Andrew VK3BFA wrote:

John - KD5YI wrote:

Tim Wescott wrote:


Using 1/2 wave rectification on each one will result in big DC currents
in the coils. These DC currents will saturate your cores like nothing
else.



Hey, Tim -

IIRC, there is only one diode attached to the transformer in my microwave.
That would mean it is half-wave rectified as it comes from the factory. Yes?

Cheers,
John


No. Its actually a full wave voltage doubler - the tube itself is used
as a diode.
And there not, strictly speaking, "proper" power transformers - a
saturable reactor would be a better description. They use this to
current limit the things cheaply - notice the big "Boing" when they
switch, noticeable on a low duty defrost cycle.

I read an article years ago on using them for powering linear amps --
the first thing you were supposed to do was knock the shunt out of the
core. Apparently this is usually quite easy unless it's spot welded, in
which case it's quite hard.

73 de VK3BFA.

PS - as a self employed electronics technician, working alone, I refuse
to work on the things in my business - too many people been lethally
zapped by them, and no one nearby to give CPR......

This could be wise -- once you broach the case on one of those things
you're into voltages that will deal instant death. But that's the case
for just about any tube linear amplifier.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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