

Anonymous Coward | more than 2 years ago | (#38269964)

*nobody who offered to contribute actually gets the money they offered to contribute taken out of their accounts*
sorry, bad english.

kickstarter only "kicks in" when it's successfully funded.

Re:have you never used kickstarter before? (0)

Anonymous Coward | more than 2 years ago | (#38271964)

fucking information

Well, you told him. Do you always demean information like that or do you have a tiny dick and need to compensate for it by lording the single thing that you know better than someone else over them?

Re:have you never used kickstarter before? (0)

Anonymous Coward | more than 2 years ago | (#38304330)

Hi Eldavojohn!

Re:Looks Like a Lofty Kickstarter Goal (0)

Anonymous Coward | more than 2 years ago | (#38271778)

It's not lofty, for that matter, its not even necessary. The "voltage economy" (technically "current economy") is the result of constriction of the plasma channel lightning travels through - and the inherent negative resistance of plasma. Though in all honesty, if I had thought of it first, I'd pretend I didn't know to trick people out of funding to build the world's largest Tesla Coil too.

Re:Looks Like a Lofty Kickstarter Goal (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277472)

The 'voltage economy' mentioned above occurs during the stepped leader phase, which is very low current compared to the return stroke. High current arc discharges at the laboratory scale fair no differently than low current ones; the current only occurs after the initial breakdown phase, so it cannot be a factor. Seriously, if you think you have a valid answer for this, you should publish.

Re:Looks Like a Lofty Kickstarter Goal (0)

Anonymous Coward | more than 2 years ago | (#38283454)

Well let's just pretend it's not a factor for now - I want to see bigger Tesla coils as much as you do, but measuring plasma densities will give you the answer.

Re:Looks Like a Lofty Kickstarter Goal (2)

Greg Leyh (2525318) | more than 2 years ago | (#38276714)

Hi, If the KS campaign doesn’t reach the goal, then we’re simply back where we started. You don’t get a dime unless you reach your goal in the allotted time. You can be sure though that we'll keep working on the design, and looking for ways to score the materials. -Greg Leyh

Measurements and Devices? (1)

eldavojohn (898314) | more than 2 years ago | (#38267860)

What sensors are you employing to measure this lightning bolt? I don't know much about The Electrum Project or what sort of data it produced for lightning on demand so can you give us very technical details of the sensors in this experiment? Is this more a proof of concept or academic endeavor? Am I missing something on your balance sheet [lod.org] or from Electrum's site about sensors, result sets and data?

Re:Measurements and Devices? (1)

Greg Leyh (2525318) | more than 2 years ago | (#38276742)

Electrum was primarily a lightning sculpture. However, once it was operational we took the opportunity to climb into the electrode and measure the actual base currents of the arc, since the electrode easily accommodates a person while it’s at full power. I used a Fluke 2-channel battery powered oscilloscope, connected to two Pearson fast current transformers. One CT was around a metal 'fishing rod' that I would poke out of the electrode to attract arcs. Here’s some of the waveforms we captured: http://www.lod.org/Projects/electrum/techdata/waveforms.htm [lod.org] Note the appearance of unexpected high frequency bursts that appear on the crests of the wave in the last two images. They have about a 400nsec time constant. They occur only on the *negative* crest, in a time frame where the output voltage is essentially DC. I still don’t have a good explanation for these odd bursts. With the Lightning Foundry, we’ll be looking instead for relativistic runaway breakdown events in air. Specifically we’ll use wide spectrum radio receivers to look for narrow bipolar pulses, and gamma-ray detectors to survey for evidence of relativistic particles.

Re:Measurements and Devices? (1)

CnlPepper (140772) | more than 2 years ago | (#38279282)

The polarity observation could be consistent with the relative difficulty of producing -ve streamers compared to +ve streamers. +ve streamers are generally produced at a lower E-field than -ve. It is possible you are seeing this preferential breakdown behaviour in your current results.

Thomas Edison or Nikola Tesla? (0)

eldavojohn (898314) | more than 2 years ago | (#38267918)

Who would you rather meet for a day and why?

Re:Thomas Edison or Nikola Tesla? (0)

Anonymous Coward | more than 2 years ago | (#38268356)

Who would you rather meet for a day and why?

Silly question IMHO: Tesla obviously, the 'why' might be interesting though.

Re:Thomas Edison or Nikola Tesla? (1)

GameboyRMH (1153867) | more than 2 years ago | (#38268738)

Why? Edison was a great big asshole, Tesla wasn't. Easy choice. Mod me Informative.

Re:Thomas Edison or Nikola Tesla? (0)

Anonymous Coward | more than 2 years ago | (#38270260)

...Tesla wasn't

Unless you are overweight, or are not OCD about cleanliness, hygiene and dress, then your mileage might vary with him.

Re:Thomas Edison or Nikola Tesla? (1)

Greg Leyh (2525318) | more than 2 years ago | (#38276950)

Tesla, definitely. He’ll know a great place for dinner and tell better stories.

Re:Thomas Edison or Nikola Tesla? (0)

Anonymous Coward | more than 2 years ago | (#38278888)

Nick shows up dressed nicely.
Tom's been sleeping in his suit for six months in the alley behind the building.

jr

modern switching tech? (1)

vlm (69642) | more than 2 years ago | (#38267984)

Whats the high voltage high current switching scene like now a days? In ye olden days krytons and friends were thought to be cool, but expensive and export controlled. Now a days do you just import high voltage mosfets from China and call it good, or ...

Re:modern switching tech? (1)

Greg Leyh (2525318) | more than 2 years ago | (#38276766)

For this relatively slow, high power application, IGBTs are currently the best choice. Each of Lightning Foundry towers will use an array of 4500V IGBT transistor modules made by Mitsubishi. These are typically used to run electric trains or wind turbines. At $1500 a piece, they’re by far the largest line item in our budget.

Differences (1)

Zomalaja (1324199) | more than 2 years ago | (#38268004)

Aren't tesla coils continuous alternating current and Lightning an almost instantaneous pulse of direct current ? I'm wondering if those differences diminish the usefulness of this experiment.

Re:Differences (1)

vlm (69642) | more than 2 years ago | (#38268094)

You can send a single pulse into a tesla coil at resonant freq, err resonant period anyway, no problemo. It certainly reduces the heating problem.

Re:Differences (1)

CnlPepper (140772) | more than 2 years ago | (#38273008)

It also makes it do bugger all (I suspect that is what you were suggesting re "heat problem"). The whole point of running it resonant is to build up the voltage in multiple "stages". What you are suggesting would be like kicking once on a swing and leaving it at that. That'll be a boring swing!

Re:Differences (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277564)

Hopefully my response in 'Re:AC_DC' below will answer your question. -Greg Leyh

Great plan! (1)

Anonymous Coward | more than 2 years ago | (#38268018)

Great! So generating lightning bolts from gigantic tesla coils might be more efficient if they're ridiculously gigantic instead! What was the point of this again?

AC/DC (1, Interesting)

Anonymous Coward | more than 2 years ago | (#38268058)

A Quick question: How exactly does AC electrical arcs produced by a Tesla coil help us understand the naturally occurring DC lightning produced by clouds?
Are not the two vastly different?

Re:AC/DC (1)

Greg Leyh (2525318) | more than 2 years ago | (#38276886)

That's a great question, and a not so obvious one! Many members here on Slashdot have noted quite correctly that natural lightning is driven by largely DC potentials, where a Tesla Coil is an AC device. However, a lightning strike actually consists of a complex series of interesting events, many of which are only 10s of microseconds in length, such as stepped leaders: http://en.wikipedia.org/wiki/Lightning#Lightning_initiation [wikipedia.org] The expected formation time of a relativistic breakdown is also on the order of 10s of microseconds. Compare this to the 20% flat-top duration of the Lightning Foundry output voltage sine wave, which at 5200Hz is about 40 microseconds. Although not a perfect DC source, hopefully the 40usec 20% flat-top will be able to generate significant RRB precursors. If we do start to see precursors we’ll likely add capacitance to lower the frequency, which will extend the flat-top duration. I'd like to offer the 'Vomit Comet' as an analogous example. Even though gravity is a 'DC' effect, the sine-wave trajectory of the Vomit Comet can induce a zero-gravity environment for a suitably long time during the crest of the trajectory. For some, it's too long. If we do come across strong precursors or other compelling results at our lowest possible frequency then the next step might be to increase the coil size, or propose building a considerably more expensive DC machine. The Lightning Foundry will be orders of magnitude more cost effective than a DC machine at this voltage level, and be able to operate at a much higher repetition rate. In addition, there’s other interesting research that an AC machine like the Lightning Foundry can carry out such as explorations in wireless power, or some unique coupling experiments with the Schumann Cavity.

FCC and friends (5, Interesting)

vlm (69642) | more than 2 years ago | (#38268060)

Short format: Are you going for 47 C.F.R. 15 sub B class A or class B? Just kidding, sorta.

