Author Topic: Tesla coil project and other high voltage projects (Read 15898 times)

Rutger · « **on:** March 31, 2011, 03:21:35 pm »

Hi, I am looking doing a project with my son and we want to build either a small Tesla Coil (12" range), Jacobs Ladder or a "Antigravity Project" from the book 'Electronic Gadgets for the Evil Genius', but I am having a very hard time locating part for these projects. It is a nice book but there project cost estimate is way of the mark (by a factor of 10-20 more). And the only website I have found is the website from the book and charge an arm and leg.

Were can I buy high voltage capacitors, avalanche diodes and high voltage transformers in the 10KV range and higher. Does anyone know of a good source for these parts?

Rutger

mikeselectricstuff · « **Reply #1 on:** March 31, 2011, 04:17:10 pm »

Ebay is the best bet. For HV transformers, neon-sign transformers are generally the most available but this depends a lot on how popular neon signs are in your area, as well as in some cases regulations that restrict voltage/power, or mandate internal groundfault sensing electronics.

Oil burner ignition transformers are also good for small coils, but again availability depends a lot on the local market.
The only widely available species of HV transformer is the microwave oven transformer, but their relatively low voltage and high current capability make them difficult and more dangerous to use.

For capacitors, the usual method is to build an array of lower voltage caps, generally referred to as "MMC" - Multi-Mini Cap.

Zero999 · « **Reply #2 on:** March 31, 2011, 04:29:01 pm »

The classic is a flyback transformer from an old CRT which can easily be connected to an oscillator.

What about an insect killer transformer?

You can also make your own flyback transformer but it's not easy to make one up to 10kV without it arcing over.

Simon · « **Reply #3 on:** March 31, 2011, 04:34:20 pm »

Be careful with those evil genius books. I have one and I'm not at all confident that details are explained enough particularly with HT projects working straight off the mains ! I beleive there is a website the author sells the required parts from

Zero999 · « **Reply #4 on:** March 31, 2011, 05:37:10 pm »

Farnell sell control panel transformers for converting 208VAC to 600VAC down to 115VAC or 230VAC. You could run one in reverse to give 600VAC or 830VAC, depending on whether you need isolation from the mains or not. You can then use a capacitive voltage multiplier to give 10kVDC.

Whether isolation from the mains increases safety is debatable. If you use an isolation transformer and want the secondary to float, you need to ensure the insulation can withstand the secondary plus the primary voltage. The transformer I linked to above is only tested to 5000VAC which is just over 7kVDC and is not good enough for you so you'll need to connect the secondary to earth. If you're connecting the secondary side to earth then an isolation transformer offers little protection except for perhaps a broken neutral on the mains side or live neutral reversal.
http://uk.farnell.com/block/uste100-2x115/transformer-isolating-100va/dp/1177119

Simon · « **Reply #5 on:** March 31, 2011, 05:47:46 pm »

yes well my main gripe with that series of books is that the author only vaguely explains circuits and some of the explanations are a bit pseudo scientific. The book basically is trying to target audiences that might not neccesarily have an electronics background and skimps on a lot of needed detail so that you understand what your working on in the first place

Neilm · « **Reply #6 on:** March 31, 2011, 06:18:48 pm »

Quote from: Simon on March 31, 2011, 05:47:46 pm

yes well my main gripe with that series of books is that the author only vaguely explains circuits and some of the explanations are a bit pseudo scientific. The book basically is trying to target audiences that might not neccesarily have an electronics background and skimps on a lot of needed detail so that you understand what your working on in the first place

I hope the author highlights the dangers. At these voltages it does not take much capacitance to store leathal charges. Safety MUST be paramount.

Neil

Simon · « **Reply #7 on:** March 31, 2011, 06:29:01 pm »

he dose point out that the projects are potentially dangerous but I find the lack of clear information more dangerous

House91320 · « **Reply #8 on:** March 31, 2011, 11:13:24 pm »

Jacobs ladders are really easy all you need is a cfl old tv and some wire.

Psi · « **Reply #9 on:** April 01, 2011, 01:56:54 am »

got to love high voltage

Rutger · « **Reply #10 on:** April 01, 2011, 04:20:41 am »

Cool photo, what is the setup?

Rutger

Psi · « **Reply #11 on:** April 01, 2011, 06:38:18 am »

It's a TV flyback transformer with custom wound primary. Around 15kV from the flyback goes into a voltage multiplier (also from a tv) which multiplies it up in 3 stages to around 45kV.
(All that blue tape in the pic is just because high voltage wires are very stiff and don't want to stay where you position them.)

I kept the circuit diagram for that thing for so long and i probably still have it somewhere, but i have no idea where.

The circuit is very similar to this one i found using google, except that the circuit i used has one NPN and on PNP instead of 2x NPN
But otherwise its very similar, two transistors, two resistors and two center tapped windings.

mikeselectricstuff · « **Reply #12 on:** April 01, 2011, 04:16:56 pm »

Quote from: Psi on April 01, 2011, 01:56:54 am

got to love high voltage

Need more volts! Like a million of 'em!

http://www.electricstuff.co.uk/marxthree.html#t2

Zero999 · « **Reply #13 on:** April 01, 2011, 06:28:15 pm »

The high voltage inside a TV (above 1kV) is relatively safe because the flyback has a high leakage inductance so is inherently current limited and the capacitors are fairly low value (typically under 100pF). It's the lower voltage parts (150V to 500V) which have a higher current output and are more dangerous, especially the capacitors on the primary side of the SMPS.

racerxdl · « **Reply #14 on:** April 06, 2011, 01:22:33 pm »

WoW! Nice marx generator... I ever wanted to made one, but here I dont find good caps for it.

So I made Tesla Coil! (Double Ressoant Solid State):

[youtube][/youtube]
And it evens plays music:
[youtube][/youtube]

I am remaking the base circuit of it, I posted pictures at Flickr. Today I will test it again with the new base.

http://www.flickr.com/photos/61332248@N08/page2/

neoone · « **Reply #15 on:** April 06, 2011, 09:43:30 pm »

Nice. I wanted to make Tesla coil for quire few years now. Recently I purchased neon transformer 10kV/50mA from Tecnolux model 10050 so it's 500VA- http://tecnolux.com/Eurores.pdf. I hope that will motivate me to speed up the work

racerxdl · « **Reply #16 on:** April 06, 2011, 10:49:13 pm »

That is a good NST! I think you can push a meter of spark from it ^^ Maybe more

hacklordsniper · « **Reply #17 on:** April 07, 2011, 05:58:25 am »

racerxdl · « **Reply #18 on:** April 08, 2011, 06:11:04 am »

Very good DRSSTC!

What IGBT are you using? On mine I run IRG4PC50U with MUR860 in anti-parallel. 140A on Primary, 80cm sparks


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Author Topic: Tesla coil project and other high voltage projects (Read 15898 times)

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