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LAN_403

Fraggle

Sat Jul 12 2008, 09:26PM

Registered Member #1526 Joined: Mon Jun 09 2008, 12:56AM
Location: UK
Posts: 216

Hello, I have a secondary with many black strike burns on the outside and they`re causing a lot of breakout, although it still performs quite well. Fortunately there is no tracking on the inside and I thought I might just dump the whole thing in oil and keep using it, maybe it would even work better.

Does anyone see a problem with this?

Will

J. Aaron Holmes

Sat Jul 12 2008, 09:59PM

Registered Member #477 Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546

Hi Will:

Several people have built oil-immersed secondaries and they work fine. I'm working (slowly) on one myself.

I expect, however, that the breakout is less a function of the strike marks than of one or more of the following:
1) overcoupling
2) too much power
3) incorrect tuning
4) improper topload dimensions/size relative to secondary
5) topload raised too high above secondary
6) secondary H:D ratio too high

Pictures and/or descriptions of the coil might help.

Cheers,
Aaron, N7OE

Fraggle

Sat Jul 12 2008, 11:26PM

Registered Member #1526 Joined: Mon Jun 09 2008, 12:56AM
Location: UK
Posts: 216

The toroid was raised 4" above the secondary but I learned that lesson and cut it down. I have played with the coupling as you suggest but no joy.

The coil is pictured second most recent in the sticky thread but the toroid is now only 1" above the coil and there is a strike rail. The power supply is now 3 MOTs not 2 as described in the thread.

I am using far too much power I think, sometimes it pops my 13A breaker (@240V) and it`s only 4" in diameter! If I add more ballast the problem is gone but that`s no fun - I`m interested to see how far I can push it and I`m already well in to winding another anyhow :o)

I would be very pleased to hear opinions on the relative dimensions of the coil/toroid and the H:D ratio.

Thanks for replying :o)

Will

Fraggle

Tue Jul 15 2008, 10:14PM

Registered Member #1526 Joined: Mon Jun 09 2008, 12:56AM
Location: UK
Posts: 216

Here we are, working pretty well so far.

Coronafix

Tue Jul 15 2008, 11:28PM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

What is the distance between your innermost primary turn and secondary?
It looks to be pretty close. You could try raising the secondary as suggested, but
you say you've has no luck with that. What about cutting out the innermost turn of
the primary? You should have a clearance of at least 25.4mm

Ultra7

Wed Jul 16 2008, 01:09AM

Registered Member #1157 Joined: Thu Dec 06 2007, 12:11PM
Location: Houston, TX
Posts: 307

I bet that coil running in the living room like that gets rid of any cigar smoke with all the ozone that bad boy produces.

I got a book by "the Man" himself where he pretty much describes his whole coil as being immersed.
Here it is =>

I want to build his version of the coil one day, using all the same materials he used, and do all the experiments he did. Not that this really has too much to do with your issue, you've got sparks and what not. I think Dr. Hankenstein wrote an article on that, lemme see if I can find it.

here ya go. He was having basically the same issues you were having.

Fraggle

Wed Jul 16 2008, 01:29AM

Registered Member #1526 Joined: Mon Jun 09 2008, 12:56AM
Location: UK
Posts: 216

Well, the French doors are open next to it so it`s practically outside really.

The picture is a bit dark to see (I`ll swap it for a different one) but the secondary is now in oil and working great, I have it very tightly coupled and no strikes or sparks through the oil at all. The clearance between primary and secondary is ~10mm (of oil).

I think I need a smoother strike rail as there is a permanent `pedestal` of corona between it and the toroid but I reckon I`ve got headroom for even more power now :o)

Maybe I`ll plonk another MOT in series.

Fraggle

Sat Jul 26 2008, 10:05PM

Registered Member #1526 Joined: Mon Jun 09 2008, 12:56AM
Location: UK
Posts: 216

Hey all, my coil has evolved considerably.

New specs:

Quad MOT supply with a fifth for ballast, outer pair under oil with cores floated.
24nF MMC.
Second toroid stacked on top.
Strike rail removed to avoid corona loss (no problems with strikes now anyways).

My best strike is well over 4`, nearly three times the length of the secondary which I think is not too bad at all. My next step is a new spark gap and a helical primary (also under oil) for ludicrous coupling. Pics to follow tomorrow.

Coronafix

Sun Jul 27 2008, 02:01AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

That sounds awesome! Look forward the pics.

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