Long format: Whats your plans regarding radio interference? Like, are you making a whopping big faraday cage out of an abandoned condo building, or have a FCC exemption under some R+D rule, or ... I'm just picturing armies of angry radio listeners storming your building with pitchforks...

Re:FCC and friends (0)

Anonymous Coward | more than 2 years ago | (#38269578)

People still listen to the radio?

Re:FCC and friends (1)

vlm (69642) | more than 2 years ago | (#38279006)

Yeah its called "the cell phone" or "the smartphone" or whatever. Also wifi, wireless ISPs, satellite TV, etc.

Re:FCC and friends (2)

Greg Leyh (2525318) | more than 2 years ago | (#38276776)

The Lightning Foundry coils won’t be a significant source of radiated power since the operating frequency will be only 5200Hz. This wavelength [about 36 miles] is *very* long compared to the tower height, so the radiation efficiency is almost zero. In addition, since the towers operate 180deg out of phase, their electric fields will tend to cancel at a distance. While operating Electrum at full power, a person viewing a TV one block away was not able to discern whether the coil was on or not by watching the picture quality. Of greater concern is the potential acoustic noise. The Lightning Foundry arcs could easily produce over 100kilowatts of acoustic power. To deal with this and general safety concerns we plan to operate the Lightning Foundry in a remote, mountainous section of southern Nevada, about 10mi from Boulder Dam.

Re:FCC and friends (1)

vlm (69642) | more than 2 years ago | (#38279142)

My "couple kilowatt" buzz box arc welder is a couple orders of magnitude lower peak power, arc length is a couple orders of magnitude lower, operating freq is 60 hz two orders of magnitude lower, and I can knock out all radio communication for quite a distance with it... The point being that specs won't save you, design will save you, since something much smaller is much worse. So the specific electrical engineering design elements of how you make a lightning generator make ten or so orders of magnitude less interference than a small arc welder would be an interesting technical question.

Some of the answer I donno about... each end of my ham radio dipole antenna is 180 degrees out of phase from each other and I have a whopping effective radiated power at distance... I don't think the details work quite the way you're describing. From a DC perspective, that is an accurate description. RF doesn't work like that.

I know they say only one question per post, whatever. If you're "near the dam" maybe you'll be accepting tourists? I only live 2000 miles away, but like most EE types I'd throw a couple bucks in the office coffee fund to see the sights of your new facility... sounds cool to me.

Ash Eyebrows (2)

Anne_Nonymous (313852) | more than 2 years ago | (#38268130)

Have you ever been injured working with electricity?

Re:Ash Eyebrows (1)

Greg Leyh (2525318) | more than 2 years ago | (#38276928)

I lost about 30 seconds of memory once, after touching a 5kV focus anode inside a TV set. Since then I'm especially careful, and a big fan of 'engineered safety features' such as mechanical crowbars that drop when you open a barrier to gain access.

SIBNIIE & HVRC experiments (3, Informative)

GameboyRMH (1153867) | more than 2 years ago | (#38268160)

How does your experiment differ from the SIBNIIE and HVRC long-spark experiments? [capturedlightning.com] Did you investigate the possibility of using their equipment instead of building your own?

Re:SIBNIIE & HVRC experiments (0)

Anonymous Coward | more than 2 years ago | (#38268576)

The photo was used in the presentation video for Kickstarter.

Other than that, it uses a Marx Generator and Karl isn't so popular anymore - he wants to use Tesla coils invented by that cool vampire-guy in Sanctuary. :)

Re:SIBNIIE & HVRC experiments (2)

Greg Leyh (2525318) | more than 2 years ago | (#38276904)

The Lightning Foundry differs from SIBNIIE in that we’ll be focusing on relativistic breakdown effects, and how they might correlate with observations taken from natural lightning strikes. SIBNIIE and HVRC accomplished an amazing range of research. As I understand it, most of their research was directed towards developing Extremely High Voltage transmission lines for transporting the plentiful hydroelectric power from distant northern Siberia. I believe that SIBNIIE was the first facility to generate what is called a ‘superlong discharge’, which is shown in your link. I haven’t come across a solid explanation for superlong discharges, nor do I know if they’re related to relativistic breakdown effects. However the SIBNIIE Marx did generate more than enough voltage to produce relativistic electrons. I do think there's some very interesting physics going on there that's worth pursuing.

