Re: filter (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 9 Nov 2007 06:50:58 -0600
From: David Dean <deano@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: filter (fwd)

On Monday 05 November 2007 09:17:49 am you wrote:
> ---------- Forwarded message ----------
> Date: Sun, 4 Nov 2007 18:51:29 -0800
> From: Clive Hansen <mrclivehansen@xxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: filter
>
> Hello,
>     I was wondering what exactly is needed to build a mains filter? Is it
> simply a filter capacitor, an inductor, and possibly a fuse? If not, how
> can a mains filter be built affordably?
>
> The circuit I am thinking of looks like this (I'm not the best at ASCII
> schemos:
>
> MAINS: 120V 15A   -----FUSE----|------------\                      _____
>
>                                                |_
>
> INDUCTOR----/           >TO 15KV 450VA NST
>                                                _CAP      INDUCTOR----\_____
>                                ----------------|------------/

Hi

See http://www.ibiblio.org/kuphaldt/electricCircuits/AC/AC_8.html for a basic 
discussion of filter design.

Some of the better filters (not addressed in the above link) use a pi type 
filter. They have a high frequency bypass capacitor on the input across the 
line, and a high frequency bypass filter on the output across the load. In 
the middle they have an inductor in series with each leg of the line but both 
of the inductors are wound on a common core in such a way as to provide 
common mode rejection.  Also Known As a common mode rejection transformer.

See http://www.e-sonic.com/aboutus/cat/A/AC%204.pdf for schematics and 
specifications of some of the corcom filters.

My understanding is corcom filters are readilly available at little cost. See 
the concurrent thread on "mains filter".

later
deano