Re: MMC caps: prices, sources, and types

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "steve" <steve_vance-at-cablelynx-dot-com> 

I'm not sure what dc voltage rating most people go by when building a MMC. I
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 caps
is RELL.
They have the same caps the Geek Group sells for 2.46 each. You have to buy
at least 28 though. Last time I checked the shipping was very reasonable.
http://catalog.rell-dot-com/rellecom/scripts/SkuPage.asp?SKU=162589&PNO=&PNM

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 been
 > having a hard time finding a good source.  Putting that many in series to
 > handle the voltage tends to mean you need more strings, which
 > significantly drives up the price.  I noticed that the Geek Group tended
to
 > 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 is
 > 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 or
15
 > kV transformers, so unfortunately I can't specify.  I guess if 10kV, I'll
be
 > trying to get 150mA, and if 15kV, I'll be trying for 90mA.
 >
 > Thanks for your help!
 > Michael Johnson
 >
 >
 >