Date: 07-30-94 16:27 From: Don Kimberlin To: Richard Quick Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� ...Nice sketch: RQ> 60Hz Line In RQ> | | RQ> | | RQ> +----UUUUUUUU----+ RQ> ---------------- X1 RQ> +UUUUUUUUUUUUUUUU+ RQ> | | | RQ> | -+- | RQ> | /// | RQ> U|| ||U RQ> RFC1 U|| ||U RFC2 RQ> U|| ||U RQ> U|| ||U RQ> | | RQ> | | RQ> +------O O------+ RQ> | G1 | RQ> | | RQ> -+- | RQ> C1 -+- | RQ> | | RQ> | L2 | RQ> +UUUUUUUU--------+ RQ> =+---UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU-----T T1 RQ> L1 ...but where do you plug the microphone in? ! Origin: Borderline! BBS Concord,N.C. (704)792-9241 (1:379/37) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Date: 02 Aug 94 17:47:00 From: Richard Quick To: Don Kimberlin Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 -=> Sez Don Kimberlin to Richard Quick <=- DK> ...Nice sketch: DK> ...but where do you plug the microphone in? Human voice T1 \/  � 꼼컴쩡컴�<--Diaphram � L2 � � V �<--Valve 쳐컴컴컴�} � � � � � } 袴袴鳩솬뷔賽� � } Gas in^ � � } Gas out> � � } � A1 � } L1 C1 훤袴袴袴袴袴袴袴袴� >>>> } {컴캑쳐컴쩡컴 < HF Gas stream> � } { o � } { G1 o � } {컴컴컴컴좔컴 < HF 쳐컴컴컴�} � earth 拙� The "gas under pressure" microphone was placed in the circuit between the air capacity terminal (T1) and the ground. The modulated air stream would in turn modulate the arc at A1. L2 is the Tesla secondary, L1 is the primary coil, C1 is the primary capacitance, G1 refers to a high speed rotary break. The power supply for this particular circuit was a high frequency CW alternator. This was only the first of many successful voice modulation transmitting devices used by Tesla in Colorado Springs and noted in June of 1899 (he had multiplexing already patented). Before I would take time to diagram his carbon microphone transmitters and receivers I would suggest you see: COLORADO SPRINGS NOTES 1899-1900, Nickola Tesla, published by NOLIT, 1978 Beograd, Yugoslavia, pp34-36... 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-03-94 11:56 From: Dave Halliday To: John Marsh Iv Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� JM|I tried following the discussion on tesla coils and even |downloaded a packet of messages someone created and I think I |came in to the conversation too late. Could some one explain |to me the exact building of a tesla coil (like instructions), |like I was stupid. I know about electronics, but I haven't |ever built a tesla coil and need some help, I know I need a |HUGE capacitor, but what else? Hi John - actually the value of the capacitor is pretty small - it just has to be of a very very high working voltage - remember that you are putting several tens of thousands of volts through it... Basically, what you are building is a resonant step-up transformer. Your primary circuit consists of a high-voltage source ( greater than 10KV at about 30 Milliamps ) fed to your resonant circuit through a spark-gap. The spark-gap provides the intermittant interruption of the high-voltage source that allows the coil to oscillate at a much higher frequency than your incoming house current ( 300-600 KHZ as opposed to 60 Hz ). Your secondary coil is made to be resonant at the same high frequency and it has two features - an incredibly solid ground on the bottom end and some form of capacitive loading ( a ball or a torroid "hat" ) on the top end. For grounding, I am using three 10' long copper plumbing pipes stuck into my yard at 5 foot intervals. For the power I will be running, this will be a marginal ground! Anyway, re-read the posts, send $10 off to Richard Quick for his video ( very well worth it! ) and start building! TTYL - Dave (206) 528-1941 (1:343/210.0) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-04-94 11:36 From: Don Kimberlin To: Richard Quick Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> -=> Sez Don Kimberlin to Richard Quick <=- RQ> DK> ...Nice sketch: RQ> DK> ...but where do you plug the microphone in? RQ> Human voice T1 RQ> \/  RQ> | RQ> #---+---#<--Diaphram | L2 RQ> # | V #<--Valve +--------} RQ> # | | # | } RQ> ----+-+#|#### | } RQ>Gas in^ | | } RQ>Gas out> | | } RQ> | A1 | } L1 C1 RQ> +------------------ >>>> } {---++---+--- < HF RQ> Gas stream> | } { o RQ> | } { G1 o RQ> | } {--------+--- < HF RQ> +--------} RQ> | RQ> earth === RQ>The "gas under pressure" microphone was placed in the circuit RQ>between the air capacity terminal (T1) and the ground. The RQ>modulated air stream would in turn modulate the arc at A1. .... ...Sonofagun! Old (young) Tesla had it all! Interesting situation occurs when trying to modulate extremely low frequencies, however. Unless the ratio between the modulating (speech) and modulated (radio) sigs is more than about 1:10, a lot of problems with distorted speech occur. Still, if the technology had ever gotten to wide use, I'm sure he would have worked that out.... (704)792-9241 (1:379/37) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 07 Aug 94 22:31:52 From: Richard Quick To: Don Kimberlin Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> DK> ...Nice sketch: RQ> DK> ...but where do you plug the microphone in? Human voice T1 \/  � 꼼컴쩡컴�<--Diaphram � L2 � � V �<--Valve 쳐컴컴컴�} � � � � � } 袴袴鳩솬뷔賽� � } Gas in^ � � } Gas out> � � } � A1 � } L1 C1 훤袴袴袴袴袴袴袴袴� >>>> } {컴캑쳐컴쩡컴 < HF Gas stream> � } { o � } { G1 o � } {컴컴컴컴좔컴 < HF 쳐컴컴컴�} � earth 拙� RQ>The "gas under pressure" microphone was placed in the circuit RQ>between the air capacity terminal (T1) and the ground. The RQ>modulated air stream would in turn modulate the arc at A1. DK> .... DK> ...Sonofagun! Old (young) Tesla had it all! Interesting DK> situation occurs when trying to modulate extremely low DK> frequencies, however. Unless the ratio between the DK> modulating (speech) and modulated (radio) sigs is more than DK> about 1:10, a lot of problems with distorted speech occur. Tesla mentions this effect several times in the COLORADO SPRINGS NOTES, both in reference to the circuit above, and in the carbon microphone circuits. He stated that the oscillations of the coil and the break rate on the gap had to be very rapid to reduce this effect and produce the clearest speech at the receiver; so it appears to me at any rate, that he was not only very aware of this problem, but that he had gone far towards solving it. DK> Still, if the technology had ever gotten to wide use, I'm DK> sure he would have worked that out... I think it was worked out. So many people fail to realize that Tesla designed and constructed not random inventions, but entire working systems. By "working systems" I mean things like the commercialized polyphase system in use today (and unchanged since Tesla first handed the patents to Westinghouse machinists). Tesla stated all the way up to the time of his death in 1943 that his wireless system was far superior to any system in use. The example above is drawn from his experimental work of 1899 and prior, as are the carbon microphone systems I mentioned (and provided references for). What I find particularly impressive: his system required no sensitve detector (receiver - amplifier), and no external power supply, for a person to hear human voice at the receiving end (the transmitter being very powerful and efficient at delivering energy). Tesla showed us fully developed triode vacuum tubes in 1891 in his public lectures (drawings, photos, and lecture transcriptions of the tubes exist). He was asked during his pending court case in 1916 why such tubes were not employed by him in receiver/ amplifier circuits. He answered that in his "system" they were not required: that no amplification was. He was clearly quite familiar with the design, construction, and operation of these tubes before Deforest; but did no further study with them because the knowledge and use of these tubes were not required for voice transmission. Tesla frustrates me time and time again for what he clearly documented but refused to employ/patent in some application; others grabbed credit for much of what was his original work. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-07-94 14:30 From: Mark Logsdon To: Richard Quick Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> Quenching typically relies on one or more techniques. The RQ> most common method used is expending the arc out over a RQ> series of gaps. Gaps of this type are know as "series static RQ> gaps". "Static" in this use refers to the fact that the gap RQ> is not actively quenched. The plasma is formed in several RQ> locations, and the voltage at each gap is lowered as more RQ> electrodes are placed in series. Heat, hot ions, and voltage RQ> are distributed. As the tank circuit loses energy to the RQ> secondary coil, the voltage and current in the tank circuit, RQ> and likewise across the series of gaps, drops to the point RQ> where the arc is no longer self sustaining. The arc breaks, RQ> and the capacitors are allowed to recharge for the next RQ> pulse. Isn't this the technique employed on automotive ignition systems? I have found that there is the gap in the spark plug and a gap inside the ignition module. 317-882-5575, 882-4471 (1:231/875) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 09 Aug 94 20:47:59 From: Richard Quick To: Mark Logsdon Subj: Tesla Coils, gaps 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> Quenching typically relies on one or more techniques. The RQ> most common method used is expending the arc out over a RQ> series of gaps. Gaps of this type are know as "series static RQ> gaps". ML> Isn't this the technique employed on automotive ignition ML> systems? I have found that there is the gap in the spark ML> plug and a gap inside the ignition module. While automotive ignition systems do bear some relation to Tesla patented domain (the car distributor is a synchronous rotary spark gap) there is really no need to quench an automotive ignition. Automotive ignition circuits do not produce the high current pulses and the associated high temperature plasmas typical of the Tesla tank circuit - main system spark gap. Since the automotive ignitions are not producing high current pulses, nor high temperature plasmas; my guess would be that the rotary break (distributor rotor and cap), and the points/ sensor, are more than sufficient by themselves to regulate the timing and duration of the spark at the plug. The spark plug gap is designed to ignite the fuel/air mixture in the combustion chamber, a far cry from the gap function in a coil. It is difficult perhaps to truly relate to the Tesla spark gap, even on a very small coil, without having actually messed with one. The main system spark gap in a Tesla coil is required to handle peak powers of many killowatts (very small coil) and megawatt, even gigawatt peak powers in medium and large coils. The arc is very thick, bright blue/white in color, and UV rich. Even on a tabletop coil system, the plasma channel formed when the gap breaks down is going to be several millimeters in diameter. On moderately powered coils, say 1.5 killowatts of input power from a couple of 12 kv 60 ma neon sign xfrmrs, the plasma channel formed at the main system spark gap is about as thick as a pencil; this is not the quietly buzzing yellow/orange arc of a Jacob's Ladder... We are talking about a brilliant blue/ white arc like that of a steel cutting flame. I guess I could add here that unlike the soft squeeling of the oxy/steel cutting flame, the pulsing nature of the arc across the spark gap on even a moderate sized coil is loud enough to require hearing protection and/or muffled enclosures; enclosures and shielding being recommended anyway to prevent UV burns to the eyes and skin as well as to allow ducting/ventilation for ozone and NOx gasses. On larger coils the rotary gaps spray molten slag as they vaporize the tungsten electrodes and suntan your retnas... Can you understand the difference now? The typical automotive ignition gives a cold, thin and spindly (threadlike), violet colored spark at the gap. Ignition systems require no quenching. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-07-94 01:58 From: Alexander Schek To: All Subj: What is Tesla? 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� HI there ! I am new in electronics and I wonder what a "Tesla" is... any help ? (562) 204 8361 � (4:880/21) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 10 Aug 94 16:30:38 From: Richard Quick To: Alexander Schek Subj: Tesla? 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez Alexander Schek to All <=- AS> I am new in electronics and I wonder what a "Tesla" is... AS> any help ? Nickola Tesla was the Yugoslavian born American immigrant (Midnight July 9-10, 1856 - 10:30 PM January 7, 1943) whose inventions and patented domain include: Rotating magnetic field (alternating current induction motor), 60 cycle polyphase power generation and transmission system (modern power grid), radio (US Supreme court overturned Marconi & Co. patents in his favor 1943), waveguide, synchronous rotary spark gap (distributor), electron microscopy, RF transformers, inductive and base fed resonate structures (Tesla Coil, flyback transformer, wireless power transmission), co-inventor of X-Rays (Roentgen credited him), mechanical and electrical oscillators. The list goes on and on; the US Patent office issued him over 160 patents. The "Tesla" is a unit of magnetic flux density in the SI and mksa electromagnetic systems named after the great unsung inventor. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-06-94 17:00 From: Tim Knights To: Don Kimberlin Subj: Re: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 What the H@@@ is a Tesla coil? (1:2240/176) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 10 Aug 94 16:05:13 From: Richard Quick To: Tim Knights Subj: RE: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez Tim Knights to Don Kimberlin <=- TK> What the H@@@ is a Tesla coil? > Imported from Archives 12/06/93 JF> For those of us who are wanna bees, What's a tesla coil...? A Tesla Coil is an air core, RF resonate, transformer. It is a very efficient source of very high voltage RF energy. Basically you take a high voltage pulse discharging capacitor and connect it to a large heavy coil. The cap is charged with a high voltage power supply (neon sign xfrmr, potential xfrmr, or power distribution xfrmr run backwards). The circuit consisting of the cap and coil is excited by discharging the cap through a spark gap. This way current of hundreds of amps at thousands of volts are made to oscillate through the coil. Frequency of oscillation is dependant on the number of turns in the coil and the size of the cap. This is the basis of the Tesla Tank circuit. The secondary coil or "Tesla coil" is a hollow form wound with several hundred turns of wire in a single layer. This coil has a natural RF resonate frequency based primarily on the length of wire used in the winding. The tank circuit frequency is made to match the secondary natural frequency by tuning: changing the number of turns in the heavy primary coil or changing the value of the pulse discharging capacitor. When the tank circuit freq- uency is matched to the secondary frequency, and the coils are placed in close proximity, energy is exchanged and transformed. RF voltages in the megavolts can be achieved with very high efficiency. The tank circuit literally converts line current into a series of rapid pulse dicharges with peak powers typically in the megawatt range. A simple coil setup is capable of producing what to the eye are continous spark discharges several feet in length, or longer. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-08-94 15:56 From: Terry Smith To: Don Kimberlin Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> -+- | RQ> C1 -+- | RQ> | | RQ> | L2 | RQ> +UUUUUUUU--------+ RQ> =+---UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU-----T T1 RQ> L1 DK> ...but where do you plug the microphone in? Dunno, but doesn't T1 go to the late night announcer's seat? Terry (203)732-0575 BBS (1:141/1275) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-08-94 15:25 From: Terry Smith To: Richard Quick Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> PC1 X1 RFC 1A RFC 2A RQ> --------+------+|+------UUUUU---+----UUUUU---> TO TESLA TANK RQ> -+- )|( | RQ> -+- )|( | RQ> | )|( O RQ> .