Mow Circuit - Toro Greensmaster 3120 Service Manual

Mow Circuit

Mow (machines without backlap)
Hydraulic System: Hydraulic Flow Diagrams
The tandem gear pump is directly coupled to the piston (traction) pump. The
front gear pump section (P2) supplies fluid flow to the mower manifold and to the
cutting reel motors. The gear pump takes its suction directly from the hydraulic
tank.
With the engine running and the function control and joystick levers positioned
so the reels will not turn; refer to the traction unit Operator's Manual, solenoid
relief valve (S1) in the mower manifold is de-energized. The de-energized (S1)
by-passes flow from the front gear pump section (P2) to the hydraulic filter and
back to the tank. Additionally, the pilot operated relief valve (PRV) in the mower
manifold will remain seated to prevent the reel motors (and reels) from rotating.
With the engine running and the function control and joystick levers positioned to
lower and engage the cutting units; refer to the traction unit Operator's Manual,
solenoid valve (S1) is energized to direct fluid flow toward the reel motors; refer
to Figure 22. Mow circuit pressure will cause the pilot piston under the pilot
operated relief valve (PRV) to shift and open the valve. The shifted relief valve
allows fluid to exit the reel motors and return to the tank through the mower
manifold, hydraulic filter and optional hydraulic fluid cooler (if equipped). The reel
motors are connected in series. Fluid flows through the left front reel motor, then
the right front reel motor and then the center reel motor to turn the reel motors in
the mow direction. Maximum circuit pressure is limited to 20,684 kPa (3000 psi)
by relief valve (R1) which is located in the mower manifold.
Page 4–20 Greensmaster 3120
17230SL Rev C