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Re: EMI filter hookup
Original poster: "Mike Novak by way of Terry Fritz <twftesla-at-uswest-dot-net>" <acmnovak-at-email.msn-dot-com>
It seems to me your EMI filter died doing it's job. I guess all that RF
finally caught up with it... Slap a purple hearton it and buy a new one.
Corcom filters can be bought for approx. $5 surplus, so don't fret. I don't
think anyone should disconnect their filter just because it could die,
because they're cheap (compared to your entire house circuitry). I seriously
doubt one could say that it fed more RF back into the house without some
My .0002304 Cents,
> Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> Last week I changed several components on my coil which required that I
> experimentally retune it. I was perhaps 1-2 minutes into this tuning when
> performance suddenly diminished, the circuit breaker tripped, and a
> smell filled the garage. It turns out that my 30 Amp Corcom EMI filter
> toasted. I had been using this filter for well over a year with no
> and I'm sure that my 15/60 NST was not pulling more than 20 Amps.
> I examined the hookup and came to the conclusion that one or more of the
> filter's internal caps had been over-volted by the hookup configuration.
> had connected the filter "backwards" as is frequently suggested, with the
> LINE side connected to the NST primary. The 3rd wire ground from the wall
> is not used anywhere in the coil beyond the variac so I was connecting the
> RF ground to the filter's case instead.
> I now believe that in a configuration where the filter is located at the
> where no 3rd wire ground is available, that the "backwards" configuration
> inadvisable and was responsible for the failure of my filter.
> I've added a page to my web site with schematics illustrating the good and
> bad ways to hook up the filter. I don't know if I'm the only person who
> in that backwards configuration with the RF ground, but hopefully I can
> someone else's filter from toasting.
> Oh yes, it also appears that in addition to being self-destructive, that
> configuration also made the EMI fed into the household wiring worse than
> no filter was used at all!
> The new page is at: http://people.ne.mediaone-dot-net/lau/tesla/emifilter.htm
> Regards, Gary Lau
> Waltham, MA USA