NEW CHALLENGE - ELECTROMAGNETIC DESIGN OF BLDC MOTORS FOR HIGH-SPEED FLUID FILM BEARING SPINDLES USED IN HARD-DISK DRIVES

It is a new challenge in the electromagnetic design of spindle motor w hen a hard disk drive is upgraded to a high speed one with either ball bearing or fluid film bearing. In this paper, detail discussion and a nalysis are made on the problems associated with converting low speed Brushless DC motor to high speed one used in fluid film bearing spindl es. A design example is given for better understanding these problems. For a fixed form factor hard disk drive, the capacity of hard disk dr ive might be reduced unless high density medial and recording techniqu e are used.