jim rozen wrote:
In article , Don Foreman says...

It isn't about current connected from windings to lams. It's about a
closed conductive path enclosing the time-varying flux in the core.
Any closed conductive path enclosing the flux linking the winding is
a shorted turn.

Yep. Try that sometime, put a turn of coat-hanger wire fully through
a core sometime, with the ends connected.

Back when transformers were new, they had all kinds of tricks.

A****er Kent made them by winding the bobbin on a form, and then
slipping it over a bundle of steel wires. Then bend the wires
over to overlap to complete the flux circuit. Pot the whole thing
in tar and there it is, laminated core without the need to punch
the E and I pieces.

Jim



step-lap cored transfomers are interesting too. They wind the core out of strip steel, then cut it apart,
and reassemble it around the coils. They're really efficient and used in distribution transformers.