The Tesla Coil Graduation Project

A gallery of images compiled from this project: The Tesla Coil Graduation Project at GridLine.PlasmaFire.org


 
Introduction                                                                                                

Lightning in the palm of my hands: certainly a commendable feat, but nevertheless I know isn’t feasible for the time being; then again, the power of nature’s electrical generation can be simulated through the use of man-made devices capable of creating thousands or even millions of volts.

But why do it anyway? For electrical engineering purposes, the dielectric (voltage-penetration resistant) strength of materials can be tested using impulse generators; other voltage-multipliers can also accelerate the particles used to generate x-rays among other healing radiation in hospital settings. However, one of the most-used (and most spectacular) uses of high-voltage generators is in the use of simulating lightning for entertainment and practical usage—sure, machines such as a Van de Graaf static electricity generator are capable of intermittent bursts of power up to several million volts at a few microamps, but if a need for high frequency, higher current impulses are required, enter the Tesla coil.

A Tesla coil, also known as an “air-cored resonant” transformer, works much differently than a friction-induced machine or a stack of storage capacitors that release power in a single burst of high energy. In fact, it is more analogous to something like the collapse of the Tacoma Narrows Bridge; the disaster was discovered to be the result of induced resonance (because the vortex-shedding of the wind resulted in small jolts of energy of a frequency matching the twisting period of the bridge). As a result of too much twisting from the resonance, the vulnerable structure of the bridge failed with a series of parts falling into the river below. With a Tesla coil, similarly, there is a resonant system set up that result in a massive amplification of power in the output terminal—what we see as a result of this buildup is an impressive display of arcs reaching out into the air for a grounded conductor.

Thus, this graduation project will focus on exactly what a Tesla coil can do, as well as the history behind it, the man who invented it, and the process by which it works. The following report will be documentation behind my research and construction of a real, working air-cored resonant transformer, and the uses of its creation.


November 16, 2005                                                                                                                

Awesome! The three neon sign transformers I ordered from eBay arrived this afternoon! They are under the US-based Franceformer brand—well known in Tesla coiling circles as solidly built devices that can take a decent amount of abuse from the high currents that could potentially back-feed from the primary tank circuit back into it.

These units were all identical types: model 9060 P-E, 60 milliamp (mA), 9000 volt units with a balanced mid-point ground on the secondary output. They were quite heavy too at 31 pounds apiece—certainly a heavy brick of tar and windings!

Later that evening, I took out a pair of coat hangers to build a simple Jacob’s ladder climbing-arc device (think of the old Frankenstein movies with the two wires and a rising spark in between them) in order to test-run one of the NSTs. It turned out that it was quite easy to shape the steel wires even though they were rather thick. After about 30 minutes of playing around to get the lower initiating gap, top bow-out, and alignment of the whole system right, I turned the switch to the Statco 10-amp variac (that my physics teachers let me borrow) on.

BzzzZZZZZT! BzzzZZZZZT! Sounds like a Jacob’s ladder to me! A small arc began at the bottom of the pair of wires formed into a V, rising quickly and branching out into a snaking arc of electricity and superheated plasma. When the arc broke near the top, another one began back at the bottom—classic movie images! The 540 watts (60 mA times 9000 volts) allowed most of the sparks to reach around 4-4.5 inches in length at full power—though I dare not do it directly for a risk of dangerous burns and a nasty shock! Overdriving the NST (as the variac could pump out up to 140 volts, 20 volts higher than the mains) didn’t do too much to the device except making the arcs a little hotter.

Photographing the climbing arc resulted in some interesting images. A timed shot of about 1-2 seconds revealed a “sheet” of flame that actually had intervals of arcs spaced somewhat evenly (due to the 60 Hz current and a decently calm airspace); I could see that the shape of the sparks did not change rapidly, but altered appearance as it climbed since the disturbance of the arcs from the air caused it to do as such.

November 17, 2005

The following night, I took the experimental Jacob’s ladder setup to the kitchen for some more “playing” around with. I decided to mix up some table salt and water to make a concentrated NaCl solution to drip onto the rods—doing so resulted in some beautiful, bright yellow sparks that illuminated the kitchen well due to electron excitement of the sodium atoms, releasing photons in the yellow range of frequencies; photographing the arcs, on the other hand, required me to turn up the F-stop setting to let less light pass, as the released light could overexpose the images. Either way, breathing in the initial fumes released from the salt solution would be a bad, bad thing!

How silly of me to not wipe the rods well! Turns out that some of the salt residue was left on the coat hanger wires, resulting in a partially-yellow flame after the picture-taking had finished…

November 18, 2005

Now it’s time to break out the rest of the neon sign transformers for some testing. I wired up one more 3-prong cord to test each of the two other NSTs individually on the primary side; on the secondary output, I took some alligator test leads, a ½” diameter length of CPVC pipe, and a paperclip, which I used to draw some arcs off the terminals. Well, needless to say, the two remaining transformers passed diligently with no problems.

However, there was something to be concerned, or more likely intrigued, about: when the paper clip was held too long at one of the output terminals with the NST at full power, the arc would heat the tip to white-hot, one time even dripping some molten steel onto the linoleum floor (so…my mom did notice!). Time to get a wooden board…

For “fun’s” sake, I decided to take some paper clips and photograph/film non-moving plasma arcs (contrary to the Jacob’s ladder from yesterday), by starting with a small (¼”) gap and using the CPVC pipe to draw one clip away from the other with the NST at full power. A generously humming 60 Hz power arc of super-hot plasma thus ensued, making a sizable flame about 2.5” across which partially melted the ends of the paper clips while emitting some flares of burning steel.

Ah…sparks! So let’s make some sparklers. I snipped the melted balls of steel off the clips, and started anew with pointed ends. The gap wasn’t to be moved this time, but instead was set at about ¾”. With the transformer driven all the way up, the paper clips quickly became white-hot, and more—they began to emit copious showers of flaming steel. Too bad it couldn’t last for long: there was a smoke detector close to the location where this was done, and the “electric sparklers” emitted a significant amount of smoke–who knows what’s in that gaseous stuff that I’m breathing in right now.

January 3, 2005

Finally…here’s the list of the requirements this device is to follow–a tough one due to cost constraints.

Tesla Coil Graduation Project device restrictions

Cost:

  • Will be cost-limited to no more than $450 including a power controller; eBaying and shopping in surplus sites is almost a guarantee.

