Thanks for the link Jim. I'm in the process of digesting the info now.
I assume that I need to wrap all three wires through the toroid (both 120V
legs and neutral). I have a four wire connection from the generator to the
cabin with a separate ground wire. Since I'm connecting to the primary
breaker panel, ground and neutral are connected directly together at the
panel. Should the ground wire also be wrapped through the toroid, or should
it be kept separate? I don't have much practical experience choosing
toroids so any advice is appreciated. I'm planning on 30A of current, but
since the total current is balanced, I suspect that a large core is required
only because of the wire size involved (3 or 4 10-gauge conductors).
Another topic that is regularly debated is whether to have a separate ground
rod at the generator and another at the service entrance to the cabin. I'm
not sure if that will have any affect on RFI or if it is purely a safety
issue. It seems that two ground rods would increase the possiblity of
ground loops which could increase RFI. Any thoughts?
Clay W7CE
----- Original Message -----
From: "Jim Brown" <jim@audiosystemsgroup.com>
To: "RFI List" <rfi@contesting.com>
Sent: Tuesday, March 22, 2005 4:47 PM
Subject: Re: [RFI] Honda Generator RFI
> On Tue, 22 Mar 2005 16:29:10 -0800, Clay Curtiss W7CE wrote:
>
> >For the latter, I'm not sure which cores would be best.
> >I need to filter 30A at 240V.
>
> A good commercial line filter at the generator is probably be a good
> idea. Not all are created equal, so study the specs carefully. You
> want to ground the filter to the generator with very short leads.
>
> As to cores -- they are likely to saturate under load if you put
> them on individual conductors, so plan on putting them on the paired
> cable so that the total field is small (that is, the hot is
> cancelled by the return). Used this way, the cores will attenuate
> common mode radiation from the line.
>
> There is an applications note on my website that you may find
> helpful.
>
> http://audiosystemsgroup.com/SAC0305Ferrites.pdf
>
> Note that the data in this applications note applies specifically to
> small signal applications where saturation and heating of the core
> do not occur. Both will reduce the effectiveness of the ferrite.
>
> Jim Brown K9YC
>
>
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