컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-09-94 12:57 From: Terry Smith To: Richard Quick Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> Earth ground was first applied to a tuned circuit by the man RQ> created synthetic lightning. The same man who invented RQ> broadcasting, and a ground based electrical transmission RQ> system which requires no wires. How could you say that the RQ> followers of the man who first calculated these figures RQ> would be ignorant of his work? I will refer you first to RQ> Tesla's own writings: Colorado Springs Notes, 1899-1900, RQ> Nickola Tesla, Nolit, Beograd, Yugoslavia, 1978, pp12. Does this cover calculations of effective ground resistance or load impedance of arc current? I would think that would be more challenging to estimate, never mind measure accurately, than the more steady state RF values broadcasters measure, or DC or 60 Hz values electrical utilities check. If I could just absorb the details of about 1,500 manual pages on HP and Tek Spectrum analyzers I'm comparing without more eye overload, I might even be tempted to see what the local or interlibrary loan folks had available. (I do too much reading, but very little "pleasure" reading, outside a few echos, these days.) No... You have tempted me; I just can't predict what month I may next look through a library catalog, other than at a government documents center. RQ> pp36-37 entries for mid-month, June 15-17, 1899. Tesla RQ> proceeds to construct a system ground for the oscillator, RQ> followed by electrical measurement of both the system ground RQ> and the water pipe main supplying the lab. In later work all RQ> of the major earth resonate frequencies were plotted with RQ> amazing accuracy. The Wouldn't this be subject to dynamic change under the arc loading conditions of a large Tesla coil? RQ> O'scope had to wait years to be invented. In the 1950's RQ> Schumann, Despite the deficiencies we're able to find in them, I'm still curious what would show on a spectrum analyzer with antennas or probes comparing radiated and induced fields, near and distant. Did Tesla ever use older wave analyzers, or similar tunable resonant metering, to study the nature of signals from his coils? TS> For those larger coils, I would suspect an array of radials TS> using a few miles of #10 soft drawn Cu, with Erico TS> welded mesh for about 50' in the center, bonded with 4" TS> strap, might be adequate in most places. Add a couple of TS> 30' chemical grounding electrodes in poor soil areas. Does RQ> I ground my stuff to a buried hydraulic lift. The lift RQ> assembly consists of a large buried oil tank, air tank, RQ> supply and control plumbing, and the actual steel piston RQ> assembly. Run from this ground point (which is all metal RQ> spread out over 225 square feet) are two 1" ground straps; RQ> one strap runs to connect buried decorative pond (1500 RQ> gallon galvinized steel tank), the second runs to a 50' RQ> length of 14" wide aluminum flashing submerged in a nearby RQ> creek bed. I wonder what kind of reaction I'd get if I spec'd something like that in an engineering report for a client or the FCC? I bet you'd find it "interesting" to try evaluating the effective ground impedance of that distributed system over DC to MF RF! How long have you had that system in place? As a hobbiest, surplus materials are useful. If I had to maintain the integrity of such a system over years, there are a few major concerns. Copper is good for grounds because it tends to replace Hydrogen, whereas Hydrogen replaces Aluminum. Therefore, aluminum in outdoor electrode exposure can turn to Al(OH)2 + H2 pretty easily over time, while copper stays stable for 5 to 50 years. Cu can easilly be brazed with Cu-Ph or Cu-Ag + flux. Al cannot readilly be brazed, isn't practical to MIG weld outdoors or between thin strap and heavy iron, and so results in junction electrolysis problems mitigated primarily through either repeated mechanical cleaning, or doped electricians grease (No-Alox, etc.). In the long run, these factors make Cu ground systems less expensive in most applications, where labor and reliability have a cost associated with the system. Do you know what kind of typical ground conductivity is characteristic in your area? If not, maybe I'll compare your Origin location and an FCC soil conductivity map next time I have one out. Typical conductivity varies over a greater than 100:1 range around the US, exclusive of ocean areas which could make it a 20,000:1 range. If you're near a creek, I'd guess you have good soil conductivity, unless the creek is a pool on a rocky hillside. (203)732-0575 BBS (1:141/1275) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-08-94 00:00 From: William Lipp To: Richard Quick Subj: Re: Electrical octives 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Quoting Richard Quick to Don Kimberlin <=- RQ> Could you please expand a bit on the relationship between RQ> 300 - 3000 Hertz and 3-1/2 octaves? Are there 1000 Hertz in RQ> an octave? I don't understand ... Blame it on my music RQ> teacher. Each octave (like from C to C on the piano keyboard) doubles the frequency. So Richard's 3-1/2 octaves are 300-600, 600-1200, 1200-2400, and a bit. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-08-94 14:28 From: Matt Ion To: Richard Quick Subj: Electrical Octives 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Richard Quick wore his fingers to nubs typing a message to Don Kimberlin: RQ> Could you please expand a bit on the relationship between RQ> 300 - 3000 Hertz and 3-1/2 octaves? Are there 1000 Hertz in RQ> an octave? An octave is a halving or doubling of frequency. One octave above 300Hz is 600Hz. Two octaves would be 1200Hz (one octave above 600). Three would be 2400Hz. And so on. RQ> I understand that a relationship of eighths and frequency RQ> exists, but I guess that my problem is that I have no RQ> musical talent, and I am at a complete loss as to how many RQ> Hertz make up an octave, or what the precise relationship is RQ> when spanning frequencies. I have a pretty clear There is no Hertz=Octaves, it's a matter of ratios. Just like dB. In fact, 600Hz "could" be described as being 3dB above 300Hz, although dB doesn't actually refer to the frequency spectrum :) But it gives you an idea of how it's calculated. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-09-94 21:56 From: Mark Logsdon To: Richard Quick Subj: Electrical Octives 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� DK> frequencies, and most are some random fraction. When you DK> consider that even only 300 - 3000 Hertz covers about 3-1/2 DK> octaves, you see that's an even more complex problem.... RQ> Could you please expand a bit on the relationship between 300 RQ> 3000 Hertz and 3-1/2 octaves? Are there 1000 Hertz in an RQ> octave? Every time you double a frequency, you have an octave. Using his example, let's begin with 300 Hz. Freq, Hz Octaves @ 300 Hz -------- --------------- 300 0 600 1 1200 2 2400 3 4800 4 9600 5 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-10-94 14:29 From: Andrew Bak To: Richard Quick Subj: Electrical Octives 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 An Octave is actually 12 semi tones,or 7 whole tones..not eight,you just count the same one twice..start off with a note,double its frequency,and you have found its next octave...eg a=440Hz,880Hz,1760Hz... youll notice that as you go up and up the range,that there is more space between octaves... there is onlyone octave between 4kHz and 8kHz ( a range of 4000Hz) but several more between 0Hz and 4kHz.over the same distance. Hope this helps (1:153/7040) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-12-94 19:10 From: Richard Quick To: Dave Halliday Subj: Tesla Coils,ballast 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez Dave Halliday to Richard Quick to Dave Halliday <=- RQ> DH> RQ|We were talking about external current limiting on RQ> DH> RQ|xfmrs... and then we sidetracked to spark gaps momentarily... RQ> I have a compressed air quenched gap that when fired at over RQ> 1000 watts (3, 12kv 30ma neons) requires hearing protection. RQ> ... pure performance and peak power... DH> Also, you had mentioned a fluid cooled gap - how's that one DH> going? Stalled. I have some short video clips of completed, de-bugged prototypes. The gaps were designed to operate in series, either stand alone with a bank of neons, or with a rotary gap on the pig. They are loud, but should quiet down as additional gaps are placed in line. The design is more economical on air, but still requires a hefty compressor. They will require a permanent enclosure with muffled exhaust. I have yet to complete a wet firing with the entire cooling system in place at the same time. All the major plumbing sections (pump, heat exchanger, manifolds, etc.) have been designed, and 90% of these components have been completed or purchased. I realized last fall after the gap idea began comming to fruition that these gaps really need a semi- permanent installation somewhere. By the time I fiddle with the gap mounts, air supply manifolds, oil loop (manifold/heat exchanger/pump/manifold/electrodes), I have to dissemble every- thing to meet the shared space requirments (stepfamily...hoo). I was ready to go with lab construction, cash, blueprints & credit in hand, and we were hit here with a 500 year flood last spring and summer that primarily affected commercial property. DH> I saw in one of the articles in Wireless World about the old DH> spark-gap transmitters where they had the gap located in a DK> separate enclosed brick building. Yup, I think that was the one you mailed to me last fall. I still have my photocopies. Marconi monster xmiter, all stolen ideas ineffectively applied... and yes the humongus slow moving rotary was housed in a non-flamable brick enclosure. Let's see... > November 1993 Electronics World + Wireless World, pp 937-942. > The spark that gave RADIO to the world, by George Pickworth add that to the references column,,,... Anyway the article shamelessly ignored all fact, "Marconi" this and "Marconi" that, and only mentioned Tesla once; but it did have clear photos and diagrams of what not to do... What was useful was the photos of the damped wave trains produced with authentic gap systems, and a good general explanation of spark gap types and functions. What just picked up my eye was a statement about the 300 kW Marconi coil: the antenna current is stated as 220 amperes (1916) which agrees perfectly with the statement Tesla made in 1916, and I took the liberty of quoting here just the other day. Tesla was producing antenna currents of 1000 amperes in 1900.... That puts Tesla's peak powers an order of magnitude greater than Marconi, a full 16 years earlier. DH> I will be starting with the stationary gap you told me about DH> - several lengths of copper tubing inside of the PVC pipe DH> with a fan blowing through it ... Yup, good gap. Simple, cheap, works great. Took me eight hours to build my first one. The GIF diagram of this gap and my airblast gap, along with construction info, is on the disk I mail out. My address was just posted the other day