Re: MMC caps: prices, sources, and types

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

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
hurry.

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.

Dr. Resonance


 >
 > 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
 >  >
 >  >
 >  >
 >
 >
 >