For planning purposes, one must keep in mind
that 'balancing out' the strong influence of 60 Hz
AC flowing in lines that they wish to 'filter' that in
a 240/120 V '2-phase' configuration (with neutral)
that *minimum* current flows on the neutral line
at the service drop/gen when the load:
a) is across the 'outer' lines (240 V) supply lines or
b) is equally balanced between each of the two 120 V
lines (to neutral).
Other factors such as motor-starting (LRA - locked
rotor amperage) and motor running current draw (lagging
power factor) will change this 'balance' too, as will
non-linear loads like power supplies, et al.
Jim P / WB5WPA /
----- Original Message -----
From: "Jim Brown" <jim@audiosystemsgroup.com>
To: "RFI List" <rfi@contesting.com>
Sent: Tuesday, March 22, 2005 6:47 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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>
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