+---+ )|( .+----o SAFETY GAP RQ> | )|( O RQ> -+- )|( | RQ> -+- )|( | RQ> --------+------+|+------UUUUU---+-----UUUUU---> TO TESLA TANK RQ> PC2 RFC 1B RFC 2B RQ> "Protective Capacitors PC1 and PC2 are not critical and can RQ> be rated in the vicinity of .5 to 2 microfarads. Use a RQ> voltage One little point of safety, which should be pointed out to the folks with limited electronics safety knowledge, is that PC1 and PC2 would have to be NO HIGHER than 0.1 uFd, in order to meet a 5mA ground current leakage standard. The circuit and values of PC1 & PC2 shown above could be lethal if the building ground connection were marginal or missing. Obviously that would decrease filtering effectiveness. A 120 V isolation xfmr, or additional stages to add both filtering and safety related line isolation, as you later described, would be possible solutions ot that problem. BTW, I have seen foolish and inattentive engineering of power supplies for broadcast equipment from one reputable and fairly quality oriented manufacter, which caused 6 and 12 mA of ground leakage with power on and off, due to similar low cost but irresponsible RF filter cap size choices. RQ> rating as high as possible. The usual 400-600 volt RQ> capacitors will not withstand kickbacks for very long. I RQ> prefer capacitors with ratings of from 2500 to 5000 (or RQ> higher) volts" What are "the usual"? Orange drop or block type small leaded film or mica caps? I would think that current ratings (which would be related to ESR, and filter effectiveness) might be more important than voltage rating, so long as no less than 400-600 volt rated caps were used. At 450 kHz, the Xc of the range of caps we're discussing would be 0.1 to 3 ohms, which makes me wonder if "voltage rating" isn't being substituted for physically larger cap with higher thermal and current limits? Such overall higher rated caps should be more effective as RF filters due to the same lowered ESR which results from other design parameters being increased. Do you know if smaller cap failures are from voltage punch through, or if it's really from cooking due to a 3-5 amp repetitive surge current demand, which small inexpensive caps can't handle? BTW, I'll be Freq'ing your archive tonight. I'm curious about what resonant circuits you might have brewed. Thanks for making it available! Terry (203)732-0575 BBS (1:141/1275) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 11 Aug 94 17:01:49 From: Richard Quick To: Terry Smith Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� PC1 X1 RFC 1A RFC 2A 컴컴컴컴쩡컴컴커붚컴컴컴程程粘컴쩡컴쿤程程컴�> TO TESLA TANK 컨� )�( � 컫� )�( � � )�( O grn曹컴캑 )�( grnd曹컴컴o SAFETY GAP � )�( O 컨� )�( � 컫� )�( � 컴컴컴컴좔컴컴켸봉컴컴컴UUUUU컴컨컴컴훃UUUU컴�> TO TESLA TANK PC2 RFC 1B RFC 2B RQ> "Protective Capacitors PC1 and PC2 are not critical and can RQ> be rated in the vicinity of .5 to 2 microfarads." TS> ...PC1 and PC2 would have to be NO HIGHER than 0.1 uFd, in TS> order to meet a 5mA ground current leakage standard. The TS> circuit and values of PC1 & PC2 shown above could be lethal TS> if the building ground connection were marginal or missing. Good point, though yours is a worse case scenario. There were already several reasons why I did not like the circuit above, you just added another reason to the list. TS> Obviously that would decrease filtering effectiveness. A TS> 120 V isolation xfmr, or additional stages to add both TS> filtering and safety related line isolation, as you later TS> described, would be possible solutions ot that problem. My improvements on Harry's circuit above work pretty well, and I have always loved isolation xfrmrs as an additional safety/RF/ spike/surge measure. I am considering the addition of a pair of back to back pole pigs in my low voltage feed lines for just this purpose. RQ> "Use a voltage rating as high as possible. The usual RQ> 400-600 volt capacitors will not withstand kickbacks for RQ> very long. I prefer capacitors with ratings from 2500 to RQ> 5000 (or higher) volts" TS> What are "the usual"? Orange drop or block type small TS> leaded film or mica caps? Again, I am quoting Harry Goldman above, but generally speaking the "PC" caps used in Harry's circuit are the typical "can" type caps used in capacitive start motors. I have seen a lot of these used (and NO they are not filter caps) simply because they are cheap; surplus caps with a rating of .1 uf @ 400 vac are locally available for around $0.25... TS> I would think that current ratings (which would be related TS> to ESR, and filter effectiveness) might be more important TS> than voltage rating, so long as no less than 400-600 volt TS> rated caps were used. At 450 kHz, the Xc of the range of TS> caps we're discussing would be 0.1 to 3 ohms, which makes me TS> wonder if "voltage rating" isn't being substituted for TS> physically larger cap with higher thermal and current TS> limits? Very possible. TS> Such overall higher rated caps should be more effective as TS> RF filters due to the same lowered ESR which results from TS> other design parameters being increased. Good point. TS> Do you know if smaller cap failures are from voltage punch TS> through, or if it's really from cooking due to a 3-5 amp TS> repetitive surge current demand, which small inexpensive TS> caps can't handle? I don't know. You could ask Harry Goldman (I have posted his SNAIL address should you choose to correspond), as he recommended the above circuit (recently too); I have never used it. But in my experience voltage punch through has only occurred as a result of a typical coiling type "incident" where there was no doubt as to the cause (run away oscillator, direct strike to low voltage feed lines, xfrmr breakdown, etc..). Perhaps this is what he was referring to when he said the lower voltage caps don't last very long. On the other hand a repeated 3-5 amp surge current demand on the filter implies something else is wrong... perhaps he is not properly grounded or choke/filtered at the RF side of the xfmr??? Like I said... I don't know, but I would not recommend the above circuit. TS> BTW, I'll be Freq'ing your archive tonight. I'm curious TS> about what resonant circuits you might have brewed. Thanks TS> for making it available! Thank you for the intelligent and progressive input. The TESLA?.ZIP file is not as complete as I would like to see it, but I feel it is a worthwhile contribution. Please make it available locally after you grab it. Your input in this thread has been included in it's entirety in the file, and has been appreciated. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-11-94 22:24 From: Mark Logsdon To: Richard Quick Subj: Tesla Coils, Gaps 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> ML> systems? I have found that there is the gap in the spark RQ> ML> plug and a gap inside the ignition module. RQ> While automotive ignition systems do bear some relation to RQ> Tesla patented domain (the car distributor is a synchronous RQ> rotary spark gap) there is really no need to quench an RQ> automotive ignition. Automotive ignition circuits do not RQ> produce the high current pulses and the associated high RQ> temperature plasmas typical of the Tesla tank circuit - main RQ> system spark gap. OK, I confess: I was really speaking of gas turbine ignition systems, which are much higher in energy than that of an automobile. RQ> Can you understand the difference now? The typical automotive RQ> ignition gives a cold, thin and spindly (threadlike), violet RQ> colored spark at the gap. Ignition systems require no RQ> quenching. An automotive spark makes a "tick tick" sound, but a gas turbine igniter goes "snap snap." Maybe that would indicate a need for quenching. What do you think? 