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Re: [TCML] Looking for MMC Capacitors
Availability of capacitors seems to ebb and flow like the tides. Everyone tells you they're available, and you can't find them anywhere. Then everyone says they're not available, and they're falling from the sky. The world famous CDE 942C20P15K-F models apparently only get made by the Cornell Dublier company when they have big enough demand. That's probably commercial demand, not us tesla hobbyest types. The last run as far as I know (I was informed by a helpful non-automated telephone voice at DigiKey) was just this past month. So they should be coming available from the major outlets.
As of this writing, Dan McCauley has some 942s on his website (easternvoltageresearch.com). And Alan seems to always have some available on eBay, or his website (Teslastuff.com) rain or shine. And while everyone is unique and experiences are always different, I have purchased supplies from both of these guys and have found them to be reliable and honest and I'd recommend going to them before a bigger outlet, because they'll also help you with your questions as well as mailing you a package.
Other sources - Mouser and Digikey just MAY have the capacitors in stock as soon as CDE gets around to shipping last months run.
I have also successfully bought the 942s from a company called RS Electronics, who seems to supply mostly the automotive industry. They don't list the 942s on their website, but if you call them they can usually get them in small quantities (e.g. < 100). For reasons beyond my puny grasp of industry they seem to get the caps in lots of 64.
Other types of caps are recommend and well used by others here. Gary Lau uses a completely different type, which do appear less expensive and work quite well. I have no experience with these, only the 942s.
On Aug 4, 2010, at 10:23 PM, Ray Whiteside wrote:
> I have had a hellacious time finding appropriate caps to buy for my MMC. The
> tank capacitor needs to be close to 10nF and be able to withstand around
> 16kV, so I've been looking for 1-2 kV caps and capacitance values to keep
> the number of strings somewhat reasonable. Polypropylene caps with
> charge/discharge rates over 1000 V/microsecond and all the other above
> requirements have been very difficult for me to track down online, and when
> I finally do the minimum order is something like 150 pieces.
> Essentially I'm sorry for the really noob/seemingly google-able question
> here, but could someone point me to a good source for small coil caps and/or
> another solution? I have already bought one set from a sub-par site, and the
> lack of complete spec sheet on the site led me to end up buying caps with
> the same part number as what I wanted, but another version with 1/5th the
> capacitance value. I am trying to see if I can use some good will from here
> to avoid another such mistake. :)
> Raymond Whiteside
> Tesla mailing list
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