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Re: [FEMM] Solenoid charge

Many thanks for reply; the explanation was very exhaustive indeed!
One questions more, I wonder if, using non linear materials, there are some tricks to evaluate (approximate solution, linearization ...) to solve the time varying non linear problems and which are the parameters ( eddy currents, losses...) we can get with a certain reliability.

Any suggestion would be very appreciated, Thanks again for any contribution Bye Wang


yanze wuan wrote:

Dear all,
my problem is to simulate a solenoid charge by using both linear ramp
of current and saw periodic shaped current profile. The calculaton should take into account the losses in coil and skin effect.
Can somebody suggest any way to evaluate filed, current density distribution and losses by using femm and or lua ?

Thanks Wuan 

As long as the materials are linear, you can break a periodic problem up
into a series of problems at different frequencies and superimpose the
results.  For example, if you have a saw wave that goes from 0  to 1
with a period of T, the  waveform could be represented by a DC problem
with an amplitude of 1/2, plus the sum  of AC problems with a current
of: -(Sin[(2*n*Pi*t)/T]/(n*Pi)) for n from 1 to infinity.  In terms of
FEMM's time harmonic representation, that would be a currents of
amplitude of j*(1/(n*Pi)) at a frequencies of (n/T) Hz.


--
David Meeker
dmeeker@xxxxxxxx
http://femm.berlios.de/dmeeker

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