Re: Transformer from a microwave oven

"Engineer" <fakeaddress@xxxxxxxxxxx> wrote in message
news:WYqdncvGH9VOIsfeRVn-qg@xxxxxxxxxxxxx
> Hi, all...
> This may seem an odd post but I'm an avid re-user and recycler of
> old and/or scrapped electronic stuff (especially tube equipment), so
> I hope all will be clear...
>
> I have just picked over the carcass of a dead microwave oven (free
> junk from a church sale) to get a thermal switch to repair our main
> unit, but that's another story...
>
> I pulled out all the usable bits (not many!) but also the power
> transformer.

(snip)

Some informative, if depressing, replies. Thanks for all.

Firstly, since posting I knocked out the magnetic shunts and rechecked
the secondary voltage. It's now 2000 VAC (off load) for 120 VAC in, a
ratio of nearly 1:17.

Of course, John (two of you, other one from "tubes" NG) is right about
these shunts, regulation is worse. I was confusing them with that
resonant CVT design that uses a capacitor and magnetic shunts in a
weird way. Mea culpa. <g>

That's a good point about the insulation at the frame end (Roger L.),
it's not good for 2 KV but, in other uses, it may not have to be.
Anyway, I'd decided not to push it very far but thought it would be
quite safe at normal tube B+ (DC.) However, from the tube NG, Phil
said the LF and HF response would be very bad. I could readily agree
the HF would suffer from the crude winding layout but figured that, at
a couple of watts, the LF would be OK - lot of iron! Anyway, impedance
match is impossible and the matter of DC in the core is yet another
problem for SE amps and P/S chokes.

The more I think about it the more it looks like a door stop. Too
bad...
Thanks again,
Roger


.

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