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Re: Coupling constant for 4.25" secondary
My secondary is a 4.33" and my coupling coeff. is about 0.125 (estimated
from the oscilloscope pictures).
Anyway, eventually, the optimal coupling coeff. value depends only on the
value of the natural oscillating frequencies of primary and secondary
circuits. The key is the value of the so-called "tuning ratio" T.
You can learn about it e.g. in the paper that Terry posted a while ago:
tdes.zip - PCX scans- "Tesla Transformer Design and Application in
Insulator Testing" by Phung, Blackburn, Sheely, and James 1991
That is the coupling coeff. value that gives you the highest voltage
developed. Still nobody knows if your coil will stand it, the RSG will
quench fast enough, etc.
So your "optimal" value can be different from the one that gives you the
highest potential :)
tesla-at-pupman-dot-com on 13.03.99 19:01:33
To: tesla-at-pupman-dot-com
cc: (bcc: Marco Denicolai/MARTIS)
Subject: Coupling constant for 4.25" secondary
Original Poster: Gary Lau 12-Mar-1999 2058 <lau-at-hdecad.ENET.dec-dot-com>
<SNIP>
I've measures the coupling coefficient "k" two different ways with
identical results: 0.139. I just tried raising the primary up by 0.25"
and that changes it to 0.144, but it doesn't seem that the start of the
primary should be above the start of the secondary.
I know that there are so-called magic values of k that make for the
cleanest quench, the nearest one to my coil being 0.153.
What I would like to ask is, for other coilers using 4.25" secondaries,
what values of k have you achieved?
Gary Lau
Waltham, MA USA