Abstract: Control of the start-up and operation of a single phase synchronous motor with a permanent-magnet rotor (9) is proposed, wherein the single-phase synchronous motor (1) comprises at least one stator winding (5, 6) which is connected in series with an AC voltage sources, in which there are a sensor (10) for measuring the rotor magnetic field and an arrangement for phase-gating (11, 13), which connect the AC voltage source to the stator winding as a function of the magnetic-field sensor signal, in such a manner that the current which flows in consequence in the stator winding produces a rotor torque in the rotation direction without any critical states occurring with respect to demagnetization of the rotor. To this end, after the end of a delay time for phase-gating control, the stator current is not triggered until predefined conditions are satisfied. Momentary overloading of the motor and stalling are reliably prevented. A signal which reflects the load level on the motor is produced for external use.

Abstract: A piece of wood is prepared for impregnation by causing it in steps to be perforated by a plurality of needles which are moved back and forth with the workpiece, and either rotate individually or are subject to additional oscillatory or impact-producing axial movement.