[Boatanchors] Baking moisture from power transformers

[Al Parker]

Hi John,
	Barbara might not be happy with the possible smell from her oven after 
you do that ;-)  I'd use 150F as a very maximum, and many ovens won't go 
that low.
	Whatever you do, keep the temp down in the 140-150F region, and leave 
it for 24 hrs or more, 46 even better.  There's a big hunk of "heat 
sink" there, and many tiny air spaces to warm up.  It will take a long 
time to drive out the moisture at that temp.
	I've used a 60 or 75 watt bulb in a drop light, under the chassis or 
piece to be heated, blocked up appropriately, and with a makeshift cover 
of cardboard, towels, whatever.
	You can gauge 140F on a dry object if you can put your finger on it, 
but not be able to hold it for more than a cupla seconds.
YMMV
73,

Al, W8UT
www.boatanchors.org
www.hammarlund.info

"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole

On 12/22/2014 11:14 AM, John King via Boatanchors wrote:
> I have  a plate power transformer that has been stored inside the shop and not exposed to moisture other than the normal high humidity of the Louisiana climate. I would like to be sure that it has not absorbed sufficient moisture from the inside atmosphere to endanger its' likely of developing a short.
>
> I am considering baking it in my wife's (K5MOL's) kitchen oven. I am interested in your experience with residual moisture removal from stored transformers. I have read somewhere that 150 degrees  might do the job without damaging the insulation. What temperature have you used and for what period of time? Your input based on experience or referral to the information on the internet will be appreciated.  Thanks and 73, John, K5PGW
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