Re: [TCML] MMC Primary Caps for Sale or to recommend

[bartb <bartb@xxxxxxxxxxxxxxxx>]

Hi Stephen,

Yes, Terry's post is absolutely valid. Terry also posted a list of known 
"good and bad" caps.
http://www.classictesla.com/hot-streamer/TeslaCoils/MMCInfo/good-bad.txt

The 942C series is the one I would recommend as they are probably the 
most widely used by coilers and have an excellent track record.

Here is an MMC chart which might be of use.
http://www.classictesla.com/download/mmc_cap_chart.pdf

Because your stacking NST's, the options of course change and the 
current doesn't go past 120mA. But, you can also use a program or 
someones Excel spreadsheet to work out what you need.
http://www.classictesla.com/java/javammc/javammc.html

Regards,
Bart

Stephen Hiscock wrote:
> I am looking for recommendations for Primary Caps to use for an MMC 
> style capacitor bank.
> Does anybody recommend specific brands or does anyone have anything 
> they would like to sell me.
>
> I was recommended recently by Bart that I should use 1.3 to 1.5 times 
> the NST resonant value.
> so I will need 6.366nF x 1.3 = 8.3nF to 9.5nF for each 15kv/30mA 
> transformer I have.
> and I have 5 (or 6 or 7 if I use the 3 phase circuit at home).
>
> Basically I need capacitance in multiples of 9nF @ 15kV RMS up to a 
> total of 54nF so I can disconnect transformers for different power 
> levels.
> All my transformers are rated the same 15kV @ 30mA
>
> Terry fritz posted this on:
> http://www.pupman.com/listarchives/2000/May/msg00528.html
> 14 May 2000
>
> He tested these caps:
> "0.047uF  1500V Arcotronics capacitors "RS" from Richie Burnett
> 2.5 amps RMS  350kHz  2.2 degrees C
>
> 0.022uF  1200V Panasonic Q-E??  from Bill Noble
> 2.0 amps RMS 350kHz  4.8 degrees C
>
> 0.056uF  1600V Phillips 376 KP/MMKP HQ from Finn Hammer
> 3.5 amps RMS  350kHz  1.5 degrees C
>
> I also retested my Panasonic with my more refined setup of today
> 0.056uF  1600V Panasonic ECW-H16563JV
> 3.5amps RMS  350kHz  3.1 degrees C"
>
> and found the following points:
>
> "I would say the important MMC cap
> parameters are as follows:
>
> 1.  Polypropylene is the ONLY acceptable dielectric
> 2.  "Self healing"
> 3.  1500-2000 VDC rating  The ~630VAC rating is immaterial
> 4.  High-energy, pulse-discharge, high-dI/dT, high-dV/dT, or good
> continuous end/lead attach is a must.
> 5.  0.05 to 0.10uF seems to be the best range of values-all things 
> considered.
> 6.  WIMA, Phillips 376, and other relatively large potted styles seem to
> run a bit cooler."
>
> The post above was quite old, but are these recommendations still 
> valid for capacitors to use as MMC primary Caps?
>
> Thanks
>
> Stephen
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