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Re: The right capacitor match?

Original poster: "Mark Broker" <mbroker@xxxxxxxxxxxxxxxx>

The CDE 940 series are not really suitable for TC applications. They are a metalized film construction, which makes for very weak electrode/lead wire connection. Therefore they tend to fail due to over current. An oversized MMC with 940s will likely work just fine, as I'm sure some will attest to. But the best capacitor to look for is the CDE 942 series. These are well-used and well tested. A string of 13 2kV, .10uF caps will work, as will 10x 2kV .068uF caps. The MMC made with the .10's will be more robust but will cost more.

Richardson's Electronics seems to be the best place to buy them, though they have a minimum order. Some on the list may have a dozen to spare, though :)

Cheers!

Mark Broker


On Tue, 02 Aug 2005 22:29:09 -0500, Tesla list <tesla@xxxxxxxxxx> wrote:

Original poster: "Ethersmith" <siveya@xxxxxxxxxxxxxx>

Greetings,

New coiler here, hoping to find some aid.

I have a 15K/30mA NST which I am building an MMC for.

Given LTR of 1.5* I have come up with a match in the range of .008mF

I have had trouble finding HV caps in the lower Farad range. (Any current
suggestions would be greatly appreciated).

I have found some Cornel Dubilier (940C30S47K) "Snubber Capacitors" that
look like they will work. They are not on Terry's known Bad Caps list. They
are rated at 3kv .047mF

If I have done my math properly, I only need six of these in series to get a
capacitance of .00783mF (which is in my LTR range) and a voltage of 18,000v
(which exceeds my NST voltage)

This seems small and cheap compared to what others seem to need regularly.
Is it just that my coil is one of the smaller ones out there? Or have I made
some egregious error?

Your input is golden.  Thank you.

--Ethersmith