General size and weight:

  • Will theoretically put out streamers and arcs up to 41″ long under one input transformer (540 watts, or 0.54 kW) and up to 82″ 56.4″ [reconsidered using TeslaMap] under two input transformers (1080 watts, or 1.08 kW); see more under Power/input for the type of input transformer(s) used.
  • Will have two circular platforms; the lower, slighly-larger one will contain the transformer(s), power factor correction capacitors, primary tank capacitor, spark gap(s), Terry filter(s), power input receptacles, etc.; the top, smaller platform will support the primary windings, secondary windings, coupling adjuster, top load, strike rail, etc. They will be made of durable, low-flexing wood and/or phenolic that may be stained and/or varnished for a high-gloss appearance.
  • Will have platform supports either of large, stained/varnished wooden dowels/3x3s or gloss-painted 2″ Schedule 40 PVC pipe with flat Schedule 40 PVC endcaps.
  • Will be less than four and a half feet high with the highest coupling of the secondary and a small, single top load.
  • Will be less than 30 inches in diameter; strongly recommended to be less than two feet in diameter.
  • Will be supported on three or four casters for easier mobility.
  • Will have a removable secondary to reduce the loading size.
  • Will weigh less than 100 pounds total (excluding the optional power controller).
  • Will have a “DANGER: HIGH VOLTAGE” sign clearly posted/attached to the front or top of the unit as well as on the optional power controller :P .
  • Will have the high voltage lines in the primary tank circuit well-protected and shielded from both people and equipment. Ceramic high voltage insulators may be used for critical points.

Power input:

  • Will use 120 volts at 15 amps (wall current) for easier demonstrations, overload-protected with a set of circuit breakers also working as the main power switches; it may be filtered using a dedicated unit inside the optional controller (more later). A pilot light below each breaker may be implemeted to denote their status in dark situations.
  • Will run on either one or two Franceformer model 9060 P-E neon sign transformers (export version–non-UL certified; 120 VAC in at 540 watts; 9000 VAC, 60 mA out)–preferably site-switchable (the coil can be run with either one or two) with the appropriate power factor correction capacitors and a Terry Filter for each unit. They will NOT be connected to the house ground, but instead will be attached to the dedicated radio frequency (RF) ground. Each Terry filter will have an easily-adjusted safety gap made of steel or brass balls attached to brackets on phenolic or wood.
  • Will use two or three 15-20 amp twist-lock plug-socket setups between the power input (maybe from the optional power controller) and the coil, depending on if there is an auxiliary input.

Primary coil:

  • Will use a flat spiral primary of 1/4″ soft copper tubing or flexible copper strip less than 1″ wide.
  • Will be supported on low-dielectric insulating material such as PVC pipe, phenolic, or cutting board.
  • Will use a method of easy, safe tuning, such as a fuse holder modified to clip on the primary windings.
  • Will use a copper-tube strike rail on insulating columns, preferably ceramic high voltage insulators for a better appearance.

Secondary coil:

  • Will be on either 4″ O.D. acrylic/polycarbonate 1/8″-wall, or 4″ I.D. thin-wall PVC drain pipe–thoroughly dried, sanded, and varnished before winding.
  • Will use 25-27 AWG magnet wire suitable for high temperatures, around 1000-1100 turns.
  • Will be wound on either a lathe or a homemade winding jig (preferably powered by a gear motor with variable control).
  • Will be coated in a thick layer of varnish such that the hand cannot feel the windings once the secondary is finished.
  • Will have a means of connecting a strong, safe RF ground as well as a “socket” for an easily swappable top load.
  • Will have insulating endcaps of acrylic or polycarbonate to help prevent sparkover; they will be glued on with clear epoxy.
  • Will be supported on a precise coupling adjuster on the upper platform to raise or lower the secondary form in order to adjust the coupling between the primary and secondary.

Topload:

  • Will be made with aluminum foil tape (typically used on ducts)/flexible ducting/a large Styrofoam ring, cardboard, and/or pie tins.
  • Will have a method of easily (but securely) attaching to the secondary.
  • Will be sized appropriately to throw out shorter-than normal sparks for demonstrations and portability; future experiments after the project has ended may use a larger topload(s).

Primary tank capacitor unit:

  • Will be of the MMC style, using polypropylene pulse capacitors or an equivalent of very high durability.
  • Will use megaohm bleeder resistors for each capacitor.
  • Will be covered by acrylic or an equivalent clear insulating material for safety.
  • Will have strong connection points, such as nuts or ball terminals.
  • Will have a method of safe discharging and/or removal if one or more capacitors fail; a safety gap dedicated to the tank capacitor may be used.

Spark gap unit:

  • Will be of the Richard Quick/TCBOR cylinder-type utilizing 1/2-inch copper pipes; the final coil may use one or two gap units for better quenching.
  • Will use either 4″ Schedule 40 PVC pipe (cheaper) or 6″ Schedule 40 PVC pipe.
  • Will have an AC blower or cooling fan for each unit for better quenching, and may have a baffle to direct the air into the gaps if the Richard Quick-type gap is used.

(Optional) power controller unit:

  • Will run the coil using normal 120-volt house current at less than or equal to 15 amps.
  • Will be constructed out of durable, low-flexing wood with a hinged lid for access to the components.
  • Will have all of its main controller parts attached to the house ground (circuit breakers, variacs; NOT output sockets!).
  • Will use two or three 115-volt circuit breakers; one is for the neon sign transformer(s), another for the spark gap fans, and one more for the non-variable auxiliary power. A line filter may be implemented between the breakers and the rest of the controller.
  • Will have at least one main 15-20 amp variac (0-130 VAC)–this one will be used for controlling power to the neon sign transformer(s). Another secondary variable transformer may be implemented to control the speed of the spark gap’s(s’) fan(s).
  • Will use a clearly-visible Emergency Stop button to quickly shut down the coil in the event of problems. A deadman’s switch may also be used for improved safety.
  • Will have a large warning lamp and/or buzzer that sounds when the variacs are energized; the coil itself may have a large warning light attached to the first platform instead, connected to the auxiliary power output.
  • Will use a key interlock to prevent unauthorized use; it should be on the Emergency Stop button.
  • Will use a set of pushbutton “enable switches” with indicator lamps to engage a set of motor starters/contactor relays to feed power to the main variac, the secondary variac, and the auxiliary power output.
  • Will have a set of meters reading the coil input voltage as well as the mains’ current draw.
  • Will contain a set of clearly-labeled output receptacles to connect the Tesla coil.
  • Will have one or two AC cooling fans (with fan guards) that activate when the main power is switched on to keep the variac(s) cool.

