Date: 06-28-94 13:41 From: Dave Halliday To: Richard Quick Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Hi Richard Just dropping a note to let you know that I am still incredibly busy at the store but I plan to have the coil up and running in about a month or so. I finally broke down and hired another full-time person so I can go back to "normal" 8-10 hour days... sheesh... Also, I was wondering about the current regulation going into the pole pig - you are using an arc welder. I have several baseboard heaters and I was thinking of paralleling a couple of those - lossy but hey! The work on the controller is going well - I have not hooked it up to the variacs yet - it's still at the store but it works well. I had done some other projects using that CPU so I still had some development boards left. Anyway, I will keep you posted (206) 528-1941 (1:343/210) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 06-30-94 16:14 From: Richard Quick To: Terry Smith Subj: 10KVA Tesla Coil ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ -=> Sez Terry Smith to Richard Quick <=- TS> I've noticed you've taken pains to document several aspects TS> of your work well, and that made me curious if you've tested TS> other parameters which have either not been mentioned, or TS> which I've failed to notice discussed here. In arcing TS> resonant circuits, how closely does output track input? TS> (Input, I assume, is safer and easier to monitor directly?) Ooohh, I'd say you have to be a little more specific with this question before I could tender a reply. How closely does output "track" input? TS> Outside of commercial environments, few people are equipped TS> to monitor induced and radiated fields quanitatively. I was TS> hoping you'd know of such studies by someone, if not equipped TS> to measure that aspect of large coil operation yourself. TS> (Impress me... Are you?) Impress you? Please Terry, spare me. To answer your question... This work was done by Tesla 100 years ago, and without the "commercial environment" you refer to. Please get a copy of Tesla's COLORADO SPRING NOTES. TS> As to the 6.78 MHz or other ISM frequencies, I strongly TS> suspect that imitation lightning is inherently too wideband TS> to possibly be confined to such allocated legal spectrum. RQ> BTW, where did you come up with this frequency??? TS> 47CFR18.301 (FCC ISM Regs, where unlicensed signal TS> strengths are conditionally unlimitted) Doesn't everyone TS> have a copy on the bookshelf by their computer? As I thought, this is completely unrelated to Tesla coils. I rarely operate over 500 kHz. TS> If emmisions could be confined to a narrow bandwidth, the TS> need to suppress signal transmission could be made moot. Oh really, can I quote you on this? TS> ... control bandwidth... TS> ... regulate the effective frequency of an arc TS> Quite frankly, I'm amazed that megawatt surges haven't TS> caused neighbors problems. RQ> I am sorry to disappoint you. TS> I've noticed in other posts discussion of coils large enough TS> to need a 60x80x50 foot bonded steel structure to house but TS> suppress the output of some coils. Where??? You mean I missed it??? Or was I the one posting? TS> This would be beyond what's available to hobbiests TS> without unusual means... Most people don't build coils that require such enclosures; those that do are sufficiently advanced to see the need for one. TS> and I have noticed emphasis at times on avoiding the cost of TS> commercial vacuum or G type mica capacitors. Must I go through this again? These caps (mica, vacuum) are poor performers in these circuits, regardless of cost. Cheapy home built poly/oil caps perform much better... at half the cost. Salt water capacitors work nearly as well for no cost. Get it??? TS> If you've conducted the operations described here, and TS> suppressed both RF complaints and regulatory violations, I'm TS> impressed, rather than disappointed. And I tried so hard not to impress you... Sparking Tesla coils are poor broadcasters of RF energy. Damped waves just don't radiate well to start with, and most of the energy gets consumed in the discharge when coils are properly tuned for spark. Preventing spurious emissions on larger, more powerful coil systems, or systems operating as transmitters for experimental work, is as simple as enclosing the coil area in hardware cloth, aluminum foil, or other conductive material, and the grounding the enclosure. I was blessed with a work area that is earth or earth berm on five sides; the sixth side is metal faced and can be grounded simply and easily. Proper line filtering and grounding prevents the 60 cycle power lines from becomming antennas. Inside the coil area all kinds of interference; inductive, conductive, and radiated; can be significant. Outside the coil area, TV's, radios, cable, telephone, etc., show only the slightest sign of leakage (I am talking high powered or radiant operation, and very short distances). By the time you get 50 feet away there is no significant signal, certainly nothing to worry the FCC or any other regulatory body. As I have stated many times... I get complaints about the noise, but never about EMI. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 06-30-94 16:15 From: Richard Quick To: Brian Thurston Subj: TESLA ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ BT> Hi Richard: BT> A very concise and succinct statement of the events BT> concerning Tesla and his AC transmission systems. Thank you very much Brian. BT> My only additional fact is that Tesla died pennyless in BT> Canada still trying to develop his wireless energy BT> transmission system into a commercial product. OK, we agreed he died pennyless. But he did reside in New York, and was in the city by all accounts when he died. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-01-94 23:17 From: Richard Quick To: Dave Halliday Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ DH> Just dropping a note to let you know that I am still DH> incredibly busy... Yes I knew you were out there lurking, and figured you were overworking yourself. I hope you have been saving stuff. DH> I was wondering about the current regulation going into the DH> pole pig - you are using an arc welder. I have several DH> baseboard heaters and I was thinking of paralleling a couple DH> of those - lossy but hey! Well, there is no doubt that using pole pigs in experiments like this requires some hefty ballast. For those that have not been following this for over half a year, I will restate. A "pole pig" is one of those electric utility cans that sit on power poles. They are properly called power distribution transformers. On power poles they are typically used to step a high voltage line down for residential/commercial use. For use as high voltage power supplies they are be reversed. The cores on these type xfmrs are "shell" wound. They do not saturate, and they will dim an entire neighborhood unless they are externally current limited. I have used an arc welder in series with one leg of the 240 volt input on the xfmrs (when run for HV supplies) to limit current. In this use, the shunted core of the arc welder performs the function of a variable inductance which limits the current. The problem is that the large core of the arc welder must energize, and the control variacs must energize, before the shell wound core of the pig becomes energized. We are talking a few hundred pounds of iron core and copper wire here. The resulting inductive delay is real, and it takes a second or two for the current flow to stabilize through the control circuits. This may not seem like a problem, but it is like driving a strange car with gross oversteer. Learning to handle the controls smoothly can be a bit nerve wracking at first. Another common method used to current limit pole pigs is resis- tive ballast. Paralleled high load resistance is added and subtracted to one or both legs of the low voltage supply. Oven elements, electric heaters, bulbs, and even containers of water doped with a couple teaspoons of baking soda, have been used for resistive ballast. The problem with these are two fold; things get very hot in a hurry (which is really no problem in winter, but in a garage in August...), and there is a greater voltage drop across the primary in the pig than is typical of purely inductive ballast. The advantage: the power supply limited with resistive ballast is smooth as silk; no inductive delay, the power comes up surely and slowly, no tugging on the variacs, and no sparking on the variac brushes. In practice, I have found that the best techinque is to split the ballasting up, using both resistive and inductive ballast in series. This gives the best of both worlds. DH> The work on the controller is going well - I have not hooked DH> it up to the variacs yet - it's still at the store but it DH> works well. Anyway, I will keep you posted Sounds great! ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 06-30-94 16:18 From: Richard Quick To: Michaelj Scott Subj: TESLA COILS, VIDEO ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ RQ>Thanks for the nice letter. Your video tape was posted this RQ>morning,you should receive it shortly after you get this post. MS> I've only had time to watch it once,... MS> the video does a great job of getting the thrill of MS> seeing a monster Tesla coil venting angrily at the MS> world. The sound effects were something of a surprise. We MS> loved watching the experiments progress... lets us get a MS> sense of the enormity of the project and the attention to MS> detail. MS> As I mentioned, I'll likely not be building a MS> Tesla coil, but the pictures to go along with this lively MS> reading are a must have for anyone who has been following MS> the Tesla coil threads. >If you have any problems, questions, comments, corrections, etc MS> As a mere electronic engineer, I don't think that I'm MS> qualified to offer any corrections to the high powered MS> lash-ups that you have concocted. MS> I look forward to sharing this with my co-workers. We need MS> to get a TV and VCR up to work, since I do not want this MS> tape to get "borrowed" like other lost tapes. Thank you very much for the complements. I am very glad you enjoyed viewing my work. MS> I was concerned that you or an onlooker might be hurt by an MS> errant spark. Sparks as big around as a beer can... We have an excellent safety record. Gary has been "tickled" only once by a static charge left on a capacitor, and I have never received even the slightest shock. I will get lots of posts from others who have seen the video, and they will say that my first shock at these power levels will be my last. But I am one of those people who seem to be very poor conductors. I wire safely, ground properly, and steer clear of the live 60 cycle. MS> Thanks for the wonderful video tape. It's the best thing MS> I've seen on the TV in quite a while... Thanks again for the excellent review, and enjoy the video in the comfort and safety of your living room. I was not kidding when I included the disclaimer in the video offer; all of the equipment ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 06-30-94 10:59 From: Don Kimberlin To: Richard Quick Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ RQ> DK> ...OK, that sounds like there is concern for somehow RQ> DK> "shaping" the induction field around a core, rather than RQ> DK> merely letting it assume some random proportions, and RQ> DK> attempting to couple to it. Or am I zooming off on a RQ> DK> tangent? RQ>No your shooting dead bullseyes. Field shaping is done RQ>primarily by altering the coil geometries. Both primary and RQ>secondary coils are juggled until good inductive coupling is RQ>secured. The formation of a small compact field; even in RQ>intensity and sweeping the secondary winding from the bottom RQ>turn to the top; usually allows the most efficient transfer of RQ>energy between two coils. ...Sure sounds like being concerned with the shape of the field being coupled to this Dumb Old Country Boy... RQ>... Then talking about... DK> ... the first "radio" people.. [...] RQ> DK> ...Now, THAT's interesting to me! So Marconi hung around RQ> DK> Tesla, eh? All the histories I've read seem to make no RQ> DK> mention of any connection between them. [...] RQ>How about US legal history. The United States Supreme Court RQ>overturned Marconi & Co. radio patents in 1943 after testimony RQ>and US Patent Office records showed clear priorities. It was RQ>proven that Marconi had had access to Tesla's early work and RQ>then went on to commercialization with that information. ...I recall Marconi claiming a "breakthrough" in his placing of a resonant circuit in the antenna. Thanks for opening up how Tesla really showed that to him... RQ>... talking about grounds as a... DK> ...low-reactance DK> interface to earth. RQ> RQ>Tesla was the first to apply ground to a tuned circuit... [...] RQ> DK> concept that the earth does not have unlimited RQ> DK> ability to conduct electricity away from a point contact. RQ> DK> Oh, electric power engineers know this, but the general RQ> DK> public.. RQ>What about earth resonate (electrically conducted) RQ>frequencies? ...Does this get off into the area of Tesla determining the resonant frequencies of the planet? Does the 50/60 Hertz power frequencies figure into this? I mean, since a wavelength at 50/60 Hertz is thousands of miles, it seems one could perhaps determine such existed...and then, I guess, from what you are saying, treat it as a huge "tuned tank." The mind boggles at what might happen if Man could induce enough in there to make significant circulating currents happen...visions of melting iron ore veins and such...volcanoes erupting and all at the utter extreme... RQ>... talking about Tesla's extra coil... RQ> RQ>The third coil is not inductively coupled to the primary/ RQ> RQ>secondary... uncoupled resonator which is base RQ> RQ>fed by transmission line.... is allowed to resonate RQ> RQ>freely, unrestricted by the inductive coupling between RQ> RQ>primary and secondary... I believe three coil designs are RQ> RQ>possible that are as high as 95% efficient. RQ> DK> ...Sure seems like that would have an effective use in RQ> DK> radio transmitters. Ever hear of anyone doing it