Electromagnetic force
Electromagnetic force
(OP)
I know this is a basic question, but I cant find an answer in literature that match the units I have measured. I have a magnet whos strength is measured in Gauss. I have a set of electromagnets with known number of turns, size of wire, AC voltage and current. The electromagnets face each other so that the field lines flowing out of one flow into the other. If the magnet is placed in the feild of the electromagnet, it will want to move perpendicular to the feild lines. The question is, how can I calculate the force that makes it want to move.





RE: Electromagnetic force
RE: Electromagnetic force
RE: Electromagnetic force
The force is then the derivative:
F = dE/dx (or -dE/dx)
Where E is the magnactic energy function of the displacement x
RE: Electromagnetic force
I'm have a hard time imagining your geometry. You have two permanent magnets with a gap and flux flowing between them. If the permanent magnet is on a pivot directly between two electromagnets, then it will want to align with the lines of flux - N toward one and S toward the other. Then when polarity reverses it will want to align the other way.
I am just guessing at your geometry. Pls explain more.
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RE: Electromagnetic force
the web sites for a vendor of BLDC motors. Been too long,
but I think it was a white paper on rotor design. Surf around.
<als>
RE: Electromagnetic force
electricpete, there are no rotating parts in this assembly. There are two e-core electromagnets facing each other. In the gap between the two faces are a pair of permanent magnets suspended by two rubber diaphragms so that they can only move translationally along an axis perpendicular to the electromagnetic feild. The N and S poles of the permanent magnet are parallel to the electromagnetic feild lines and are not allowed to rotate as the field changes direction. This is not an issue as the dominant force is attempting to move the permanent magnets perdendicular to the electromagnetic flux direction and it only reverses, never changes angles.
spargher, I agree a derivative will be more accurate and I didn't think about the energy relationship. I've been looking for a Force equation. I really only need an average and a peak value but if I have to integrate, so be it. It will be nice to have a good plot of whats going on in there. Thanks.
RE: Electromagnetic force
In any case, it's going to be a tough road to come up with a force. I don't know the units used to express strength of permanent magnets.
This might be a good post for the Magnetic Engineering forum.
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RE: Electromagnetic force
I have found the following vector equation: F= q*v X B where q is a charge on a particle in Coulombs, v is the charge velocity vector in m/s, and B is the electromagnetic flux vector in Gauss. Because this is a vector cross product, the force will be at a maximum when the charged particle (permanent magnet) is moving along a vector that is perpendicular to the lines of electromagnetic force. The problem with all this is that the permanent magnet's strength measured in Gauss, not Coulombs. Is it possible I have lost my mind and that B is the MAGNETIC flux and that qv (which is coulomb*meter/sec or Amp*meters) is the ELECTROMAGNETIC force? Could the A*m be simply the Amps flowing through the coil multiplied by the length of wire in the coil? That would make it easy, too easy. It also doesn't match what little literature I've found which says that q*v is the charge and velocity of the moving permanent magnet and B is the electromagnetic flux. There are reasons I am not an electrical engineer, this is one of them. I thank you all for all of your help.
RE: Electromagnetic force
RE: Electromagnetic force
TTFN
RE: Electromagnetic force
RE: Electromagnetic force
Gunnar Englund
www.gke.org
RE: Electromagnetic force
TTFN
RE: Electromagnetic force
RE: Electromagnetic force
RE: Electromagnetic force
RE: Electromagnetic force
Again thank you all for all your help and any other thoughts you may have.
Lem