[RFI] Mains filter for test bench

[Christopher Brown]

A filer example is the Corcom 10ED1C EIC inlet filter.

2x .36MH "Z wound" inductor on H-N, and a .28MH inductor on the ground lead.



On 11/7/12 6:09 PM, Christopher Brown wrote:
> 
> Actually there are EMI filters that do filter all conductors.  They are
> EMI only filter bricks (not surge/emi outlet strips).  I have multiple
> examples here of sealed filters with one or more inductors on the
> "green-wire".
> 
> Just not common.
> 
> 
> Now, of we are talking Surge/EMI outlet strips, I have never seen a
> product for sale that filters ground lead.  Only place I do see it is
> commercial grade "EMI filter only" stuff.
> 
> 
> 
> On 11/7/12 3:53 PM, Jim Brown wrote:
>> On 11/6/2012 4:38 PM, Missouri Guy wrote:
>>>  From what I've read, there's some question of whether or not to
>>> run the grounding wire, along with the "hot" and neutral
>>> wires, through a say, a 2.4"i.d. #77 mix toroid.   There are no other
>>> grounding conductors at the test bench.
>>
>> Even the best power line filters provide NO attenuation of common mode 
>> noise on the AC line, because the green wire bypasses the filter.  
>> (While power filters SAY that they attenuate common mode, they define 
>> common mode differently than we do (they define it as noise between 
>> neutral and green, while the proper definition is a signal that is 
>> common to all conductors on a cable).  AND -- most RF noise on the AC 
>> line is common mode noise, and lots of baseband noise is power-related 
>> leakage current on the green wire.
>>
>> Thus, the ONLY good defense for RF noise on the AC line is a serious 
>> ferrite choke formed by winding all three conductors around a #31 
>> toroid, using as a guide  the measured data for single conductors in 
>> appendix one of http://audiosystemsgroup.com/RFI-Ham.pdf
>>
>> For baseband (power-related) noise, the best defense is bonding from 
>> chassis to chassis of all equipment, AND fixing any missing or improper 
>> bonds of the green wires inside equipment. The proper connection of the 
>> green wire is directly to the chassis or shielding enclosure, never to 
>> the circuit board first. Another common mfg error is a chassis 
>> connection that fails because there is paint between the chassis and the 
>> connection lug (VERY common in Astron power supplies).
>>
>> 73, Jim K9YC
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