Metcal autosleep stands - how do they work?

[PaulAm]

I've been looking for a bit trying to find out how the Metcal autosleep stands work without any luck.  Anyone have a clue how they work? I need a stand for a DS1 desoldering handle and I'm not enthused about paying out the list price for one. 

[mikeselectricstuff]

There is a pair of magnets in the stand that saturate the magic alloy to stop it absorbing energy from the RF coil

[smashedProton]

^^ called a curie point

[PaulAm]

Thanks, that was the clue I was looking for.  One magnet doesn't do it, but with 2 fairly strong magnets I can get the tip temp down about 150F. 

[Signal32]

Thanks, that was the clue I was looking for.  One magnet doesn't do it, but with 2 fairly strong magnets I can get the tip temp down about 150F.

Any tips on how to get the tip to idle at 60C ?
I'm using STTC tips and even with the genuine MX-W1AV workstand, they idle around 150C.
I've tried 2x strong neodymium magnets but I seem to be unable to get it below 120C.
How did you position the magnets ?
Thanks.

[Assafl]

^^ called a curie point

I thought curie point was due to temp only. In the case if the very strong Neodymium magnets used by Metcal - I think the mechanism is saturation of the energy absorbing core. Hence the eddy currents the form are much lower.

Furthermore, since the eddy currents are lower, the voltage rises and the generator reduces power to the coil. So it actually messes with the power delivery feedback loop and causes it to drop power.

[grifftech]

Hall effect sensor in the the iron and magnet in the stand

[Monkeh]

Hall effect sensor in the the iron and magnet in the stand

There is no sensor in a Metcal iron.