Can anyone explain how the problem of eddy currents addressed in the
last line of the first comment
of......https://answers.google.com/answers/main?cmd=threadview&id=162668

....is mitigated when the inventor says "The magnet will be one of the
current neodymium rare-earth permanent magnets with an energy product
of up to 45 MGOe and a residual flux in excess of 11,000 gauss. Common
cold-rolled steel will serve as the flux guide because eddy currents
will never complete their path in that metal
(http://www.inventor1-y2k.com/newpage4.htm)"


The problem of eddy currents in the last line is: "However moving the
shield into position is going to be dampered by eddy currents.   So
the energy required to move the shield is going to be greater than
energy generated by the device."