Toro Groundsmaster 5900 Series - Page 130

PTOCircuitRelief
1.5 CID
PRV
3000 PSI
P1
P2
M1
M2
LEFT DECK
OR1
.063”
LC110 PSI
SQ
110 PSI
OR2 .025”
600 PSI
RV
LC2
10 PSI
CD
G1
PUMP
RETURN
FLOW
PRV ENERGIZED
LC1 SHIFTED
PTO SWITCH OFF
g287730
Figure43
Maximummowcircuitpressureislimitedforeachdeckbytheproportional
reliefvalve(PRV)inthehydrauliccontrolmanifold.Thefrontandleftdeck
reliefvalvesaresetat207bar(3000PSI)andtherightdeckreliefvalveisset
at138bar(2000PSI).
Proportionalreliefvalve(PRV)andlogiccartridge(LC1)worktogetherasa
circuitrelief.Whenincreasedcircuitresistanceismetorifacuttingbladeshould
strikeanobject,thepressureincreaseisfeltatthereliefvalve(PRV).Ifthe
pressureshouldexceedthereliefvalve(PRV)setting,thereliefvalve(PRV)
willopen,creatingasmallamountofhydraulicowtoreturntotankthrougha
manifoldsensingline.Thisowcausesapressureincreasethatshiftslogic
cartridge(LC1)anddivertscircuitowawayfromthedeckmotortomanifold
portP2(Figure43).Whencircuitpressurelowers,reliefvalve(PRV)closes
whichreturnslogiccartridgeLC1backtoitsneutralpositionallowingcircuitow
toreturntothedeckmotor.
HydraulicSystem:HydraulicFlowDiagrams
Page5–30
Groundsmaster
®
5900&5910
16227SLRevB