in the bottom line of the time diagram of fig5 is shown how the angle alpha of the lever arm 3 changes in accordance with the progress of the cycle in the vicinity of segment a the lever arm 3 driven by cam plate 9 rod 6 and arm 2 presses the several anchors 19 against the appropriate magnet core 21 the return movement of lever arm 3 follows in the area of segment b as is shown in the example the contact phase path segment a runs for forty degrees of the turn of machine main shaft 11 the cycle signal s3 generated by proximity sensor 41 has the form of an impulse which in this example has the same forty degree duration and whose initial time point to is displaced with respect to the beginning of phase a so that the end point t1 is formed in the area of the declining phase segment b the activation signal s1 has the same phase as the cycle signal s3 when the program device 38 determines that the pattern requires the repulsion of the anchor 19 in the other case the activation signal s1 is zero as is shown in phantom in the second line of fig5 the displacement of the initial time point to has the advantage that the anchors 19 are already biased towards the magnet core 21 contact them before repulsion current can be applied.