Re: Toroid for mains conversion?


"Tim Wescott" <tim@xxxxxxxxxxxxxxxx> wrote in message
news:_YadnRd3E8hRp9PXnZ2dnUVZ_h1i4p2d@xxxxxxxxxxxxxxx
On Fri, 03 Jul 2009 13:41:48 +1000, Phil Allison wrote:

"Dorothy with the Red Shoes on"...
"Phil Allison"


I saw a site once that said toroids were much more efficient

** False.
The percentage efficiency of similar rated E-cores and toroiodals is
the same.


They are less leaky.

** ??????????


It stands to reason that any difference, even if too small to consider
major, would be in favor of the toroid.

** For the same VA rating, percentage efficiency ( under load) can go
either way, by small margins.

The subject is MAINS power toroidals BTW.

And toroids are a pain in the ass to wind. Even if you have a machine
doing it, it's still a pain in the ass because the machines require a
much greater degree of care and feeding than a simple wire winding lathe
putting turns on a bobbin. (You can figure this out on your own if you
consider what the machine has to do. I used to know a guy who had to
maintain both types, and the toroid-winding machines were _always_
broken).

So: you get an itty bitty bit more efficiency -- maybe -- and you have to
deal with much more finicky machines on your production line.

This probably explains why there are a few toroidal mains power
transformers out there, but not a whole lot of them.

--
www.wescottdesign.com

Isn't the object of a torroidal transformer greater isolation and less
radiated energy?

Bob


.

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