hi folks;
first i've to excuse me about my lack on english language (german preferred), but...
i've some questions about neodym-magnets;
1.) when mount a neodym-magnet into a coil and pulse this coil with electric pulses (on-time about 0,1-5ms) in the opposite magnetic direction.
- will this "hurt" the neodym-magnet and decrease the magnetic strenght permanently (i'm not asking about the loss of high temperature)
- how fast will the natural magnetic field be destroyed
- how to calculate the coil using 12V-supply to solve such a field (formula?)
2.) as shown in several videos (magnetic motor and more) there are some static magnets and rotating magnets. when the rotating magnets move across the static magnets, there will be a magnetic friction. any mechanical friction results in temperature. does the magnetic friction also raises the temperature of the moving magnets too?
mike
I am far from being an expert but I have been studying these matters a lot lately (you would love to know why, but I can't tell ;) ) and I feel I can give it a try at least for the first two of them:
Quote from: mike-ao on September 18, 2008, 11:17:13 AM
hi folks;
first i've to excuse me about my lack on english language (german preferred), but...
i've some questions about neodym-magnets;
1.) when mount a neodym-magnet into a coil and pulse this coil with electric pulses (on-time about 0,1-5ms) in the opposite magnetic direction.
- will this "hurt" the neodym-magnet and decrease the magnetic strenght permanently (i'm not asking about the loss of high temperature)
- how fast will the natural magnetic field be destroyed
- how to calculate the coil using 12V-supply to solve such a field (formula?)
2.) as shown in several videos (magnetic motor and more) there are some static magnets and rotating magnets. when the rotating magnets move across the static magnets, there will be a magnetic friction. any mechanical friction results in temperature. does the magnetic friction also raises the temperature of the moving magnets too?
mike
Nd magnets as considered to be "hard" magnets, as the they require a considerable force to be moved trough their BH curves. As long as they are not taken too far from their retentivity or saturation points (which would require a tremendous magnetic force opposed to them), the Neos will be ok. Also, don't heat them if you want to keep'em "healthy".