| 摘要 |
PURPOSE:To continuously, with high accuracy and easily measure a coefficient of friction between a medium and a head while an endurance test is being performed, by monitoring the lowest voltage by which a spindle motor can be started. CONSTITUTION:As for a hard disk drive, a head and a medium execute a contact start-and-stop (CSS). Therefore, a coefficient of friction between the head and the medium is derived by measuring a current value at the time when a spindle motor is started. When the spindle motor is not moving, a proportional relation is formed exactly between a voltage and a current applied to the motor. Therefore, driving voltage of the motor is boosted continuously or stepwise, a load torque to the motor is calculated by monitoring the lowest voltage by which the spindle motor can be started, and also, the coefficient of friction between the head and the medium is calculated therefrom. In such a way, the coefficient of friction between the head and the medium can be measured on the way of a CSS endurance test. |
