[Boatanchors] Need magnetic shield for shaded pole motor

[hwhall at compuserve.com]

 Thought I used to see soft iron recommended for magnetic shielding. Was that obsolete thinking or just a bad memory at work?

 

Wayne
WB4OGM


-----Original Message-----
From: Brian Clarke <brianclarke01 at optusnet.com.au>
To: rbethman <rbethman at comcast.net>; Boatanchors @ Mailman <Boatanchors at mailman.qth.net>
Cc: james.liles <james.liles at comcast.net>
Sent: Fri, Jan 3, 2014 3:43 pm
Subject: Re: [Boatanchors] Need magnetic shield for shaded pole motor

 
 
 
Silver-plated copper is good for E-field attenuation, but 
approximately useless for H-field attenuation. For H-field 
attenuation, you need high permeability steel of a thickness dependent 
on the frequency and the amount of attenuation desired. See any 
standard text on EM shielding, eg Ott.73 de Brian, VK2GCE.? 
Brian Clarke 
BE, MBA, PhD, CPEng, FIEAust 
MD, Clarke & Associates P/L 
 
----- Original Message ----- 
From: "rbethman"  
To:"Boatanchors @ Mailman"  
Cc: 
Sent:Fri, 03 Jan 2014 15:26:20 -0500 
Subject:Re: [Boatanchors] Need magnetic shield for shaded pole motor 
 
 On 1/2/2014 9:23 AM, james.liles at comcast.net wrote: 
 > Any ideas for an effective Gaussian shield for an open frame shaded 
 
 > pole motor or a source for very high permeability transformer core  
 > uncut sheets. 
 > 
 > Thanks for any ideas--- Kindest regards Jim K9AXN 
 Jim, 
 
 I see your address in QRZ. I have what may be precisely what you 
need. 
 
 Would two sheets of silver plated copper expanded mesh, 13" x 13 " x  
 0.009" do the encapsulation of this shaded pole motor? 
 
 Bob - N0DGN 
 
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