17th July 2011 03:25 AM
I could use some advice concerning microwave oven transformers.
I know these MOTS tend to saturate under low load and this causes energy wasted as heat in the primary.
I want to remove the step up secondary and replace it with a 12 AWG step down to about 28VAC. That may require around 28 to 35 turns of wire from general MOT winding data.
My issue is this. I want to reduce the losses due to MOT saturation. I can separate the E and I sections of the core. Would it be acceptable to add a small air gap between the E&I sections of the core to limit the saturation of the core? How would this affect my output....would I need more wire turns etc? I'd like to see perhaps 15 to 20Amps full load output,5 V drop. The MOT is from a 1.2KW microwave. I understand adding more soft iron to the core can also offset saturation. If I build layers of 2 mm thick headless nails (individually dip varnished) stacked to extend the E core, how shall I calc the mass of iron nails I need?
Adding more windings to the Primary may be possible, but it looks kinda tight.
Thanks for any advice.
17th July 2011 12:44 PM
I think that a microwave oven transformer is made as cheap as possible so it is not efficient. The microwave oven is used only for a few minutes at a time and it has a fan so its transformer does not heat much. The core is too small and its primary winding has not enough turns for continuous efficient use.
17th July 2011 04:03 PM
These are informative links
Perhaps a current limiting circuit on the primary may be the solution.
Here's a useful tip:MOT windings =>> 2500 turns on sec and 110 on prim and 4 on the third coil, on a standard US microwave.
Last edited by Mosaic; 18th July 2011 at 03:18 AM.
21st July 2011 04:00 PM
Yes really helpful video that is simple for new maker.
26th July 2011 08:21 AM
Appears to be a good idea
28th July 2011 04:25 PM
Yes, very nice an simple!
29th August 2011 06:10 PM
very nice video. any one can do it
30th September 2011 07:56 AM
Helpful videos ,Really very good
Last edited by The Moderation Team; 30th September 2011 at 10:38 AM.
30th September 2011 11:47 PM
You do a nice job. Both a simple explanation and the hint that it's different as you learn more.
4th October 2011 03:05 AM
That was a very helpful video. Where would you suggest someone just getting into electronics start ?
ac to dc,
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