[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TCML] Secondary Coil Form



Hi Jim,

Yes, I agree, the problem of how much moisture a scrap piece
may have absorbed lying in a mud puddle is likely the biggest
issue in this situation. As for my aforementioned Green Monster
form, this issue was successfully sidestepped by the fact that
I purchased it new and by the foot from a local plastic suppli-
er. A little pricey ($5 or $6/ft, I believe, around ~2003), but
worth the cost to get exactly what I needed and to pretty much
avert the absorbed moisture problem.

David

----- Original Message ----- From: "Jim Lux" <jimlux@xxxxxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Thursday, September 13, 2012 5:46 PM
Subject: Re: [TCML] Secondary Coil Form


On 9/13/12 7:24 AM, David Rieben wrote:
I suppose there always is some risk of obtaining PVC with conductive trash in it, since the industry specs don't require pristinely pure materials for the intended application. However, It seems from the collective data from fellow coilers that the actual level of risk of electrical failure is quite small and manageable. I, for one, have never had any issue with the PVC piping material that I have used in all of my TC forms over about 20 years of actual coiling. As a matter of fact, until I "knew better", I never even bothered cleaning off the printed lettering from the surface of the pipe before winding it. I am currently using gray 12" PVC duct pipe (thinner walls than sch. 40) for the sec. form of my Green Monster coil and it's been performing *pretty much flawlessly for about 8 years now. (I did have one flashover that damaged it and caused me to have to facilitate repairs, but I attributed this more to not wiping down its surface from dust or possible moisture after i
t sitting
idle for months than to any conductive impurities in the PVC material.) I noticed that Ed Wingate would wipe down the extra coil of his huge maggie before firing her off and I've since employed a "pre-fire" wipe down as normal setup for firing off my coil now. So far, I've had no more secondary failure since doing this.

David


I would agree with you that it's not a big risk.. a bigger problem is the water that might have been absorbed when that big piece of pipe was sitting in a puddle.

Even bigger surprise is foam core that looks solid (e.g. ABS DWV..the "foam" has such tiny bubbles you can't see them except with magnification).

But even in that case, the voltage stress along the secondary isn't huge. Figure 400kV or so spread over 2 ft. that's <20kV/inch.

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla