[Prev][Next][Index][Thread]

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



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. :)