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RE: Capacitor! (Ok, ok...)

I used the Panasonic ECW-H16333JV (ECWH series) for my "Mini-Twin". The
total capacitance of the EMMC is .0066uf It's made up of two strings of 10
(.033uf) capacitors.  It's cheap, reliable, and easy to construct. You can
sorta see the configuration at
http://fp2.hughes-dot-net/brianb/images/Tesla/Mini-Twin/mt7.jpg This
configuration was hammered for a number of hours at 600khz and is still
running strong.

For information on the larger EMMC I assembled check out
http://fp2.hughes-dot-net/brianb/emmccaps.htm
 
Have fun, Don't fry...

Brian Basura



-----Original Message-----
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, November 11, 1999 11:26 AM
To: tesla-at-pupman-dot-com
Subject: Re: Capacitor! (Ok, ok...)


Original Poster: Travis Tabbal <bigboss-at-xmission-dot-com> 

Sure you don't want to build them? ;) The big mess is kinda fun. ;) 

Serriously, I would just go buy some MMC caps from digikey or someone
else if you can find a better price and put together an MMC. For
...006-.007 uF that's going to be a cheap cap. 

Terry posted about a week ago about the Panasonic 0.056uF 1600V
polypropylene caps. He had some he was willing to sell at $1.40/per.
Digikey has more, Part #P10516-ND. You can talk to him at:
twftesla-at-uswest-dot-net.

If you really only want .007uF you should look for a smaller uF value so
you can get more strings to help distribute the current. This is the
route I'm taking, although I'm in on a group purchase allready so I am
not getting those particular caps. 

I decided to do a little searching for you. I found a cap on Digikey
that looks like it will work for you. It's from the same family as the
one Terry mentioned. Part #P10502-ND .0039uF 1600V Metalized
Polypropylene caps. They show 1169 in stock at various prices depending
on quantity. I fired up the MMC helper and it gave the following info
after plugging in the values from Digikey.

Cost: $88.1145
Total caps: 135
15 strings of 9 caps each.
14400 V AC w/ 1.4 DC-AC rating factor
0.0065 uF
C per string: 0.000433333333333

Not bad. I don't know how much you were looking to spend, but pulse caps
for TCs are pricey (see Maxwell for an example). They are well built,
and probably worth the money, but I don't have the cash for new ones,
and used ones of the proper value are rare. You could try ham radio
swapmeets, sometimes you can get a deal there. But they usually know
what they are worth. ;) The MMC is the most cost effective way to get
high quality caps without having to build them ourselves and pour oil
all over them. And I really don't like the whole oil thing. ;) 

You can find the MMC helper program at
http://tesla.better-dot-org/mmc_form.cfm. Digikey is at www.digikey-dot-com. Get
a few spare caps to have arround just in case you get a bad one and it
blows, or you want to add more C later. Personally, I would get 200. At
...65 you can't go wrong. That's about $130. Not bad at all for what you
get. Of course, I don't know your budget for this. And in the end it all
depends on you. Perhaps a group could get together to buy 1000 of them
at .42 ($420) and save everyone some money. 

Travis


Tesla List wrote:
> 
> Original Poster: "Spud" <spud-at-wf-dot-net>
> 
> Yes, there was a typo in my message.  I was looking for normal tank
> capacitors, and I typed .7295uf.  That was supposed to be .007295uf, or
> somewhere around there.  I saw some equations on a site that concurred
with
> what a guy told me in a message that the correct value for a 12/30 NST is
> .0066uf.   So anyway, if anyone has capacitors around that value (or
> anything that would work, I would like to get this thing working sometime
> soon. :)), and wants to sell them, my original plea still stands. :)