Want an idea about how the final coil and its controller “might” look like? Take a look at this draft: The Tesla Coil Graduation Project Design Sheet 1 (click on the image to view a larger version)

April 7, 2006

By now, many of you might be thinking, “What’s going on with this guy? Has he started building this thing at all?” Well…no, but I’m about to–school work, particularly my recent quarterly exams, have taken me downhill from focusing on any aspect of this project. Nevertheless, I have acquired about half of the components needed to complete this 1.08 kilowatt coil at this moment, mostly in the form of raw materials such as plywood, PVC pipe, varnish, etc. I also have the final coil plan on hand, designed and refined by a Tesla Coil design app, TeslaMap. Here are the general specs of what I have in mind:

Final Project Considerations

Design methods:

  • Most of the coil is heavily centered around designs made with a Tesla coil design program called TeslaMap. Various specifications including power input/output, capacitor requirements, MMC strings, and other electrically-related values are calculated using the application; verification and/or proof may be done by paper/pencil/calculator as part of the final writeup.
  • Designing the other portions requires pulling out a calculator and various drawing tools; this area includes making sketches of the base, locations of the components, and an overall view of the device.
  • I may use some community websites, including those within the Tesla Coil Ring, in order to help me make decisions as to what coil contruction/design methods are appropriate–expert advice is generally preferable for a new coiler like me!

Cost:

  • Umm…it looks like this project’s going to weigh down the wallet more than expected. Since my parents aren’t big on home renovation projects nor adept in material work, and the fact that neither are electrical engineers, nearly everything had to be bought off-the-shelf. Items including the pulse capacitors and acrylic tubing are not only absent from common places like Radio Shack and The Home Depot, but also expensive if not hunted down on the Internet properly.
  • All in all, this project will likely end up costing around $600 for all of the parts needed, somewhat over the original prediction back in January.
  • I shopped for commonly-found hardware in The Home Depot.
  • eBay was used to acquire only the neon sign transformers, and the Surplus Center was searched for a set of 50 uF power factor correction capacitors.
  • Other online venues searched for included McMaster-Carr, Allied Electronics, Digi-Key, and Alltronics.

General size and weight:

  • TeslaMap reminded me that doubling power input does not result in a doubling of arc and streamer length–see the first point under Power input for more information.
  • The two-platform system is still the method I’ll be using to contruct this coil, with the NSTs, tank capacitor, spark gap, and miscellaneous filter gear on the lower, and the primary/secondary supported on the upper–see more under Base and upper platform materials.
  • The largest diameter of the coil will be the lower platform, at 25″.
  • Total coil height is still estimated to be less than four and a half feet high–this will vary depending on the final upper platform height as well as the secondary coupling.
  • Three lockable casters will be (instead of a metal mounting plate, they are of the standoff bolt variety) located triangularly about two inches from the edge of the perimeter of the disk–I don’t plan on using four or more casters, because three will provide a sturdy surface even if the ground beneath the setup is slightly out-of-level.
  • Total coil weight, hopefully, will still end up less than 100 pounds. Carry handles might be implemented if this gets too burdensome.
  • What? I really think a “DANGER: HIGH VOLTAGE” should be put in–it’s a solemn reminder of the power of electricity, and it looks jut plain cool.

Base and upper platform materials:

  • The base will be constructed out of a dark-finished 1″-thick, 25″-diameter disk of smooth plywood.
  • Upper platform supports will be made of three dark-finished pine stair handrails–they’re about two inches in width and about an inch thick, with flat bottoms (that will face towards the center of the coil) and rounded tops (that will face outwards). These supports will be fastened with long wood screws on the lower platform, and if I get the gist of it, with nylon screws on the top platform where the primary and secondary coils are located.
  • The upper platform is to be a dark-finished, 0.75″-thick, 23″-diameter disk of level plywood with a 4.5″-diameter hole cut out in the center of it (for the primary form to pass through). Three slots about an inch wide, equidistantly spaced around the disk, will be cut from the outer perimeter to 5″ in, to allow for the primary tap to connect to the primary coil.
  • A height adjuster made of two toilet closet flanges and a wood disk, used to change the Q (the tightness or looseness of the transformer effect on the coil, also known as the coupling) of the primary/secondary coil setup, will enable me to raise and lower the secondary form to obtain the best performance out of the Tesla coil without getting damaging primary-to-secondary arcs nor a poor output. Hopefully through the current power levels, I’ll never have to actually adjust the secondary height, though. Regardless, 3″ worth of adjustment should be enough.

Power input:

  • Well, it looks like this coil will definitely end up using two of the three Franceformer 9060 P-E neon sign transformers (one is already used for a Jacobs Ladder built a while back), for a total input power draw of about 1080 watts (1.08 kw). It turns out that if I doubled the power input (as the old, original intent was with only one NST), arc length is not doubled. In fact, with one transformer, maximum theoretical arc length according to TeslaMap is 40.0 inches; adding a second ‘former only increased it to 56.4 inches–however, I do believe this will lead to hotter, brighter arcs than just with one NST alone.
  • However, even with two NSTs, I designed this so that I could actually use just one ‘former if I really wanted to; on the base of the device will be a set of switches that allow me to enable one or both of the units (as well as detachable cables on the high voltage outputs to select which unit to use). Each neon sign transformer will have its own set of power factor correction capacitors (100 millifarads total for each unit), so that the total power factor correction will always be nearly exact according to TeslaMap (99.5 uF for one active, 198.9 uF for both). The tank capacitor, at 48.89 nanofarads, was designed for both NSTs active, but with only one running, there shouldn’t be a problem in underpowering the setup–the system’s resonant frequency of 226.86 kHz is not affected by this change.
  • One 30-amp line filter will be implemented where the variac-controlled power first comes into the Tesla coil to help reduce dangerous high-frequency signals from backfeeding into the house.
  • A single Terry Filter (a highly-refined safety gap/RC filter network with metal oxide varistors, a.k.a. MOVs, for backup) designed for a 9-kilovolt system, will help protect the NSTs from damaging surges inherent in the coil when running. Since each transformer’s voltage output is equal, the safety gaps should not have to be adjusted for a lower breakdown voltage if I wanted to run the coil on only one NST.
  • Three 3-prong plugs will be used–one for the NSTs, one for the quench fan, and one for auxilliary power; however, the grounding prong will remain unused, since all usual power grounds on this system will tie to the RF ground instead. Thus, only the hots (black) and neutrals (white) will actually run

Primary coil:

  • I’ve been able to get my hands on a 50′ roll of 0.25″ O.D. refrigeration-grade soft copper tubing, perfect for the primary coil at this power level. The turns, about 10-12 total, will be spaced approximately a quarter of an inch from each other, and about an inch from the sides of the secondary form on the innermost turn. TeslaMap calculated that, with my current tank capacitor, secondary, and topload (more above and below), the tap point will be around turns 4 and 5 for an inductance of 6.33 microhenries.
  • The movable tap point will likely be constructed out of a modified fuse holder meant for small linear fuses; a heavy-gauge cable will connect this to the main gap. The fixed tap point, located at the end of the innermost turn, will be soldered to an identical cable connected to the tank capacitor.
  • This will be supported on three or six 1.5″-high polyethylene bars cut from a sheet of 0.375″-thick cutting board. They’ll have holes slightly greater than 0.25″ I.D. drilled within them, spaced the same as what I intend for the interturn increments–the coil will end up being about an inch above the surface of the uppoer platform; excess material will be used for the strike ring…
  • A strike ring, intended to attract the secondary streamers/arcs away from the lethal 60 Hz primary coil current, will be an incomplete loop of the same copper tubing bent in a circle around the perimeter of the upper platform, about 22″ in diameter. One end will be attached to the RF/secondary ground.
  • The strike ring supports will be made of, as said previously, will be made of excess primary support material. It will be raised about two inches above the surface of the upper platform, at least an inch or more from the last turn of the primary.

