3 ms·

That can provide shielding, but how does that turn off the permanent magnetic field when a human considers working on (maintenance or decommissioning) the machi

• jacquesm 4y ago
  Well, during decommissioning that would be a tricky thing to do, but during maintenance I could image a way to slide the mu metal in front of the magnets shunting the field away in a safe way. But you are right, working on such gear requires strict precautions and attention to safety detail. Let me give you one example of how hard it is to work with these: while building the windmill I had decided on an 'inside out' model where the rotor rotates around the stator, this has a bunch interesting properties, such as pushing the magnets onto the drump while they rotate instead of trying to eject them from the rotor in the normal designs. And because magnets get hot any kind of glue or other adhesive would be subject to all kinds of thermal stresses, might let go or melt. So that was a pretty neat solution. My rig for installing the drum was a half ton crane over a very heavy steel workbench that had the stator mounted to it. As I lowered the rotor suddenly the whole assembly, table and all lifted off the ground and perfectly centered itself around the rotor. I swear I never ever saw that one coming and it really scared the crap out of me because only minutes before then I was still fiddling with pushing some wires in place inside the stator while the rotor was already floating above it. A bit earlier and I could have easily gotten pinched, in spite of all my precautions.