Re: Terry's latest gap (fwd)
---------- Forwarded message ----------
Date: Sun, 26 Jul 1998 23:38:11 -0600
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Terry's latest gap (fwd)
At 08:52 PM 7/26/98 -0600, you wrote:
>From: Mark Finnis <mefinnis-at-medicine.adelaide.edu.au>
>To: Tesla List <tesla-at-pupman-dot-com>
>Subject: Re: Terry's latest gap (fwd)
>At 09:42 PM 24/07/98 -0600, Terry wrote:
>I have built a couple of gaps just recently. First stoped working
>properly, so built one along the lines of Terry's. (30 gaps of 0.25 mm =
>10 mil). Worked really well initially. Did get quite hot, so placed my
>trusty fan nearby. All OK.
I think with 5 mil gaps the power dissipation is cut in half (twice the
copper). I don't know that for sure but It does seem resonable from what I
have seen. Is it possible you were not getting first notch quenching? This
would add much to the thermal load. If the quench is bad, much of the
systems's energy can go dirrectly into gap heating. A small fan should
increase the power dissipation many times as you have found. I think really
small gaps help keep the thing cool. Larger gaps seem to run much hotter.
I have gaps at 25, 7, and 4 mil. The 4 mil is the coolest running.
>But then ........ set fire to wood base, as had placed rows of tubing too
>close together, and while the distance was > 2x the summed gaps for the
>desired path, still got flames :-(
I live in a very dry climate and wood is a good insulator. Perhaps plastic
would be a better choice for most. I would like to try glass but I worry
that even small heating my break it.
>I suspect this relates to the field concentration at the ends of the tubes
>..... so in the interests of others not making the same errors as me. If
>you make a TFG ( I figure since we have RQG's, we may as well imortalize
>Terry as well !) , make sure the spacing between rows of tubing is
>Next. My gaps are 2.5 x greater than Terry's and the performance of my gap
>steadily declined with use. On inspection, there was BRIDGING
>carbon/copper oxide in many of the gaps. While this did not form a short
>circuit, it no doubt does decrement the quenching ability of the gap.
I was using my gap all afternoon. The gaps do have a light dark gray dusty
coating but the gap are still quite clear. I know that if you clean the
gaps when they get coated the quenching improves but I haven't been worrying
about it. It would be neat to enclose the gap in some inert gas (maybe with
a fan inside) this should stop the oxidation of the copper. I would check
the quenching first. That may be the problem.
>Anyone with similar experience ?? (especially Terry ??)
>In active support of the ozone layer ;-)
>Mark Finnis Hm: 61 8 8289 5205
>Consultant, Intensive Care Unit Wk: 61 8 8222 5042
>Royal Adelaide Hospital Fax: 61 8 8223 6340
>Adelaide SA 5000, Australia Mbl: 041 2324268