Secondary coil:

  • The form of the secondary coil will be a tube of 0.125″-thick cast acrylic pipe about 30″ long–the actual wound portion is about 21″ long, the remainder used for coupling adjustment, top endcap, and the corona ring (more below).
  • About 900-1000 turns of 24 AWG magnet wire will be wrapped, single-layer, around this form, with the windings touching one another. Several coats of clear varnish will be put on after the winding process is finished for more robustness and slightly better corona protection overall.
  • A 4.25″disk of polyethylene, likely from an unused section of the cutting board, will be used for capping the top end of the secondary coil; this will either be a press-fit affair. or small nylon screws will be be forced into holes around the perimeter of the disk, through the secondary.
  • A small toroid, made out of an 8″ styrofoam wreath ring and a 6″ disk of wood, will be covered in aluminum foil tape to become a corona ring, so that the possibililty of breakout from the top windings is reduced. The main toroid will be stacked on top of this, possbly spaced with a short section of PVC pipe and endcaps. The magnet wire leading off of the top of the secondary will be either soldered or bolted to the corona ring.
  • The bottom connection of the secondary coil, to which the RF ground is terminated, will either be a piece of copper sheeting epoxied to the secondary or just the wire connected via a spade connector. A heavy wire will lead to the RF ground connection block, to which the ground strap (or cable) will attach to.

Topload:

  • The main toroid, 20″ in overall diameter, will be made out of a length of 4 inch flexible aluminum clothes dryer duct (not the foil/paper kind–just the pure aluminum, more-rigid type) and a disk of wood about 12 inches in diameter–this disk will be covered with aluminum foil tape, as well as where it meets with the duct. A breakout point, possibly made with a small round-head bolt and a magnet, may be used to direct the streamers in one general area (and to promote earlier breakdown for demonstrations).
  • This toroid will be supported on a short PVC column, attached to a mating socket on top of the corona ring. Nylon bolts will be used in this setup, except for where the electrical connection from the ring to the topload is made.
  • A heavy wire will lead from the corona ring to the topload by way of a bolt and a crimp connection.

Primary tank capacitor unit:

  • Seems like the only way to go is the well-renowned, multiple-miniature capacitor (MMC) way! I’ve bought 25 Cornell-Dubilier 2000 volt, 0.22 microfarad pulse capacitors, of which 18 will be used in the final design.
  • The TeslaMap information suggested that the optimum larger-than-resonant capacitor is 49.5 nanofarads for about 4.01 joules of power; using the MMC calculator, two parallel strings of 9 2000 volt-rated, 0.22 microfarad-rated pulse caps (as said above) will result in 48.89 nanofarads and 3.96 joules–pretty close!
  • A 10 megaohm bleeder resistors, an absolute must, will be put across each pulse capacitor to drain the lethal high voltage after each run.
  • 4″ x 6″ perforated printed circuit boards, without the copper pads, will be used to hold the capacitors; I believe that two of these will be enough to construct the tank capacitor unit. They’ll be separated with nylon insulators to prevent arcing.

Spark gap unit:

  • Nothing has changed with the spark gap unit as it was planned back in January–it will still utilize the TCBOR-style of static gaps. A short length of 4″-diameter Schedule 40 PVC pipe will contain a set of 1/2″-diameter type-K copper pipe (the gap electrodes) separated about a half-millimeter from each other, with a bolt fastening them to the inside of the PVC pipe’s wall. Connections will be made to these bolts to select the gap sizes. This way, along with a variac, the coupling adjustment, and transformer selection switches, I can run the coil anywhere from zero breakout to a full-blown roar with white-hot, 6-foot arcs–hopefully!
  • The fan used to cool this unit will be a 100 CFM Broan bathroom fan blower unit, found in a closing hardware store called Hechingers several years ago. Sitting in my basement, it saw little use until now… The good thing about this blower is that not only is it overpowered for this coil (resulting in a cooler, better-quenched gap), but its output can slide into the 4″ PVC pipe almost perfectly with little play–therefore, all I need to make is a small wooden mount on the base to support the spark gap tube at the end.
  • A shield of some sort, perhaps made of wood, may be used to block viewers from seeing the harmful UV light emitted from the gap as the coil runs.

(Optional) power controller unit:

  • What power controller unit? Hah. I don’t have the time nor the extra money to construct one–the former problem seems to dominate, as I have only about a month left to build the coil and finalize a presentation.
  • Thus, I will end up using a pair of variacs to control this beast; one will be used for the NSTs, and one will be used for the spark gap quench fan. Auxilliary power will be tied to the quench fan variac with a removable outlet tap, since there’s nothing else to connect except the warning light mounted next to the fan on the coil. Perhaps some day, I can use the auxilliary output for a rotary spark gap.

Final TeslaMap coil design screenshots:

Main printout screenshot:

MMC Calculator (mine’s is 9 series capacitors for one string, with 2 strings in parallel):

April 13, 2006

I decided to break out my dad’s digital camera and take pictures of each and every piece that was bought/acquired for this project so far. It’s located inside the Gridline subsection gallery: Visual Bill-of-Materials as of 4-13-06. Remember, though, that most (not all) of the items in there will be used.

April 17. 2006

The first of a series of parts I ordered last week have started to come in. Today, a long package showed up at the doorstep from McMaster-Carr (mcmaster.com): a 36″-long acrylic tube which will be used for the secondary coil form. I still need to find a way to cut this material to length without destroying or splitting it (a very bad, not to mention relatively expensive situation!)…

April 19. 2006

The second online-ordered item arrived today: 25 Cornell-Dubilier 2000-volt, 0.22 uF pulse capacitors, for the MMC tank capacitor. Surprisingly, they were smaller than I had expected them to be–they’re about an inch and a half long by about three quarters of an inch in diameter–rather shocking (NPI) that each one alone packs nearly one joule of energy when charged to their rating! Small amount of energy? It’s pretty large, considering a photoflash capacitor only puts out 300-330 volts despite having a capacitance of 80-160 uF–being shocked by either the pulse cap or photoflash cap is no party, for that matter, because the current they can release in fractions of a second is in the hundreds of amps.

