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Reduce magnetic radition from motors

  1. Oct 25, 2007 #1
    Im building a small car, that should be able to navigate/drive arround on it own. The short version of my problem can be stated as: 2 DC motors, 1 compas ;)

    The two DC motors are PWM controlled, and dispatch magnetic noise all arround. To be able to work with my compas, I would like to reduce the radiation as much as possible, but what is the best ways of doing this? And is it even possible to reduce it enough to be able to use the compas? The motors runs at 12V, and there is a fairly amount of space around the motors

    Kind regards
  2. jcsd
  3. Oct 25, 2007 #2


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    It is possible.
    You need to shield the motors with mu-metal or some other material with high permeability. In many cases plain iron (not steel) works quite well but it might not be enough here.
    Mu-metal is unfortunately quite expensive and difficult to handle; if you e.g. bend it you have to heat-treat it before it can be used. If you are lucky you might be able to find a company that sells an "enclosure" that you can use directly.
  4. Oct 27, 2007 #3
    Thank you for your reply. I must look up in some material tabels then.
    I was wondering... As the material that will be used will be magnitized, it will also have a magnetic field (right?)

    That would imply that the best solution is to keep the shield as close to the motors as possible (and as far away from the compas as possible).

    I ask because it is possible to just put a flat piece of metal over the motors, and then just use this for a platform to build the other eletronics on...
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