Abstract: In a rotary assembly comprising a rotor mounted in rotation in a stator about a mean axis of rotation, a radial position sensor comprises three induction sensors distributed in the stator substantially at 120° from one another around the rotor and equidistant from the mans axis of ration. The induction sensors are cabled in star connection with a common connection point, and are powered by a balanced three-phase sinusoidal voltage source with a neutral point. The output voltage, present between the common connection point and the neutral point of the balanced three-phase sinusoidal voltage source, is processed by signal processing means which determine its amplitude and its phase relative to the voltage delivered by the balanced three-phase sinusoidal voltage source. Thus, from only three sensors, two signals are obtained constituting the amplitude image and the angular position of the radial displacement of the rotor gravity axis in the stator.

Abstract: In a rotary assembly comprising a rotor mounted in rotation in a stator about a mean axis or rotation, a radial position sensor comprises three induction sensors distributed in the stator substantially at 120° from one another around the rotor and equidistant from the mans axis of ration. The induction sensors are cabled in star connection with a common connection point, and are powered by a balanced three-phase sinusoidal voltage source with neutral point. The output voltage, present between the common connection point and the neutral point of the balanced three-phase sinusoidal voltage source, is processed by signal processing means which determine its amplitude and its phase relative to the voltage delivered by the balanced three-phase sinusoidal voltage source. Thus, from only three sensors, two signals are obtained constituting the amplitude image and the angular position of the radial displacement of the rotor gravity axis in the stator.

Abstract: A turbomolecular pump comprising a stator and a rotor, said rotor comprising a central shaft and a bell-shaped active portion, said stator comprising an outer portion and an inner portion that penetrates into the cavity of said bell-shaped active portion, and that supports the stator portion of the drive motor, the shaft of said rotor supporting the rotor portion of said drive motor, wherein said central shaft and the bell-shaped active portion of the rotor are made in one piece, without any assembly being necessary, and of a non-magnetic material, said shaft being provided with a central bore which receives the rotor portion of said drive motor, which portion is constituted by a cylindrical permanent magnet.