MAGNETIC DISK DEVICE AND ITS HEAD ADHESION MEASURING METHOD

摘要

PROBLEM TO BE SOLVED: To reduce a measuring error and detect rotation of a magnetic disk by measuring adhesion between the magnetic disc and a magnetic head by driving a spindle motor. SOLUTION: A detection output signal Vz is measured by selecting U-V phase coils by a coil selecting circuit 6 by operating a signal Select. The detection output signal Vz is measured by selecting V-W phase coils by the coil selecting circuit 6. The detection output signal Vz is measured by selecting W-U phase coils by the coil selecting circuit 6. The coil showing the maximum detection output signal is selected by the coil selecting circuit 6. Next, a sawtooth wave voltage generation circuit 1 is started by a signal Start and a sawtooth wave current is made to flow through the coil, and a current measurement signal Vi obtained by amplifying a voltage drop across a resister 3 and the voltage of the detection output signal Vz are measured continuously and simultaneously. A variable ratio of Vz and adhesion can be obtained within a short time and without damaging the device.