Electromagnetic actuator switching method - includes applying to excitation winding current insufficient to cause armature to move and applying additional signal causing latter to move

摘要

The electromagnetic actuator, is controlled at zero current for a period which guarantees a reliable drop of its armature. A current insufficient to cause the armature to move is then applied to the excitation winding of the actuator. At a desired pull-up instant, an additional signal is applied to the excitation winding. This enables the actuator to be held in a waiting position in which a small additional pulse causes pulling-up of the actuator armature. An accumulator is provided from which the additional signal can be supplied to the excitation winding at predeterminable instants and/or values of operating parameters, such as speed, air flow rate.