The
positioner Is a moving coil type
of
linear motor wherein the signal applied
to
the coil
results in a magnetic field which reacts with the magnetic field of the permanent magnet.
The
force thus produced is used for purposes of controlling the position of the carriage.
Speed
of
the positioner carriage movement is controlled
by
sensing its instantaneous
velocity utilizing the magnetic velocity transducer.
The
magnetic velocity transducer consists
of
a moving magnet within a fixed coil.
The
position of the positioner carriage is sensed
by
using the optical detent type
of
position
transducer.
NOTE
There
is no actual mechanical detenting
of
the positioner
carriage.
The
positioning
at
a given cylinder is achieved
entirely
by
electronic techniques.
Dc
power to various electronic circuits is provided by the power supply which takes the
line
voltage input, transforms it to a suitable voltage level, then rectifies and filters the
output of the transformer. The output is then provided to the power regulators located on
the
Servo PCBA.
Also
contained
on
the power supply assembly
are
the motor start capacitors for the ac
induction drive motor and a
small Motor Control PCBA.
The
Motor Control
PCBA
contains
ground isolation
and
power control circuitry for operating the drive motor. This PCBA Is
separate from other PCBAs in order to isolate the line voltage.
1.5
MECHANICAL
AND
ELECTRICAL
SPECIFICATIONS
The mechanical
and
electgrical specifications summary for the disk drive is shown in
Table
1-1.
1.5.1
INTERFACE SPECIFICATIONS
Levels:
True
= Low =
+0.2
*O.2v
False
:;:
High = + 3.0
.:~:~:
The
interface circuits
are
designed so that any disconnected wire results in a false signal.
Figure 1-7 shows the configuration for which the drivers
and
receivers
have
been
deSigned.
1-7
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