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MMCs & Currents



Original poster: "Steven Ward by way of Terry Fritz <twftesla-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>

Hello list,

Im looking for some opinions and answers here.  Im finishing up my large 
coil, and have already obtained the capacitors.  They are GE .68uf 1200v 42L 
series.  Looking at the Cornell Dubilier ratings for their same cap, they 
list a I peak of 854A.  Im powering my coil with a 15000v 120ma supply.  I 
am not using a rotary gap, but a oversized static gap with lots of 
cooling(im still shakey about this).  So assuming my GE caps can handle the 
854A peak, does it sound like im ok with these?? Im using a single string of 
24 caps in series (.0283uf -at- 28800vdc).  I have a few other questions about 
caps while im at it:

1. Do SRSGs cause more or less stress on the caps than with a static gap? 
I'd assume less with less discharges per time period

2. What is more stressful, 120bps or 240bps?(i think 240)

3. Has anyone used static gaps with this much power?  Did it work good?

Im lead to believe that i may be ok because of this scenario:  A friends 
coil uses 12kv 120ma supply with 2 strings of .1uf 2000v CD caps(9 caps per 
string).  These only have a I peak of 285A.  We ran his coil for about 2-3 
minutes with out any detectable warming of the caps.  He is also running a 
static gap.  We achieved 51" sparks :)  not bad!  Im guessing that since i 
have about 3X the I peak rating, that my single string could run better than 
his 2 strings.  Is there anything that im not understanding here??  And just 
in case anyone is wondering, the caps are 44mm wide and 27mm in diameter.  
Im still awaiting my primary supports(in the mail), then i will basically be 
done!  Ill give all the details when im finished.

Steve Ward



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