Abstract: A vacuum pump a the magnetic bearing assembly includes the magnetic bearing assembly with rotor position sensors and backup bearings being placed inside the rotatable shaft of the vacuum pump. The sensor placements are independent of the bearing position, so that the respective radial sensors can be at the same axial position as the respective radial bearings, which provides sensors co-location and a space saving within a turbopump housing, in particular, in its axial direction, while sensors and mechanical backup bearings are placed in a better protected area with respect to pumped corrosive gases.

Abstract: A vacuum pump is provided with back-up bearings in addition to magnetic bearings for supporting its rotor with respect to the pump housing. The rotor has a hollow rotary shaft extending backwards enclosing in its inner space a forwardly protruding tubular shaft affixed to the pump housing, and another cylindrical member affixed to the rotor protrudes backward inside this fixed tubular shaft. One set of back-up bearings is provided on the outer surface of the fixed tubular shaft spaced from the inner surface of the rotor shaft and another set of back-up bearings is provided on the inner surface of the fixed tubular shaft, spaced from the protruding cylindrical member. The back-up bearings thus positioned can be made smaller for improved dynamic emergency capabilities.