The transformer will probably be labled 50\60hz. Its fine to run a 50hz transformer at 60hz but going the other way, might pose problems. You need to look at your location to figure out what your wall frequency is. A quick google search of line frequency in country X, will probably prove enlightening.
Jim, is their more recent guidance with reguard to the mmc cap chart? I was under the assumption that the chart was decently well vetted by the community and sort of a go to standard. Is that still true?
Cheers, Jay
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------ Original message------From: p_novotny via Tesla Date: Wed, Jan 6, 2016 9:53 AMTo: Tesla Coil Mailing List;Cc: Subject:Re: [TCML] LTR Primary Cap on tesla coil
Ok so according to the chart and to your calculations below I'd be looking for .01uF or 10nF. I have a static spark gap. 15 of the 942C20P15k in series would get me exactly .01uF. I'll have to check to make sure the transformer is 60 hz when I get home. Thanks guys.Sent on the new Sprint Network from my Samsung Galaxy S®4-------- Original message --------From: jimlux Date: 01/06/2016 7:58 AM (GMT-06:00) To: tesla@xxxxxxxxxx Subject: Re: [TCML] LTR Primary Cap on tesla coil On 1/5/16 9:48 PM, Heather & Paul Novotny via Tesla wrote:> Hi, I have a 12,000 v 30ma NST for my power supply.>> Currently I am using a 5gal bucket cap filled with beer bottles and saltwater. It measures .01315uF on my multimeter. I am getting about 12-15" streamers off my toroid with this setup.>> I would like to try some Cornell Dubilier caps and am wondering what the LTR cap size would be for my power supply?60 or 50 Hz?"Resonant" is where the reactance of the capacitor is the same magnitude as the reactance of the transformer.The transformer reactance is simply E/I or 12,000/0.030 = 400k (technically, it's j400k, because it's an inductor)The reactance of a capacitor is 1/(j*2*pi*frequency * C), where j is sqrt(-1). Typically, you'd see the reactance as -1/(j*omega*C) where omega =2*pi*frequency.what you want is to rearrange this a bit..400k = 1/(omega*C) --> C = 1/(omega*400k)for 60 Hz omega = 377, so C = 1/(377*400k) = 6.6 nFSo this is the resonant size (one you actually want to avoid)...You want Larger Than Resonant (LTR) ... typically 1.5-1.7 x the resonant size, which works out to 10-12 nF.If you're using the usual 2kV, 0.15 uF caps, 12 of them in series gets you there-> 12.5 nF @ 24kV or you could use 1600V caps.. that's 19.2 kV, or 13 in series gives you 20.8 kV and 11.5 nFwith a 15 kV transformer, the peak voltage is 1.414*15= 21.21 kV.>> I saw a formula for it but I don't know what all of the variable names mean in the formula.>> Can someone please help me with this?>> Thanks - Paul> _______________________________________________> Tesla mailing list> Tesla@xxxxxxxxxx> http://www.pupman.com/mailman/listinfo/tesla_______________________________________________Tesla mailing listTesla@pupman.comhttp://www.pupman.com/mailman/listinfo/tesla_______________________________________________Tesla mailing listTesla@pupman.comhttp://www.pupman.com/mailman/listinfo/tesla
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