An experimental study of high-speed rotor supported by air bearings: test rig and first experimental results

The paper contains the description of the test rig and first experimental data regarding the mechanical and the thermal behaviour of a 7 kg rotor, 460 mm long and with a diameter of 50 mm, supported by externally-pressurized air-lubricated bearings. The rig allows to load the rotor radially and axially both in static and dynamic conditions and to measure the orbits on the supports. The rotating imbalance response at different speeds has been measured up to 60,000 rpm. The orbits are always synchronous with the rotational speed and their shape changes also with temperature (though this effect is almost negligible). The rotor is stable and does not present whirl instability.