Re: How could a pulse cap operate in TC?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mark Broker" <mbroker@xxxxxxxxxxxxxxxx>


> > i can imagine 100  942C20P1K caps for 2 kw 100 bps tc, but if 2000 volts
> > is maximum peak-to-peak rf voltage, then i need 400 caps - it`s stupid -
> > so for the price, so
> > for the size of MMc :-)
>
> I have run them at 3000+ volts to just to use fewer caps and save money
> (EMMC).  Only when they are obviously run it a constant breakdown do they
> fail.  2000V is very safe but "I" have no problem running them a lot 
> higher ;-)

They typically breakdown internally at about 5000V each.  As far as I know, 
"most" people's MMCs are designed with ~2000V per cap at expected firing 
voltage (roughly 1.4* Vhv).  Pros like Dr. Resonance use a lower voltage 
rating (I forget the formula, but it works out to about 1200V) for a cap 
that should last a lifetime in a museum setting.


> http://hot-streamer.com/TeslaCoils/MMCInfo/GeekCaps/GeekCaps.htm
> http://hot-streamer.com/TeslaCoils/MMCInfo/GeekCaps/TestSetUp.jpg
> http://hot-streamer.com/TeslaCoils/MMCInfo/GeekCaps/PowerScope.jpg
> http://hot-streamer.com/TeslaCoils/MMCInfo/GeekCaps/ScopeCurrent.gif
> http://hot-streamer.com/TeslaCoils/MMCInfo/GeekCaps/HVTest.jpg
> http://hot-streamer.com/TeslaCoils/Programs/MMCCALC2.ZIP

> http://hot-streamer.com/TeslaCoils/Programs/MMCCALC2.ZIP
> http://www.classictesla.com/java/javammc/javammc.html
> http://hot-streamer.com/TeslaCoils/Programs/MMCcalc2xls.zip

The most recent testing is explained here:
http://www.pupman.com/listarchives/2003/May/msg00682.html

The test subjects are presumed to be representative of bulk product, and 
the CDE caps may or may not have been "improved" some more since then.


> > p.s.
> > 942C20P10K -  nowadays do we have something better by the price/quality 
> > value?
>
> I don't think so...

For $ / (C*V), yes: the 1600VDC caps have much higer capacitance 
ratings.  While we were still selling caps, we were looking for enough 
interest in some of the ~.68uF, 1600VDC caps, but there was not enough to 
make an order.  Those would make a smashing MMC for a "big" TC. . . .

IIR, our Gemini Twins run about 12kVA at 360BPS.  I believe the MMC uses 
about a hundred 2kV, .15uF caps.

Mark Broker
The Geek Group