Date: Mon, 27 Mar 2017 13:30:28 +0000 (UTC)
From: John Fisher <johnfish837@yahoo.ca>
To:  <rsgb_lf_group@blacksheep.org>
Cc:  <jrusgrove@comcast.net>
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Subject: Re: LF: Stacking toroids
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Hi Jay,

Can you recommend a way to compensate for the doubled inductance?

Also, I'd be interested in two driver boards if you get more made.

Thanks,
John
VA3VVV


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On Sat, 3/25/17, jrusgrove@comcast.net <jrusgrove@comcast.net> wrote:

 Subject: Re: LF: Stacking toroids
 To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
 Received: Saturday, March 25, 2017, 7:32 PM
 
 
 Chris
  
 Your original post describes the core as
 "warmish" after a WSPR session ... maybe some
 clarification of what temperature "warmish" is
 would be helpful. A core that runs 'warm' should not
 be cause for great concern ... most core materials can
 tolerate even moderate heating just fine. 'Hot',
 on the other hand, would of course be another matter. As
 pointed out in an earlier post, some of the heating may be
 from losses in the copper windings.
  
 One disadvantage to stacking cores (keeping the same
 number of turns) is that the winding inductance doubles
 from the original design. This will likely increase the
 leakage inductance ... one negative effect being an increase
 in switching transient ringing.  
  
 Jay W1VD  WD2XNS  WE2XGR/2
  
 p.s. I'm looking into getting more driver boards
 made ...