RE: Hi Power Discharge "Disruptive"

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com> 

 >That sounds good.  Is it anything like the load model suggested in
http://www.pupman-dot-com/listarchives/2004/October/msg00088.html

Yes. I have decided to just use the "Loaded Q" metric as it means I don't
have to get my hands dirty measuring streamer capacitance accurately ;)


 >How are you measuring topvolts?  Through an E-field probe calibrated
 >against the predicted topvolts at small signals?   If so then you're
 >measuring a signal proportional to Q in Q = CV where both C and V
 >are variables.

Yes, that's how I'm doing it. The E-field probe is just a 100:1 HV scope
probe with a 8" metal disc attached to the end. I am using a breakout on the
opposite side of the coil to direct the streamers as far away from the probe
as possible.


 >If you turn to the model
 >and impose a load sufficient to give a very low Q like 6, then does
 >the model show a similar 50-75% voltage reduction, or more?

It would be more of a reduction if the load were present from t=0, but of
course it's not. My PSpice model switches on the streamer load at a time
roughly equal to when the real coil breaks out. I can get any voltage
reduction I want by manipulating the simulated breakout time (so it's an
extra degree of freedom to worry about)


 >The challenge I think will be to show that the E-field probe
 >calibration factor C is controlled and its variation compensated for.

Do you (or anyone else) have any suggestions as to how this could be done?
Maybe I could run with the same drive voltage but directing streamers
towards the probe, and see if the E-field measurement changes compared with
what I get when the streamers are on the other side?


 > http://scopeboy-dot-com/tesla/experiment/
 >The noise spikes
 >in the image 100bps_36in_closeup.jpg are interesting.
 >There's an initial strong burst of
 >HF just as the system fires, so you must be picking up something
 >more than just topload discharge.

I think the initial burst of HF is the switching noise of the IGBTs. It's
still present when breakout is suppressed, even though all the other spikes
vanish.


 >I hope we can hear more about the stuff going on there,
 >are you working by yourself?

The University of Strathclyde High Voltage Technologies group are providing
the lab space. (A message from our sponsor! Send your kids to
http://www.eee.strath.ac.uk !!!!) But I am working on my own. Not completely
though, as I can ask you folks questions ;)

I've been too busy to get any more experiments done but I hope to be going
back in 2 weeks time and I will keep you all posted on developments.


Steve C.