Method and apparatus for measuring half frequency whirl in a spindle motor

摘要

An apparatus and method of indirectly measuring half frequency whirl in a spindle motor having a rotor adapted to rotate a disc having a track which is followed by a transducer head that is actuated by a control system is provided. Vibration signals produced at the transducer head while the transducer head follows the track are detected. The half frequency whirl is determined as a function of the detected vibration signals.