Lab equipment thread. Right now I'm working on building

>>1110410
Does anyone know how I can build the magnetic component, without having it destroyed by the heat? The heat has been destroying the magnetism

>>1110413
Big magnet with high curie point, relatively far away from the heating element. Or just a magnet with high curie point, if your maximum temperature is reasonable.

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>>1110413
More insulation with a stronger magnet. Pic related is a screenshot from one of nurdrage's videos on his hot plate stirrers. Hope this helps

>>1110433
I didn't know it was called the Curie point. Thanks. It looks like neodymium magnets might be a good option for me

Now this is interesting. What else can you do?

>>1110410
You know you can buy those right?

>>1110455

Neodymium have one of the lowest curie points.

You could forgoe the magnet alltogether and just use coils of wire.

>>1110410
>>1110413
are you fixing an old one or making one from scratch?

if your making one from scratch you can attach the magnet to the center of a computer fan and vary the speed by varying the voltage with a POT. you'll have to cut off the blades of the fan but that isn't hard.

A couple things to note:
1. you can find all sort of computer fans with different RPMs and size. Pick one that is in the region of RPMs you're interested in.
2. The voltage vs RPM relationship isn't linear at all (unless you get a special computer fan).
3. In order to get low RPMs from your computer fan you have to give it a jump. So if its normal voltage is 5V to spin it 5000RPM then but you want it to spin at 400rpms then you'll need to give the fan a initial voltage of 5V or enough to get the fan to jump out of the dip in the magnetic field of the dipole's in the brushless motor. You can do this by getting a large capacitor and let it decay to the voltage that you want. I say a large capacitor because you'll need a decay constant of about a 1 second in whatever RC circuit you end up with. Basically you need a large enough capacitor to spin past the pole's resistance to get it started like early airplane rotors.