DIY Magnetic Chucks

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DIY Magnetic Chucks

Post by Scratch » Mon Jul 22, 2019 3:13 pm

So after yesterdays bump about "eliminating C-clamps" and building electromagnets from microwave transformers, I did a little bit of research. I also removed the 3 transformers from my junk microwaves.
I was happy at how easy they were to remove from all 3 microwaves first of all. I just removed the main cover and the bolts were all easy to access. No need to dig into the deep depths of the microwaves.

But I was super happy at how easy they were to turn into electromagnets! The only hard part was removing the primary winding, and that wasn't too bad either! I even got them to work great using one AA battery! I put one battery on it then stuck a small piece of metal to the magnet. Then I used a flap disc grinder and a wire wheel grinder on it pushing real hard, and the piece never moved. And that was with one AA battery! I also had a double battery bucket and hooked that up and it worked even better.

Then I hooked it up to my 18V drill battery and was shocked at the pull it had! Way more than I needed but still super cool!

My question is has anyone gotten these to work as small part holders and how did you power them?
Convert AC to DC with some extra electronics?
Just use Drill batteries?
Stick with a couple toy batteries?

What about wiring? My AA setup wiring never got warm, but my 18V battery made my wires start to get warm and I'm not sure the best way to go about keeping them from getting too hot.

Any input?

Here's some pics, and if you want my advice... PULL THAT TRANSFORMER BEFORE YOU TOSS THAT MICROWAVE!

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Re: DIY Magnetic Chucks

Post by weldguy » Mon Jul 22, 2019 4:01 pm

This is the coolest thing I have learned here in a long time. Wow what a genius idea! I suppose a DC power supply would be a solid permanent solution to the batteries. So cool :Like :Like :Like

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Re: DIY Magnetic Chucks

Post by acourtjester » Mon Jul 22, 2019 4:50 pm

3 boy am I jealous :HaHa :HaHa I only have one. I think most use standard 120 Volts AC as that is what the primary coil is designed for.
You may end up with a stronger one with DC, maybe an old computer power supply +5 volts. You can hook a switch between the green and a black wire in the power supplies wire harness as a on/off switch, many YouTube videos show that. :Like
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Re: DIY Magnetic Chucks

Post by Francisco » Fri Aug 09, 2019 5:15 pm

Just seen this. Two points:

1) An electromagnet only runs on DC. Some gear briefly allows AC to run through the coils, after the DC is cut off, to quickly demagnetize the poles and allow for easy material removal.

2) Those microwave secondary coils are just a few turns of largish copper conductor. Resistance will be very low. Feed them with 127 VAC and the magic smoke will get out, probably not just from the coils. Don't do it.

So, measure your Ohms, do your math, use a stepdown transformer and a rectifier bridge, and protect with a fuse.

A 12V car battery charger may be the ticket, depending on the coils' impedance.

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