PIE IN THE SKY !! OR DON'T STOP BELIEVIN ?? (-1)

Anonymous Coward | more than 2 years ago | (#38268164)

Winter is here again oh Lord
Havent been home in a year or more
I hope she holds on a little longer
Sent a letter on a long summer day
Made of silver not of clay
Ooo Ive been runnin down this dusty road

Ooo the wheel in the sky keeps on turnin
I dont know where Ill be tomorrow
Wheel in the sky keeps on turnin

Ive been trying to make it home
Got to make it before too long
Ooo I cant take this very much longer no
Im stranded in the sleet and rain
Dont think Im ever gonna make it home again
The mornin sun is risin
Its kissing the day

Ooo the wheel in the sky keeps on turnin
I dont know where Ill be tomorrow
Wheel in the sky keeps on turnin
Whooa My my my my my - 4-2-morrow

Oh the wheel in the sky keeps on turnin
Ooo I dont know where Ill be tomorrow
Wheel in the sky keeps me yernin
Oh I dont know I dont know

Oh the wheel in the sky keeps on turnin
Ooo I dont know where Ill be tomorrow
Wheel in the sky keeps on turnin
Ooo I dont know I dont know I dont knowohoh
Wheel in the sky keeps on turnin
Dont know where Ill be tomorrow
Wheel in the sky keeps on turnin
Ohh the wheel in the sky keeps on turnin
Wheel in the sky keeps on turnin

Van De Graff (1)

avandesande (143899) | more than 2 years ago | (#38268174)

Have you considered a large Van De Graff generator using plastic beads and compressed air?

Re:Van De Graff (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277322)

Hi, take a look at my response in 'Re:AC_DC' above, and let me know if that answers your question. -Greg Leyh

I'm not sure I understand what this guy is trying (3, Interesting)

JohnVKaravitis (2342882) | more than 2 years ago | (#38268204)

John V. Karavitis I'm not sure what this guy is trying to accomplish. Is this some kind of experiment into understanding the nature of lightning (don't we already understand how lightning works???), or is he trying to harness the power of lightning for commercial purposes? And what about the link that he provides, that shows a lightning discharge off of what seems like a large transformer? I think that, if someone posts an article or starts a topic thread here, we should at least be given the courtesy of an explanation. Thank you. John Karavitis

Re:I'm not sure I understand what this guy is tryi (0)

Anonymous Coward | more than 2 years ago | (#38268462)

I think there's an underlying Red Alert 2 motivation here.

Re:I'm not sure I understand what this guy is tryi (0)

Anonymous Coward | more than 2 years ago | (#38268614)

to see if humans can replicate the voltage economy effect of lightning

Inspired by Hollywood, he's trying to harvest 1.21 gigawatts of bioelectric power per human.

Who Are You? (0)

Anonymous Coward | more than 2 years ago | (#38268912)

Anonymous Coward Wait who's asking this question? Anonymous Coward

Re:I'm not sure I understand what this guy is tryi (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277008)

Hi John, The lightning initiation process still confounds experts in the field, which is understandable since the unpredictable nature and high altitude of lightning strikes effectively prohibit any close approach with scientific instruments. Several recent papers [Gurevich, Zybin, Dwyer] propose that ‘relativistic runaway breakdown’ effects might provide lightning with its amazing abilities. One conceivable way to study the lightning initiation process is to try and artificially trigger it. I'm proposing that it’s now arguably practical to build a machine large enough to recreate the conditions that theory predicts will trigger a relativistic runaway breakdown in air, on demand, and in a well-instrumented environment. More info on the project can be viewed here: http://www.lod.org/Projects/LightningFoundry/LightningFoundry.html [lod.org] Let me know if you'd like any more info. -Greg Leyh

Future experiments (1)

atherophage (2481624) | more than 2 years ago | (#38268206)

Will you be exploring anything along the lines of the Hutchison effects (http://www.rexresearch.com/hutchisn/hutchisn.htm) - and other other odd phenomena? Or are you just sticking to lightning?

Re:Future experiments (1)

nomel (244635) | more than 2 years ago | (#38268930)

It would be great if anyone could reproduce the Hutchison effects. :-|

Re:Future experiments (0)

Anonymous Coward | more than 2 years ago | (#38269026)

We'll be sticking to reality this time around, yes.

