TM 9-4940-549-14&P
MAINTENANCE OF AIR COMPRESSOR AND RELATED PARTS
GENERAL. The two-stage air compressor is driven by a 2-horse-power
motor. The items comprise a self-contained unit delivering an adequate
volume of air to the air receiver tank to maintain an air pressure dif-
ferential of 125 to 150 psi. The air receiver tank is an integral part of
the shop set roof. The air receiver tank pressure gage indicates the
pressure in the tank. A pop-off valve set at 175 psi prevents the sy-
stem from becoming overloaded. A draincock beneath the tank provides
a means of draining the condensation out of the system before usage.
This should be done daily, before the compressor is put into use.
AIR COMPRESSOR.
Removal (Refer to figu re 14-1).
a.
(1) Disconnect and tag electrical leads at motor.
(2) Disconnect air line to receiver.
(3) Remove four bolts and four lockwashers securing air compressor
base to cabinet.
Installation.
Install the air compressor and drive motor in reverse
b.
order of removal.
14.3.
AIR COMPRESSOR DRIVE MOTOR ASSEMBLY.
Removal. Tag and disconnect electrical lead (fig. 14-1). Remove
a.
four bolts and nuts and remove drive motor assembly.
Install the drive motor assembly in reverse order of
b.
Installation.
deflection between pulleys.
AIR COMPRESSOR PRESSURE SWITCH.
a.
Adjustment.
To raise CUT-IN and CUT-OUT pressure, turn pressure adjus-
(1)
ting screw clockwise.
To lower DIFFERENTIAL (namely the difference between CUT-IN
(2)
and CUT-OUT pressure), turn differential screw at edge counter-
When adjusting this screw, do not turn it further
clockwise.
than it will turn easily.
(3)
To increase DIFFERENTIAL and maintain same CUT-OUT pressure,
turn differential screw at edge clockwise and at the same time
turn center screw counterclockwise.
