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Re: Terry filter alternates?



Original poster: Esondrmn@xxxxxxx

Snip,

I use 3,000 ohm 25 watt resistors in series with each high voltage lead on my 3.0" coil with a 15 kv 60 ma transformer - and they do get hot. I use only these resistors and safety gaps for transformer protection. Haven't had any problems with this so far. Looking for some wood to knock on.

Ed Sonderman


In a message dated 12/7/04 6:25:01 PM Pacific Standard Time, tesla@xxxxxxxxxx writes:


Err, Except im not using 21kv, using 15kv, and they only will be charged to
7.5kv each, hence we get: 300pf and about 1watt at 120BPS
not sure where your math went wrong there, even at 21kv its only 7.938watts
at 120bps. + the 14.4 watts of his 120ma nst still not close to 29watts.
And im only operateing at 30ma, hence 0.9 watts disipated in the resistors.
Hence by the sound of it, for a 30ma 15kv coil, 5watt resistors could even
do in a pinch (assumeing the voltage did'nt expload them, hence why id
probley use 10 watt resistors, mabey 2 in series)


>So we now have 43.4 watts in the resistors. At 100 watts, they have a >300C temp rise. At 43 watts, they are cooking at 155C Darn toasty!! > >Problem is the normal full rated temp for the power resistors is stunning >300C!! So we massively over rate them to keep the temperatures sane. >Originally I used much smaller resistors, but everyone whined that they >were getting supper hot. So I upped the size of the resistors like 4X and >no more complaints ;-)) > >Cheers, > > Terry