Magnetic Fields, No Current

Hi everyone,

So I've been trying for a while now to bypass the problem of creating an external magnetic field in *other* AC/DC modules; but now I see that in the MFNC there are two options: External Magnetic Flux Density, and the same without external. The External seems to be a pointless node - it does not make any change at all in the model, does not affect anything - and you cannot provide it with any information;

so here's the first question - what does the External Magnetic Flux Density node do?

the other node, without external, seems to work if you have a stationary model, but if you have a time dependent, any field that is not 0 makes it not converge. attached a model; can anyone tell me what is wrong?

I'm working with 4.2a.

thanks,
~Shoval