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# Re: [FEMM] Approximate Solution of Transient and periodic analysis withFEMM

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- Subject: Re: [FEMM] Approximate Solution of Transient and periodic analysis withFEMM
- From: "Fabio" <fmilanesi@tin.it>
- Date: Sat, 28 Feb 2004 18:43:30 +0100
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I made study of transient to evaluate inrush current in a single phase transformer using Femm. First i made a magnetic model of transformer and i used Femm to evaluate the incremental inductance of the primary winding Li= dFlux / dI I used a Lua script to obtain Li as function of primary current I starting from low current and go on until very hight saturation of core. The L(i) was evaluted in 25 points and i used linear interpolation between evaluated points. Then i write the differential equation v(t) = L(i)*di/dt +R*i(t) and solved this equation using Octave ( www.octave.org ) . The result was validated with measure on a real transformer and the error was very small. I made also a non-linear model of this transformer for Spice so i can evaluate the inrush current and the armonics in no load current using transformer in more complex circuits. I write a paper about this work and it will be published the next month on italian magazine "Elettrificazione" If you are italian as me i can post you the article, i'm not able to translate it in decent english ... Best regards Fabio ----- Original Message ----- From: ac To: femm@list.foster-miller.net Sent: Saturday, February 28, 2004 1:03 PM Subject: [FEMM] Approximate Solution of Transient and periodic analysis withFEMM I wonder if it is possible, by using some tricks or LUA script techniques, to evaluate two general problems that very often may appear in the common magnetic circuit design. The two problems are: the transient ( as slope , step..) and the periodic but non sinusoidal (as trapezoidal, rectangular shape..) current sources analysis in case of coils in free space or coil + non linear iron circuit. I would appreciate any suggestion, help or comments. Thanks a lot in advance, Arnoldo Yahoo! Mail: 6MB di spazio gratuito, 30MB per i tuoi allegati, l'antivirus, il filtro Anti-spam _______________________________________________ FEMM mailing list FEMM@list.foster-miller.net http://femm.foster-miller.net/mailman/listinfo/femm

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  - [FEMM] Approximate Solution of Transient and periodic analysis with FEMM
    - From: ac <ac090960@yahoo.it>

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