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Re: [TCML] Effect of doubling the input current



Phil,

What probably happened is that your NSTs are
resonant charging now, giving very fast charging to
the caps.  This is greatly increasing the break rate.
This is causing spark length growth via higher
break rate.  In some cases, the sort of thing
you describe can occur.

It's likely that your system is drawing a lot more
than double the current.  NSTs can draw a lot
more current than they are rated for if they
get into the resonant charging area.

Although NST's are current limited, this  applies
to use with a resistive load.  With reactive loads,
they can draw extra current.

John
--


-----Original Message-----
From: Phil Tuck <follies@xxxxxxxxxxxx>
To: tesla@xxxxxxxxxx
Sent: Mon, 8 Dec 2008 6:08 am
Subject: [TCML] Effect of doubling the input current



Hello Group.



I have a query over charging currents following an exercise on my coil of
doubling the input current.

I was originally running my old 10k/48 into a 0.02143 uF cap.



However I recently acquired two identical [new] 10K/50 's and tried these in
parallel for 100 ma.

My coil was already 'ball park' tuned for the 48m/a NST, when I substituted
the two new 50 ma NST's.



I left all other settings on the coil alone (apart from making sure the
safety gap was still appropriately gapped - voltage outputs can vary despite
what the labels say)



I did not expect any really significant difference as it was only the
current that had increased not the voltage, nor my cap size.

The 'Freau' formula of Spark length is 1.7 x SQRT(Bang Energy x BPS). Now
the bang energy [or so I thought] depended on the value of the cap x the
voltage at the gap squared.



As I was still using my original sized CD' MMC caps of 0.02143 uF and not the recommended size for 10/100 of 0.0477uF, why did I get such a massive increase in performance. I would estimate the spark lengths are double to
the 48 ma original NST.



If I had doubled the current and also doubled the cap size [necessary to
have charged to them the same level] I could understand why.



Is it that my tuning was less than perfect originally and with the 100ma
NST's it is nearer the mark ?



Phil



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