Need help finding a few things for tesla coil. / Tesla Coils / Forums

Forums

4hv.org :: Forums :: Tesla Coils

« Previous topic | Next topic »

Need help finding a few things for tesla coil.

1 2 next

Move Thread

LAN_403

Arcstarter

Fri Nov 21 2008, 01:19AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

This might have belonged on general science and electronics or high voltage but it is for a tesla coil, and tesla coil forum seems to get more views.

Well, i am planning on making a small tesla coil, because i might be going to the next Arizona teslathon(Christopher Hooper's). I want something small and portable, also cheap and bullet-proof. I decided to go with a single microwave transformer with quadrupler. Reason for this is, i like how the sparks look,and to adjust power input, all you have to do is change rsg speed. I have the arsg, it is a 24 volt motor so i can use my 555 flyback driver to vary speed without changing anything(i have tested it and it will go from 0% up to 90-95%).

Well, it might not be the cheapest way to go, but i have been wanting to make it.

Well, what i need is a good high voltage choke, or many smaller ones, and in all it needs to be able to stand up to at least 10kv, and something between 20 and 30 henries(i would prefer 30, because that is what Steve Connor used).

I also need some good high voltage caps for the doubler, two 3kvdc and 3uf and two 1.5uf 6kvdc caps. Or, i could just get six 3kvdc 3uf caps, and use two in series for the 1.5uf 6kvdc cap if it would be cheaper. I could also use a bunch of 22uf 450vdc electrolytics like Steve did. Of course, i would need to buy some 220kohm resistors for bleeding/balancing, but it might cost less. I do not mind soldering a bunch of stuff ;).

I have the microwave transformer, arsg, and i am going to buy 10 .15uf CDE capacitors, all in series for 20kvdc and 15nf. That is perfect, as it leaves about 4kv safety margin, unless the supply does give out the full 10kv.

Also, what would you recommend for the doubler/deQing diodes? Either a bunch of smaller ones soldered together, or a few big ones? If i used a string of smaller(i would go with some 1 amp 1kv diodes) i would also need a snubber cap that is good for 1nf and 1kv and an equalizing resistor on each, which would just add to the cost. But it might be cheaper and more reliable.

Basic schematic.

Also, sorry if this post seems kind of weird, it is because i kept stopping right in the middle of typing, so i might have repeated something that i don't catch when i go over it :P.

Firefox

Fri Nov 21 2008, 04:59AM

Registered Member #1389 Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346

If you use 1N4007s, you shouldn't need balancing components. Just overbuild by 100% for voltages, and you should be fine. I know Mates' 1N4007 strings for his 300kV multiplier didn't use any kind of balancing, and they survived several direct shorts of the multiplier when the limiting resistor got bypassed by a spark.

Arcstarter

Fri Nov 21 2008, 05:01AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Firefox wrote ...

If you use 1N4007s, you shouldn't need balancing components. Just overbuild by 100% for voltages, and you should be fine. I know Mates' 1N4007 strings for his 300kV multiplier didn't use any kind of balancing, and they survived several direct shorts of the multiplier when the limiting resistor got bypassed by a spark.

Ah, thats good. Thanks. That sure saved me a whole lot of time and money :P. Well, i am going to use the 1n4007's, so now i just need the inductor for the charging reactor, and the doubler capacitors.

Edit: Yep, i can get 1000 1n4007 diodes for 10 bucks. But, i cannot use the mastercard, and paypal is all that place excepts. I am going to have to pay the same amount for 500 diodes

Firefox

Fri Nov 21 2008, 08:17PM

Registered Member #1389 Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346

If you go to Mouser, you can order 1000 diodes for $17, 5000 diodes for $55, or 10,000 for $100. These are based on Fairchild Semiconductor's version bulk rates. If you order fewer than 1000, other manufacturers have better prices, but Fairchild has the best bulk prices.

