Date: Fri, 24 Mar 2017 15:47:35 -0400
From: Markus Vester <markusvester@aol.com>
To: rsgb_lf_group@blacksheep.org
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References: <1571552606.20170324191313@gmail.com>
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Subject: Re: LF: Stacking toroids
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Yes Chris, this will work. Doubling the core cross section will halve the f=
lux density, and reduce the per-core dissipation by at least a factor of fo=
ur. The improvement may be more if the flux was so high that losses were do=
minated by hysteresis (up to a factor of 8).

73, Markus (DF6NM)=20


-----Urspr=C3=BCngliche Mitteilung-----=20
Von: Chris Wilson <dead.fets@gmail.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 24. Mrz 2017 20:15
Betreff: LF: Stacking toroids


Hello LF people,

 If I have a ferrite toroidal output transformer for a push
 pull Class D 136kHz amp, that gets warmish after a WSPR15
 session, what would happen if I wound the same number of
 primary and secondary turns on two cores stacked together,
 all else remaining the same? Would it run cooler, but
 retain its transformation ratio, or would other things
 occur to make it not that simple? Thanks.

--=20
Best regards,
 Chris 2E0ILY mailto:dead_fets@gmail.com
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<div style=3D"font-size:10pt;font-family:arial,helvetica,sans-serif;color:b=
lack;"><div style=3D"color: black; font-family: arial,helvetica,sans-serif;=
 font-size: 10pt;">Yes Chris, this will work. Doubling the core cross secti=
on will halve the flux density, and reduce the per-core dissipation by at l=
east a factor of four. The improvement may be&nbsp;more&nbsp;if the flux wa=
s so high that losses were dominated by hysteresis (up to a factor of 8).<b=
r><br>73, Markus (DF6NM)&nbsp;<br><br><br>-----Urspr=C3=BCngliche Mitteilun=
g----- <br>Von: Chris Wilson &lt;dead.fets@gmail.com&gt;<br>An: rsgb_lf_gro=
up &lt;rsgb_lf_group@blacksheep.org&gt;<br>Verschickt: Fr, 24. Mrz 2017 20:=
15<br>Betreff: LF: Stacking toroids<br><br></div>Hello LF people,<br><br>  =
          If I have a ferrite toroidal output transformer for a push<br>   =
         pull Class D 136kHz amp, that gets warmish after a WSPR15<br>     =
       session, what would happen if I wound the same number of<br>   prima=
ry and secondary turns on two cores stacked together,<br>            all el=
se remaining the same? Would it run cooler, but<br>            retain its t=
ransformation ratio, or would other things<br>            occur to make it =
not that simple? Thanks.<br><br>-- <br>Best regards,<br> Chris     2E0ILY  =
                  <a href=3D"mailto:dead_fets@gmail.com?">mailto:dead_fets@=
gmail.com</a><br><br><br></div>
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