Electromechanical actuator for a fire protection installation, the electromechanical actuator comprising at least: - a casing, - an electric motor, - an electromagnetic device, and - an output shaft, the electromagnetic device comprising at least: - an electromagnet, the electromagnet comprising at least a body and a coil, - a yoke, the body of the electromagnet being arranged facing the yoke, in an assembled configuration of the electromagnetic device, - a first jaw, and - a plate, the plate being configured to move relative to the first jaw, in the direction of an axis of rotation, in the assembled configuration of the electromagnetic device, the electromagnetic device having a first state, in which the electromagnetic device blocks the rotation of the output shaft of the electromechanical actuator relative to the casing, and a second state, in which the output shaft of the electromechanical actuator is free to rotate relative to the casing, characterised in that the electromagnetic device also comprises at least: - a second jaw, the plate being arranged between the first and second jaws (33, 35), in the assembled configuration of the electromagnetic device, the second jaw being configured to move relative to the first jaw, in the direction of the axis of rotation, in the assembled configuration of the electromagnetic device, - a first friction lining and a second friction lining, the first friction lining being arranged between the first jaw and the plate, in the assembled configuration of the electromagnetic device, the second friction lining being arranged between the second jaw and the plate, in the assembled configuration of the electromagnetic device, the first friction lining being fitted against a first face of the plate, the second friction lining being fitted against a second face of the plate, the second face of the plate being opposite the first face of the plate, in that the yoke is configured to move relative to the body of the electromagnet, in the direction of the axis of rotation, in the assembled configuration of the electromagnetic device, and in that, in the assembled configuration of the electromagnetic device, an air gap is formed between the body of the electromagnet and an end wall of the yoke, at least when the electromagnetic device is in its second state. - a casing, - an electric motor, - an electromagnetic device, and - an output shaft, - an electromagnet, the electromagnet comprising at least a body and a coil, - a yoke, the body of the electromagnet being arranged facing the yoke, in an assembled configuration of the electromagnetic device, - a first jaw, and - a plate, the plate being configured to move relative to the first jaw, in the direction of an axis of rotation, in the assembled configuration of the electromagnetic device, - a second jaw, the plate being arranged between the first and second jaws (33, 35), in the assembled configuration of the electromagnetic device, the second jaw being configured to move relative to the first jaw, in the direction of the axis of rotation, in the assembled configuration of the electromagnetic device, - a first friction lining and a second friction lining, the first friction lining being arranged between the first jaw and the plate, in the assembled configuration of the electromagnetic device, the second friction lining being arranged between the second jaw and the plate, in the assembled configuration of the electromagnetic device, the first friction lining being fitted against a first face of the plate, the second friction lining being fitted against a second face of the plate, the second face of the plate being opposite the first face of the plate,