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Re: NST Resonant Charging?
Tesla List wrote:
>
> Original Poster: Greg Leyh <lod-at-pacbell-dot-net>
>
> > Original Poster: Sulaiman Abdullah <sulaiman-at-lityan-dot-com.my>
> >
> > > Using simulation software you can prove to yourself that even though
> > > the capacitor is discharged every 1/2 cycle of the mains the highest
> > > voltage IS produced for the 'resonant charging' scheme, and very
> > > nearly at the zero-crossing of the mains input. By SIMULATION only at
> > > the moment a higher power/energy (fixed pps) is achieved with about
> > > 20% higher capacitance.
>
> I ran the ckt on MSim7.1, which confirms that a 60Hz
> resonant charger requires most of the 60Hz cycle to
> supercede the open ckt voltage to any useful degree.
>
> Here's the results from the simulation: (Qchg ~10)
>
> Break Rate Overcharge
>
> 240BPS - 18%
> 120BPS - 25%
> 60BPS - 103%
> 30BPS - 181%
> 15BPS - 230%
>
> As I understand it, NST's are not designed to withstand
> even their own open ckt voltage indefinitely, let alone
> a voltage rise due to resonant charging.
>
> This suggests that perhaps a static gap which is firing
> erratically (thus producing a low BPS and a high overshoot)
> may be the silent killer of marginalized NST's.
>
> IMO, resonant charging seems more a bug then a feature,
> especially if it cannot be used in the 200-plus BPS range.
> --
>
> -GL
> www.lod-dot-org
Greg,
Can you simulate a voltage-controlled switch for the main gap instead of
forcing the breaks to more closely approximate a static gap? My freebie
version didn't give me this capability. :^)
Also, does the PSpice model show any increase in capacitor recharge
current between breaks as we get closer to mains resonance? I'm seeing
breakrates between 360 and 480 BPS from a pair of 15-50's with a total
gap of over 0.5" (I know, I'm really overstressing the NST's...).
-- Bert --