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Re: [RFI] Power Line Bypassing

To: rfi@contesting.com
Subject: Re: [RFI] Power Line Bypassing
From: Chuck <charlesh3@msn.com>
Date: Mon, 14 Feb 2011 19:28:30 -0800
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>

The problem here is that it is a neighbor's pump so there's not too much 
that can be done at that end.

Considering that it is easier to modify my friend's environment than his 
neighbor's,  what can you say about power line bypassing? Is 1 kV and .1 
uF enough for the caps? Best to go common mode and also each side to 
ground, I assume.

> Message: 1
> Date: Sun, 13 Feb 2011 16:26:22 -0800
> From: Jim Brown<jim@audiosystemsgroup.com>
> Subject: Re: [RFI] power line bypassing
> To: rfi@contesting.com
> Message-ID:<4D5876AE.9080303@audiosystemsgroup.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> On 2/12/2011 9:05 PM, Chuck wrote:
>> A friend tells me he has an AC lines conducted noise problem from his
>> next door neighbor's well pump. In the past, I have heard of people
>> putting bypass caps onto their service entrance panel.Is his best answer
>> to apply bypassing? If so, what is recommended?
> You didn't say what frequency, or what the noise sounds like.  The first
> thing I would work on is making sure that the neutral and green wire are
> not bonded together at the pump. Also make sure that no 120V motors are
> running between one side of 240 and the green wire.  Both are recipes
> for noise. Also, try to figure out what kind of motor and motor
> controller it is.  If it is speed controlled, what kind of controller?
> The best cure for most conducted noise is a good common mode choke, and
> the most effective common mode chokes are formed by winding multiple
> turns of the cable around the "right" ferrite core.  The choke MUST be
> very close to the noise source to be effective.  Conducted noise is
> really RADIATED noise -- the wire that conducts it becomes an antenna,
> so the choke works by killing the current.  You MIGHT do some good with
> caps at the entry panel, but I suspect that the wiring that's doing the
> damage is between the pump and the panel, in which case the caps
> probably won't help.
> For more, study http://audiosystemsgroup.com/RFI-Ham.pdf  Also, study
> the tutorial on Power And Grounding for Audio and Video Systems at
> http://audiosystemsgroup.com/publish.htm   While it's written for those
> systems, the same laws and rules of good engineering apply, and the same
> dumb electrical wiring mistakes cause problems at both audio and RF.
> 73, Jim Brown K9YC

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