A plurality of permanent magnets are arranged in a pair of yoke sections such that mutually adjacent and facing magnetic poles have opposite polarities. An armature winding (6) is arranged in a magnet gap and an electrical current is fed through said armature winding (6) in order to ensure relative movement with respect to the permanent magnets. A linear scale (8) is arranged on the stator such that it is located on the line of the longitudinal force centre or in its vicinity, and a read head (7) is arranged on the moving part such that it faces the linear scale. <IMAGE>
