Permanent magnet lifter 1

[vichey]

Will someone please explain how the permanent magnet lifter works. I am particularly interested in how it is possible to turn on and off the the attraction that this lifter has on the material being lifted.

 

[MagMike]

Permanent magnet lifters consist of permanent magnet(s) in conjunction with a magnetically soft material (e.g., Iron). The magnet is fixtured so it can be moved or rotated to bring it into contact with the iron when the device is on; or moved/rotated away from the iron to turn the device off.

There is usually a small amount of attraction from the iron when the device is off, because of residual magnetism. Usually this is not noticable.

 

[Skogsgurra]

You can see this on machine-tools. The table often has a striped structure where steel and brass alternate. The brass stripes are the "parking places" for the magnets underneath and the steel stripes are where the magnets are when the table holds the workpiece.

Magnet feet for measuring dials work on same principle.

Gunnar Englund

http://www.gke.org