TM-9-2350-311-34-2

TM 9-2350-311-34-2

1-14 LOCATION AND DESCRIPTION OF MAJOR COMPONENTS - CONTINUED

1-14.11 Location and Description of Power Pack Assembly - Continued

Direct Current Motor. The direct current motor (3) is a 5-horse power, compound-wound, waterproof, fully enclosed,

sealed motor. Through a coupling, it drives rotary pump (9). ON and OFF operation of the direct current motor is con-

trolled by main accumulator pressure switch (10) and hydraulic pump motor relay.

Cover Reservoir and Body Regulator Valve. The cover reservoir and body regulator valve (4) keeps operating hydrau-

lic fluid pressure at a constant level. For a given input handle position, a system output will be maintained at a constant

speed.

Power Valve. The power valve (5) provides operating pressure for elevating, traversing, and ramming systems. The

power valve, operated by a solenoid (11) is activated when CAB POWER switch is placed in ON position.

Filter. The internal filter (6) on M109A2/M109A3 howitzers connects top of rotary pump (9) to cover of power pack

reservoir (2). The two hydraulic external filters (7) on M109A4/M109A5 howitzers connect to the drain and pressure

lines coming from the power pack assembly (1). The filter(s) prevents foreign particles, which may be present in the

reservoir hydraulic fluid supply, from entering the valve system.

Fluid Level Gage. The fluid level gage (8) is located on the cover of power pack reservoir (2) within the strainer. It con-

sists of a filler cap, filter element, and dipstick. It is used for measuring and filling the power pack reservoir with hydrau-

lic fluid. The strainer is an additional filter to filter out foreign matter from hydraulic fluid being added to the power pack

reservoir.

Hydroscopic Breather and Air Line Filter (M109A4/M109A5 howitzers). The hydroscopic breather (12) and air line filter

(13) are located at the bottom of a power pack drain line. They filter accumulated air and condensation trapped in the

hydraulic system due to oil temperature fluctuations and exposure during maintenance.

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