SkyTrak 6036 Service Manual - Manual (Page 165)

Section 9 Hydraulic System
Model 6036/6036T S/N 9B0500 thru 14833 9-15
Fig. 9.11 Electronic Control Boom Extend/Retract Circuit
b. Pressure Checks and Adjustments
Refer to paragraph 9.6.2.h for control valve
pressure checks and adjustments.
MA3020
RELIEF VALVE
2850 PSI
PRESSURE
COMPENSATED
INLET
RAISE/LOWER
WORKING SECTION
EXTEND/ RETRACT
WORKING SECTION
INLET
RELIEF
VALVE
2650 PSI
BYPASS
VALVE
15
GPM
30
GPM
TANDEM PUMP
RESERVOIR
RETURN FILTER
STRAINER
C2 C1
T P
EXTEND
CENTER
RETRACT
EXTEND
RETRACT
CONTROL VALVE
EXTEND
PWM
RETRACT
PWM
COMPENSATOR
VALVE TO BOOM
RAISE/LOWER
CYLINDER
PILOT VALVE
200 PSI
OUTLET
BOOM EXTEND CYLINDER
COUNTERBALANCE
VALVE
PULSAR
SOLENOID
PULSAR
SOLENOID
The pilot valve reduces the pressure to 200 psi
(13,8 bar). This filtered supply is directed to the
pilot stage and pulsar solenoids in the extend/
retract working section.
All return oil flows to the return filter and reser-
voir. If the filter becomes clogged, hydraulic oil
will bypass the filter when the pressure reaches 10
to 15 psi
(0,69 to 1,03 bar).
Center Position
When the joystick is placed in the center or neutral
position, no PWM signals are sent to the extend or
retract pulsar solenoid. The control valve spool is
centered so that supply pressure is blocked at port
P and supply pressure in the supply passage acts
on the compensator spring to keep the valve
closed. Load sensing pressure is vented back to
the reservoir through the inlet relief valve.
9.3.4 Boom Extend/Retract Circuit
a. Description
Hydraulic pressure is applied in the boom extend/
retract circuit by the 30 gpm section (rear half) of
the tandem pump, which draws its fluid through a
suction strainer in the reservoir, Fig. 9.11. The
supply pressure enters the inlet section and is
directed to the pilot valve filter, and through the
supply passage to the extend/retract working
section. When the supply pressure reaches 200
psi
(13,8 bar), the bypass (compensator) valve
opens to bypass the oil to return. The inlet relief
valve is set at 2650 psi
(182,6 bar).