|[AMRadio] Has anyone seen one of these?|
k4kyv at charter.net
Tue Jul 29 00:10:07 EDT 2008
> From: BILL GUYGER <bguyger at sbcglobal.net>
> ... What someone did was to try to make their own high(er) power
> modulation transformer. There was a roughly cubical metal box with a fiber
> board top. The top had 5 terminals mounted to it for the primary and
> secondary connections. The top mounted to the box with 4 sheet metal
> screws, and by the time I got it after it had sat in a garage in Waco for
> 40+ years the fiber board was soaked with oil.
> I opened the top and found a 50-60 watt Stancor Mod. transformer sitting
> on a piece of 1/2 " plywood with cardboard pieces packing the rest of the
> box. There were also bits of steel stock that looked like machine shop
> scrap because they had been turned. The whole thing had been filled with
> transformer oil (which had turned to gelatinous goo) and a couple of holes
> had been drilled in the covers of the Stancor transformer to allow oil to
> fill its innards.
> I'm guessing that this might have been something that was sold in one of
> those little ads in the back of QST or some such. I'm also guessing that
> the metal pieces packed into the box along with the transformer were
> supposed to enhance the magnetic properties of the transformer somehow.
I suspect whoever put that modulation transformer together added the metal
pieces to enhance the weight, not the magnetic properties, and sold it,
claiming it was a higher power transformer. The guy who built the rig
probably never suspected that he didn't have a bigger transformer.
But it's a good possibility that even with the oil, that the unbalanced DC
saturated the core of the transformer.
I once used a swinging type filter choke that was rated at 5/25 henries, 500
milliamps, but only 600 volts. I took it out of its case and submerged it
in a can of pole pig oil and used it in a 2500 volt power supply until I was
able to find a choke rated for the voltage. The submerged choke never
crapped out and I used it for over a year.
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