for those who are interested, and I am pretty sure I sent you a copy when I mailed the tape. You got those GIFs didn't you? DH> but I have visions of doing a rotary gap or one with a DH> pulsed compressed air. I had thought that a commercial DH> audio high-frequency horn driver could be used to "pulse" a DH> flow of air and by varying the frequency you could adjust DH> the timing... This is the stuff of TCBA articles. DH> There was an insert in my last copy of TCBA news for an DH> advertisement for a rotary gap.... Humm, might it be... Yes, do I tell them? Possible slander??? Should I... Humm??? I told a story here already once about a guy in NY who fired monster coils like mine... And he ended up building a wooden control cabinet; seems his metal cabinet kept burning his fingers when he touched the controls. His RF ground path? A single #10 solid that runs 75' from his breaker box to a 3' copper clad rod, AND the center tap on the step-down xfmr that supplies his shed.. His coils never could develop any real punch because of the limits his ground path placed on the system. I won't even go on about the safety and responsibility issues, but I don't doubt his fingers drew arcs from the controls... Well the same guy finally made some decent spark! Better ground? Try a 1/2 wave system that requires no hard grounding from the secondaries... Look around, see any bi-polar, two phase coil using synchronous gaps??? This is a great design if you can't ground. The coils will "beat" or resonate off of each other. Somebody like that would probably gloat that their rotary gaps are built like brick outhouses. If they don't quench with static gaps, and they run big coils, they need a good solid rotary to make the break. DH> I have heard that theaters used to have variable reactance DH> dimmers for their lights - don't know if any are available DH> or what their time-constants are but that would be another DH> avenue to explore... Sounds like an idea. I don't think the time-constants are going to be as important as current ratings. Like I said, you learn to drive it gently, or you add resistive ballast to smooth it out. RQ> Some people have cut a small wedge out of the toroid core RQ> on variable transformers when they are to be used as RQ> variable inductance. DH> Hmmmm... Maybe there could be a way to move a wedge in and DK> out of the toroid... Either that or rewind it with a DK> heavier guage of wire... This one I don't understand. Removing a wedge of the toroid core is done to alter the field flux through it. These toriod shaped cores with "shell" windings are designed for efficient, low saturation, current flow. If the core has a section removed, a la cutting a wedge, the core will saturate some, but it is still too close to the "on-off" type control that an un-modified core gives. The idea is of course to end up with a variable inductive current limiter by placing the autoxfmr in series with the step up xfrmr primary. In Transtrom's book, ELECTRICITY AT HIGH PRESSURES AND FREQUENCIES (Henry L. Transtrom, orginal: 1913, 1921, J.G. Branch Publishing; Reprinted 1990, ISBN 1-55918-054-4, Lindsay Publications, Bradley, Illinois, 60915), I saw some decent ideas and explanations of inductive current limiters. I believe that the best design for variable inductive ballasting of Tesla coil xfmrs would be based on a simple "bar" core. There is no need to step up or down if you already have a good Powerstat or three, what you need is something that chokes down the current. I good variable bar inductor I would think to be ideal. I would guess that 30-40 lbs. or so of soft iron wire could be cut into equal straight sections. I would coat them in secondary coil sealer (p'urethane or epoxy). Don't ask me why I wander here. I think that a combination of ABS and thin wall PVC plastic pipe in ~4" diameters can be bought so as to make two 30" telescoping tubes. A smaller center tube would be packed with the insulated wire sections to form a bar type iron core, ~4" in diameter and say 30" long. The outer tube would serve as a coilform for a heavy coil. Guessing.. maybe 150 or so turns of enameled or poly coated bare #6 for the coil. Remember... This is all off the very top of my head here... Inductance can then be varied by sliding the center tube, containing the iron wire core, in and out of the slightly larger coil; this would be a sliding bar type inductor. The core and coil could be permanently wound together, then coil can be tapped; but all in all I think I would prefer the smooth, non- sparking variable inductance that a sliding core would give. I have never done this, and my thrown out figures are for example only, I am sure it is loaded with design errors. I only maintain that the idea is quite sound. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-10-94 22:10 From: Don Kimberlin To: Richard Quick Subj: About Octaves 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� ...To try to simplify that rambling answer about understanding octaves as used in electrical communications work, I should have read the dictionary first. However, after sending off that hip-shot of a reply, I did. The Webster's has a good long definition that shows several forms of references to the root "oct" relating to eights and eighths, of course. But when it gets down to around Meaning Number 5, it finally says: "..."the eighth full tone above a given tone, having twice as many vibrations per second, or below a given tone, having half as many vibrations per second." ...When using the term in electrical communications, the fact that musical scales divide the interval into eight steps is not considered. Hope that makes it very clear. (704)792-9241 (1:379/37) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-13-94 16:09 From: Richard Quick To: All Subj: Electrical Octaves 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� For Matt, Mark, Andrew, Bruce, and the others who replied to me in this thread; THANKS!!!!! All of your explanations, and the time taken to jot them down, was greatly appreciated. I have a pretty good handle on the subject now that it has been clearly and concisely put forward. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-13-94 10:24 From: Dave Halliday To: Richard Quick Subj: Tesla Coils,ballast 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Hi Richard! RQ|and then we sidetracked to spark gaps momentarily... RQ> I have a compressed air quenched gap that when fired at over RQ> 1000 watts (3, 12kv 30ma neons) requires hearing protection. RQ> ... pure performance and peak power... DH> Also, you had mentioned a fluid cooled gap - how's that one DH> going? RQ|Stalled. I have some short video clips of completed, de-bugged |prototypes. The gaps were designed to operate in series, |either I'll have to send you another ten bucks and a blank tape to see what you have been up to recently! I should be ready to fire sometime in the next month or so myself and have been documenting the ( slow sometimes stalled myself ) construction on video. |began comming to fruition that these gaps really need a semi- |permanent installation somewhere. By the time I fiddle with |the gap mounts, air supply manifolds, oil loop (manifold/heat |exchanger/pump/manifold/electrodes), I have to dissemble |everything to meet the shared space requirments |(stepfamily...hoo). I know the feeling - I also have a small home music studio and my previous house did not have enough room for a permanent setup... Setting the stuff up and tearing it down afterwards was such a pain that I didn't set things up unless I was feeling really productive... I have it permanently set up in my basement now - much better! RQ|I was ready to go with lab construction, cash, blueprints & |credit in hand, and we were hit here with a 500 year flood |last spring and summer that primarily affected commercial |property. I was wondering if you got caught in that one! We have similar problems in areas of the NW - especially since all the logging has removed the groundcover and all the rain just rolls off into the valleys. Couple this with the new building on the flood-plain and we have some problems every few years. DH> I saw in one of the articles in Wireless World about the old DH> spark-gap transmitters where they had the gap located in a DK> separate enclosed brick building. RQ|Yup, I think that was the one you mailed to me last fall. I |still have my photocopies. Marconi monster xmiter, all stolen |ideas ineffectively applied... and yes the humongus slow |moving rotary Yeah - that was my impression too... |completed or purchased. I realized last fall after the gap |idea was housed in a non-flamable brick enclosure. Let's see.. The brick enclosure was what caught my eye - maybe some sort of enclosure for the gap but then again, you want to keep it close to the coil to keep your "Q" nice and high... DH> I will be starting with the stationary gap you told me about DH> - several lengths of copper tubing inside of the PVC pipe DH> with a fan blowing through it ... RQ|Yup, good gap. Simple, cheap, works great. Took me eight hours |to build my first one. The GIF diagram of this gap and my Yeah - about what it took me too... Little buggers are slippery when you bed them into the epoxy! I used some spacers so they came out OK and I bet I could crank them out in about an hour after building a few... |airblast gap, along with construction info, is on the disk I |mail out. My address was just posted the other day for those |who are interested, and I am pretty sure I sent you a copy |when I mailed the tape. You got those GIFs didn't you? I got the GIF files - Thanks! 