by ChumpusRex2 » Wed 21 Jun 2006, 07:38:27
$this->bbcode_second_pass_quote('EnergyUnlimited', '
')Possibly slow demagnetisation of permanent magnets will make working mentioned device for certain period of time.
Demagnetisation of permanent magents is pretty slow, unless you can completely overcome their field (with a much stronger magnet).
2 similar magnets, if held in an unstable formation (e.g. 2 north-seeking poles next to each other) will gradually lose their magnetism - but this process will take months. This is why magnets should be stored in a stable position (i.e. north to south, with metal 'keepers' to complete the loop).
Attempting to extract the stored energy in a permanent magnet will likely result in most of that stored energy being released as heat within the magnet, with only a little getting returned to the demagnetising field.
The reason that there is a common misconception that permanent magnets can store lots of energy, is because they can seemingly pick up objects over and over and over again. In fact, this is an illusion. If you hold a magnet over a ball bearing and the bearing jumps up and sticks to the magnet - you are only getting a loan of energy from the magnet. If you want to get the magnet back to its original state, you need to pull the bearing off the magnet - repaying the loan.
I commonly see this idea of magnets 'discharging' as a reason why perpetual motion devices aren't perpetual. I hope I've explained above, why this concept is totally wrong.