I had a Panasonic microwave with a switching power supply... It caught fire
and all the high pressure smoke came out. Bought it new and it lasted about
1.5 years. The power supply was extremely noisy. Bothered every
communications receiver in the house. Even the 2.4 GHz wireless network. The
new GE microwave is 100% quiet. No noise at all. Doesn't even bother the 2.4
wireless network.
73
Jim W7RY
----- Original Message -----
From: "Jeff Blaine" <keepwalking188@yahoo.com>
To: "Hsu" <hsu4qro@gmail.com>
Cc: <amps@contesting.com>; "Herzog" <herzog@frontiernet.net>
Sent: Wednesday, March 11, 2009 8:34 PM
Subject: Re: [Amps] microwave transformers
> 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.
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>> _______________________________________________
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>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>
> _______________________________________________
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>
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