Re: 15kva 14.4 kV Transformer.. (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Moderated and approved by: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Fri, 22 Dec 2006 22:18:51 -0700
From: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: 15kva 14.4 kV Transformer.. (fwd)

Hi,

Of course,

"Steve knows" "full well" about MMCs ;-)))))))))))))

But just for "statistics", what was the failure mechanism????????????

Peak current, RMS current heating, pure over voltage, Corona damage with 
old age...????????????

The thermal time constant in the IGBT's thermal expansion coefficients is 
far bellow the "ripping and tearing" point at say 60Hz and above...  So 
heating and cooling is a "don't care" unless you turn it "on and off" a LOT 
(like 50,000 times ;-)))...

If you really "don't know" better get hold of "ScanTesla" :o)))))))  But 
prolly RMS current and over heating then...  Polypro melts at less than the 
boiling point of water...  Cut them fried caps "open" and you will "see" 
inside...

Cheers,

         Terry


>Excellent DC!
>
>I find that my MMC eventually fails (before the IGBTs provided no
>"special events" occur).  I have one DRSSTC that has gone through 2
>MMC banks now, but still has the same IGBT set.  It consistently pumps
>out 6 foot sparks at 1300W input.  If given the chance, id also try
>running one of my coils for extended periods of time to find out where
>the bottleneck in the design is.
>
>Steve Ward