OL-DRSSTC - 13

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi All,

Today I did some single shot testing at ~170v buss:

http://hot-streamer.com/temp/OL-DRSSTC-2005-10-15-001.gif

Primary current yellow, buss voltage is blue.

As expected, the burst shortens up so most of the real power is in 
the first 400uS.  This is an interesting tuning spot since you can 
see the modes switching between poles as the streamer forms.

The droop is not bad at all anymore but the turn-on timing is still 
about 950nS out:

http://hot-streamer.com/temp/OL-DRSSTC-2005-10-15-002.gif

It tries to turn on at ~600nS but it seems to have to build up steam 
to drive the current out.  It stutters for about 200nS while the gate 
voltage builds up.  The turn on transition is about 350nS against 
about 220amps.  Not sure how bad that is.  I will find out when 
running it full blast ;-)  The total power is not bad, but the peak 
power is high there...  I may get away with it...

I moved to the big variac now.  The little OL-DRSSTC get lost between 
the variac and scope ;-)

http://hot-streamer.com/temp/OL-DRSSTC-2005-10-15-003.jpg

Note the "blast shield" between the OL-DRSSTC and the scope now :o)))

Here are some little sparks at only 35V buss for DC Cox :o))

http://hot-streamer.com/temp/OL-DRSSTC-2005-10-15-004.jpg

I am a little worried about loop current.  With a primary inductor, 
the buss voltage can hit 240VDC where the computer says:

http://hot-streamer.com/temp/OL-DRSSTC-2005-10-15-005.gif

It can hit 600 amps!!  That is sort of "high"...

I can reduce system power buy lowering the buss capacitance, reducing 
buss voltage, and decreasing the primary capacitance.  But I think I 
will leave as is since I really don't want to use the buss inductor 
at all.  That would put the nominal firing voltage at 170VDC which 
might be just right....

Computer says...
435 amps peak
36 Arms primary current
18A peak AC line current
7.9 Arms AC line current
390 W buss power
225 W streamer power
150kV peak output voltage

Seems just fine ;-))  I should note that streamer models are weak and 
the above numbers do depend a lot on that (especially streamer 
power).  But history says that those are good numbers in any 
case.  Steamer power could probably be better estimated as "BussPower 
- SystemLoss" in the DRSSTC case...

Cheers,

	Terry