Re:Future experiments (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277114)

Hi, We'll be concentrating on lightning-related research, particularly effects that might explain the lightning initiation process. If we come across anomalous or unexpected effects we'll certainly explore those as well, particularly if they seem to pose a credible hazard to the machine or personnel. The possibility of running into unexpected behavior is very high when you build a machine that operates in a new part of parameter space. Most unexpected behavior turns out to be headaches; however a small percentage of these become discoveries. When we brought up the 1:12 scale Lightning Foundry prototypes for the first time, they behaved very erratically when adjusting the relative phase. As it turned out, the two coils had an unexpectedly strong ability to wirelessly couple power to each other, which wreaked havoc with the way we were controlling them. This headache eventually turned into a bit of fun though, since we were able to optimize their wireless capabilities enough to actually power a small manned vehicle, shown here: http://www.youtube.com/watch?v=CULdwXKKfDQ [youtube.com] I can only guess at some of the anomalies we'll run into when trying to ramp up the Lightning Foundry, but I'm certain the process will not be anomaly-free. -Greg Leyh

tl;dr - wtf? (1)

Thud457 (234763) | more than 2 years ago | (#38268278)

What do you mean by "Voltage Economy Effect of Lightning"?!!

Benefits? (1)

des_irl (1708908) | more than 2 years ago | (#38268424)

Could you explain a bit more about the possible benefits that mankind could gain from these experiments? Just for us lay-persons who don't really understand high energy physics and its associated terminolgy!

Re:Benefits? (2)

vlm (69642) | more than 2 years ago | (#38268730)

Traditionally giant lightning generators are used to develop lightning protection. For power companies, radio companies, telcos, aircraft, etc.

1) Design and build a model or life size machine that you think will survive a lightning bolt

2) Zap the heck out of it with artificial lightning

3) Did blow up? If so, analyze how it failed and go back to step 1

4) Did not blow up? Profit !!!!

The hilarious part is watching IT guys, who never get credit for their work when IT stuff doesn't blow up, trash talk the work of lightning protection guys, who also never get credit for their work when stuff doesn't blow up. "Stuff still blows up sometimes anyway" "Its just a wasted expense" "Lightning never hits the same place twice / you never catch the same virus twice" blah blah blah. The ham radio guys are just as bad, ten thousand nearby strikes and no effect on system performance, one strike finally takes it out and "all that stuff is worthless no point even installing it, stuff just blows up anyway". Idiots.

not saying it's the propper attitude.. (1)

Thud457 (234763) | more than 2 years ago | (#38268886)

The hilarious part is watching IT guys, who never get credit for their work when IT stuff doesn't blow up, trash talk the work of lightning protection guys, who also never get credit for their work when stuff doesn't blow up. "Stuff still blows up sometimes anyway" "Its just a wasted expense" "Lightning never hits the same place twice / you never catch the same virus twice" blah blah blah. The ham radio guys are just as bad, ten thousand nearby strikes and no effect on system performance, one strike finally takes it out and "all that stuff is worthless no point even installing it, stuff just blows up anyway". Idiots.

It's no "unscheduled downtime", it's a "upgrade opportunity".

Re:not saying it's the propper attitude.. (1)

GameboyRMH (1153867) | more than 2 years ago | (#38269084)

True, for some businesses it's the ONLY upgrade opportunity.

I wish I was kidding. The smallish company my dad works at has this sorry old Xeon server that absolutely CRAWLS. Takes 10 minutes to shut down, not kidding. The guy who runs the place is too much of a horrible cheap bastard to upgrade it.

Re:Benefits? (1)

des_irl (1708908) | more than 2 years ago | (#38270130)

Traditionally giant lightning generators are used to develop lightning protection.

Is that what this project is aiming for, because it seems strange that a person would have to use a crowd-funding model to fund research into a health and safety issue, that one would assume the likes of G.E. or Philips or some other multi-national would be able to do much more comprehensibly?

Re:Benefits? (1)

vlm (69642) | more than 2 years ago | (#38273276)

Is that what this project is aiming for, because it seems strange that a person would have to use a crowd-funding model to fund research into a health and safety issue, that one would assume the likes of G.E. or Philips or some other multi-national would be able to do much more comprehensibly?

I donno, but I know these facilities are expensive, and imagine where electronics would be if only G.E. could afford to own a soldering iron... or a C compiler...

Re:Benefits? (1)

CnlPepper (140772) | more than 2 years ago | (#38278530)

I'm a senior scientist in the lightning testing facility of Cobham Plc (which use to be known as Culham Lightning). We predominantly perform aerospace testing for the major european aircraft manufacturers. The aerospace lightning standards, such as ED-84, could not be practically achieved using a tesla coil arrangement. The current/voltage levels and waveforms shapes are very specific to simulate the effects of a one in a thousand (typically positive) natural lightning strike. These waveforms are easiest to achieve using large LCR circuits turned to provide the correct waveform shape from the load (e.g ED-84 Waveform A 200kA double exponential 6.4us rise/69us fall to half height). As they are inherently AC devices, Tesla coils devices can not provide the correct waveform shapes to simulate a natural lightning discharge. They are also unsuitable for attachment testing or dielectric breakdown tests are they do not maintain a continuous E-field as seen in nature and simulated in the test standards.

