TCML Guys -Remember that Terry's original R-C filter design used a total of 12 capacitors across the NST terminals - six from each bushing to ground. If one used Terry's original .0033uF/1600 Panasonic caps, the voltage rating for the whole string would be ~19Kv, not 38KV.
This already has a negative safety margin with a 15KV NST (21,210 volts peak-to-peak), but probably will "survive" if not subjected to voltages much higher than the NST peak.
Amir -You MOST DEFINITELY do NOT want to use a tank capacitor value that is resonant with your NST. This is almost a guaranteed to (sooner or later) result in an NST and/or tank cap failure. For your static-gap coil, you need to select a tank cap value that is "larger than resonant" ("LTR") for your NST. LTR will typically be 1.3-1.6 times the "resonant" value.
If you don't know about the dangers of a resonant tank cap value, and why they can cause the voltage in the primary circuit to "ring up" to extremely high values, you need to spend some time on Richie Burnett's excellent website (http://www.richieburnett.co.uk/tesla.shtml), where all this is clearly explained in great detail.
Also, it sounds like the safety gaps in your Terry filter were not adjusted correctly, as they should have begun firing before the point where your capacitors "caught fire".
The TCML archives contain a wealth of information on LTR tank capacitors, adjustment procedures for safety gaps.
Regards, Scott Hanson----- Original Message ----- From: <Ln2guy42@xxxxxxx>
To: <tesla@xxxxxxxxxx> Sent: Tuesday, February 05, 2008 8:37 PM Subject: [TCML] My terry filter capacitors blew up!!
Hello all, Recently I built an MMC for my medium sized 4.5 inch diameter Tesla coil,and the total value for it is .0053uf at around 35,000 volts. This is resonantfor my Magnetek 15kv 30ma NST.I had a Terry filter on the NST, (i bought the kit off ebay) and when I ran the coil, the capacitors on the Terry filter blew up and caught fire. I was wondering why this is, and also I need to know how I can replace the caps.Do they need to be the exact same kind of capacitors? The ones that blew were .0033uf at 1600v each. There were 12 capacitors in series.I was wondering if I could use these other caps I had which are 0.015uf eachat 1600v. I have around 20 of those. Would the extra capacitance make a difference? How does the capacitance affect the Filter and in general the whole Tesla Coil? Sorry if I seem naive to this, but I'm only 14 years old. I really appreciate this a lot!!!! Thanks, Amir M. **************Biggest Grammy Award surprises of all time on AOL Music. (http://music.aol.com/grammys/pictures/never-won-a-grammy?NCID=aolcmp003000000025 48) _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
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