317-882-4471 (1:231/875) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 12 Aug 94 18:11:09 From: Richard Quick To: Mark Logsdon Subj: Tesla Coils, Gaps 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Mark was wondering if ignition systems required quenching... ML> I have found that there is the gap in the spark ML> plug and a gap inside the ignition module. RQ> While automotive ignition systems do bear some relation to RQ> Tesla patented domain,, there is really no need to quench an RQ> automotive ignition. Automotive ignition circuits do not RQ> produce the high current pulses and the associated high RQ> temperature plasmas typical of the Tesla spark gap. ML> OK, I confess: I was really speaking of gas turbine ML> ignition systems, which are much higher in energy than that ML> of an automobile. Much higher..... Humm..., how much is "much higher"? Are we talking an order of magnitude higher? Small tabletop Tesla coils have tank circuit currents that start around 9000 volts at 10 amps. That is a peak power of a measley 90,000 watts, or nearly 1/10th of a megawatt. RQ> Can you understand the difference now? The typical RQ> automotive ignition gives a cold, thin and spindly RQ> (threadlike), violet colored spark at the gap. Ignition RQ> systems require no quenching. ML> An automotive spark makes a "tick tick" sound, but a gas ML> turbine igniter goes "snap snap." Maybe that would indicate ML> a need for quenching. What do you think? I have no experience at all with turbine ignitions, but I do have some experience with automotive ignitions, oil burner ignitions, and gas ignitions (like a stove or furnace). In all of the electrical ignition systems I have seen, peak powers of 250 watts are considered high; more than enough to go "snap snap". On the other hand a commercial plasma cutter rated at 20,000 watts weighing around 250 lbs. with a three phase input (65 amp breaker on each phase), is still running peak powers 4.5 times smaller than a measley tabletop Tesla coil with a single 9000 volt 30 milliamp power supply (8 lbs, 270 watts). How you might wonder can I get away with such a statement and not get flamed here? Peak powers of 90,000 watts from a 270 watt neon sign xfmr???? More than four times the peak power delivered by the commercial three phase plasma cutter???? In Tesla coiling I stress the need for quality high voltage, plastic film, oil covered, pulse discharging capacitance. This is the key. Charged with a neon sign xfrmr or other high voltage power supply, it is pulse discharged to deliver these enormous peak powers. With a neon sign xfmr the capacitor value is usually set to fully charge in one half of a cycle: 60 cycle = 120 full charges (in one second) or ~120th of a second to cycle the capacitor once. The pulse discharge of this capacitor on the other hand only takes a few microseconds, thus the peak powers are amplified to enormous porportions without violating any conservation of energy (thermodynamics) laws. What controls this? The spark gap. It MUST quench in order to deliver these peak powers. A spark gap that does not quench will cause the arc at the gap to "hang"; peak powers (and tank circuit efficiency) drop off dramatically. At the same time a gap that quenches well makes it own work: the faster the quench time, the shorter the pulse duration, and the greater the peak power :|: the greater the peak power, the hotter the arc, the thicker the plasma channel, the more electrode abalation, the harder to quench (longer pulse duration)... Vicious cycle, Catch 22, whatever you want to call it. My example of peak power relationships grows to even enormous porportions if we increase the current and voltage input into the Tesla Tank circuit, and increase the capacitor size accordingly. My figures show that on my really "hot" tank circuit: primary coil = 100 foot length of 1/2" soft copper water pipe, capacitor size .05 uf (rated at 90 kvac pulse), input power = 20,000 volts @ .5 amp = 10,000 watts rms (half of the plasma cutter). The peak power at the spark gap easily exceeds 10 megawatts with a tank current of over 500 amps. Now I am running 50% of the input power of the commercial plasma cutter, but my peak powers as handled by the spark gap are rivaling what most communities draw... The difference is RMS power vs peak power; but at the spark gap in the Tesla Tank circuit it is a reality (and at the discharge terminal of the coil system as well). So are you telling me that the turbine ignition systems you are familiar with are running peak powers (or rms powers) over a few killowatts and require some arc quenching? Do you see any high voltage pulse rated capacitance used to amplify the peak powers in the ignition circuit to deliver a hotter arc? If not... there is no requirement to design a discharge or gap system to quench. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-11-94 17:03 From: Don Kimberlin To: Richard Quick Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> RQ> DK> ...Nice sketch: RQ> RQ> DK> ...but where do you plug the microphone in? RQ> Human voice T1 RQ> \/  RQ> | RQ> #---+---#<--Diaphram | L2 RQ> # | V #<--Valve +--------} RQ> # | | # | } RQ> ----+-+#|#### | } RQ>Gas in^ | | } RQ>Gas out> | | } RQ> | A1 | } L1 C1 RQ> +------------------ >>>> } {---++---+--- < HF RQ> Gas stream> | } { o RQ> | } { G1 o RQ> | } {--------+--- < HF RQ> +--------} RQ> | RQ> earth === RQ>The "gas under pressure" microphone was placed in the circuit RQ>between the air capacity terminal (T1) and the ground. The RQ>modulated air stream would in turn modulate the arc at A1. DK> .... DK> ...Sonofagun! Old (young) Tesla had it all! Interesting DK> situation occurs when trying to modulate extremely low DK> frequencies, however. Unless the ratio between the DK> modulating (speech) and modulated (radio) sigs is more than DK> about 1:10, a lot of problems with distorted speech occur. RQ>Tesla mentions this effect several times in the COLORADO RQ>SPRINGS NOTES, both in reference to the circuit above, and in RQ>the carbon microphone circuits. He stated that the oscil- RQ>lations of the coil and the break rate on the gap had to be RQ>very rapid to reduce this effect and produce the clearest RQ>speech at the receiver; so it appears to me at any rate, that RQ>he was not only very aware of this problem, but that he had RQ>gone far towards solving it. ... ...Seems like he ran up against the problem, then, and recognized it... [...] RQ>Tesla stated all the way up to the time of his death in 1943 RQ>that his wireless system was far superior to any system in RQ>use. The example above is drawn from his experimental work of RQ>1899 and prior, as are the carbon microphone systems I RQ>mentioned (and provided references for). ... ...My BIG question: What records exist describing his *speaking* on what could be called "radio waves?" The world credits Reginald Fessenden with it on December 24, 1906, and if I can correct that, I'd want to. RQ> What I find particularly impressive: RQ> his system required no sensitve detector (receiver - RQ> amplifier), and no external power supply, for a person to RQ> hear human voice at the receiving end (the transmitter being RQ> very powerful and efficient at delivering energy). RQ> Tesla showed us fully developed triode vacuum tubes in 1891 RQ> in his public lectures (drawings, photos, and lecture RQ> transcriptions of the tubes exist). He was asked during his RQ> pending court case in 1916 why such tubes were not employed RQ> by him in receiver/amplifier circuits. He answered that in RQ> his "system" they were not required: that no amplification RQ> was. He was clearly quite familiar with the design, RQ> construction, and operation of these tubes before Deforest; RQ> but did no further study with them because the knowledge and RQ> use of these tubes were not required for voice transmission. ...I'm not so certain that was a function as much of Tesla's technology as it would be that the waves Tesla produced are what we would call "low frequency radio." At that point in time, all the big old powerful hogs of spark and alternator transmitters on low frequency delivered very powerful signals. Before the world had more sensitive vacuum tubes, a range of far less sensitive detectors with names like "coherer" and such were used by everyone. It wasn't till after vacuum tubes came around that people discovered higher frequencies could also be made useful... they were actually considered useless until the 1920's...and it wasn't until the 1930's that "shortwave radio" really came into vogue...the "lowfers" were