there? RQ> DK> They do work to achieve the highest energy transfer, but RQ> DK> to my experience, only with a single primary and RQ> DK> secondary.... RQ>You would have to talk to a radio engineer, but the principal RQ>of resonance was discovered by Tesla. Tesla believed that RQ>large resonate transformers offered the key to worldwide RQ>xmission of commercial scale electrical power without wires. ...Well, power distribution transformers are, to my experience, "tuned" a bit to 50/60 Hertz - at least large ones. We once had to use one for the modulation transformer in an AM broadcast transmitter, and its resonant peak at 60 Hertz caused us fits till we shaped the audio passband coming in to attenuate the daylights out of stuff below 100 Hertz... RQ>If you electrically examine the system output, the secondary RQ>(or "driver") coil in the three coil magnifier is simply the RQ>secondary on a resonate transformer. The extra coil and earth RQ>(the top and bottom connections to the secondary driver coil) RQ>are acting as end resonators. Tesla to his patent attorneys RQ>clearly stated he had discovered, and operated his equipment RQ>modulated to, earth resonate frequencies below 30,000 Hz. ...Again, appears he determined some fundamental resonant frequency of the globe, and its harmonics... RQ>Looking at the oscillator as a whole, the current flow from RQ>the air terminal was small. Tesla operated at very high RQ>voltage, but retarded spark breakout when working with CW RQ>xmitters. The system is very easily converted to spark RQ>production, as witnessed by the publicity spark photos Tesla RQ>took of the Colorado Springs Machine. ...Heheheh....He sure was into Extra High Voltage, I guess. Now, a century later, we have people arguing deeply about the static fields around those, too. Could be scary. I note some claims that the right-of-way under those seems to not have land clearing problems with brush growing back, and that there are standards for farmers keeping cattle from grazing beneath them...something about souring milk and such. Don't know how much reality there is to all that.... (704)792-9241 (1:379/37) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-01-94 From: Michaelj Scott To: Richard Quick Subj: TESLA COILS, VIDEO ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ RQ>Thanks for the nice letter. Your video tape was posted this RQ>morning, you should receive it shortly after you get this RQ>post. I included a disk with many related text files. It RQ>should make for some interesting reading, as the archived RQ>material goes back over six months. Richard, I still haven't looked at the disk, but the tape has been seen by most of the engineers in the office. One who saw it dropped a brochure on my desk today for an auction Jul 14 in Dunkirk, NY. It seems that Ferranti Packard ( a RollsRoyce transformer company ) is being liquidated by Corporate Assets Inc (416) 962-9600 in Canada. What struck my eye was a setup with two Tesla coils with toroid top hats. This setup is called a Hipotronics model DIMS-5D B.I.L. tester consisting of impulse generator, 6 capacitors, 6 sets of spheres, 2 voltage divider stands, a computerized control station, and several spares that was all new in 1991. Also shown is a corona tester, a noise meter, FP spark gap station with adjustable 25 cm spheres, FP Transformer test system, 500 KVA with built-in 80Kv hipot coil which is supplied by Canron 500KVA 150kw motor generator or Superior Electric 190 KVA power stat. The Tesla coils are a matched pair and appear to be too tall (over 6 feet) to roll through a door. The Toroids appear to be 2 feet in diameter. The pictures show 6 inch copper braiding connecting everything together. The spark gap station has two electrodes ala stalctites and stalagmites with a gap of about 2 feet. Everything is extremely heavy duty on casters. The pictures show the control station in a separate room where it might be a bit safer. There are 9 pages of color photographs of low frequency coil winders, oil & silicon processing plants, ovens, pumps, machine shop stuff, and tons of copper & aluminum inventory. Delrin tubing, radiators, lightning arrestors, wire bushings, solenoids, contactors, and finished products from Ferranti-Packard like a 3600KVA auto transformer and a 1000 KVA 23695Y/216Y/125W. I'll make a copy and send you the original. It would make a great video. If this stuff has more than scrap value, it would be a shame to see it melted down before a hobbyist got a chance at it. Maybe some of the Tesla society people in the Buffalo area should be advised of the auction. (916) 448-2483 (1:203/52) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-01-94 09:42 From: Mike Procospo To: All Subj: Telsa Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ I'm interested in making a telsa coil for a little experiment of mine, could any of you write to me with some information on how I would go about doing this? Thankz a lot (407)323-0025 (1:363/77) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 06-28-94 21:44 From: Roy J. Tellason To: Roger Ream Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ 24 Jun 94, Roger Ream writes to Roy J. Tellason: RR> Actually, the article in Popular Electronics (and yes, it RR> was the mid-sixties, and I may be able to dig it up, if my RR> dad hasn't gotten rid of them) '64 or '65 feel about right, though I really couldn't say for sure. RR> was part of a two-parter, although PE didn't know it at the RR> time. The article concerning the "standard" tesla coil RR> spawned a tube-excited version called the "Li'l TC." I remember that one a little bit, used a horizontal output tube of some sort, didn't it? RR> I'll have to ask my dad if he still has the old box of PE, RR> next time I'm at the ol' homestead! I'll be looking forward to whatever you may find out. TANSTAAFL BBS (1:270/615) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-04-94 14:43 From: Richard Quick To: Mike Procospo Subj: Tesla Coil,cap,1/2 ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ The High Voltage, Pulse Discharge CAPACITOR Many high voltage projects require high voltage pulse discharge capacitors (cap). Whether your project is a rail gun, Tesla coil, or particle accelerator, maybe even a pulse laser or high powered taser, you will need some high voltage rated pulse discharging capacitor in your device somewhere. Plastic film caps are best. Commercial units are expensive. Manufacturers of these units do not stock them typically, every unit is built to order. Off the shelf caps (mica, vacuum, titonates) do not offer the performance required for many high voltage projects. Off the shelf capacitors get hot, have high loss to output ratios, and will break down in spark excited or high current tank circuits. Some types are a potential explosion hazard. You can build your own "plastic film" type 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 kv rms inputs, 12 kv is the recommended maximum rms AC voltage rating; but these caps will fire all day at 10 kvac without getting warm. This is an ideal unit for small to medium Tesla coils. The material cost is around $100.00 per unit as opposed to $200 - $250 for a custom commercial capacitor with this rating. Materials for this unit are as follows: Three yards of low density, 60 mil, polyethylene plastic. This plastic is available from any good sized plastics dealer. Dielec- tric constant between 2 and 2.2 (figure 2.0 in homemade caps). Dielectric strength is 1000 VDC per mil. (thousandth inch, USA) One ten inch by twelve inch sheet of 1/4" plexiglas. One fifty foot roll of 14 inch wide aluminum flashing. This will make 4.5 capacitors. Hardware store. Eighteen inches of 1 inch schedule 40 pvc pipe (thick wall). Plumbing supply 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 or flatten them. Plumbing Supply Twenty inches of CLEAN, 6 inch PVC DRAIN PIPE. DO NOT USE SCHEDULE 40! Six inch pvc, thin wall, DRAIN PIPE is available at any good plumbing supply in ten foot lengths. One: six inch pvc DRAIN PIPE END CAP. Plumbing supply One gallon of pure U.S.P. Mineral Oil. Drug Store Misc, items. Two: 1/4 x 20 brass machine screws and four nuts. Two: #8 Pan Head Machine screws with washers and nuts. Screws should be about 3/8ths of an inch or less 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 of 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 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 center (inside) of the 6" PVC drain cap. 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 and 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 oil to circulate. It is important that there is sufficient room between the edges of the 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 entire assembly dry thoroughly. Clean the tank out well. And 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 these materials are absolutely clean and free from defects. 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 tables. 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 dielectric, 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 for the second 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. When coiling in general it is best to "back up" this capacitance by placing two tanks in series and then placing two series sets in parallel. Thus you need four tanks to equal the value of one tank alone, but the four tanks will withstand twice the voltage. You will find it more economical to build three extra tanks, and run them in series/parallel, than building one tank and having to repair or replace it if it fails before it completes the long 6 month full break in period. Later you can risk the option of running them at their full rated voltage, should you choose, or increase power by playing it safe and building more caps. 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 constructed. 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 with additional caps as you go. Don't overdrive these, you will blow them. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-04-94 14:00 From: Richard Quick To: Mike Procospo Subj: Tesla Coil,xfmr,1/2 ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ > From archives ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 11-05-93 From: Richard Quick To: All Subj: 10KVA Tesla Coil ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ If you are interested in making a high voltage, high current, power supply, I can tell you how to do it for free.... First call the local neon shop(s) and tell them that your working with Tesla coils. Ask them to hold all of their failed xfrmrs so you can pick them up. Make sure you talk to the boss or foreman, and tell them that you want dead units. I have never had a shop turn me down for free cores. They are happy to get rid of them. There are two types of failed neon xfrmrs: warranty units, and old junk. The local shop must return units that fail within the two year warranty period back to the distributor for credit. Old junk (older than two years) you can pick up for free right from the local shop, but I also scavenge from the distributor. Ask where the failed warranty units go. If you can locate the distributor who sells wholesale, and handles failed warranty units, you have found a gold mine of high voltage xfrmrs. The distributor removes the PLATE from the xfrmr for return to the manufacturer, and throws the unit away. The manufacturer credits the distributor for the plate, as the shipping is too expensive. The cores go to the dumpster. After locating your source of failed units, be selective. Try to bring home the high current units. Ratings commonly used are 9 kv, 12 kv, & 15 kv, with common current ratings of 30 & 60 ma. Once in awhile you will come across a 120 ma unit. I grab all of the high current units (60 ma+) I can get in these voltages. First test your units. Use wire with a 15 kv rating or better. This wire can be obtained where you pick up the transformers. If you ask they will usually cut you off a few feet for free. I prefer using the solid polyethylene core from RG-213 coax, as it will withstand the voltage with gobs of extra safety margin. Draw an arc from the HV bushing to the case, one at a time. About 50% of the "failed" units I pick up are just fine and need nothing other than a clean up. There is nothing wrong with them. Often shops get these units from signs they have dismantled, and they just toss them into the junk pile with the rest. The other 50% are bad. Either one, or both, of the HV windings have broken down. These units can frequently be repaired. Remove all hardware, and insulators if possible. Take a hammer and a chisel and remove the cases by splitting them down the corners. Break off any stubborn insulators, but preserve the lead wires. You are left with a block of tar. Set the unit outside when it is very cold, or place in a freezer, and let it freeze solid overnite. The next morning, short the high voltage lead wires (you preserved them!)with a clip lead, and connect 110 volts across the primary. Since the cores on these transformers are shunted, they may be shorted without harm or blowing fuses. Let the unit cook for 15-30 minutes (varies with size & temp). Disconnect your leads, and with the chisel and hammer, chip a groove around the block. You want to score a groove lengthwise that will allow the block to cleave in two. Then, starting from one end of the block, chip until you hit the core, then do the same with the other end. Pry and chip the tar away from the core until the xfrmr is free. The core may then be disassembled, and the windings removed and examined. Kerosene and a stiff brush will clean up the windings and core of any remaining tar. The "cold-cook" method is fast and it works well. Frozen tar chips away cleanly. The "cooking" warms the core, softening the tar, and allowing it to release. The only other ways I know to free the cores are long soaks in solvent such as kero or gas, (the nasty waste does make a good tar crack filler), or melting out the tar with external heat from a fire or oven. Most units fail when the high voltage breaks down the tar insul- ation. The resulting carbon track shorts the winding. Simply removing the tar brings them back to life. Other times the coils break down