Author Topic: microwave oven transformer as autotransformer  (Read 2122 times)

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Offline jonovid

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microwave oven transformer as autotransformer
« on: November 26, 2016, 02:11:54 pm »
1000w microwave oven transformer as a autotransformer project

here is a 1000w microwave oven transformer taps at 120v 220v 240v  LT 18v  the deadly 1kV HT  I cut this off.
3 hrs of grinding & cutting. this is posted as a demonstration of how removing transformer windings can be accomplished without cutting the Core. shell or damaging other wingdings on the transformer.

at first I cut a gap in the winding so it can be moved back 5mm with a wedge and a hammer. then I use a hack saw to cut off the end now that its 5mm out from the core with less of a cross section for cutting. then i hit it with a power drill to take out some of the winding inside the core, before using a hammer and screwdriver to punch the remaining bits of winding out of the core. I will post more on this. do not know if anyone goes to this much work. just to re-purpose a used microwave oven transformer?  ;D
have not run it as the 1kv winding was too dangerous.  not yet tested it like this.  as I need to wire it up in a safe place .

update
did not have a insulation resistance megger test. 
AC test no load at the wall is 250v.  - 110 tap is 121v, and 220 tap is 226v,  19v is the two little lift tabs, and the red LT is 3.5v .
little humming sound.  :-+  next is to gut an old PC ups power supply for its case
update
the transformer is now mounted on a base plate from a steel case before wiring it up .  shown with a 5Amp circuit breaker, but still has some missing parts.
the used ups power supply base plate has its own plastic  feet.
update
Project completed successfully  :-/O its up and running,  now looking for more space on the bench.  ;D
« Last Edit: December 03, 2016, 05:49:40 am by jonovid »
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Offline jonovid

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Re: microwave oven transformer as autotransformer
« Reply #1 on: December 03, 2016, 05:56:24 am »
project completed :-+
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Offline edpalmer42

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Re: microwave oven transformer as autotransformer
« Reply #2 on: December 03, 2016, 07:24:36 am »
Nicely done!

I've seen some videos on Youtube that used a microwave transformer as a spot welder.  All you'd need to do is wind the new secondary through the holes in the core.  It only takes two or three turns of welding cable.  You could get even more value out of your unit.

 
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Offline jonovid

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Re: microwave oven transformer as autotransformer
« Reply #3 on: December 03, 2016, 10:40:31 am »
totally unaware of just how many others on YouTube, have re-used microwave oven transformers the same way as I did.
lack of forum interest is now understandable.  :palm: 

Your right,   ;D Yes this project has more as a spot welder. .....or maybe high current DC power supply with car alternator diodes.
as the front panel is un-used
 
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