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Re: Reducing Self Resonance In Rolled Caps
Hi Malcom,
Original Poster: "Malcolm Watts" <malcolm.watts-at-wnp.ac.nz>
>Hi Reinhard,
>> Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net>
>> I hate to blow your dreams, but been there, done that => doesn´t
>> work for long. Building a rolled poly cap (whether it be extended
>> foil design or not) and getting it to run w/o oil WON`T work. Period.
>It can be made to work. I produced a design which increases the
>creepage distance between plates to as good as infinity. The design
>was published in Electronics World in 1995. However, air running
>gives the caps a limited lifetime which can be quantified quite
>accurately (I got about 40 minutes total runtime before the plastic
>gave up in each cap I built).
Well, that is kind of what I meant. I tried your design and it turned
out to be one of the better types. But I, too, had problems with
the air (ionization, etc) and lifetimes of 40 minutes (my best time
was around 65 minutes, using a slightly different config) are not
quite what I would call reliable ;o)). Sometimes, I actually cooked
out the plastizers in the PE, which in turn would turn yellow and
harden. For a reliable cap one would need to go really low on
the voltage per layer (and cap), making it unpractical (esp. if you
are a high voltage coiler ;o)).
>I agree that MMCs are the way to go however.
Yes, I think it is a true milestone in TC technology ;o))
Fantastic article BTW. I had the joy to read it in 1997. Terry
has it on his website somewhere, I believe.
Coiler greets from Germany,
Reinhard