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Re: wondermagnets



Original poster: Jim Lux <jimlux-at-earthlink-dot-net> 

At 07:24 AM 3/11/2004 -0700, you wrote:
>Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
>
>Hi Steve,
>
>I friend of mine has a magnetron (in his basement). I think he said the 
>magnet was about 1 Tesla.  The Magnets from the store seem to be "rated" 
>at 1.2 Tesla.  So I would guess they are about the same but the Magnatron 
>electromagnets in general covers more area.  His machine is also very 
>small compared to some.
>
>Cheers,
>
>         Terry


Flux - (Weber (Volt second) ) (in CGS, Line or Maxwell)(Capital 
Phi)  (compare Current)

Flux Density (magnetic induction) - Tesla (Weber/sq m), Gauss (CGS) 
(Capital B)  (compare current density Amps/square meter)

Magnetomotive Force - Gilbert(CGS) Amp-turn (SI), (compare to Voltage)

Magnetic field strength (Magnetizing force)   - ampere/meter (no SI unit) 
(Oersted CGS)) (Capital H) (compare E field Volts/meter)


mu (permeability) = B/J  (Gauss/Oersted) (Tesla/(amp/meter))

In an electromagnet, as you put more magnetic field (i.e. by cranking up 
the current in the coil around the material) into something, the flux 
increases until it reaches some maximum, and then the flux can go no higher 
(around 1.8-2T for iron/steel)

Some materials ("hard") will still have flux, even after the field is 
gone.  You can then put an opposite field on it and the flux will steadily 
decrease.

So.. that magnet rated at "1.2 Tesla" actually means that at some place, 
the field is 1.2T.