internally. In this case I discard the winding after disassembling the core, and replace it with a good winding from another unit of the same model with the same type failure. While the core is apart, you can beef up the current output by removing a few of the shunting plates between the windings. Never take out more than 2 or 3 of these plates per side, as the additional power output will burn out the secondaries. Generally I get about 70-75 ma out of 60 ma units after I have finished. Rebuilt units need a little protection from the high voltage secondary outputs. The first thing I do is solder on a new lead wire to the high voltage windings. The HV secondaries are wound with very fine magnet wire, in the 30 ma units the wire is not much thicker than a coarse hair. Once a good solder connection is made, bed the connection and the first 1/2 inch or so of lead wire to the top of the HV winding with hot glue or clear epoxy. The lead wire need not be anything special, any thin insulated stranded wire may be used. Heavy wire increases the chances of a failed connection due to mechanical stress. When setting the unit up to fire you simply have to route it on insulators. The windings themselves are wedged against the core to prevent vibration. I have seen wood, bakelite, and plastic wedges used commercially. What I like to do is to soften up some 30 mil polyethylene plastic sheet in boiling water, and heat the core in a warm oven. I wrap dry softened plastic around the core and gently force the windings down on it. Once cooled, the windings have some insulation from the core, and they will not vibrate. The base wire from the HV windings must be grounded to the core. Use the original grounding point if possible, if not you may split the core apart slightly with a thin blade and insert the wire into the gap before you clamp the core back up. If required you may splice on a small piece of wire for added length. Neon sign transformers that have been rebuilt may be fired dry. The tar used to pot the cores for neon use does not really insulate well against the RF and kickback from the Tesla Tank. The units last longer when they are freed of the tar potting. The only other choice is to sink rebuilt units in mineral or xfrmr oil which is a very good RF insulator. I choose to fire them "dry"; it works, and there is no mess. Neons may be run in parallel to deliver the current required to fire medium sized coils, and I have run up to 4000 watts with banked neon power supplies. The general practice is to run these banks off of 240 volt feeds controlled through a variac. Neons with matched outputs are run in pairs in these banks. The primaries are paired up in series, and the secondaries are all paralleled to the HV buss. Phasing is important here, and each transformer must be checked as it is added to the bank to ensure it is in phase with the other units. If an xfrmr draws an arc from a lead wire brought to the HV buss, the primary or secondary connections must be reversed. Neons typically have an efficiency of about 50%, in that they draw twice as much power as they put out. This problem can be resolved with the use of power factor correction (pfc) capaci- tance across the line. The pfc capacitors used are the same as for alternating current motors. The voltage rating should be at least twice the line current used, and I like a 4x voltage margin for long life. The formula used to determine ballpark pfc is as follows: 9 10^ C = Corrected kVA ------ 2 2(pi)f e^ This should read C = Corrected kVA times (10 to the ninth power) over, (2 pi times f times e squared) C = required capacitance in microfarads f = frequency of applied voltage e = applied voltage Corrected kVA is determined by dividing the volt*amps (watts) output of the neon sign xfrmr by 1000 Using a pair of rebuilt 12 kv, 60 ma neons, with 2 shunting plates removed from the core next to each HV winding, and power factor correction capacitance, you can get a nice 1.5 KVA Tesla power supply with over 90% efficiency. Total cost: $5.00 for the pfc capacitors, and a few hours of time. I have unpotted dozens of neon transformers from many different manufacturers. I have tried to make this as informative as possible, and have checked it over for mistakes. If I have erred, or was not clear on something, please let me know. Use common sense, and don't expect the first attempt to work out. On my first attempt I managed to destroy a HV winding during the unpotting, as I did not know where the windings were located on the core. But once you see one core unpotted, with minor differences, you have seen them all. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-01-94 23:01 From: Richard Quick To: Don Kimberlin Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ We were talking about the conductivity of earth grounds... RQ>What about earth resonate (electrically conducted) RQ>frequencies? DK> ...Does this get off into the area of Tesla determining the DK> resonant frequencies of the planet? Does the 50/60 Hertz DK power frequencies figure into this? Yes. No. Tesla determined that we would run on 60 cycle for a couple of unrelated reasons. He had a quirk about doing a lot of things in multiples of three. He ran three phases in his 60 cycle work, but he also liked the motor design that 60 cycle offered. DK> I mean, since a wavelength at 50/60 Hertz is thousands of DK> miles, it seems one could perhaps determine such existed ... DK> and then, I guess, from what you are saying, treat it as a DK> huge "tuned tank." Well I did attend a lecture by two EEs working at NASA who did some "listening" with highly specialized equipment. They would set up heavy earth ground points and listen with amplifiers. Everywhere they went they heard 60 cycle at about the same intensity, so the US in any case does appear to be impressed with 60 cycle from our power grid. But 60 cycle is not a frequency that naturally resonates the earth. DK> The mind boggles at what might happen if Man could induce DK> enough in there to make significant circulating currents DK> happen...visions of melting iron ore veins and such... DK> volcanoes erupting and all at the utter extreme... There would be no "induction", "circulating currents" or disturbances. Tesla saw the earth as a giant resonator when electricity at the properly tuned frequencies was conducted into it. As a conductor floating in space it is nearly perfectly insulated, so it would be very low loss. Electrical energy conducted through the crust (not induced) would remain as a resonate standing wave (as opposed to a circulating current). Funny thing today however. My brother was telling me his vision of the same thing: earthquakes, tidal waves, volcanos. But he was confusing mechanical resonance with electrical resonance. Tesla was an expert with both, and once stated that given enough TNT it was possible to cause major fractures in the earth's crust by timing a series of detonations. The detonations he said, would have to be timed to induce a moving resonant wave, and the amplitude of the wave would have to be developed over a period of several months. But back to the wireless power transmission using cavity resonate properties of the earth. The way I see Magnifing Transmitter is more like a pump. The high voltage field maintained on the smooth toroid (air terminal) forces energy into the ground. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-02-94 00:12 From: Richard Quick To: Don Kimberlin Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Oh, BTW You were talking about shaped fields. You asked if the Tesla coil employed aspects of a shaped shield, then you said... DK> Or am I zooming off on a tangent? then I replied... RQ>No your shooting dead bullseyes. Then I described how the fields are shaped. You followed that with... DK> ...Sure sounds like being concerned with the shape of the DK> field being coupled to this Dumb Old Country Boy... No your not dumb at all. We are in complete agreement and I am very concerned with the shape of the field being coupled. "Shooting dead bullseyes" was meant to imply that your thought process had progressed forward quite logically after intial acceleration and that you had arrived at a conclusion that was correct and important to efficient design parameters. You also made it seem easy. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-04-94 01:24 From: Richard Quick To: Mike Procospo Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ > 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 flume duct. Ratios of coil height to width are important. Small coils (3" to 6" diam) work best with aspect ratios (height to width) around 5:1 - 4:1, larger coils (8"+ dia) 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. 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 dug that up as it pretty much explains things, and you may have missed the post. DH> What determines a certain plastics being good? The dielectric constant is not the factor to go by when choosing a coil form. It is really preferable to use a plastic with the lowest dielectric constant. The reason for this is you want the distributed capacity of the coil to be as low as possible. Capacitance in a coil reduces throughput, and we want the throughput to be as rapid and efficient as possible. The distributed capacitance in a coil retards the current peak that follows the VSWR (resonate rise). Coils have enough problems with distributed capacity from the length of wire, the closeness of turns, and the number of windings. No need to make things worse by choosing a plastic with a high dielectric constant. What is most important in choosing a coil form material is the dissipation factor. The dissipation factor of all commercial plastics has been calculated, and somewhere in this mess I have those figures. If my memory serves me correctly, the standard RF dissipation factors are based on a frequency of 1 Mhz, close enough to judge if the plastic is suitable for coil work. The next important factor to look at is the dielectric strength. This should take second place to dissipation factors if your goal is to build the most efficient coil possible. Proper con- struction, more than anything, prevents electrical breakdown. Even if the dissipation factor is very low (good efficiency) it is best to use the thinnest wall coil form possible. Turns of wire, coats of sealer, and hard plastic end caps will stiffen the coil some. Low density polyethylene forms (such as wastebaskets) give coils with very high "Q" factors (a measure of efficiency) but are difficult to work with, as this plastic is very flexible. As far as the electrical strength of a coil wound on a very thin walled plastic tube, it should not break down internally if THE WIRE IS NEVER ALLOWED INSIDE THE COIL FORM. Do not drill holes or introduce the wire into the side of the coil. A hole anywhere on the coil sidewall will cause a failure regardless of the di- electric strength of the coil form plastic. My coils are capped top and bottom with plexiglass plates that are approximately the same thickness as the coil form wall. I use two-part epoxy cement and I seal them airtight. It is OK to drill one small hole in the bottom plexiglas plate to equalize air pressure, but I do not. The air terminal capacitance (discharger toroid or sphere) is connected by lead wire (I just use the magnet wire and avoid splicing) from the top of the coil. The lead wire is "air wound" up to the terminal, with the turns about the same diameter as the coil, or a little smaller. You will see me doing this in the video when I set up for a low power test in the garage. The terminal capacitance must have a diameter greater than the coil form, or spark will break out; either from the top of coil, or from the air wound turns connecting the coil to the terminal. The other construction secret not covered in the video is the ground connection. Once the coil is wound and sealed I take the base wire and pull it up out of the sealant until it is free all the way to the beginning of the first turn. I clip off the excess wire, leaving about a 2" tail. I lay the tail on a metal block, and using a small ballpeen hammer, flatten it out as best I can. A strip of copper sheet about 3/4" by 2" is then cut from stock and bent slightly to match the curvature of the coil form. Solder the flattened tail to the back of the copper strip. Position the strip on the coil form just below the bottom turn of wire, and scribe a rectangle through the sealant all the way to the coil form plastic. Remove the sealer from the scribed area, then score and clean the bared plastic. I then use epoxy to bed the copper strip. This forms a high current grounding plate without drilling. Ground wire or strap (preferred) can be held in firm connection to the plate with tape or a large rubber band. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-01-94 23:53 From: Richard Quick To: Michaelj Scott Subj: TESLA COILS, VIDEO ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ MS> It seems that Ferranti Packard ( a RollsRoyce transformer MS> company ) is being liquidated by Corporate Assets Inc (416) MS> 962-9600 in Canada. I edited a little here, but you have a photo brochure... MS> What struck my eye was a setup with two Tesla coils with MS> toroid top hats... impulse generator, 6 capacitors, 6 sets MS> of spheres, 2 voltage divider stands, a computerized control MS> station, and several spares that was all new in 1991. Also MS> shown is a corona tester, a noise meter, FP spark gap MS> station with adjustable 25 cm spheres, FP Transformer test MS> system, 500 KVA with built-in 80Kv hipot coil which is MS> supplied by Canron 500KVA 150kw motor generator or Superior MS> Electric 190 KVA power stat. This type stuff is used to test the breakdown voltages of various power utility designs and equipment. There is an obvious need to test aspects of commercial power transmission systems before putting them into service. Testing includes lightning strikes, insulation breakdowns, power arcs, corona leakage, etc. That Superior Electric 190 KVA powerstat (variac) would be some- thing to cry over if it ends up sawed into pieces for scrap copper. This is HEAVY commercial grade equipment (think of the inductive delay as those variacs energized) that frequently goes by the pound... MS> There are 9 pages of color photographs of low frequency coil MS> winders, oil & silicon processing plants, ovens, pumps, MS> machine shop stuff, and tons of copper & aluminum inventory. MS> Delrin tubing, radiators, lightning arrestors, wire MS> bushings, solenoids, contactors, and finished products from MS> Ferranti-Packard like a 3600KVA auto transformer and a 1000 MS> KVA 23695Y/216Y/125W. Oh, for about $30,000 and a place to play with it all! MS> I'll make a copy and send you the original. It would make a MS> great video. If this stuff has more than scrap value, it MS> would be a shame to see it melted down before a hobbyist got MS> a chance at it. Maybe some of the Tesla society people in MS> the Buffalo area should be advised of the auction. I will do what I can to pass it along. One problem with this stuff... You can snap it up at bargain basement prices, for they do sell it for the scrap value, but you have to haul it away. Those Superior Electric powerstats I am drooling over; I know just enough about these puppies to know that a 190 KVA stack weighs in over 1200 pounds (545 kg), and would not be surprised to see it come in at one US Ton. The new stack ran many thousands of dollars, yours for probably $50.00. Money could be made if you could purchase items indivually, or small lots, and part them out to other coilers. The same powerstat is almost surely a motor driven gang of smaller variacs. You could split them and give several coilers a good jump in power levels. Similarly, die spun aluminum toroids and spheres are a few hundred bucks apiece new. But you need a place close to these auctions to hold the junk until it is sold and shipped. Moving this stuff around by commercial carrier costs $$$ because we are talking heavy metal to people who are paid by the pound. You have seen those full sized trucks that only carry one roll of steel, or one large I-beam, or one motor-generator... Humm, maybe I need to wait to build my lab until I find some commercial property with a rail siding... ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-04-94 23:08 From: Sjoerd Schaafsma To: Richard Quick Subj: Tesla coil Video ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Howdy Richard, We had my parents over this weekend and I mentioned your video to the old man. "Oh ya that sounds interesting," sez he. After 10 minutes or so it was, "Those guys are crazy," and I'm saying to myself "Far out!" We got as far as the long demo with the big toroid where you had the mini lightning storm before Pa was nodding off. I'll have to go back and watch the techie stuff with the explanations by myself. For the most part we fast forwarded to the action shots. You'll get more running commentary as we watch more of the video, and perhaps some intelligent questions after I've read some background material. A lot of the explanations are over my head, like a grade 3 math student being hit with ratios and rates. I can't see asking you to explain basics when I haven't read the files you sent on disk yet. I'm a firm believer in RTFM. BTW, once I have a backup copy of the video, you can be sure it'll be making the rounds here. more later. Sjoerd Schaafsma - An occasional 8 bit holdout [403]327-9731 Lethbridge,AB (1:358/17) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-03-94 16:37 From: Brian Thurston To: Richard Quick Subj: TESLA ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Hi Richard: I am not absolutely sure (grade 12 science class is a LONG time ago) so I will not contest his (Tesla's) earthly point of departure. By most accounts a brilliant man with limited social graces. BC, Canada (1:153/915) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-04-94 16:54 From: Richard Quick To: All Subj: Tesla caps 1/2 ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ I posted a two part message to Mike the other day detailing construction of a rolled type pulse discharge capacitor. Since the detail of this particular unit was pretty well covered, I will focus on other homemade types; the flat stacked plate type capacitor, a little on the salt water cap, and a little on capacitor theory as it applies to Tesla coils. I have seen several types of homemade stacked plate capacitors. The two types differ as to the orientation of the plate stacks. Some are stacked vertically, others are stacked horizontally. Before I go into construction details I should cover some of the advantages of flat stacked plate caps for use in Tesla coils and other high voltage applications. Flat plate caps have little or no no internal inductance. Rolled caps contain two or more plates which are spiral wound. Rolled plates exhibit some properties of coils, and they contain a certain degree of self inductance. This limits the size of the rolled cap for many, including Tesla applications. As plates grow in size, the self inductance grows, and the caps exhibit self-resonance that will interfere destructively with the oscillation of the Tesla tank circuit. The rolled cap that I posted about previously, is about as large as you can get in a single unit without having self-resonance drop below 1 megahertz. Flat plate caps are better adapted for pulse applications. Rolled caps have to discharge a long plate. The further away the free end of the plate is from the high current terminal, the longer it takes for the cap to discharge. In essence this distance is also an extension of the tank circuit wiring, as the plate gets longer losses increase. Again the rolled capacitor I posted previously is pushing the design limits of efficiency in this area. As the rolled cap gets larger, efficiency of pulsing drops off. Flat plate caps can be constructed to handle higher voltages. Rolled caps have efficiency limits in individual units as to the breakdown voltage. A single dielectric is used per plate. If dielectrics are made thicker, efficiency drops off, if made thinner efficiency increases, but they break down. Using standard materials, the rolled cap I posted about is at the edge of this design limit as well. Flat plate caps can be built for larger capacitance. The rolled cap, because of the design constraints listed above, won't give you much additional capacitance without increases in losses, problems with self-resonance, and lowering of the capacitor Q. The rolled cap that I posted is a good unit. I have built nearly 20 of these caps, and I use them a lot. But do not look to expand much on this design. It has passed through several improvements and I really think it is pushing the design limits in all of the important areas. Next we need to look at the flat plate cap, as there is much to be done yet, but first look at the dielectric. The best Tesla capacitor dielectric is low density polyethylene plastic. Whether you build rolled, stacked plate, or salt water caps you should look hard at this plastic before settling on anything else. It has an extraordinarily low RF dissipation factor for the cost. The actual "in use" dielectric constant on homemade caps using this plastic is right around 2. This is a little lower than the book value (up to 2.2), but homemade applications of this dielectric rarely have the close plate bonding that are achieved commercially. This dielectric melts at 100 deg. C. But because of the very low dissipation factor the plastic is subject to very little in- ductive heating. There is little loss, therefore little heating. When using this plastic however, it is imperative to cover in mineral oil to distribute any heat that is formed, suppress corona and displace air. Plastic caps not covered in oil are guaranteed to fail in seconds. Plates, dielectric, and oil MUST BE CLEAN!... BTW The cheapest and most common plate material is aluminum. In the rolled cap, aluminum flashing is available precut in a perfect plate width, and there are other widths available. Flat plate caps can use flashing, but it is frequently more cost effective to use foil. Now that we have established a few basics, lets talk plate cap design. The first type of flat stacked plate requires the cap be pumped down to a pretty hard vacuum to remove air. This is the horizontal stacked plate capacitor. Typically these are built in a Tupperware type storage box. Plastic, plate, plastic, plate etc. are stacked one atop the other to build up the value. The breakdown voltage is directly related to the dielectric thick- ness used. 60 mil poly sheet is recommended and will have a breakdown voltage in the Tesla tank circuit between 11-17 kv rms input voltage depending on the quality of material, and the cleanliness of the construction. Once the box is filled, and all parallel plate connections are made, high current busses are brought through the lid of the container and sealed airtight with hot glue. Then the lid is snapped on, and it too is sealed with a bead of hot glue around the edges. The next part is important: A single hole is made in the lid for the vacuum connection. A fitting is hot glued into the hole and a hose is attached to the vacuum pump. The cap is pumped down, then the hose is clamped off and disconnected with- out allowing air back into the cap. Submerge the hose in a bucket of clean mineral oil and release the clamp. This allows the oil to backfill the capacitor, and displaces the air that was removed. Once backfilled to normal pressure, I pump them down a second time, and repeat the procedure to make sure that all trapped air between the plates is removed. Air bubbles will form corona hot spots that will cause dielectric failure. The vertical stacked plate capacitor is much like the cap I just covered. But the vertical cap does not require pumpdown. A tank is used to hold the veritcally stacked plates and dielectrics. The unit I examined was built in a glass fishtank that employed no metal in construction. Dense foam padding was set in the bottom of the tank, and wedged in around the sides of the vertical capacitor stack to cushion it and hold it in place. The foam padding also reduced the mineral oil required to cover the stack. The reason these caps do not require pumpdown is that eventually the oil will displace the air trapped in the unit. A break in period of low voltage operation assists the removal of trapped air, as the pulsing of the cap vibrates the plates and agitates the air bubbles free. The disadvantage of the unit I examined was the glass fishtank. I have seen plastic waste cans that could be cut down for use as a tank in this construction. Higher Qs, higher voltage, and additional capacitance in stacked plate capacitors can be easily obtained. The trick is to use thinner dielectric. Now the dielectric strength of polyethylene is given as 1000 volts per mil, but this is not the case in Tesla coils. The standard breakdown voltages of a dielectric are calculated using DC voltage. When you run AC across the dielectric, the breakdown voltage must be divided by two. Then you must figure that the peak voltage from a AC sine wave is higher than the rms voltage most people go by. You meter won't see it, but your dielectric will. Then you have resonate rise in the Tesla tank circuit. To give you an idea of resonate rise in a tank, think about the tidal forces that can be created with timed pushes in a bathtub. It don't take much energy to push water over the side. The same principal operates in the tank circuit in a coil, especially with a synchronous gap system. The current pulsing back and forth from capacitor plate to capacitor plate causes a voltage rise that appears on the dielectric in the capacitors. The standard 60 mil poly is supposed to hold up to 60,000 volts per the book. I have blown holes through 60 mil poly with a 12 kv neon sign xfrmr in a Tesla tank circuit and my gap wide open. My pinky finger fit inside the hole. One of the neatest homemade stack plate caps I have seen was built by Bill Richards of T.C.B.O.R., the cost was pretty low, the materials came from his laundry room, the grocery store, and the drugstore. The only thing required was 56 hours of time in arranging the plates according to Bill. But he did end up with .03 uf 15 kv pulse capacitor in a five gallon bucket. It was quite a performer on his coil at 3600 watts! He shopped around for one gallon ziplock freezer bags with a 3 mil thickness. With a sharp scissors he cut the ziplocks off of the tops of the bags. Then he cut aluminum foil squares that fit inside the bag leaving a 1/2" of space around all four sides of the plate. So the plate had dielectric borders 1/2" on all sides. When two bags were stacked on top of one another, there were two layers of dielectric, for a total of 6 mils. Being practical, Bill figured correctly that the stacked bags would hold up to at least 1000 volts rms input in the Tesla tank. He built up stacks that had a value of about .45 uf each, with each stack rated at 1000 volts. Then he wired stacks in series. By squeezing fifteen stacks vertically into a bucket, and covering the whole thing in about three gallons of mineral oil, he got the required capacitance at the required voltage. Since the electrical forces are so well distributed among hundreds of dielectrics, he had plenty of breakdown safety margin. He gave the unit a couple of days to rest after construction, topping it up with oil as required, and gave her the works at 15 kv on a big coil. The heavy buss wiring never even got warm, and even though it bubbled out enough air to displace a few more pints of oil, it did not break down. It turns out that this is a homemade version of commercial pulse discharging capacitors. Stacked capacitor sections of very high value are placed in series until the proper voltage requirement is met. The cap has a very high Q because all of the plates are very close together, with a minimum of connections and bussing required. They deliver a very sharp pulse discharge. Bill's cap was pretty cramped in the bucket. Because of the square shape of the bags, a rectangular tank would have made things easier to fit and wire. But he ran his buss bars through the side of the bucket (sealed with hot glue) and by snapping on the lid, he could pick it up by the handle and move it around with ease. The novice coiler should think about the capacitor requirements and experiment some before beginning large scale homemade caps. Shop for materials; frequently a wholesaler can be found where bulk products (like mineral oil in 5 gallon pails) can be purchased for a fraction of the retail cost. But just because you don't have some big bang pulse caps on line does not mean that you should wait to begin firing a small coil. Nearly every beginner gets hir feet wet in salt water capacitors. Tesla used salt water tanks in Colorado Springs. A tribute to the genius of the man was his ability to develop his huge peak powers using low Q saltwater/glass caps. I do not recommend glass as a dielectric for coiling work. The dielectric constant is much better than plastic, but the RF dissipation factor is so great that they can rupture from dielectric heating (even in salt water the trapped water under the bottles does not circulate) and they always give a spindly, violet colored spark. Polyethylene again is the material of choice, and bottles and buckets can be assembled in a couple of hours that will fire small stuff. I mentioned he before that I have a friend who is firing 5 kVA coils, and still using banks of salt water caps to keep his investment down. As with any homemade capacitor, the salt water must be covered in oil to suppress surface corona. But the quality of oil need not be high, and the capacitors need not be exceptionally clean. A saturated solution of rock salt is all that is needed for the plates. I think I have accomplished what I intended to say on this subject. As always, I am happy to respond on any unclear areas, the need for additional information, or to note corrections. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-04-94 15:30 From: James Meyer To: Richard Quick Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ On 07-01-94, RICHARD QUICK wrote to DON KIMBERLIN and said: RQ> He had a quirk about doing a lot of things in multiples of RQ>three. He ran three phases in his 60 cycle work, but he also RQ>liked the motor design that 60 cycle offered. Three phase supplys make the motor design simpler. Even if Tesla had a quirk, he was still an engineer and chose the easier solution. RQ> There would be no "induction", "circulating currents" or RQ> disturbances. Tesla saw the earth as a giant resonator when RQ> electricity at the properly tuned frequencies was conducted RQ>into it. My reading leads me to believe that Tesla was expecting the resonance to be set up in the cavity that exists between the ionosphere and the earth's surface. Both the ionosphere and the Earth are conductors. They are separated by a pretty good insulator, the air. The Earth wouldn't be resonant by its self. As to whether Tesla actually knew that the ionsphere existed, I'm not sure. I think that he believed that even if it didn't exist before, that his high voltage coils would actually create an ionosphere. His big towers were (I believe) an attempt to get one of the terminals of his coils high enough into the air to enable it to couple energy into the ionosphere. The other terminal was already pretty well connected to the earth. The only thing Tesla didn't take into account was the fact that neither the Earth nor the ionosphere are perfect, or even very good, conductors. The losses involved would make the transmission of power through either one very inefficient. Even though the electric power companies today use an "earth ground", they don't try to pass any current through the earth. The ground is there for safety purposes. RQ> Funny thing today however. My brother was telling me his RQ>vision of the same thing: earthquakes, tidal waves, volcanos. RQ>But he was confusing mechanical resonance with electrical RQ>resonance. Tesla was an expert with both, and once stated that RQ>given enough TNT it was possible to cause major fractures in RQ>the earth's crust by timing a series of detonations. And then there's the story about a small device that Tesla made that could sense tiny vibrations in any object, amplify them, and feed them back into that object. The story goes that he clamped his pocket-sized device onto a steel supporting post in the basement of his New York laboratory and switched it on. Within a few minutes it had picked up the natural resonant vibrations of the building and surrounding land and begun to amplify them. Shortly thereafter, the whole area began to vibrate. It was after several cracks appeared in the building, and I think others nearby, that Tesla realized what could happen. He reportedly shut the device off and smashed it into little pieces so that nobody else could get hold of something that simple and yet so dangerous. Since Tesla very seldom made any drawings or notes for things that he built for himself, the exact configuration of that machine was lost forever. RQ> But back to the wireless power transmission using cavity RQ> resonate properties of the earth. The way I see Magnifing RQ> Transmitter is more like a pump. The high voltage field RQ> maintained on the smooth toroid (air terminal) forces energy RQ> into the ground. Again, I see something differently. The cavity you speak of isn't the ground. Jim, Durham, NC (1:3641/1) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-04-94 17:28 From: Richard Quick To: All Subj: Tesla, dischargers ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ >archives 11/94 Toroid Discharge Terminals A feature of the "classic" Tesla coil design is the sphere or ball discharge terminal. Tesla clearly was using spheres while he was developing the Colorado Springs oscillator, but during his work there he made the discovery of toroids. Photographs of the Colorado Springs machine clearly shows a brass toroid as part of the antenna mast to prevent corona leakage and premature breakout from the top of the extra coil. As we examine photos of the Wardenclyff machine he built on Long Island, it is clear that the entire tower was constructed to carry the giant toroid terminal. I do not have verifiable infor- mation as to the exact size of this terminal, but it is easily over 50' in diameter. Probably closer to 75-100'. Toroids perform several functions as discharge terminals on Tesla coils. They provide a large top capacitance. This top capacitance helps "cancel" the high inductance in the secondary coil, and increase throughput in the system. They break down at much higher voltages than other shapes. The donut shaped field distributes the charge density. Higher voltages must reached before electrical breakdown occurs. To the coiler this means longer, higher voltage spark. For those of you that have my video, you can see a 30% increase in spark lengths with no change to input power, the only thing I did was add a larger toroid and retune the system. Toroids sever the coupling. This may be a controversial statement on my part. But from what I have seen, appears to be true. A sphere discharge terminal does not want to separate from the field flux interactions between the primary and secondary. The primary field flux wants to couple the sphere discharger into the system as if it were another turn of the secondary. The spark from the discharger will frequently follow these lines of force, and seek to strike back to the primary. The spark discharge bends back down, and aligns itself with the magnetic lines of force. While this may be useful if you wish to visualize the size and shape of the field, it does nothing to increase your spark lengths. A large toroid on the other hand will establish a field identity that interacts destructively with the primary/secondary field flux. Since this destructive interaction occurs above the top turns of the secondary is does not affect the coil perform- ance or ability to process energy. It does however allow the spark to leave the system unaffected by the primary/secondary lines of force. This has the effect of allowing a clean getaway for the discharge and promotes those long strikes to the ground or other more distant objects. Toroids also have the beneficial effect of lowering the frequency of the secondary coil dramatically. By loading a large toroid on a relatively small coil, a very low secondary frequency is reached. Low frequency in Tesla systems means long spark. This way a small coil can give big coil performance. Because of this ability of the toroid to drop the frequency of the secondary to such low frequencies, it is important to have a very large primary available that can be tapped out to over 10-12 turns in order to regain the system tune. Larger capacitors may be added, but my experience shows that no additional power or capacitance is required to get big increases in spark production. Clearly the toroid is the ultimate in high Q dischargers in Tesla systems. Now go out and buy one. I can hear Dave Halliday now.... > "You Paid _HOW MUCH?_"!!! Yup, spun aluminum toroids are available commercially, and they run hundreds, even thousands of dollars each. My 20" wide by 5" high commercial toroid ran me over 350 clams. My ten inch secondary needs a toroid at least twice as big to achieve optimum performance, and as commercial toroids get larger, the price increases exponentially. I priced a 40" toroid for my coil at $2000.00 not including shipping, and they gave me a six month delivery time... So I built one for $35.00, and it works GREAT! I will never spend another penny on commercial spun aluminum toroids. Here are the brief instructions: I buy the 4" or 6" diam. polyproplyene flexible black plastic drain piping. This is made out of ridged plastic, so it does not have a smooth surface, but it easy to bend to form circles of varying diameters. I cut the flange off with a sharp knife, match the ends, and tape them together with wide plastic tape. Once a large ring is formed, I cover the entire surface with wide plastic tape to smooth out the ridges in the material. The goal is to have an even, smooth, surface. The tape choice helps with this con- struction, Mylar and other tapes have no stretch, and are difficult to work with as they wrinkle. I shopped several stores before I found a stretchy material similar to electrical tape. Tape is applied in overlapping strips, or bands, around the drain pipe 4" or 6" cross section. Some surface irregularities are OK. Once the ring is smoothed with a layer of plastic tape, I retape the entire ring with aluminum plumbers tape. This tape comes in two standard widths, I bought a large roll of each. Apply strips of plumbers tape over the prepared surface, make sure the entire surface is covered, and press out any wrinkles with a fingernail or tool. You should now have an aluminized ring. Cut out a circle of thin masonite, wood paneling, or thin plastic so that it will friction fit in the center of the aluminized ring. Place some blocks up under this panel, set the ring in place, and tape the edges all around on both sides with aluminum tape to hold it in place. Spray adhesive and heavy duty foil are used to cover both sides if the center plate. Roll out all wrinkles with a socket or a wood dowel. Works great, about 1/100th the cost. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-06-94 15:43 From: Richard Quick To: Don Kimberlin Subj: Electrical Octives ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Don, I picked this up from you in the thread "Phone Line Resistance" -=> Sez Don Kimberlin to Alan Hess about line resistance <=- DK> ...The other source of "echoes" in local plant is improper DK> terminating impedances. Matching the impedance of a piece DK> of copper in local telephone plant is an approximation at DK> best, when one understands that it's rare to ever have DK> a piece of wire that's even a quarter wavelength at audio 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.... Interesting thought. Could you please expand a bit on the relationship between 300 - 3000 Hertz and 3-1/2 octaves? Are there 1000 Hertz in an octave? I understand that a relationship of eighths and frequency exists, but I guess that my problem is that I have no musical talent, and I am at a complete loss as to how many Hertz make up an octave, or what the precise relationship is when spanning frequencies. I have a pretty clear understanding of the basic physics involved; I understand how string vibrations produce a note, I understand basic wave motion, frequencies, and harmonics. I have studied some transmission line applications in my coiling work and as a result I am very familiar with 1/16th, 1/8th, 1/4, etc., outputs. Given the current and voltage relationships in a transmission line it is clear and natural to me that an 1/8th based system of division applies when discussing a wavelength at a specific frequency. But when thinking about a range of frequencies, I don't understand how what is to me an "unintelligible" music based system (octaves) relates. Blame it on my music teacher. I really would appreciate it if you would take some time and explain this. Many times while reading/translating technical text from the past (1890-1910) I have seen the word "octave" tossed around by the old radio guys. Tesla uses it specifically on several occasions in the Colorado Springs Notes in context nearly identical to yours. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-06-94 21:00 From: Richard Quick To: James Meyer Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ This one is good folks... We are talking about Tesla's global power xmission scheme. RQ> There would be no "induction", "circulating currents" or RQ> disturbances. Tesla saw the earth as a giant resonator when RQ> electricity at the properly tuned frequencies was conducted RQ> into it. JM> My reading leads me to believe that Tesla was expecting the JM> resonance to be set up in the cavity that exists between the JM> ionosphere and the earth's surface. Both the ionosphere and JM> the Earth are conductors. They are separated by a pretty JM> good insulator, the air. The Earth wouldn't be resonant by JM> its self. Good point, and one I am happy to discuss. My reading and experi- mentation lead to other, perhaps more likely, explanations. >NICKOLA TESLA ON HIS WORK WITH ALTERNATING CURRENTS AND THEIR >APPLICATION TO WIRELESS TELEGRAPHY, TELEPHONY, AND TRANSMISSION >OF POWER. This is a fine product of a modern legal research is edited by Leland I. Anderson, published in 1992 (Library of Congress Cat. 92-60482, ISBN 0-9632652-0-2) by Sun Publishing, Div. of Boyle & Anderson, Denver, CO., 80219, and available from; 21st Century Books, Box 2001, Breckenridge, CO. 80424. This book is the transcript of Tesla's pre-hearing interview conducted by his legal counsel in 1916. The interview was precipitated by a number of pending court cases in the fledgling radio industry. One of the attorneys conducting the interview held an EE degree. Photos, patent covers, schematics, mechanical drawings, etc. were submitted by Tesla as the stenographer recorded his answers and explanations. None of this material was intended for print, most has never been published before, and there is no question as to accuracy or authenticity. His testimony and depositions led to a US Supreme Court decision in his favor 1943. JM> As to whether Tesla actually knew that the ionsphere JM> existed, I'm not sure. I would have to believe the answer was yes, but to Tesla I don't think it really mattered. He was very aware of the conductivity of low pressure gas, which mattered very much to the man who invented the waveguide. HV RF conduction through a low pressure gas; not radiation, not induction; is a key part of Tesla's global pathway. He clearly shows it in US Patent No. 645,576 & 649,621 filed Sept 2, 1897. He was refused these patents due to several objections by the patent office, namely that the machine could not work. Tesla invited the U.S. Patent Office Examiner in Chief, G.D. Seeley, to his Houston street lab. A demonstration and explanation was given to Mr. Seeley Jan 23, 1898. The patent that followed clearly states that the machine transmits electri- cal power in industrial quantities without wires. It's referenced in many places, and worth looking at. BTW, Lord Kelvin also dis- cussed various aspects of the idea with Tesla. Kelvin too came to Houston street lab during the month of September 1897, and stated afterwards that there were no flaws in the idea, and that it was both practical and reasonable. JM> I think that he believed that even if it didn't exist JM> before, that his high voltage coils would actually create an JM> ionosphere. His big towers were (I believe) an attempt to JM> get one of the terminals of his coils high enough into the JM> air to enable it to couple energy into the ionosphere. Not as Tesla explains it. Tesla stated that he had the technology to create a conductive channel from the air terminal of the Magnifying Transmitter into the lower stratosphere, where conduction would occur freely. I will quote Tesla from the legal document referenced above, pp 110,: NT> I have constructed and patented a form of apparatus which, NT> with a moderate elevation of a few hundred feet, can break NT> the air stratum down. You will then see something like an NT> aurora borealis across the sky, and the energy will go to the NT> distant place. I am not going to second guess Tesla here as to which specific apparatus, or how it was to be employed, but in the "Colorado Springs Notes" (Nolit, Beograde, pp 29, referenced prev.) Tesla shows us sketches of very powerful X-Ray tubes that require no return wire (single terminal bulbs like these were demonstrated by Tesla in 1891, and he held several patents). One of these tubes took clear X-Ray photos of Mr. Alley's skull at a distance of 40 feet with an exposure time Tesla estimated at 1/10th of a second. Tesla also had hard UV tubes (single terminal as above). Could these tubes perhaps ionize a conductive air channel into the lower stratosphere? Were the aurora borealis effects reported by Colorado Springs residents in 1899-1900 around Tesla's lab the system in actual operation? Me thinks perhaps... JM> The other terminal was already pretty well connected to the JM> earth. We agree 100% here. So would Tesla. JM> The only thing Tesla didn't take into account was the fact JM> that neither the Earth nor the ionosphere are perfect, or JM> even very good, conductors. The losses involved would make JM> the transmission of power through either one very JM> inefficient. Even though the electric power companies today JM> use an "earth ground", they don't try to pass any JM> current through the earth. The ground is there for safety JM> purposes. Tesla disagrees. He describes the planet and it's atmosphere as two nearly perfect conductors separated by a thin layer of dense non-conducting atmosphere. There is not space in this post to quote all of the text in the long titled reference I am using, but Tesla's counsel raised the very questions you do in 1916. Tesla responds to the question first with simple explanation, then analogue. When the attorney finally begins to understand his explanation, he replies that if what Tesla states is true then those who are using his radio patents are using it backwards... NT> With my system, I can convey to a distant point millions of NT> times the energy they transmit. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-02-94 01:25 From: Richard Quick To: Don Kimberlin Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ We were talking about the conductivity of earth grounds... RQ>What about earth resonate (electrically conducted) RQ>frequencies? DK> ...Does this get off into the area of Tesla determining the DK> resonant frequencies of the planet? Does the 50/60 Hertz DK power frequencies figure into this? Yes. No. Tesla determined that we would run on 60 cycle for a couple of unrelated reasons. He had a quirk about doing a lot of things in multiples of three. He ran three phases in his 60 cycle work, but he also liked the motor design that 60 cycle offered. DK> I mean, since a wavelength at 50/60 Hertz is thousands of DK> miles, it seems one could perhaps determine such existed ... DK> and then, I guess, from what you are saying, treat it as a DK> huge "tuned tank." Well I did attend a lecture by two EEs working at NASA who did some "listening" with highly specialized equipment. They would set up heavy earth ground points and listen with amplifiers. Everywhere they went they heard 60 cycle at about the same intensity, so the US in any case does appear to be impressed with 60 cycle from our power grid. But 60 cycle is not a frequency that naturally resonates the earth. DK> The mind boggles at what might happen if Man could induce DK> enough in there to make significant circulating currents DK> happen...visions of melting iron ore veins and such... DK> volcanoes erupting and all at the utter extreme... There would be no "induction", "circulating currents" or disturbances. Tesla saw the earth as a giant resonator when electricity at the properly tuned frequencies was conducted into it. As a conductor floating in space it is nearly perfectly insulated, so it would be very low loss. Electrical energy conducted through the crust (not induced) would remain as a resonate standing wave (as opposed to a circulating current). Funny thing today however. My brother was telling me his vision of the same thing: earthquakes, tidal waves, volcanos. But he was confusing mechanical resonance with electrical resonance. Tesla was an expert with both, and once stated that given enough TNT it was possible to cause major fractures in the earth's crust by timing a series of detonations. The detonations he said, would have to be timed to induce a moving resonant wave, and the amplitude of the wave would have to be developed over a period of several months. But back to the wireless power transmission using cavity resonate properties of the earth. The way I see Magnifing Transmitter is more like a pump. The high voltage field maintained on the smooth toroid (air terminal) forces energy into the ground. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-05-94 00:32 From: Don Kimberlin To: Richard Quick Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ ...Mike Procospo wrote to all: MP> I'm interested in making a telsa coil for a little MP> experiment of mine, could any of you write to me with some MP> information on how I would go about doing this? Thankz a lot ...Looks like it's time to rewind the tape and start it over again, Richard Concord,N.C. (704)792-9241 (1:379/37) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-07-94 16:59 From: Dave Halliday To: Richard Quick Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ RQ| DH> Just dropping a note to let you know that I am still | DH> incredibly busy... RQ|Yes I knew you were out there lurking, and figured you were |overworking yourself. I hope you have been saving stuff. You bet! Been hitting the [S]ave button frequently! Things have always slowed down during the summer and I was expecting the same but it kept getting busier and busier - I kept putting off hiring another person because I knew that as soon as I did, it would go back to "normal" summer business and we would be sitting around staring at the walls... Right... Only problem now is that the durn cash drawer gets too full to close - gotta take it to the bank every few days - either that or shred the stuff... DH> I was wondering about the current regulation going into the DH> pole pig - you are using an arc welder. I have several DH> baseboard heaters and I was thinking of paralleling a couple DH> of those - lossy but hey! RQ|Well, there is no doubt that using pole pigs in experiments |like this requires some hefty ballast. For those that have not |been following this for over half a year, I will restate. RQ|A "pole pig" is one of those electric utility cans that sit on |high voltage power supplies they are be reversed. The cores on |these type xfmrs are "shell" wound. They do not saturate, and |they will dim an entire neighborhood unless they are |externally current limited. You are firing your coil and inadvertently browning out the entire neighborhood. Over the wolverine sound of the spark gaps, you hear a muttering noise, you turn around and it is your neighbors, carrying torches, storming the gates of... RQ|I have used an arc welder in series with one leg of the 240 |volt input on the xfmrs (when run for HV supplies) to limit |current. In this use, the shunted core of the arc welder |performs the | pounds of iron core and copper wire here. The resulting |inductive delay is real, and it takes a second or two for the |current flow to stabilize through the control circuits. This |may not seem like a problem, but it is like driving a strange |car with gross oversteer. Learning to handle the controls |smoothly can be a bit nerve wracking at first. I can imagine, especially if you are tinkering with the setup: adjusting the gaps, providing different discharge paths etc... Kinda like a phase-lock-loop on a bad hair day! I have worked with the 4069 PLL chip and that is a really nice one unless you have the error-voltage filter time constants set too high - it is like trying to heard a bunch of cats getting it to settle down! RQ|Another common method used to current limit pole pigs is |resistive ballast. Paralleled high load resistance is added |resistive ballast. The problem with these are two fold; things |get very hot in a hurry (which is really no problem in winter, |but in a garage in August...), and there is a greater voltage I was figuring this would happen... |drop across the primary in the pig than is typical of purely |inductive ballast. The advantage: the power supply limited |with resistive ballast is smooth as silk; no inductive delay, |the power comes up surely and slowly, no tugging on the |variacs, and no sparking on the variac brushes. NICE! DH> The work on the controller is going well - I have not DH> hooked it up to the variacs yet - it's still at the store DH> but it works well. Anyway, I will keep you posted RQ|Sounds great! I will be writing it up in the TCBA news when I get everything up and running - should be a fun project by itself! ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-04-94 14:00 From: Richard Quick To: Mike Procospo Subj: Tesla Coil,xfmr,1/2 ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ > From archives ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 11-05-93 From: Richard Quick To: All Subj: 10KVA Tesla Coil ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ If you are interested in making a high voltage, high current, power supply, I can tell you how to do it for free.... First call the local neon shop(s) and tell them that your working with Tesla coils. Ask them to hold all of their failed xfrmrs so you can pick them up. Make sure you talk to the boss or foreman, and tell them that you want dead units. I have never had a shop turn me down for free cores. They are happy to get rid of them. There are two types of failed neon xfrmrs: warranty units, and old junk. The local shop must return units that fail within the two year warranty period back to the distributor for credit. Old junk (older than two years) you can pick up for free right from the local shop, but I also scavenge from the distributor. Ask where the failed warranty units go. If you can locate the distributor who sells wholesale, and handles failed warranty units, you have found a gold mine of high voltage xfrmrs. The distributor removes the PLATE from the xfrmr for return to the manufacturer, and throws the unit away. The manufacturer credits the distributor for the plate, as the shipping is too expensive. The cores go to the dumpster. After locating your source of failed units, be selective. Try to bring home the high current units. Ratings commonly used are 9 kv, 12 kv, & 15 kv, with common current ratings of 30 & 60 ma. Once in awhile you will come across a 120 ma unit. I grab all of the high current units (60 ma+) I can get in these voltages. First test your units. Use wire with a 15 kv rating or better. This wire can be obtained where you pick up the transformers. If you ask they will usually cut you off a few feet for free. I prefer using the solid polyethylene core from RG-213 coax, as it will withstand the voltage with gobs of extra safety margin. Draw an arc from the HV bushing to the case, one at a time. About 50% of the "failed" units I pick up are just fine and need nothing other than a clean up. There is nothing wrong with them. Often shops get these units from signs they have dismantled, and they just toss them into the junk pile