Re:Benefits? (1)

CnlPepper (140772) | more than 2 years ago | (#38278544)

*turned = tuned

Re:Benefits? (1)

vlm (69642) | more than 2 years ago | (#38279362)

True and your facilities work is valuable, but, maybe the first part of a development cycle could be done cheaply with a "zap it and sniff for smoke" methodology at a small facility.

If your device can't survive a small scale tesla coil, no point hooking it up to a calibrated high power high expense facility like yours.

For example, several decades ago, I pulled cable for RS-232 cables for a specific model of VAX, which was famous (at least at our facility) for blowing out its rs232 line receivers if you touched the contacts. Not intense static zap, not nearby lightning strike, not direct lightning strike like you can simulate, but just casual contact, even in humid summer months while wearing cotton etc. There is space for a lot of R+D facilities and work between where that product was, and where your testing facility is; evidence of commercial lack of surge protection shows both are needed.

Re:Benefits? (1)

CnlPepper (140772) | more than 2 years ago | (#38280336)

Generally, you will find that the low-level surge testing is done in-house during development, especially by the larger electronics companies. This would be the wack it, smell it test (or more precisely - measure to see if any inboard transients occur that will damage stuff you want kept alive). We cater for the higher threat level requirements where the cost of the test equipment starts to become prohibitive and the test experience is of significant value (we advise on mitigation). Even for this aspect of lightning testing Tesla coils are ill-suited. Contact ESD, surge and coupled transients all have well defined standards (all derived from experimental measurements of typical threats) which a Tesla would not be able to correctly produce.

Re:Benefits? (1)

CnlPepper (140772) | more than 2 years ago | (#38280478)

One thing you have to bare in mind is a lot of companies are utterly allergic to spending more money on something than they have to - they want to know they are passing the standard at minimal cost, rather than risking spending money on something that may be unnecessary - one reason all the standards have a good margin of safety. As a tesla could not meet the standard, it would not realistically be considered. A cheap LCR circuit, a charge pump and a solid state switch would cost a similar amount and do exactly what they want.

Re:Benefits? (0)

Anonymous Coward | more than 2 years ago | (#38276698)

How about:

1. Transmission of power to anywhere in the world with losses of 1-5% WITHOUT having to go to the trouble of building or maintaining any power lines
2. You would be able to retro-fit practically any power station to do this for half a million dollars or less
3. Many devices wouldn't even need electrical wiring to be powered, just connection or not to a small, properly tuned coil.
4. Telsa's backers dropped out before he could fully demonstrate because they couldn't see how an individual could be charged for their power usage. These days you'd do it by charging a levy the same way your rates are charged, and for the larger power requirements (businesses etc) the receiving coil itself would be metered, just the way your houshold meter box works.

You'd be astonished at how much of your power bill goes to the maintenance and construction of transmission infrastructure and how much power is wasted by shoving it down cables.

AM radio would be finished though...

DC? (2)

Baldrson (78598) | more than 2 years ago | (#38268866)

Disclaimer: I'm a rank amateur, so be forewarned: When I was working with Paul Koloc on his erstwhile Plasmak(tm) lightning machine (when I still thought his photographs were real), I came up with a conceptually simple circuit that Paul seemed to think was (conceptually) superior to his simple (DC) capacitor discharge -- except that it was impractical given his mercury switch controls. As usual, you have to have a honking power supply charging a honking capacitor bank with a honking inductor coil ready to roll, but the trick is that at the point in the phase where the capacitor bank has been fully discharged into the inductor, you switch out the capacitor bank and replace it with the spark gap. This, purely DC system seems to better model actual lightning than AC systems doesn't it?

Re:DC? (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277668)

Hi, hopefully my response in 'Re:AC_DC' above will answer your question. -Greg Leyh

Let me rephrase the question (1)

Baldrson (78598) | more than 2 years ago | (#38280888)

Wouldn't this simple circuit be more economical?

For instance, if you take a few BMOD0063 P125 B04/B08 [maxwell.com] s each rated at 63F, 125V and maximum discharge current of 1,800A (energy capacity of (0.5 * [63 * farad]) * (125 * [volt^2]) ? joule = 3937.5 J) and discharged it into a 2000uH air core inductor ((0.5 * [2000 * {micro*henry}]) * ([1800 * ampere]^2) ? joule = 3240 J) might you not get the equivalent of a small car crash discharged at millions of volts by timing the switchout of the capacitor bank correctly?

