# Electro-Magnetics with FEMM

Finite Element Method Magnetics (FEMM) is an Open source software for Electro-Magnetics. It can be driven by Scilab, as described in the following examples:

## Coil

This program consider an axisymmetric magnetostatic problem of a cylindrical coil with an axial length of 100 mm, an inner radius of 50 mm, and an outer radius of 100 mm. The coil has 200 turns and the coil current is 20 Amps. There is an iron bar 80 mm long with a radius of 10 mm centered co- axially with the coil. The objective of the analysis is to determine the flux density at the center of the iron bar, and to plot the field along the r=0 axis. This analysis defines a nonlinear B-H curve for the iron and employs an asymptotic boundary condition to approximate an "open“ boundary condition on the edge of the solution domain.

## AC conduction

This example is inspired by this video: https://www.youtube.com/watch?v=U8GrV9UKVRw

It implements the AC Conduction p216: http://www.caesoft.es/productos/quickfield/Descargas/Manual%20del%20usuario%20v5_9.pdf

## Magnet dynamics

This geometry comes from Chap. IX, Figure 7 of Herbert Roters classic book, Electromagnetic Devices.

The program moves the plunger of the magnet over a stroke of 1.5in at 1/10in increments solving for the field and evaluating the force on the plunger at each position.

When all positions have been evaluated, the program plots a curve of the finite element force predictions.