with the rest. The other 50% are bad. Either one, or both, of the HV windings have broken down. These units can frequently be repaired. Remove all hardware, and insulators if possible. Take a hammer and a chisel and remove the cases by splitting them down the corners. Break off any stubborn insulators, but preserve the lead wires. You are left with a block of tar. Set the unit outside when it is very cold, or place in a freezer, and let it freeze solid overnite. The next morning, short the high voltage lead wires (you preserved them!)with a clip lead, and connect 110 volts across the primary. Since the cores on these transformers are shunted, they may be shorted without harm or blowing fuses. Let the unit cook for 15-30 minutes (varies with size & temp). Disconnect your leads, and with the chisel and hammer, chip a groove around the block. You want to score a groove lengthwise that will allow the block to cleave in two. Then, starting from one end of the block, chip until you hit the core, then do the same with the other end. Pry and chip the tar away from the core until the xfrmr is free. The core may then be disassembled, and the windings removed and examined. Kerosene and a stiff brush will clean up the windings and core of any remaining tar. The "cold-cook" method is fast and it works well. Frozen tar chips away cleanly. The "cooking" warms the core, softening the tar, and allowing it to release. The only other ways I know to free the cores are long soaks in solvent such as kero or gas, (the nasty waste does make a good tar crack filler), or melting out the tar with external heat from a fire or oven. Most units fail when the high voltage breaks down the tar insul- ation. The resulting carbon track shorts the winding. Simply removing the tar brings them back to life. Other times the coils break down internally. In this case I discard the winding after disassembling the core, and replace it with a good winding from another unit of the same model with the same type failure. While the core is apart, you can beef up the current output by removing a few of the shunting plates between the windings. Never take out more than 2 or 3 of these plates per side, as the additional power output will burn out the secondaries. Generally I get about 70-75 ma out of 60 ma units after I have finished. Rebuilt units need a little protection from the high voltage secondary outputs. The first thing I do is solder on a new lead wire to the high voltage windings. The HV secondaries are wound with very fine magnet wire, in the 30 ma units the wire is not much thicker than a coarse hair. Once a good solder connection is made, bed the connection and the first 1/2 inch or so of lead wire to the top of the HV winding with hot glue or clear epoxy. The lead wire need not be anything special, any thin insulated stranded wire may be used. Heavy wire increases the chances of a failed connection due to mechanical stress. When setting the unit up to fire you simply have to route it on insulators. The windings themselves are wedged against the core to prevent vibration. I have seen wood, bakelite, and plastic wedges used commercially. What I like to do is to soften up some 30 mil polyethylene plastic sheet in boiling water, and heat the core in a warm oven. I wrap dry softened plastic around the core and gently force the windings down on it. Once cooled, the windings have some insulation from the core, and they will not vibrate. The base wire from the HV windings must be grounded to the core. Use the original grounding point if possible, if not you may split the core apart slightly with a thin blade and insert the wire into the gap before you clamp the core back up. If required you may splice on a small piece of wire for added length. Neon sign transformers that have been rebuilt may be fired dry. The tar used to pot the cores for neon use does not really insulate well against the RF and kickback from the Tesla Tank. The units last longer when they are freed of the tar potting. The only other choice is to sink rebuilt units in mineral or xfrmr oil which is a very good RF insulator. I choose to fire them "dry"; it works, and there is no mess. Neons may be run in parallel to deliver the current required to fire medium sized coils, and I have run up to 4000 watts with banked neon power supplies. The general practice is to run these banks off of 240 volt feeds controlled through a variac. Neons with matched outputs are run in pairs in these banks. The primaries are paired up in series, and the secondaries are all paralleled to the HV buss. Phasing is important here, and each transformer must be checked as it is added to the bank to ensure it is in phase with the other units. If an xfrmr draws an arc from a lead wire brought to the HV buss, the primary or secondary connections must be reversed. Neons typically have an efficiency of about 50%, in that they draw twice as much power as they put out. This problem can be resolved with the use of power factor correction (pfc) capaci- tance across the line. The pfc capacitors used are the same as for alternating current motors. The voltage rating should be at least twice the line current used, and I like a 4x voltage margin for long life. The formula used to determine ballpark pfc is as follows: 9 10^ C = Corrected kVA ------ 2 2(pi)f e^ This should read C = Corrected kVA times (10 to the ninth power) over, (2 pi times f times e squared) C = required capacitance in microfarads f = frequency of applied voltage e = applied voltage Corrected kVA is determined by dividing the volt*amps (watts) output of the neon sign xfrmr by 1000 Using a pair of rebuilt 12 kv, 60 ma neons, with 2 shunting plates removed from the core next to each HV winding, and power factor correction capacitance, you can get a nice 1.5 KVA Tesla power supply with over 90% efficiency. Total cost: $5.00 for the pfc capacitors, and a few hours of time. I have unpotted dozens of neon transformers from many different manufacturers. I have tried to make this as informative as possible, and have checked it over for mistakes. If I have erred, or was not clear on something, please let me know. Use common sense, and don't expect the first attempt to work out. On my first attempt I managed to destroy a HV winding during the unpotting, as I did not know where the windings were located on the core. But once you see one core unpotted, with minor differences, you have seen them all. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-04-94 01:24 From: Richard Quick To: Mike Procospo Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ > 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, Plexiglas, or Lexan: 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 flume duct. Ratios of coil height to width are important. Small coils (3" to 6" diam) work best with aspect ratios (height to width) around 5:1 - 4:1, larger coils (8"+ dia) 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. 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 dug that up as it pretty much explains things, and you may have missed the post. DH> What determines a certain plastics being good? The dielectric constant is not the factor to go by when choosing a coil form. It is really preferable to use a plastic with the lowest dielectric constant. The reason for this is you want the distributed capacity of the coil to be as low as possible. Capacitance in a coil reduces throughput, and we want the throughput to be as rapid and efficient as possible. The distributed capacitance in a coil retards the current peak that follows the VSWR (resonate rise). Coils have enough problems with distributed capacity from the length of wire, the closeness of turns, and the number of windings. No need to make things worse by choosing a plastic with a high dielectric constant. What is most important in choosing a coil form material is the dissipation factor. The dissipation factor of all commercial plastics has been calculated, and somewhere in this mess I have those figures. If my memory serves me correctly, the standard RF dissipation factors are based on a frequency of 1 Mhz, close enough to judge if the plastic is suitable for coil work. The next important factor to look at is the dielectric strength. This should take second place to dissipation factors if your goal is to build the most efficient coil possible. Proper con- struction, more than anything, prevents electrical breakdown. Even if the dissipation factor is very low (good efficiency) it is best to use the thinnest wall coil form possible. Turns of wire, coats of sealer, and hard plastic end caps will stiffen the coil some. Low density polyethylene forms (such as wastebaskets) give coils with very high "Q" factors (a measure of efficiency) but are difficult to work with, as this plastic is very flexible. As far as the electrical strength of a coil wound on a very thin walled plastic tube, it should not break down internally if THE WIRE IS NEVER ALLOWED INSIDE THE COIL FORM. Do not drill holes or introduce the wire into the side of the coil. A hole anywhere on the coil sidewall will cause a failure regardless of the di- electric strength of the coil form plastic. My coils are capped top and bottom with plexiglass plates that are approximately the same thickness as the coil form wall. I use two-part epoxy cement and I seal them airtight. It is OK to drill one small hole in the bottom plexiglas plate to equalize air pressure, but I do not. The air terminal capacitance (discharger toroid or sphere) is connected by lead wire (I just use the magnet wire and avoid splicing) from the top of the coil. The lead wire is "air wound" up to the terminal, with the turns about the same diameter as the coil, or a little smaller. You will see me doing this in the video when I set up for a low power test in the garage. The terminal capacitance must have a diameter greater than the coil form, or spark will break out; either from the top of coil, or from the air wound turns connecting the coil to the terminal. The other construction secret not covered in the video is the ground connection. Once the coil is wound and sealed I take the base wire and pull it up out of the sealant until it is free all the way to the beginning of the first turn. I clip off the excess wire, leaving about a 2" tail. I lay the tail on a metal block, and using a small ballpeen hammer, flatten it out as best I can. A strip of copper sheet about 3/4" by 2" is then cut from stock and bent slightly to match the curvature of the coil form. Solder the flattened tail to the back of the copper strip. Position the strip on the coil form just below the bottom turn of wire, and scribe a rectangle through the sealant all the way to the coil form plastic. Remove the sealer from the scribed area, then score and clean the bared plastic. I then use epoxy to bed the copper strip. This forms a high current grounding plate without drilling. Ground wire or strap (preferred) can be held in firm connection to the plate with tape or a large rubber band. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 7-09-94 14:27 From: Terry Smith To: Richard Quick Subj: crossed wires ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ MC> .... crossing turns on a tesla coil... RQ> ... the lower turns can act as a low RQ> voltage "ground" point. Crosses between turns (especially on RQ> short fat coils with high interturn voltage increases) RQ> results in tiny breakdowns in the magnet wire insulation. In many RF chokes, closely spaced turns over most of a coil may be spaced out ncreasingly toward a "hot" end, in order to avoid both heating and voltage arc over problems. Terry (203)732-0575 (1:141/1275) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-08-94 09:27 From: Mike Procospo To: Richard Quick Subj: Tesla Coil,xfmr,2/2 (Tesla Power Supplies) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ RQ>Rebuilt units need a little protection from the high voltage RQ>secondary outputs. The first thing I do... Thanks this is gonna help me out a lot. (407)323-0025 (1:363/77) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-10-94 01:56 From: Richard Quick To: Don Kimberlin Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ DK> ...Mike Procospo wrote to all: MP> I'm interested in making a telsa coil... DK> ...Looks like it's time to rewind the tape and start it over DK> Richard Well it really isn't that bad. By now I have stored text files where I save my "Top Ten Tesla Requests", and what took hours to put together the first time can be cut, pasted, and revised if needed in a few minutes. Still, I try to add new material whenever I post, otherwise we would all get bored to death. I find myself learning more as I organize my thoughts and references in an effort to supply the most accurate and up to date information as possible. Other people direct and spin off topics, which broadens interest. There are a lot of requests for information on this subject. My archives of this and related threads go back to Oct 1993 and have been very popular. I have 95% or more of it on disk, along with related GIF files showing spark gap mechanical drawings. I will send a copy free to anybody who mails me a blank 1.44 mb floppy and a postage pre-paid mailer. Tesla is becoming an area of popular interest. I do appreciate the time that you and others have given towards intelligent input. Without quality people like yourself out here (and more joining in all the time) posting would be a waste of time. Thanks! ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-08-94 20:14 From: Richard Quick To: James Meyer Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Still rambling along about the Tesla global power scheme... JM> The only thing Tesla didn't take into account was the fact JM> that neither the Earth nor the ionosphere are perfect, or JM> even very good, conductors. The losses involved would make JM> the transmission of power through either one very JM> inefficient. Even though the electric power companies today JM> use an "earth ground", they don't try to pass any JM> current through the earth. The ground is there for safety JM> purposes. I wanted to point out the bottom line in this discussion before I take off rambling again. First and foremost: I am not positive that Tesla's global transmission system, using wireless stations for worldwide power and communications transmission, is possible. However, I am absolutely sure that Tesla believed to his death bed that his system worked. Looking at some of Tesla's history; patents granted, patent applications, lectures, notes, photos, drawings, and interviews, not to mention commentary by others; there emerges a picture of a most unusual, but very accurate, scientific mind. Given his docu- mentable record of logical thinking, one tends to defer to Tesla. It must be understood that much of the public perceptions of Tesla's work is tempered by three things; he was a boastful showman, he had odd (but elegant) personal habits, and he was talked about greatly behind his back; regardless, he was a first rate electrical-mechanical engineer and theorist. He sunk practically every penny he ever made (well over $2,000,000 by 1915) above room, board, and clothing, towards his oft stated lifetime goal of bringing electrical power and communications to the entire globe. He succeeded with low fre- quency AC (the "modern" Tesla Polyphase system still in use) prior to 1887. By 1891 he had radio patents, lectured on single wire power transmission systems and was showing off his single terminal bulbs. His work progressed, (despite the setback of a fire), at a feverish pace through the mid 1890s. Tesla developed multiplexing, base feeding resonate structures, and sensitive recievers, to name a few. By 1897 the first wireless power transmission patents appear, and Tesla demonstrates the working model in his Houston street lab. In 1899 Tesla perfected Magnifier (three coil) arrangement as the power processor for the wireless system and peaks his experimental station at Colorado Springs in 1900. See text pp107: NT ON HIS WORK W/ALTERNATING CURRENTS and THEIR APPLICATION to WIRELESS TELEGRAPHY, TELE... NT> I had in my Colorado plant a current of 1,000 amperes in the NT> antenna. The biggest radio plants of today (1916) develop NT> something like 200 or 250 amperes in the antenna. Remember, NT> also, that my current was under a great tension. My current NT> was under a tension of 3 1/2 or 4 million volts, others only NT> 30,000 volts; so you can imagine the enormous difference NT> between the energy of the vibrations which I produced and NT> those in the present plants. I put that lower end peak power for Dr. Tesla = 3.5 gigawatts vs. Marconi and Co. upper end peak powers at only 7.5 megawatts. Tesla was running peak powers an order of magnitude larger than Marconi, and he was doing it years earlier. Some of the detailed description on performance characteristics of the Colorado Springs machine's tank circuits and resonators as it evolves into the powerful signal generator which is the heart of the global wireless system is inspiring... NT> It is a notable observation that these "extra coils" with one NT> of the terminals free, enable the obtainment of practically NT> ANY (emphasis in original) e.m.f. the limits being so far NT> remote, that I would not hesitate in undertaking to produce NT> sparks of thousands of feet in length in this manner. Owing NT> to this feature I expect that this method of raising the NT> e.m.f. with an open coil will be recognized later as a NT> material and beautiful advancement in the art. See Colorado Springs Notes pp79 for the above quote, pp115 fig. 5 for a dual resonator schematic that produces ball lightning (entry Jul 30 1899) pp 162 for another (Aug 26 1899), some wicked oscillator tank circuits and coupling ideas pp 154- 157, mid-August 1899; one of the parallel circuits here was later used to advantage on the Phermex 50 MHz accelerator in the 1980s. He relates that the experiments conducted at Colorado Springs station were very successful on an industrial scale system, and that the Wardenclyff plant was commercial by design. This brings me to conclude: either Tesla was lying, or he really had something. I propose that Tesla was the world's foremost expert in power processing systems, and that the Magnifying Transmitter with base fed open end resonators (extra coil, earth) was the culmination of his life's work in this field. Tesla stated over and over that not only was his theory valid, but that he had built, tested, and operated more than one system. Many notables of the era, Helmholtz, Lord Kelvin, and Seeley, to name a few, were throughly convinced Tesla was telling the truth... If he was telling the truth, then we are obligated at the very least to try to understand the system accurately. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-08-94 20:11 From: Richard Quick To: Dave Halliday Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ We were talking about external current limiting on xfmrs... RQ> these type xfmrs are "shell" wound. They do not saturate, RQ> and they will dim an entire neighborhood unless they are RQ> externally current limited. DH> Over the wolverine sound of the spark gaps, you hear a DH> muttering noise, you turn around and it is your neighbors, DH> carrying torches, storming the gates of... I wouldn't grin too much. It has happened and leaves one feeling somewhat humbled. Watching the towns people gather, torches in their hands and anger on their faces, is certainly merry fun... Until they come breaking down your door! I have a compressed air quenched gap that when fired at over 1000 watts (3, 12kv 30ma neons) requires hearing protection. The pure performance and peak power delivered by this gap is excellent in every respect, but the noise is not tolerable unless the gaps are enclosed. Remember too that externally limited xfrmrs (potential, pole pig, plate) require more sophisticated gap systems than neon powered coils, with most coilers going with rotary gaps at this point... I saw a museum coil fired once that had a rotary gap system made up of eight or so 1/4 x 20 brass machine screws mounted around the perimeter of a 5" metal disk. The disk was threaded onto one end of a Black and Decker pedestal mount grinder. It worked great, but the replaceable brass screws used for the rotating electrodes were melted, burned and ablated rapidly. It was not properly shielded and the gap pelted me with tiny BB like droplets of molten brass and hot slag that easily penetrated my clothes. The coil was running not much over 2500 watts with a 3 KVA potential xfmr. It was inductively limited by placing a large Superior Electric Powerstat in series with the primary of the potential xfrmr. I have seen a number of coil plans that show variacs, powerstats, autoxfrmrs, whatever, as an adjustable inductance (adjustable inductive ballast) in series with the primary of the step up xfrmr. I have found this practice questionable, though others will surely disagree. These variable xfrmrs are shell wound on an iron powder toroid. They are designed for low saturation, high efficient variable voltage transformation with moderate to high current throughputs. When they are used as a variable inductance to limit current, the performance is very quirky; either the current is all the way on, or it is all the way off, and there are only two or three turns of winding where you have any (very very sensitive!) adjustment at all between full on, and full off. BTW, another characteristic of these variable transformers is that when you short them (full on) they cook real fast. Some people have cut a small wedge out of the toroid core on these variable transformers when they are to be used as variable inductance. The modification is permanent, but will assist a big Powerstat in adapting to the new role of limiting current from it's designed task as a variable xfrmr. But, IMO, even if the variable xfrmr core is modified, resistive ballasting is still required for smooth and safe control. On the other hand, an arc welder core is designed with heavy current limiting in mind. A bit of resistive ballast along with the massive variable inductor helps with low power testing and start ups. Once the circuits are brought up to full power the resistive ballast aids in smoothing things out. The arc welder alone as ballast opens up at about 2.2 KVA, that is if you remember there is a 1-2 second delay and don't open it wider. Once running it is manageable without resistance. As far as what to use for resistive ballast: paralleled oven elements from scrapped electric stoves may be inexpensively assembled, electric heater elements (such as you already have) work well, a 5 gallon plastic bucket filled with water can be doped with a few teaspoons of baking soda (current is controlled by rasing and lowering wet electrodes), incandescent bulb racks have been used, and I have also seen ceramic toroids wrapped with nichrome strap that can be used as variable ballast for sale cheap at the local electronics surplus shop. DH> I will be writing it up in the TCBA news when I get DH> everything up and running - should be a fun project by DH> itself! Never a dull moment! ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-08-94 09:15 From: Mike Procospo To: Richard Quick Subj: Tesla Coils ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ RQ>> DB> How did you go about winding your coil? RQ>The first step in winding a coil is to select a coil form. Thanks again for you're help (407)323-0025 (1:363/77) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Date: 07-09-94 11:30 From: Dave Halliday To: Richard Quick Subj: Tesla Coils 1/2 ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ RQ|We were talking about external current limiting on xfmrs... RQ| RQ> these type xfmrs are "shell" wound. They do not saturate, | RQ> and they will dim an entire neighborhood unless they are | RQ> externally current limited. RQ| DH> Over the wolverine sound of the spark gaps, you hear a | DH> muttering noise, you turn around and it is your | DH> neighbors, carrying torches, storming the gates of... RQ|I wouldn't grin too much. It has happened and leaves one |feeling somewhat humbled. Watching the towns people gather, |torches in their hands and anger on their faces, is certainly |merry fun... I have a next-door neighbor who will be a prime candidate when I start firing at high power! He "retired" about 20 years ago and is bored stiff - always curious about what I am up to... Was interested in what I was doing when I sank the ground pipes into my front yard a few months ago. Tesla WHAT? |Until they come breaking down your door! I have a compressed |air quenched gap that when fired at over 1000 watts (3, 12kv |30ma neons) requires hearing protection. The pure performance |and peak power delivered by this gap is excellent in every |respect, but the noise is not tolerable unless the gaps are |enclosed. RQ Also, you had mentioned a fluid cooled gap - how's that one going? I saw in one of the articles in Wireless World about the old spark-gap transmitters where they had the gap located in a separate enclosed brick building. I will be starting with the stationary gap you told me about - several lengths of copper tubing inside of the PVC pipe with a fan blowing through it but I have visions of doing a rotary gap or one with a pulsed compressed air. I had thought that a commercial audio high-frequency horn driver could be used to "pulse" a flow of air and by varying the frequency you could adjust the timing... |I saw a museum coil fired once that had a rotary gap system |made up of eight or so 1/4 x 20 brass machine screws mounted |around the perimeter of a 5" metal disk. The disk was threaded |onto one end of a Black and Decker pedestal mount grinder. It |worked great, but the replaceable brass screws used for the |rotating electrodes were melted, burned and ablated rapidly. |It was not properly shielded and the gap pelted me with tiny |BB like droplets of molten brass and hot slag that easily |penetrated my Welders call these slag drops "dingleberries" There was an insert in my last copy of TCBA news for an advertisement for a rotary gap using titanium electrodes. Didn't mention a price though |clothes. The coil was running not much over 2500 watts with a |3 KVA potential xfmr. It was inductively limited by placing a |large Superior Electric Powerstat in series with the primary |of the potential xfrmr. I have heard that theaters used to have variable reactance dimmers for their lights - don't know if any are available or what their time-constants are but that would be another avenue to explore... RQ|I have seen a number of coil plans that show variacs, |powerstats, autoxfrmrs, whatever, as an adjustable inductance |(adjustable inductive ballast) in series with the primary of |the step up |to limit current, the performance is very quirky; either the |current is all the way on, or it is all the way off, and there |are only two or three turns of winding where you have any |(very very sensitive!) adjustment at all between full on, and |full off. BTW, another characteristic of these variable |transformers is that when you short them (full on) they cook |real fast. RQ|Some people have cut a small wedge out of the toroid core on |these variable transformers when they are to be used as |variable inductance. The modification is permanent, but will |assist a big Powerstat in adapting to the new role of limiting |current from it's designed task as a variable xfrmr. But, IMO, |even if the variable xfrmr core is modified, resistive |ballasting is still required for smooth and safe control. Hmmmm... Maybe there could be a way to move a wedge in and out of the toroid... Either that or rewind it with a heavier guage of wire... RQ|As far as what to use for resistive ballast: paralleled oven |elements from scrapped electric stoves may be inexpensively |assembled, electric heater elements (such as you already have) I will start out with that and go from there. I had these from a previous remodel and didn't throw them out because I figured I would find a use somewhere... RQ| DH> I will be writing it up in the TCBA news when I get | DH> everything up and running - should be a fun project by | DH> itself! RQ|Never a dull moment! You have that right! Also, just noticed that Tesla's Birthday is this Sunday, July 10th I think I will throw the main breaker to the house and then turn it back on! Fiat lux big-time! 206) 528-1941 (1:343/210)