Toro Greensmaster 3120 - Page 68

Mow(machineswithbacklap)
Withtheenginerunningandthefunctioncontrolandjoystickleverspositionedso
thereelswillnotturn(refertothetractionunitOperator’sManual),solenoidrelief
valve(S1R1)inthemowermanifoldisde-energized.Thede-energized(S1R1)
by-passesowfromthefrontgearpumpsectiontothehydrauliclterandtank.
Additionally,pilotoperatedreliefvalve(PRV)willremainseatedtopreventthe
reelmotors(andreels)fromrotating.
Withtheenginerunningandthefunctioncontrolandjoystickleverspositionedto
lowerandengagethecuttingunits(refertothetractionunitOperator’sManual),
solenoidreliefvalve(S1R1)isenergizedtodirectuidowtowardthereelspeed
controlvalve(FC1)andthereelmotors;refertoFigure23.Solenoidreliefvalve
(S1R1)andalsofunctionsasthemowcircuitreliefvalve,limitingcircuitpressure
to17,236kPa(2500psi).Toprovideprecisereelspeedcontrol,owmoving
acrossthespeedcontrolvalve(FC1)ispressurecompensatedbythelogic
cartridgevalve(LC).Thelogiccartridgevalvemaintainsapressuredifferential
of517kPa(75psi)acrossthespeedcontrolvalve.Anyexcessowabovethe
speedcontrolvalvesettingisby-passedtothetankthroughthelogiccartridge
valve.
Withthebacklapvalve(MR)inthemowposition,uidowsoutthe(MA)portof
themowermanifoldandtothereelmotors.Thereelmotorsareconnectedin
series.Fluidowsthroughtheleftfrontreelmotor,thentherightfrontreelmotor
andthenthecenterreelmotortoturnthereelmotorsinthemowdirection.Mow
circuitpressurewillcausethepilotpistonunderthepilotoperatedreliefvalve
(PRV)toshiftandopenthevalve.Theshiftedreliefvalveallowsuidtoexitthe
reelmotorsandreturntothetankthroughthemowermanifold,hydrauliclter
andoptionalhydraulicuidcooler(ifequipped).
Backlap
Thebacklapoperationisthesameasmowingoperation,exceptfortheposition
ofthebacklapvalve(MR).Whenthebacklapvalve(MR)isinthebacklap
position,uidowsthroughthebacklapvalve,outthe(MB)portofthemower
manifoldandtothereelmotorsthatareconnectedinseries.Fluidowsthrough
thecenterreelmotor,rightfrontmotorandthenleftfrontmotorasitturnsthe
reelmotorsinthebacklapdirection.
HydraulicSystem:HydraulicFlowDiagrams
Page4–22
Greensmaster3120
17230SLRevC