Re: AC & DC field question

["David Meeker" <dcm3c@xxxxxxxxxxxxx>]

--- In femm@xxxx, "alanbabb" <alan@xxxx> wrote:
> Is there a way to model the reslutant field of the AC field of a coil 
> and the DC field generated by a permanent magnet. 
> 
> I have the complete motor structure of a loudspeaker design in FEMM 
> but if I set the problem to have a frequency the permanent magnet 
> drops out. I am trying to model the effects of shorted turns both 
> inside and outside the voice coil in the magnetic gap.

With femm, you can only evaluate the problem at one frequency at a
time. That's why you can't see the PM (because it creates a DC field)
when you do AC analysis.

For what you want to you, you could use femm to identify flux linkages
between your coil and the shorted turns using a series of DC analyses.
You can then use these flux linkages as part of a circuit
representation of your device, which you would have to build
independently of femm.

Dave.