HV PWR XFORMER-gud idea

Brian Carling bry at MNSINC.COM
Thu Jan 22 07:46:34 EST 1998


I heard that this quiescent current draw was due to some
electrico-mechanical loading on the transformers to dampen voltage
variations as the load is applied, and that there are some little
metal pieces that need to be removed.

What are they called?

Does anyone know how to identify these and remove them from microwave
transformers???

Bry, AF4K

On 21 Jan 98 at 16:57, Richard wrote:


> VAN LINCOLN wrote:
> >
> > Heard a couple hams on 2 meters this morning discussing a really good idea.
> > Thought I'd  pass it along on the internet.
> >
> > One of the hams talking said he found that in OLD MICROWAVE OVEN's, was an
> > undiscovered
> > resource.  Namely the HV transformer that powers the Magnetron Tube.  He
> > has observed that
> > most of the transformers have a HV winding of +/- 2000 VAC (single winding)
> > @ usually
> > about 500 ma. capacity.  AND a 110 VAC primary.   This means that two
> > transformers matched of course, and placed in series, will provide 4000 VAC
> > centertapped, and 110vac/220vac primarys AT 1/2 an AMP, which is
> > more than enough to power that linear amp he wanted to build.  Also, old
> > worn out Microwaves can be had
> > for free or very cheaply at service dealers, and the local paper want ads.
> > FYI from a 'fellow junk collector'
> > wd8aam.....this can be copied freely for any use.
> >
>   I have a friend who works in electronics repair and who investigated
> the use of microwave power transformers in amp power supplies....He
> found that they draw a rather high no-load current on their primary
> windings, around 2.5 to 3 amps, depending on the size of the xfmr. You
> can hook up one to 120vac and measure the primary current with a snap-on
> type inductive ammeter--I did and confirmed his finding.  If you are
> willing to allow that much no-load loss they should be usable.
> You will notice that the transformer laminations are welded together,
> and this would increase core losses.
>
> Dick W0EX
>
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AM International #1024, TENTEN #13582. GRID FM19. Using a SWAN 250 on 6m,
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