Re: [TCML] Big VTTC Suggestions Wanted

["Phillip Slawinski" <pslawinski@xxxxxxxxx>]

James,

Very nice coil you have there.  The video you made is great.  I have a few
questions regarding your setup.  I noticed that you wound your form with 30
AWG, was there a reason for using such fine wire?  I thought VTTCs preferred
to be run at higher frequencies. Using such fine wire certianly would lower
your resonant frequency substantially.  I also noticed you are using a 10AWG
primary, does this not get extremely hot?  Even on my small MOT driven VTTC
I had problems with primary heating.  I started out using 12 AWG wire and I
melted the insulation to the point where turns started to fuse together.
What was more disturbing is that it only took a  few minutes or so of
operation to get the wire that hot.  I now have my primary wound with 8AWG
and that will still get slightly warm after a long run.  Have you tried this
coil in stacatto mode?

-Phillip

On Thu, Oct 2, 2008 at 11:04 AM, James <mustang3@xxxxxxx> wrote:

> Hi Phillip, You will get better results with 1 large toob rather than a
> gaggle of smaller ones. You also need a low Mu tube. Normally tubes
> designed for grounded-grid, have higher Mu. I have a 3CX3000F7 tube in
> my big VTTC. It has a Mu of 5. You are required to drive it with lots of
> power. Lots of power means great sparks, interesting failures, fine
> memorys. I use a 7.2KV@5KW pole xmfr. I draw around 80A at full
> power(variac set to 280V). I also use a full-wave bridge to rectify the
> pole xmfr. I think the spark has more pazzaz with 120Hz on the plate.
> The VTTC will melt a piece of #10 copper in 30 seconds. Molten cooper
> drips off and lands in the torrid. I have also tried it in
> self-rectifying mode (put AC onto plate; tube only conducts on positive
> occicle). Sounds mean on 60Hz; doesn't have as much presence. Here's a
> low resolution clip of it in operation. Later, James
> http://www.youtube.com/watch?v=7Ky4a9KPlVY
>
> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of Phillip Slawinski
> Sent: Thursday, October 02, 2008 7:58 AM
> To: Tesla Coil Mailing List
> Subject: [TCML] Big VTTC Suggestions Wanted
>
> Hi All,
>
> I'd like to build a large VTTC.  I'll probably end up going with a 6"
> secondary since I have 6" PVC already.  I can get my hands on 7200V PT
> to
> use for the tank power supply.
>
> What kind of K value should I be aiming for?  Is there any reason why I
> would not want to use a larger triode instead of multiple 833Cs?
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