[TCML] Solid state efficiency, was: mini Tesla coil specs

[Ken or Doris Herrick]

This is getting curiouser & curiouser.  I've now simulated a spark load: 
50 us duration & into 10K to gnd.  Using secondary feedback to establish 
oscillation as I have been doing, and the non-resonant primary,I find I 
get a whopping primary-current surge during the spark event.

Surprise, surprise!...that's from the (to be expected, dummy!) big 
glitch in secondary current.

/However/...  As I recall from my first experience some years back, I 
noticed no such surge; checking the secondary's return-current on the 
scope; there was essentially no change.  Perhaps 10K is too low an 
impedance for the spark?  So...I increase it to 100K with a mouse-click 
or 2 and find a negligible glitch during the "spark".  So what's the 
better simulation of spark impedance, I wonder?--10K or 100?

KCH

-------- Original Message --------
Subject: 	Re: [TCML] Solid state efficiency, was: mini Tesla coil specs]
Date: 	Sun, 15 Nov 2009 13:43:44 -0800
From: 	Ken or Doris Herrick <kchdlh at sonic.net>
To: 	Tesla Coil Mailing List <tesla at pupman.com>



So almost immediately...a follow-up:  Belatedly I thought to resonate 
the primary & try it again.  This time, a) the current's a sine-wave all 
the way; but b) switching /starts out /near current/ /z.c/./ and after 
about 4 cycles it's shifted to current-peaks, where it stays.  The 
current is, of course, a lot greater due to the series-resonance, 
causing the secondary's output to rise faster.

But a) where's the advantage, if switching drifts toward current-peak.  
And b) how to handle the greater current?  (Bigger hardware, that's how!)

And finally:  Whichever way one goes, it seems as if one will have to 
put up with switching near current-peaks--unless one can produce the 
spark within the 1st 4 cycles or so in a DR design.  I haven't simulated 
that yet.

Comments?

KCH

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