Table of Contents
Advertisement
.
..
·
adjustment can be made by loosening the
two
mounting screws (Figure 20) on the outside face of
the stripper plate and moving the block assembly up or down
.
The tape pressure guide should
be
adjusted so that there is .015" -
.020"
clearance between the stripper plate and guide.
MOUNTING
SGREWS
STRIPPER
PLATE
Figure 20
.
End-of-Tape Switch
Adjustment:
7
.2 Capstan Shaft
Commutator
7.2.1
Description
(a) switch sensing end of
tape;
{b) switch sensing tape
The
commutator unit is
designed
to
provide
a
"
free-running" operational
mode
,
and thus
permit tape reading without using a tape
reading
pulse generator
.
The normal "tape-
stepping" mode of the standard reader is retained as an optional operating mode. To obtain
"free-running", an integral commutator generates a switch closure signal that has an adjustable
duration
which
is
discreetly related
to the capstan velocity, and whose phase is adjustable and
related to the tape hole and star
wheel
reading position. Switch
closure
and phase angle is ad-
justed
to
fulfill specific customers
requirements
.
7
.2.2 Mechanical Operation (See Figure 21)
A
commutator is directly driven by the read head capstan shaft and is mounted
just to the
rear
of the capstan bearing support plate.
Two
adjustable brushes are located on
either side of
the
commutator
and
are supported by the capstan bearing plate
.
The commutator
is composed of 20 angular segments, each 5 degrees wide. Segments are equally spaced, center
to center,
every 18
degrees of
arc. The
commutator segments are printed
circuit.
s retained on
an
aluminum
hub.
The
commutator is locked in position on the capstan shaft with a set
screw.
The
two sets of brushes are made of multiple wires retained in a nylon brush
holder
.
The
brush holders,
held
in
position
with a screw, may·be moved for adjustment of both
duration and
phase
angle of the commutator switch closure.
S£ATT
L
£
Page
18
Advertisement
Table of Contents
