Abstract: A control process for a control system of a load system connected to an electric grid through the control system wherein the control process is configured to provide one or more adapted drive commands to the control system dependent on the grid frequency. The control system may include an inverter, a converter, a thyristor bridge or contactors and the load may be a motor. A control device for implementing the control process also is disclosed.

Abstract: A ventilation opening for an aeration system, in particular of the air admission opening type, of the type comprising a body delimiting an air conveying duct and a flap pivotally mounted on the front facade of the body between a closed position and an open position, and further comprising a system for blocking the flap in the open position and in the closed position, comprising an elastically deformable locking blade that is fastened to the flap and provided with at least two stops and a stopping device incorporated to the front facade of the body and presenting at least two bearing elements, where the locking blade cooperates with a stopping device so that the flap passes from a closed position, wherein a stop of the locking blade bears against a bearing element, to an open position, wherein another stop of the locking blade bears against another bearing element, by initially pushing the flap against the front facade and then by spacing apart the cover from the front facade, and the flap passes from the open