RE: [TCML] Re: Spark gap Resistance

["Terry Oxandale" <Toxandale@xxxxxxx>]

Is that a loss, or power passing through the coil circuit?

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
Behalf Of David Rieben
Sent: Wednesday, December 05, 2007 12:42 PM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Re: Spark gap Resistance 

Hi Greg, all,

Maybe I'm missing something here. 4200 amps (peak) across
0.65 ohms translates to 11.466 MEGAwatts peak power loss!
I know the SG is the culprit for the biggest waste of power in
the primary circuit (the heat associated with the SG electrodes 
and their associated mounting hardware verifies a significant 
power loss) but this seems like a rather large sum of 
lost power, even for peak levels.? Even with the really low
0.005 ohms for the silicon switch there would still be over 100kW
peak power loss at 4500 amps peak. I'm not that great on the higher 
math but this seems to suggest that with an assumed 80% effeciency,
the primary circuit's peak power must be on the order of >50 
MW? I suppose with the size of coils that Greg builds, 50
MW isn't that unthinkable for peak power levels, though.

David Rieben

-------------- Original message -------------- 
From: Greg Leyh <lod@xxxxxxxxxxx> 

> Hi Dave, 
> 
> Measuring across the rotary gap using a compensated divider and a CT,
I 
> found the effective impedance of the gap to be about 0.65ohm at 
> 4200A[pk.] This was on the 120L50K coil, before I reconfigured the 
> primary circuit for a higher Zchar. The voltage drop waveform showed 
> some non-linearity, as one might expect. 
> 
> Here's a desc of the 120L coil: 
> http://www.lod.org/Projects/120L50K/120L50K.html 
> 
> By comparison, the 4500V silicon switches in the 90L10K prototype
coils 
> exhibit an effective impedance of about 0.005ohm, at 4350A[pk.] GL 
> 
> 
> 
> > David N. Van Doren wrote: 
> > 
> > Does anyone have any data on spark gap resistance? 
> > and for that matter Streamer impedance? 
> > I've been doing some simulations, and for the lack of any better
number I've 
> been using 4 ohms for spark gap R's and have tried using
220kohm+1.5pf'/ft for 
> streamers, but doesn't always seem to look right in the sims. Trying
to 
> characterize plasma is always difficult at best. 
> > 
> > Thanks 
> > 
> > Dave 
> > 
> 
> 
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