Re: NST's shorting out.

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Martin,

Just to add to Terry's post.

MMC's have a magic quality to them. The situation you found yourself 
in is a perfect example. Prior to MMC's, caps were the #1 hardest 
component to come by (seriously). Transformers have since taken their 
place, but only because MMC's are now common place. MMC's can be 
hashed out into any cap value you require. That is the major 
advantage that is often not realized. It's the same thing you were 
thinking previously (using the caps you had around to arrive at a 
possible workable value). MMC's are no different. With the MMC 942 
style caps, you can build any cap value you chose. Just keep in mind 
that cost goes up with the quantity of caps. So try to squeeze out 
your options using one of the MMC charts Terry selected.

I also have the JavaMMC calculator at my website which may assist
http://www.classictesla.com/java/javammc/javammc.html.

It's a basic calculator, but it may help hone in on what you want if 
you choose to seek out an MMC solution (which is the best advice I've 
heard for your situation).

Dr. Resonance is my recommendation as the person to buy these caps 
from. He's helped a great deal of people on the TCML over my past 10 
years with various components which would otherwise be difficult to 
come by. His generosity of making available to this community these 
types of components is nothing less than a blessing to the TCML.

Take care,
Bart


Tesla list wrote:

> Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi Martin,
>
> At 06:56 PM 3/20/2006, you wrote:
>
> > ......
> >
> > "Get MMCs like everyone else ;-))  You might be
> > able to just get a smaller value to add to your
> > 30nF cap and save some money.  It all sort of
> > depends on how you can mix and match it all together."
> >
> >
> > Last question (hopefully!).  Exactly what are MMC's and where can I 
> > get them?.  I have heard the term but am not familiar with 
> > them.  Are they what are known as "self-healing capacitors?"
>
>
> MMC stands for Multi Mini Capacitor.  A pretty new type of Tesla 
> coil capacitor thought up around 2000.  We take a bunch of small 2000V,
> 0.150uF, polypropylene, self healing, 432 peak amps, 13.5 RMS amps 
> (70C 100kHz) and put them in series and parallel to make our caps:
> Series to get to the peak voltage we need an parallel to get more 
> current.  MMC love to be run over voltage, but never over current.
>
> http://users2.ev1.net/~nmyreality/tesla/capacitor/mmc.htm
>
> http://www.google.com/search?hl=en&q=%22MMC+capacitor%22&btnG=Google+Search
>
> We all really like the CD 942 types especially the 942C20P15K (we 
> worry a little about other types we are not sure of in this super 
> hard core application 
> http://hot-streamer.com/TeslaCoils/MMCInfo/good-bad.txt ) :
>
> http://cde.com/misc/h942.htm
>
> http://cde.com/film/9422000.htm
>
> http://www.hot-streamer.com/TeslaCoils/MMCInfo/mmcinfo.htm
>
> http://www.hot-streamer.com/TeslaCoils/MMCInfo/GeekCaps/GeekCaps.htm
>
> Dr. Resonance here on the list sells them and they can be bought 
> commercially from a number of places too:
>
> http://catalog.rell.com/rellecom/scripts/SkuPage.asp?SKU=162589&PNO=&PNM=
>
> http://catalog.rell.com/rellecom/scripts/SkuPage.asp?SKU=798629&PNO=&PNM=
>
> They cost $2.58 here, but they are going to lead free now and the 
> price for those is $3.22 :-((  I am not sure they make the lead 
> version anymore...
>
> Here is a chart that says how many to put in series or parallel for 
> various NST and gap configurations:
>
> http://hot-streamer.com/temp/MMCcapSales.gif
>
> This chart also uses the 0.100uF caps of the same type.  You can 
> also ask around since many of us have extras...
>
> The MMC basically made the old oil rolled caps "extinct" in about 6 
> months.  They are very hardy caps and difficult to break.  I think 
> like 90% of the new coils use them now.
>
> They can recover from an overvoltage like 100000 times.  We use them 
> deliberately at 2000V even though that is sort of rough on 
> them.  They make only last 75 hours like that:
>
> http://hot-streamer.com/temp/CD942C20P15K-MMC-Capacitor-Lifetest.pdf
>
> but that is long enough for most of us ;-))
>
> > Again, thanks Terry for your help and patience with all my questions.
>
>
> That is why we are all here ;-))
>
> Cheers,
>
>         Terry
>
>
> > Martin