harnessing lightning, or not
in [Design]
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From: John Larkin on 12 Jun 2010 13:58 On Sat, 12 Jun 2010 10:36:20 -0700, Archimedes' Lever <OneBigLever(a)InfiniteSeries.Org> wrote: >On Sat, 12 Jun 2010 10:07:37 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Sat, 12 Jun 2010 08:45:11 -0700, BlindBaby >><BlindMelonChitlin(a)wellnevergetthatonethealbumcover.org> wrote: >> >>>On 12 Jun 2010 08:33:45 -0700, Winfield Hill >>><Winfield_member(a)newsguy.com> wrote: >>> >>>>John Larkin wrote... >>>>> >>>>> Winfield Hill wrote: >>>>> >>>>>> My Maxwell capacitors hard at work energy from harnessing lightning, >>>>>> see my post with photo, at the CR4 forum. >>>>>> http://cr4.globalspec.com/thread/55751/Lightning-Arrestor#comment579837 >>>>> >>>>> You rate 3 "good" answers out of 14. That site has very high >>>>> standards! >>>> >>>> Yes indeed! My lightning answer, complete with photo and >>>> calculations, is not yet a "good answer" because it didn't >>>> get enough votes. Hmm, it did get one vote, was that from >>>> you John? Thanks! >>>> >>>>> Why not use the lightning to heat water? The impedance match is >>>>> potentially better, and it's easy to store hot water. We could >>>>> throw a neighborhood hot-tub party after every strike, every >>>>> 40 years or so. >>>> >>>> Aren't there serious problems with developing a high electric >>>> field in water? I mean, above about 1V it wants to break apart >>>> into H2 and O. And what about the electrode double layers? >>>> >>>> I dunno, it'd need to be a tall 1MV / 100kA = 10-ohm resistor >>>> with water cooling, or something. But if rated at a puny 1MV, >>>> it wouldn't warm up much water, with only 1MJ of energy. Sigh. >>>> >>>>> We don't get lightning here. I kind of miss it. >>>> >>>> Yes. >>> >>> >>> If it can make it from way up there all the way down to way down here, >>>it can certainly make it across any dielectric inside any cap, so you >>>guys are poking holes in the insulator layers to beat the band, in your >>>caps.. >>> >>> A cap to store SOME lightning strike energy would be about a 300' x >>>300' (or more) insulator plate of Delrin or Teflon, or an even thinner >>>plate of GLASS. The storage plate would have to be completely >>>encapsulated. >>> >>> One ends up with a large, flat form factor Leyden jar. >> >>Do the math on that, please. >> >>John > > Lightning: Smallest bolts are like 6MV. They drop down from a mile in >the sky. They can surely make it across ANY two terminal device you >think you can come up with. Unless you are separating the nodes by over >a mile. > > My cap would flash over as well, but more would remain stored than in >any of the scenarios discussed here thus far. I doubt that. Show us some numbers. Like Win did. > > No math required. Hand waving. What you mean is that you can't do math. Which means you can't design electronics. John
From: Bert Hickman on 12 Jun 2010 13:56 Winfield Hill wrote: > John Larkin wrote... >> >> Winfield Hill wrote: >> >>> My Maxwell capacitors hard at work energy from harnessing lightning, >>> see my post with photo, at the CR4 forum. >>> http://cr4.globalspec.com/thread/55751/Lightning-Arrestor#comment579837 >> >> You rate 3 "good" answers out of 14. That site has very high >> standards! > > Yes indeed! My lightning answer, complete with photo and > calculations, is not yet a "good answer" because it didn't > get enough votes. Hmm, it did get one vote, was that from > you John? Thanks! > >> Why not use the lightning to heat water? The impedance match is >> potentially better, and it's easy to store hot water. We could >> throw a neighborhood hot-tub party after every strike, every >> 40 years or so. > > Aren't there serious problems with developing a high electric > field in water? I mean, above about 1V it wants to break apart > into H2 and O. And what about the electrode double layers? > > I dunno, it'd need to be a tall 1MV / 100kA = 10-ohm resistor > with water cooling, or something. But if rated at a puny 1MV, > it wouldn't warm up much water, with only 1MJ of energy. Sigh. > >> We don't get lightning here. I kind of miss it. > > Yes. > > Win, For short (a few usec or shorter) pulses, water is actually a very good dielectric. Because of its high permittivity (~80), water is often used as the dielectric material in high voltage, low impedance transmission lines and interim capacitive storage units used in high-energy pulsed power systems, such as Sandia's ZR machine. The shorter the pulse width, the greater the peak voltage that can be supported across a water gap. An empirical relationship was developed by J. C. Martin under a uniform E-field over a range of voltages, pulse times, and electrode area based upon his work at Sandia: F = k*(t^(-1/3))*(A^(-1/10)) where: F = the peak breakdown field (in MV/cm) t = duration of applied voltage (in microseconds) A = area (in square cm) k = 0.3 for water (positive streamers � the normal case) k = 0.6 for water (a special case where field enhancement is purposely adjusted to cause streamers to form preferentially from the negative