[AMRadio] Drying out HV transformers / Chokes

G. TAYLOR wb8bem at yahoo.com
Sun Sep 18 10:22:03 EDT 2005


I suspect they may not be very wet if they haven't been in contact with
water or condensation. I bought a CVM-5 that had been in an outside
shed that was hit by a tornado. It was rusted, there was a roof over it
but hardly any walls left. Any driven rain would have gotten on it, and
it was in high humidity.(Alabama) But since they are so rare, I bought
it anyway. 

Upon checking, it had about 1-2 megs to ground. If I'd needed in then,
I'd probably tried it at that level. One meg. per 1,000 volts used to
be the rule. But I put it in my basement Ham Shack in Alabama and it
set there in the dry for about a year. I kept checking it and it
steadly was going up. When I was ready to use it, for my HB 810's x
810's it read infinity! No heat, not anything but a dry heated and
cooled basement!

They should be checked with a megger though, It applies a DC voltage
usually 500, or 1,000 volts. Most electricians, or any motor shop has

Gary WB8BEM/8


> 	Ok, I know this has been covered here before, but is there a
> consensus on how to get the moisture out of HV plate transformers and
> chokes, so they won't arc on me.  And before everyone jumps in with
> the
> quick 
> "just put it in an oven on xxx degrees for yy hours", I am working
> with
> the
> iron from a Broadcast transmitter, specifically, the Gates BC-1G so
> these
> things are 100, 150 lbs each, and my XYL would REALLY not like it if
> I
> tried
> to put them in her fancy oven.  They have been sitting in an
> un-conditioned
> but dry hanger/garage for several years, so I am certain they have
> soaked up
> a good deal of moisture over that time.
> Thanks for any suggestions,
> 	Don - W8HRQ
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