Analysis of attractive force of pull-type single phase AC electromagnets

The static pull force characteristics of an AC electromagnet are analyzed with a method which combines the equation of the motion of the armature and analysis of the magnetic field by the finite-element method. Using this method, it is possible to find out whether the AC electromagnet can pull up the armature or not. It is shown that a single-phase AC electromagnet can pull at least the same weight as the average magnetic force. The static pull force characteristics are affected by the restitution coefficient between armature core and stand. The validity of the proposed method for the design of optimal single-phase AC electromagnets is confirmed by experiment