"John Larkin" wrote in
message ...
big ****ing snip
One of my engineers, a real magnetics guy who used to work for Signal
Transformer, designed a push-pull forward dc/dc converter using a pot
core. This was in the power supply of a laser controller [1] where the
customer, for reasons never rationalized, wanted our +24 power to be
isolated. One center-tapped winding included a half turn on each side,
and efficiency was terrible. Going to full turns, and wasting a bit
more power in a downstream linear regulator, worked much better.
Neither of us understood why.

Well that's obvious, it's acting like two transformers. Huge LL between
halves. Imagine the full path of each turn, it's effectively a full turn
around one outer limb or the other, but not both.

Whether or not you curve it tightly around the center limb doesn't matter,
intensions are lost on inanimate objects.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms