SECTION II. EQUIPMENT DESCRIPTION AND DATA
1-6. Characteristics, Capabilities, and Features. A very broad view of the air compressor unit is as follows:
(1) Single-acting, two-stage, belt-driven, two cylinder, electric-driven.
(2) Air cooled.
(3) Controlled at the pilothouse or engine room console.
b. Capabilities and Features.
(1) Capable of delivering required air pressure (200 psi) at lower temperatures than a single-stage air
(2) The pulley is finned to also act as a fan and move air over the intercooler to lower output air
(3) Lubricated by means of a positive displacement rotary type oil pump.
1-7. Location and Description of Major Components. See FIGURE 1-1. The QR-25, Model 340 air
compressor is a single-acting, two-stage, belt-driven, two cylinder, air cooled unit. The compressor is mounted
on a separate base that includes the air compressor and electric motor. The motor drives two vee belts, which
in turn drive a pulley attached to the compressor crankshaft. The air compressor unit includes a base, an
electric motor, vee belts, belt guard, intercooler, hydraulic unloader, and the air compressor.
a. Air Compressor (FIGURE 1-1). Crankcase, cylinder block and head, containing crankcase,
connecting rods, and pistons to generate air pressure.
b. Bearing Carrier (14). Contains the crankshaft bearing ring and oil pump.
c. Hydraulic Unloader (10). Allows excessive pressure to be unloaded.
d. Intercooler (9). Cools air between compressor stages.
e. Electric Motor (7). Provides the drive power.
f. Vee Belt (6). Provides belt drive.
g. Pulley (15). Rotates crankshaft and cools the intercooler.
1-8. Equipment Data
. Characteristics and reference data are provided
in Table 1-1. Also see the equipment
data given in the operator's manual TM 55-1905-223-10.