A rotating electrical machine for a motor vehicle comprising a rotor (2) supplied with an excitation current (ie), a stator (3) comprising a polyphase winding and coupled to the rotor (2), a thermal protection module (4) suitable for evaluating at least one temperature (T1, T2, T3) in the machine and for comparing the temperature with an associated thermal protection threshold (Th), a control device (5) supplying the excitation current (ie) depending on an operation mode command (RQ) and the temperature comparison, so as to operate the rotating electrical machine (1) according to a mode of operation chosen from a nominal generator mode in which the machine is configured to deliver a first maximum power or at least one extended generator mode in which the machine is configured to deliver a second maximum power greater than said first maximum power.