still in pretty wide use. In fact, a number are still there today, in several sorts of applications... RQ>Tesla frustrates me time and time again for what he clearly RQ>documented but refused to employ/patent in some application; RQ>others grabbed credit for much of what was his original work. ...There is no doubt about that. Any pointers you have to that first speech on electromagnetic waves by Tesla are appreciated! (704)792-9241 (1:379/37) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 16 Aug 94 11:09:34 From: Richard Quick To: Don Kimberlin Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� DK> ...My BIG question: What records exist describing his DK> *speaking* on what could be called "radio waves?" The world DK> credits Reginald Fessenden with it on December 24, 1906, and DK> if I can correct that, I'd want to. Tesla addressed the Franklin Institute in Philadelphia in February 1893, and the lecture was repeated to the National Electric Light Association in my hometown, St. Louis, in March 1893. The two lectures employed all of the equipment and elements of Tesla's radio patents. He operated a spark gap transmitter and wireless receiver. A large Geissler tube was substituted for the spark gap in the reciever circuit, and it glowed brightly when the transmitter was energized. To my knowledge this was the first time radio was publically demonstrated and all four of the key tuned circuits were discussed. RQ> Tesla showed us fully developed triode vacuum tubes in 1891 RQ> in his public lectures (drawings, photos, and lecture RQ> transcriptions of the tubes exist). He was asked during his RQ> pending court case in 1916 why such tubes were not employed RQ> by him in receiver/amplifier circuits. He answered that in RQ> his "system" they were not required: that no amplification RQ> was. DK> ...I'm not so certain that was a function as much of Tesla's DK> technology as it would be that the waves Tesla produced are DK> what we would call "low frequency radio." At that point in DK> time, all the big old powerful hogs of spark and alternator DK> transmitters on low frequency delivered very powerful DK> signals. Before the world had more sensitive vacuum tubes, DK> a range of far less sensitive detectors with names like DK> "coherer" and such were used by everyone. It wasn't till DK> after vacuum tubes came around that people discovered higher DK> frequencies could also be made useful... they were actually DK> considered useless until the 1920's...and it wasn't until DK> the 1930's that "shortwave radio" really came into vogue Good point, but I think I can also see another perspective. I am familiar with coherers and other "sensitive devices" used by early radio pioneers. The range limits of a damped wave transmitter and the poor quality receiving circuits drove many early spark gap xmitters to enormous peak powers to get out. Maj. Edwin H. Armstrong did most of the receiver work that brought higher frequencies into use, with his development of the regenerative (or feedback) amplifier circuit, and later the superhet "beat-note" circuit which forms the basis of most modern radio and radar reception. But this still does not account for Tesla's oft repeated statements that all such systems (from the early low freq spark xmitters - to modern high freq telcom) are inherently wasteful and inefficient. Tesla layed it on the line, saying that radio (regardless of freq) is highly inefficient when looking at the power broadcast vs. the power received. He stated that radio is only 10% efficient at best. He compared commercial radio transmission efficiencies to commercial electrical power transmission (over 90% efficient to the consumer/receiver). Yet another way: an omni-directional radio transmitter/antenna is like setting a candle or bulb on top of a tower. Energy is radiated all around. If you want to focus and direct the radiated energy, then the antenna can be modified... for a flame or a lamp you would put a parabolic refector behind it. But the laws of radiation mean that the strength of the signal drops off in a relation to the square of the distance. The energy is disbursed rapidly, and most of it is lost. To receive a tiny fraction of the signal at any distance requires some equipment: with the lamp or flame you would use a lens first, at longer distances you would use photon amplification. Radio relies on larger, more powerful and sophisticated, receivers and amplifiers. What is the efficiency of transmitting alternating currents through a wire compared to the efficiency of radiating systems? Tesla said that by conduction into the ground and upper atmosphere he could deliver not only intelligible signal, but useable power. He realized early on the inefficiency of radiated signal systems, and focused on a system that employed wireless conductors instead. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-12-94 21:37 From: Jonathan Luthje To: Alexander Schek Subj: What is Tesla? 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Gday Alexander, if you are referring to a Tesla coil, it is basically a device which pumps out a whole lot of voltage (via either a Walton-Cockcroft voltage multiplier, or a transforming coil in a tower (hence the name Tesla COIL)), and can make some interesting lightening fX. The ones i have seen range from a (small) 250kV up to a whopping 2.5MV (Mega-volts), the later of which reqiures a faraday sheild to keep it "in tow". . . . any other questions. . . .just direct them here! Cheers Jon, (13 lines) (3:640/215) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 16 Aug 94 12:12:10 From: Richard Quick To: Jonathan Luthje Subj: What is Tesla Coil? 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez Jonathan Luthje to Alexander Schek <=- JL> The ones i have seen range from a (small) 250kV up to a JL> whopping 2.5MV (Mega-volts), the later of which reqiures a JL> faraday sheild to keep it "in tow". . . . JL> any other questions. . . .just direct them here! Sure, what do you recommend as a good spark gap design for the Tesla Tank circuit? 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-12-94 23:30 From: Don Kimberlin To: Terry Smith Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� RQ> -+- | RQ> C1 -+- | RQ> | | RQ> | L2 | RQ> +UUUUUUUU--------+ RQ> =+---UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU-----T T1 RQ> L1 TS> DK> ...but where do you plug the microphone in? TS>Dunno, but doesn't T1 go to the late night announcer's seat? TS> ...Do you reckon even *that* would keep them awake? I can remember plenty of times at 3 AM when those flourescent lights just hurt my eyes so bad...I think I'll just close my eyes and rest them for a few mom....zzzzzzzzzz.... Oh, wow! What's that? Darn! No program audio alarm! Wow! look at that automation over there, all the tapes going thwup, thwup, thwup where they ran right out. Quick! Grab a music tape and get it onto one of those drives fast! (Happens every time!) (704)792-9241 (1:379/37) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-11-94 17:05 From: Don Kimberlin To: Richard Quick Subj: Re: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� TK>What the H@@@ is a Tesla coil? SET TESLA_QUESTION_DEFLECTION.SYS /on ...over to you, Richard Quick! ...We have the benefit of a real student of Tesla here in Richard, so let's let him give you that lecture! (704)792-9241 (1:379/37) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-15-94 13:28 From: Mark Logsdon To: Richard Quick Subj: Tesla Coils, Gaps 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� ML> OK, I confess: I was really speaking of gas turbine ML> ignition systems, which are much higher in energy than that ML> of an automobile. RQ> Much higher..... Humm..., how much is "much higher"? RQ> Are we talking an order of magnitude higher? A gas turbine has two things working against its starting: high pressure ratios, e.g., compression ratios around 15:1, and more importantly, extremely high air flow. It therefore requires a hot spark. The spark is measured in energy rather than power. A typical spark from a turbine ignition system is around three Joules