[ARC5] [Milsurplus] Old Dynamotors- Don't be a DooFuss Like Me....

[Dennis Monticelli]

Another trick that works is to apply DC current to the primary in a
sufficient amount to heat the interior via the temp rise of the windings.
 Put several watts into it and let it sit for a day or more.  Proportion
the current to the size of the transformer.

Dennis  AE6C


On Mon, Apr 1, 2013 at 7:09 AM, J. Forster <jfor at quikus.com> wrote:

> For years, I've always baked out stuff with non-hermetic magnetics.
>
> I put the thing on a few bricks, put a couple of 100 Watt incandescent
> lamps underneath it, and a big cardboard box with some holes in the top
> over it, and let it sit for a week or more.
>
> You want the thing to get up to about 130F for several days, at least.
> Longer is better, IMO.
>
> YMMV,
>
> -John
>
> ==============
>
>
> > On Mon, Apr 1, 2013 at 12:50 AM, David Stinson <arc5 at ix.netcom.com>
> wrote:
> >
> >>
> >>
> >> I thought about putting the whole thing sans end bells into a 200-degree
> >> oven for a couple of  hours to dry it out
> >>
> >
> > This is  a problem with big chunks of iron in old transmitters, too. Many
> > do not realize how similar to a sponge the laminations and windings are.
> > And old transformer left sitting in a damp cellar or storage shed is an
> > accident waiting to happen if you just haul it out, hook it up, and apply
> > voltage. Might happen in 5 seconds, 5 hours, or 5 days, 9.9999 times out
> > of
> > 10 it'll zorch.
> >
> > The oven works great as is provides a means of getting rid of the
> moisture
> > without introducing more. On bigger pieces it can take a day or two,
> maybe
> > more, to feel safe enough to put power to it. And there's never a
> > guarantee, of course. But recovery rate is far, far better when dried out
> > than when not. The trick is to heat it up long enough for the heat to
> > reach
> > the core and drive out the moisture. It's all about the mass. Smaller =
> > faster; hours vs days.
> >
> >
> > A good reminder as many of my dynamotors are out in the garage here in
> > humid NC. Though lately humidity has been amazingly low.
> >
> > ~ Todd,  KA1KAQ/4
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