April 21, 2006

Two more online-ordered components came in, bringing the total to four out six; they’re two Corcom 30 amp RFI filters and six 50 uF motor-run capacitors for power-factor correction on the NSTs.

Finally…it’s Day 1, where contraction has been started on the coil. Well, sort of–I began to draw in the locations for the parts on the lower platform disk as well as the 3/4″-thick, 2′ x 4′ sheet of plywood for the some shelves and the upper platform. From an artistic/drawing perspective, I think that the lines shouldn’t be erased since they look kind of nice; I don’t know about the effects of pencil carbon and high voltage, though.

Three things that I did actually building were the electrical boxes housing the NST/quench fan/auxiliary power switches and a preliminary copper tubing, Archimedes spiral primary coil (that will eventually be threaded though six polyethylene supports on the top platform). Lessons learned from the latter? Don’t rush! Winding the primary coil, it turns out, takes hours of work–so far after 4 hours, I’m not even close to being done. The excess tubing was used for winding something of a strike ring…

April 22, 2006

For Day 2, I continued work on the upper and lower platform layout drawings today, and managed to finish them both. Shaping the primary coil is taking a lot longer than I expected, since resizing one turn requires adjusting all of the others; gap spacing needed to be about a half an inch from the center of one pipe to the next–partially why it’s been taking a while. Well, at least it’s starting to look like a primary.

April 23, 2006

Managed to finish, after about 8 hours of careful bending, a preliminary primary coil and a strike ring…whew! I also took out the 1/2″-thick, 2′ x 4′ sheet of plywood and drew in the remaining materials needed for the overall skeleton of the Tesla Coil; this included the low shelves on the lower platform for the high-voltage level, as well as the coupling adjuster disk and the toroid disk. I have to wait until Thursday before I can finally head off to my neighbor’s house (Mr. Bussom’s) to cut all of the marked material, sans the lower platform disk, and to build a coil winding jig.

April 24, 2006

Day 4. The fifth batch of online-ordered parts came in today, from Electronix Express, composed of perforated circuit boards, nylon hardware, bumpers, and plastic cable clamps. Now it’s time to start building an MMC bank…which is exactly what I did as soon as I came home from school.

Wow. That was fairly easy! All that had to be done was figuring out how many pulse capacitors can fit on each of the boards; I needed a total of 18 (two paralleled strings of nine), and it turned out that each perf board could handle exactly three across and three down. Taking an engineer’s scale, I proceeded to divide the board into equal areas; next, I tested out the placements, marking holes with a Sharpie permanent marker (whoops…making a mistake here or there–easily removed with rubbing alcohol), staggering them for better high voltage arc protection. Finally, I soldered the capacitors down in zigzag fashion. Repeat for the second board. 10 megaohm bleeder resistors, ordered from Digikey.com, still haven’t arrived, and they won’t until at least the beginning of May. Oh well…there are still many other things to be done in the mean time.

Thanks to Terry Blake of tb3.com for the perf board MMC method, used in his HUGE Tesla Coil! I even had to pay a tribute to him by holding the completed boards up to the camera.

April 26, 2006

Now up to Day 5 in the line of construction, I came home from school with one task in mind: varnishing the lower platform. Lessons learned? 1. Mix it thoroughly. Always. Looking closely at this photo, you can see a section of the disk where it’s significantly darker than the rest. “Oops” indeed. 2. Take the time and coat it evenly. 3. Protect the workspace–hence the spillages on the floor. Same photo as before.

Afterwards, I proceeded to drill the holes used for mounting the casters. Even without the washers and nuts mounted, the board and casters could hold my 115 pounds of weight easily (besides, one caster alone handles 150 pounds of weight!)–kneeling on the setup, of course.

April 27, 2006

Day 6. It’s the first one off to Bussoms’ house for some of the heavy-duty work on the Tesla coil: the skeleton, mainly, but also the coil winding process and some other main components. Today was mostly a cutting session for the 2′ x 4′ panels of wood; while Mr. Bussom worked on biting out the largest pieces with a circular saw, I used his bandsaw to slowly cut out the shelving and the disks for the coupling adjuster and toroid. Enough time was allowed for him to also cut out a 4″ section of PVC pipe for the TCBOR-style sparkgap.

At the end, Mr. Bussom didn’t have enough time to begin routing out the 1/2″-wide slots on the upper platform disk that will eventually be used for the primary coil support strips. Oh well…gotta wait until this coming Sunday to see it.

April 28, 2006

Today’s been a relatively lax day for me at home, bolting down the casters with locknuts, except for one thing: as a test, when I laid out the neon sign transformers on the lower platform and started to pull the back end of the disk towards me, *clunk*. The transformers were massive enough, and my mounting locations for them and the two back casters so “dead center,” that whenever the swiveling wheels pointed away from me on the backside, the whole platform would tip over! Bad news…now I have to relocate the casters to somewhere better.

April 30, 2006

Back to the Bussom’s for some serious work on both platforms; the upper disk’s primary support slots were already routed by now over the past few days by Mr. Bussom. First, we had to relocate the two casters that were causing the tipping from Day 7–meaning shifting them in an arc, still 2″ from the edge as before, closer to the NST that was nearest to the back end.

Second, here’s the nerve-wracking part: cutting the secondary form (the acrylic tube) to 30″ length…egads, it was a tense moment for me, because that material cost nearly $50 for a 36″ length! Since Mr. Bussom cut out the 4″ length of PVC tube from Day 6, I let him do this one too. Lessons learned? Masking tape works wonders for guarding the edge when using the hacksaw, and amazingly, with patience, he got it through the pipe with no cracks whatsoever, nor any major scratches. Fantastic–another tough moment is over.

Third, back to work: I then used the bandsaw again to cut out 1.5″-wide strips of polyethylene from the cutting board, used for the primary coil supports, while Mr. Bussom proceeded to mount down the shelves on the lower platform. I still need to drill the former for the copper coil to thread through, but nevertheless it’s starting to really look like a Tesla coil. To close for the day, we quickly designed (courtesy of Mr. Bussom for his skeching) and built a PVC pipe-bolt coupling adjuster and determined the height from the top of the lower platform to the underside of the upper platform to be 22.25″, allowing us just enough time to cut the staircase railings to length, mount them to the disks, and actually wheel the whole thing outside to head home for some varnishing work some time soon. By the way, the upper platform will not be screwed down with decking screws, but will use a set of nylon bolts fitted into holes on the railing ends as pins so that I can remove the whole disk if needed–toolessly.