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-13-94 10:35 From: Dave Halliday To: Richard Quick Subj: Tesla Coils,ballast 1/2 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ| DH> but I have visions of doing a rotary gap or one with a | DH> pulsed compressed air. I had thought that a commercial | DH> audio high-frequency horn driver could be used to "pulse" | DH> a flow of air and by varying the frequency you could | DH> adjust the timing... RQ|This is the stuff of TCBA articles. I was thinking the same thing! The driver ( called a Compression Driver ) is designed to be placed at the throat of an exponential horn. It is used to working in a very high-pressure / low volume environment and I bet that if you kept the path small ( less than one wavelength ) and the plumbing rigid, you could get some nice disruptive pressure waves at your gap. RQ| DH> There was an insert in my last copy of TCBA news for an | DH> advertisement for a rotary gap.... RQ|Humm, might it be... Yes, do I tell them? |Possible slander??? Should I... Humm??? Slander??? Naaaaa.... :-) RQ|I told a story here already once about a guy in NY who fired |monster coils like mine... And he ended up building a wooden |control cabinet; seems his metal cabinet kept burning his |fingers when he touched the controls. His RF ground path? A |single #10 solid that runs 75' from his breaker box to a 3' |copper clad rod, You had talked about that one! Talk about not seeing the forest for the trees!!! sheesh... Probably had a lot of friendly neighbors too - especially the ones with TVs and AM radios... |fingers drew arcs from the controls... Well the same guy |finally made some decent spark! Better ground? Try a 1/2 wave |system that requires no hard grounding from the secondaries... |Look around, see any bi-polar, two phase coil using |synchronous gaps??? This s a great design if you can't |ground. The coils will "beat" or resonate off of each other. |Somebody like that would probably gloat that their rotary gaps |are built like brick outhouses. If they don't quench with |static gaps, and they run big coils, they need a good solid |rotary to make the break. Hmmm... I will have to go back and look to see the location of the person who was advertising the gaps... It wouldn't be anywhere NY would it??? Actually, getting off on a tangent here - I was wondering about a two coil setup where you wouldn't need a ground... I was thinking especially for a small portable system where you would not have a ground available to you and didn't want to blitz the neighborhood with RF... DH> I have heard that theaters used to have variable reactance DH> dimmers for their lights - don't know if any are available DH> or what their time-constants are but that would be another DH> avenue to explore... RQ|Sounds like an idea. I don't think the time-constants are |going to be as important as current ratings. Like I said, you |learn to drive it gently, or you add resistive ballast to |smooth it out. Yeah - that is why I was thinking the lighting system - they are rated for 20 / 30 mps or so... RQ| RQ> Some people have cut a small wedge out of the toroid core | RQ> on variable transformers when they are to be used as | RQ> variable inductance. DH> Hmmmm... Maybe there could be a way to move a wedge in and DK> out of the toroid... Either that or rewind it with a heavier DK> guage of wire... RQ|This one I don't understand. Removing a wedge of the toroid |core is done to alter the field flux through it. These toriod |shaped cores with "shell" windings are designed for efficient, |low saturation, current flow. If the core has a section |removed, a la cutting a wedge, the core will saturate some, |but it is still too close to the "on-off" type control that an |un-modified core gives. The idea is of course to end up with a |variable inductive current limiter by placing the autoxfmr in |series with the step up xfrmr primary. OK - I was just wondering if you could pass more or less of the magnetic flux and drive the core into saturation... RQ|In Transtrom's book, ELECTRICITY AT HIGH PRESSURES AND |FREQUENCIES (Henry L. Transtrom, orginal: 1913, 1921, J.G. |Branch Publishing; Reprinted 1990, ISBN 1-55918-054-4, Lindsay |Publications, Bradley, Illinois, 60915), I saw some decent [S]ave button time again! |ideas and explanations of inductive current limiters. |I believe that the best design for variable inductive |ballasting of Tesla coil xfmrs would be based on a simple |"bar" core. |Don't ask me why I wander here. I think that a combination of |ABS and thin wall PVC plastic pipe in ~4" diameters can be |bought so as to make two 30" telescoping tubes. A smaller |center tube would ... RQ|Inductance can then be varied by sliding the center tube, |containing the iron wire core, in and out of the slightly |larger coil; this would be a sliding bar type inductor. The |core and RQ|I have never done this, and my thrown out figures are for |example only, I am sure it is loaded with design errors. I |only maintain that the idea is quite sound. Nice idea! Sounds "right" to me too... 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Date: 07-13-94 20:48 From: Richard Quick To: Dave Halliday Subj: Tesla Coils,gaps 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 ... Dave came up with a unique idea for a sonic quenched gap! DH> I had thought that a commercial audio high-frequency horn DH> driver could be used to "pulse" a flow of air and by varying DH> the frequency you could adjust the timing... This really is the stuff of TCBA articles. The more I thought about this... Humm... Asumming that a break is made to discharge the capacitor at least every half cycle, then the bottom end pulse rate would be 120 pulses per second; 60 cycle current being common and there being two discharges per cycle. Now when you increase the current you can step up the break rate to 300-500 bps (breaks per second) by using some form of mechanical break, and get more spark from a system. Over 500 bps, and performance begins to drop off in most 1/4 wave systems. So you would probably want to generate pulses with a variable rate from about 100-500 pps (pulses per second). As far as audio goes, I believe this is pretty low frequency. But the duration of each pulse could allow for high frequency modulation... If you are just talking about efficiently moving air, you may find a low frequency "woofer" type speaker driven by a simple amplified pulse signal may be sufficient. Put the speaker cone in a mount that concentrates the moving air into the gap. Experi- ments with using pulses that are modulated high frequency audio could be tried to see if high frequency assists in quenching. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-14-94 21:39 From: Richard Quick To: Dave Halliday Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� DH> RQ|and then we sidetracked to spark gaps momentarily... DH> Also, you had mentioned a fluid cooled gap - how's that one DH> going? RQ| Stalled. I have some short video clips of completed, DH> I'll have to send you another ten bucks and a blank tape to DH> see what you have been up to recently! Nahh, I couldn't charge you for anything. What I have on tape recently is not long enough, or exciting enough, to make postage costs and mailing worthwhile. Too slow, too short. My problem was I started videotaping much too late in my work. I burned up, exploded, melted, arc punctured, and generally just trashed what would by now be a nice sized pile of handcrafted and surplus Tesla components... But it was hours and hours of coiling fun, and by far the most educational experimentation I have ever done. I have graphically seen things corona losses, VSWR, resonance and resonators, RF xmission lines, ground currents, mutual inductance,...the list goes on and on... There were dozens of "lashed up" experiments, none recorded on video. By the time video recording began I guess I had spent close to $5000, and already had a pretty good idea of what I was doing with coils, and what the coils were doing. DH> I should be ready to fire sometime in the next month or so DH> myself and have been documenting the ( slow sometimes DH> stalled myself ) construction on video. Get all the powerups, even the mistakes(especially the mistakes?) on tape. You will find the camera much more objective, and the coils photograph beautifully. Besides that, I wanted the chance to give you the ten bucks back... RQ> I was ready to go with lab construction... RQ> and we were hit here with a 500 year flood... DH> I was wondering if you got caught in that one! No personal loss, but new federal and local legislation, building codes, insurance, etc. relating to flood prone areas, (even areas not flooded in a 500 year flood) are limiting commercial develop- ment. Higher ground is not subject to this action, but has gotten considerably more valuable, and expensive. DH> We have similar problems in areas of the NW - especially DH> since all the logging has removed the groundcover... Our two big rivers bring water from many states. ... and about the spark gaps for the 300 kW Marconi xmittr. DH> The brick enclosure was what caught my eye... Those were huge gaps. I imagine the brick enclosure would have been about the right size for the first group tanning bed... :-) Most main gap systems should be enclosed, muffled and ducted, or at least shielded. The gases produced by the electric arcs are toxic and require "adequate ventilation"; so if you can't ventilate, you should at least duct to the outside. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-12-94 12:48 From: Don Kimberlin To: Richard Quick Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> DK> ...Mike Procospo wrote to all: RQ> MP> I'm interested in making a telsa coil... RQ> DK> ...Looks like it's time to rewind the tape and start it RQ> DK> over Richard RQ>Well it really isn't that bad. By now I have stored text files RQ>where I save my "Top Ten Tesla Requests", and what took hours RQ>to put together the first time can be cut, pasted, and revised RQ>if needed in a few minutes. ...Sounds like you may be called upon to run a "Tesla Top Ten FAQ" once a month or so.... RQ>Tesla is becoming an area of popular interest. ... ...Does seem to be having a resurgence after almost going totally quiet, doesn't it? His methods may yet get vindicated... RQ>I do appreciate RQ>the time that you and others have given towards intelligent RQ>input. Without quality people like yourself out here (and more RQ>joining in all the time) posting would be a waste of time. ....SET CLOYING_BLUSH.SYS /on ...Merci, Monsieur. Vous etes tres gentille... Concord,N.C. (704)792-9241 (1:379/37) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-14-94 10:39 From: Dave Halliday To: Richard Quick Subj: Tesla Coils,gaps 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ|... Dave came up with a unique idea for a sonic quenched gap! RQ| DH> I had thought that a commercial audio high-frequency horn | DH> driver could be used to "pulse" a flow of air and by | DH> varying the frequency you could adjust the timing... RQ|This really is the stuff of TCBA articles. The more I thought |about this... Humm... Yeah - my little grey cells have been 'a churning too... RQ|Asumming that a break is made to discharge the capacitor at |least every half cycle, then the bottom end pulse rate would |be 120 pulses per second; 60 cycle current being common and |there being two discharges per cycle. Now when you increase |the current you can step up the break rate to 300-500 bps |(breaks per second) by using some form of mechanical break, |and get more spark from a system. Over 500 bps, and |performance begins to drop off in most 1/4 wave systems. OK - so 600 bps would be the top limit then ( allowing room for experimentation ) This would be in the range of some of these drivers. For large arenas ( stadiums etc... ) they have horns that cover the low end pretty well falling off at 100 or so. RQ|So you would probably want to generate pulses with a variable |rate from about 100-500 pps (pulses per second). As far as |audio goes, I believe this is pretty low frequency. But the |duration of each pulse could allow for high frequency |modulation... Right! I was thinking of using a phase-lock-loop that could sample the actual frequency of the coil or of the power line. It would trigger a circuit ( 'nother 8051 CPU? ) that would generate the pulse-train for the horn driver. RQ|If you are just talking about efficiently moving air, you may |find a low frequency "woofer" type speaker driven by a simple |amplified pulse signal may be sufficient. Put the speaker cone |in a mount that concentrates the moving air into the gap. |Experiments with using pulses that are