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Re: Wire Guage and Q?

Hi Nathan,

At 09:03 AM 01/01/2000 -0800, you wrote:
>Greetings, All!
>
>     I am wondering about Q and how it relates to wire guage.  My present 
>coil seems to be getting rather poor output.  I have a 15/30 NST power 
>supply (I kicked it up to 60 mA a couple times because I do have a bunch of 
>other trannies) but my dad won't let me pump more raw wattage in until I max 
>out the coil at its present spec.
>
>I have a 0.005 uF cap that's polyethylene sheeting, and I just moved to a 
>rotary gap that is now synchronous at 120 BPS.  I am pretty sure it's sync 
>now that I modified it because the lights turn off when I run it until the 
>demand controller catches up.
>
>Anyway, straight to the point.  My secondary is on 7" dia T-600 PVC pipe and 
>24.5 inches of it are wrapped with 20 AWG wire.  Most of the coils I have 
>seen comparable to my size are wound with at least 22 guage, some even up to 
>25.  How exactly does Q come into play? I originally wrapped the secondary 
>with 20 guage because I read bigger guages get higher Q but also higher 
>isotropic capacitance.

This secondary should be fine.  "I" don't think Q makes that much
difference (IMHO).

>
>My primary is 15 turns of 1/4" refrigeration tubing at a 35.5 degree angle 
>spaced 1/2".  I think my secondary operates at about 300 kHz and I thought 
>with higher Q, precise tuning is required, but I can't see much difference 
>in output between the 13th and 15th turns on the primary.

Hmmmm...  something seems wrong.  Your primary is tuned to around 300 kHz
but your secondary coil will have a MAXIMUM frequency of 300kHz BEFORE you
add the top terminal...  You don't say what your top terminal is or exactly
how long your arc are but it sounds like the tuning is messed up a little
bit.  This should not be hard to fix because you are very close...

I would add more primary capacitance.  Since you have a nice sync rotary I
would raise the primary cap value to around 14nF.  That will instantly give
your three times the input power from your 30 mA transformer.  If your run
60mA you can go to 28nF (note that the optimum value is proportional of NST
current rating).  This higher cap value will automatically bring your coil
into the proper tuning range too.  If we know what your top terminal is and
the inner diameter of your primary (I guessed 9 inches) then we could
pretty much tell you where the new tap point would be.

Right now you are running the risk of hurting the cap or transformer from
resonant rise too.  I assume you have safety gaps like we always tell
everybody.  If you go to 14nF you will me much less like to pop something
due to over voltage.

>
>If I made a new secondary with finer wire (23-25AWG) would my coil run 
>better?  I tried to run my specs through WinTesla as best I could, but you 
>have to put in your desired output voltage first in the coil designer 
>instead of putting in your own specs and the program tells you what your 
>output should be.

Do you have the latest version of WinTesla?  I do not remember such a
problem...

>
>It told me for 200,000 V output voltage (which I think represents a foot of 
>output) with my present power supply and 15 primary turns that I needed 25 
>guage wire on the secondary.  Shoot! especially after all that work, AND 
>blowing $40 on a full 10 lb roll of 20 guage.  I may be able to trade that 
>roll and some money for a roll of 24 guage or so, but need I do this? have I 
>really maxed out my specs?

Don't worry, all your stuff is just fine.  You just need to bring it into
tune and play with the cap value.

>
>Thanks, and Happy New Year!
>Thank goodness Y2K didn't take down our beloved discussion list!

I spent $0.00 and 0 time preparing for Y2K and everything still works as I
knew it would.  I bet a few others wish they could say that right now ;-))
The local fireworks did wake me up at midnight...  Geezz! I thought it was
the end of the world! HAHAHA ;-))

Cheers,

	Terry

>
>Nathan Ball
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