May 1, 2006

Day 9’s one of those days that I wish that I didn’t have to repeat, but am obligated to: staining/varnishing for moisture and arc protection. As if Day 5’s repertoire wasn’t bad enough, now I had to take apart the coil base and varnish each and every component, sand them a random-orbit handheld, and put on two coats of clear varnish. The work’s not the hard part, but having to deal with the vapors and lacking a supply of paint thinner on hand is more than just a nuisance–it exacerbates my asthmatic condition, hah.

The first piece varnished was the lower platform since it was already stained back on Day 5; the shelves, upper platform, coupling adjuster disk, and support posts, being bare wood, were varnished next. Later that night, I sanded down the lower platform again and added a second coat (two layers were necessary on all the pieces); the other parts took on their first. It’s rather amusing how much of a difference in looks a simple layer of stain can do, never mind the enhancement the varnish makes.

May 2, 2006

So I said that yesterday wasn’t one I wanted to repeat. Oh well…need to deal with it regardless. I used Day 10 to resand all the pieces out, except the finished lower platform, and to apply a second coat of varnish. Second task was to reassemble the entire setup, as well as to begin placing down critical components like coupling adjuster and the upper platform attachment pins (bolts, actually). The trickiest part of mounting down the adjuster was centering everything correctly so that the secondary form stands up as vertically as possible, with respect to the upper platform; I used a small torpedo level placed against the tube for such a purpose.

Now it’s really starting to look like a classic Tesla coil!

May 3, 2006

Finally, Day 11’s one where I don’t need to maintain my integrity in the presence of volatile solvents! Most of today was simpler, faster work: wiring up the line-voltage side of the Tesla Coil, starting with the infeed cables (where 120V power is connected). I mounted down the junction boxes as well as both RFI line filters, and began to connect the “line” side of the filters with ring crimp connectors for the time being.

May 4, 2006

Day 12’s a pretty hefty milestone in this project: the first time the two NSTs not used in the Jacob’s Ladder setup have been powered up since November 18, 2005! Before that could occur, the “load” side of the NST RFI line filter needed to be wired into its junction box where the SPST/neon pilot lamp switches were, the power-factor correction (PFC) capacitors needed to be mounted, and all connections on the PFC caps needed to be terminated with male spade crimp connectors. It was a fairly simple process, though cutting, stripping, and tinning the rubber-sheathed two-wire cable proved to be more troublesome, because the outer jacket was so easy to cut open with scissors that I constantly nicked the inner wire insulation. I had to discard those sections, because they’d eventually split open, resulting in dangerous arcing, overload, and possibly fire. Unfortunately, there wasn’t enough time to work on wiring the auxilliary/quench fan line filter and its junction box; that will have to wait for later.

Once finished, I pulled out a set of alligator-clip cables, a variac, and a pair of paper clips…and fired up the neon sign transformers. What a familiar picture

May 7, 2006

Day 13 consisted of returning back to the Bussoms’ home and building the secondary coil winder. Most of the work went by fairly quickly, involving using leftover pieces of plywood from cutting the platforms and shelves (as well as some of Mr. Bussom’s own scrap wood), determining where to locate the end boards and clamp boards (a system where a threaded rod ran through the center axis of the secondary form, and by friction, two boards hold the form, using nuts and washers–no need for the boards to be circular, though), mounting the variable-speed drill as a motor to turn the form, and constructing a wire reel holder. A small variac was implemented to adjust the speed of rotation, so all I did was tie-wrap the drill trigger to the full-on position.

The hardest part of the day came when we needed to “machine” out a disk of polyethylene (from the remains of the cutting board) using a jig saw, since the band saw blade had broken back on April 30, 2006. Let’s just say that when Mr. Bussom tried to cut slowly, the area where the material contacted the blade would liquefy from the heat of friction and resolidify the joint behind the cut. Working more quickly as a counteraction resulted in a loss of accuracy, so now we had this “somewhat-of-a-disk” that needed to be filed down to just barely press-fit into the end of the secondary form. The aftermath was easier when he drilled out the top of the form for three nylon bolts to hold the endcap in place. *sigh*

Hopefully, the fun part will come when I finally wind and seal the secondary coil.

May 8, 2006

Scratch that last line from yesterday–a sore back is nothing to be excited about! Well, at least for the latter part of the secondary coil construction process. Winding the secondary coil was fairly easy, as [AVI movie] this clip shows; however, that was after I obtained some practice with working the variac speed control. controlling my right fingers quickly, tensioning the wire with a cotton-gloved hand, and recording with the camera (mistakes: [AVI movies] 1, 2, 3, 4, 5, 6, 7, 8, 9…and a few other unmentioned ones, heh). Overlapping turns were the biggest problem, but backing out of them wasn’t a big deal either; it only required turning off the variac and, by hand, slowly rewinding the spool of wire.

The biggest pain, as mentioned, came with  [AVI movie] sealing the coil, particularly the first layer. The speed of the turning form allowed me to put on a much denser coat of varnish than if the form were still, but it also presented another problem: bulging. The centripetal forces on the varnish, even at low speeds, caused some areas to become thicker than others. For the first hour after each coat (there were two), I had to watch the form turn, brush in hand, smoothing out any that appeared. After some halogen lamp-assisted drying (1, 2, 3) I let the form continue turning overnight.

May 9, 2006

Woke up at about 6:20 AM this morning to shut down the winder motor…and to head for *sigh* school.

After returning later that evening, I proceeded to remove the glassy-layered secondary, temporarily mounted it on the coil base unit, and attached the endcap with a set of nylon screws and nuts. After going out to pick up a few miscellaneous parts, I proceeded to wire up the auxiliary RFI line filter/junction box (diverts power to the quench fan, a warning lamp [indicates when the coil is live], and extra outlets), mount the warning lamp socket, and connect the crimp-sockets for the light and the fan.

It’s getting there

May 10, 2006

Day 16 began as soon as I came back from school: building a 4″ x 20″ toroidial topload for the secondary coil. Nothing difficult. Almost everything tedious, though; it was sort of enjoyable at first to cut out all the strips of adhesive aluminum duct tape, but eventually the work became more and more of a chore, especially for the ones going around the aluminum ducting (those strips had to be cut to the same length every time). Then there’s the ubiquitous resulting backing paper strewn about; recycling is definitely a worthwhile subject to consider.

