Fujitsu MPA3017AT, Product Manual

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C141-E034-02EN 4 - 3
4.2.3 Spindle
The spindle consists of a disk stack assembly and spindle motor. The disk stack assembly is
activated by the direct drive sensor-less DC spindle motor, which has a speed of 5,400 rpm ±0.5%.
The spindle is controlled with detecting a PHASE signal generated by counter electromotive
voltage of the spindle motor at starting. After that, the rotational speed is kept with detecting a
servo information.
4.2.4 Actuator
The actuator consists of a voice coil motor (VCM) and a head carriage. The VCM moves the head
carriage along the inner or outer edge of the disk. The head carriage position is controlled by
feeding back the difference of the target position that is detected and reproduced from the servo
information read by the read/write head.
4.2.5 Air filter
There are two types of air filters: a breather filter and a circulation filter.
The breather filter makes an air in and out of the DE to prevent unnecessary pressure around the
spindle when the disk starts or stops rotating. When disk drives are transported under conditions
where the air pressure changes a lot, filtered air is circulated in the DE.
The circulation filter cleans out dust and dirt from inside the DE. The disk drive cycles air
continuously through the circulation filter through an enclosed loop air cycle system operated by a
blower on the rotating disk.