Re: Coil Specs

[Terry Fritz <twftesla-at-uswest-dot-net>]

Hi Sam,

At 01:12 PM 8/28/00 -0500, you wrote:
>	Hello,
>
>	Here are the specs for my first coil:
>
>	Line Xfmr: 15KV/30mA Franceformer (NST)
>		Power: 450VA
>	Capacitor: LTR MMC-Approx. 0.0075 microfarads -at- 42,000VDC

You don't need to make the MMC voltage so high.  20kV is fine for MMCs.
Unlike rolled poly caps, MMCs can be made to the actual voltage rather than
3X.  MMC caps can take over voltage hits and recover just fine unlike other
types of caps.

>	Primary coil: Helical-5.5 turns 1/4 inch copper tubing, 1/4 inch
>spacing
>		Height: 3 inches, 3.5 inches to top of arc ring, spaced
>approximately 1/2 inch 				inside the primary
>		Diameter: 12 inches
>		Primary inductance (max): 15.43 microhenries
>		Primary resonant frequency (min): 556.8KHz
>	Secondary Coil: 696 turns of 26 gauge wire on a 3 inch diameter form
>		Height: Windings: 12 inches, overall: 14.5 inches (0.5
>inches on the bottom, before windings, 2 inches after the windings)
>		Secondary inductance: 8164.31 microhenries
>		Self-capacitance: ???

About 6pF.

>		Topload: 4 inch OD, 1 inch cross-section toroid
>			Capacitance: 4.418 picofarads
>		Secondary resonant frequency (max): 861.97KHz

That will come way down with the self capacitance.

>	Spark gap: Richard Quick style gap-3 gaps
>		Firing voltage (input to Xfmr): 110V
>
>	No safety gap yet, and I won't put in chokes.  Feedback?  Anything
>I need to change?

Be sure to always use safety gaps.

Cheers,

	Terry


>
>	Sam Beck
>
>