labview1958 Posted February 14, 2006 Report Share Posted February 14, 2006 I have rotated a smal disk magnet above a large square magnet while measuring the force between them. For one 360 degree turn, I get a "dc" sine cuve. Why does the force change during rotation? Anyone? Quote Link to comment Share on other sites More sharing options...
GAHD Posted February 14, 2006 Report Share Posted February 14, 2006 "dc" sine curve? meaning it goes from force to no force to the same force?Don't you mean AC(alternating current) where the force goes from positive to nothing to negative?If the latter it's because the poles of the magnet each are toa different side and youre alligning and disallinging them as you turn it. If the former and you've got the poles as aligned as you can guess at, my guess would be that one or both have a just ever so slightly tilted magnetic pole from their symmatry point.Hope that helps, but maby you could explain your experiment a bit more: how are you measuring, what's your exact setup, materials? Quote Link to comment Share on other sites More sharing options...
labview1958 Posted February 14, 2006 Author Report Share Posted February 14, 2006 I have placed the large square magnet on the pan of a weighing machine accurate to 0.0001g. The small disc magnet is attached to a actuator/stepper motor and rotated in steps for a full turn(48 steps). The sm all disc magnet is about 2 cm above the centre of the large square magnet. For like poles(repulsion) the amplitude is lower than for unlike poles(attractive). Quote Link to comment Share on other sites More sharing options...
GAHD Posted February 15, 2006 Report Share Posted February 15, 2006 check the magnets allignment, it sounds to me like one or both the poles are tilted in relation to the physical plane of the magnets. Quote Link to comment Share on other sites More sharing options...
GAHD Posted February 17, 2006 Report Share Posted February 17, 2006 And I'm just verifying: you are shure the magnet attached to the stepper is far enough away not to suffer interfearance from it? Quote Link to comment Share on other sites More sharing options...
C1ay Posted February 17, 2006 Report Share Posted February 17, 2006 I have placed the large square magnet on the pan of a weighing machine accurate to 0.0001g. The small disc magnet is attached to a actuator/stepper motor and rotated in steps for a full turn(48 steps). The sm all disc magnet is about 2 cm above the centre of the large square magnet. For like poles(repulsion) the amplitude is lower than for unlike poles(attractive).How much does the large magnet weigh without the other apparatus nearby? That value is the zero in your force fluctuation, not the zero of the scale. Quote Link to comment Share on other sites More sharing options...
labview1958 Posted March 20, 2006 Author Report Share Posted March 20, 2006 The magnets are far away from the stepper. Thus no interference. The large magnet is about 50 grams. The weighing machine can take 200 grams. I am trying to verify whether rotating a magnet such a way should give a constant force or a slightly varying force reading. Quote Link to comment Share on other sites More sharing options...
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