Re: wondermagnets

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi Jim,

At 10:23 AM 3/11/2004, you wrote:
>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.

I barely have "electric" fields figured out, let alone the magnetic stuff %:o))

So a 1.2T magnet could be the size of a car, or the size of a pin head...

I don't think anyone here wants to haul an electromagnet like my friend's 
half way across the country and then wedge the monster into the 
basement.  But they make pretty darn big NdFeB magnets and you can get a 
LOT of them ;-))  Probably best for a spark gap.  Also there has always 
been talk of using small coils in series with the primary to take advantage 
of the 1000 amps there too...

I think the NdFeB magnets are the strongest out there that a normal person 
can get and afford.  So they would seem perfect for the gap thing.

Cheers,

         Terry