Drop-out voltage cannot be adjusted and depends
high voltage generated by a megger can easily damage
on the tolerance of resistors in the Schmitt-trigger
electronic components. If a proximity switch doesn't
circuit. If drop-out voltage is not within tolerance,
pick up or drop out properly, make the following checks
check the values of resistors R19 through R23.
on the amplifier at the panel:
If the above checks and adjustments do not correct
1. Check the indicating lamp for operation
the trouble, the problem must be internal to the
2. Measure voltage and frequency input and output
amplifier. In this case, the amplifier should be removed
at the T1 transformer (take all measurements
from the panel for servicing.
with high impedance meters greater than 1
megohm).
SUMMARY
3. Measure drop-out voltages between terminals
Elevators have become one of the mainstays of
equipment aboard ship. While they present a great
#3 and #5 of the proximity switch (with and
without the cam target at the pick-up point). See
convenience when moving stores and equipment, they
the manufacturer's manual for proper tolerance
are also one of the most hazardous pieces of gear to
values.
operate. When dealing with the elevators aboard ship,
IF any of the above measurements are out of
you should be sure safety is always the number one
priority. Sailors and shipyard workers are killed almost
tolerance, you should first check for metal, other than
every year due to improper work and maintenance
the metal target in the sensing field
practices. Refer to the applicable technical manuals and
training material aboard ship for safety precautions to
The null point of the sensing head may need
adjusting. To adjust the null point, remove the soft plug
be observed when operating or maintaining the
in the tuning slug hole of the sensing head and turning
elevators aboard your ship.
the slug with an Allen wrench. Remove the wrench
when checking the null point.
UNDERWAY REPLENISHMENT
The amplifier sensitivity is adjusted by removing
SYSTEM
the plug button on the top right of the amplifier and
The underway replenishment (UNREP) system is a
adjusting the potentiometer (Pi) screw. Be careful when
high-speed, heavy weather, day or night method of
inserting the screwdriver. Clockwise rotation reduces
transferring missiles and other loads between a
pick-up voltage, while counterclockwise rotation will
noncombatant supply ship and a combatant ship while
increase the pick-up voltage. This adjustment is very
underway. The system shown in figure 5-29 is made up
sensitive and must be executed cautiously.
Figure 5-29.--UNREP system.
5-47