Tesla coils produce AC. (1)

fuzzygerbil (1296955) | more than 2 years ago | (#38268934)

Small Tesla coils are typically run in pulsed mod, with duty cycles on the order of 0.1%. If you wish to run them continuously you need a 100Kw supply for even a small 5-10 foot coil, water cooled electronics, primary coil, and you will need induction heater grade capacitors. How do you plan on getting useful data from high frequency AC, and for that matter, high frequency AC which by nature is a decaying pulse stream on the order of .1-1% duty cycle?

10 what? (1)

Hognoxious (631665) | more than 2 years ago | (#38268948)

"10-story" says nothing. Are they tall stories or short stories?

Liability? (1)

wsanders (114993) | more than 2 years ago | (#38269982)

How are you going to deal with half the population living within a 10 mile range suing you for blowing out their home electronics, and when every ham radio operator within a 1000 mile radius complains to the FCC about you ruining their radio reception?

Re:Liability? (1)

TheCarp (96830) | more than 2 years ago | (#38271276)

Actually, not sure if the FCC can do much there. I remember looking into this when I was coiling and the advice that I always got was that the FCC bans jamming, but... radio equipment is not specifically protected from interference from the operation of other equipment. So the basic rule was that a tesla coil was "probably ok" but modulating the frequency to transmit radio signals, is certainly disallowed.

Not sure how this would apply to a zeusaphone, which is definitely modulated, and I hear can be picked up on an AM radio. Then again, since the purpose is to produce sound via the expansion of air around the discharge, well.... not sure, might get away on the technicality, but I would definitely consult a real lawyer on anything so big that your neighbors can tell its you and your damned coil.

Re:Liability? (1)

TheCarp (96830) | more than 2 years ago | (#38271686)

Actually.... I want to expand on your liability question....and maybe scare some socks off....

So, about 15 years ago, when I built my coil, I got to know another local coiler (I still drool over the pole transformer in his basement). At that time, he told me of an incident that he alleged happened to a friend of his. Basically, he was down in his basement running his coil, when someone upstairs smelled smoke. I don't remember much more to the middle of the story but, the ending was a bit scary....

A sweater in a closet had been on a metal hanger, which had acted as an antena and "picked up" his "signal" in he basement.... causing it to draw power and heat up, causing the sweater to smoulder.

Now, is it true? I don't know... maybe you know more? However, if thats possible with a small (compared to your proposed one anyway, this was probably a good size coil for home use), is there cause to worry about this?

Re:Liability? (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277036)

In 'Re:FCC and friends' above, I provided a rationale for why the radiated power will be very low. Let me know if you have questions beyond that.

Ok admit it.... (1)

TheCarp (96830) | more than 2 years ago | (#38271178)

You are just looking to build the world's largest zeusaphone. I can't blame you of course, but come on, its true isn't it? If not.... you have at least considered it? Maybe play some some megazuesaphone hero?

Re:Ok admit it.... (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277150)

Unfortunately I doubt the Lightning Foundry would be able to approach the magnificence of the Sousaphone.

Sorcerer's Apprentice? (0)

Anonymous Coward | more than 2 years ago | (#38271936)

Can you make your Tesla Coil's play music like in the movie The Sorcerer's Apprentice?! (come on... that's a good question!)

Re:Sorcerer's Apprentice? (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277640)

I don't think that I could do that.

Why? (0)

Anonymous Coward | more than 2 years ago | (#38272004)

You're just trying to create a very very long discharge? Why? Even on your own website talking about your last project, you don't provide any reasons, or any insights that were gained, you just mention how cool it looked/sounded.

Power Supply? (0)

Anonymous Coward | more than 2 years ago | (#38272498)

So, relatively simple question. What are you using for a power supply? Specifications? How long does it take to charge the system?

 

Re:Power Supply? (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277402)

Each tower will require up to 1.8 megawatts of AC prime power. The most economical AC power choice would be the local power grid. However, if the Lightning Foundry is required to operate in a remote area or if the local power authority cannot handle megawatt transient loading, then there are two options for generating the AC prime power: A) An gas turbine-alternator set or B) A stand-alone diesel generator. Option A is preferred over B, since a turbine set is considerably more compact and is easier to transport. If we’re not able to score an affordable turbine set or secure a robust connection to the power grid, then leasing a 2MW Diesel generator set is the remaining option.

