[FEMM] Impedance of Voicecoil

[Scott Diehl <Scott.Diehl@xxxxxxxxxxxx>]

I'm trying to model the so-called "blocked" impedance of a loudspeaker voice coil at various frequencies.  Up to now, I've always modeled a wound coil as a single conductor/region and set the current equal to the number of Amp-turns.  I also set the conductivity of the voice coil material to zero to eliminate eddy current effects in the coil (that would be eliminated by the layers of insulation).  Doing this, however, effectively invalidates the impedance results from FEMM.

 

I never worked with bulk laminations in FEMM, but I thought that I might be able to fool FEMM into eliminating the eddy currents while maintaining the conductivity of the coil.  After attempting this, I found that horizontal laminations are not supported in axisymmetric AC models.

 

The only other alternatives I can think of are to model each turn as a separate region or try to take the zero conductivity results and include DC resistance.  Has anyone found a better way to model blocked impedance in FEMM?

 

Any insight appreciated,

Scott