Abstract:
The invention relates to an underspeed detection device (2) for a motor (4) comprising a stator and a rotor movable relative to the stator, the detection device (2) comprising detection means (12) able to generate an electric rotation signal (ir) representative of the speed of rotation of the rotor, and electronic analysis means (20) able to analyze the rotation signal (ir) to detect an underspeed situation, characterized in that the detection device (2) further comprises conversion means (18) able to convert part (ip) of the electric rotation signal (ir) into a power supply current (ial) for the analysis means (20), and means for applying the power supply current (ial) to the analysis means (20) for their electric power supply.