Re: More DRSSTC fun!

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Steve,

I see you coil is working well ;-))  Apparently you have not even blown 
anything up yet!!

For the corona, I assume the inner turn of you primary is directly from the 
H-bridge side (low voltage) or the primary circuit.  The high voltage 
(H-bridge drive side with the primary cap) is connected to the outside of 
the primary where the high voltage across Cp will do no harm and be far 
from the secondary coil.  You want the voltage between the primary and 
secondary area to be say 240 V not 10,000 volts.

It might be a tuning problem too....

You can always raise the secondary in any case.

Worst, it could be the driver circuit loosing sync or something.

Be interesting to see what the fix is, but it will probably be easy once 
you find it.  Hopefully, the latchup problem will disappear with the corona.

Cheers,

        Terry

At 04:32 PM 5/22/2005, you wrote:
> Hi all,
>
> I fired up the DRSSTC again today for some more fun!
>
> http://www.scopeboy.com/tesla/drsstc/firstlight/yeha-ouch.jpg
> (warning it's a big file 110kb)
>
> I was trying to provoke it into flashing over and latching up the driver 
> as it did before. This was running on the upper pole at almost 240v input, 
> quite a long burst length, and single shots. I just opened the camera 
> shutter and pushed the fire button several times until it flashed over and 
> latched. These are pretty good sparks for what is around 1.5 bps so it 
> should be great at 150-200bps!
>
> http://www.scopeboy.com/tesla/drsstc/firstlight/ouchcloseup.jpg
>
> I think some sort of EMP is feeding back through the UCC driver stage and 
> latching up the previous stage which is a 4000 series logic chip. I 
> attached LEDs to the UCC inputs and saw that the inputs were sticking in 
> the wrong states and the UCCs were just doing what they were told. Also, 
> adding the LEDs made it more resistant to latchup- a sure sign that the 
> interference was on those nodes.
>
> Here's some more pictures of flashovers.. When running on the lower pole 
> it flashes over the whole time! I can hardly get any spark at the breakout 
> point before it goes.
> http://www.scopeboy.com/tesla/drsstc/firstlight/upperpoleflash1-s.jpg
> http://www.scopeboy.com/tesla/drsstc/firstlight/upperpoleflash2.jpg
> (there was only about 1-2" of output when these happened)
>
> Before it flashes over, the siliconed joint in my primary insulator lights 
> up inside with corona! You can only see part of it in this pic but it 
> glows all the way round.
> http://www.scopeboy.com/tesla/drsstc/firstlight/upperpolecorona.jpg
> That is proper Dow Corning HV rated silicone (donated by work) so it must 
> be a lot of voltage!
>
> Anyway, it works fine if I just stick to the upper pole and turn the 
> voltage down slightly, so that is how it will appear at Derby (God willing)
>
>
> Steve