Re: TESLA COIL REVISED

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi Paul,

At 12:28 AM 1/13/2004, you wrote:
>Hi Terry, All,
>
>Terry wrote:
> > [7Mhz PA] the designers may not have had the slightest idea what
> > they were doing....
>
>Could well be true, since it's my own homebrew.

:D


> > [silver plating] They tend to turn black in these days of sulfur
> > dioxide pollution :-p
>
>Not my field, but I believe the conductivity of the tarnished
>surface is almost as high as the original. Others will correct this,
>but I think that's the major benefit of silver plating.

Completely true!  The tarnish is silver sulfide that is actually very 
conductive!

>...........
>
>Terry wrote:
> > http://www.mksinst-dot-com/cgi-bin/product.exe?pid=MWH-100
>
>The commercial chaps must have got this stuff down to a fine
>art.  Dare I ask what the DC bias output is for?

The plasma tends to charge things with a negative bias and they can play 
with DC bias for fun effects.  I have had it all explained to me many 
times, but I never listened well.  One of the experts in such things works 
for me, so maybe I will ask and listen %;-))



>The L network in here is matching down from 50 ohms to a lower
>impedance, which makes sense with their plasma arc chamber.
>Although, getting the gap to fire in the first place could be
>quite exciting.

Certain impedances make striking easy.  The computer just tells it the 
sweet spot to got to to fire up the plasma.


> > http://advanced-energy-dot-com/Upload/wp_18_impedance_match3.pdf
>
>A nice summary of impedance matching issues.
>
>The coiler faces a tougher challenge than these commercial
>plasma applications because the discharge terminal is usually quite
>isolated from the other terminal and a very asymmetric discharge
>results - discharging 'into air'.  This must surely be less
>efficient, overall, as a way of generating volumes of plasma.

E is better than 90% in most cases.  They are air cooled to like 10kW.


>At least there are no striking difficulties with this mode :)

:-)))))


>I suppose that as the frequency is raised (for a given terminal
>and fixed load power) the discharge becomes shorter and hotter.
>But does its impedance go up or down?

I think down,  not sure...

Cheers,

         Terry