Re: No Terry filter

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Gerald  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi John,

I guess I can believe this.  With a static gap the waveforms are very 
irradic (lot of transients with pseudo chaotic timing.).  I also dont think 
the main gap fires all that reliably at the same maximum voltage (I dont 
think I fully understand this).  I ususally adjust the main gap until the 
safety fires ocasionally.  But with a SRGS all the transients are 
sychronous with the charging waveform so the waveform is repeatable.  I 
agree that the safety gap is probably not necessary given the caveat that 
the timing is not too late after peak and nothing else fails.

If the SRSG stops firing (for example), energy will no longer be taken out 
of the system and I would bet the NST would saturate and put the system 
into resonant charging with uncontrolled rise (become ferroresonant).  I 
had the safeties opened up and the SRSG removed so I could study the 
phenominum. The NST output increased controllably as I slowly ramped up the 
variac and then suddenly snapped to about 29 KV in about 1/2 a second with 
no further increase in the variac.   The power factor also snapped to 1.0 
(with no PFC's) indicating resonant charging even though I had a Cp = 
2.6*Cres.  I believe it was the MOVs that limited the rise since their 
voltages added up to 28.8KV.  Both NST's survived.

If the rotor timing gets too late, the firing stops.  I believe this is 
because the NST starts to saturate and the phase of the charging waveform 
is pulled up in time making the firing voltage to low to fire.  Again, no 
firing results in ferrorance and uncontolled rise without protection.

Gerry R


> Original poster: FutureT@xxxxxxx
> I've had good results over the years too without any safety filters.
> My old research coil with the 12/30 NST, then later the TT-42
> coil never ruined any transformers provided I used a SRSG.
> Even the use of resonant sized cap values did not destroy
> the NST's provided that an SRSG was used.
> The static gaps were prone to destroying the NST's despite
> shorter output spark lengths.  I do use safety gaps however.
> In SRSG use, they never fire however.  They're there in case
> something else fails.
>
> John