modulated high |frequency audio could be tried to see if high frequency |assists in quenching. The mount would be the trick. It would need to be a reverse exponential horn and you would need a phasing plug in it to compensate for the different path-lengths from different areas of the cone. The good news is that the design for this has been worked out for the horns, it just needs to be worked in reverse for a speaker. | ! Origin: Cindex Support BBS (314) 837-5422 Florissant, MO. (1:100/395.0) ^^^^^^^^^^ You ought to check with the town government if they might be interested in renaming it to "Florescent" You probably have it glowing in the dark by now anyway... TTYL - dave 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-15-94 08:55 From: Dave Halliday To: Richard Quick Subj: Tesla Coils 1/2 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 RQ| DH> RQ|and then we sidetracked to spark gaps momentarily... |costs and mailing worthwhile. Too slow, too short. My problem |was that I started videotaping much too late in my work. I |had already burned up, exploded, melted, arc punctured, and |generally just trashed what would by now be a nice sized pile |of handcrafted and surplus Tesla components... I have a bunch of other stuff I worked on that I wish I had documentation on for now... I got the video stuff so that I could make training tapes for the store and I only recently got the idea to document the stuff at home... I can imagine the piles and piles of exploded, melted, arc punctured... stuff! I am very much looking forward to generating a similar pile of my own!!! RQ|But it was hours and hours of coiling fun, and by far the most |educational experimentation I have ever done. I have |graphically seen things corona losses, VSWR, resonance and |resonators, RF xmission lines, ground currents, mutual |inductance,...the list goes on and on... There were dozens of |"lashed up" experiments, Nothing like running a few KVA through something to make it visible to the unassisted eye :-) |none recorded on video. By the time video recording began I |guess I had spent close to $5000, and already had a pretty |good idea of what I was doing with coils, and what the coils |were doing. RQ| DH> I should be ready to fire sometime in the next month or | DH> so myself and have been documenting the ( slow sometimes | DH> stalled myself ) construction on video. RQ|Get all the powerups, even the mistakes (especially the |mistakes?) on tape. You will find the camera much more |objective, and the coils photograph beautifully. Besides |that, I wanted the chance to give you the ten bucks back... You bet! Especially the mistakes - those ( even the expensive ones ) can be a lot of fun after a few days to "recover" Looking back in retrospective - Hooo boy... Was I *stupid* or what... RQ| RQ> I was ready to go with lab construction... | RQ> and we were hit here with a 500 year flood... RQ| DH> I was wondering if you got caught in that one! RQ|No personal loss, but new federal and local legislation, |building codes, insurance, etc. relating to flood prone areas, |(even areas not flooded in a 500 year flood) are limiting |commercial development. Higher ground is not subject to this |action, but has gotten considerably more valuable, and |expensive. In order to really screw something up, get the government involved... The legislature was probably heavily lobbied by the insurance industry so they passed laws favoring them... :-( Don't want to insure commercial buildings that might stand a higher chance of getting damaged - instead, lets just not build them! RQ|... and about the spark gaps for the 300 kW Marconi xmittr. RQ| DH> The brick enclosure was what caught my eye... RQ|Those were huge gaps. I imagine the brick enclosure would have |been about the right size for the first group tanning bed... |:-) Yeah - lots'a UV kicking around too - burn to a crisp after a few sessions! I do commercial printing ( plus computers and such ) at the store and have a mercury arc plate burner. You do not want to stand close to that when it is running! Also, a friend of mine and I went in on a welding setup - MIG wire welder and torches. Found out that all of the protective clothing is for UV as well as dingleberries! I wear sandals and got a nice sunburn on the top of my feet after one afternoon spent turning small scraps of metal into bigger scraps... |Most main gap systems should be enclosed, muffled and ducted, |or at least shielded. The gases produced by the electric arcs |are toxic and require "adequate ventilation"; so if you can't |ventilate, you should at least duct to the outside. Hmmmm... Makes a lot of sense! NO2 and all that wonderful reactive stuff - there is an outside garage window right near where I will be mounting the pole-pig and power control so I'll just run some PVC pipe out through a panel. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-16-94 08:17 From: Richard Quick To: Mark Logsdon Subj: Swr's On My Base 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 ML> This might be semantic, but the power is not reflected. I ML> know, I know, that's what people typically say, but it's the ML> VOLTAGE that's reflected, and the difference CAN be ML> significant. ML> It is possible to not deliver any power at all into a ML> transmission line (assuming a lossless line), yet have a ML> high VSWR. I think you meant: you can put plenty of power into a lossless line and still get no power out. Power is delivered (by the xmittr here), but little is radiated despite a high VSWR. ML> If you don't believe it, consider a transmitter with a trans- ML> mission line connected to a perfect capacitor or inductor. ML> Think about it. That will give you an infinite VSWR. You can ML> get the same result by attaching a transmission line of a 1/4 ML> wavelength that is either shorted or open. Ideal Tesla coil experiment! This is a Tesla coil! ML> A shorted 1/4 wave line will be an inductor; an open 1/4 ML> wave line will be a capacitor. If a 1/4 wave length line is wound into a coil, it will be a good inductor, and also have some capacitance. Capacitance can be added by loading the coil with a capacitive air terminal. ML> Key your transmitter into either and you'll transmit ZERO ML> power, but you will produce a voltage. With a simple, slow 1/4 wave, helical transmission line (Tesla coil) you have both inductance and capacitance. You get a very substantial voltage, you transmit near ZERO power. Seems we agree that transmission in this context means "radiated signal". ML> What will your VSWR meter read?... Infinity. The is the same as the theoretical voltage of a lossless coil. ML> (Plot it on a Smith Chart.) The Corums do a fairly excellent job of this in their book > VACUUM TUBE TESLA COILS published by James and Kenneth Corum, 8551 State Route 534, Windsor, Ohio, 44099, USA. The Smith Chart of the C.S. Extra Coil is on the cover. ML> But you say that it's delivering power. No, it's not. ML> Power is not created, nor is it destroyed; it is never even ML> transmitted in this case. It's an important distinction. You are absolutely correct, but don't lose sight of the fact that something unique is happening, even though the radiated signal strength is going to be very low even in a lossy line. ML> Think of it in the sense of having a 60 Hz AC signal and ML> installing a pure inductor across that signal. You have ML> voltage. You have current. But the voltage and current are ML> 90 degrees out of phase. You are delivering zero power. ML> None is created. None is destroyed. None is reflected. ML> It's just simply not delivered. It's the same principle ML> with RF and transmission lines. The same with a Tesla coil, and the coil makes a very (possibly the most) graphical demonstration of this. The air terminal, or "open end" of a coil is the 1/4 wave voltage peak. At the base of the coil you find a heavy current at ground potential. A probe connected with the coil base can be used to draw spark (voltage) from the side of a small unsealed coil, the spark getting longer the higher up the coil you go. At the base of the coil, ground path currents may be detected and measured with something as simple as a current transformer/ammeter, a frequency matched (tuned) 1/4 wave "pickup coil", or even bulbs. Restating: the base of the coil is zero degrees, it is very low voltage, high current: the top of the coil is 90 degrees (1/4 of a wave), low current, high voltage. It is a perfect example. ML> I hate it when people use the term "reflected power,"... I can understand that, too. I don't see any "reflection" at all. Thanks for posting your thoughts on this. I hope you don't mind me throwing out my slant. With a slightly different vocabulary we are both talking about exactly the same thing. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-16-94 16:07 From: Richard Quick To: Dave Halliday Subj: Tesla Coils,gaps 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 DH> RQ| Dave came up with a unique idea for a sonic quenched gap! DH> I had thought that a commercial audio high-frequency horn DH> driver could be used to "pulse" a flow of air and by varying DH> the frequency you could adjust the timing... RQ|This really is the stuff of TCBA articles. The more I thought |about this... Humm... DH> Yeah - my little grey cells have been 'a churning too... RQ|Asumming that a break is made to discharge the capacitor RQ|at least every half cycle, then the bottom end pulse rate RQ|would be 120 pulses per second... Now when you increase the RQ|current you can step up the break rate to 300-500 bps... RQ|Over 500 bps, and performance begins to drop off in most RQ|1/4 wave systems. DH> OK - so 600 bps would be the top limit then ( allowing room DH> for experimentation ) Unless you are moving into more advanced circuits, like a balanced Magnifier circuit where you can utilize bps of over 1000, then 100-600 bps is a good range. DH> This would be in the range of some of these drivers. For DH> large arenas ( stadiums etc... ) they have horns that cover DH> the low end pretty well falling off at 100 or so. Price anyone? DH> Right! I was thinking of using a phase-lock-loop that could DH> sample the actual frequency of the coil or of the power DH> line. It would trigger a circuit ( 'nother 8051 CPU? ) that DK> would generate the pulse-train for the horn driver. I just don't know. With Tesla tank circuit currents (and peak powers), I don't think I would expect too much in the way of performance and reliability from solid state sensor/trigger components. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-15-94 14:43 From: Johnny Stevens To: Richard Quick Subj: Something fun 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� I would be interested in any kind of high-voltage stuff you may have. I have built several Tesla coils myself, and am very much interested in making more. What's this tape I keep reading about. