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Re: Spark Gap Sustaining Current (fwd)
---------- Forwarded message ----------
Date: Sat, 06 Oct 2007 12:45:44 -0500
From: Bert Hickman <bert.hickman@xxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Spark Gap Sustaining Current (fwd)
Hi Christopher,
That's actually a very interesting approach! It seems to avoid the
catastrophic "flaming arc" problems of a classic resonant charging
circuit when the charging inductor value is too low, and yet DOES take
advantage of resonant charging of Cp via Lc.
In your circuit (see below), there's no initial current flowing through
the inductor when gap A initially fires, and Cp is assumed to be zero.
As Cp charges through Lc, the voltage across Cp rings up sinusoidally,
approaching about 2*Vsupply. At this point, the charging current drops
to zero, the static gap extinguishes, and the dequeing diode prevents
any significant reverse current flow. As the ARSG rotates to position B,
there's still no current flowing through the static gap and it stays
extinguished as gap B fires, discharging Cp through Lp. As the ARSG
rotates back to position A, the static gap should reignite as long as
the voltage across Cs has not declined too much and there's little
residual charge remaining on Cp.
I know of no simple way to estimate at what voltage the static gap will
eventually fail to retrigger, or how many successive presentations will
work before Cs must be recharged enough to re-fire the static gap. Try
it an see and let us know the results.
BTW, if you simply removed the static gap, I suspect this design would
work even better. The dequeing diode would still block reverse current
flow, thereby "trapping" 2*Vsupply across Cp, and the ARSG still serves
as the main switching element for alternate A-B switching...
Please keep us posted on your results!
Good luck and safe coiling to you,
Bert
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Tesla list wrote:
> ---------- Forwarded message ----------
> Date: Fri, 05 Oct 2007 11:56:33 -0500
> From: Crispy <crispy@xxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Spark Gap Sustaining Current (fwd)
>
> Yep, that's it. Thanks.
<snip>
>>> The function of this special ARSG is to physically interrupt the
>>> charging circuit from the tank circuit when the tank circuit is
>>> resonating. This prevents all of the loss and problems associated with
>>> shorting out the power supply while the tank circuit resonates.
>> I think I have it. Use a non-proportional font to see properly. The ARSG
>> alternates between position A - open - position B - open, etc...
>>
>> Static |\ |
>> + ----o----o o----| >|-----o o---------
>> | Gap |/ | \ |
>> | DQ A \ B O
>> HV + | o O Lp
>> DC In ----- | O
>> ----- Cs | | | | Lc
>> | 0.44uF -----| |----o-----OOOOOOO---
>> | | | ======= |
>> | Cp |
>> | |
>> - ----o-----------------------------------------------------
>>
<snip>
>>
>>> The function of the static gap is different from that of a normal static
>>> gap. The gap in this instance should not be considered as a voltage
>>> controlled switch. The gap's increased propensity to fire a second time
>>> immediately after a first firing must be considered. The gap functions
>>> to pulse power from Cs into the rest of the charging circuit, providing
>>> much higher power during several subsequent iterations of the ARSG than
>>> is drawn RMS from the wall. The special ARSG does NOT fire during the
>>> majority of its iterations (during these iterations Cs is charging).