Strength of a permanent magnet

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Discussion Overview

The discussion revolves around the strength of permanent magnets, specifically addressing how magnetic field strength is measured, the effects of combining magnets, and the implications of their orientation when stacked. The scope includes conceptual clarifications and technical reasoning regarding magnetic fields and their behavior at different distances.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the meaning of the scalar strength of magnets, suggesting that the magnetic field's magnitude should vary depending on the measurement location.
  • Another participant notes that flux density is measured at the magnet's surface and varies with distance from it.
  • Some participants propose that coupling two identical magnets together (North to South) would approximately double the strength of the magnet at large distances.
  • It is argued that while coupling increases strength at large distances, there may be little change in the magnetic field at short distances, with variations depending on the location.
  • One participant claims to have tested stacking disk magnets and found that the field strength at the face of the magnet does double when two are stacked.
  • A different viewpoint suggests that stacking should be done with North to North orientation, as North to South might cancel the fields.

Areas of Agreement / Disagreement

Participants express differing views on how the strength of combined magnets behaves at various distances and orientations, indicating that multiple competing views remain without consensus on the correct approach or outcome.

Contextual Notes

There are unresolved assumptions regarding the specific configurations of magnets and the conditions under which their strengths are measured, as well as the dependence on the type of magnets being discussed (disk vs. bar magnets).

evouga
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Permanent magnets are advertised as having some scalar strength, say, 1.5 Teslas, depending on the composition of the magnet but not its volume. I'm confused about what this means. Shouldn't the magnitude of the magnetic field vary depending on where you measure it? And if I epoxy together two equally-oriented magnets, I would expect that the magnitude of the magnetic field, at a sufficient distance from the magnets, would be approximately twice the strength of that of one of the magnets alone.
 
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Flux density is measured at the surface of the magnet and varies with the distance from the surface. For more info, visit the magnet FAQs at

wondermagnet.com
 
Yeah if you coupled two identical Magnets together North to South you would approximately double the strength of the magnet.
 
Coupling two magnets together increases the strength at large distances where the magnet looks like a dipole, but not at short distances. Near a face, or at a distance
d<L, there would be little change in the magnetic field. It could be slightly larger or slightly smaller depending on the location.
 
The field strength at the face of the magnet does about double by stacking two magnets together. Just did a simple test with some disk magnets I have to confirm this.

The reasons is that the flux will be channeled in the magnetic susceptible material and therefore will add together.
 
I thought you were talking about bar magnets. It is correct that disk magnets would add.
But I think they should be placed N to N. Placing them N to S should cancel their fields.
 

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