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Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
No, you need a capacitor rated more than 7500V*1.41=10600V. For headroom and safety it should be 15000V minimum, preferrably more. (I suppose you're talking about building a Tesla coil?)
Registered Member #1214
Joined: Sat Jan 05 2008, 12:03AM
Location:
Posts: 3
ya thats why i posted on a tesla coil forum. lol. thanks for the help. is there any way to lower the voltage on the transformer or am i gonna have to buy a new one? or a new capacitor?
Registered Member #1127
Joined: Mon Nov 19 2007, 12:08AM
Location:
Posts: 139
CorbPeters wrote ...
i have a 7500 volt 20ma neon sign transformer and a 7000 volt high frequency capacitor. will this run ok? how can i use this capacitor?
It is critical that you do some investigation into Tesla Coils first before you start asking us these kinds of questions. Hey, we'll gladly help you... but meet us half way at least.
If you build a Tesla Coil with a capacitor that is rated ONLY for the supply voltage you will likely destroy the capacitor OR worse - blow the transformer. But you'll have to do some research to find out why that is the case. Look up terms - LTR capacitors -
I'll give you another hint: I'm building a 14.4 kV driven 6" Tesla Coil system - my capacitor is rated at .05 uF 46 kVDC. A capacitor this size should take voltage spikes to 18.5 - 19 kV AC. Tesla Coils see HUGE voltage peeks in the primary circuitry - so we need a safety rating. Also I'm likely only needing .035 -.04 uF because I'm only running 4 kW for power, but it doesn't hurt to have a little extra room in case I'm running a little more current.
Registered Member #1214
Joined: Sat Jan 05 2008, 12:03AM
Location:
Posts: 3
i also found a capacitor in a microwave that is 2100 vac 1.05uf can i connect this in series with the 7000 vac .04 uf capacitor and what values will this give me for my capacitors?
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
Forget all of that.
If you just want some really cheap sparks go with bottle caps.
If you want an MMC, save some money and buy these CDE942's are sold in smaller quantities by digikey and by ebay, but that's usually more expensive than a lot of 50 at rell.
I would strongly suggest you not to buy any other kind of caps apart from those. After some time you'll see that you actually saved lots of money by not buying useless capacitors (like I did).
You can expect only polypropylene film+foil caps to work well, nothing else. There are some other types (wima and vishay FKP caps) but those are usually hard tog et hold off.
Registered Member #105
Joined: Thu Feb 09 2006, 08:54PM
Location:
Posts: 408
From your questions, something tells me that you need to do a little more research before you build a Tesla Coil - Check out the HVWiki, as well as google for formula's regarding putting capacitors in series, and what this does to the voltage across each one, depending on values.
Registered Member #160
Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938
Here's what you do. Study the Tesla coil formulas (from link previously stated and understand how to use them. Playing with a Tesla coil design program really helps, Then with an understanding, you can work out what you have and what you can build with it. Cause as cool as Tesla coils are... they're really f... dangerous! So know what you're are doing first. I only say this because you're questions belie what you know.
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Capacitors
