Toroid for mains conversion?

You'd best take those efficiency figures with a grain of salt, also any claims to permissible operating flux level differences attributed to the structural differences alone. Efficiency is something you can pay for, but are unlikely to be more willing to do so than anyone else.

Any road - if your concern is with audio frequency transformers, as stated elsewhere, efficiency will hardly be your first consideration.

RL

tify

Keep telling yourself that. There is an obvious need you have to get people to believe you and believe you are a genius. This is a sign of insecurity. We are all insecure but some of us are intelligent to deal with it properly.

Phil is well known, and mentally ill. You are wasting your time arguing with him.

Some old monochrome computer monitors used them as well. It allowed them to use a smaller & thinner case.

Switchers are getting more common as they get cheaper and include PFC. The great advantage is the continuous 100-240 volt input range.

I buy a PF-corrected Mean Well 150 watt switcher (48 volts DC out) for about $38. Has all the UL and CE stickers. No failures so far. I can't buy a 150 watt toroidal transformer for that, much less the rectifiers, caps, line-voltage-switch stuff.

John

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.

"John Larkin"

And the dopes.

I've got one in a low voltage lighting fixture. The only reason I can see for its use is that it provides a somewhat lower profile than would a 'standard' configuration core.

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

Afraid of switchers? Lots of people are.

One project I want to do would series 8 of the 48-volt switcher outputs to make a 400 volt supply. All I need is a customer for it.

John

Phil's problem is not ego, it's some sort of mental illness. He actually knows a fair amount of engineering, so cut him some slack.

Cheers

Phil Hobbs

if

In the bad old days when I had to work for a living I had a rule of thumb for power transformers.

That's ARRL type stuff... and true.

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

Bob

I know that, for some reason, European consumers LOVE toroidal transformers in products... Enough so that they might gravitate towards a product with a toroid xformer rather than one with-out a toroidal xformer.

Since theyre tape wound, you don't have the round the corner magnetic grain path problem that you do with E-I lams. Maybe that's why ? But how would they even know this or care much ?

You still have to get the wires out of the windings... This is where they tend to "leak", field wise AFAIK.

bob