|MadSci Network: Physics|
When two magnets are forced together, their magnetization may diminish over time, or it may stay the same. This depends greatly on how strong the magnets are. If you take a strong magnet (what is termed a “hard magnet”) and place its north pole next to the north pole of a weaker magnet (termed a “soft magnet”) the soft magnet’s magnetization will then decrease and eventually change to match the magnetization of the hard magnet. The amount of time that is required for this change depends on how well the domains in the soft magnet are aligned. The reversal occurs because the direction of magnetization of the individual domains in the soft manget begins to change in order to match the net magnetic moment of the hard magnet. Of course, this is a simplified explanation. To learn more about these processes, I would recommend consulting “The Physical Principles of Magnetism” by Allan H. Morrish or the following PDF document available online to learn more about the basic principles of magnetism (http://www.qdusa.com/resources/pdf/FundPrimer.pdf). I don’t know much about the two devices you spoke of (the Minato Wheel and Perendev device). From what I was able to learn, it appears as though simple magnetic forces are used to drive a motor (http://www.kindtimes.com/action/content/viewnews.cgi? id=EplkEulpVAzZVHajZo and http://www.freeenergynews.com/Directory/Perendev/Magnet icMotor/KeithAnderson_statement )for both devices. If the magnets used are permanent magnets (that is, hard magnets) and the magnetic forces they are subjected to are not extreme, then in theory the strength of these magnets maintain their magnetization over time. In practice, though, heating causes magnets to weaken over time, and I would guess that the same would happen in these motors and so the devices would have some useable lifetime after which the magnets would need to be replaced.
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