Mounting it involved collecting a set of hardware, 3/4″ PVC pipe, endcaps, heavy-gauge wire, crimp connectors, and polyethylene tubing (for more insulation on the wire), and bolting the whole thing together. Temporarily mounted, the coil reached ~5 feet, about up to my head’s height–significantly taller than the original plan from April 7, 2007 (“Total coil height is still estimated to be less than four and a half feet high–this will vary depending on the final upper platform height as well as the secondary coupling.”), even with the highest primary-secondary coupling. Oh well…at least estimated maximum arc lengths are still longer than the coil is tall.

After adding the topload, it looks quite a lot more dangerous–but this project still has a while to go.

May 12, 2006

Interestingly, DigiKey e-mailed me a week ago that the delivery date for their batch of parts was Monday, May 15. Guess what was on my doorstep when I returned from school? Yes, the last set of online-ordered components…finally. The Terry Filter can now be built, as well as soldering down some bleeder resistors for the tank capacitors.

Small work today–I decided to change the horizontally-oriented TCBOR sparkgap into a vertical version, using a set of angle brackets and a closet flange that bolted onto the 4″ muffin fan. This is what it looks like now.

May 13, 2006

Simpler work today than most other days: I spent about three hours soldering down the bleeder resistors on the MMC boards, and proceeded to build a Terry Filter board, in accordance with this schematic. The 100-watt power resistors located right before the yet-to-be-mounted safety gaps were too large to be placed down on the PCB; they’ll be located separately instead, with motor winding insulation under them (as well as the filter board and safety gaps too) as a thermal/electrical safeguard.

May 15, 2006

Day 19–time to begin wiring the high voltage, NST output side of the primary circuit. Most of the work was straightforward, mounting the power resistors and the Terry Filter board section. Electric motor winding covering kindly donated to me by Winding Specialties (a local motor rewinding shop) functioned as an arc and fire-suppressant as well as better insulation from nearby components, while nylon nuts and bolts held the setup to the side shelving panels. A pair of CPVC insulator columns, built from four endcaps, two short sections of pipe, and steel/nylon hardware, acted as a hub for the transformer outputs to connect to the filter. Wiring the infeed lines came next, using clear vinyl tubing as additional insulation for thin-gauge wire, measuring out and cutting the wire itself, and adding the proper crimp connectors at the end. The high-side, as I call it now, still isn’t finished…one more side of the NSTs, safety gaps, the main gap, and the MMC section still need to be wired. I’ve got a lot of things for school in other subjects to deal with for the time being, unfortunately.

May 17, 2006

Today and yesterday were spent wiring up the other high voltage side of the NST to the Terry Filter and building a set of safety gaps for the Tesla coil, per typical construction methods–using chrome drawer pulls as the gap balls and a set of right-angle brackets to hold them up; I also used short lengths of 1/2″ vinyl tubing for insulating the bolt threads from producing excessive corona discharge. Motor winding insulation, like the material used to back the power resistors and the Terry Filter board section, still needs to be mounted, though. Nevertheless, it’s a great thing to see and hear the noisy arcs from the gap–I could imagine the shotgun-loud sounds emanating from them when the capacitor bank is in times of overload…egads.

Oh, and did I mention that earlier this week, I obtained a “Danger: High Voltage” sign from our local Grainger? Heh.

May 18, 2006

Not much work today…motor winding insulation was installed beneath the safety gap brackets, the “Danger: High Voltage” sign was bolted onto the top shelf, and the remaining piece of acrylic tube from the secondary form cutting process was installed as a warning lamp shatter guard. Looks pretty nice with the lamp on.

By now, the remaining work includes mounting the primary coil on the cutting board supports, wiring the primary tank circuit, building a corona ring, wiring the RF grounding system, and testing the Tesla coil out. Slowly, but surely…

May 21, 2006

Hmm…building a corona ring for the top of the secondary coil can be harder than initially planned! I went back to Mr. Bussom’s house today to pick up the rest of the materials left from the previous visit, as well as to cut out a 5″ disk of 1/2″-thick plywood in order to construct a small toroid with one 8″ Styrofoam wreath ring. The purpose of this topload is to help prevent breakout from the top windings of the secondary (in order to avert damage due to arcing); simple, right? Not quite. The process of building the toroid was easy, since the process was essentially the same as constructing the main topload on May 10, 2006, but mounting it proved to be a challenge: turns out that the secondary output connection point (a small metal hex bolt) didn’t have enough spacing between the form and the bottom of the plywood disk, so I had to drill a large 1/2″ hole to recess it. Then another problem came up; the little bolts (“pins”) holding the secondary top endcap in were inaccessible when the corona ring was bolted in place! Thus, I had to do a little loosening-tightening dance with the various bolts until everything came together…and now, the nylon bolts connecting the ring to the endcap is still a little too loose; oh well, better to not strip the soft bolt by overtightening it!

May 25, 2006

School. General business. Bah. They’re preventing me from completing the final portions of this Graduation Project, but oh well–better to take the time and be careful to end up with a good setup than some sloppier method. So what’s left? First, the TCBOR spark gap needs to be built; second, the primary coil needs to be mounted on the support strips; lastly, the primary tank and RF grounding circuits need to be wired up. Oh, and did I mention there needs to be a written report and possibly a PowerPoint on all of this when I present the project?

Today, Day 23 in the construction process, was spent preparing to build the gap. The only work done so far included cutting out 2″ sections of 1/2″ O.D. type-K copper pipe (as the gap electrodes) and polishing them with strips of emery cloth. The latter step took quite a while, as I had no method of turning the pieces using a motor for faster work. I wonder if all this copper dust is bound to be hazardous to my health…

May 31, 2006

Finally, another milestone in the project has passed, but not without some bumps along the way: the primary coil has been mounted down.

To start, a lot of things were learned while working this. First, when the project was originally conceived of, I intended on using the “thru-hole” method of securing the copper pipe into the polyethylene cutting board supports. This meant drilling a series of evenly spaced holes into the supports and threading the spiral coil hole-by-hole in. Well, as some of my closest friends know, I tend to do dumb things …like changing my mind at the wrong moment; so what did I do this time? I ended up trying out a method of slotting the strips, supposing that the copper pipe would slide in snugly. Simple? Wrong. When I tried to use a drill bit on a borrowed portable drill press from a neighbor of mine’s (not Mr. Bussom this time), idiotic was I to think that a drill bit could act like a milling bit–it hardly did anything to the plastic. So I took out a Dremel milling bit this time, yet it was even worse–sure, the bit started to bite into the material at first, but heating took place and left me with a melted end of a polyethylene support.

