RM told me that Panasonic has a new HV switching PS for microwave ovens
in production now. And that a couple of those may make a decent light
duty B+ source. Not sure if he was joking or not. I do suppose the day
will come eventually where heavy metal for tube amps may be a thing of
the past...
73/jeff/ac0c
Hsu wrote:
> I had ever to contact with a microoven transformer manufacturer,the list
> price for 1000w microwave oven's only $10/ea. the core not hypersil and the
> the wire's material is Al,Not Cu.
> 73!Hsu
> ----- Original Message -----
> From: "Herzog" <herzog@frontiernet.net>
> To: "Ham-amps" <amps@contesting.com>
> Sent: Thursday, March 12, 2009 9:06 AM
> Subject: [Amps] microwave transformers
>
>
>
>> RE: Dittos from all I have learned about MOTs about the only thing
>> they will
>> do correctly is run a microwave oven. They have too few turns in the
>> primary
>> so the transformer runs hot and lossy, the magnetic shunts limit output
>> current
>> and the welds along the edges of the laminations act like a big shorted
>> turn,
>> so the transformer runs hot and lossy. The transformer pulls several
>> hundred watts just idling with no load. Did I mention they run hot and
>> lossy?
>> They were built with one thing in mind - maximum cheapness.
>>
>> It is a shame because they look so tempting to use. But for all the work
>> and aggravation of trying to rebuild them, grinding off the welds
>> across the
>> laminations, knocking out the magnetic shunts, possibly adding turns to
>> the
>> primary, you might be much better off to just buy some laminations and
>> build your own transformer. Plus you will learn something by building
>> your own transformer and it is fun!
>> =================================
>> How about putting two transformers, with the primaries in series, and
>> the secondaries in parallel.
>> Or if need more use 4, two primaries in series, then in paralleled.
>> The whoole microwave is just too cheap to not use them; unless space,
>> etc is the object, not just price. K 2 L B.
>>
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>>
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