Re: Over-voltage at Synchronous Gap ? ? ?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi Dan,

At 06:41 PM 9/14/2003 -0400, you wrote:
>I am having some interesting phenomenon occur at the safety gap I have at my
>SRSG gap.
>
>If I adjust my SRSG to the point of which (should yield 75% to 100% maximum
>voltage at primary capacitor), i get firing of my safety gap with
>loud bangs (which are likely because the MMC is discharging into the safety
>gap)

??  The safety gap should be in parallel with the main gap.  It should not 
directly short the primary cap.  If the main cap is being directly shorted, 
the high current may hurt the MMC.  The safety gap's current should still 
be limited by the primary coils inductance.  Maybe double check the wiring 
there.

>The safety gap is adjusted slightly larger than the no-load voltage
>on the NST.  I am confused to why this gap is firing as I am using a LTR
>type capacitor and didn't think i could get over-voltages using a SRSG.

As Kurt showed, maybe you need slightly more MMC capacitance.  If you are 
not using a Terry filter and don't have some of the same losses involved, 
results may vary a little.  I would just add a little capacitance to the 
primary cap till things quiet down.  If you are using a 0 - 140VAC variac, 
that may over voltage things a bit too.  Tuning may be an issue as 
well.  If the secondary system does not use up the power properly, it may 
tend to raise the primary voltage up.

So tune the coil well and maybe add a little more primary 
capacitance.  SRSG timing can also be fairly touchy and can cause 
misfiring.  It should just all be a matter few minor adjustments.

Cheers,

         Terry




>Any thoughts??
>
>Specs on my small coil are:
>
>15kV, 60MA NST
>0.0257uF, 24kV (MMC - LTR sized)
>Standard secondary and primary coil
>
>The Captain