Re: [femm] Linear induction motors

["Jose Roberto Camacho" <jrcamacho@xxxxxx>]

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