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Re: NST Filter and Circuit Configuration?
At 20:45 19/12/98 -0700, you wrote:
>Original Poster: Terry Fritz <twf-at-verinet-dot-com>
>
>Hi Ed, Travis, and All,
>
> I thought I should mention something about the stress on the filter
>resistors in RCR filters to clarify why they can easily fail if the
>elements cannot dissipate heat quickly as in most wire wound types. This
>will illustrate my concerns:
Snip.....
Lack the theory but would have to agree. Initially used R-C-R filter with
1.1k R elements made from 3 x 3.3k 17W wire-wounds, giving a nominal rating
of 50W.
Boy, did these get HOT !!
Now use 6 x 17W to get 1k and have them mounted on some spare heat sink,
which appears to be a much better arrangement ...... just be careful how
close you have the wire ends to the heat sink ..... I'll say no more ;-)
cheers
Mark
http://www.cobweb-dot-com.au/~dkfinnis