Re: Both Terry filter and RFI filter?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Bert Pool <bert.tx-at-prodigy-dot-net> 

For a cheap RFI filter, BG Micro (www.bgmicro-dot-com) has a 3 phase unit rated 
at 30 amps per phase (90 amps if you parallel them) for something like six 
dollars.


At 11:19 PM 5/5/04 -0600, you wrote:
>Original poster: pepperman-at-softhome-dot-net
>When using a Terry filter to protect my transformers, do I also need
>a separate RFI filter to keep the interference out of the mains?  If
>so, what frequency response is acceptable?  I recently looked at
>some commercially available filters and found out that most of the
>units they sold only went down to 150 kHz, although a couple of
>the more expensive ones went all the way down to 10 kHz.
>
>In case it matters, I was looking at filters made by Corcom (which
>was recently bought by Tyco), specifically the B series 20-amp
>model (cheapest series); the series that filters all the way down to
>10 kHz is the T series, but it costs quite a bit more (~$88 vs. ~$23).
>
>I'm building a largish coil (still undecided on some of the specs, but
>it'll be an 8"-12" coil, hopefully around 1.5 kVA), so the resonance
>frequency might be below the ratings of the RFI filters, but I'm not
>sure if that matters or not.  Where does most of the RFI noise that
>we're trying to filter out come from, anyway, and in what frequency
>range?
>
>So, do I need a separate RFI filter, and if so, will bottom of the line
>model work fine, or would it not do much for keeping noise out of
>the mains?
>
>Michael Johnson