Figure 4-11. Air compressor and drive motor assembly, removal and
turn differential screw at edge counterclockwise.
Drive Motor Assembly
When adjusting this screw, do not turn it farther
d. Removal. Tag and disconnect electrical lead
than it will turn easily.
c. To increase DIFFERENTIAL and maintain
remove drive motor assembly.
same CUT-OUT pressure, turn differential screw at
b. Installation. Install the drive motor on the
edge clockwise and at the same time turn center
c. Belt Adjustment. Loosen the drive motor
If differential is increased only by
holdown bolts (4) and slide the motor on the base
turning screw at edge clockwise, the
to give the belt a 1-/2 inch deflection between pulleys.
cut-in pressure changes only slightly
Tighten the motor holddown bolts (4).
and the cut-out pressure rises.
Air Compressor Unloader
a. Removal. Loosen setscrew and remove sheeve.
b. Installation.Place sheeve on drive motor shaft
12 and remove and disassemble the unloader.
and tighten setscrew finger-tight.
b. Cleaning and Inspection.
c. Alignment. Place a straight edge on the air
(1) Clean parts with cleaning solvent and dry
compressor pulley and align the drive motor sheeve
to the straight edge and tighten the setscrew.
(2) Inspect for rust or corrosion that could
Air Compressor Pressure Switch
cause improper fit and function of the unloader.
a. To raise CUT-IN and CUT-OUT pressure,
c. Reassembly and Installation. Reassemble and
b. To lower DIFFERENTIAL (namely, the
difference between cut-in and cut-out pressure),