Fujitsu MAH3091MC - Enterprise 9.1 GB Hard Drive, Maintenance Manual

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8 - 2 C141-E103-01EN
8.2.1 Disks
The disk configuration of each DE is shown as follows:
•
The DE for the MA3182 series contains 2 disks whose external diameter is 95 mm and
internal diameter is 25 mm.
•
The DE for the MAH3091 series contains 1 disks whose external diameter is 95 mm and
internal diameter is 25 mm.
•
The DE for the MAJ3364 series contains 5 disks whose external diameter is 84 mm and
internal diameter is 25 mm.
•
The DE for the MAJ3182 series contains 3 disks whose external diameter is 84 mm and
internal diameter is 25 mm.
•
The DE for the MAJ3091 series contains 2 disks whose external diameter is 84 mm and
internal diameter is 25 mm.
Each time disk rotation stops, the read-write heads touch the disk surfaces. Disk surfaces
withstand at least 15,000 head touch operations at disk rotation start and stop.
8.2.2 Heads
The read/write head configuration is shown in Figure 1.5.
There are 10 read/write heads for the MAJ3364 series, 5 for the MAJ3182 series, 3 for the MAJ3091
series, 4 for the MAH3182 series and 2 for the MAH3091 series. These heads float up from the surface
of the disk automatically when the spindle motor’s speed has reached a certain speed.
8.2.3 Spindle mechanism
The spindle mechanism consists of a disk stack assembly and a spindle motor. The disk stack
assembly is directly driven by the direct drive type DC spindle motor. The rotational frequency of
this spindle motor is 7,200 min
-1
(7,200rpm) or 10,025 min
-1
(10,025rpm). A counter-electromotive
force is generated by the drive current in the spindle motor coil. A fixed rotational frequency of
the spindle is maintained by comparing the frequency of the counter-electromotive voltage with the
reference frequency generated by the crystal oscillator.
8.2.4 Actuator
The actuator consists of a voice coil motor (VCM) and a head carriage. The voice coil motor
moves the head carriage to the inner or outer side of the disk. The head carriage position is
controlled by feeding back servo information read by the heads.
8.2.5 Air filters
There are two filters in the disk drive, the breathing filter and the circulation filter. The breathing
filter is used to conduct filtered air into and out of the DE. Starting or stopping the disk generates
heat in the spindle motor in the DE, causing temperature variation in the DE. This temperature
variation expands or compresses the air in the DE causing the filtered air to come in or go out of
the DE. At times when the atmospheric air pressure changes, such as when the disk drive is
shipped by airmail, filtered air enters the DE.