According to electromagnetic laws, the curl of electrical field (E) must be zero, for the circulation is zero, and the curl of magnetic field (H) is not zero, however; its circulation per unit area is the current density by Ampere’s circuital law.Therefor in all magnetic systems, if some magnetic flux lines export from a surface of one volume of space, then same flux lines import to that volume via its other surfaces. It means, for mathematic function of magnetic flux we can write: f(-x) = – f(x) that named odd function. Also because of core symmetrical construction, the flux function can be written by f ( x ) = f ( L