Performance Estimation of a microwave

[chatelot16]

I have not had the patience to read all the pages ... but there is a problem to compare an electric kettle and a microwave!

in the electric kettle it's simple: the resistance is in the water ... all the heat that makes the resistance goes into the water ... easily yielding close to 100%

in the microwave the first element is a transformer, which does what it can ... its losses are dissipated in the open air, not in the stuff to heat

the second element is the magnetron which also has its losses not in the stuff to heat

then there is where the microwaves go ... there are some who leave in the nature everywhere around ... not too much not to be dangerous but still enough to make the loss

the microwave is not an economical means of heating ... it is especially a practical means of heating to warm up certain things

the microwave is not the worst means of heating: a pan on a gas fire can have an even worse performance

[Christophe]

Found this morning on FB...

Hello,
I have a corrosion problem in my microwave oven, it makes beautiful sparks that are not reassuring at all when it turns.
Anyone have an idea how to stop the corrosion in the yard and patch the holes.
Of course using products that will not make the oven toxic

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I like the "don't make the oven toxic"....

[Exnihiloest]

...
I have a corrosion problem in my microwave oven, it makes beautiful sparks that are not reassuring at all when it turns.
Anyone have an idea how to stop the corrosion in the yard and patch the holes.
...

The holes are slotted antennas, no wonder the sparks. Moreover, the badly conductive rust must absorb part of the energy.
Do not try to repair the sheet, but cover the entire surface with a large aluminum plate in one piece and thin (< 0.5 mm). A sheet of aluminum would be sufficient but too fragile.

[Christophe]

Above all, you have to put this thing in the dumpster if he doesn't want to get cancer within 5 years!

Sorry, but there are limits to the fight against obsolescence anyway...

[Macro]

The kind of guy who has to put patches on his condoms

[Exnihiloest]

 
What a lack of faith in environmentalism! There are limits to repairs but there we are far from it. If the power supply and the magnetron work well, which seems to be the case given the "beautiful sparks", there is no reason to throw everything away for rust holes.
And whoever has a welding station will advantageously replace the aluminum I mentioned with small scrap plates and welding to plug the holes.

That said, I am happy to find defenders of the consumer society where I would have least expected them! You are right, we have to change everything

[Christophe]

Yes yes exni! And will there be no dendrites in the welds?

And if this microwave has turned in this state there is a good chance that the magnetron is cooked!

For the record, I had smoked the first of my parents when I was a teenager by putting... a jar of nutella without removing the protective film which clearly contained aluminum...

In short, I hesitate between consternation, amazement and madness concerning you...

[Exnihiloest]

Yes yes exni! And will there be no dendrites in the welds?

And if this microwave has turned in this state there is a good chance that the magnetron is cooked!
...

I have already answered this point. You need induced KV for "nice sparks", and that's a sign that the magnetron is far from cooked. Did you understand this time?

Aluminum is not a danger, only when the parts are small because they serve as more or less tuned antennas. All metals of small sizes are to be avoided, not only aluminum. And if you have a bit of savvy, you will have noticed that the whole cage is metallic, and even the support allowing you to put one dish above the other. The metal is not a problem since its shape and its dimensions avoid its coupling to the electromagnetic field.

That said, with a lack of knowledge of electromagnetism and less conviction in environmentalism than in the consumer society, we can propose its replacement.

[Christophe]

Except that as soon as there are sparks in an MO it damages the magnetron!!

A nutella jar film is "antenna" because it is not torn on a regular basis! Try it on yours!

I had the case with my microwave that I had to change a few weeks ago: the grill support was starting to lose its chrome plating which was coming off with tiny bits and it was sparking, seen that a posteriori and the magnetron lasted a few weeks and gave up the ghost...

Now it's up to you to use a pierced MO...it will give us a vacation sooner than expected!

[Flytox]

Yes yes exni! And will there be no dendrites in the welds?

And if this microwave has turned in this state there is a good chance that the magnetron is cooked!
...

I have already answered this point. You need induced KV for "nice sparks", and that's a sign that the magnetron is far from cooked. Did you understand this time?

Aluminum is not a danger, only when the parts are small because they serve as more or less tuned antennas. All metals of small sizes are to be avoided, not only aluminum. And if you have a bit of savvy, you will have noticed that the whole cage is metallic, and even the support allowing you to put one dish above the other. The metal is not a problem since its shape and its dimensions avoid its coupling to the electromagnetic field.

That said, with a lack of knowledge of electromagnetism and less conviction in environmentalism than in the consumer society, we can propose its replacement.

Repairing this microwave:
- Machine dismantling.
- Stripping of the sheets of its paint.
- Study of the work to be done.
- Purchase, Cutting / bending of sheets to complete / replace corroded sheets.
- Adaptation of various mechanics, raceway etc...
- Welding of sheets.
- Painting of the sheets.
- Reassembly of the machine.
- Test of the bousin with the instrumentation which goes well in the continuation of the leaks of radiation.

- All this on used gear that has already suffered .... when you find the equivalent new for 60 € with the guarantee that there are no leaks ....
- Ecological treatment also means not lingering / wasting time on dead bodies.