A non-linear electromagnet

Problem statement

Consider an electromagnet whose core is non-linear and contains a gap of air.

Extracted from the Part 1A Electromagnetics Handout 3 - Magnetic Materials.

Objective : to find the magnetic field strength B.
Principles : Ampere's Law and flux conservation.

Method of analysis :	1)	Application of Ampere's Law and flux conservation. 
			2)	Interpolate from a magnetisation curve.

Sketch :

Maths :

Matlab(R) solution
Solution variables
Input variables



Mean length of core, lm (metres)		
Length of air gap, lg (metres)			
Number of turns on coil, n (metres)		
Current through coil, I (Amperes)		
Field intensity Hm for the magnetic material	



For B=a - b*(H for the magnetic material)

Output variables



Coefficients a, b