Core selection

Damn, I like that. You'll, or no wait, Jan :) will have to send me some PICs. Then I can put them across this transformer's secondary and see what happens. >:-D

Tim

Perhaps nobody has experience in this field? I tried the same thing you are doing for low power stuff. As someone already typed before: there are a huge amount of units which need to be converted and each vendor seems to have their own specification method. Its a world of pain.

That leads to the question: why do you want to wind your own transformer? It might be much easier to have a transformer wound which meets your specs than failing a couple of times. At the power levels you are talking about, a failure is likely to cause collateral damage.

If you are serious about winding your own transformer I think you might need to buy some cores first put some windings on them and verify your calculations. Beware that the method of winding also influences the behaviour of the transformer.

I'm not too concerned about that (which, you're right to observe, seems kind of odd given the ten kilowattedness of my ambition). I've done this plenty of times before- junk ferrites are plentiful, but small. The biggest cores I have are probably worth 2kVA together (and that at 100kHz). Testing saturation and inductivity is easy, making transformers is easy (especially when they have only ten turns). I really just need the core to do it.

Getting a transformer wound feels like a huge waste of resources, seeing as I just need the core (whichever size it has to be). I don't need someone else to design it (assuming I get the correct core), and I don't need someone else to wind it -- do winders even do 1/4 or 3/8" copper tubing? -- I can do all that myself, no need to quadruple the price of this project on services. Consider, BTW, that I am of the age group where "money is short and time is free". ;-)

That should also not be a problem, about five turns of copper strap around the toroid with one pipe down the center would be pretty fine I think. If I need several turns secondary, I can either wrestle the pipe through, or cut it into segments and fix it back together with fittings (compression or flare, I'm thinking). The extra connections won't do any favors for conductivity, but oh well.

Whereas, I suppose if I bunched all the primary turns to one side of the toroid -- which is tempting, stiff as that copper strap is -- that side would be more prone to saturation, which might produce unfavorable results (sooner saturation, higher LL, etc.?).

Tim

No it's not safe to conclude your calcs are right--I didn't check them.

Here's Terry Given's take on a similar app, complete with worked out examples and wisdom of the ages:

HTH, James Arthur

Well, it's just the kind of treatment PICs deserve, but no, I won't buy some to send you one.

OTOH I'm trying some interesting things with the AD uCs (AD702x), those mainly because AD knows how to make ADCs and DACs, but the other peripherals are somewhat limited in their possibilities and they could have looked at the Atmel's AVRs and got some inspiration.

On a sunny day (Mon, 11 May 2009 15:31:04 -0700 (PDT)) it happened Tim Williams wrote in :

Yea, I thought about melting some PICs together to do the one turn loop thing, _LONG_ before you did. But I rather leave melting PICs to religious anti PIC fanatics :-) I like my PICs, keep good care of them usually.

On a sunny day (Mon, 11 May 2009 18:47:16 -0700 (PDT)) it happened Tim Williams wrote in :

I have seen put stacks of ringcores on top of each other for RF work. You could make a tower of the largest ringcores you can get?

Have not tried myself though... YMMV.

I was thinking about something like that, - bend copperpipe in a U shape, stack toroids on each leg, thread primary through the cores.

I guess if you wanted to make it fancy you could make two plastic plugs to fit inside the stacks to keep the pipe in the center and arrange the primary turns nicely around it.

-Lasse