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Re: MMC caps: prices, sources, and types
Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
We have approx 300 pcs of MMC caps in stock if you needed a smaller
quantity. They don't weigh much and could be shipped FedEx if you're in a
We always use 3 x Erms for our commercial TC's but you could probably cheat
and go 2.5 or 2.2 x Erms on a coil used only part time.
> I'm not sure what dc voltage rating most people go by when building a MMC.
> have used one built with a dc rating twice the transformer RMS output
> voltage for about 5 months without any problems. A good source for the
> is RELL.
> They have the same caps the Geek Group sells for 2.46 each. You have to
> at least 28 though. Last time I checked the shipping was very reasonable.
> Steve Vance
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Saturday, May 08, 2004 11:54 AM
> Subject: MMC caps: prices, sources, and types
> > Original poster: pepperman-at-softhome-dot-net
> > I've been trying to price an MMC, but using the recommendations I've
> > generally seen (e.g. 3-4x the rated voltage of your transformer) I've
> > having a hard time finding a good source. Putting that many in series
> > handle the voltage tends to mean you need more strings, which
> > significantly drives up the price. I noticed that the Geek Group
> > not use as many in their MMC, and it seems to perform acceptably.
> > So what would you say the minimum combined DC voltage rating (as a
> > percent of the transformer voltage) is to have an MMC that will perform
> > acceptably and still have good reliability? I'm not overvolting the
> > transformers on a variac, so that shouldn't be an issue.
> > I'm also looking for a good source for the caps. I know the Geek Group
> > generally a very good source, but my time frame doesn't allow for the
> > delay it would take to get caps from them (they won't get another
> > shipment in until 5/31). What other sources would you recommend for
> > good (and cheap!) caps? And would any type other than the metallized
> > polypropylene caps still be acceptable?
> > Finally, what would you say to expect to spend to put together an MMC
> > for a 1.5 kVA Tesla coil? I'm not sure yet whether I'll be using 10 kV
> > kV transformers, so unfortunately I can't specify. I guess if 10kV,
> > trying to get 150mA, and if 15kV, I'll be trying for 90mA.
> > Thanks for your help!
> > Michael Johnson