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Banned on April 7, 2007 Registered Member #277
Joined: Fri Mar 03 2006, 10:15AM
Location: Florida
Posts: 157
Update... pic attached of a small dc motor powered by HV ions and the triboelectric effect and other ambient energy collected from the air by my hv collectors. If you look closely, you can kinda see the blades spinning (I gotta buy a new video cam). Also, slightly older news, but interesting none-the-less to me, are 8 jumbo LEDS powered by ions harvested from the air. I could show it driving a fuel cell producing hydrogren, but that would be nearly useless in a still pic. Lots of work left to do in order to increase efficiencies to where I'd like them to be, but little by little progress is being made, plus it keeps me busy and off the streets. This is the reason I originally joined 4hv.org to see if I could learn from people smarter than I concerning HV to LV conversions. CM
Registered Member #63
Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425
A note for you CM -- if you're ever hunting for HV diodes (e.g. for a bridge rectifier for your collector), I will recommend to you BY8418. They are 18kV 5mA diodes. They do need epoxy encapsulation (because they're designed to be used in potted equipment like flyback transformers.
They're also good for high frequencies past 100kHz or so.
Banned on April 7, 2007 Registered Member #277
Joined: Fri Mar 03 2006, 10:15AM
Location: Florida
Posts: 157
Blackplasma, thanks for the info. Eric, HV to LV conversion efficiency is low, lots of energy still left on the HV side of the equation. I'm using a spark gap as the switch in the below buck converter (aka Snubber circuit). I think considerable energy is being lost in the spark. I've got some alternative ideas to a spark gap and continue working to improve it, little by little, baby steps. Whatever switch I use needs to be able to handle up to 50-70kV at up to 300 amps (for a few nanoseconds) without frying. CM
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
You might want to try replacing the diode with the BY8418 type of high voltage diode that BP recommended. If my understanding is right, a diode with a high voltage rating would make the circuit more efficient.
Banned on April 7, 2007 Registered Member #277
Joined: Fri Mar 03 2006, 10:15AM
Location: Florida
Posts: 157
Tried that sometime ago, oddly, it decreased the power output. So far, I've tested over 60 different makes/brands of diodes, from basic to exotic diodes as well as spoken with many applications engineers at diode companies. A large portion of this project turns out, unfortunately, to be counter-intuitive. So I keep daily logs, schematics, results in my notebooks (6 so far) and occassional pictures and have documented some very curious results that occur during specific environmental conditions which I'd love to share with the intelligent people here for feedback, but honestly, I feel I'd just get shot down again by management, or the thread closed, or invoke the rarely used double-blind test ploy to delete my posts again. Anyway, back to the topic at hand, my present focus is on reducing loses in the on/off switching of the circuit by searching/testing a suitable on/off replacement for the spark gap that can handle the V/amps. Based on past improvements, I believe that if a respectable portion of the on/off switching loses can be reduced (currently the spark gap), the final output will increase by several orders of magnitude. CM
Registered Member #69
Joined: Thu Feb 09 2006, 07:42AM
Location:
Posts: 116
Nobody is going to shoot down any data you present. Speaking of data, have you recorded voltages/currents during a spark on both sides of the circuit using a scope? This would tell you all you needed to know about was happening and where your losses were.
Also, have you recorded the voltage on your collector/capacitor side during the charge up period? Open circuit voltage? Inquiring minds want details.
Registered Member #618
Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628
I'd say if your worried about losses due to the spark gap, I'd think switching the gap for a neon or flash tube, they might still produce a spark of sorts but at less energy consumption that a spark would produce, and still allow the energy to pass to the LV circuit and be used. But hey if thats a bad idea, my bad I've only been taught low voltage and only been out of college for 1 year, and as every job interview I've been to "You DON't have enough, experience!" sorry got off topic.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Hmm, if using a higher voltage diode decreases the output, that kind of suggests you are dealing with RF oscillations caused by the spark gap, instead of plain high voltage pulses. Did you try any of the following:
Move the inductor to before the diode ie, so it's in series with the antenna. Put a second diode where the inductor used to be. This might lower the current and frequency of the oscillations, which would reduce radiation and conduction losses and maybe even make them easier to rectify. If this is correct, the total energy harvested ought to increase.
Further along this line of thought: Ground the bottom of the inductor and connect a single rectifier diode to a tap on it. Adjust the tap for maximum energy.
Another possibility: Wind a secondary winding with fewer turns of thicker wire on the inductor near the grounded end, and connect this to your storage capacitor with a bridge of four fast diodes. Experiment with number of turns and coupling.
Improve your ground connection (more deeper ground rods in damper earth, or even RF counterpoise wires)
Banned on April 7, 2007 Registered Member #277
Joined: Fri Mar 03 2006, 10:15AM
Location: Florida
Posts: 157
Tried all except the 2ndary winding on the inductor idea, including replacing the spark gap with floresent, neons and many other type 'gas' filled spark gaps. For some time I've suspected that my grounding system is inadequate, currently a total of 60 feet of 4 inch copper pipe in 20 foot sections, all three 20 foot sections are veritically buried in the ground connected to each other by ground wire. The vertical copper pipes might be a good DC ground, but not necessarrily a good RF ground (that is my pure speculation at this point). Recently, I had the back end of a large dump truck buried near my RV (aka lab) and I plan to measure if a larger mass - horizontial style ground makes any difference whatsoever. CM
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