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Re: Final Capacitor Test Results



Hi everyone,
             I'm rather concerned about capacitors right now just 
after reading Richard Wayne Wall's story about his cap failure on the 
usa-tesla list. I've just been back over a number of old posts, in 
particular Ed Sonderman's to re-read about his CP cap failure. 
Something I read that didn't intuitively make sense about his 
operating conditions has made me wonder (apologies for the reformat 
Ed)...

> Then I reconnected the whole system one component at a time - and
> everything worked normally.  Now I was puzzled, why did it work
> now, but not the last several times I tried this?  I ran the system
> for several minutes off and on, trying to dial in the best tune on
> the primary.  I had the primary current set at about 25 amps.  Then
> I noticed that I had forgot to plug in the resistor bank for the
> parallel load to the welder.  I plugged it in and tried the system
> again and it would just barely fire.  Primary current dropped to
> about 10 amps and the gaps would only just barely sputter.  This
> has apparently been my problem all along.  I don't understand it at
> all.  Adding resistance in parallel with the welder should increase
> the primary current.

I wonder whether there isn't some kind of resonant charging going on
and adding the resistance completely killed the Q of the input choke
(welder)? What do others think? How could adding that resistance kill 
the system so completely? Please, if anyone has ideas let us know. I 
for one hate unexplained mysteries. It was interesting what Richard 
Quick said about synergism in the system. At 60Hz, the cap reactance
is about 106kOhms, and the reactance of the primary coil (assume 
around 100uH) is a fraction of an Ohm. So the capacitave reactance
transformed back through the pole pig to its primary is the dominating
reactance seen by the mains. I wonder if this was in resonance with
the welder? Any ideas on this one are most welcome. I'm only sorry I
can't be there to measure it.

Malcolm