So…back to the original plan: thru-holes. I remarked the holes on the strips, and began to use the drill press to punch out the holes (properly this time!); unfortunately, the bit kept catching the end of the material, thrusting it loose from my grip, often with bad results–hence the two bruises here. To resolve that, I took out the vice (also borrowed from another neighbor, Mr. Miller), clamped in the strips, and used a hand power drill instead. *sigh*…done with that issue.

After sanding down the holes, threading in the pipe turned out to be much easier than I had thought: only friction was the real problem, as it kept getting tougher and tougher to move the strips around and around as more turns stacked up (1, 2, 3, 4); in the end, though, it was all worth the sweat. Proceeding drilling holes for the ends of the coil, I wire-tied the mounts down and sawed off the excess support material. Finished.

June 2, 2006

Lots and lots of work on Day 25, I can say. The majority of the effort today was focused on continuing construction on the TCBOR-style main spark gap (TCBOR = Tesla Coil Builders of Richmond, whose members pioneered this cylindrical gap); however, I had modified the design slightly so that the gap electrodes, instead of being bolted directly against the PVC pipe, would be suspended closer to the middle using a set of longer brass bolts. To make things a little easier, I drew up a 1:1 scaled diagram of the gap layout (here); this particular gap design contained eight 1/2″ copper pipe segments, each 2″ long, suspended about 7/8″ from the inside of the pipe with one brass bolt. This meant that each electrode could be individually adjusted for spacing without affecting the others–a good thing indeed.

Since I didn’t have any brass hardware on hand, that meant going out and picking up one final set of parts

After that short trip to The Home Depot, gap construction began. Marking out the holes with the diagram, pencil, and a triangle, I predrilled and finished out the eight boltholes, then began to work on the copper pipe. Since the material was so soft, though, the bit broke through very easily with little conflict (unlike drilling those primary support strips!). After making one gap electrode, most of the remaining work was just repetitious in machining the rest.

To close for the night, I used an OfficeMax promotion card as a thickness gauge to space out the electrodes to the proper width. After a wiring up the leads going from the safety gap to the completed main gap, the NSTs were powered up…ozone and a nice discharge emanated from the gap. It works!

June 3, 2006

The Tesla Coil works!

But, before I get to the good stuff, first the agonizing amount of work that was done today: I began by mounting down the TCBOR main spark gap, and proceeded to wire up the low-side RF grounding system (NSTs, Terry Filter, junction boxes, quench fan) with some crimp ring connectors, thin-gauge stranded green wire, and an aluminum bus strip. The lower connection on the secondary coil was connected to its own bus strip, which the strike ring will also connect to later.

The tank capacitor wiring came next; I needed to find a way to mount down the MMC boards without taking up too much room. Thanks to God, this idea came: use the remaining brass hardware I had, along with a set of nylon standoff spacers.

When that was finished, the long part began: wiring up the tank circuit–not that it was difficult, but working with thick-gauge cable takes quite a while. Beginning with the main gap, I went around to the tank capacitor, to a PVC insulator column (similar to the ones for the infeed power leads), to the primary tap (made out of a fuse holder, polyethylene tubing, and some shrink tubes), and back to the main gap.

Final dash to the end: the next step was to build a strike ring, done with a set of CPVC endcaps and pipe segments. After that, the final connections were made to the RF grounding system, a radio antenna was installed as a striking device, and a brass ceiling fan ball/chain pull was installed as an emitter (for easier breakout)

..and after 26 days of construction and nearly 7 months of planning, it is DONE!

———————————————————————————–

After dinner, my dad and I carefully took the coil outside, set up the aluminum water heater drain pan RF ground system (as a counterpoise virtual antenna instead of a real RF ground), variacs, power strip, extension cable, and camera. A fluorescent tube was placed in a nearby table for tuning sake. The TCBOR main spark gap at this time was only set to one gap segment, and the strike antenna/ball combination, for the sake of tuning as well, was set for a 6″ gap. (Setup pictures: 1, 2, 3)

We put on our earplugs (because we knew this was going to be loud), and I removed the shorting lead across the tank capacitor…

1, 2, 3. Power on!

The auxiliary variac was turned on first, resulting in the red warning lamp on the coil emitting an eerie glow. I threw the switch to the main variac, and turned up the voltage…

WOW! A crackly buzz from the main gap, and a powerful corona discharge from the brass ball lead to the antenna, with strong discharges occurring frequently. The first power-up passed!

Tuning had to be done to optimize the system at this power level, so I turned off both variacs, unplugged the coil, and discharged the main capacitor across the safety gap with a CPVC pipe partially covered with aluminum tape. I moved the primary tap 1/6 of a circle up, resulting in a slightly lower primary inductance, and powered up the coil again. Even more discharges emitted this time! Repeating this process a few times, I managed to find the sweet spot where the resonance of both coils was greatest. Removing the ball and disconnecting the antenna, the main toroid was now the only terminal to discharge from. Time to retap the TCBOR gap and increase the primary tank circuit’s power…(without riling up the neighbors, that is)

The rest is Tesla history. We’ve got a working 1.08 kW Tesla coil! Right now, it is capable of producing 30″ streamers with 3 out of the 7 gaps connected. I still don’t know how much longer they can get (up to the theoretical 56.4″, maybe?), but that’ll be for another night. Perhaps July 4, 2006.

Special thanks to:

  • God, for giving me this talent to use in order to glorify His name. All kudos to you.
  • My parents, for understanding me and being able to physically, emotionally, and spiritually support me so much in this project.
  • Mr. Ron Cannon, for being my physics teacher for two years and putting up with my constant talking about Tesla coils and black holes.
  • Mr. Charles Clay, for being my Graduation Project Class teacher and understanding what’s going up in my head.
  • Mr. Ron Nagy, for being an awesome physics teacher (though not mine’s) and a powerful encourager for whom he meets.
  • Mr. Richard Bussom, for taking time out of caring for his family in order to help build this device. 
  • Mr. Jim Miller and Mrs. Donna Miller, for lending me tools and materials, as well as emotionally supporting me overall on this project.
  • Mr. Allen and Mrs. Linda Schantz, for lending me tools, as well as understanding what a neighbor I am for making all this noise.
  • Other neighbors, for dealing with this noise!
  • My friends at school, at church, and online, for interest in this project.
  • Mr. Patrick Marks of Winding Specialties in West Chester, for magnet wire and motor insulation, as well as encouragement.
  • Kevin Wilson, maker of TeslaMap, for his excellent Tesla coil design program.
  • Chip Atkinson and the members of Pupman.com (the Tesla Coil Mailing List), for their ideas and suggestions.
  • Members of the Tesla Coil Ring and overall coilers and wannabe-Nikola Teslas in this high energy (pun intended) community, for their habitual nature of making dangerous things!

Page Last updated: June 22, 2006