| US 7,605,996 B2 | ||
| Method and system for detecting a change in a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk | ||
| Peter Michael Baumgart, San Jose, Calif. (US); Charles Raymond Davis, San Jose, Calif. (US); Gary Allan Herbst, San Jose, Calif. (US); Bernhard E. Knigge, San Jose, Calif. (US); Charles Mathew Mate, San Jose, Calif. (US); and Bruce Alexander Wilson, San Jose, Calif. (US) | ||
| Assigned to Hitachi Global Storage Technologies Netherlands B.V., Amsterdam (Netherlands) | ||
| Filed on Dec. 28, 2007, as Appl. No. 11/965,980. | ||
| Prior Publication US 2009/0168221 A1, Jul. 02, 2009 | ||
| Int. Cl. G11B 21/02 (2006.01); G11B 15/46 (2006.01) | ||
| U.S. Cl. 360—75 [360/73.03] | 21 Claims |
| 1. A method, comprising:
detecting a change in a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk, the change being
caused by head-disk contact,
wherein detecting the change in the rotational velocity includes measuring a change in a current applied to a motor driving
the spindle to maintain about a constant rotational velocity thereof,
wherein detecting the change in the rotational velocity includes measuring a change in frequency of an alternating current
applied to a motor driving the spindle to maintain about a constant rotational velocity thereof.
|