Re: MMC question

• To: tesla-at-pupman-dot-com
• Subject: Re: MMC question
• From: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
• Date: Fri, 11 Jun 1999 22:21:49 -0600
• Approved: twftesla-at-uswest-dot-net
• Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi Mike,

Comments interspersed.

> Original Poster: Michael Burton <mickb15-at-ozemail-dot-com.au>

> Here are the full specs of my ineficient coil. Once again, i'm looking
>for reasons I can only get 12" sparks from 1350 VA of input power.

IŽm getting 57"/63" from 1257VA, so I can understand your dilema.

> Primary:
> 16turns 3mm Iron fencing wire, Neatly wound with 7mm spacing at 30
>degrees.
> 2nF (sorry i said 20 last time, it was typo) rolled poly cap

Two things here:
1.) Iron (or any ferrous material) is VERY lossy at TC frequencies. IŽll
bet the wire gets pretty warm, right? Go for AWG 12-14 to experiment
and later switch to 1/4-3/8" Cu tubing.

2.) 15kv-at-90mA and 2nF doesnŽt match too well. Your giving away
energy here. With 2nF at 15kV you only have 0.225J. This wonŽt
get you far. Your spark length wouldnŽt change if you only used 1
NST in this case (as you noted below). You will need lots more
capacitance. For a good power factor compensate your NSTs
(this wonŽt result in longer sparks, but your circuit breaker will love
you for it).

> Secondary:
> 4.33" PVC. sanded, varnished, sanded, varnished.......
> 22" winding of 22 Guage wire.

This sounds okay.

> Grounding:
> either an electric fence ground pole 2' in ground, or a pile of metal
>rods not in the ground (results were the same using either)

I would try and improve this. 2ft of grounding rod is a little bit
"shabby". Try 3 or 4 poles a 3ft each.

Power supply:
> 3 X 15Kv 30mA NSTs (I used the "poor schoolboy doing science project"
> and scored 7 NSTs of which 6 worked, all in 1 afternoon).

Sounds great, too.

> No torroid yet.. I'm just using a bolt for now.

You NEED a toroid. The toroid will allow energy to build up,
once again resulting in longer sparks. A 4" x 30" toroid wonŽt
be too big for your coil. With the right cap and an even larger
toroid, you should get at least 45-50" sparks.

> Another interesting note is that it works almost as well using any one
>of the 3 NSTs as it does using 3, and i have tested that each work
>and are all in phase and well matched.

See my comments on cap size for this.

Coiler greets from germany,
Reinhard

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