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-18-94 23:04 From: Mark Logsdon To: Richard Quick Subj: Swr's On My Base 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� ML> This might be semantic, but the power is not reflected. ML> I know, I know, that's what people typically say, but it's ML> the VOLTAGE that's reflected, and the difference CAN be ML> significant. ML> It is possible to not deliver any power at all into a ML> transmission line (assuming a lossless line), yet have a ML> high VSWR. RQ> I think you meant: you can put plenty of power into a RQ> lossless line and still get no power out. Power is delivered RQ> (by the xmittr here), but little is radiated despite a high RQ> VSWR. No, not really. If the power is not being dissipated or radiated, then it's not entering the line -- period. Power doesn't enter the transmission line, decide it has not place to go, and decide to go back home to the transmitter. You are correct, however, that the line should be lossless if no power is to be delivered to the line. Think of the example with the pure inductor (or capacitor) attached to an alternating voltage source. There is no power delivered. No power ever leaves the source. There is, however, voltage and current leaving the source, but since it's out of phase, there is not any power delivered. ML> If you don't believe it, consider a transmitter with a trans- ML> mission line connected to a perfect capacitor or inductor. ML> Think about it. That will give you an infinite VSWR. You can ML> get the same result by attaching a transmission line of a 1/4 ML> wavelength that is either shorted or open. RQ> Ideal Tesla coil experiment! This is a Tesla coil! Yep, and it's not any different than a transmission line connected to a load. You could have used a transmission line to connect the voltage source to the Tesla coil. Unfortunately, the term "reflected power" is used incorrectly and causes lots of confusion. It's the voltage that's reflected. The term "reflected power" can be thought of as a comparison of sorts. Look at the forward voltage, and imagine how much power it could have provided in a characteristic load, e.g., 50 ohms. Then do the same with the reflected voltage, and you'll see how much power it lost you. Yet, the forward and reflected voltage really never represented any power at all, because none was ever delivered to the system. Power never entered the transmission line. It's like a length of pipe already filled with water that has a closed valve on one end. Let's say you have a pressure from a source of additional water applied to the pipe. If you don't open the valve, you'd say that no flow occurred. People would argue that there is water in the pipe, and while that's true, there is still no flow. We don't say that the flow enters the pipe, decides there is no place to go, and then decides to go back to its source, the water company. It's the same way with power if there's no resistive load; the power never enters the transmission line. To some people this is radical concept, but that is only because of the misuse of the terms that sort of ingrains these wrong ideas in our heads. I know, because I was guilty of this myself for many years. :) ML> Key your transmitter into either and you'll transmit ZERO ML> power, but you will produce a voltage. RQ> With a simple, slow 1/4 wave, helical transmission line RQ> (Tesla coil) you have both inductance and capacitance. You RQ> get a very substantial voltage, you transmit near ZERO power. RQ> Seems we agree that transmission in this context means RQ> "radiated signal". Ah, this is apparently a parallel resonant circuit. Right? ML> What will your VSWR meter read?... Infinity. RQ> That is the same as the theoretical voltage of a lossless RQ> coil. Agreed. ML> I hate it when people use the term "reflected power,"... RQ> I can understand that, too. I don't see any "reflection" at RQ> all. Thanks for posting your thoughts on this. I hope you RQ> don't mind me throwing out my slant. With a slightly RQ> different vocabulary we are both talking about exactly the RQ> same thing. I don't mind at all. It often helps me to understand things better when I try to explain it someone else. Do you yourself find this true? 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-19-94 15:44 From: Richard Quick To: Dave Halliday Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Dave, Been having a couple of feed problems here since the weekend of the forth. I try to go through every two weeks now to archive and organize the Tesla threads (you realized that just our posts alone make up a decent book)... Anyway, I missed sending you out part two of a post last week sometime. You asked about coil systems that don't require heavy RF ground- ing of the secondary, and that do not radiate appreciable RFI. You mentioned that coils of this type would be ideal for demon- strations at locations away from the dedicated RF grounding system available in the lab. You were of course using your head again, and most likely perceived the dangers of crossing ground connections of say, a 3 KVA coil system (powerful enough to raise eyebrows at the back of an auditorium), and something like say a $50,000.00 school computer system. The worst I have seen to date has been a system reboot caused from a coil discharge striking a ground. Since the computer was common grounded 30' away from where the coil was operated, and the coil was a small commercial vacuum tester that only generated 3/4 of an inch of spark on a dry day (you have heard of those in Seattle?), I realized how sensitive computers are to ground path contamination from Tesla coils. If you can verify that the Tesla ground is dedicated, then you won't have problems like this unless the coil is striking at breaker boxes, 60 cycles lines, conduit, etc.. To my knowledge there are at least two Tesla coil systems that do not require dedicated grounded secondaries. Bi-polar coils, and bi-phase coils. A bi-polar coil is made with a single Tesla secondary. The bi- polar secondary is typically mounted sideways, the primary coil centered on the secondary, and both ends of the secondary coil are left open (air terminals). This is characterized as a half wave coil. The center of the secondary becomes zero degrees (nul voltage) with two 1/4 wave or 90 degree voltage peaks appearing at the air terminals. There is no ground required here, and Tesla used this design with great effect in his lectures. The bi-phase system is more complex, but yields much greater point to point spark lengths. Two secondaries are constructed to be identical, with the exception that the windings are in the opposite direction. Two primaries are similarly constructed. The system is set up as two 1/4 wave coils, but with the primaries placed in series in the same tank circuit. Being of opposite polarity, the ground currents should theorectically cancel... I built on once about two years ago. The coils entered a fearsome battle despite my repeatedly shutting things down and moving them farther and farther apart. Before I even found out how long the sparks were going to get; one coil form was holed, the other broke down internally (about 8' separation, 3KVA, oh what video this would have made...). Anyway, that was before I was using large toroids and hermetically sealed secondary coil forms (I USED to run the wire inside the coil form...) But back to the point... I still think a safety gap should be incorporated into the back end of the tank circuit... And how would you go about grounding that??? 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-18-94 08:28 From: Dave Halliday To: Richard Quick Subj: Tesla Coils,gaps 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 RQ|DH> RQ| Dave came up with a unique idea for a sonic quenched RQ|DH> RQ| gap! DH> I had thought that a commercial audio high-frequency horn DH> driver could be used to "pulse" a flow of air and by varying DH> the frequency you could adjust the timing... RQ|Asumming that a break is made to discharge the capacitor RQ|at least every half cycle, then the bottom end pulse rate RQ|would be 120 pulses per second... Now when you increase the RQ|current you can step up the break rate to 300-500 bps... RQ|Over 500 bps, and performance begins to drop off in most RQ|1/4 wave systems. DH> OK - so 600 bps would be the top limit then ( allowing DH> room for experimentation ) RQ|Unless you are moving into more advanced circuits, like a |balanced Magnifier circuit where you can utilize bps of over |1000, then 100-600 bps is a good range. RQ| DH> This would be in the range of some of these drivers. For | DH> large arenas ( stadiums etc... ) they have horns that | DH> cover the low end pretty well falling off at 100 or so. RQ|Price anyone? Couple hundred bucks for the biggies - I would have to double check on the exact price. I think though that there should be surplus units available... Matter of tracking the source... DH> Right! I was thinking of using a phase-lock-loop that could DH> sample the actual frequency of the coil or of the power DH> line. It would trigger a circuit ( 'nother 8051 CPU? ) that DK> would generate the pulse-train for the horn driver. RQ|I just don't know. With Tesla tank circuit currents (and peak |powers), I don't think I would expect too much in the way of |performance and reliability from solid state sensor/trigger |components. I was thinking along the lines of picking the current-flow through the primary - that way, you could use a very low impedance sensor ( a few turns around the primary leadin ) that would generate enough current to light an LED - place this in a metal box and connect it to your controller via fiber... Stuff for future experimentation anyway... 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-19-94 15:44 From: Richard Quick To: Dave Halliday Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Dave, Been having a couple of feed problems here since the weekend of the forth. I try to go through every two weeks now to archive and organize the Tesla threads (you realized that just our posts alone make up a decent book)... Anyway, I missed sending you out part two of a post last week sometime. You asked about coil systems that don't require heavy RF ground- ing of the secondary, and that do not radiate appreciable RFI. You mentioned that coils of this type would be ideal for demon- strations at locations away from the dedicated RF grounding system available in the lab. You were of course using your head again, and most likely perceived the dangers of crossing ground connections of say, a 3 KVA coil system (powerful enough to raise eyebrows at the back of an auditorium), and something like say a $50,000.00 school computer system. The worst I have seen to date has been a system reboot caused from a coil discharge striking a ground. Since the computer was common grounded 30' away from where the coil was operated, and the coil was a small commercial vacuum tester that only generated 3/4 of an inch of spark on a dry day (you have heard of those in Seattle?), I realized how sensitive computers are to ground path contamination from Tesla coils. If you can verify that the Tesla ground is dedicated, then you won't have problems like this unless the coil is striking at breaker boxes, 60 cycles lines, conduit, etc.. To my knowledge there are at least two Tesla coil systems that do not require dedicated grounded secondaries. Bi-polar coils, and bi-phase coils. A bi-polar coil is made with a single Tesla secondary. The bi- polar secondary is typically mounted sideways, the primary coil centered on the secondary, and both ends of the secondary coil are left open (air terminals). This is characterized as a half wave coil. The center of the secondary becomes zero degrees (nul voltage) with two 1/4 wave or 90 degree voltage peaks appearing at the air terminals. There is no ground required here, and Tesla used this design with great effect in his lectures. The bi-phase system is more complex, but yields much greater point to point spark lengths. Two secondaries are constructed to be identical, with the exception that the windings are in the opposite direction. Two primaries are similarly constructed. The system is set up as two 1/4 wave coils, but with the primaries placed in series in the same tank circuit. Being of opposite polarity, the ground currents should theorectically cancel... I built on once about two years ago. The coils entered a fearsome battle despite my repeatedly shutting things down and moving them farther and farther apart. Before I even found out how long the sparks were going to get; one coil form was holed, the other broke down internally (about 8' separation, 3KVA, oh what video this would have made...). Anyway, that was before I was using large toroids and hermetically sealed secondary coil forms (I USED to run the wire inside the coil form...) But back to the point... I still think a safety gap should be incorporated into the back end of the tank circuit... And how would you go about grounding that??? 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-20-94 13:21 From: Dave Halliday To: Richard Quick Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 RQ|Dave, Hi Richard! |organize the Tesla threads (you realized that just our posts |alone make up a decent book)... Anyway, I missed sending you |out part two of a post last week sometime. Yeah - I have a couple hundred K unzipped - figure 4.5K per page and we are at about 50 pages single-spaced with no illustrations... Might be a good winter project here... RQ|You asked about coil systems that don't require heavy RF |grounding of the secondary, and that do not radiate appre- |ciable RFI. You mentioned that coils of this type would be |ideal for demonstrations at locations away from the dedicated |RF grounding system available in the lab. You were of course |using your head again... Right - some of my customers have commented on the TCBA bumper sticker in my store window and have seen me building some of the coils components at the store and I thought that it would be interesting to have a small table-top unit to scare away future clients... |and most likely perceived the dangers of crossing ground |connections of say, a 3 KVA coil system (powerful enough to |raise eyebrows at the back of an auditorium), and something |like say a $50,000.00 school computer system. The worst I have |seen to date I heard about someone who brought a "classical" Tesla Coil into one of the earlier Northwest Computer Fairs ( pre-MS/DOS ) and proceeded to nuke several systems... I would hate to think of what a properly designed unit would do under these conditions... Great for the repair business though... Hmmm... Get a step-van with a small generator, park it near the electrical panel for the buildings and then put a magnetic sign on the side - Computers Fixed... |has been a system reboot caused from a coil discharge striking |a ground. Since the computer was common grounded 30' away from |where the coil was operated, and the coil was a small com- |mercial vacuum tester that only generated 3/4 of an inch of |spark on a dry day (you have heard of those in Seattle?), I |realized how WOW! I am very familiar with those units and would not think that they could cause this amount of problems although considering that your 'puter thinks that 5-Volts is just right, applying even 5 more volts is less-than-healthy... I *have* heard about dry days - we have to go to Arizona to see them though. The mayors office usually sends his brother Ed there on a junket every year and he brings back some snapshots of the desert. All of Seattle gets together for dinner over tot he mayors house and we look at the pictures and dream... The constant rain is not too bad - whenever it stops, we have to continually mist down the mildew on our houses to keep it alive and the webbing between my fingers and toes gets really red and cracked.. Hurts like the blazes... RQ|To my knowledge there are at least two Tesla coil systems that |do not require dedicated grounded secondaries. Bi-polar coils, |and bi-phase coils. RQ|A bi-polar coil is made with a single Tesla secondary. The bi- |polar secondary is typically mounted sideways, the primary |coil centered on the secondary, and both ends of the secondary |coil are left open (air terminals). This is characterized as a |half wave coil. The center of the secondary becomes zero |degrees (nul voltage) with two 1/4 wave or 90 degree voltage |peaks appearing at the air terminals. There is no ground |required here, and Tesla used this design with great effect in |his lectures. hmmmm... RQ|The bi-phase system is more complex, but yields much greater |point to point spark lengths. Two secondaries are constructed |to be identical, with the exception that the windings are in |the opposite direction. Two primaries are similarly con- |structed. The system is set up as two 1/4 wave coils, but with |the primaries placed in series in the same tank circuit. Being |of opposite polarity, the ground currents should theorectic- |ally cancel... I built on once about two years ago. The coils |entered a fearsome battle despite my repeatedly shutting |things down and moving them farther and farther apart. Before |I even found out how long the sparks were going to get; one |coil form was holed, the other broke down internally (about 8' |separation, 3KVA, oh what video this would have made...). |Anyway, that was before I was using large toroids and |hermetically sealed secondary coil forms (I USED to run the |wire inside the coil form...) HMMMM!!!! This would definitely be something to see I think that the first one would be a nice place to start though - I was thinking of something that could be hauled around in a passenger seat of a car and set up in 10 minutes. Probably two neons for power although I would need to run Walt Noons program to get the actual specs... This would look visually interesting too because you could have two toroids - kind of an interesting form sculpturally as well as electrically... RQ|But back to the point... I still think a safety gap should be |incorporated into the back end of the tank circuit... And how |would you go about grounding that??? True - very true! Any sort of imbalance would cause current to flow on one leg of the circuit... I am just thinking now of maybe setting the coil up with a good ground and then determine a safe operating area where the safety gap does not fire and just keep it at that... Also, way off topic here but just met a really neat lady - have been hitting it off really well! Date that we met? July 10 - N. Tesla's B'Day! TTYL - Dave 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-20-94 21:12 From: Bruce Tolliver To: Richard Quick Subj: Electrical octaves 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ|>For Matt, Mark, Andrew, Bruce, and the others who replied to RQ>me in this thread; THANKS!!!!! I am glad you asked something I knew a little bit about. For that, you are very welcome, Richard. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-19-94 20:18 From: John Marsh Iv To: All Subj: Tesla Coil 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Does anyone have EXACT instructions on making a desktop size tesla coil, I have assisted in the building of larger ones, but I just want a little demo model. I will send you a large folder sized envelope stamped if you would netmail me your address at 1:3654/141. Thanks, BTW i am the sysop here so no one else would get hold of your address. (910)841-5646 (1:3654/141) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-23-94 15:07 From: Richard Quick To: John Marsh Iv Subj: Tesla Coil 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez John Marsh Iv to All <=- JMI> Does anyone have EXACT instructions on making a desktop JMI> size tesla coil... I just want a little demo model. Thank you John for your interest. I have reams of text files on this subject, and I post a two (soon to be three) part message in this conference every couple of weeks or so (it seems) with tons of references. Look for the two part post "Tesla,references" to "ALL" in today's mail packet for the 7/23/94 updated file. I design coils, and coil designing has been (and still is) extensively covered here, as well as; Tesla history, coil theory, component performance, construction materials, tips... You name it. For the last three weeks or so Dave Halliday and I have been discussing design parameters for a small bi-polar Tesla Coil for demonstrations where a proper ground is not available. I would need some specifics from you before I can tender any further information specifically taylored to your requirments. How many input watts? How large a secondary? JMI> I will send you a large folder sized envelope stamped if JMI> you would netmail me your address at 1:3654/141. Thanks... My address is posted here regularly if you wish to request files by mail. I have enough text on this subject to make up a pretty comprehensive book, and a couple of decent GIF schematics. FREE! > see: "Tesla,references" addressed to: "ALL", 7/23/94. Any other information (design changes, updates, Q & A, etc.) I can just ECHO to you here. Good Luck!!!! 