Re: BetterCapacitors

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Chris,

At 11:02 AM 7/28/2002 -0500, you wrote:
>
>A MMC would be the best solution.In terms of size and weight... but I have
>no data to support this conclusion just your guys recomendations....

Everyone gets MMC now days or goes for the cheap salt water caps.  The geek
group has a nice plan for a real good salt water cap and they also sell
nice MMC caps cheap.

www.thegeekgroup-dot-org
http://geekgroup.yi-dot-org:81/

Looks like they are working on their site right now...  Give it a few
days...  Maybe write Chris...

>
>so I need some opinions on a couple things
>
>Is it worth it to route out a source for the thick 30mil PE plastic sheeting
>???
>whats an average cost of a 15-20nf rolled cap?

I can't think of anyone who has made a rolled cap in a year or so now.
When MMCs hit the scene, a number of people dropped their rolled cap
projects right in the middle and made MMCs instead.  I think an MMC is like
1/4 the cost and 1/10th the effort...

>
>Whats the best source for mini caps... The geek group?

Yep.  They have 0.15uF 2000V polypropylene foil caps (Cornell Dubilier
942C20P15K) for about $3.50 each (not sure of price?).

http://hot-streamer-dot-com/TeslaCoils/MMCInfo/GeekCaps/GeekCaps.htm

>whats the recomended ratings for caps not from the geek group?

Polypropylene-foil construction, high-current high-voltage self-healing...
See the list at:

http://hot-streamer-dot-com/TeslaCoils/MMCInfo/good-bad.txt

>when is the next geek group order going through?

Ask Chris :-)

"Christopher Boden" <chrisboden-at-hotmail-dot-com>

>
>anyone have a guess at much would it cost me in resistors and capacitors
>from the geeks to build a 15nf to 20nf MMC?

See this chart:

http://hot-streamer-dot-com/temp/MMCcapSales.gif

>Where is a good page to get the math for doing up a MMC?

http://hot-streamer-dot-com/TeslaCoils/MMCInfo/mmcinfo.htm
http://hot-streamer-dot-com/TeslaCoils/MMCInfo/MMCPower4.html
http://hot-streamer-dot-com/TeslaCoils/programs/Mmccalc2.zip

>What type of resistors do I need to use?

"I" just get 10Meg ohm 1/2 carbon film types.  Yageo 10MH

http://www.digikey-dot-com/scripts/us/dksus.dll?Criteria?Ref=88368&Cat=30802464

They are used over they're voltage rating but they work fine.  I have a few
thousand extra so write me and I'll send you a bunch for free.
terrellf-at-qwest-dot-net

>Say I built a MMC to go with a NST 12kv60ma, if I buy another NST can I just
>build another MMC and paralel it in with the other one? Or do I need to
>reconstruct the entire unit?

You just simply parallel it up.

>
>I can probably figure out a lot of this if someone points me to the right
>information, but I would really like the current opinions on capacitors. a
>little help with the math wouldnt hurt either.....

http://hot-streamer-dot-com/TeslaCoils/MMCInfo/mmcinfo.htm

See the little DOS program at:

http://hot-streamer-dot-com/TeslaCoils/programs/Mmccalc2.zip

Also a Excel spreadsheet form too.

http://hot-streamer-dot-com/temp/MMCcalc2xls.zip

The thermal dissipation value for these caps that MMCalc2 asks for should
be "22".

However, Mark Broker's chart at:

http://hot-streamer-dot-com/temp/MMCcapSales.gif

already has everything figured out for normal coil configurations.

>My salties are tough and work but I hate moving the big heavy darm things...
>
>I have been wondering has anyone ever built a primary on one of those round
>plastic sleds?

Sounds like a great idea!

Cheers,

	Terry

>
>Thanks
>Chris Dowdy
>