Microwave oven magnets and parts

[TheEquineFencer]

I was looking through fellow "scavengers parts supply" and found a lot of old broken microwave ovens. I took one apart and got the two magnets out of it. They were not the exact same size. Just what are they worth? How useable are they and what else is of use out of the ovens? Are there any dangers in messing with these ovens, you know like me starting to grow extra eyes and legs and such?

Thanks, Floyd

[TomW]

Floyd;

Microwaves have a transformer that can be useful or at least most do, switches, various lights and fixtures bits of insulated wire a fan usually and the metal in the case has been used for things. They have a capacitor and diodes in them, too but these are useless for our purposes generally.

Not much cash value but for some a nice batch of "stuff" you can use if resourceful.

Sometimes electronics has capacitors that can store a bit of a charge awhile after unplugged. Usually not lethal but enough snap to make you jump and all thats associated with quick movement in an enclosed space with sharp edges.

I scrapped a few and used lots of the bits over time.

Tom

[wooferhound]

The magnets are Ceramic so their not very powerful. a few of us have made generators from them but the output is poor unless you make a big machine from a large number of the magnets.

[imsmooth]

Any dangers?  If you get a hold of the MOTs (microwave oven transformers) they can be deadly.  They are not current limited, which means if you short the ends or draw an arc they can draw large amounts of current.  Besides being lethal, they can burn out your wiring if it is not properly protected by fuses or breakers.  Also, the ground is the casing, so the transformer body is lethal to touch if it is energized.

[ghurd]

Strange timing.

Here is one of my favorite microwave magnet projects, Joseph WXYZSCIENCE's car alt,

http://www.fieldlines.com/story/2007/7/4/225522/5838

The transformer coils are worth quite a bit at the scrap yard if they are copper, but I wouldn't expend the effort to try reusing it as wire.

The transformer lamination pieces are worth quite a bit as parts (single rotor with laminations), or tools (in the process of gluing down magnets close together) for my tinkering.

Grind off the welds and the disassembly is a lot easier.

A handful of strange switches, fuse holders, bulb sockets, and short scrap wire is handy sometimes.

The aluminum layers between the magnets can be used for heat sinks.  Or scrap (take apart a dozen microwaves anyway, and the scrap value adds up pretty fast).

I even saved a few cases for the sheet metal.

I never gutted a microwave that did not have a resistor across the big caps.

It still makes me a bit jittery, but I never saw one that would not be safe if it was unplugged in for a week.

G-

[kurt]

i used to repair microwaves for a living. that big capacitor hooked to the high voltage side of the transformer all the modern ones have a bleed off resistor across that cap to bleed the charge in the cap to ground after the power is turned off as a safety but if you get ahold of a very old one that does not have that that cap can hold a 4000 volt charge for months after the last time it has been run. low current but very high voltage it has killed people. always make sure the microwave is unplugged and be sure to short that cap with a couple of plastic handle screwdrivers as soon as you open the case just to be sure that it is not holding a charge i have had caps arc on me when i shorted them even in modern microwaves were the bleed off resistor has failed so be careful....

[TheEquineFencer]

The free one I took apart for the heck of it, I saved the PC board, it had a nice display, the magnets and a couple of micro switches. I saw the large CAP and figured it could store a bit of power, I may go back and get it. I was wondering if there was enough copper in the tranformer to be worth the effort.