An Analytical Solution for the Normal Force in Linear Actuators

Some electromagnetic planar and linear motors rely on a mover with permanent magnets and a stator with armature windings mounted around a ferromagnetic armature core. In such devices, the mover can develop movement through a straight line by means of a propulsion force. Furthermore, a normal force is also present. It acts as an attraction force between the permanent magnets and armature ferromagnetic cores. As a result, it loads bearings and shafts that must support the mover and can affect the mobility of the latter. The present work proposes and validates an analytical model for that normal force. Theoretical and experimental results show a good agreement