Another thread about tesla coil capacitors. / Tesla Coils / Forums

Forums

4hv.org :: Forums :: Tesla Coils

« Previous topic | Next topic »

Another thread about tesla coil capacitors.

Move Thread

LAN_403

Arcstarter

Fri May 16 2008, 08:06PM

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

Ok, I have a 12kv 60ma nst, and i need capacitors for it. I need 20kv at 18-20nf. I have tried using the transparency capacitors and i cannot find any freaking polyethylene to roll my own capacitors. Can anyone direct me towards a capacitor that is cheap but good quality? All i will have for next 2 weeks is 60-80 bucks. Thanks ahead of time.

RogerInOhio

Sat May 17 2008, 01:29PM

Registered Member #1034 Joined: Sat Sept 29 2007, 12:50PM
Location: Chillicothe, Ohio
Posts: 154

You might want to try a local hamfest. You might get lucky.

Roger

Hazmatt_(The Underdog)

Sat May 17 2008, 05:37PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

You'll actually need a cap rated for at least 24kvac rms, which would be ~35kvdc rated at 100% reversal, so you need to be careful about your AC and DC ratings, that is if you want it to be nearly indestructible. Several people are finding that they have no problem running at lower voltage ratings, it just means the dielectric suffers more heating and possible puncture during charging/discharging.
If you wanted to be safe, I'd say 35kvdc rated Maxwell, but again they have a life expectancy so a used one may have 1000 shots left, it may have 10 left, can't really tell by the outside.
Hamfest or electronics swapmeet would be good, hunting for parts is half the fun! ^^

Arcstarter

Sat May 17 2008, 09:11PM

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

If finding the parts is half the fun, i don't wanna do coils anymore

. Where can i find a hamfest close to beaumont texas? I am only 14, would they let me in? And i cannot go far because my mom would not take me far..... Man, i am really out of luck

UPDATE: I just found these capacitors. They are affordable and have a value that i have been dreaming about.

Would they stand up?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?! ?!

O.k. Another UPDATE!: I would like to know were i can buy some cheap polyethylene or can someone roll a 35kv 18-20 nf capacitor for me? I will pay!

Hazmatt_(The Underdog)

Mon May 19 2008, 05:46PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

I don't want to sound mean or anything, but SGTC's get very expensive when you factor in the capacitor, so you may want to just ditch the idea and go for a solid state coil insted. I also don't know what you've heard about SGTC's, but it can take years to obtain all of your parts if on a budget. It's taken me probably 5 years to get the capacitors together to form any sizable bank, and up until recently I had no large variacs for power control. You sorta have to be in the right place at the right time to get your building materials.
If you don't plan on spending a couple hundred dollars on the cap, you'd be better off going solid state I think.

Quantum Singularity

Mon May 19 2008, 06:24PM

Registered Member #158 Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282

It all just depends. My first [few] tesla coils I put together (sg's) for under $50 I bet. I even got some cheapie doorknob caps donated since I was in college at the time and I was going to use it for a class project. On a later variation I bought similar doorknobs for like $15-20 a piece (x3) as I recall from Dr. Resonance about 10 years ago. They worked fine for 2-3' long arcs from a 12kV 60mA nst. But do check out hamfests, you never know what you may find. One year I found a .04uF 40kV pulse cap at the Dayton Hamfest. Year before that I got two big ol' 6kJ Maxwel Energy Discharge Caps, and wish like heck I'd have had money for the third one they had. Good luck, and remember, beggars can't be choosers

Arcstarter

Mon May 19 2008, 08:02PM

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

But would those caps stand up? I have already made a sstc, of my own design, and it actually worked fairly decent too. But there is nothing better than a roaring spark gap and numerous foot arcs and being really inefficient. I really want to finish this coil because i spent 78 bucks on the nst! I also spent over 40 bucks for the wire. I know i can get a capacitor for under what i should have soon. All i need to do is go to southerlands and they may have the polypropylene sheets i have been wanting so bad. Not only that, but i can just my a few sheets of mylar and make a cap out of that and put it under transformer oil so it will not die so quick. I started this thread because i would rather use materials others have used with success , or find a good cap bank... Like that coil on youtube, i bet i would have to use tons of capacitors for a decent sized cap bank. They used over 100 wima capacitors.

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