From: boris petkovic
Date: Wed, 9 Oct 2002 13:05:29 -0700 (PDT)
Subject: Re: [TSSP] Top Voltage
Paul wrote: > Terry, > > Can you confirm whether or not the sphere/rod was > the breakout > terminal, or were you running into the toroid alone? --- How on earth he could get breakout of the toroid alone of that size (and it is a quite smooth one) with "only" about 200 kV peak? (Not being Terry to answer your question but I think the sphere/rod was on..On other hand ,it is a weird TC world , everything is possible..hmm better Terry answer the question ) --- > > I got the following typical offsets when that > > happened: -2.2, -4.2, -3.8, -0.6, -4.7, -3.8, > -4.2. > > Only when there was visible breakout, hmm, that's > disappointing. > > > I have not thought about the greater meaning here > > It means that 5v times 0.1116uF = 0.6uC of positive > charge > had left the topload and not returned. > > You must have been peaking circa 200kV on the > topload, so > a topload charge peaking at Ctop * Vtop = 25pF * > 200kV = 5uC > by comparison, so maybe 10% of the available > positive > charge is being forced out, never to return. > > Looks to me like unequivocal evidence of that space > charge. --- Yes.That fact is already known,now being confirmed once more.What is unknown are the amounts of charge,their disposition around terminal and contribution to voltage in higher BPS mode runs of disruptively operated coils. --- > > With the toroid alone, no rod or sphere, the > topvolts for 26kV/cm > on the toroid surface is calculated to be 410kV, so > we are seeing > early breakout --- Terry is running OLTC practicaly single shoot ,isn't he?For 200 kV max field would be bellow 13 kv/cm. What gas discharge theory outthere supports serious "strike" ionisation at such field if standard conditions given? I would second to Marco Denicolai's comment about his doubts on 26 kv/cm as something fixed (or even aproximately correct for variety of excitation modes,electrode sizes etc) . I'm especially suspicious for TC waveshapes and that value in single shoot mode.Following Bert's posts and explanations of lowering voltage breakout threshold due to interaction of electrode and generated ion waves due to earlier rf waves,I have one question: These reports were for longer (/CW rf *?) HV runs,or something else? If so,Terry improved OLTC secondary Q (or it was improved by itself) and can do somewhat better by changing k factor to see how rise time effect breakout. I think primary Q still puts quite a limit to all this,but a small improvement is better than no improvment.Also how about not trying quenching at first notch or/and reversing polarity in primary tank? ---- (I hope Terry says the rod/sphere > assy was not > attached! --- Gosh,I don't hope so! (Now ,I expect all the gun fire will be point in my direction becouse of this post;) regards, Boris __________________________________________________ Do you Yahoo!? Faith Hill - Exclusive Performances, Videos & More http://faith.yahoo.com
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