of energy. RQ> So are you telling me that the turbine ignition systems you RQ> are familiar with are running peak powers (or rms powers) RQ> over a few killowatts and require some arc quenching? All I can say is that there is a spark gap in series with the igniter plug. 317-882-4471 (1:231/875) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 17 Aug 94 12:00:42 From: Richard Quick To: Mark Logsdon Subj: Tesla Coils, Gaps 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez Mark Logsdon to Richard Quick <=- ML> OK, I confess: I was really speaking of gas turbine ML> ignition systems, which are much higher in energy... RQ> Are we talking an order of magnitude higher? ML> A gas turbine has two things working against its starting: ML> high pressure ratios, e.g., compression ratios around 15:1, ML> and more importantly, extremely high air flow. It therefore ML> requires a hot spark.... ML> ...there is a spark gap in series with the igniter plug. Gotcha, and, being the curious type, I checked into this a bit more. It appears that the spark gap in the module is employed to achieve a higher voltage - higher energy (read hotter) spark at the igniter plug. If you saved the original post I sent on spark gap technology, you will see where I discussed, in addition to quenching, another aspect of gap design having to do with field shape vs. breakdown voltage. A single spark gap has a very strong electrostatic field between the gaps which builds as the voltage rises. By adding a second gap to the system this field strength is greatly reduced. #1) B+ 컴컴컴컴컴컴컴컴컴컴o o컴컴띱 grnd #2) B+ 컴컴컴훟 o컴컴컴컴컴o o컴컴띱 grnd In line section #1, with a single gap between the B+ and the ground, a very strong electrostatic field is established at the gap. This gap breaks down with a much lower voltage. To achieve performance, the gap must be set very wide; too wide for pratical use with a high energy igniter plug such as we are discussing. Line section #2 on the other hand, has an insulated section isolated between two gaps. This section has little or no voltage impressed upon it by the B+. The breakdown voltage of line section #2 is much higher than line section #1, EVEN IF THE TOTAL GAP DISTANCE IN LINE #1 IS AS MUCH AS EIGHT TIMES GREATER THAN LINE #2. That is your answer. It has nothing to do with quenching, it has everything to do with breakdown voltage. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-16-94 00:55 From: Andre Dault To: All Subj: Building a Capacitor 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Hello there people... All this talk of Tesla coils is right in time.. I'm in the middle of building a Telsa Lightning Generator (tesla coil) But I need some capacitors (big ones) I need .003 - .005 uF from 15,000 - 25,000 WVDC.. If anyone knows a combination of capacitors or how I could build one.... It would be greatly appreciated. Andre Dault (705) 969-5213 (1:224/90) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 21 Aug 94 19:55:41 From: Richard Quick To: Andre Dault Subj: Tesla coil, cap, 1/2 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez Andre Dault to All <=- AD> Hello there people... All this talk of Tesla coils is right AD> in time.. I'm in the middle of building a Telsa Lightning AD> Generator (tesla coil) But I need some capacitors (big ones) AD> I need .003 - .005 uF from 15,000 - 25,000 WVDC.. If anyone AD> knows a combination of capacitors or how I could build AD> one.... It would be greatly appreciated. ... OK, By Request... The High Voltage, Pulse Discharge, CAPACITOR, Many high voltage projects require a high voltage pulse discharge capacitor. Whether your project is a laser, Tesla coil, rail gun, high power taser, or particle accelerator, you will most likely need a high voltage rated pulse discharging capacitor in your device somewhere. Commercial units are expensive. Manufacturers of these units do not stock them. Each and every unit is built to order. "Off the shelf" units do not offer the performance required for most high voltage projects. Off the shelf capacitors get hot, have high loss to output ratios, and/or will break down in spark excited tank circuits. Some types are potential explosion hazards. You can build your own capacitors for these projects from polyethylene plastic and aluminum flashing. The following instructions are for a pulse discharging capacitor with a .02 uf at 35-40 kvdc rating. The unit is rated for work in spark excited tank circuits with up to 15 kvac rms inputs, 12 kvac is the recommended maximum rms voltage rating, and they will run all day pulse discharging 10 kvac without getting warm. This is an ideal unit for small Tesla coils, and may be run in series/ parallel combinations for Tesla coils from desktop size up to 4 kva megavolt coils. The material cost is around $100.00 per unit as opposed to $150 - $300 for a similar commercial capacitor. Materials for this unit are as follows: Three yards of low density, 60 mil, polyethylene plastic. One ten inch by twelve inch sheet of 1/4" plexiglas. One fifty foot roll of 14 inch wide aluminum flashing. Eighteen inches of 1 inch schedule 40 pvc pipe. Twenty inches of 6 inch PVC DRAIN PIPE. DO NOT USE SCHEDULE 40! One: six inch pvc DRAIN PIPE END CAP. Two: end caps for the 1 inch schedule 40 pvc pipe. The end caps must have flat bottoms (not rounded) or you will need to cut them. One gallon of pure U.S.P. Mineral Oil. Two: 1/4 x 20 brass machine screws and four nuts. Two: #8 Pan Head Machine screws with washers and nuts. Screws should be equal to or less than 3/8ths of an inch long. Loctite thread fastener (medium strength) Six or eight: 12" long nylon wire ties PVC cement (medium body, clear, works best) PrepSol (Dupont paint store) or U.S.P. alcohol Four inch stack or clean newspaper or BUTCHERS PAPER Lint free wipes or good quality paper towels. Don't use the cheap stuff. ----------------------------------------------------------------- BUILDING THE CAPACITOR TANK Start out by cutting the PVC drain cap in half. You want to cut a ring 1-1/2" high off of the end cap. The bottom of the end cap should be saved intact with a 1-1/2" high side wall. Lay the ring cut from the 6" PVC drain cap on the sheet of 1/4" plexi and scribe a circle. Cut the circle out and glue it to the ring with PVC cement. This forms the clear, see through, lid for the capacitor tank. When the PVC cement has dried, drill two holes through the plexi for terminals. The holes should be on opposite sides of the lid. A small hole is drilled dead center for venting. Cut some strips of plexiglas, 3/4" wide by 2" long, out of the scrap material. Glue one of the 1" PVC end caps to the inside center of the 6" PVC drain cap section. Glue at least four of the plexiglas strips around the 1" end cap. The strips are placed so that they are flush with the 1" PVC end cap. They should form a "star" pattern radiating out from the center to form a shelf, 3/4" high, for the capacitor roll to sit on. This shelf prevents the roll from resting on the very bottom of the tank, and allows cool oil to circulate. It is important that there is sufficient room between the edges of this shelf and the side wall of the 6" drain cap to allow the 20" section of 6" PVC drain pipe to seat all the way to the bottom of the end cap. When the end cap assembly is dried, glue and seat the 6" PVC drain pipe in place. Use plenty of PVC cement to prevent leaks. Once the end cap is firmly seated in the 6" PVC pipe, then cement the 18" length of 1" PVC pipe down into the center ring. This pipe saves oil, as well as providing a center post for the capacitor roll. Glue the second 1" PVC end cap onto the top of the 1" pipe to seal it. Let the PVC cement dry thoroughly, then wash the tank out with strong detergent, and allow to dry. This completes the capacitor tank construction. ----------------------------------------------------------------- THE CAPACITOR ROLL The capacitor roll is made from the polyethylene sheet and the aluminum flashing. It is important that all of these materials are absolutely clean and free from defects.Clean and vacuum up a work area large enough to lay all of your