TM 5-3805-280-24-1
Theory of Operation
Speed Sensing--When the actual engine speed,
Summation (flow rate control by monitoring both pump
measured by engine speed sensor, is pulled down to
pressures)--The pump supply oil pressure (load) for
the target engine speed, as determined by engine rpm
each pump is sensed at the load piston (11) through
dial position, the speed sensing solenoid valve coil is
the pump pressure inlets (12) at its regulator and at
energized by an electrical signal from the engine and
the regulator of other pump. The average pressure on
pump controller. The pilot oil control signal is sent to
the load piston is applied through the load spool (10)
the end of load piston at the speed sense signal port
to the inner and outer springs. The springs are
(13) in the front and rear pump regulators. The pilot oil
adjusted against the average pressure so the flow rate
control signal along with the pump supply oil pressure
of the pumps are approximately equal and each pump
shift the load spools against the springs opening a
uses approximately half the engine output. If the load
path for pilot oil to the large end of servo pistons to
on either pump increases, the average pressure on the
decrease the pump angle. The flow rate of both pumps
load pistons shift the load spools against the springs
decreases so the load on the engine decreases and
opening a path for pilot oil to the servo pistons. The
the actual engine speed can increase. (See Engine
flow rate of both pumps decreases so the load on the
Speed Sensing Control Circuit Operation in this group.)
pumps does not exceed the engine output. Also
engine output is not exceeded even if one pump is
loaded relatively high while the other pump stays
relatively low.
TX,05,GG2205
1920MAY982/2
9025
05
25
6-24
