Re: [femm] Boundary conditions of induction motor

[dcm3c@xxxxxxx]

In a message dated 10/18/2001 6:03:45 AM Eastern Daylight Time, albertoperarnau@xxxxxxxx writes:


> Hello,
> As you know I'm simulating induction motor with femm, thanks for your answers. Now I have a doubt with boundary conditions. I want to make smaller my region of problem, I use antiperiodic boundary condition as you say in your manual to simulate one pole of motor, my motor has six poles. I  haven't problem with magnetostatic simulation, but I have problems with harmonic simulation, in this simulation there are two poles, one imaginary and another real. My problem is that I don't know where I have to put boundary conditions, I attach a word document, in this document is drawn place where I think that they must go boundary, is correct?


Well, the drawing that you attached looks like a four-pole machine rather than a 6-pole, but the idea is right.  That is, apply antiperiodic to the edges of a 1-pole simulation and periodic to the edges of a two-pole simulation.  The BC works OK for complex currents.  You can think of the real part and imaginary parts as representing snap-shots of the currents at different instants in time.  At any one instant, you've only got one actual pole, although in terms of complex number, "there are two poles, one imaginary and another real."

Hopefully, I haven't muddied the waters further....

Dave.