Re: Toroid for mains conversion?

On Fri, 03 Jul 2009 12:07:24 -0500, Tim Wescott <tim@xxxxxxxxxxxxxxxx>
wrote:

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.

I found it entertaining... that last ground isolator (Xitel) I bought
used ferrite pot core transformers for audio... and the bass response
is excellent!

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine Sometimes I even put it in the food
.

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