“…If some effects are not significant at some times, at other times they contribute significantly. Authors like Smith-Spinweber (1980), Karidis-Turns (1982), MacBain (1985), Kushida (1985), Pawlack-Nehl (1988), Lesquesne (1990a), Yuan-Chen (1990), , Ohdachi et al (1991), Kajima (1992 and, Passarini (1993), Rahman et al (1996), Ando et al (2001), Szente-Vad (2001) and Passarini-Pinotti Jr. (2003) diverge when describing the armature movement of the of the EFI and as to which of the above mentioned phenomena should be considered and which should be neglected. It seems that most of these authors consider it sufficient to calculate precisely the magnetic force attraction, F mag to accurately define the armature movement because basically their mathematical model is described by only three forces, magnetic, elastic (Hook's law) and viscous as shown in Eq.…”