Turbomolecular pump

A turbomolecular pump comprising:

• a plurality of rotor blades;
• a position sensor for detecting a position of the rotor blades;
• at least one pair of controlling electromagnets for levitating the rotor blades and for controlling at least one of a radial position and an axial position of the rotor blades;
• a compensating circuit for compensating the radial position or the axial position of the rotor blades in accordance with the position of the rotor blades detected by the position sensor;
• current supplying means for supplying electric current to the controlling electromagnets through the compensating circuit;
• controlling current detecting means for detecting a current flowing through the controlling electromagnets;
• current anomaly judging means for judging whether or not the current detected by the controlling current detecting means exceeds a preselected current value;
• time anomaly judging means for judging, when the current anomaly judging means judges that the current detected by the controlling current detecting means exceeds the preselected current value, whether or not the current exceed lasts more than a preselected amount of time;
• and
• stopping means for stopping the current supply from the current supplying means to the controlling electromagnets when the time anomaly judging means judges that the lapse of time from the start of the current exceed is greater than the preselected amount of time.