electrode instead of the positive electrode) For example, positive streamer breakdown field (F) for a pair of 100 square-cm electrodes in water, stressed by a 1 microsecond pulse should withstand a field of ~189 kV/cm. If we used a 100 nsec pulse, this increases to ~408 kV/cm, and to ~879 kV/cm for a 10 nsec pulse. YMMV - media degassing (or outright pressurization) is essential to prevent premature breakdown. Considerably more detail can be found in "High Power Switching" by Ihor M. Vitkovitsky, ISBN-10 0442290675, �Introduction to High Power Pulse Technology� by S. T. Pai and Qi Zhang, ISBN-10 9810217145, and "High-Voltage Electrical Breakdown of Water" by M. Kristiansen and L Hatfield, ISBN-10 1934939005. Breakdown behavior changes with longer (>10 microsecond) pulses, since ionic conduction begins to alter the E-field distribution within the gap. Metallic salts are often intentionally added to water to create high power/high voltage aqueous dummy load and divider resistors for pulsed power work. The electrolyte and end terminal materials must be compatible for long-term stability. Some excellent on-line information sources include a 5 page report from R. E. Beverly III & Associates and a large (147 page) report from Sandia. http://www.reb3.com/pdf/r_appl.pdf http://www.ece.unm.edu/summa/notes/ESDN/ESDN%205.pdf Let me know when you want to begin using that cap to do some serious EM metal-forming/con shrinking... :^) Bert -- ******************************************************************** We specialize in UNIQUE items: coins shrunk by ultra-strong magnetic fields, Captured Lightning Lichtenberg figure sculptures, and scarce technical Books. Please visit us at http://www.capturedlightning.com ********************************************************************
From: Archimedes' Lever on 12 Jun 2010 14:20 On Sat, 12 Jun 2010 10:58:49 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >> My cap would flash over as well, but more would remain stored than in >>any of the scenarios discussed here thus far. > >I doubt that. Show us some numbers. Like Win did. If lightning comes down here from a half mile up, it can certainly span the distance between the nodes of any cap you can name, unless it gets made as I described, with its nodes parted by vast distances. Again, no friggin numbers needed. And I did mention numbers. 6MV and up. Duration doesn't matter. What matters is that the cap's insulative layer survives the charge event without a plate to plate breach. A huge, flat, encapsulated charge plate, placed flat against the Earth plate will charge up, and hold charge, even after some flash over. The closer the charge plate can be placed to the Earth plate, the higher the final charge will be, IF and AS LONG AS there is ZERO punch through on the insulator. Since glass is the best, a thin glass plane mated to the charge plate, and then encapsulated except for an in/out node is all that is needed. The other plate is tied to Earth. The math is the plate area, and the plate separation. The same math used for capacitance calculation the whole time. If we can get the plate closer without a breach, the capacitance of the assembly will grow. I am not sure, but I am unaware that Maxwell, RIFA or anyone else is making any 6MV caps, much less a 20MV one, which is what we would need to catch a 6 to 10 MV strike. So the goal must then be to KEEP whatever we can of a failed capture. That would be whatever remains in the cap AFTER the strike and flash over events pass. Ideally, we would need a top plate encapsulating the charge plate of about a 2 mile diameter with the node at the center, to actually "catch the whole bolt". Again, if it can jump down here from way up there, then we need a top plate at least as big as the gap is between down here and up there. Since we will never get a cap that big, my flash over scenario is all we are left with. That is, IF you want to actually capture the voltage levels of the lightning,as well as the energy sent. Anybody can take a strike on any cap and have it charge to its voltage. Show me a cap than can take any lightning hit, and actually be charged to the voltage that the strike was sent at. Now, does my football field sized cap sound better? A knowledgeable man would be able to weigh these principals and discuss them, without much mention of math to any great degree at all.
From: Archimedes' Lever on 12 Jun 2010 14:21 On Sat, 12 Jun 2010 10:58:49 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >Hand waving. What you mean is that you can't do math. Which means you >can't design electronics. > >John You are wrong again, John. And it is quite funny that this is the only 'hand' you have to wave. It is also quite telling, however, that you wave it without any real foundation whatsoever.
From: John Larkin on 12 Jun 2010 14:35
On Sat, 12 Jun 2010 11:20:05 -0700, Archimedes' Lever <OneBigLever(a)InfiniteSeries.Org> wrote: > > A knowledgeable man would be able to weigh these principals and discuss >them, without much mention of math to any great degree at all. Hilarious. Engineering is all about the math. John |