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Re: Dan's coil (was no subject)

Hi Dan,

>
>Secondary Coil:
>
>The size of the secondary is based upon the size of my torroid.
>According to the TESLAC program, I need 1800 - 4000 watts to drive
>this properly.	This program assumes that I use a helix that is
>8" - 12" in diameter.  According to the TCBA article written by
>Richard Hull, that diameter is too big.  My thoughts are that I should
>use a 6" diameter form that is 15" in length.  Does this sound okay?
>
>Also, I have heard that gray PVC pipe is reasonable for a coil form...?
>

Dan, screw everything everyone says about diameter.  I have worked 1000watt 
coils very nicely on 12 inch diameter forms.  Now, the toroid is another 
matter.  If the cross-sectional area is too large, your output voltage may not 
be enough to break out.  This is simply remedied by attaching a smaller radius 
hump somewhere on the toroid to allow the discharge to break at that spot.

PVC is lossy and not recommended.

>Main Transformer:
>
>12KV -at- .12A is approximately 1440 Watts.  According to the TESLAC
>program this is not enough power for the secondary and torroid.  The
>transformer is sunk in oil.  I think I can push the power rating of the
>transformer to at least double for Tesla Coil operation.  If I capacitively
>load the transformer to double it's rating, will this work? Or will the
>transformer core saturate and not give better performance?
>
Is the transformer self-limiting?  If not, you can probably coax at least 
another 20-40% out of it.

>.025uf CAP:
>
>This is a DC cap.  Will this work okay in this type of a system?  Also,
>The reactance of the cap should load the 12KV transformer to around .1A
>at 60 cycles, if I do not add additional capacity will this amount of
>power drive the secondary system as stated above?
>
It will drive it just fine.
What is the dielectric material of the cap?  If this is a typical oil type 
capacitor or one used for power factor correction, it is ill suited for Tesla 
coil use and may even EXPLODE!  Capacitors should be of polypropylene or 
polyethylene dielectric.  Mylar is OK in a pinch.

>Spark Gap:
>
>I am building an 8 pole stationary gap in a brass housing that will be
>air tight.  I want to quench the gap rapidly and am thinking about pulling
>a vacuum on the spark housing.  Will this work?  Should I be filling the
>housing with a "magic" gas, or pressurizing the housing?
>
Vacuum no, pressure yes, even just air or clean dry nitrogen.  Using a magic 
gas like sulphur hexafluoride works great if you can keep it constantly 
flowing and properly vented.  The various after-the-spark-has-done-its-thing 
fluorine by-products are VERY nasty.  Another good quenching gas is freon, 
another no-no.  Quenched gaps are typically made by just sealing the thing up 
and letting the spark burn all the burnables.  However, at the power level you 
are working at, a quenched gap is not all that important.

Good luck.
Zap,
Mark