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Arcstarter

Fri Apr 04 2008, 06:52PM

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

Were can i get some good capacitors for a tesla coil? I have already ordered some and they worked perfectly(for about 4 minutes of run time)! I want to use them at 4kv and 8kv and 6kv. All these voltages will be used because i am going to use 6kv nst,two mots,and two mots with doubler for a dc resonant charging circuit. I am too poor to get the "proven" cornell dubilier capacitors. I guess i will need a rating upwards of 12kv? I would like it to be a mmc so if one capacitor fails no big deal. Just replace it. I have seen some link on this forum that had some capacitors like out of a T.V. (you know,the film capacitors) for like 2 bucks a piece. How about these?

I would need 12 for 18.6nf which be 19kv which would be perfect for the nst and good for resonant charging with a rsg. Any ideas?

And would the transparency capacitor work well with a tesla coil and were can you find the transparencies?

Ultra7

Fri Apr 04 2008, 07:20PM

Registered Member #1157 Joined: Thu Dec 06 2007, 12:11PM
Location: Houston, TX
Posts: 307

I say give em a try.
They don't seem to be on either the good or bad list.

If they work okay, let me know, I'll get some as well.
If they don't, I guess we can add them to the bad list.

Dr. Dark Current

Fri Apr 04 2008, 07:35PM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

I'm sorry but I had bad experience with these "red" caps, they heat much more than similarly rated MKP cap. But of course not all red caps could be bad.

Arcstarter

Fri Apr 04 2008, 08:38PM

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

Ultra7 wrote ...

I say give em a try.
They don't seem to be on either the good or bad list.

If they work okay, let me know, I'll get some as well.
If they don't, I guess we can add them to the bad list.

Well i will but it will take me about a week or two to get the money because to get money i have to mow yards :(.

Ken M.

Fri Apr 04 2008, 09:34PM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

I have fresh red caps and the oly problems I've ever had, is when the Primary of my Mini coil has a high inductive kickback and the caps are really close to the fes then the legs of the caps arc to the fets, or I get a ridiculously chatostrofic fail of parts and a cap explodes, but thats only happend once.

Ultra7

Fri Apr 04 2008, 10:54PM

Registered Member #1157 Joined: Thu Dec 06 2007, 12:11PM
Location: Houston, TX
Posts: 307

Arcstarter wrote ...

Well i will but it will take me about a week or two to get the money because to get money i have to mow yards :(.

EEEEK!!!

I remember those days!
Nowadays I just have to balance the budget with: "Do I want to eat hot dogs for 2 weeks, or should I buy some Capacitors?"

Arcstarter

Sat Apr 05 2008, 02:50AM

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

Yea well in one day i got 55 bucks and i have every thing for a sstc but a 200k ohm pot,.33uf cap and then i just experiment with different shunt caps and inductance on primary :).

Sorry that was sort of off subject.

flannelhead

Sat Apr 05 2008, 06:57AM

Registered Member #952 Joined: Mon Aug 13 2007, 11:07AM
Location: Finland
Posts: 388

If you are on low budget, try making your own.

That doesn't really cost a lot and if you make them nicely enough they can be almost as good as commercial caps.

I made two of them using some slices of plastic bags instead of transparencies. It took about 5 minutes, and I was amazed they worked! Not too well, though, but if you spend a little more time making them nicely it really should be worth it!

Arcstarter

Sat Apr 05 2008, 04:43PM

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

Well tdu has made some crazy caps using Pe(polyethylene). Were can i find these polyethylene sheets? I have made my own caps before with mylar sheets. They work excellent but i didn't put them under oil so the corona ate away at it until it fail while operating my tesla coil. For more info on how i made the see here:

bob golding

Sun Apr 06 2008, 02:28PM

Registered Member #1084 Joined: Mon Oct 29 2007, 08:58PM
Location:
Posts: 28

when i made my own caps i used those poly pockets used for protecting sheets of A4 paper. I used old alumimiun litho plates from a company that recycled them from printers. i put the completed cap in a pedal bin and filled with transformer oil. it did work, worked out at around 12nF 15kv. would i do it again? well no to be honest but this was before mmc's so there wasn't a lot of choice at the time. there is a pic of me holding it here. half way down the page.

It was a labour of love but i ditched it as soon as mmc's came along.

bob golding

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