The following invention is an electromechanical system (1) that is to be connected to an electricity supply (7), comprising: an electric machine (2) that can operate as an independent generator with a rotating shaft, and a switching system (9) allowing i) in the first configuration, the electric machine to operate as a motor in the case where the connected device (4) is normally driven or as a generator in the case where the coupled device is normally driving, and ii) in the second configuration, the electric machine to operate as an independent generator, the electrical energy generated by the electric machine (2; 22) being dissipated in the machine and in a dissipative load (13).