Does anyone know the approximate thickness/wire guage
of the standard MOT primary and secondary windings?
I've taken a few apart and noticed they're all about the
same between brands, but manufactured in korea. I don't
speak korean, the long-distance charges are prohibitive,
and doubt they have an American wire guage chart handy.

 

If you have taken them apart, then you have the wire to look at! You can go to an electrical/electronics parts supply house and get a "feeler" gauge that will tell you the aproximate size of the wire. Your other option is to measure the diameter of the wire, convert to mils or cmils and look it up on an AWG chart.

 

Measure the diameter of the wire.
This URL will tell size, max amperage and has a calculator for resistance of a length of wire.
http://www.powerstream.com/Wire_Size.htm

 

Can you tell us why..?
I'm surprised you managed to get one apart. Most of them have a strip of weld across the laminations to stop noise, and to Tamper proof them.

 

Obviously I have the wire to look and feel, but that doesn't tell
me the thickness. If I had a micrometer handy and knew how to
read it, i wouldn't need to ask.

Why: because it's handy wire for my project.

MOTS are no problem to open up with a surface grinding wheel
on an ordinary hand drill.

 

If you are unable or unwilling to measure the wire, then we can't help. There is no rule saying that all transformers must be wound with x gauge wire. Sorry.

Might I suggest cutting a small piece off, and going to a hardware store or electronics store, and compare your wire with the marked rolls of wire at the store? You could see which wire yours looks closest too.

Other then that, I guess you could put a variable load on it, increase the current until the wire melts, then take a wild guess by seeing how much current it took, and derating that by a few percent, and.... Yeah, anyway.

 

The closest "electronics" store is 30 miles drive, local hardware store
clerks hardly carry wire guages, and obviously you haven't cut open
many MOTS because yes, they are the same. I thought I might
meet someone here with more experience than myself who might
know. Guess not.

 

First, no one here is attacking you. Calm down. All those of us who have offered suggestions have done so sincerely. I couldn't say "I have a piece of wire in my hands, someone tell me what size it is..." and expect an exact answer. We have done our best to help you help yourself. Sorry if that isn't good enough for you.

Second, by going to the hardware store I didn't mean ask a clerk who has a wire gauge in their pocket to measure it for you, I meant you could visually compare the wire to the rolls that most hardware stores have for sale, and then find a roll that is about the same diameter as yours and look at the label, and see what gauge that is!

While some transformers you find may be the same, I simply meant that not every transformer HAS TO HAVE the same wire gauge in them, it will vary from time to time, brand, wattage of microwave, etc. You may have opened several transformers that happen to be the same size, but it doesn't mean all of them will be. I may open a dozen eggs and find only one yoke in each, but that doesn't mean that I will never open an egg and find a double yoke!

For my final suggestion: Why don't you figure out the load that was on the secondary of the transformer? The wire won't be rated less then can handle the load, and probably, due to costs, won't be rated much higher then the load. That will give you enough information to know what types of projects you can use it on.

You seem to be the expert here, why don't you tell us what size it is? If you have worked on electronics so long and know so much, you should be able to recognize wire size by sight! What size does it look like? Or is this your first time handling wire?

Again, not trying to attack you. I just don't feel you are justified in your complaint against this forum when we have offered our own time with no compensation from you to help you. Free advice is worth what you paid for it! You paid us nothing to solve this problem, so don't complain when we can't help you.

I sincerely wish you luck in your quest to learn Electronics, it is a great field. May you find someone else who can answer every question you pose.

 

I'm not mad or upset but you seem a little defensive. Of course
the advice offered is free. I do it myself when i can help, "give
& receive" sorta' a universal law. I've got a dozen MOTs and
they're all the same wire size (industry standards.) Reverse-
calculating based upon wattages, isn't close enough for
matching inductance values on coils of different turn ratio/
diameters. I never said I knew everything but i know somethings.
I also keep my moth shut out of courtesy when i don't know
the answer.

 

One way to measure the wire is to cut or unwind a turn or two of wire from the transformer, both primary & secondary windings if accessable, take the samples to a local tool & die or machine shop. Most would be happy to "mike" the wire for you. Then, knowing the wire diameters, you can visit the URL thet mrmeval mentioned previously & get the wire gage no., ampacity, etc.

 

Maybe you can try winding 10 or 50 tight turns of the wire side-by-side on something, measure the the total lenght and divide by the number of turns, that could be close if the wire isn´t too thin, like 0.1mm and such.