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Re: Streamer length vs. power delivery time...

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Steve,

At 09:35 PM 6/18/2005, you wrote: 
Hi Terry,

I ran my coil tonight, posted results (including pictures) on its webpage:

http://www.stevehv.4hv.org/DRSSTC1.htm

I got 72" strikes with only 6 cycles!!  That should be 8.7J bang
energy or about 1044W at 120bps.  The MMC only got to about body temp
:-).

Anyway, the primary current was up to 700A with air streamers and
briefly tripped the 800A limiter during heavy ground strikes.  I will
play with the Rprimary in pspice to try to make my primary current
match up.  I found Rprimary to be extremely crucial to everything.

Also, there is NO energy left in the primary 1 cycle after the driver
is shut off (the current hits zero fast).  Pspice did NOT match this
with the 6p+220k streamer, in fact it took maybe another 6-7 cycles
before the current hit zero.  Something isnt right with the model
yet...


Ok,  We'll work on it ;-))

I did verify that ScanTesla and MicroSim give the same numbers:

http://drsstc.com/~terrell/modeling/ScanTesla-vs-MicroSim.pdf

Be "sure" to turn "Skip initial transient solution" off in the transient setup box by checking it.

http://hot-streamer.com/temp/MicroSim-Setting.gif

If you don't turn that darn thing off, it pre-charges everything in the MicroSim model before it runs... That was the problem I was having last night. As I suspected, MicroSim was wrong not ScanTesla ;-))

I think we need to look at getting a better idea of what Rp "really is" for a DRSSTC and maybe looking at what the driver looks like when it shuts off. Cload might also be like 1.5pF/foot too... Rsecondary might need some tweeks as well... The only way for Rpri to drop off really fast is if the driver is really sucking a lot of power back out. Maybe the model is not doing that well...

Beyond that, we will have to start looking into a dynamic streamer model as Gerry and all have mentioned.. But Iprimary should work regardless.... With your low cycle count, the streamer buildup effects are surely far greater that the long established streamer case the 1pF/foot+220k model was meant for.

It is cool that we can now get down to verifying these "old" models!! That "1pF/foot+220k" thing probably lasted far longer than it should have ;-)

Cheers,

        Terry



Steve

On 6/18/05, Tesla list <tesla@xxxxxxxxxx> wrote:
> Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi Steve,
>
> I am having a little trouble getting MicroSim and ScanTesla to agree about
> things this night...
>
> I "think" Rprimary should be about in the 0.5 ohm range for a DRSSTC. That
> is a pretty critical factor. We will have to really test it as time permits...
>
> So Let me work on it awhile and see if I can fix things...
>
> Cheers,
>
> Terry