TM 5-3805-280-24-1
Theory of Operation
return passage (V). The flow of oil through the orifices
Pilot oil from the pilot pump (M) flows to the control
causes a pressure drop; the pressure of oil
valve and through the orifices (D) into the propel pilot
downstream of each orifice is less than the pressure
pressure signal passage (G) and dig pilot pressure
upstream of the orifices. None of the switches or
signal passage (H). The oil in the propel pilot pressure
valves in the signal passages are actuated.
signal passage flows to the propel pressure switch (E),
the propel-boom down selector valve (R), past the top
When a function is actuated, the valve spools shift
end of the right (I) and left (W) propel valve spools,
blocking the flow of oil through the signal passage.
and then to the return passage (X). The oil in the dig
The oil pressure upstream of the valve spool increases
pilot pressure signal passage flows to the dig pressure
to approximately the pressure setting of pilot pressure
switch (C), the propel flow control valve (T), flow
regulating valve and actuates the switch and valves in
combiner valve (F), past the top end of bucket (J),
that signal passage.
boom I (K), arm II (L), swing (P), arm I (Q), boom II
(S), and auxiliary (U) valve spools, and then to the
TX,05,GG2192
1920MAY982/2
9025
05
39
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