[Prev][Next][Index][Thread]

Re: NST Resonant Charging?

Hi Greg,
	The basic trick is that the primary capacitor's reactance cancels the
neon's secondary inductance at 60 Hz and allows greater than normal voltage
and current to be delivered.  I have computer models and can get real
waveforms of this if you wish.  Unfortunately, it can get real complicated.
 I work with waveforms and models all the time so I have an intuitive feel
for the whole thing, but I can't think of and easy way to explain it....
	If you have a windows computer with about 30 meg of drive space, win 95 or
better and 16 meg of memory, you should get the MicroSim demo and my model
and you could see all the stuff yourself.  Let me know if you are
interested.    The MicroSim program is vastly powerful and not too hard to
get used to....

	Terry


At 08:16 PM 10/13/98 -0700, you wrote:
>Hi All,
>
>I still don't understand how resonant charging could possibly
>work in a practical NST-powered TC. 
>
>Assume the cap is set to Xl of the NST's leakage inductance,
>which gives 0.011uF for a 15kV 60mA NST (this seems to be the 
>most popular method of choosing Cpri).  
>Then the cap resonates with the NST at 60Hz, and the voltage 
>will build with each cycle -- and if the gap is set to not fire, 
>the voltage buildup will ultimately be limited by the Q (and the
>breakdown strength) of the charging circuit.
>
>But what if the gap fires at each peak, at 120BPS?
>Then the energy is stolen from the cap every 8.3 mS, preventing
>any significant resonant rise!  Remember, this charging circuit
>resonates at 60Hz, and therefore requires a significant portion
>of the 60Hz cycle to build past even the normal open ckt voltage!
>
>The charging slope could of course be speeded up by using a smaller 
>capacitor, but at the expense of ultimately limiting the available 
>primary energy.  The other important point here is that the firing
>rate *must* be 60BPS or a multiple thereof, in order to get any
>decent performance out of a 60Hz-fed resonant charger.
>
>What is really going on?  Does anyone have voltage waveforms 
>of a NST resonant charge cycle in action?
>-- 
>
>
>-GL
>www.lod-dot-org
>
>