Greensmaster 3250--D Hydraulic SystemPage 4 -- 1 7
Mow and Backlap
The tandem gear pump is directly coupled to the piston
(traction) pump. The front gear pump section supplies
oil flow tothe hydraulic manifold block and to the cutting
reel motors. The gear pump takes its suction directly
from the hydraulic reservoir. Maximum circuit pressure
islimitedbysolenoidreliefvalve(S1R1)whichislocated
in the hydraulic manifold.
With the engine running and the Functional Control and
Raise/Lower/Mow levers positioned so the reels will
not turn, solenoid relief valve (S1R1) in the hydraulic
manifold is de--energized. The de--energized (S1R1)
by--passes flow from the front section of the gear pump
totheoilfilterandhydraulicreservoir.Additionally,man-
ifold pressure reducing valve (PRV) will remain seated
to prevent the reel motors (and reels) from rotating.
Mow
With the engine running and the Functional Control and
Raise/Lower/Mow levers positioned so the reels will
turn,solenoidreliefvalve(S1R1)isenergized.Intheen-
ergizedposition,thisvalvedirectsoilflowtothereelmo-
tors and also functions as the mow circuit relief valve.
Oil flow from manifold port (P1) flows through the reel
speedcontrolvalve(FC).Flowacrossthespeedcontrol
valve is pressure compensated by the logic cartridge
valve (LC). The logic cartridge valve maintains a pres-
sure differential of 75 PSI (5.2 bar) across the speed
control valve. Any excess flow above the speed control
valve setting is by--passed to t he reservoir through the
logiccartridgevalve.With the backlap valve(MR) in the
mow position, oil flows through the backlap valve, out
manifold port (MA) and to the reel motors that are con -
nectedinseries.Oilflowsthroughtheleft,righta ndthen
centerreelmotorasitturnsthemotorsinthemowdirec-
tion.
When in the mow position, mow circuit pressure will
cause the hydraulic manifold pilot piston to shift and
open the pressure reducing valve (PRV). The shifted
pressurereducingvalve allows circuit oil to return to the
reservoir through the manifold block and oil filter.
Backlap
Backlapping operation is the same as mowing opera-
tion, except for the position of the backlap valve (MR).
Whenthebacklapvalve(MR)isin thebacklapposition,
oilflowsthroughthecenter,rightandthenleftreelmotor
as it turns the motors in the backlap direction.
Hydraulic
System
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