Arcstarter

Fri Nov 21 2008, 10:53PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Firefox wrote ...

If you go to Mouser, you can order 1000 diodes for $17, 5000 diodes for $55, or 10,000 for $100. These are based on Fairchild Semiconductor's version bulk rates. If you order fewer than 1000, other manufacturers have better prices, but Fairchild has the best bulk prices.

Cool!

Thanks alot, Sean.

Firefox

Fri Nov 21 2008, 11:21PM

Registered Member #1389 Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346

No problem. I'm building a multiplier right now from some cheap 10kV 1.2A x-ray diodes I got on Ebay, and microwave oven caps. Mine will be a six stage bipolar multiplier instead of a two stage bipolar multiplier. I'll compare notes with you when I am done.

If push comes to shove, you can use several MOT secondaries with the primaries shorted as chokes, though you would need 6 of them for the voltage. If I recall correctly, the typical leakage inductance of a MOT is around 5 henries.

Arcstarter

Fri Nov 21 2008, 11:34PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Firefox wrote ...

No problem. I'm building a multiplier right now from some cheap 10kV 1.2A x-ray diodes I got on Ebay, and microwave oven caps. Mine will be a six stage bipolar multiplier instead of a two stage bipolar multiplier. I'll compare notes with you when I am done.

If push comes to shove, you can use several MOT secondaries with the primaries shorted as chokes, though you would need 6 of them for the voltage. If I recall correctly, the typical leakage inductance of a MOT is around 5 henries.

Well, this

guys mots are about 15 henries.. So... that would not be good, i would have too low charging current.. dang.. Well, i am pretty much sure i want to build a dc resonant charging coil, so i will just have to keep looking. I am not going to rush this project, and i am going to go ahead and wind a new 4 inch secondary. The on i used on my newest 811a vttc video, my big sgtc video, and my 833c vttc video, is too short and too small wire, so it is closer to the primary and base of the coil which will also increase flashover risk and running sparks(same voltage and smaller space).

Arcstarter

Sat Nov 29 2008, 12:57AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Well, Xmas is coming up, so i will have maybe 200 bucks in all(from my family, and my parents will gimmie 100 bucks instead of presents if i ask nicely :P) so it is time to start finding stuff. Also, i am sure i want this so i am going to spend some REAL money to get it how i want. I am thinking about selling my pole transformer, so that would be maybe 400 or more bucks that can go toward this project(i would rather not, if i don't have to). I will get some largish PC boards for mounting the diodes to, and capacitors if i can find a bunch of cheap 22uf 400 volt caps or so.

The main thing i need to find is the Charging inductors. 30h would be good, as long as it can withstand such high voltage(10kv from the power supply, and then any spikes).

Arcstarter

Tue Dec 16 2008, 03:07AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Well, i got 2 new microwaves today, so that means two more transformers and diodes and caps :). One transformer is pretty big and it looks very good and new and clean, and the other one, well even i considered throwing it out. It was slightly rusted and dirty and stuff. So, i have the power transformer and the inductors. Now i just need to find the 22uf 400vdc caps (or two 1.5uf 6kvdc caps and 2 3uf 3kvdc caps) and that should be just about it. I do still need to buy the diodes, tank cap, bleeders for the multiplier cap, and the wire for the secondary, but all that is coming from ebay other than the wire, which will be double build from parawire.com.

Arcstarter

Tue Dec 23 2008, 05:03AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Well, i bought the diodes. It was 16USD in all for 1000 1n4007 1kv 1 amp diodes, sounds alright to me. Alright, so now i pretty much only need the tank cap, wire and doubler caps.

I have decided on the tank cap, but can someone PLEASE tell me were to find some doubler caps? I have looked on ebay, and did not find any 22uf caps, and there are no high voltage 3uf caps. I would like 6 3uf 3kv caps, or about 50 (would use 42) 22uf caps with at LEAST 400vdc, electrolytic.

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob