DC motor rotor + stator : torque by attraction ?

AI Thread Summary
The discussion revolves around the principles of torque generation in a DC motor, specifically the interaction between the rotor and stator magnetic fields. The force acting on the wire is described by the equation F = B*I, leading to the understanding that the rotor's magnetic field aligns with the stator's field to produce rotation. Confusion arises from the concept of magnetic poles attracting versus the alignment of magnetic fields. Ultimately, clarification is achieved by recognizing that the direction of magnetic flux varies by location, resolving the perceived contradiction. The problem is concluded as solved with a better understanding of magnetic flux behavior.
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DC motor rotor + stator : torque by attraction ? [Solved]

So on that image there's a very simple dc motor.

Knowing that F = B*I, the force acting on the wire can be represented as on the image.
Also the current passing through the rotor will create a magnetic field, represented by Brotor, pointing downards.
Acording to the first image, it will rotate as if the magnetic fields align, because of the F = BI equation, so both magnetic fields would point in the same direction.

TlaMt.gif



On the other hand, here we just have that the opposite poles attract, so the force is for the magnetic fields to point in opposite directions.

Uaml2.jpg


I'm having some difficulty understanding this, because these concepts seem to contradict each other.

1Plpe.png


So where am i thinking wrong here?
 
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Could it be because on the outside the flux of the rotor points upward ?

http://imageshack.us/f/14/asdadfq.jpg/
 
Ok i think I've come to grips to what's causing the confusion.

Since i saw the magnet flux from north to south, i assumed wrongly that South is where the flux vector always points.

But it seems it only points in the direction of the flux on that specific location. So both images are correct and this problem is solved.

magpart3a.gif
 
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