[Hammarlund] Transformer baking Recovery

[roy.morgan at nist.gov]

Quoting Rbethman <rbethman at comcast.net>:
>...
> Most of us have power, mod, audio, and "other" transformers that have
> been "due to storage requirements", exposed to humidity.... 
> My Electric stove/oven has a 200 Deg F setting.
> 
> I plan to make some baking runs on xfmrs for periods between 2 to 4 hours.

Bob and others:

One of the most desirable Heath audio amps (the WM-5, I think) is subject to
very high incedence of power transformer failure. I suspect dampness in the
potted-in-tar transformer.

Especially in the case of potted transformers, I'd think that a couple of days
would be better. 2 to 4 hours may only get the insides partly warmed up.

A short trip to the home store would get you an electric heater thermostat, a
sheet of 3/4 inch aluminum covered house insulation board, and a couple of
flood lights.  Rig up a modest size drying box and let it run.  With a small
inlet hole and outlet hole, you'd get modest circulation and keep most of the
heat in so it would be lit up only some of the time.

Well insulated leads to use the megger from outside would let you know  how you
are doing. Monitor the resistance till it raises to a fairly level reading and
then double the time.

Sooo many projects, sooo little time, but this one seems like a good one to
reduce losing some of those old trannies that might short out if not dried
out.

I have to wonder if the reported leakage in SP-600 chokes could be reversed with
such treatment.

Roy
K1LKY

Roy Morgan
13033 Downey Mill Road
Lovettsville VA 20180