So what? (0)

Anonymous Coward | more than 2 years ago | (#38275674)

What's the point of this? In other words, why is this worth doing? Is it really cool? Does it do something useful? I have to admit that lightning is kind of boring to me so creating artificial lightning sounds like a sorefest. I'm an EE btw.

No one has thought to ask this?

Re:So what? (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277302)

Certainly, most people will find this boring. Especially with all of the amazing diversions and entertainment available today.

Your Google Interview (0)

Anonymous Coward | more than 2 years ago | (#38276316)

Greg, are you allowed to tell them about the time Google interviewed you? Do include a link to the video....

Ralf

Re:Your Google Interview (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277382)

Hi Ralf, That interview was interesting [got to visit the amazing Google campus] but unfortunately it was completely unrelated to the Lightning Foundry. It involved something considerably more practical than pure research. I'm pretty sure there wasn't a video.

I thought "voltage economy" was understood. (1)

Ungrounded Lightning (62228) | more than 2 years ago | (#38276560)

Your web site seems to describe the goal of the project as understanding how lightning propagates as it forms and how it initiates at a far lower voltage gradient than one would expect from the ionization requirements of air, or (equivalently) jumps gaps far longer than would be expected from the voltage.

I was under the impression that this, along with the jagged nature of the bolt, was already understood. And that it went something like this:

  - A large enough charge accumulates, producing a strong field in the direction of a suitable opposing charge. But before the charge becomes large enough to ionize the air and jump the gap:
  - A charged particle (typically a primary or secondary cosmic ray) passing through or very near the collection of charge, produces an ionization trail with a component along the voltage gradient.
  - Some of the charge rushes to and along the path. This increases (and maintains) the ionization, redistributes the charge in a way that shortens the remaining gap, both increasing and focusing the field, and increses the size of the target for another ionizing particle.
  - If another particle comes by before the ionization decays, the process repeats, with charge moving along the new path in the general direction of the opposing charge.
  - Repeat until the remaining gap to a conductor, opposing charge accumulation, or similar path of opposite charge coming the other way, is short enough to be ionized by the now very concentrated field.

This explains, not just how an arc can form at far lower voltage gradient than exped, but also the jagged nature of the path (it follows random ionization trails going roughtly the right way), and the occasional forking (when a particle trail joins the extending arc somewhat back from the tip).

Please comment on whether this relates to your work. (I.e. Is this the explanation you're trying to find, confirm-or-falsify, or fill in details on? Are you looking for something else? Something additional?)

Re:I thought "voltage economy" was understood. (1)

Greg Leyh (2525318) | more than 2 years ago | (#38277234)

One problem with cosmic-ray induced breakdown concept is that the flux of cosmic-rays required to sustain a breakdown is much greater than the amount which naturally occurs at thunderstorm altitudes. J.R. Dwyer has proposed a very novel 'positive feedback' mechanism that solves this problem using *positrons* in his paper 'A fundamental limit on electric fields in air' which can be viewed here: http://bit.ly/t0XZ6M [bit.ly] The Lightning Foundry should be able to explore a portion of the parameter space in Figure 2, and a good part of the 'Semi-stable' regime in Figure 3.

Re:I thought "voltage economy" was understood. (1)

Ungrounded Lightning (62228) | more than 2 years ago | (#38288468)

Cool. Thanks.

Seriously... (0)

Anonymous Coward | more than 2 years ago | (#38276654)

Your website says: "The prototype twin coils often surprise us with wonderfully unexpected behavior, including a strong tendency to couple power wirelessly over large distances."

Surely this is not unexpected behaviour. This is Tesla coils 101!

The reason that lightning has the ability to produce discharges significantly greater than their actual electrical output would suggest is due to the low frequency standing waves present in the atmosphere. It was in fact the interaction of storm derived lightning and these standing waves which enabled Tesla to calculate the correct voltage and frequency required to use the earth and ionosphere as two plates of a capacitor for the "transmission" of wireless power. That was the key to tuning the transmission so that energy loss was only 1-5% as opposed to the insane amount of loss your present coil configuration has according to your paper.

Might also be worth looking into Schumann resonance as this phenomenon is now called. Some NASA people recently put out a paper which suggested to me that they were surprised that the effects of Schumann resonance could be detected beyond the atmosphere. Given the resonant frequency of the waves this should have been obvious. Does nobody actually think for themselves anymore?

Tesla was no magician. He was just a good engineer doing things that had never been done before. Keep at it!

Volts (1)

Nefarious Wheel (628136) | more than 2 years ago | (#38278586)

Twinkle, twinkle little volt
So far from your lightning bolt
To your anode in the sky
We will watch your sparkles fly

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