Toro Groundsmaster 5900 Series - Page 129

Eachofthethree(3)cuttingdecksiscontrolledbyahydrauliccontrolmanifold
equippedwithaproportionalreliefvalve(PRV),logicvalves(LC1)and(LC2),a
sequencevalve(SQ)andabrakereliefcartridge(RV).Theproportionalrelief
valveisasolenoidoperatedvalvethatalsofunctionsasthecircuitreliefvalve
whenthevalveisenergizedbytheslaveT oroElectronicController(TEC).Mow
circuitpressurecanbemeasuredatport(G1)ofthehydraulicmanifoldforeach
cuttingdeck.
Note:Toengagethemowcircuit,theoperatormustbeintheoperatorseat,the
tractionspeedmustbeintheLOWspeed(mow)position,thePTOswitchmust
beONandthecuttingdeck(s)mustbefullylowered.
PTONotEngaged
WhenthePTOswitchisOFForifthedeckisraisedwiththePTOswitchON,the
PTOmanifoldproportionalreliefvalve(PRV)isnotenergizedbytheslaveTEC
whichallowsasmallamountofhydraulicowthroughthevalve.Asthishydraulic
owreturnstothehydraulicreservoir,acircuitpressureincreaseshiftslogic
valveLC1.ThepumpowisroutedthroughshiftedLC1andoutmanifoldport
P2bypassingthecuttingunitmotor.Sequencevalve(SQ),pilotdirectionvalve
(PD)andreliefvalve(RV)remainintheunshiftedpositiontopreventanyowto
orfromthedeckmotorwhichkeepsthemotorandcuttingbladesfromrotating.
Returnowfromthefrontandrightdeckcontrolmanifoldsisroutedthroughthe
oilcooler,oillterandthentothegearpumpinput.Returnowfromtheleftdeck
controlmanifoldprovidessupplyfortherightdeck.
PTOEngaged
WhenthePTOswitchisturnedONandthedecksarelowered,thePTOmanifold
proportionalreliefvalve(PRV)isenergizedbytheslaveTEC.Thisshifted
solenoidvalvepreventsanyowthroughthevalvewhichallowsthelogicvalve
LC1tobeinitsneutralpositiondirectingcircuitowtowardthecuttingdeck
motor.GearpumpowenteringthemanifoldisroutedoutmanifoldportM1and
tothecuttingdeckmotor.Ascircuitpressureincreases,thesequencevalve
(SQ)andthenthelogicvalve(LC2)shifttoallowthemotorandcuttingbladesto
rotateandtoprovideareturnpathforcircuitow.Thereturnowfromthedeck
motorre−entersmanifoldportM2,isroutedthroughshiftedlogicvalve(LC2)and
outmanifoldportP2.Returnowfromthefrontandrightdeckcontrolmanifolds
isroutedthroughtheoilcooler,oillterandthentothegearpumpinput.Return
owfromtheleftdeckcontrolmanifoldprovidessupplyfortherightdeck.Flowfor
thedeckmotorcontinuesaslongasproportionalreliefvalve(PRV)isenergized.
Deckmotorcasedrainleakagereturnsdirectlytothehydraulicreservoir.
Groundsmaster
®
5900&5910
Page5–29
HydraulicSystem:HydraulicFlowDiagrams
16227SLRevB