TM5-6115-593-34
NAVFAC P-8-631-34
TO-35C2-3-463-2
(1)
Remove and tag wires to terminals 1
through 6 on the terminal board.
(2)
Remove four screws (1 and 3, figure
4-10) from each unit.
(3)
Replace
motor-operated
potentio-
meter P4 or P5 on shelf by attaching
four screws (1 and 3, figure 4-10).
(4)
Connect wires to terminals 1 through
6 on terminal board. Remove tags.
b.
Test. The following testing procedure
applies to both motor operated potentio-
meters P4 and P5, unless otherwise
indicated.
(1)
Test
chassis
isolation
with
an
ohmmeter (set on high scale) by
measuring
between
chassis
and
terminals 1 through 6 on the terminal
board. Meter reading should be no
continuity.
(2)
Referring to figure 4-16, provide a test
setup as follows:
(a)
Connect the (-) of a 24V DC
source to terminal 6. The (+)
side of the center terminal of
SPST switch as shown.
(b)
Label
switch
RAISE
and
LOWER. Connect the RAISE
terminal of SPDT switch to
terminal 5 and the LOWER
terminal of SPDT switch to
terminal 4.
(c)
Connect an ohmmeter between
terminals 2 and 3.
(d)
Turn 24V DC power on. Set
SPDT switch to RAISE. Meter
shall
read
230
±5
ohms
connected between terminals 2
and 3.
(e)
Set SPDT switch to LOWER.
Meter shall read 8 ±5 ohms
connected between terminals 2
and 3.
NOTE
If ohmmeter readings at steps (d) and
(e)
are
incorrect,
cams
need
adjustment.
(f)
The 230 ±5 ohm reading in step
(d) is adjusted with cam B. This
cam should be adjusted to stop
the motor at 230 ±5 ohms, see
figure 4-17.
(g)
The 8 ±5 ohm reading in step
(e) is adjusted with cam A. This
cam should be adjusted to stop
the motor at 8 ±5 ohms, see
figure 4-17.
NOTE
Potentiometer reading adjustments in
steps (f) and (g) are for motor-operated
potentiometer P5. For P4, readings
are 500 ±5 ohms in step (f), and 1 ±5
ohms in step (g).
(h)
Verify that the motor can be run
at 1 rpm to 3 rpm as R3 is
rotated
from
clockwise
to
counterclockwise. Leave R3 set
for 3 rpm operation.
c.
Repair. Components within the motor-
operated
potentiometers
that
may
be
repaired are: brush replacement in motor
M1, tightening of set screws on gears, cam
adjustments and clutch torque.
(1)
When motor M1 (9, figure 4-15)
brushes are worn under 0.25 inch (6.4
mm) long, they must be replaced.
(2)
Remove cover (3) by moving three
screws (1) and washers (2). Tighten
setscrews (19) on gear assembly (20)
and setscrews (28) on gear (29).
(3)
Adjust cams A and B in accordance
with procedure in paragraph 4-26b (f)
and (g).
(a)
With
cover
(3)
removed,
remove motor mounting plate
(17) and motor (9) by removing
two screws (8).
4-26