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 (X), 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 , 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 (X), 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 (X), in the assembled configuration of the electromagnetic device , and in that , in the assembled configuration of the electromagnetic device , an air gap (E) 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 (X), in the assembled configuration of the electromagnetic device , - a second jaw , the plate being arranged between the first and second jaws , 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 (X), 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 , <EOS>