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Re: Mark's DRSSTC II pictures

Original poster: "colin heath" <colin.heath4@xxxxxxxxxxxxx>

Steve said

You are using secondary feedback... and while Dan got his setup to
> work fine that way, ive always had problems and even pspice
> simulations suggest its not the right way to go as it never gives true
> zero-current switching.
I have used secondary feedback on 2 DRSSTC's now and had no problems with blown devices. However i must point out that i was running a half bridge, so much less power and also never really pushed it out to max with low inductance and high capacitance. i was running 5-6turns on a 7.5" primary with 100nF tank cap. If running much higher tank cap then obviously peak current climbs with bang energy.
I second Steves comments on field control as i have built many spark gap coils with no prob but the tight coupling and i assume higher rf radiation from the coil on a DRSSTC caused me no end of problems listed below. 1) Strike rail although cut as usual with pipe cutter for smooth edges i had repeated arc over to secondary(or from) when the power level climbed.
2) Primary clamp. I used to use alligator clips but on DRSSTC this was no good so went to a smooth clamp.
3) Without breakout point the above problems would be exagerated and also cause arcing all over garage from metal objects to ground(if they were not grounded) 

Hope this helps
Colin Heath
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Friday, December 09, 2005 2:23 AM
Subject: Re: Mark's DRSSTC II pictures



Original poster: "marc" <xp88@xxxxxxxxxxxxx>

Thanks to everyone who replied after looking at the pictures..
I learned a few good tips!

Marc


> [Original Message]
> From: Tesla list <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Date: 12/5/2005 9:36:41 AM
> Subject: Re: Mark's DRSSTC II pictures
>
> Original poster: Steve Ward <steve.ward@xxxxxxxxx>
>
> Hi Marc,
>
> I notice your bypass caps placed on your main filter caps, interesting
> idea... it was something i was thinking about doing when people began
> asking about primary strikes taking out the inverter.
>
> Some things that worry me:
>
> The clip on your strike ring has very sharp edges that point upward...
> forms a wonderful point for corona and possible arc-over.
>
> The primary taps also have sharp points... with couplings this high,
> field control is extremely crucial.  Ive gone through a lot just to
> keep sharp points to a minimum with my coils, i think you will see why
> when you fire that up.  You may need to use some plastic insulation to
> help eleviate the problem (this sometimes does work, but often makes
> things worse).
>
> You are using secondary feedback... and while Dan got his setup to
> work fine that way, ive always had problems and even pspice
> simulations suggest its not the right way to go as it never gives true
> zero-current switching.
>
> You will need a breakout point on that toroid (probably already knew
that).
>
> Coupling might be too tight, but that will be determined once you fire > it
up.
>
> Twist the wires of your GDT primaries together to lower the leakage
> inductance of that wiring.
>
> Aside from those small things, it looks nicely built.  I look forward
> to your results.
>
> Steve Ward
>
> On 12/4/05, Tesla list <tesla@xxxxxxxxxx> wrote:
>  > Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
>  >
>  > Hi Mark,
>  >
>  > I put the pictures up here:
>  >
>  > http://hot-streamer.com/temp/Mark/
>  >
>  > The coil looks great!!!
>  >
>  > Cheers,
>  >
>  >          Terry
>  >
>  >
>  >
>  > At 03:02 PM 12/4/2005, you wrote:
>  > >Hi Terry. The zip file is 3.6 meg. I don't know if this will come
through.
>  > >I hope so.
>  > >Thanks for looking at the pictures!!!!!
>  > >
>  > >Regards,
>  > >
>  > >Marc
>  > >
>  > >
>  > > > [Original Message]
>  > > > From: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
>  > > > To: <xp88@xxxxxxxxxxxxx>
>  > > > Cc: <tesla@xxxxxxxxxx>
>  > > > Date: 11/29/2005 8:39:17 PM
>  > > > Subject: Re: DRSSTC II
>  > > >
>  > > > Hi,
>  > > >
>  > > > You can send me the pics too and I can post them on a website so
>  > > > everyone can get too them.
>  > > >
>  > > > I powered mine up with like 6 x 9V batteries at first.  They had
the
>  > > > voltage but did not have enough current to blow stuff up if I
>  > > > goofed.  Then I could check all the gate drives and all before
>  > > > letting it rip at full power.
>  > > >
>  > > > Cheers,
>  > > >
>  > > >          Terry
>  > > > Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
>  > > >
>  > > >
>  > > > At 04:50 PM 11/29/2005, you wrote:
>  > > >
> > > > >Hi Dan, I bought your book about a year ago, and finally > completed 
>  > > > >the DRSSTC II. I think it came out pretty good. I was wondering
>  > > > >before I power up for the first time, would you mind looking at > a
>  > > > >bunch of close-up pix and give me your thoughts, opinions on
>  > > > >"first-light". I think I have everything needed, variac, 120-240
>  > > > >step-up, 8-foot ground rod driven in, etc.
>  > > > >
>  > > > >Where would I send or post pictures?
>  > > > >
>  > > > >Thanks
>  > > > >
>  > > > >Marc
>  > > > ><mailto:xp88@xxxxxxxxxxxxx>xp88@xxxxxxxxxxxxx
>  > > > >
>  > > > >
>  > >
>  > >
>  >
>  >
>  >
>