plates and dielectric out. If things are dusty you may want to mop. When the work area is clean; lay down fresh newspaper, or even better, butcher paper, over the entire work area. You will need a long, hard, smooth, flat surface to roll your capacitor up on. A clean, paper covered concrete floor works well, as does a couple of paper covered buffet or serving tables. ... Continued in next post 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 21 Aug 94 19:56:52 From: Richard Quick To: Andre Dault Subj: Tesla Coil, cap, 2/2 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� ... Continued from previous post Cut the poly sheet lengthwise into three equal strips. The standard material width for this sheet is 48 inches. You will get three 16" wide strips from the sheet, though only two strips will be required to make one capacitor roll. The strips must be washed and wiped on both sides with PrepSol or alcohol and lint free wipes or high quality paper towels. Then they must be wiped dry. Static may become a problem here, and the dielectric may collect dust. A ground strap run to a water pipe may be wired to a copper or brass brush. The plates and dielectric may be swiped lightly to ground out static, but do not scratch the material. Cut two lengths of aluminum flashing 102" long. The flashing must be six inches shorter than the polyethylene strips. The material is already two inches narrower. Use a good pair of heavy duty scissors to cut the aluminum. The strips of flashing (plates) must have the corners well rounded, and have all sharp edges smoothed. Trim the corners off with the scissors, then sand all edges you cut it #150 emery cloth. Drill a hole, 1/2" from one end of each flashing strip for the terminal mount. Inspect your plate. It should have no dents, sharp points, "ruffles" along the edges, etc. Many flaws can be carefully worked out. The aluminum capacitor plates must be washed and dried. Fill a five gallon bucket with very hot water and a good squirt of liquid detergent. Roll the plate up and "dip, swish, and swirl" until all the sanding grit, manufacturing oil, and dirt wash off. Rinse the plate well and stand it on its edges on clean newspaper until it is dried. Don't worry if the plates oxidize a little. Lay out your meticulously clean plates and dielectric sheets. Lay one strip of plastic dielectric down first. Then lay a plate on top and center it. The plate is centered so that there is a one inch border of dielectric plastic evenly along the long sides. Line up the end of the plate with the terminal hole flush (even) with one END of the plastic. The far end of the plate will be six inches short of flush with the bottom dielectric sheet. Lay a second sheet of plastic on top so that it is exactly lined up the bottom strip of plastic. Lay the last plate down on the stack and center it. The plate is centered so that there is a one inch border of dielectric plastic evenly on both of the long sides. Now, the first plate you laid will have the terminal end flush with one end of the bottom di- electric, it makes no difference which end; line up the second plate so that the terminal end is flush with the end of the second dielectric sheet, but it must be at the opposite end from the bottom plate terminal. Cut two 1" strips of aluminum flashing 14" long. Tape them together into a 1" strap. Round it and sand it. Then untape it and wipe or wash the strips. Reassemble and punch a hole in each end. One hole for a 1/4" or larger screw (tank terminal), the other for the #8 pan head machine screw (plate terminal). Using a #8 pan head machine screw, mount this strap into the terminal hole on the top plate. Use a flat washer, a tiny drop of loctite thread fastener, and then a nut. Snug the connection down firmly. This strap serves as a high current lead from the plate to the terminal mount on the capacitor lid. Make sure that it is the smooth pan head of the screw pressing into the plastic capacitor dielectric as the capacitor is rolled up; not the sharp screw shaft. Do not allow the sharp threaded end to press into the capacitor. It is a good idea to have a couple of spare patches of 60 or 30 mil plastic to place under the pressure points of the terminal connector screws. This will help prevent breakdown. Starting from the terminal end of the top plate on the stack, the end with the terminal strap already mounted, roll the capacitor up as tightly as possible. Make sure that the top plate does not curl around to touch back on itself on the first turn. A strip of extra plastic here can be helpful. If the first turn of the roll looks poor, then unroll, line everything up, and try again. When the capacitor is tightly rolled, do not loosen your grip. Have an assistant put two wire ties together and slip them over the roll. When the wire ties are cinched, you may loosen up. As you rolled the capacitor up, the first plate in the stack worked its way out of the roll a few inches. This plate should present you with a terminal hole to mount a second 1x14" strap of aluminum to complete the second high current lead. Mount the second lead, making sure the smooth screw head is against the capacitor, not the sharp threaded end. You will have one lead coming up from inside the roll, and the other coming up from the outside. Put at least three wire tie strips around the roll. Two 12" wire ties connected together will give enough circumference. Set the capacitor roll into the tank. Fill with one gallon of mineral oil. The roll must be covered by at least a quarter inch of oil to suppress corona and prevent flashover. Note that the oil soaks into the roll. The level will drop after filling, and may drop again after use. Check on it occasionally until the capacitor is fully broken in, a period of about six months. Connect the leads from the capacitor roll to the tank lid. For the tank lid terminals use at least 1/4 inch brass machine screws and tighten down well. The head of the machine screw should be inside the lid, the first nut on top will hold the connection tight, the second nut is removable for connection to your circuit. Do not seal or glue the lid in place. Do not apply the full rated voltage to these units until they have set for at least three days, and the oil has had a chance to soak in to the roll. It is best to start them out at about half voltage, or less, and run them for short periods for the first few days on a smaller coil. These units run on the ragged edge of their voltage ratings, yet they are quite serviceable. On larger coils it is best to put these units in series/parallel to back them up against kickback. Because the material width of the polyethylene is 48", you get three 16" strips of dielectric from cutting a length. You will have one strip left over. Because of this, it is perhaps better to plan on building at least two units at a time. This makes more efficient use of material, but more so for the use of time. Once a temporary "clean room" has been established it makes sense to use it to fullest advantage. The effort in building a first class cap is worth the extra time and expense to do it right. The unit will last longer, withstand more abuse, and give you more capacitance if it is well con- structed. Once this effort is expended, and the unit is in service, don't blow it. Rather than risk the investment you should build more caps, "backing up" your existing caps and increasing power by adding caps as you go. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 22 Aug 94 16:52:40 From: Richard Quick To: Andre Dault Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez Andre Dault to All <=- AD> Hello there people... All this talk of Tesla coils is right AD> in time.. I'm in the middle of building a Telsa Lightning AD> Generator (tesla coil) But I need some capacitors (big ones) AD> I need .003 - .005 uF from 15,000 - 25,000 WVDC.. If anyone AD> knows a combination of capacitors or how I could build AD> one.... It would be greatly appreciated. I hope you find the information I posted on construction of high- voltage pulse discharging capacitors helpful. Would you mind posting some additional information on your project? Could you post some specs on the secondary coil (dimensions, wire size, # of turns etc.). Where did you come up with the design/plans? Is this to be a spark gap tank circuit? (I assume yes because of your capacitor specifications). We would all appreciate hearing more about it, and if you need specific assistance with any aspect of this project please do not hesitate to ask, I have more than a few coils under my belt. