Granted Patent B2

US 6,870,700 · App. 10/377,897 · Granted Mar 22, 2005

Abstract

Claims (14)

1. A motor control method for a magnetic disk drive comprising a magnetic disk as an information recording medium, a magnetic head for recording/reproducing information to/from the magnetic disk, and a motor for driving the magnetic disk,

the motor having a connection point connecting middle points in a multi-phase Y-connection and capable of realizing a unipolar drive method for successively exciting phases and a bipolar drive method for simultaneously exciting two adjacent phases,

wherein the unipolar drive method is selected when the temperature in the magnetic disk drive is lower than a predetermined temperature and the bipolar drive method is selected when the temperature exceeds the predetermined temperature.

2. A motor control method for the magnetic disk drive according to claim 1 , wherein stationary rotation of the motor is assured by selecting the unipolar drive method or the bipolar drive method.

3. A motor control method for the magnetic disk drive according to claim 2 , wherein the motor uses a fluid dynamic bearing (FDB).

4. A motor control method for the magnetic disk drive according to claim 2 , wherein

temperature detection means is provided inside or outside the magnetic disk drive and

temperature detection by the temperature detection means is performed upon start of the magnetic disk drive to determine whether the temperature is in a predetermined range so that the motor drive method is switched according to the detection result and after the start, temperature detection is performed at a predetermined interval.

5. A motor control method for the magnetic disk drive according to claim 4 , wherein the motor uses a fluid dynamic bearing (FDB).

6. A motor control method for the magnetic disk drive according to claim 1 , wherein

temperature detection means is provided inside or outside the magnetic disk drive and

temperature detection by the temperature detection means is performed upon start of the magnetic disk drive to determine whether the temperature is in a predetermined range so that the motor drive method is switched according to the detection result and after the start, temperature detection is performed at a predetermined interval.

7. A motor control method for the magnetic disk drive according to claim 6 , wherein the motor uses a fluid dynamic bearing (FDB).

8. A motor control method for the magnetic disk drive according to claim 1 , wherein the motor uses a fluid dynamic bearing (FDB).

Assignments (7)