More DRSSTC fun!

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Steve Conner <steve@xxxxxxxxxxxx>

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