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-23-94 15:45 From: Richard Quick To: John Marsh Iv Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� > From: Archives Date:10-10-93 From: Richard Quick To: David Bearrow Subj: 10KVA Tesla Coil 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 DB> How did you go about winding your coil? What are the specs? The first step in winding a coil is to select a coil form. The coil form should be a low loss material (we are talking RF losses) like polyethylene, polystyrene, or polypropylene: but the most common material is PVC plastic drain pipe (thinnest wall is best) which is high loss. I used a section of PVC thin wall duct. Ratios of coil height to width are important. Small coils work best with aspect ratios (height to width) around 5:1 - 4:1, larger coils (over 8" diam.) have aspect ratios around 3:1. Now we are talking about the actual winding length here, so allow an extra inch or so of coil form on each end. Determine the length required and cut the ends square. The form must be sanded smooth of surface imperfections, dried thoroughly, and if PVC is used, it must be sealed. A good sealer is polyurethane, another is two part epoxy paint. By sealing the surface of the PVC before you wind on wire you can negate the excessive losses in PVC plastic coil forms. If necessary the coil form may be sanded again after the sealer had dried. The coil should be wound with good quality magnet wire. I use double Formvar enamel coated magnet wire. Magnet wire gives you maximum inductance per unit volume. A coil should have over 900 turns, but not too much over 1000 turns. There is a little leeway here. Select a gauge of wire which will allow the aspect ratio and number of turns to fall within this range. I plug the ends of the coil form and run a dowel through a center hole so that it will spin. I set up the wire spool on one end of a pair of sawhorses, and the coil form on the other end. I wind the wire on by hand, making sure the windings are tight, smooth, and even. I use a dab of hot glue or tape to hold the first turns in place, and make sure to leave a tail of wire at either end. Once the coil is wound, it is sealed to prevent corona leakage and breakdown. I use the same sealers mentioned above. Coats of sealer are applied until there are no ridges and valleys in the wire. In other words the coats must build up until the wire is completely imbedded in sealer. The wound, sealed, coil is capped at both ends with plexiglas plates glued down with epoxy. I cut circles out of plexi sheet that is about the same thickness as the coil form. I rough up the surface around the edges to give the epoxy a bite. One small hole may be drilled into the bottom end plate to allow the air pressure to equalize, but under no circumstances should any other holes be drilled. The wire is never allowed inside the form. ---------------------------------------------------------------- Date: 21 Jun 94 From: Richard Quick To: Bob Patten Subj: Tesla Coils ----------------------------------------------------------------- BP> I'm a real novice at this and need to sort out a lot of BP> info and get a better understanding of it.... I wish I could recommend the definitive book on Tesla coiling, but I have read them all, and I still have not read IT. You can start by winding a 4" coil with a resonate frequency of around 450 kHz, or preferably a little higher. Get some rigid Plexi, Lexan, or polystyrene pipe/tubing with a thin wall. It should be ~4 inches in diameter and 21 inches long. Thin wall PVC drain pipe may be used but it must be sanded, dried throughly, and sealed with several coats of polyurethane or clear two-part epoxy paint. Buy at least 1-1/4 lbs (~1000 feet in length) of #24 double Formvar (enamel) covered magnet wire. Wind the wire on the coil form. The windings needs to be tightly spaced, no gaps, and no overlaps: the winding should start 1" above the bottom of the coil form. #24 magnet wire winds about 46 turns per inch (TPI), the winding should be 19 inches long with ~874 turns, and use up about 915 feet of the wire. The winding should stop about 1" below the top of the coil form. Use tape, hot glue, or clear epoxy to affix the top and bottom turns of the coil winding. Never drill holes or introduce wire inside the coil form. Once wound, the windings should be sealed with several coats of polyurethane or clear two-part epoxy paint. After the windings are sealed, I cap the top and bottom of the coil form with disks of plexiglass bedded in epoxy. This coil is modern. It offers the maximum inductance per unit volume of coil form in a high Q design. It will work very well in a spark, or tube, driven tank circuit of moderate power. ---------------------------------------------------------- END__ Is this something like what you were looking for???? If so, then look through the "Tesla,references" post to "ALL" in todays packet. These files are available from me on floppy, or by calling this BBS and downloading the file . If you needed any addition information, or stuff not already posted, please just drop me a note. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-23-94 17:20 From: Richard Quick To: Dave Halliday Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> I still think a safety gap should be incorporated into the RQ> back end of the tank circuit... And how would you go about RQ> grounding that??? DH> I am just thinking now of maybe setting the coil up DH> the safety gap does not fire and just keep it at that... RQ| Running in proper tune IS the best way to operate... RQ| It is after all a "safety gap". DH> True! I was trying to think of a way around the safety gap DH> and cannot... It would be fairly easy to block any RF from DH> feeding back into the neon but the overvoltage still needs DH> to go somewhere! DH> Maybe some kind of fusable link? Ahhh, you missed the beauty of the circuit I sent you several months back, and the same one used in the RF choke board in the video... The one with the high voltage bypassing capacitors... These caps are wonderful "shock absorbers" in the circuit. They really help in bleeding off excessive voltage, and assist (along with the safety gap) in protecting the step up xfrmr. If the coil is in tune, and the safety gap is set properly but not firing, the bypass caps will bleed off any spikes and smooth things out. > From archives 3/94 ----------------------------------------------------------------- �------� | | X1 RFC 1A 컴|컴컴컴|컴컴커붚컴컴컴쩡컴컴컴컫컴컴程程粘컴> TO TESLA TANK | | )�( � � | | )�( � � | | )�( BC1 컨� O | LF1 쳐� )�( 컫� o컴� SAFETY GAP | | )�( � O | | )�( � � | | )�( � � 컴|컴컴컴|컴컴켸봉컴컴컴좔컴컴컴컨컴컴훃UUUU컴�> TO TESLA TANK | | � RFC 1B �------� 賈� grnd LF1 is a commercial heavy duty line filter wired in reverse. Where current throughputs are high I use several in parallel. The Line Filters I use have RF choke coils in the ground path; the ground wire can be run reversed (it is neutral) and can be used to trap stray RF, preventing ground path contamination to the 60 cycle breaker box. The core of X1, and everything to the right of X1 in this diagram, is grounded separately to a heavy, dedicated, RF ground. BC1 is a Bypass Capacitor. I use high voltage barium titanate doorknobs, with stacks of four or more in series. A typical rating for a single cap would be .003 microfarad @ 30 KVDC, and using four of these caps in series I get .0007 microfarads at 120 KVDC. Since the AC rating is about half the DC rating on these type capacitors, figure a series stack of four will withstand a kickback of 50-60 KVAC in this use. Where center tap ground type xfrmrs are used for X1 (such as neon sign cores) BC1 must be divided into two units, and the center of the stack must be grounded with the xfrmr core (see the arrange- ment of PC1 and PC2 in the top most diagram). Use no more than .0008 or so microfarads per side, as too large a bypass capaci- tance will create an oscillating current in the high voltage windings on your step up xfrmr that will cause the xfrmr to fail. RFC 1A and RFC 1B are about 15-20 turns (minimum) of insulated wire on a large iron powder core. I use 2" diameter iron powder toroids to wind these chokes. -----------------------------------------------------------END__ When running this filter/choke/spike protection circuit, and the coil is in excellent tune, the safety gap does not fire. It is like it was not even there... 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 7-27-94 15:25 From: Richard Quick To: John Marsh Iv Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez John Marsh Iv to All <=- JM> I tried following the discussion on Tesla coils and even JM> downloaded a packet of messages someone created and I think I JM> came in to the conversation too late. I don't think so, but I posted out a ton of references, and I posted you personally to try to get an exact idea of how big a coil you want. JM> Could some one explain to me the exact building of a tesla JM> coil (like instructions), like I was stupid. I could walk you through this step by step, but I have done this before here. Everything is in my archives... Everything. You only need to pull up the references post I sent, get my address (posted), and send me a blank 1.44 floppy for the files, schematics, the whole kit and kaboodle.... JM> I know about electronics, but I havent ever built a tesla JM> coil and need some help, I know I need a HUGE capacitor, but JM> what else? Primary coil, secondary coil, capacitor, spark gap, power supply, and some type of RF choking circuit to protect the power supply. All of this is covered in excruciating detail in my archives, and is available at no cost. You don't even really need to mail if you call this board locally and download my TESLA?.ZIP file. ... If all else fails... Throw another Megavolt across it! Cindex Support BBS (314) 837-5422 Florissant, MO. (1:100/395.0) � Area: Electronics Echo 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-27-94 21:00 From: Richard Quick To: John Marsh Iv Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 60Hz Line In � � � � 읕컴훃UUUUUUU컴컴� 袴袴袴袴袴袴袴袴 X1 �UUUUUUUUUUUUUUUU� � � � � 賈� � � /// � U|| ||U RFC1 U|| ||U RFC2 U|| ||U U|| ||U � � � � 쳐컴컴횽 O컴컴컴� � G1 � � � 컨� � C1 컫� � � � � L2 � 픘UUUUUUU컴컴컴컴� 曹컴훃UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU컴컴쾡 T1 L1 X1 - 15,000VAC @ 60mA Neon Transformer RFC1&2 - Radio Frequency Wound Chokes G1 - Spark Gap C1 - 0.01uf @ 20,000V Capacitor HV Pulse discharging type L1 - Tesla Secondary Coil L2 - Tesla Primary Coil T1 - Discharge Terminal (Toriod preferred) Note that C1 and G1 can be reversed in this particular circuit. Typical spec for L2 would be 15 turns of 3/8" soft copper water pipe wound into a flat pancake spiral coil (like a vinyl phono record) with the first (inside) turn 7 inches in diameter, turns spaced at 1/4 of an inch. This coil may be slightly saucer shaped (angle of incline not over 30 degrees) for good coupling with the 450 kHz secondary coil I detailed earlier this week. All grounding specified in this diagram should be to a heavy, dedicated, RF ground. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-28-94 15:22 From: Richard Quick To: John Marsh Iv Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� I thought I would take a moment and forward some additional information from my archives. This post covers some aspects of RF choking on the feed lines to the Tesla Tank circuit. I will refer to vol. 13, #2, page 6 of the Tesla Coil Builders Association publication NEWS. I have reproduced the relevant circuit diagram... >from archives PC1 X1 RFC 1A RFC 2A 컴컴컴컴쩡컴컴커붚컴컴컴程程粘컴쩡컴쿤程程컴�> TO TESLA TANK 컨� )�( � 컫� )�( � � )�( O .픔컴� )�( .