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-19-94 23:50 From: Don Kimberlin To: Richard Quick Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� DK> ...My BIG question: What records exist describing his DK> *speaking* on what could be called "radio waves?" The world DK> credits Reginald Fessenden with it on December 24, 1906, and DK> if I can correct that, I'd want to. RQ>Tesla addressed the Franklin Institute in Philadelphia in RQ>February 1893, and the lecture was repeated to the National RQ>Electric Light Association in my hometown, St. Louis, in March RQ>1893. The two lectures employed all of the equipment and RQ>elements of Tesla's radio patents. .... ...Thanks for that point. We have a FAQ under continuous revision over in Fido's BROADCAST echo, and I'll sure make certain we don't understate Tesla's involvement in the development of what evolved into "radio." RQ>.... The range limits of a damped wave RQ>transmitter and the poor quality receiving circuits drove many RQ>early spark gap xmitters to enormous peak powers ... ...But, as you so often note, not the sort of peaks Tesla worked to achieve. I have several really old books here, in which the people of the spark transmitter era make much of the "decrement" of their "tuning," essentially the waveshape of their output. I note one mention of some form of regulation in which one's "decrement" was not to exceed a numeric value of 0.2, unless deliberately detuning in order to create intentional interference to transmit a distress call. Since I came along after the spark era, I never sat down to read with understanding what they were doing, however it seems they were approaching some of Tesla's notions. And, as we both know, what "radio" evolved into followed a path of sine wave generators in later years, with pulse generation becoming a byway... RQ>... Tesla laid it on the line, saying that radio RQ>(regardless of freq) is highly inefficient when looking at the RQ>power broadcast vs. the power received. He stated that radio RQ>is only 10% efficient at best. He compared commercial radio RQ>transmission efficiencies to commercial electrical power RQ>transmission (over 90% efficient to the consumer/receiver). ...No doubt about that, due to scattering in most applications, just to blanket an area with a signal. The amount of power received at any one receiver is an infinitesimal portion of that transmitted... RQ>What is the efficiency of transmitting alternating currents RQ>through a wire compared to the efficieny of radiating systems? RQ>Tesla said that by conduction into the ground and upper RQ>atmosphere he could deliver not only intelligible signal, but RQ>useable power. He realized early on the inefficiency of RQ>radiated signal systems, and focused on a system that employed RQ>wireless conductors instead. .... ...What "conductors?" I can see the earth, of course, as one conductor. There is a "waveguide theory" particularly applicable to low frequency radio, where essentially the earth and the ionosphere form the walls of a "waveguide" around the earth. Would those be the "conductors" Tesla was alluding to? (704)792-9241 (1:379/37.0) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 28 Aug 94 23:48:46 From: Richard Quick To: Don Kimberlin Subj: Tesla Coils 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� -=> Sez Don Kimberlin to Richard Quick <=- DK> ...Thanks for that point. We have a FAQ under continuous DK> revision over in Fido's BROADCAST echo, and I'll sure make DK> certain we don't understate Tesla's involvement in the DK> development of what evolved into "radio." Very kind, and accurate, of you! RQ>What is the efficiency of transmitting alternating currents RQ>through a wire compared to the efficieny of radiating RQ>systems? Tesla said that by conduction into the ground and RQ>upper atmosphere he could deliver not only intelligible RQ>signal, but useable power. He realized early on the RQ>inefficiency of radiated signal systems, and focused on a RQ>system that employed wireless conductors instead. .... DK> ...What "conductors?" I can see the earth, of course, as DK> one conductor. There is a "waveguide theory" particularly DK> applicable to low frequency radio, where essentially the DK> earth and the ionosphere form the walls of a "waveguide" DK> around the earth. Would those be the "conductors" Tesla was DK> alluding to? Yes, more or less. Tesla saw the earth as a good conductor when he tuned to specific earth resonate frequencies below 30,000 Hz. He stated he could detect natural electrical standing waves in the ground, and when he tuned his coils to these natural frequencies, he was able to increase the amplitude of these standing waves. This is the ground connection of his system. For the air terminal, Tesla opened an ionized and conductive channel to the stratosphere. I believe he used a combination of X-Rays and hard UV produced by his single terminal bulbs which were mounted on the air terminal of the transmitter station. The high-voltage RF current from the air terminal was passed by this conductive channel directly into the rarified upper atmosphere where it would conduct freely around the globe. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-18-94 10:42 From: Bruce Kingsbury To: Jonathan Luthje Subj: What is Tesla? 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� JL> if you are referring to a Tesla coil, it is basically JL> a device which pumps out a whole lot of voltage (via either JL> a Walton-Cockcroft voltage multiplier, or a transforming JL> coil in a tower (hence the name Tesla COIL)), and can make JL> some interesting lightening fX. You forgot to mention "at high frequency". DC or 60Hz at that kind of voltage behaves in a much less spectacular manner. JL> any other questions. . . .just direct them here! Any other questions would best be directed to Richard Quick, he seems to be quite an authority on the subject of Tesla coils and well informed on Tesla's life in general. _,,/| \o o' =_~_= 64-7 847-5513 * (3:774/1150) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 08-21-94 16:43 From: Stan Phillips To: Andre Dault Subj: Building a Capacitor 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� AD> I'm in the middle of building a Telsa Lightning Generator AD> (tesla coil) But I need some capacitors (big ones) I need AD> .003 - .005 uF from 15,000 - 25,000 WVDC. Television recievers use the Picture tube as the high voltage filter capacitor. A metal coating on the inside of the glass (alluminum) and graphite (Aquadag) on the outside. The actual capacitance depends on the size of the tube. While I have never seen them used just as a high voltage capacitor, there is no reason why an old picture tube could not be used this way and they do operate at 20-30 Kv. (1:229/15) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Date: 29 Aug 94 18:16:17 From: Richard Quick To: Bruce Kingsbury Subj: Tesla? 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� JL> if you are referring to a Tesla coil, it is basically JL> a device which pumps out a whole lot of voltage (via either JL> a Walton-Cockcroft voltage multiplier, or a transforming JL> coil in a tower (hence the name Tesla COIL)), and can make JL> some interesting lightening fX. BK| You forgot to mention "at high frequency". DC or 60Hz at that BK| kind of voltage behaves in a much less spectacular manner. JL> any other questions. . . .just direct them here! BK| Any other questions would best be directed to Richard Quick, BK| he seems to be quite an authority on the subject of Tesla BK| coils and well informed on Tesla's life in general. Thanks for the complement and the vote of confidence Bruce!