Re: [femm] Linear induction motors

[Dave Squires <djsquires@xxxxxxxx>]

Just to set the record straight. I did not write the FEMM program.
It was written by David Meeker. Just want to prevent confusion.
And I am no expert in using FEMM either. I have learned quite a bit
and can do some things, but that is far from "expert" level.

Dave Squires

Jose Roberto Camacho wrote:

> To: femm@xxxxxxxxxxx
> From: Dave Squires <djsquires@xxxxxxxx>
> Date sent: Sun, 30 Jul 2000 09:39:31 -0700
> Send reply to: femm@xxxxxxxxxxx
> Subject: Re: [femm] Linear induction motors
>
> > Dr Camacho,
> > I wonder if you have seen the same thing as I have with FEMM.
> > It "appears" that magnetic saturation levels are not observed in
> > the results. For example: silicon core iron as supplied in the
> > installation of FEMM should saturate at about 2 Tesla, but will
> > happily show 3 or 4 tesla or more of magnetic flux flowing
> > through a core. This is obviously not correct. Have you found
> > a way around this or is it just a simulator limitation? Or is is
> > that your simulations do not approach magnetic saturation so that
> > you don't see the problem. My workaround is to increase cross
> > section so that the flux density goes below the "known" saturation
> > level.
> >
> > Thanks,
> > Dave Squires
> >
> Dear Dave,
> Actually, I have a Doctoral student that is doing that work. We are
> starting with the saturation right this moment. The thing is, we
> made a double face linear induction motor, based on an ordinary
> induction motor. So, we have the machine working at our lab but
> we had no idea about saturation aspects. The question was: Are
> we making an optimized linear induction motor? Probably not, so
> we decided to use your program to see the saturation level. The
> machine is working with no load at all, the load is only a flat
> aluminum disk around 1 cm thick. Propelling the disk the motor
> current was very small and as your program has proved there was
> no saturation. We are now increasing the motor current, and we
> decided to use the Iron-Si 4% magnetization curve. Which is the
> closest material to our Iron-Si armature. I do not have an answer
> about the FEMM performance yet, but as soon as I got them, you
> be sure that I will exchange my experiences with the FEMM
> comunity.
> Concerning Gabrielle's idea, I think it is worth to have a good look
> on it, and this could be a simulation limitation, but this can only be
> answered with a thorough look at the source code.
>
> Many thanks for you attention to my query. I certainly will have
> many questions to ask you about your program.
>
> With my sincere regards,
>
> Dr. J.R. Camacho - IEEE Member: 01981539
> UFU - School of Electrical Engineering - P.O. Box: 593
> Phone:+55.34.239.4166/250 - Fax: +55.34.236.9530
> 38400.902 - Uberlandia - MG - Brazil
>
>