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I Magnetic field direction on Halbach array?

  1. Aug 2, 2016 #1
    Hi, hopefully someone here can help me! I'm interested in Halbach Arrays and specifically I want to make a circular array in which the field is amplified away from the array (as in above or below it), not to its inner diameter (or exterior circumference).

    Is this possible?
    On the web Ive seen images of wedge/arc shaped magnets making circular arrays but the fields seem to be within the same "plane" as the magnets (inner circle and outer circumference).
    The traditional straight "fridge magnet" 5 cube-magnet Halbach array does what I want but I need it physically in a circle.. what happens if you make the line say 15 cubes long and make it loop around on itself?
     
  2. jcsd
  3. Aug 2, 2016 #2

    mfb

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    Staff: Mentor

    I'm not sure if I understand you correctly, but assembling multiple fridge magnets (or similar) in a loop is certainly possible, and will give a large magnetic field outside close to the ring with a small magnetic field inside the ring.
     
  4. Aug 2, 2016 #3
    Sounds more like you are describing the normal inner/out configuration. I'm looking to do something more like this (though not with the pricey arc/wedge magnets):
    Halbach.jpg

    Id like to build two, with opposing polarities.. I'm now thinking how one "chooses" the polarity of the strong side too?
     
  5. Aug 2, 2016 #4

    mfb

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    Staff: Mentor

    You can form any shape with the fridge magnets or their equivalents. Note that you don't get those large arrows: the field is only notable close to the magnets.
     
  6. Aug 2, 2016 #5
    Thanks... to clarify however Im not using fridge magnets, only mentioned them as they are straight lines vs and arc shaped halbach array. I'll be using N50 cube magnets arranged in circle pattern.
     
  7. Jan 10, 2017 #6
    kodachrome, the array you're talking about should be possible with the correct set magnetic field orientations. What you want are the north and south poles of every other magnet to be facing perpendicular to the array assembly, like an axle going through a wheel, rather than toward the center and exterior of your array structure. So those magnets need to be magnetized in what is known as the thickness direction. Take a look at k&j magnetics for their selection of magnetic segments. You would use the AY0X030-C and AY0X030-T magnets for the array you're describing. The AY0X030-C, AY0X030-S, and AY0X030-N magnets are used for the array you mentioned that you commonly see where the strong field is within the inner circle. Hope that helps!
     
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