Re: [TCML] ANother tube coil question

[drieben@xxxxxxxxxxx (David Rieben)]

Hi John,

Thanks for your response. We both saw Ed Wingate's 
big tube coil just a few weeks ago ;^) I do recall him
mentioning the Litz wire primary, now that you mention
it. Isn't Litz wire very expen$ive, though? It doesn't seem
to show up that often on eBay. I can only imagine how 
much 50 ft. of #8 Litz wire would set my wallet back! 

--
David Rieben

-------------- Original message -------------- 
From: futuret@xxxxxxx 

> 
> David, 
> 
> Yes VTTC primaries tend to run hot. Ed Wingate now 
> uses litz wire on his primary, and he said it runs 
> a lot cooler after making the change to litz. 
> 
> I usually use 12awg solid or stranded wire for 
> sparks up to 36" long. I don't keep my runs all 
> that long, so it works OK. It's a good idea to 
> measure the input power and compare that 
> to the obtained output spark length. It should 
> take about 2400 watts to obtain 24" sparks. 
> 
> I use the formula: 
> 
> spark length (inches) = 0.5*sqrt input power (watts) 
> 
> for VTTCs 
> 
> Cheers, 
> John 
> ---------------- 
> 
> -----Original Message----- 
> From: David Rieben 
> To: Tesla list 
> Sent: Wed, 10 Sep 2008 10:27 pm 
> Subject: [TCML] ANother tube coil question 
> 
> 
> 
> Hi all, 
> 
> I have been having a bit of trouble lately getting my 
> VTTC back up and staying running. I flashed over the 
> primary to the secondary coil yesterday and damaged 
> the secondary enough that I am just going to have to 
> wind another one. I tried to rewind with #22 wire that 
> I already had laying around on a longer form but it still 
> turned up being WAY out of tune as the original se- 
> condary was about #26 or possibly #28. I tried winding 
> some old #28 or possibly #30 from an old secondary 
> bobbing from a dismantled x-ray transformer, but it was 
> unusable for rewinding as it had a bunch of glue and 
> kraft paper stuck to the wire which caused it to wind 
> poorly and to snag and break easily. So it looks like I'll 
> be having to either buy some more #28 magnet wire or 
> else just buy a prewound secondary coil of the same 
> approximate demensions and wire guage, as they ap- 
> pear fairly plentiful on eBay. 
> 
> Now my question is do you other vacuum tube coilers 
> have trouble with your primary coils getting really hot 
> after just a minute or two of operation? I was originally 
> using #10 for my primary but it was getting practically 
> smoking hot and I ended up replacing it with #6. The 
> #6 still gets quite warm after a minute or so of firing, 
> especially in continuous mode. I'm wondering if it's 
> more inductive heating going on here than resistive 
> heating as the leads to the primary coil are of the 
> ame guage but don't seem to get near as hot. 
> My VTTC is ran off of (2) sereised MOTs into a 
> level shifter and an 833 tube with 8 uFd of filter caps 
> in the shifter and 5 nFd in the primary tank cap. 
> 
> Thanks, 
> David 
> 
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