Reelmaster 5010 Series Hydraulic System (Rev. C)Page 4 -- 15
Lift Circuit: Lower Cutting Units
A four section gear pump is coupled to the piston (trac-
tion) pump. Gear pump s ection (P4) supplies hydraulic
flow to the lift control manifold and ultimately for the lift
cylinders. The gear pump takes its suction from the hy-
draulic reservoir. Lift circuit pressure is limited to 2000
PSI (138 bar) by a solenoid relief valve (SVRV) located
in the lift control manifold.
The lift control manifold includes four(4) electrically op-
erated solenoid valves. Valve (SVRV) is used to direct
gear pump flow to the lift cylinders when energized or
bypass pump flow back to the reservoir when de--ener-
gized.Valve ( SV2) isusedtodirectoilflowto retractthe
lift cylinders when energized or extend them when de--
energized.Valve(SV1)allowshydraulicflow tothefront
lift cylinders when energized. Valve (SV3) allows hy-
draulic flow to the rear lift cylinders when energized.
Liftcircuitpressure can bemonitoredatlift controlman-
ifold port G4.
The Electronic C ontrol Module ( ECM) uses inputs from
various machine switches to determine when lift man-
ifold solenoid valves (SV1, SV2, SV3 and SVRV) are to
be energized. The ECM also provides a partial raise
position of the front outside cutting units.
During conditions of not raising or lowering the cutting
units(joystickintheneutral(center)position),allfour(4)
liftmanifoldsolenoidvalves(SV1,SV2,SV3andSVRV)
are de--energized. Hydraulic flow from gear pump sec-
tion(P4)by--passestheliftcylinderstotheoilcoolerand
then to the hydraulic reservoir.
Lower Cutting Units (Fig. 12)
When the joystick is moved to the lower position, sole-
noidvalve(SVRV)energizesalongwithsolenoidvalves
(SV1)and(SV3).Solenoid valve (SV2) is initsnormally
de-energized position, and directs oil flow to the piston
end of the lift cylinders. Hydraulic pressure against the
piston side of the cylinder causes the shafts to extend,
and lower the cutting units. The piloted check valves in
the lift control manifold (CV1, CV4, CV5 and CV23) are
shifted by hydraulic pressure to allow return flow from
the extending lift cylinders. Fixed orifices in the lift con-
trol manifold (C1, C4, C5 and C23) control the lowering
speed by providing a restriction for the return flow from
the lift cylinders.
Because c utting unit w eight assists in extending the lift
cylinderswhen loweringthecuttingunits,lesshydraulic
pressure is necessary during the cutting unit lowering
operation.Liftcircuitlowerreliefv alve(R7)allowsliftcir-
cuitpressure to be limitedto500PSI (34bar)whilelow-
ering the cutting units.
NOTE: Adjustment of lift circuit lower relief valve (R7)
is not recommended.
When the joystick is r eturned to the neutral (center)
position, the solenoid valves are de--energized and the
lift cylinders (and cutting units) are held in the lowered
position.
Hydraulic
System
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