픔컴훟 SAFETY GAP � )�( O 컨� )�( � 컫� )�( � 컴컴컴컴좔컴컴켸봉컴컴컴UUUUU컴컨컴컴훃UUUU컴�> TO TESLA TANK PC2 RFC 1B RFC 2B "Radio Frequency Chokes RFC 1A and 1B are wound with about 70 turns on a 1" cylinder (PVC, plastic, etc.). RFC 2A and 2B are wound with around 20 turns on a similar form. The size of the wire is not critical as long as the wire is capable of carrying the rated current." "Protective Capacitors PC1 and PC2 are not critical and can be rated in the vicinity of .5 to 2 microfarads. Use a voltage rating as high as possible. The usual 400-600 volt capacitors will not withstand kickbacks for very long. I prefer capacitors with ratings of from 2500 to 5000 (or higher) volts" The above is quoted from the article, X1 is of course the high voltage step up transformer that supplies the Tesla Tank. I will note that this circuit is the bare minimum protection required, and that this is only adequate for small (6") coils running under 1.5 KVA. Even the author, Harry Goldman, admits that this RF protection circuit does not eliminate, but only reduces the RF and kickback problem. Note his statement that the low voltage line PC (Protective Capacitors) capacitors (PC1 & PC2) need a rating of 2500 volts or higher. These capacitors are across the 120 or 240 volt 60 cycle line!!!! Imagine what voltage spikes are appearing in the house or shop supply line if 400-600 protective capacitors are routinely failing. Obviously the problem needs some more attention. Please note the modifications to the above circuit in my recommended circuit below. �------� | | X1 RFC 1A 컴|컴컴컴|컴컴커붚컴컴컴쩡컴컴컴컫컴컴程程粘컴> TO TESLA TANK | | )�( � � | | )�( � � | | )�( BC1 컨� O | LF1 쳐�. )�( 컫� o컴�. SAFETY GAP | | )�( � O | | )�( � � | | )�( � � 컴|컴컴컴|컴컴켸봉컴컴컴좔컴컴컴컨컴컴훃UUUU컴�> TO TESLA TANK | | � RFC 1B �------� 賈� grnd LF1 is a commercial heavy duty line filter wired in reverse. Where current throughputs are high I use several in parallel. Quality commercial line filters employ iron powder chokes, as well as the "PC" capacitors of the circuit at the top of this post. The Line Filters I use also have RF choke coils in the ground path; the ground wire can be run reversed (it is neutral) and can be used to trap stray RF, preventing ground path contamination to the 60 cycle breaker box. I should note that I use a minimum of two independent grounds. The core of X1, and everything to the right of X1 in this diagram, is grounded separately to a heavy, dedicated, RF ground. This heavy RF ground is also used to ground the base of the Tesla secondary. Note that the core of X1 is grounded in this diagram, where the top diagram shows the core floating ungrounded. I believe this was an oversight of Mr. Goldman's. BC1 is a Bypass Capacitor. I use high voltage barium titanate doorknobs, with stacks of four or more in series. A typical rating for a single cap would be .003 microfarad @ 30 KVDC, and using four of these caps in series I get .0007 microfarads at 120 KVDC. Since the AC rating is about half the DC rating on these type capacitors, figure a series stack of four will withstand a kickback of 50-60 KVAC in this use. Where center tap ground type xfrmrs are used for X1 (such as neon sign cores) BC1 must be divided into two units, and the center of the stack must be grounded with the xfrmr core (see the arrange- ment of PC1 and PC2 in the top most diagram). Use no more than .0008 or so microfarads per side, as too large a bypass capaci- tance will create an oscillating current in the high voltage windings on your step up xfrmr that will cause the xfrmr to fail. RFC 1A and RFC 1B are about 15-20 turns (minimum) of insulated wire on a large iron powder core. I use 2" diameter iron powder toroids to wind these chokes. I have found that the RF and Kickback protection of the circuit using bypass capacitors and iron powder (as opposed to air core) RF chokes is much better than the simpler circuit recommended by Mr. Goldman. If you are running a small tabletop Tesla coil, then Mr. Goldman's circuit is probably all you need. But if you are running, or intend to run, more than 1.5 KVA out of your power supply; look carefully at the circuit I have outlined. Remember... Over 1.5 KVA and the kickbacks are sounding like high powered rifle shots at the safety gap. They will "light up your life" if not properly contained and grounded. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-28-94 17:32 From: Richard Quick To: John Marsh Iv Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� > TESLA Primary coils The primary coil is a low resistance, heavy coil, through which the currents produced by the pulse capacitance travel. In discussing primaries we need to cover the "skin effect". Both high voltage and high frequency currents exhibit a property called skin effect. Skin effect describes a situation where the current does not penetrate the conductor, but instead flows on the surface of the conductor. This effect is very pronounced in Tesla tank circuits where both high voltage and high frequency are componets of the capacitor pulse. Studies of the Tesla tank circuit current show that the RF current ringing through the tank has very little penetration of the tank circuit conductors. This should be reflected in the choice of the conductors used to wire the tank circuit, and to wind the primary coil. I have had very good luck with conductors that offer a lot of surface area, as opposed to a large solid cross section. The preferred material for winding primary coils is thin wall soft copper water pipe or refrigerator tubing, wide sheet copper strap, or heavy braided copper ground strap. These matrials offer a low RF impedance, high Q, and large radiating surface areas. For wiring the Tesla tank circuit, such areas as buss connectors to capacitors, tap leads, and spak gap connectors, any of the materials above may be used, but I prefer heavy DC transmission wire. The DC transmission wire (like battery cable or welding cable) offers flexibility and a high grade insulation which helps prevent breakdown. The cables and connections should be carefully examined for areas where Q can be gained. Sharp edges or points should be removed to prevent corona losses, connections should be tight to reduce impedance, and sharp turns should be eliminated to reduce "off axis" inductance. The tank circuit wiring should be as short and straight as possible. The primary coil itself should be wound on a high Q insulator. For a coil form or coil supports, high density poly, plexiglas, lexan, acrylic, or other high Q hard plastic is ideal. The primary coil should be large. I have seen lots of holdovers from the classic age of coil building who insist on 2-3 turn primaries and HUGE capacitors to achieve the proper frequency of operation in the tank circuit. This is wrong. A tank circuit with a small capacitor, and a large primary inductance, will reach down to the same frequencies of operation. A tank circuit of this design will use less power, and therefore require a smaller step up xfrmr. The capacitor will be smaller, which further reduces the cost of the system. A large primary coil offers a much greater surface area for radiation and distributed energy transfer to the secondary. It couples better with a properly designed secondary. Due to these design advantages, an equal or greater amount of power is actually delivered to the secondary, despite the much smaller capacitance and input power. Using a large primary will allow you to reduce the value of your capacitor and your input power by 50% or more (frequently much more) without a reduction in output. Primaries designed to be operated with 9-15 turns will obtain power processing energies that are at least 50% greater than 2-3 turn primaries, provided that the secondaries are constructed to take advantage of the design. Secondary coils with the aspect ratios and numbers of turns that I have recommended here before, work best with large primaries tapped at 9-15 turns. So to give some advice for those winding six inch coils: plan on winding a primary coil from a conductor material that I have listed above, and use a conductor length of around 75 feet. For a four inch coil use about 50 or sixty feet of conductor. Your primary should end up about as wide as, or wider, than your secondary is tall. This way the secondary will nest in the large primary. The field flux from the primary will couple the entire length of the secondary winding for a distributed, high efficiency, energy transfer. More energy can be forced into the secondary, with lower input power, and reduced chance of breakdown and loss. Primary coils take several forms depending on the type secondary used with them. Modern secondaries, with high inductance and low aspect ratios, need primaries that are flat pancakes, or "saucer" (rising upwards as the turns move out) shaped spirals. Because this design is so efficient in energy transfers, critical coupling coefficients are achieved without using the old fashion vertical helix type primary coil. When designing primary coils, it is generally a good idea to test a particular coil shape before committing to a time consuming and expensive permanent coil. This is especially true for those who have not had much experience with primary coils of different shapes and sizes. Some cheap low Q wire can be picked up and used to make a temporary primary coil for testing. I set the secondary up on an insulated platform equipped with a good ground, then wind the test primary. To achieve the desired shape I use tire tubes (to build up "saucers") plastic wedges, tape, etc. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-27-94 15:25 From: Richard Quick To: John Marsh Iv Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez John Marsh Iv to All <=- JM> I tried following the discussion on tesla coils and even JM> downloaded a packet of messages someone created and I think I JM> came in to the conversation too late. I don't think so, but I posted out a ton of references, and I posted you personally to try to get an exact idea of how big a coil you want. JM> Could some one explain to me the exact building of a tesla JM> coil (like instructions), like I was stupid. I could walk you through this step by step, but I have done this before here. Everything is in my archives... Everything. You only need to pull up the references post I sent, get my address (posted), and send me a blank 1.44 floppy for the files, schematics, the whole kit and kaboodle.... JM> I know about electronics, but I havent ever built a tesla JM> coil and need some help, I know I need a HUGE capacitor, but JM> what else? Primary coil, secondary coil, capacitor, spark gap, power supply, and some type of RF choking circuit to protect the power supply. All of this is covered in excruciating detail in my archives, and is available at no cost. You don't even really need to mail if you call this board locally and download my TESLA?.ZIP file. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07-27-94 21:00 From: Richard Quick To: John Marsh Iv Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 60Hz Line In � � � � 읕컴훃UUUUUUU컴컴� 袴袴袴袴袴袴袴袴 X1 �UUUUUUUUUUUUUUUU� � � � � 賈� � � /// � U|| ||U RFC1 U|| ||U RFC2 U|| ||U U|| ||U � � � � 쳐컴컴횽 O컴컴컴� � G1 � � � 컨� � C1 컫� � � � � L2 � 픘UUUUUUU컴컴컴컴� 曹컴훃UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU컴컴쾡 T1 L1 X1 - 15,000VAC @ 60mA Neon Transformer RFC1&2 - Radio Frequency Wound Chokes G1 - Spark Gap C1 - 0.01uf @ 20,000V Capacitor HV Pulse discharging type L1 - Tesla Secondary Coil L2 - Tesla Primary Coil T1 - Discharge Terminal (Toriod preferred) Note that C1 and G1 can be reversed in this particular circuit. Typical spec for L2 would be 15 turns of 3/8" soft copper water pipe wound into a flat pancake spiral coil (like a vinyl phono record) with the first (inside) turn 7 inches in diameter, turns spaced at 1/4 of an inch. This coil may be slightly saucer shaped (angle of incline not over 30 degrees) for good coupling with the 450 kHz secondary coil I detailed earlier this week. All grounding specified in this diagram should be to a heavy, dedicated, RF ground.