Dc Direct Drive Spindle Motor; Carriage Read/Write Assembly Heads; Stepping Motor; Head Load Cam Assembly - NEC FD1165 Maintenance Manual

1.2.3 Dc Direct Dtive Spindle Motor
The dc direct drive motor (not shown) rotates the spindle
assembly. This dc motor eliminates the problems that are
associated with conventional ac motor drives.
• The motor does not use drive pulleys or belts, elim-
inating the problems associated with these parts.
• The motor consumes less power than conventional ac
motor s. Low-power, inexpensi ve power suppli es can
be used.
• The motor uses direct current, so that there are no
concerns about voltages and frequencies.
• The motor generates less heat than conventional
un its.
The spindle motor has an up-to-speed time of 700 ms.
1.2.4 Carr! age Read/Wr i te Assembly Heads
The read/write heads touch each side of the flexible disk,
allowing data to be written to the flexible disk and to be
read from it. The read/write heads are part of a precision
carriage assembly that shifts the heads from track to track.
During the loading of a flexible disk, the read/write heads
are held away from the surface of the flexible disk.
1.2.5 Stepping Motor
The stepping motor, under microprocessor control, positions
the carriage assembly with a tensioned steel belt. This
arrangement provides fast and accura te data access. For
each pulse the stepping motor receives, the stepping motor
shaft rotates 1.8 degrees. This action, in turn, moves the
carriage 1/2 track on the flexible disk.
1.2.6 Head Load Cam Assembly
The head load cam assembly (rotary solenoid) lowers the
heads onto the flexible disk with a force that is controlled
by a microprocessor. This action prevents damage to the
flexible disk and reduces wear of the read/write heads.
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