MMC Capacitor voltage - How long will they last???

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi All,

Somebody IS finally doing something :O)

http://hot-streamer.com/temp/GreatCapTest-003.jpg

http://hot-streamer.com/temp/GreatCapTest-002.jpg

http://hot-streamer.com/temp/GreatCapTest-001.gif

Cheers,

        Terry




> Hi,
>
> Somehow, someday, somebody, has to do something... :-))
>
> Probably the "last unknown" of MMCs is how long the (CD 942C20P15K) 
> will tolerate say 60Hz at 2000Vp-p....
>
> Maybe do a bunch of different voltages to make a nice graph of 
> 'lifetime vs. over voltage'...
>
> That would tell us all we still want to know...
>
> Cheers,
>
>         Terry
>
>
>
> > One usually overrates the cap for AC use.  I suggest Erms x 2 as a 
> > correct DC rating, so with your 15 kV AC xmfr, for a near bullet 
> > proof cap bank, you want a cap bank rated at 30 kV DC.
> >
> > If you are using 0.15 uF 2 kV caps in your strings then each 15 cap 
> > string would be rated .01 uF at 30 kV DC.
> >
> > With a 30 mA xmfr you need approx .014 uF capacitance so you cheat 
> > a bit and use 11 caps in each string.  This gives you a single 
> > string rated .0136 uF at 22 kV DC which will work fine with your 30 
> > mA xmfr.  You try to avoid a .01 uF match with the xmfr as the cap 
> > bank might resonate with the xmfr and damage the xmfr.  Going a bit 
> > higher usually works very well.   1.2-1.3 x Cres.
> >
> > Dr. Resonance